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Sample records for modeling gypsum plaster

  1. PPF-reinforced, ESP-lightened gypsum plaster

    Directory of Open Access Journals (Sweden)

    García Santos, A.

    2009-03-01

    Full Text Available A new construction material has been obtained by adding aggregate to gypsum plaster which, without reducing the bending strength of plain gypsum plaster without aggregates, lowers its density, and consequently the weight of the construction elements made from the agglomerated material, by half.The aggregates used were expanded polystyrene beads and short polypropylene fibre.The new material addresses one of the issues of cardinal interest in construction materials and construction element research, namely the need to lighten materials so as to ease the burden on buildings’ bearing structures while facilitating assembly of construction units, by a single worker wherever possible.With a water / binder ratio of 0.7 and 2% (by weight of plaster of expanded polystyrene and 2% of polypropylene fibre aggregates, the decline in density achieved was 50,88% over plain gypsum plaster and 32.88% over plasterboard.Se ha obtenido un nuevo material de construcción aditivando el yeso o la escayola, mediante la incorporación de agregados, de modo que sin reducir la resistencia a flexotracción de una escayola sin ningún tipo de adición, reduce su densidad a la mitad, y por tanto, el peso de los elementos constructivos que puedan realizarse basándose en él.El material está compuesto por una adición de gránulos de poliestireno expandido y fibras cortadas de polipropileno.El nuevo material incide sobre aquellos aspectos de más interés en el campo de la investigación en construcción, en donde se intenta reducir el peso de los materiales, de modo que se grave lo menos posible la estructura resistente de las edificaciones, a la par que se facilitan los procedimientos de montaje de las unidades constructivas, al poder ser manejadas por un solo operario.La escayola, con relación de agua/conglomerante de 0,7, y con adiciones del 2% en peso (sobre la cantidad de escayola, tanto de poliestireno expandido como de fibras de polipropileno, permite reducir la

  2. Estimates of inhalation doses resulting from the possible use of phospho-gypsum plaster-board in Australian homes.

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    O'Brien, R S; Peggie, J R; Leith, I S

    1995-04-01

    Current materials used as internal lining in Australian buildings are based on natural gypsum of low radium content. A study was carried out to estimate the contribution to the annual effective dose due to airborne contamination from chemical by-product gypsum plaster-board of higher radium content if it were used as an internal lining. The 226Ra content and 222Rn exhalation rate were measured for several samples of the plaster-board, and the behavior of 222Rn and its progeny (218Po, 214Pb, 214Bi, and 214Po) in a typical building was modeled numerically, using the results of the exhalation rate measurements as input. For building ventilation rates greater than approximately 0.5 air changes per hour, the contribution to the total annual effective dose from inhalation of 222Rn and its progeny exhaled from the phospho-gypsum plaster-board is estimated to be below 1 mSv. This contribution is reduced if the surface of the plaster-board is coated with paint or cardboard, or if the very fine particles are removed from the phospho-gypsum during manufacture of the plaster-board. The effective doses arising from dust generation during the installation of the plaster-board are also estimated to be below 1 mSv. The recommended action level of 200 Bq m-3 for radon in air in Australia corresponds to an annual effective dose of approximately 6 mSv. The study indicates that the suggested acceptable level of 185 Bq kg-1 for the 226Ra concentration in the plaster-board may be too restrictive under Australian conditions.

  3. The influence of composition of gypsum plaster on its technological properties

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    M. Pawlak

    2010-10-01

    Full Text Available Gypsum plasters used in art and precision foundry always are the composition of gypsum-silica-cristobalite. It is necessary considering the specifity of plaster during heating stage. Plaster undergoes then, structural transformations causing significant variations of its volume which are nonuniform and proceed with different intensity. The content of silica and cristobalite reduces dimensional variations of setted gypsum plaster what increases dimensional accuracy and significant stresses reduction limiting the possibility of mould cracks occurrence during heating.The influence of cristobalite and silica addition on basic gypsum plaster properties like setting time, dimensional changes after setting, bending strength and permeability in raw and heat treated state are presented in this paper. Experiments were done for mixes containing 30÷70% of the gypsum. It was proven that cristobalite has the biggest influence on the bounding time and expansion of the sandmix and the strength and permeability do not depend on the type of additions and only on theirs total amount in the composition.

  4. Consolidation of archaeological gypsum plaster by bacterial biomineralization of calcium carbonate.

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    Jroundi, Fadwa; Gonzalez-Muñoz, Maria Teresa; Garcia-Bueno, Ana; Rodriguez-Navarro, Carlos

    2014-09-01

    Gypsum plasterworks and decorative surfaces are easily degraded, especially when exposed to humidity, and thus they require protection and/or consolidation. However, the conservation of historical gypsum-based structural and decorative materials by conventional organic and inorganic consolidants shows limited efficacy. Here, a new method based on the bioconsolidation capacity of carbonatogenic bacteria inhabiting the material was assayed on historical gypsum plasters and compared with conventional consolidation treatments (ethyl silicate; methylacrylate-ethylmethacrylate copolymer and polyvinyl butyral). Conventional products do not reach in-depth consolidation, typically forming a thin impervious surface layer which blocks pores. In contrast, the bacterial treatment produces vaterite (CaCO3) biocement, which does not block pores and produces a good level of consolidation, both at the surface and in-depth, as shown by drilling resistance measurement system analyses. Transmission electron microscopy analyses show that bacterial vaterite cement formed via oriented aggregation of CaCO3 nanoparticles (∼20nm in size), resulting in mesocrystals which incorporate bacterial biopolymers. Such a biocomposite has superior mechanical properties, thus explaining the fact that drilling resistance of bioconsolidated gypsum plasters is within the range of inorganic calcite materials of equivalent porosity, despite the fact that the bacterial vaterite cement accounts for only a 0.02 solid volume fraction. Bacterial bioconsolidation is proposed for the effective consolidation of this type of material. The potential applications of bacterial calcium carbonate consolidation of gypsum biomaterials used as bone graft substitutes are discussed.

  5. Populations of some molds in water-damaged homes may differ if the home was constructed with gypsum drywall compared to plaster

    Science.gov (United States)

    Starting in the 1940s, gypsum drywall began replacing plaster and lathe in the U.S. home construction industry. Our goal was to evaluate whether some mold populations differ in water- damaged homes primarily constructed with gypsum drywall compared to plaster. The dust samples fr...

  6. Populations of some molds in water-damaged homes may differ if the home was constructed with gypsum drywall compared to plaster

    Science.gov (United States)

    Starting in the 1940s, gypsum drywall began replacing plaster and lathe in the U.S. home construction industry. Our goal was to evaluate whether some mold populations differ in water- damaged homes primarily constructed with gypsum drywall compared to plaster. The dust samples fr...

  7. Effect of different forms of silica on the physical and mechanical properties of gypsum plaster composites

    Directory of Open Access Journals (Sweden)

    Khalil, A. A.

    2013-12-01

    Full Text Available Gypsum plaster/silica composites prepared by dry blending (0.2-10 % natural sand, silica fume or silica gel and subsequently hydrated. Their physical and mechanical properties, including normal consistency, setting time, apparent porosity, bulk density and compressive strength, were determined after hydration for 7- and 28-days. The results indicated that adding different forms of silica lowered the bulk density and increased the normal consistency, setting time, apparent porosity and, to some limited extent, compressive strength of the composites. This improvement in properties can be attributed to the existence of silica in the interstitial pores in the hardened plaster matrices. While most of the composites revealed only scant rises in compressive strength, their composition was beneficial in so far as it included either a readily available low-cost constituent (sand or industrial by-products. Consequently, the formed plaster-silica composites are of economic value, contribute to a cleaner environment by minimizing waste and can be used for applications where high porosity, lightweight units are required or recommended for low-cost buildings.Se prepararon pastas compuestas de yeso y sílice mediante la mezcla en seco de yeso con distintas proporciones (0,2- 10 % de arena natural, o gel o humo de sílice, procediéndose a continuación a su hidratación. A fin de determinar las propiedades físicas y mecánicas de las pastas, a los 7 y los 28 días de hidratación se hallaron su fluidez, tiempo de fraguado, porosidad aparente, densidad aparente y resistencia a la compresión. Los resultados obtenidos indican que al incorporar las distintas modalidades de sílice a la mezcla, disminuyó la densidad aparente y aumentaron la fluidez, el tiempo de fraguado, la porosidad aparente y, en menor medida, la resistencia a la compresión de las muestras. Se considera que esta mejora de las propiedades del material se debe a la presencia de sílice en los

  8. The Potential Ability of Plaster to Cause Breast Cancer as Indicated by CA15-3 and CEA Antigens in Women Working in Gypsum Factory

    Directory of Open Access Journals (Sweden)

    Ali Abdul Hussein S. AL-Janabi

    2017-07-01

    Full Text Available Plaster is an important form of gypsum that mainly used in building construction. Breast cancer was investigated among women exposure to the dust of such material. The levels of CA15-3 and carcinoembryonic antigens (CEA as indicators for breast cancer were measured in the serum of 120 women working in a plaster factory. All of involved women showed a normal level of CEA, while 12.5% of them had moderately elevated levels of CA15-3. In conclusion; plaster dust has no significant effect to cause breast cancer in working women. Moderately high levels of CA15-3 in some of exposed women may relate to liver diseases. Key words: Breast Cancer, Plaster, CA15-3, CEA

  9. Gypsum

    Science.gov (United States)

    Crangle, R.D.

    2013-01-01

    The United States is the world’s fifth ranked producer and consumer of gypsum. Production of crude gypsum in the United States during 2012 was estimated to be 9.9 Mt (10.9 million st), an increase of 11 percent compared with 2011 production. The average price of mined crude gypsum was $7/t ($6.35/st). Synthetic gypsum production in 2012, most of which is generated as a flue-gas desulphurization product from coal-fired electric powerplants, was estimated to be 11.8 Mt (13 million st) and priced at approximately $1.50/t ($1.36/st). Forty-seven companies produced gypsum in the United States at 54 mines and plants in 34 states. U.S. gypsum exports totaled 408 kt (450,000 st). Imports were much higher at 3.2 Mt (3.5 million st).

  10. The Aspects About of Objectively Appraisals of Modeling Gypsum Quality and Composites of Phonic-Absorbent and Orthopedic on Base of Gypsum

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    Pop, P. A.; Ungur, P. A.; Lazar, L.; Marcu, F.

    2009-11-01

    The EU Norms about of protection environment, outside and inside ambient, and human health demands has lead at obtain of new materials on the base of airborne material, with high thermo and phonic-absorbent properties, porous and lightweight. The α and β-modeling gypsum plaster quality and lightweight depend on many factors as: fabrication process, granulation, roast temperature, work temperature, environment, additives used, breakage, etc. Also, the objectively appraisal of modeling gypsum quality depends of proper tests methods selection, which are legislated in norms, standards and recommendations. In Romanian Standards SR EN 13279-1/2005 and SR EN 13279-2/2005, adaptable from EU Norms EN 13279-1/2004 and EN 13279-2/2004, the characteristics gypsum family tests are well specification, as: granule-metric analysis, determination of water/plaster ratio, setting time, mechanical characteristics, adhesions and water restrain. For plaster with special use (phonic-absorbent and orthopedic materials, etc.) these determinations are not concluding, being necessary more parameters finding, as: elastic constant, phonic-absorbent coefficient, porosity, working, etc., which is imposed the completion of norms and standards with new determinations.

  11. Accuracy of stereolithographically printed digital models compared to plaster models.

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    Camardella, Leonardo Tavares; Vilella, Oswaldo V; van Hezel, Marleen M; Breuning, Karel H

    2017-03-30

    This study compared the accuracy of plaster models from alginate impressions and printed models from intraoral scanning. A total of 28 volunteers were selected and alginate impressions and intraoral scans were used to make plaster models and digital models of their dentition, respectively. The digital models were printed using a stereolithographic (SLA) 3D printer with a horseshoe-shaped design. Two calibrated examiners measured distances on the plaster and printed models with a digital caliper. The paired t test was used to determine intraobserver error and compare the measurements. The Pearson correlation coefficient was used to evaluate the reliability of measurements for each model type. The measurements on plaster models and printed models show some significant differences in tooth dimensions and interarch parameters, but these differences were not clinically relevant, except for the transversal measurements. The upper and lower intermolar distances on the printed models were statistically significant and clinically relevant smaller. Printed digital models with the SLA 3D printer studied, with a horseshoe-shaped base made from intraoral scans cannot replace conventional plaster models from alginate impressions in orthodontics for diagnosis and treatment planning because of their clinically relevant transversal contraction.

  12. Royal London space analysis: plaster versus digital model assessment.

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    Grewal, Balpreet; Lee, Robert T; Zou, Lifong; Johal, Ama

    2016-08-10

    With the advent of digital study models, the importance of being able to evaluate space requirements becomes valuable to treatment planning and the justification for any required extraction pattern. This study was undertaken to compare the validity and reliability of the Royal London space analysis (RLSA) undertaken on plaster as compared with digital models. A pilot study (n = 5) was undertaken on plaster and digital models to evaluate the feasibility of digital space planning. This also helped to determine the sample size calculation and as a result, 30 sets of study models with specified inclusion criteria were selected. All five components of the RLSA, namely: crowding; depth of occlusal curve; arch expansion/contraction; incisor antero-posterior advancement and inclination (assessed from the pre-treatment lateral cephalogram) were accounted for in relation to both model types. The plaster models served as the gold standard. Intra-operator measurement error (reliability) was evaluated along with a direct comparison of the measured digital values (validity) with the plaster models. The measurement error or coefficient of repeatability was comparable for plaster and digital space analyses and ranged from 0.66 to 0.95mm. No difference was found between the space analysis performed in either the upper or lower dental arch. Hence, the null hypothesis was accepted. The digital model measurements were consistently larger, albeit by a relatively small amount, than the plaster models (0.35mm upper arch and 0.32mm lower arch). No difference was detected in the RLSA when performed using either plaster or digital models. Thus, digital space analysis provides a valid and reproducible alternative method in the new era of digital records.

  13. Influence of the errors in an infrared camera on the estimation of thermal conductivity and thermal capacity of a gypsum plaster sample

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    Santana Magnani, Fábio; Nunes Tavares da Silva, Renata

    2013-03-01

    The present work studies how the errors of infrared cameras propagate during the estimation of thermophysical parameters. The errors in the camera were determined experimentally, and varied with both position and temperature. The thermal conductivity and thermal capacity were estimated by comparing the experimental and computational temperature evolution as a gypsum plaster sample was left to cool naturally in the air. For each study, one of the parameters was varied until the simulated temperature curve was adjusted to the experimental curve using the Levenberg-Marquardt Algorithm. We concluded that for the thermal capacity, there is a strong correlation between the error in the camera and the error of the parameter, which was not so clear in the case of the thermal conductivity. Another important conclusion is that the variation of the thermal conductivity presents a better adjustment of the curves even though the error in the estimated parameter was higher, indicating that reasonable results in the minimization process do not necessarily assure a good estimation. As a final conclusion, we stress the importance of using calibrated cameras, since in the extreme cases a mean deviation of 1.46 °C in the camera represented an error of 15% on the thermal capacity and a mean deviation of 0.81 °C in the camera represented an error of 25% on the thermal conductivity.

  14. Accuracy of laser-scanned models compared to plaster models and cone-beam computed tomography.

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    Kim, Jooseong; Heo, Giseon; Lagravère, Manuel O

    2014-05-01

    To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models. Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data. The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations>0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm±0.38 mm. In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

  15. Orthodontic measurements on digital study models compared with plaster models: a systematic review.

    Science.gov (United States)

    Fleming, P S; Marinho, V; Johal, A

    2011-02-01

    The aim of this study is to evaluate the validity of the use of digital models to assess tooth size, arch length, irregularity index, arch width and crowding versus measurements generated on hand-held plaster models with digital callipers in patients with and without malocclusion. Studies comparing linear and angular measurements obtained on digital and standard plaster models were identified by searching multiple databases including MEDLINE, LILACS, BBO, ClinicalTrials.gov, the National Research Register and Pro-Quest Dissertation Abstracts and Thesis database, without restrictions relating to publication status or language of publication. Two authors were involved in study selection, quality assessment and the extraction of data. Items from the Quality Assessment of Studies of Diagnostic Accuracy included in Systematic Reviews checklist were used to assess the methodological quality of included studies. No meta-analysis was conducted. Comparisons between measurements of digital and plaster models made directly within studies were reported, and the difference between the (repeated) measurement means for digital and plaster models were considered as estimates. Seventeen relevant studies were included. Where reported, overall, the absolute mean differences between direct and indirect measurements on plaster and digital models were minor and clinically insignificant. Orthodontic measurements with digital models were comparable to those derived from plaster models. The use of digital models as an alternative to conventional measurement on plaster models may be recommended, although the evidence identified in this review is of variable quality. © 2010 John Wiley & Sons A/S.

  16. Possibility of reconstruction of dental plaster cast from 3D digital study models

    OpenAIRE

    Kasparova, Magdalena; Grafova, Lucie; Dvorak, Petr; Dostalova,Tatjana; Prochazka, Ales; Eliasova, Hana; Prusa, Josef; Kakawand, Soroush

    2013-01-01

    Objectives To compare traditional plaster casts, digital models and 3D printed copies of dental plaster casts based on various criteria. To determine whether 3D printed copies obtained using open source system RepRap can replace traditional plaster casts in dental practice. To compare and contrast the qualities of two possible 3D printing options – open source system RepRap and commercially available 3D printing. Design and settings A method comparison study on 10 dental plaster casts from th...

  17. Reliability and validity of measurements on digital study models and plaster models.

    Science.gov (United States)

    Reuschl, Ralph Philip; Heuer, Wieland; Stiesch, Meike; Wenzel, Daniela; Dittmer, Marc Philipp

    2016-02-01

    To compare manual plaster cast and digitized model analysis for accuracy and efficiency. Nineteen plaster models of orthodontic patients in permanent dentition were analyzed by two calibrated examiners. Analyses were performed with a diagnostic calliper and computer-assisted analysis after digitization of the plaster models. The reliability and efficiency of different examiners and methods were compared statistically using a mixed model. Statistically significant differences were found for comparisons of all 28 teeth (P plaster model analysis appears to be an adequate, reliable, and time saving alternative to analogue model analysis using a calliper. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Comparison of linear measurements and analyses taken from plaster models and three-dimensional images.

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    Porto, Betina Grehs; Porto, Thiago Soares; Silva, Monica Barros; Grehs, Renésio Armindo; Pinto, Ary dos Santos; Bhandi, Shilpa H; Tonetto, Mateus Rodrigues; Bandéca, Matheus Coelho; dos Santos-Pinto, Lourdes Aparecida Martins

    2014-11-01

    Digital models are an alternative for carrying out analyses and devising treatment plans in orthodontics. The objective of this study was to evaluate the accuracy and the reproducibility of measurements of tooth sizes, interdental distances and analyses of occlusion using plaster models and their digital images. Thirty pairs of plaster models were chosen at random, and the digital images of each plaster model were obtained using a laser scanner (3Shape R-700, 3Shape A/S). With the plaster models, the measurements were taken using a caliper (Mitutoyo Digimatic(®), Mitutoyo (UK) Ltd) and the MicroScribe (MS) 3DX (Immersion, San Jose, Calif). For the digital images, the measurement tools used were those from the O3d software (Widialabs, Brazil). The data obtained were compared statistically using the Dahlberg formula, analysis of variance and the Tukey test (p plaster models using the caliper and from the digital models using O3d software were identical.

  19. Possibility of reconstruction of dental plaster cast from 3D digital study models.

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    Kasparova, Magdalena; Grafova, Lucie; Dvorak, Petr; Dostalova, Tatjana; Prochazka, Ales; Eliasova, Hana; Prusa, Josef; Kakawand, Soroush

    2013-05-31

    To compare traditional plaster casts, digital models and 3D printed copies of dental plaster casts based on various criteria. To determine whether 3D printed copies obtained using open source system RepRap can replace traditional plaster casts in dental practice. To compare and contrast the qualities of two possible 3D printing options--source system RepRap and commercially available 3D printing. A method comparison study on 10 dental plaster casts from the Orthodontic department, Department of Stomatology, 2nd medical Faulty, Charles University Prague, Czech Republic. Each of 10 plaster casts were scanned by inEos Blue scanner and the printed on 3D printer RepRap [10 models] and ProJet HD3000 3D printer [1 model]. Linear measurements between selected points on the dental arches of upper and lower jaws on plaster casts and its 3D copy were recorded and statistically analyzed. 3D printed copies have many advantages over traditional plaster casts. The precision and accuracy of the RepRap 3D printed copies of plaster casts were confirmed based on the statistical analysis. Although the commercially available 3D printing enables to print more details than the RepRap system, it is expensive and for the purpose of clinical use can be replaced by the cheaper prints obtained from RepRap printed copies. Scanning of the traditional plaster casts to obtain a digital model offers a pragmatic approach. The scans can subsequently be used as a template to print the plaster casts as required. Using 3D printers can replace traditional plaster casts primarily due to their accuracy and price.

  20. Moisture transport in coated plaster

    NARCIS (Netherlands)

    Goossens, E.L.J.; Van der Spoel, W.H.; Bancken, E.L.J.

    2001-01-01

    In the framework of the research project: 'Water balance of water-borne paint systems on plaster substrates in relation to fungal growth', a study is carried out to moisture transport mechanisms in coated gypsum plaster. In this contribution, the set-up of the study is described. Besides a descripti

  1. Moisture transport in coated plaster

    NARCIS (Netherlands)

    Goossens, E.L.J.; Van der Spoel, W.H.; Bancken, E.L.J.

    2001-01-01

    In the framework of the research project: 'Water balance of water-borne paint systems on plaster substrates in relation to fungal growth', a study is carried out to moisture transport mechanisms in coated gypsum plaster. In this contribution, the set-up of the study is described. Besides a descripti

  2. 用于外墙内侧、分户墙及顶棚补充节能的轻质石膏砂浆%Lightweight gypsum plaster used on exterior wall, party wall and ceiling for additional energy conservation

    Institute of Scientific and Technical Information of China (English)

    叶蓓红; 施嘉霖; 谈晓青; 曹禹

    2011-01-01

    轻质石膏砂浆作为粉刷石膏的一个新品种,主要用于墙面的找平层,同时对外墙内侧、分户墙及顶棚具有补充节能的作用.配制时宜选择表面玻化率高、密度小的玻化微珠作为轻骨料,其掺量为石膏量的20%~35%;当采用膨胀珍珠岩作为轻骨料时,其掺量为石膏量的15%~25%;纤维素醚掺量一般为石膏量的0.2%~0.4%;引气剂的掺量为粉料总量的0.6%~1.2%.按m(石膏):m(玻化微珠):m(纤维素醚):m(引气剂):m (SC缓凝剂)=770.0:215.0:4.1:5.0:2.3制备的轻质石膏砂浆导热系数为0.12 W/(m·K),通过计算,采用20 mm厚轻质石膏砂浆代替传统水泥砂浆,对200 mm厚混凝土隔墙进行双面抹灰后,保温效果提高38%.%As a new species of plaster, lightweight gypsum plaster is mainly used for wall leveling layer,meanwhile it has additional energy conservation effect when applied on the inside surface of external wall,party wall and ceiling. During preparation,glass beads with high surface vitrify rate and low density are selected as lightweight aggregate,and its dosage is 20%~35% of the gypsum amount;when expanded perlite is as lightweight aggregate,its dosage is 15%~25% of the gypsum amount;the dosage of cellulose ether is generally 0.22%~0.4% of the gypsum amount;the dosage of air-entraining agent (AEA) is 0.6%~1.2% of the total powder quantity. When m (gypsum) ∶m (glass beads) ∶m (cellulose ethers) ∶m (AEA) ∶m (SC retarder) =770.0∶215.0∶4.1∶5,0∶2.3, the prepared lightweight gypsum plaster has thermal conductivity of 0.12 W/(m·K). The calculation results show that the insulating effect will be increased by 38% if 20 mm-thick this type of plaster instead of the ordinary cement mortar is applied on both sides of the 200 mm-thick concrete wall.

  3. Digital versus plaster study models: how accurate and reproducible are they?

    Science.gov (United States)

    Abizadeh, Neilufar; Moles, David R; O'Neill, Julian; Noar, Joseph H

    2012-09-01

    To compare measurements of occlusal relationships and arch dimensions taken from digital study models with those taken from plaster models. Laboratory study The Orthodontic Department, Kettering General Hospital, Kettering, UK Methods and materials: One hundred and twelve sets of study models with a range of malocclusions and various degrees of crowding were selected. Occlusal features were measured manually with digital callipers on the plaster models. The same measurements were performed on digital images of the study models. Each method was carried out twice in order to check for intra-operator variability. The repeatability and reproducibility of the methods was assessed. Statistically significant differences between the two methods were found. In 8 of the 16 occlusal features measured, the plaster measurements were more repeatable. However, those differences were not of sufficient magnitude to have clinical relevance. In addition there were statistically significant systematic differences for 12 of the 16 occlusal features, with the plaster measurements being greater for 11 of these, indicating the digital model scans were not a true 11 representation of the plaster models. The repeatability of digital models compared with plaster models is satisfactory for clinical applications, although this study demonstrated some systematic differences. Digital study models can therefore be considered for use as an adjunct to clinical assessment of the occlusion, but as yet may not supersede current methods for scientific purposes.

  4. Accuracy and reproducibility of measurements on plaster models and digital models created using an intraoral scanner.

    Science.gov (United States)

    Camardella, Leonardo Tavares; Breuning, Hero; de Vasconcellos Vilella, Oswaldo

    2017-05-01

    The purpose of the present study was to evaluate the accuracy and reproducibility of measurements made on digital models created using an intraoral color scanner compared to measurements on dental plaster models. This study included impressions of 28 volunteers. Alginate impressions were used to make plaster models, and each volunteers' dentition was scanned with a TRIOS Color intraoral scanner. Two examiners performed measurements on the plaster models using a digital caliper and measured the digital models using Ortho Analyzer software. The examiners measured 52 distances, including tooth diameter and height, overjet, overbite, intercanine and intermolar distances, and the sagittal relationship. The paired t test was used to assess intra-examiner performance and measurement accuracy of the two examiners for both plaster and digital models. The level of clinically relevant differences between the measurements according to the threshold used was evaluated and a formula was applied to calculate the chance of finding clinically relevant errors on measurements on plaster and digital models. For several parameters, statistically significant differences were found between the measurements on the two different models. However, most of these discrepancies were not considered clinically significant. The measurement of the crown height of upper central incisors had the highest measurement error for both examiners. Based on the interexaminer performance, reproducibility of the measurements was poor for some of the parameters. Overall, our findings showed that most of the measurements on digital models created using the TRIOS Color scanner and measured with Ortho Analyzer software had a clinically acceptable accuracy compared to the same measurements made with a caliper on plaster models, but the measuring method can affect the reproducibility of the measurements.

  5. Digital model as an alternative to plaster model in assessment of space analysis.

    Science.gov (United States)

    Kumar, A Anand; Phillip, Abraham; Kumar, Sathesh; Rawat, Anuradha; Priya, Sakthi; Kumaran, V

    2015-08-01

    Digital three-dimensional models are widely used for orthodontic diagnosis. The purpose of this study was to appraise the accuracy of digital models obtained from computer-aided design/computer-aided manufacturing (CAD/CAM) and cone-beam computed tomography (CBCT) for tooth-width measurements and the Bolton analysis. Digital models (CAD/CAM, CBCT) and plaster model were made for each of 50 subjects. Tooth-width measurements on the digital models (CAD/CAM, CBCT) were compared with those on the corresponding plaster models. The anterior and overall Bolton ratios were calculated for each participant and for each method. The paired t-test was applied to determine the validity. Tooth-width measurements, anterior, and overall Bolton ratio of digital models of CAD/CAM and CBCT did not differ significantly from those on the plaster models. Hence, both CBCT and CAD/CAM are trustable and promising technique that can replace plaster models due to its overwhelming advantages.

  6. Polymer composites based on gypsum matrix

    Energy Technology Data Exchange (ETDEWEB)

    Mucha, Maria; Mróz, Patrycja; Kocemba, Aleksandra [Faculty of Process and Environmental Engineering, Lodz University of Technology, Wólczańska 215 street, 90–924 Łódź (Poland)

    2016-05-18

    The role of polymers as retarder additives is to prolong the workability connected with setting time of gypsum. Various cellulose derivatives, soluble in water in concentration up to 1,5% by weight were applied taking different water/binder ratio. The hydration process of calcium sulfate hemihydrate (gypsum binder) into dihydrate (gypsum plaster) was observed by setting and calorimetric techniques. Scanning electron microscopy confirmed that the gypsum microstructure was varied when polymers are used. The mechanical properties of gypsum plasters were studied by bending strength test and they are correlated with sample microstructure.

  7. Manufacture of Durable Stucco Gypsum in Outdoor Plastering Engineering%耐久型室外粉刷石膏的性能及微观结构

    Institute of Scientific and Technical Information of China (English)

    余红发; 丁向群

    2001-01-01

    研究白水泥等作激发剂的难溶性无水石膏的性能,并制备出用于室外条件下的耐久型粉刷石膏.用XRD和SEM-EDAX分析了耐久型粉刷石膏外墙饰面使用18年后的相组成和显微结构.%The properties of anhydrite [1 with white protland cement as accelerating agent are studied, and the durable stucco gypsum in outdoor condition are prepared successfully. The phase composition and microstructure of the durable stucco gypsum external veneer after 18 years' exposure are analyzed by XRD and SEM-EDAX.

  8. A Comparative Evaluation of Mixed Dentition Analysis on Reliability of Cone Beam Computed Tomography Image Compared to Plaster Model.

    Science.gov (United States)

    Gowd, Snigdha; Shankar, T; Dash, Samarendra; Sahoo, Nivedita; Chatterjee, Suravi; Mohanty, Pritam

    2017-01-01

    The aim of the study was to evaluate the reliability of cone beam computed tomography (CBCT) obtained image over plaster model for the assessment of mixed dentition analysis. Thirty CBCT-derived images and thirty plaster models were derived from the dental archives, and Moyer's and Tanaka-Johnston analyses were performed. The data obtained were interpreted and analyzed statistically using SPSS 10.0/PC (SPSS Inc., Chicago, IL, USA). Descriptive and analytical analysis along with Student's t-test was performed to qualitatively evaluate the data and P plaster model; the mean for Moyer's analysis in the left and right lower arch for CBCT and plaster model was 21.2 mm, 21.1 mm and 22.5 mm, 22.5 mm, respectively. CBCT-derived images were less reliable as compared to data obtained directly from plaster model for mixed dentition analysis.

  9. Index of Complexity, Outcome and Need scored on plaster and digital models.

    NARCIS (Netherlands)

    Veenema, A.C.; Katsaros, C.; Boxum, S.C.; Bronkhorst, E.M.; Kuijpers-Jagtman, A.M.

    2009-01-01

    The aim of this study was to compare standard plaster models with their digital counterparts for the applicability of the Index of Complexity, Outcome, and Need (ICON). Generated study models of 30 randomly selected patients: 30 pre- (T(0)) and 30 post- (T(1)) treatment. Two examiners, calibrated in

  10. Index of Complexity, Outcome and Need scored on plaster and digital models

    NARCIS (Netherlands)

    Veenema, A. C.; Katsaros, C.; Boxum, S. C.; Bronkhorst, E. M.; Kuijpers-Jagtman, A. M.

    2009-01-01

    The aim of this study was to compare standard plaster models with their digital counterparts for the applicability of the Index of Complexity, Outcome, and Need (ICON). Generated study models of 30 randomly selected patients: 30 pre- (T-0) and 30 post- (T-1) treatment. Two examiners, calibrated in t

  11. Accuracy and reproducibility of linear measurements of resin, plaster, digital and printed study-models.

    Science.gov (United States)

    Saleh, Waleed K; Ariffin, Emy; Sherriff, Martyn; Bister, Dirk

    2015-01-01

    To compare the accuracy and reproducibility of measurements of on-screen three-dimensional (3D) digital surface models captured by a 3Shape R700™ laser-scanner, with measurements made using a digital caliper on acrylic, plaster models or model replicas. Four sets of typodont models were used. Acrylic models, alginate impressions, plaster models and physical replicas were measured. The 3Shape R700™ laser-scanning device with 3Shape™ software was used for scans and measurements. Linear measurements were recorded for selected landmarks, on each of the physical models and on the 3D digital surface models on ten separate occasions by a single examiner. Comparing measurements taken on the physical models the mean difference of the measurements was 0.32 mm (SD 0.15 mm). For the different methods (physical versus digital) the mean difference was 0.112 mm (SD 0.15 mm). None of the values showed a statistically significant difference (p plaster and acrylic models. The comparison of measurements on the physical models showed no significant difference. The 3Shape R700™ is a reliable device for capturing surface details of models in a digital format. When comparing measurements taken manually and digitally there was no statistically significant difference. The Objet Eden 250™ 3D prints proved to be as accurate as the original acrylic, plaster, or alginate impressions as was shown by the accuracy of the measurements taken. This confirms that using virtual study models can be a reliable method, replacing traditional plaster models.

  12. Antihyperalgesic efficacy of 5% lidocaine medicated plaster in capsaicin and sunburn pain models--two randomized, double-blinded, placebo-controlled crossover trials in healthy volunteers.

    Science.gov (United States)

    Gustorff, Burkhard; Hauer, David; Thaler, Johannes; Seis, Astrid; Draxler, Julia

    2011-12-01

    The aim of this research is to analyze analgesic efficacy of the 5% lidocaine medicated plaster in two randomized, double-blinded, placebo-controlled, crossover studies in 16 healthy volunteers using capsaicin and sunburn pain models. Lidocaine and placebo plasters were simultaneously applied to forearms and thighs at contralateral body sites for three alternating 12-h plaster-on/plaster-off periods. Between the second and third plaster-on period, 4.2-cm circular spots on both pretreated thighs were irradiated with three times the individual minimal erythema dose of UVB light. After the last plaster-on period, 20 μl of 0.1% capsaicin was injected intradermally into both forearms. The study was repeated using a single 12-h plaster application. The area of pinprick hyperalgesia was diminished by 53% (p plaster effectively treats mechanical hyperalgesia and cold pain.

  13. Technical economical study of plaster production in a continuous rotate kiln using natural gas; Estudo tecnico-economico do processo de producao de gesso em forno rotativo continuo com uso de gas natural

    Energy Technology Data Exchange (ETDEWEB)

    Benachour, M. [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); Santos, Valdemir A. dos [Universidade Catolica de Pernambuco (UNICAP), Recife, PE (Brazil); Peres, Luciano dos S. [Instituto de Tecnologia de Pernambuco (ITEP), Recife, PE (Brazil); Campos, Michel F. [PETROBRAS, Rio de Janeiro, RJ (Brazil); Zimmerle, Sergio R.T.S. [Companhia Pernambucana de Gas - COPERGAS, Recife, PE (Brazil)

    2004-07-01

    At Araripe Gypsum Site, Pernambuco State, gypsum is dehydrated to produce plaster using wood and BPF oil as major fuels, which generate serious environmental impacts. Natural gas provides important advantages over conventional fuels. Using this gas improves the thermal efficiency of direct contact process, producing no contamination in final product, also reducing considerably environmental pollution levels. In this scope, a rotate kiln was designed in pilot scale, where was carried out gypsum dehydration tests to produce beta plaster using natural gas. In this work are presented mathematical models to simulate the axial profiles of the gypsum conversion and the gas and solid temperatures on the axial length of the kiln. The mathematical models are used as restrictions to obtention of the operational optimized conditions to a minimum gypsum conversion of the 85%. The simulation results were compared to experimental ones and were obtained a good agreement between both the values. (author)

  14. Comparison of virtual and manual tooth setups with digital and plaster models in extraction cases.

    Science.gov (United States)

    Im, Joon; Cha, Jung-Yul; Lee, Kee-Joon; Yu, Hyung-Seog; Hwang, Chung-Ju

    2014-04-01

    The aim of this study was to compare the virtual and manual tooth setups with digital and plaster models in extraction cases by measuring various occlusal parameters and applying the American Board of Orthodontics objective grading system. Linear intra-arch and interarch dimensions (arch width and length, perimeter, overjet, and overbite), angular variables (tip, torque, and rotation), and American Board of Orthodontics objective grading system scores obtained from a digital virtual setup model were compared with those from a plaster model setup. The digital virtual setup model resulted in smaller arch perimeters than did the plaster setup model by 2.20 mm in the maxillary arch (P overjet (P overjet, occlusal contact, and total score (P <0.01) were required for the digital than for the manual setup model. Digital and manual setups lead to similar measurements for intra-arch and interarch occlusal variables. However, because of the possibility of collision on proximal and occlusal contact, delicate adjustments in proximal and occlusal contacts are required. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  15. CNC机器人七轴加工石膏模型放大雕塑%CNC robot seven axis processing gypsum model enlarged sculpture

    Institute of Scientific and Technical Information of China (English)

    胡春良; 李斌

    2016-01-01

    CNC机器人七轴加工设备可实现复杂立体造型的自动化雕刻加工。简单介绍CNC机器人七轴加工石膏模型放大雕塑工艺流程。%CNC robots seven axis machining equipment is by an industrial robot arm control electric spindle, and multiple spindle automatic programming software and used to control the operation of a robotic arm software portfolio and, automatic carving processing of three-dimensional modeling of complex. Recent Chinese art casting enterprises from Italy introduced CNC robots for seven - axis machining sculpture magnifying plaster model of special equipment, realize the art casting another major leap of the large-scale sculpture lofting. This paper simply introduces the CNC robot seven axis processing gypsum model to enlarge the sculpture process.

  16. [PHYSICAL PROPERTIES OF PLASTER BANDAGES].

    Science.gov (United States)

    Antabak, Anko; Barisić, Branimir; Andabak, Matej; Bradić, Lucija; Brajcinović, Melita; Haramina, Tatjana; Haluzan, Damir; Fuchs, Nino; Durkovir, Selena; Curković, Selena; Luetić, Tomislav; Sisko, Jerko; Prlić, Ivica

    2015-01-01

    The physical properties of plaster bandages are a very important factor in achieving the basic functions of immobilization (maintaining bone fragments in the best possible position), which directly affects the speed and quality of fracture healing. This paper compares the differences between the physical properties of plaster bandages (mass, specific weight, drying rate, elasticity and strength) and records the differences in plaster modeling of fast bonding 10 cm wide plaster bandages, from three different manufacturers: Safix plus (Hartmann, Germany), Cellona (Lohman Rauscher, Austria) and Gipsan (Ivo Lola Ribar ltd., Croatia). Plaster tiles from ten layers of plaster, dimension 10 x 10 cm were made. The total number of tiles from each manufacturer was 48. The water temperature of 22 °C was used for the first 24 tiles and 34 'C was used for the remainder. The average specific weight of the original packaging was: Cellona (0.52 g/cm3), Gipsan (0.50 g/cm3), Safix plus (0.38 g/cm3). Three days after plaster tile modeling an average specific weight of the tiles was: Gipsan (1.15 g/cm3), Safix plus (1.00 g/cm3), Cellona (1.10 g/cm3). The average humidity of 50% for Safix plus and Cellona plaster tiles was recorded 18 hours after modeling, while for the Gipsan plaster tiles, this humidity value was seen after 48 hours. On the third day after plaster modeling the average humidity of the plaster tiles was 30% for Gipsan, 24% for Safix and 16% for Cellona. Cellona plaster tiles made with 34 °C water achieved the highest elasticity (11.75±3.18 MPa), and Gipsan plaster tiles made with 22 °C had the lowest (7.21±0.9 MPa). Cellona plaster tiles made with 34 °C water showed maximum material strength (4390±838 MPa), and Gipsan plaster tiles made with 22 °C water showed the lowest material strength (771±367 MPa). The rigidity and strength of Cellona and Gipsan plaster are higher in tiles made in warmer water, and for Safix plus are higher in tiles made in cooler water

  17. Adhesive plasters

    Science.gov (United States)

    Holcombe, Jr., Cressie E.; Swain, Ronald L.; Banker, John G.; Edwards, Charlene C.

    1978-01-01

    Adhesive plaster compositions are provided by treating particles of Y.sub.2 O.sub.3, Eu.sub.2 O.sub.3, Gd.sub.2 O.sub.3 or Nd.sub.2 O.sub.3 with dilute acid solutions. The resulting compositions have been found to spontaneously harden into rigid reticulated masses resembling plaster of Paris. Upon heating, the hardened material is decomposed into the oxide, yet retains the reticulated rigid structure.

  18. Plaster of Paris: the orthopaedic surgeon heritage.

    Science.gov (United States)

    Hernigou, Philippe

    2016-08-01

    Plastering is one of the most ancient of the building handicrafts. Plaster is the common name for calcium sulphate hemi hydrate made by heating the mineral gypsum, the common name for sulphate of lime. In the tenth century the Arabs used liquid plaster in orthopaedic treatment. At the beginning of the nineteenth century, patients with fractures of the lower extremities-and often of the upper extremities as well-were treated in bed with restriction of all activity for many weeks until the fractures united. It was the practice of surgeons to dress wounds and fractures at frequent intervals. The bandages, pads, and splints were removed, the fractures manipulated, and the dressings reapplied. The search for simpler, less cumbersome methods of treatment led to the development of occlusive dressings, stiffened at first with starch and later with plaster of Paris. The ambulatory treatment of fractures was the direct result of these innovations. Two military surgeons, Antonius Mathijsen of the Netherlands, and Nikolai Ivanovitch Pirogov of Russia, were responsible for the introduction of the new plaster bandage technique. At the beginning of the twentieth century the technique was improved by Jean-François Calot, a French surgeon, who invented the hand manufacture of plaster bandage as a roll. During the twentieth century, walking cast and ambulation for fresh fractures were developed with plaster and pin incorporated in plaster; the open fracture care concept was introduced with plaster of Paris by Trueta before the external fixation.

  19. Comparative study of dental arch width in plaster models, photocopies and digitized images

    Directory of Open Access Journals (Sweden)

    Maria Cristina Rosseto

    2009-06-01

    Full Text Available The aim of this study was to comparatively assess dental arch width, in the canine and molar regions, by means of direct measurements from plaster models, photocopies and digitized images of the models. The sample consisted of 130 pairs of plaster models, photocopies and digitized images of the models of white patients (n = 65, both genders, with Class I and Class II Division 1 malocclusions, treated by standard Edgewise mechanics and extraction of the four first premolars. Maxillary and mandibular intercanine and intermolar widths were measured by a calibrated examiner, prior to and after orthodontic treatment, using the three modes of reproduction of the dental arches. Dispersion of the data relative to pre- and posttreatment intra-arch linear measurements (mm was represented as box plots. The three measuring methods were compared by one-way ANOVA for repeated measurements (α = 0.05. Initial / final mean values varied as follows: 33.94 to 34.29 mm / 34.49 to 34.66 mm (maxillary intercanine width; 26.23 to 26.26 mm / 26.77 to 26.84 mm (mandibular intercanine width; 49.55 to 49.66 mm / 47.28 to 47.45 mm (maxillary intermolar width and 43.28 to 43.41 mm / 40.29 to 40.46 mm (mandibular intermolar width. There were no statistically significant differences between mean dental arch widths estimated by the three studied methods, prior to and after orthodontic treatment. It may be concluded that photocopies and digitized images of the plaster models provided reliable reproductions of the dental arches for obtaining transversal intra-arch measurements.

  20. Properties of type IV plaster considering variation in the mold/model position during setting stage

    Directory of Open Access Journals (Sweden)

    Tarcisio José de Arruda Paes Junior

    2010-04-01

    Full Text Available Objective: To assess the influence of the position of the mold during the setting stage of type IV stone plaster Durone (Dentsply Ind. Com., Rio de Janeiro, Brazil, on the following properties: surface hardness and roughness. Methods: For the roughness test, two groups (n=6 in the form of pellets were prepared. In the first group, the surface of the base of the device was turned down during the plaster setting stage (N, in the second group this position was inverted, which has been described as an act of capsize it (E. For analysis, a roughness meter with reading precision of 0.01 μm was used. With regard to the hardness analysis, two groups with conical-shaped samples were obtained. The plasters were left to set under the same conditions of the mold/model position described for the previous experiment. Hardness measurement was performed in a durometer with a spherical penetrating tip for Rockwell readout. Three measurements were performed for each test specimen in both tests. Results: The hardness (N - 39.8, standard deviation = 3.3, E - 30.8, standard deviation = 5.6 and roughness data (N - 0.67, standard deviation = 0.17, E - 0.74, standard deviation = 0.13 submitted to the Student’s-t test (5% showed no statistically significant differences for the roughness test (0.489, but showed statistically significant differences for the hardness test (0.014. Conclusion: The variation in the mold/model position influenced the final characteristics of the specimens in terms of hardness, since those obtained with the capsize technique showed lower surface hardness, whereas for roughness these differences were not statistically significant.

  1. Dental arch relationships on three-dimensional digital study models and conventional plaster study models for patients with unilateral cleft lip and palate.

    Science.gov (United States)

    Asquith, J A; McIntyre, G T

    2012-09-01

    To determine if three-dimensional (3D) digital study models could replace plaster study models for the evaluation of dental arch relationships for patients with unilateral cleft lip and palate. Observational study involving plaster study models from a records archive. U.K. National Health Service. Thirty sets of study models of 5-year-old patients with unilateral cleft lip and palate were identified and scanned to produce 3D digital study models by ESM Digital Solutions Ltd. (Swords, Co. Dublin, Ireland) using an R250 Orthodontic Study Model Scanner (3Shape A/S, Copenhagen, Denmark). None. The plaster and 3D digital study models were scored using the 5-year-olds' and modified Huddart Bodenham indices and analyzed using the Friedman test (p plaster and 3D digital models. Intra-observer and interobserver reproducibility were good (0.62 to 0.83 and 0.64 to 0.78, respectively). There were no statistically significant differences between the scores for the 3D digital study models when compared to the plaster study models for either the 5-year-olds' index (p  =  .12) or for the modified Huddart Bodenham index (p  =  .506). Three-dimensional digital models are a valid alternative to traditional plaster study models for the evaluation of dental arch relationships in patients with unilateral cleft lip and palate.

  2. Modeling grain size variations of aeolian gypsum deposits at White Sands, New Mexico, using AVIRIS imagery

    Science.gov (United States)

    Ghrefat, H.A.; Goodell, P.C.; Hubbard, B.E.; Langford, R.P.; Aldouri, R.E.

    2007-01-01

    Visible and Near-Infrared (VNIR) through Short Wavelength Infrared (SWIR) (0.4-2.5????m) AVIRIS data, along with laboratory spectral measurements and analyses of field samples, were used to characterize grain size variations in aeolian gypsum deposits across barchan-transverse, parabolic, and barchan dunes at White Sands, New Mexico, USA. All field samples contained a mineralogy of ?????100% gypsum. In order to document grain size variations at White Sands, surficial gypsum samples were collected along three Transects parallel to the prevailing downwind direction. Grain size analyses were carried out on the samples by sieving them into seven size fractions ranging from 45 to 621????m, which were subjected to spectral measurements. Absorption band depths of the size fractions were determined after applying an automated continuum-removal procedure to each spectrum. Then, the relationship between absorption band depth and gypsum size fraction was established using a linear regression. Three software processing steps were carried out to measure the grain size variations of gypsum in the Dune Area using AVIRIS data. AVIRIS mapping results, field work and laboratory analysis all show that the interdune areas have lower absorption band depth values and consist of finer grained gypsum deposits. In contrast, the dune crest areas have higher absorption band depth values and consist of coarser grained gypsum deposits. Based on laboratory estimates, a representative barchan-transverse dune (Transect 1) has a mean grain size of 1.16 ??{symbol} (449????m). The error bar results show that the error ranges from - 50 to + 50????m. Mean grain size for a representative parabolic dune (Transect 2) is 1.51 ??{symbol} (352????m), and 1.52 ??{symbol} (347????m) for a representative barchan dune (Transect 3). T-test results confirm that there are differences in the grain size distributions between barchan and parabolic dunes and between interdune and dune crest areas. The t-test results

  3. Assessing agreement in measurements of orthodontic study models: Digital caliper on plaster models vs 3-dimensional software on models scanned by structured-light scanner.

    Science.gov (United States)

    Wan Hassan, Wan Nurazreena; Othman, Siti Adibah; Chan, Chee Seng; Ahmad, Roshahida; Ali, Siti Nor'Ain; Abd Rohim, Anis

    2016-11-01

    In this study we aimed to compare measurements on plaster models using a digital caliper, and on 3-dimensional (3D) digital models, produced using a structured-light scanner, using 3D software. Fifty digital models were scanned from the same plaster models. Arch and tooth size measurements were made by 2 operators, twice. Calibration was done on 10 sets of models and checked using the Pearson correlation coefficient. Data were analyzed by error variances, repeatability coefficient, repeated-measures analysis of variance, and Bland-Altman plots. Error variances ranged between 0.001 and 0.044 mm for the digital caliper method, and between 0.002 and 0.054 mm for the 3D software method. Repeated-measures analysis of variance showed small but statistically significant differences (P plaster models and were, therefore, clinically acceptable. Copyright © 2016. Published by Elsevier Inc.

  4. Modelling of Fluidised Geomaterials: The Case of the Aberfan and the Gypsum Tailings Impoundment Flowslides

    Directory of Open Access Journals (Sweden)

    Paola Dutto

    2017-05-01

    Full Text Available The choice of a pure cohesive or a pure frictional viscoplastic model to represent the rheological behaviour of a flowslide is of paramount importance in order to obtain accurate results for real cases. The principal goal of the present work is to clarify the influence of the type of viscous model—pure cohesive versus pure frictional—with the numerical reproduction of two different real flowslides that occurred in 1966: the Aberfan flowslide and the Gypsum tailings impoundment flowslide. In the present work, a depth-integrated model based on the v - p w Biot–Zienkiewicz formulation, enhanced with a diffusion-like equation to account for the pore pressure evolution within the soil mass, is applied to both 1966 cases. For the Aberfan flowslide, a frictional viscous model based on Perzyna viscoplasticity is considered, while a pure cohesive viscous model (Bingham model is considered for the case of the Gypsum flowslide. The numerical approach followed is the SPH method, which has been enriched by adding a 1D finite difference grid to each SPH node in order to improve the description of the pore water evolution in the propagating mixture. The results obtained by the performed simulations are in agreement with the documentation obtained through the UK National Archive (Aberfan flowslide and the International Commission of large Dams (Gypsum flowslide.

  5. Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis.

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    Full Text Available Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models.Two types of dental models (intraoral scan and plaster model of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model.There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm.The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models.

  6. Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis.

    Science.gov (United States)

    Zhang, Fan; Suh, Kyung-Jin; Lee, Kyung-Min

    2016-01-01

    Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models. Two types of dental models (intraoral scan and plaster model) of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model. There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm. The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models.

  7. Numerical modelling and thermal simulation of PCM-gypsum composites with ESP-r

    Energy Technology Data Exchange (ETDEWEB)

    Heim, D.; Clarke, J.A. [Department of Building Physics and Building Materials, Technical University of Lodz, Lodz (Poland)

    2004-07-01

    The aim of the present work is to refine the ESP-r system by incorporating phase change materials (PCMs) modelling. The behaviour of PCMs is modelled using ESP-r's special materials facility. The effect of phase transition is added to the energy balance equation as a latent heat generation term according to the so-called effective heat capacity method. Numerical simulations were conducted for a multi-zone, highly glazed and naturally ventilated passive solar building. PCM-impregnated gypsum plasterboard was used as an internal room lining. The air, surface and resultant temperatures were compared with the no-PCM case and the diurnal latent heat storage effect was analysed. While this effect did not cause a considerable reduction in the diurnal temperature fluctuation, the PCMs did effectively store solar energy in the transitions periods. Additionally, the energy requirement at the beginning and end of the heating season was estimated and compared with ordinary gypsum wallboard. Within this comparison, the PCM composite solidification temperature was 22 {sup o}C (i.e. 2 K higher than the heating set-point for the room). The results show that solar energy stored in the PCM-gypsum panels can reduce the heating energy demand by up to 90% at times during the heating season. (author)

  8. Does the contact time of alginate with plaster cast influence its properties?

    Directory of Open Access Journals (Sweden)

    Mariana Marquezan

    2012-06-01

    Full Text Available The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups: Group 1 (G1 - with time of contact of 1 hour; and Group 2 (G2 - 12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan, respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA under a load of 100 gF for 15 s. The results showed significant difference (P £ 0.05 between groups in two of the three properties examined: surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.

  9. Does the contact time of alginate with plaster cast influence its properties?

    Directory of Open Access Journals (Sweden)

    Mariana Marquezan

    Full Text Available The aim of this study was to verify the influence of the time of contact between alginate and gypsum after the modeling procedure on the properties of the plaster cast, such as surface detail, dimensional stability and microhardness. Thirty cylindrical specimens of orthodontic gypsum Type III were made by means of impressions of a stainless steel master model which had five reference lines in the upper surface. The samples were divided into two groups: Group 1 (G1 - with time of contact of 1 hour; and Group 2 (G2 - 12 hours of contact. All the specimens were stored up to 48 hours until they underwent laboratory testing. Surface detail and dimensional stability were tested by one calibrated examiner using a visual analysis and a profilometer (Profile Projector Nikon model 6C, Nikon Corporation, Tokyo, Japan, respectively, to evaluate the quality of reproduction of the lines and the distances between them. The microhardness was determined for each sample by making six indentations with a Vickers diamond pyramid indenter (Buehler, Lake Bluff, USA under a load of 100 gF for 15 s. The results showed significant difference (P £ 0.05 between groups in two of the three properties examined: surface detail and microhardness, which decreased as the time of contact rose. The 12-hour time of contact between alginate and the plaster cast is not recommended because it influences the quality of the plaster cast.

  10. Measurements using orthodontic analysis software on digital models obtained by 3D scans of plaster casts : Intrarater reliability and validity.

    Science.gov (United States)

    Czarnota, Judith; Hey, Jeremias; Fuhrmann, Robert

    2016-01-01

    The purpose of this work was to determine the reliability and validity of measurements performed on digital models with a desktop scanner and analysis software in comparison with measurements performed manually on conventional plaster casts. A total of 20 pairs of plaster casts reflecting the intraoral conditions of 20 fully dentate individuals were digitized using a three-dimensional scanner (D700; 3Shape). A series of defined parameters were measured both on the resultant digital models with analysis software (Ortho Analyzer; 3Shape) and on the original plaster casts with a digital caliper (Digimatic CD-15DCX; Mitutoyo). Both measurement series were repeated twice and analyzed for intrarater reliability based on intraclass correlation coefficients (ICCs). The results from the digital models were evaluated for their validity against the casts by calculating mean-value differences and associated 95 % limits of agreement (Bland-Altman method). Statistically significant differences were identified via a paired t test. Significant differences were obtained for 16 of 24 tooth-width measurements, for 2 of 5 sites of contact-point displacement in the mandibular anterior segment, for overbite, for maxillary intermolar distance, for Little's irregularity index, and for the summation indices of maxillary and mandibular incisor width. Overall, however, both the mean differences between the results obtained on the digital models versus on the plaster casts and the dispersion ranges associated with these differences suggest that the deviations incurred by the digital measuring technique are not clinically significant. Digital models are adequately reproducible and valid to be employed for routine measurements in orthodontic practice.

  11. Computational modeling of latent-heat-storage in PCM modified interior plaster

    Science.gov (United States)

    Fořt, Jan; Maděra, Jiří; Trník, Anton; Pavlíková, Milena; Pavlík, Zbyšek

    2016-06-01

    The latent heat storage systems represent a promising way for decrease of buildings energy consumption with respect to the sustainable development principles of building industry. The presented paper is focused on the evaluation of the effect of PCM incorporation on thermal performance of cement-lime plasters. For basic characterization of the developed materials, matrix density, bulk density, and total open porosity are measured. Thermal conductivity is accessed by transient impulse method. DSC analysis is used for the identification of phase change temperature during the heating and cooling process. Using DSC data, the temperature dependent specific heat capacity is calculated. On the basis of the experiments performed, the supposed improvement of the energy efficiency of characteristic building envelope system where the designed plasters are likely to be used is evaluated by a computational analysis. Obtained experimental and computational results show a potential of PCM modified plasters for improvement of thermal stability of buildings and moderation of interior climate.

  12. Computational modeling of latent-heat-storage in PCM modified interior plaster

    Energy Technology Data Exchange (ETDEWEB)

    Fořt, Jan; Maděra, Jiří; Trník, Anton; Pavlíková, Milena; Pavlík, Zbyšek [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)

    2016-06-08

    The latent heat storage systems represent a promising way for decrease of buildings energy consumption with respect to the sustainable development principles of building industry. The presented paper is focused on the evaluation of the effect of PCM incorporation on thermal performance of cement-lime plasters. For basic characterization of the developed materials, matrix density, bulk density, and total open porosity are measured. Thermal conductivity is accessed by transient impulse method. DSC analysis is used for the identification of phase change temperature during the heating and cooling process. Using DSC data, the temperature dependent specific heat capacity is calculated. On the basis of the experiments performed, the supposed improvement of the energy efficiency of characteristic building envelope system where the designed plasters are likely to be used is evaluated by a computational analysis. Obtained experimental and computational results show a potential of PCM modified plasters for improvement of thermal stability of buildings and moderation of interior climate.

  13. Rapid prototyping of a complex model for the manufacture of plaster molds for slip casting ceramic

    Directory of Open Access Journals (Sweden)

    D. P. C. Velazco

    2014-12-01

    Full Text Available Computer assisted designing (CAD is well known for several decades and employed for ceramic manufacturing almost since the beginning, but usually employed in the first part of the projectual ideation processes, neither in the prototyping nor in the manufacturing stages. The rapid prototyping machines, also known as 3D printers, have the capacity to produce in a few hours real pieces using plastic materials of high resistance, with great precision and similarity with respect to the original, based on unprecedented digital models produced by means of modeling with specific design software or from the digitalization of existing parts using the so-called 3D scanners. The main objective of the work is to develop the methodology used in the entire process of building a part in ceramics from the interrelationship between traditional techniques and new technologies for the manufacture of prototypes. And to take advantage of the benefits that allow us this new reproduction technology. The experience was based on the generation of a complex piece, in digital format, which served as the model. A regular 15 cm icosahedron presented features complex enough not to advise the production of the model by means of the traditional techniques of ceramics (manual or mechanical. From this digital model, a plaster mold was made in the traditional way in order to slip cast clay based slurries, freely dried in air and fired and glazed in the traditional way. This experience has shown the working hypothesis and opens up the possibility of new lines of work to academic and technological levels that will be explored in the near future. This technology provides a wide range of options to address the formal aspect of a part to be performed for the field of design, architecture, industrial design, the traditional pottery, ceramic art, etc., which allow you to amplify the formal possibilities, save time and therefore costs when drafting the necessary and appropriate matrixes

  14. GyPSuM: A Detailed Tomographic Model of Mantle Density and Seismic Wave Speeds

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, N A; Forte, A M; Boschi, L; Grand, S P

    2010-03-30

    GyPSuM is a tomographic model fo mantle seismic shear wave (S) speeds, compressional wave (P) speeds and detailed density anomalies that drive mantle flow. the model is developed through simultaneous inversion of seismic body wave travel times (P and S) and geodynamic observations while considering realistic mineral physics parameters linking the relative behavior of mantle properties (wave speeds and density). Geodynamic observations include the (up to degree 16) global free-air gravity field, divergence of the tectonic plates, dynamic topography of the free surface, and the flow-induced excess ellipticity of the core-mantle boundary. GyPSuM is built with the philosophy that heterogeneity that most closely resembles thermal variations is the simplest possible solution. Models of the density field from Earth's free oscillations have provided great insight into the density configuration of the mantle; but are limited to very long-wavelength solutions. Alternatively, simply scaling higher resolution seismic images to density anomalies generates density fields that do not satisfy geodynamic observations. The current study provides detailed density structures in the mantle while directly satisfying geodynamic observations through a joint seismic-geodynamic inversion process. Notable density field observations include high-density piles at the base of the superplume structures, supporting the fundamental results of past normal mode studies. However, these features are more localized and lower amplitude than past studies would suggest. When we consider all seismic anomalies in GyPSuM, we find that P and S-wave speeds are strongly correlated throughout the mantle. However, correlations between the high-velocity S zones in the deep mantle ({approx} 2000 km depth) and corresponding P-wave anomalies are very low suggesting a systematic divergence from simplified thermal effects in ancient subducted slab anomalies. Nevertheless, they argue that temperature variations are

  15. Cost effectiveness of a lidocaine 5% medicated plaster compared with pregabalin for the treatment of postherpetic neuralgia in the UK: a Markov model analysis.

    Science.gov (United States)

    Ritchie, Mark; Liedgens, Hiltrud; Nuijten, Mark

    2010-01-01

    Published analyses have demonstrated that the lidocaine (lignocaine) plaster is a cost-effective treatment for postherpetic neuralgia (PHN) relative to gabapentin or pregabalin. However, these analyses have been based on indirect comparisons from placebo-controlled trials, and there is evidence of a discrepancy between the outcomes of direct and indirect analyses. Fortunately, recent publication of the results of a head-to-head trial comparing the lidocaine plaster and pregabalin in patients with PHN or diabetic polyneuropathy allows customization of the existing model to more accurately reflect the relative cost effectiveness of these two products. To assess the cost-effectiveness of the lidocaine 5% medicated plaster compared with pregabalin for the treatment of PHN in the UK primary-care setting. A Markov model has been developed to assess the costs and benefits of the lidocaine plaster and pregabalin over a 6-month time horizon for the treatment of patients with PHN who are intolerant to tricyclic antidepressants and in whom analgesics are ineffective or contraindicated. The model structure allows for differences in costs, utilities (derived from published data and from the head-to-head trial) and transition probabilities between the initial 30-day run-in period and maintenance therapy, and also takes account of add-in medication and drugs received by patients discontinuing therapy. The calculation was based on data from the recent head-to-head trial described above. Additional data sources included published literature, discussions with a Delphi panel, official price/tariff lists and national population statistics. The study was conducted from the perspective of the UK National Health Service (NHS). The base-case analysis (1.71 lidocaine plasters per day used in the head-to-head trial for the PHN population) indicated that the total cost of treating PHN patients for 6 months with the lidocaine plaster was pound 980 per patient treated, compared with pound 784

  16. Accuracy of Bolton analysis measured in laser scanned digital models compared with plaster models (gold standard) and cone-beam computer tomography images.

    Science.gov (United States)

    Kim, Jooseong; Lagravére, Manuel O

    2016-01-01

    The aim of this study was to compare the accuracy of Bolton analysis obtained from digital models scanned with the Ortho Insight three-dimensional (3D) laser scanner system to those obtained from cone-beam computed tomography (CBCT) images and traditional plaster models. CBCT scans and plaster models were obtained from 50 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner; Bolton ratios were calculated with its software. CBCT scans were imported and analyzed using AVIZO software. Plaster models were measured with a digital caliper. Data were analyzed with descriptive statistics and the intraclass correlation coefficient (ICC). Anterior and overall Bolton ratios obtained by the three different modalities exhibited excellent agreement (> 0.970). The mean differences between the scanned digital models and physical models and between the CBCT images and scanned digital models for overall Bolton ratios were 0.41 ± 0.305% and 0.45 ± 0.456%, respectively; for anterior Bolton ratios, 0.59 ± 0.520% and 1.01 ± 0.780%, respectively. ICC results showed that intraexaminer error reliability was generally excellent (> 0.858 for all three diagnostic modalities), with < 1.45% discrepancy in the Bolton analysis. Laser scanned digital models are highly accurate compared to physical models and CBCT scans for assessing the spatial relationships of dental arches for orthodontic diagnosis.

  17. Intra-arch dimensional measurement validity of laser-scanned digital dental models compared with the original plaster models: a systematic review.

    Science.gov (United States)

    De Luca Canto, G; Pachêco-Pereira, C; Lagravere, M O; Flores-Mir, C; Major, P W

    2015-05-01

    A systematic review was undertaken to evaluate the validity of intra-arch dimensional measurements made from laser-scanned digital dental models in comparison with measurements directly obtained from the original plaster casts (gold standard). Finally included articles were only those reporting studies that compared measurements from digital models produced from laser scanning against their plaster models. Measurements from the original plaster models should have been made using a manual or digital caliper (gold standard). Articles that used scans from impressions or digital photographs were discarded. Detailed individual search strategies for Cochrane, EMBASE, MEDLINE, PubMed, and LILACS were developed. The references cited in the selected articles were also checked for any references that could have been missed in the electronic database searches. A partial gray literature search was undertaken using Google Scholar. The methodology of selected studies was evaluated using the 14-item quality assessment tool for diagnostic accuracy studies (QUADAS). Only 16 studies were finally included for the qualitative/quantitative synthesis. The selected studies consistently agree that the validity of measurements obtained after using a laser scanner from plaster models is similar to direct measurements. Any stated differences would be unlikely clinically relevant. There is consistent scientific evidence to support the validity of measurements from digital dental models in comparison with intra-arch dimensional measurements directly obtained from them. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. 三种消毒方法对石膏模型压缩强度的影响%INFLUENCES OF THREE KINDS OF DISINFECTION METHODS ON COMPRESSIVE STRENGTH OF GYPSUM MODELS

    Institute of Scientific and Technical Information of China (English)

    吴世莲; 陆林侦; 曹明国; 查光玉

    2011-01-01

    Objective To study the influences of three kinds of disinfection methods on compressive strength of oral gypsum models. Methods On physical multi - function experimental bench the compressive strength of oral gypsum models was tested after microwave disinfection, pressure steam sterilization and ultraviolet irradiation disinfection. Results The compressive strength of three kinds of gypsum models including plaster, dental stone, high strength dental stone treated by microwave disinfection was slightly lower than that of the control group, but the difference had no statistical significance (P > 0.05). In addition to the gypsum models of high strength dental stone, the compressive strength of the other two kinds of gypsum models treated by ultraviolet irradiation disinfection was slightly lower too. The compressive strength of three kinds of gypsum models treated by pressure steam sterilization was significantly lower than that of the control group. Differences between the two groups of data were statistically significant (P < 0. 01). Conclusion Disinfection by microwave heating and ultraviolet irradiation do not obviously affect the compressive strength of oral gypsum models, but disinfection by pressure steam sterilization obviously affect the compressive strength of oral gypsum models.%目的 研究三种消毒方法对口腔石膏模型压缩强度的影响.方法 采用物理多功能试验台,对微波消毒法、压力蒸汽灭菌法和紫外线照射法消毒后的口腔石膏模型压缩强度进行了测试.结果 微波消毒法处理后的熟石膏、硬石膏和超硬石膏模型等种类石膏模型的压缩强度均略低于对照组压缩强度,但两组数据差异没有显著统计学意义(p>0.05);紫外线照射消毒法除超硬石膏模型之外,对另两种模型压缩强度也略有降低.压力蒸汽灭菌处理后的三种石膏模型的压缩强度明显低于对照,两组数据比较差异有显著统计学意义(p<0.01).结论 微

  19. Calibration of a hysteretic model for glass fiber reinforced gypsum wall panels

    Science.gov (United States)

    Janardhana, Maganti; Robin Davis, P.; Ravichandran, S. S.; Prasad, A. M.; Menon, D.

    2014-06-01

    Glass fiber reinforced gypsum (GFRG) wall panels are prefabricated panels with hollow cores, originally developed in Australia and subsequently adopted by India and China for use in buildings. This paper discusses identification and calibration of a suitable hysteretic model for GFRG wall panels filled with reinforced concrete. As considerable pinching was observed in the experimental results, a suitable hysteretic model with pinched hysteretic rule is used to conduct a series of quasi-static as inelastic hysteretic response analyses of GFRG panels with two different widths. The calibration of the pinching model parameters was carried out to approximately match the simulated and experimental responses up to 80% of the peak load in the post peak region. Interestingly, the same values of various parameters (energy dissipation and pinching related parameters) were obtained for all five test specimens.

  20. Linear dimensional changes in plaster die models using different elastomeric materials

    Directory of Open Access Journals (Sweden)

    Jefferson Ricardo Pereira

    2010-09-01

    Full Text Available Dental impression is an important step in the preparation of prostheses since it provides the reproduction of anatomic and surface details of teeth and adjacent structures. The objective of this study was to evaluate the linear dimensional alterations in gypsum dies obtained with different elastomeric materials, using a resin coping impression technique with individual shells. A master cast made of stainless steel with fixed prosthesis characteristics with two prepared abutment teeth was used to obtain the impressions. References points (A, B, C, D, E and F were recorded on the occlusal and buccal surfaces of abutments to register the distances. The impressions were obtained using the following materials: polyether, mercaptan-polysulfide, addition silicone, and condensation silicone. The transfer impressions were made with custom trays and an irreversible hydrocolloid material and were poured with type IV gypsum. The distances between identified points in gypsum dies were measured using an optical microscope and the results were statistically analyzed by ANOVA (p < 0.05 and Tukey's test. The mean of the distances were registered as follows: addition silicone (AB = 13.6 µm, CD=15.0 µm, EF = 14.6 µm, GH=15.2 µm, mercaptan-polysulfide (AB = 36.0 µm, CD = 36.0 µm, EF = 39.6 µm, GH = 40.6 µm, polyether (AB = 35.2 µm, CD = 35.6 µm, EF = 39.4 µm, GH = 41.4 µm and condensation silicone (AB = 69.2 µm, CD = 71.0 µm, EF = 80.6 µm, GH = 81.2 µm. All of the measurements found in gypsum dies were compared to those of a master cast. The results demonstrated that the addition silicone provides the best stability of the compounds tested, followed by polyether, polysulfide and condensation silicone. No statistical differences were obtained between polyether and mercaptan-polysulfide materials.

  1. Effects of Panax ginseng-containing herbal plasters on compressed intervertebral discs in an in vivo rat tail model

    Directory of Open Access Journals (Sweden)

    Chow Daniel H K

    2013-02-01

    Full Text Available Abstract Background Tienchi (Panax notoginseng has been used in conservative treatments for back pain as a major ingredient of many herbal medicines. This study aims to investigate the effects of a herbal medicine containing tienchi on compressed intervertebral discs in rats. Methods Using an in vivo rat tail model, intervertebral disc compression was simulated in the caudal 8–9 discs of 25 rats by continuous static compression (11 N for 2 weeks. An herbal medicine plaster (in which the major ingredient was tienchi was externally applied to the compressed disc (n=9 for three weeks, and held in place by an adhesive bandage, in animals in the Chinese Medicine (CM group. The effect of the bandage was evaluated in a separate placebo group (n=9, while no intervention with unrestricted motion was provided to rats in an additional control group (n=7. Disc structural properties were quantified by in vivo disc height measurement and in vitro morphological analysis. Results Disc height decreased after the application of compression (P P = 0.006 and placebo (P = 0.003 groups, but was maintained in the CM group (P = 0.494. No obvious differences in disc morphology were observed among the three groups (P = 0.896. Conclusion The tienchi-containing herbal plaster had no significant effect on the morphology of compressed discs, but maintained disc height in rats.

  2. Development of materials that cover the deposits of gypsum exploited in the polo plasterer in Pernambuco; Aproveitamento dos materiais que recobrem as jazidas de gipsita explotadas no polo gesseiro de Pernambuco

    Energy Technology Data Exchange (ETDEWEB)

    Rego, S.A.B.C.; Moraes, A.S. de; Anjos, I.F. dos, E-mail: sheila.abc.rego@hotmail.com [Universidade Federal de Pernambuco (UFPE), PE (Brazil); Lira, B.B. [Universidade Federal da Paraiba (UFPB), PB (Brazil)

    2012-07-01

    The mineral clay found on the surface of gypsum deposits in the region of Recife - PE are considered mining tailings and job search reference in new industrial applications for these minerals, ores. In this context, we performed the characterization of these materials with the purpose of its use as inorganic pigments in the ceramic coating. These minerals present 'in locus' different colors ranging from beige to reddish. After heat treatment at 1000° C their colors have varied tones that can be used as natural pigments in the ceramic industry. The techniques of fluorescence X-ray diffraction X-ray, infrared and colorimetry were applied in the characterization of mineral-ore in question. Using mineral processing techniques we obtain a physical separation of clay minerals associated. The use of concentrated after processing showed that the material has the potential to replace traditional pigments used in ceramic industry, and thus represent a new alternative on the market of natural pigments. Another potential comprehensive analysis of the material is its use associated with polymers in order to develop new materials. (author)

  3. Virtualizing ancient Rome: 3D acquisition and modeling of a large plaster-of-Paris model of imperial Rome

    Science.gov (United States)

    Guidi, Gabriele; Frischer, Bernard; De Simone, Monica; Cioci, Andrea; Spinetti, Alessandro; Carosso, Luca; Micoli, Laura L.; Russo, Michele; Grasso, Tommaso

    2005-01-01

    Computer modeling through digital range images has been used for many applications, including 3D modeling of objects belonging to our cultural heritage. The scales involved range from small objects (e.g. pottery), to middle-sized works of art (statues, architectural decorations), up to very large structures (architectural and archaeological monuments). For any of these applications, suitable sensors and methodologies have been explored by different authors. The object to be modeled within this project is the "Plastico di Roma antica," a large plaster-of-Paris model of imperial Rome (16x17 meters) created in the last century. Its overall size therefore demands an acquisition approach typical of large structures, but it also is characterized extremely tiny details typical of small objects (houses are a few centimeters high; their doors, windows, etc. are smaller than 1 centimeter). This paper gives an account of the procedures followed for solving this "contradiction" and describes how a huge 3D model was acquired and generated by using a special metrology Laser Radar. The procedures for reorienting in a single reference system the huge point clouds obtained after each acquisition phase, thanks to the measurement of fixed redundant references, are described. The data set was split in smaller sub-areas 2 x 2 meters each for purposes of mesh editing. This subdivision was necessary owing to the huge number of points in each individual scan (50-60 millions). The final merge of the edited parts made it possible to create a single mesh. All these processes were made with software specifically designed for this project since no commercial package could be found that was suitable for managing such a large number of points. Preliminary models are presented. Finally, the significance of the project is discussed in terms of the overall project known as "Rome Reborn," of which the present acquisition is an important component.

  4. 微波消毒口腔石膏模型的实验研究%EXPERIMENTAL STUDY ON MICROWAVE DISINFECTION OF CLINICAL PLASTER MODEL

    Institute of Scientific and Technical Information of China (English)

    郝玉梅; 肖瑞森; 张莹; 韩泽民

    2012-01-01

    Objective To evaluate of microwave disinfection effect for clinical plaster model. Methods Bacterial quantitative detection and fluorescence quantitative gene amplification technology were used to evaluate the disinfection efficacy of microwave irradiation for plaster model. Results The output power of microwave oven irradiation was 120W. After exposed for 5 min, Bacillus subtilis spores contaminated on the plaster model can be completely killed, and Hepatitis B virus DNA contamination in dental plaster model can be completely inactivated. Conclusion The common household microwave oven in full power conditions irradiate for 5 min, can effectively kill bacteria and virus polluted on the oral cavity plaster model.%目的 评价微波消毒法对口腔石膏模型的消毒效果.方法 用细菌定量检测和基因扩增荧光定量技术,对微波照射消毒口腔石膏模型的效果进行了观察.结果 用输出功率120 W微波炉对染菌口腔石膏模型进行照射消毒.照射5 min,可完全杀灭污染在口腔石膏模型上的枯草芽孢杆菌,并可完全灭活污染在口腔石膏模型上的乙型肝炎病毒DNA.结论 普通家用微波炉在满功率条件下照射5min,可有效杀灭污染在口腔石膏模型上的细菌和病毒.

  5. Shaking table model test and engineering practice of a new gypsum-adobe walls dwelling in Xinjiang autonomous region, China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Tie-gang; HU Xin; YU Chang-xia

    2008-01-01

    The paper introduces a new type of green building which suits for the construction of rural dwellings in Xinjiang, China. Results of the shaking table test on building model show that the single-layer gypsum-adobe structure has better seismic performance. And it also analyzes the construction features and engineering practice, which means that it is significant to extend this type of building to the drier regions in China.

  6. Urban mining : Recycling gypsum waste in Vancouver

    Energy Technology Data Exchange (ETDEWEB)

    McCamley, J.A. [New West Gypsum Recycling Inc., Vancouver, BC (Canada)

    2003-07-01

    Wallboard manufacturing, construction and deconstruction activities in North America, Europe and Japan result in large amounts of gypsum scrap, which creates an environmental problem. Disposing of this gypsum scrap in landfills often leads to hydrogen sulfide emissions and metallic sulfide groundwater leachates. Europe has dealt with the problem by enacting legislation that will come into effect in July 2005. The legislation is designed to strongly encourage gypsum recycling throughout entire jurisdictions. It is estimated that approximately 10 to 17 per cent of all gypsum used in the wallboard industry ends up as gypsum scrap. In North America, it represents almost one per cent of total waste. Each year in the United States, between 2.5 and 4.5 million tonnes of gypsum scrap are generated, with numbers very similar to Europe (the higher use of brick and concrete in Europe reduces the percentage of total tonnage). Gypsum has been banned from the landfills of British Columbia's Greater Vancouver region, forcing the recycling of all gypsum scrap. Large quantities of gypsum scrap are processed by New West Recycling, a Canadian firm using proprietary technology. This process leads to the re-incorporation of scrap gypsum into new wallboard, with the percentages sometimes reaching as high as 25 per cent. A case study of New West Recycling Inc., located in Langley, British Columbia was presented and recommendations were made concerning how other urban regions can implement gypsum scrap recycling programs modeled after this one. 6 refs.

  7. Grindability, Grading and Wettability of Recycled Plaster

    Institute of Scientific and Technical Information of China (English)

    李志新; 彭家惠; 赵海鑫; 邱星星; 赵敏

    2016-01-01

    The changes of grindability, grading and wettability of recycled plaster(R-P)and the mechanisms of these changes were studied by using vickers hardness, particle size distribution(PSD), scanning electron micro-scope(SEM) and nitrogen adsorption porosimetry to reveal that R-P was obviously different from plaster of Paris(POP). At the same milling time, R-P had the characteristics of high specific surface area, fine particle diame-ter and uneven size distribution compared with POP, so R-P possessed both good grindability and poor grading. The water absorption, dissolution rate and mass loss in dry-wet cycle of the hardened recycled gypsum(hardened RG) increased, while the water saturated strength and dry-wet cycle strength decreased significantly compared with the hardened virgin gypsum(hardened VG). Therefore, poor wettability could be seen in R-P. The analyses indi-cated that the changes of grindability and grading could be attributed to the reduction in hardness and the increase in the porosity of hardened RG and that the poor wettability of R-P was caused by the increase of large pores and the changes of microstructure of hardened RG.

  8. Plaster core washout tool

    Science.gov (United States)

    Heisman, R. M.; Keir, A. R.; Teramura, K.

    1977-01-01

    Tool powered by pressurized water or air removes water soluble plaster lining from Kevlar/epoxy duct. Rotating plastic cutterhead with sealed end fitting connects flexible shaft that allows tool to be used with curved ducts.

  9. Estimating mineral abundances of clay and gypsum mixtures using radiative transfer models applied to visible-near infrared reflectance spectra

    Science.gov (United States)

    Robertson, K. M.; Milliken, R. E.; Li, S.

    2016-10-01

    Quantitative mineral abundances of lab derived clay-gypsum mixtures were estimated using a revised Hapke VIS-NIR and Shkuratov radiative transfer model. Montmorillonite-gypsum mixtures were used to test the effectiveness of the model in distinguishing between subtle differences in minor absorption features that are diagnostic of mineralogy in the presence of strong H2O absorptions that are not always diagnostic of distinct phases or mineral abundance. The optical constants (k-values) for both endmembers were determined from bi-directional reflectance spectra measured in RELAB as well as on an ASD FieldSpec3 in a controlled laboratory setting. Multiple size fractions were measured in order to derive a single k-value from optimization of the optical path length in the radiative transfer models. It is shown that with careful experimental conditions, optical constants can be accurately determined from powdered samples using a field spectrometer, consistent with previous studies. Variability in the montmorillonite hydration level increased the uncertainties in the derived k-values, but estimated modal abundances for the mixtures were still within 5% of the measured values. Results suggest that the Hapke model works well in distinguishing between hydrated phases that have overlapping H2O absorptions and it is able to detect gypsum and montmorillonite in these simple mixtures where they are present at levels of ∼10%. Care must be taken however to derive k-values from a sample with appropriate H2O content relative to the modeled spectra. These initial results are promising for the potential quantitative analysis of orbital remote sensing data of hydrated minerals, including more complex clay and sulfate assemblages such as mudstones examined by the Curiosity rover in Gale crater.

  10. Arsenic uptake by gypsum and calcite: Modeling and probing by neutron and x-ray scattering

    CERN Document Server

    Fernandez-Martinez, Alejandro; Roman-Ross, Gabriela; Johnson, Mark R; Bardelli, Fabrizio; Turrillas, Xavier; Charlet, Laurent

    2006-01-01

    Here we report on two structural studies performed on As-doped gypsum (CaSO4 2H2O) and calcite (CaCO3), using neutron (D20-ILL) and x-ray (ID11-ESRF) diffraction data and EXAFS (BM8-ESRF). The aim of this study is to determine whether As gets into the bulk of gypsum and calcite structures or is simply adsorbed on the surface. Different mechanisms of substitution are used as hypotheses. The combined Rietveld analysis of neutron and x-ray diffraction data shows an expansion of the unit cell volume proportional to the As concentration within the samples. DFT-based simulations confirm the increase of the unit cell volume proportional to the amount of carbonate or sulphate groups substituted. Interpolation of the experimental Rietveld data allows us to distinguish As substituted within the structure from that adsorbed on the surface of both minerals.

  11. Research of gypsum binder of phosphogypsum and dry mortar on its basis

    OpenAIRE

    Казимагомедов, Ибрагим Эмирчубанович; Дехтярюк, Ольга Игоревна

    2015-01-01

    Gypsum binder was received by the method of intensive dehydration and the influence of admixture in phosphogypsum on the hydration process of gypsum binder was researched. Phase composition of phosphogypsum before and after calcination, using XFA, IR-spectroscopy and crystal optic analysis was defined. Dry mortar for plaster of interior walls of buildings on the basis of CaSO4·0,5H2O obtained from phosphogypsum is investigated. Its advantages and physical and chemical characteristics are shown

  12. Plaster-Wrap Dragons

    Science.gov (United States)

    Vance, Shelly

    2012-01-01

    In this article, the author describes how her students constructed a three-dimensional sculpture of a dragon using plaster wrap and other materials. The dragons were formed from modest means--using only a toilet-paper tube, newsprint, tape and wire.

  13. Plaster-Wrap Dragons

    Science.gov (United States)

    Vance, Shelly

    2012-01-01

    In this article, the author describes how her students constructed a three-dimensional sculpture of a dragon using plaster wrap and other materials. The dragons were formed from modest means--using only a toilet-paper tube, newsprint, tape and wire.

  14. Plaster, Portraits and Pots.

    Science.gov (United States)

    Schimsky, Marc

    1982-01-01

    Describes an art activity in which junior high school students make portrait pots using plaster casts and clay. Each student created a reflection of his or her personality in clay. Specific teaching methods and ways of working with materials are discussed. (AM)

  15. Use of waste gypsum to replace natural gypsum as set retarders in portland cement.

    Science.gov (United States)

    Chandara, Chea; Azizli, Khairun Azizi Mohd; Ahmad, Zainal Arifin; Sakai, Etsuo

    2009-05-01

    The present study is focused on clarifying the influence of waste gypsum (WG) in replacing natural gypsum (NG) in the production of ordinary Portland cement (OPC). WG taken from slip casting moulds in a ceramic factory was formed from the hydration of plaster of paris. Clinker and 3-5wt% of WG was ground in a laboratory ball mill to produce cement waste gypsum (CMWG). The same procedure was repeated with NG to substitute WG to prepare cement natural gypsum (CMNG). The properties of NG and WG were investigated via X-ray Diffraction (XRD), X-ray fluorescence (XRF) and differential scanning calorimetry (DSC)/thermogravimetric (TG) to evaluate the properties of CMNG and CMWG. The mechanical properties of cement were tested in terms of setting time, flexural and compressive strength. The XRD result of NG revealed the presence of dihydrate while WG contained dihydrate and hemihydrate. The content of dihydrate and hemihydrates were obtained via DSC/TG, and the results showed that WG and NG contained 12.45% and 1.61% of hemihydrate, respectively. Furthermore, CMWG was found to set faster than CMNG, an average of 15.29% and 13.67% faster for the initial and final setting times, respectively. This was due to the presence of hemihydrate in WG. However, the values obtained for flexural and compressive strength were relatively the same for CMNG and CMWG. Therefore, this result provides evidence that WG can be used as an alternative material to NG in the production of OPC.

  16. Primers role in plastering systems on concrete surfaces

    Science.gov (United States)

    Fischer, H. B.

    2015-01-01

    A drastic reduction in time frames between the manufacturing process of concrete units and the rendering phase (including prior priming) does not allow the concrete to dry well. This fact is also underlined by changes in concrete technology (denser concrete and denser concrete surfaces). The tests showed that the reduction of drying time (storage time) had a significant influence on the bonding properties of gypsum plaster on concrete surfaces. In such cases it is absolutely necessary to use an appropriate primer no matter what the processing temperature (2 °C to 20 °C) might be. In this publication the varying primer quality is shown.

  17. Comparative evaluation of feldespatic crowns fitness made from additional silicon impression and gypsum cast by CAD/CAM

    Directory of Open Access Journals (Sweden)

    Faramarz Zakavi

    2015-05-01

    Full Text Available Background and Aims: Marginal fit is one of the key factors in the success of fixed restoration. The aim of this study was to evaluate the fitness of feldespatic crowns made from additional silicon impression and gypsum cast by CAD/CAM.   Materials and Methods: 10 intact extracted upper premolar teeth were used for this experimental study. After preparation of the mounted teeth with radial shoulder finish line, 2 Vita Mark II feldespatic CAD/CAM machined crowns were fabricated for each tooth (one from scanning the additional silicone impression of the prepared tooth and the other one from the plaster model. Marginal gap of each crown was measured using SEM in two points on the mesial and 2 points on the buccal surface. Data were analyzed using Paired t-test with SPSS version 17 software (P<0.05.   Results: The mean of marginal gaps in crowns fabricated from additional silicone and model plaster were (155.13±37.11 and (130.18±12.35, respectively. However, no significant difference emerged between marginal gaps of the two methods (P=0.055. Also, the mean of marginal gaps in crowns fabricated from additional silicone and model plaster was higher in mesial (157.82±44.41 compared to buccal (127.50±24.26 region (P=0.003.   Conclusion: Marginal fit was not significantly differen ce between crown s made of the plaster casts and silicone molds and both methods showed the same results .

  18. Lethal Necrotizing Fasciitis Triggered by Plaster: Case Report and Review of Literature.

    Science.gov (United States)

    Jain, Mohit J; Mavani, Kinjal

    2016-01-01

    Plasters have been frequently associated with known complications such as infection, and compartment syndrome or deep vein thrombosis. However, life-threatening complication of necrotizing fasciitis (NF) has not been frequently attributed to plaster. We had a case of a 62-year male developing a lethal NF triggered by a below knee plaster for undisplaced fracture medial malleolus after twisting injury. He had no history suggestive of diabetes, renal impairment, and predisposing allergic factors or any comorbidity. Despite early diagnosis and aggressive management with above knee amputation, death occurs due to septic shock on the 20(th) day. A similar case of reported lethal NF triggered by plaster has also been reviewed in this report. This case highlights a life-threatening rare complication of plaster and author recommends thorough clinical history taking, precleaning of limb, use of sterile water and use of adequate wrap around skin for gypsum plasters as prevention apart from high index of suspicion for early diagnosis, and rapid management.

  19. [The antalgic and antiphiogistic function and mechanism of RGDT plaster].

    Science.gov (United States)

    Liu, Xiao-Xia; Wang, Zhi-wang; Chien, Xiao-pin; Liu, Cai-min; Tuo, Hai-yan

    2015-09-01

    To study the antalgic and antiphlogistic functions and mechanism of ronggudingtong (RGDT) plaster (traditional Chinese medicine). The painful models were established with hot plate test or acetic acid writhing and the inflammatory models were established with daubing dimethylbenzene on auricle or injecting formaldehyde in toe or synovial envelope to study the antalgic and antiphlogistic functions of RGDT Plaster. The total protein and leukotriene B4(LTB4) in inflammatory exudate were detected to investigate the antalgic and antiphlogistic mechanism of RGDT plaster. The mice were randomly divided into different groups (n = 11), on the basis of drug using, the indexes of pain threshold, swelling degree were observed. Sixty-six mice were used to establish gasbag synovitis model and randomly divided into normal control group,model control group, positive control group (Voltaren gel 0.8 mg/d)and low/medium/high dosage RGDT plaster treating groups(30 mg/d, 60 mg/d, 120 mg/d). 30 mg/d, 60 mg/d,120 mg/d RGDT plaster could upgrade the pain thresholds, remit auricular and foot swelling (P plaster has some antalgic and antiphlogistic functions, and one of the mechanisms is depressing synthesis of LTB4.

  20. Use of Deep Peat-Processing Products for Hydrophobic Modification of Gypsum Binder

    Directory of Open Access Journals (Sweden)

    Misnikov Oleg

    2017-01-01

    Full Text Available The article deals with the issue of gypsum binder quality reduction during its storage and transportation. The study provides the main methods to protect gypsum from unauthorized exposure to moisture and water vapor. The author proposes hydrophobic modification as a perspective method for the preservation of gypsum activity and its water absorption reduction. The substantiation of cement hydrophobization with the bitumen released during peat thermolysis is provided. The author proposes to use this method in the technology of gypsum binder production. The basic idea is to combine the hydrophobization process with the calcination of calcium sulfate dehydrate. This is facilitated by temperature ranges used for dehydration of natural gypsum and the initial stage of thermal decomposition of the organic matter of peat. The author defined experimentally an optimal concentration of the organic component in gypsum binder. After adding 0.5-1% of the peat additive, the gypsum plaster preserved its grade strength and increased its storage time without caking and hydration, also under adverse conditions. The proposed method is adapted to the technological processes presently used in the production and doesn’t require changing any equipment. The price of mineral raw materials and semi-finished products of peat are approximately equal which reduces the probability of increasing of the cost of hydrophobically modified gypsum binder.

  1. Exothermic properties of plaster-synthetic composite casts.

    Science.gov (United States)

    Burghardt, Rolf D; Anderson, John G; Reed, Rob A; Herzenberg, John E

    2014-03-01

    Plaster casts can cause burns. Synthetic casts do not. Composite plaster-synthetic casts have not been thoroughly evaluated. This study analyzed the temperature from plaster casts compared with composite casts in a variety of in vitro conditions that would simulate clinical practice. A Pyrex cylinder filled with constant body temperature circulating water simulated a human extremity. Circumferential casts, of either plaster or composite construction (plaster inner layer with outer synthetic layer), were applied to the model. Peak temperatures generated by the exothermic reactions were studied relative to the following variables: dip water temperature (24 °C versus 40 °C), cast thickness (16, 30, and 34 ply), and delayed (5-min) versus immediate application of the synthetic outer layers. Peak temperatures from the all-plaster casts were compared with the composite casts of the same thickness. Finally, the relative cast strength was determined. Potentially dangerous high temperatures were measured only when 40 °C dip water was used or when thick (30- or 34-ply) casts were made. Cast strength increased with increasing cast thickness. However, the presence of synthetics in the composite casts layers did not increase cast strength in every case. When applying composite casts, the outer synthetic layers should be applied several minutes after the plaster to minimize temperature rise. Composite casts do not routinely generate peak temperatures higher than plaster casts of similar thickness. Because the skin of children and the elderly is more temperature-sensitive than average adult skin, extra care should be taken to limit the exothermic reaction when casting children and the elderly: clean, room temperature dip water, minimal required cast thickness, avoidance of insulating pillows/blankets while the cast is drying.

  2. Gypsum karst in Great Britain

    Directory of Open Access Journals (Sweden)

    Cooper A.H.

    1996-01-01

    Full Text Available In Great Britain the most spectacular gypsum karst development is in the Zechstein gypsum (late Permian mainly in north-eastern England. The Midlands of England also has some karst developed in the Triassic gypsum in the vicinity of Nottingham. Along the north-east coast, south of Sunderland, well-developed palaeokarst, with magnificent breccia pipes, was produced by dissolution of Permian gypsum. In north-west England a small gypsum cave system of phreatic origin has been surveyed and recorded. A large actively evolving phreatic gypsum cave system has been postulated beneath the Ripon area on the basis of studies of subsidence and boreholes. The rate of gypsum dissolution here, and the associated collapse lead to difficult civil engineering and construction conditions, which can also be aggravated by water abstraction.

  3. Heat storage in gypsum. Final report to the Energy Agency; Vaermelagring i Gips. Slutrapport foer Energimyndigheten

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, Punya (Process Improvements, Plankgatan 26, Norrkoeping (Sweden)); Kindh, Torgny (Environnet AB, Norrkoeping (Sweden)); Lawrence, David; Wahlstroem, Krister (Dept. of Physics, Chemistry and Biology, Linkoeping Univ., Linkoeping (Sweden))

    2007-06-15

    The Swedish Energy Agency's project 'energy storage in gypsum', began in April 2007 and finished a year later. The objective was to demonstrate the potential of using gypsum to store and retrieve low-grade heat at a pilot scale (i.e. using 200 kg of gypsum). Gypsum undergoes a reversible reaction with water in which it stores or releases energy. Preliminary work indicated that when using commercially available gypsum powder, a packed bed would not allow sufficient mass or heat transfer. Preliminary work also revealed that simple fluidization was not possible with the very fine particles: stirred fluidization was the solution used. A pilot-scale unit was constructed (essentially a closed tank about 1 m in diameter and 1 m high). To store energy, hot, dry air is contacted with the gypsum to bring the temperature of the powder to about 110 deg C. Once the powder is 'dried' it is returned to room temperature and isolated from the surroundings - in this state energy is stored indefinitely. To recover the heat, water was atomized, mixed with warm air (to vaporize the water) and reacted with the gypsum. Typically we were able to recover about 6 kWh of energy, which is only about 20% of what is possible. This is partly the result of too little insulation on the reactor and a hesitation to over-hydrate the gypsum (which would result in solid plaster). We anticipate that this will at least double with increased operating experience. Overall gypsum behaves at a pilot scale as was expected; in terms of energy storage for space heating, it shows great promise. Our experiences to date have shown that using gypsum with a larger particle size (to allow simple fluidization) is an important improvement.

  4. Mechanism of gypsum hydration

    Directory of Open Access Journals (Sweden)

    Pacheco, G.

    1991-06-01

    Full Text Available There is an hypothesis that the mechanism o f gypsum hydration and dehydration is performed through two simultaneous phenomena. In this study we try to clear up this phenomenon using chlorides as accelerators or a mixture of ethanol-methanol as retarders to carry out the gypsum setting. Natural Mexican gypsum samples and a hemihydrate prepared in the laboratory are used. The following analytical techniques are used: MO, DRX, DTA, TG and DTG. In agreement with the obtained results, it can be concluded: that colloid formation depends on the action of accelerators or retarders and the crystals are a consequence of the quantity of hemihydrate formed.

    En el mecanismo de hidratación y deshidratación del yeso existe la hipótesis de que éste se efectúa por dos fenómenos simultáneos. Este estudio intenta esclarecer estos fenómenos, empleando: cloruros como aceleradores o mezcla etanol-metanol como retardadores para efectuar el fraguado del yeso. Se emplean muestras de yeso de origen natural mexicano y hemihydrate preparado en laboratorio; se utilizan técnicas analíticas: MO, DRX, DTA, TG y DTG. De acuerdo a los resultados obtenidos se puede deducir: que la formación del coloide depende de la acción de los agentes aceleradores o retardadores y que los cristales son consecuencia de la cantidad de hemihidrato formado.

  5. [Transdermal behavior of effective constituents in xuanbi gel plaster].

    Science.gov (United States)

    Liu, Yuehuan; Lu, Yang; Du, Shouying; Bai, Jie; Wang, Yue; Li, Huiyun

    2012-05-01

    To study the transdermal absorbability of gentiopicroside, naringin and protosappanin B contained in Xuanbi gel plaster. The Franz diffusing cells method was adopted for the in vitro model of rat belly skins. Three indexes, gentiopicroside, naringin and protosappanin B, residued in the accept liquid, skins and plaster were determined by HPLC. The penetration rates of gentiopicroside, naringin and protosappanin B were respectively 3.47, 1.59, 2.13 microg x cm(-2) x h(-1). After 24 h, their penetration rates were 25.42%, 11.73%, 17.78%, respectively. The residual quantities of gentiopieroside, naringin and protosappanin B in skin were 0.231, 0.593, 0.568 microg x cm(-2), ith the retention rates of 0.027%, 0.227%, 0.475%, respectively. The amount of residue of gentiopicroside, naringin and protosappanin B in plaster were 2179, 674, 278 microg, with the retention rates of 81.36%, 81.92%, 73.83%, respectively. The in vitro transdermal behavior of Xuanbi gel plaster is close to a zero-order process. The residual quantity the retention rate in skins is much lower than the penetration rate and the residual rate in plaster.

  6. Thermophysical properties of hydrophobised lime plasters - The influence of ageing

    Science.gov (United States)

    Pavlíková, Milena; Zemanová, Lucie; Pavlík, Zbyšek

    2017-07-01

    The building envelope is a principal responsible for buildings energy loses. Lime plasters as the most popular finishing materials of historical buildings and culture monuments influence the thermal behaviour as well as construction material of masonry. On this account, the effect of ageing on the thermophysical properties of a newly designed lime plasters containing hydrophobic admixture is analysed in the paper. For the comparative purposes, the reference lime plaster is tested. The ageing is accelerated with controlled carbonation process to simulate the final plasters properties. Basic characterization of the tested materials is done using bulk density, matrix density, and porosity measurements. Thermal conductivity and volumetric heat capacity are experimentally assessed using a transient impulse method. The obtained data revealed the significant changes of the both studied thermal parameters in the dependence on plasters composition and age. The assessed material parameters will be stored in a material database, where will find use as an input data for computational modelling of heat transport in this type of porous building materials and evaluation of energy-savings and sustainability issues.

  7. New Plaster Composite with Mineral Wool Fibres from CDW Recycling

    Directory of Open Access Journals (Sweden)

    Sonia Romaniega Piñeiro

    2015-01-01

    Full Text Available Over the last decade the intense activity of the building sector has generated large quantities of construction and demolition waste (CDW. In particular, in Europe around 890 million tons of CDW is generated every year; however, only 50% of them are recycled. In Spain, over the last years 40 millions of tons of construction and demolition waste have been generated. On the other hand, since the implementation of the Technical Building Code regulation the use of mineral wools as building insulation materials has become a widespread solution in both rehabilitation and new construction works, and because of that, this kind of insulation waste is increasing. This research analyzes the potential of a new composite (gypsum and fiber waste including several mineral wools waste into a plaster matrix. For this purpose, an experimental plan, characterizing the physical and mechanical behaviour as well as the Shore C hardness of the new composite, was elaborated fulfilling UNE Standards.

  8. Unravelling the mechanisms for plant survival on gypsum soils: an analysis of the chemical composition of gypsum plants from Turkey.

    Science.gov (United States)

    Bolukbasi, A; Kurt, L; Palacio, S

    2016-03-01

    Depending on their specificity to gypsum, plants can be classified as gypsophiles (gypsum exclusive) and gypsovags (non-exclusive). The former may further be segregated into wide and narrow gypsophiles, depending on the breadth of their distribution area. Narrow gypsum endemics have a putative similar chemical composition to plants non-exclusive to gypsum (i.e. gypsovags), which may indicate their similar ecological strategy as stress-tolerant plant refugees on gypsum. However, this hypothesis awaits testing in different regions of the world. We compared the chemical composition of four narrow gypsum endemics, one widely distributed gypsophile and six gypsovags from Turkey. Further, we explored the plasticity in chemical composition of Turkish gypsovags growing on high- and low-gypsum content soils. Differences were explored with multivariate analyses (RDA) and mixed models (REML). Narrow gypsum endemics segregated from gypsovags in their chemical composition according to RDAs (mainly due to higher K and ash content in the former). Nevertheless, differences were small and disappeared when different nutrients were analysed individually. All the gypsovags studied accumulated more S and ash when growing on high-gypsum than on low-gypsum soils. Similar to narrow gypsum endemics from other regions of the world, most local gypsum endemics from Turkey show a similar chemical composition to gypsovags. This may indicate a shared ecological strategy as stress-tolerant plants not specifically adapted to gypsum. Nevertheless, the narrow gypsum endemic Gypsophila parva showed a chemical composition typical of gypsum specialists, indicating that various strategies are feasible within narrowly distributed gypsophiles. © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

  9. Comparison of measurements between intraoral scanned digital model and plaster model%口内扫描数字化模型与硅橡胶制取石膏模型测量的对比研究

    Institute of Scientific and Technical Information of China (English)

    李晶; 王硕; 张达; 周彦恒

    2013-01-01

    Objective The purposc of this study was to evaluate the linear measurements difference between 3-dimensional digital models obtained with an intraoral scanner (Trios,3Shape,Denmark) and those on the corresponding plaster models.Methods Intraoral scan,and polyvinyl silicone impression were made and poured with type IV dental stone for each of 30 subjects.Three-dimensional images were obtained on this scanner and analyzed by using the Rapidform 2006 (Inustechnology,Korea)The scanning time was registrated by the scanner simultaneously.Toothwidth,arch width,arch length,curve of Spee measurements on the intraoral scanned model were compared with those on the corresponding plaster models measured with a digital caliper directly.Paired t tests were used to evaluate measurement differences between the two kinds of models.Independent t tests were used to evaluate differences of scanning time and crowding between upper and lower jaw.The interclass correlation(ICC) was calculated to evaluate the rcproducibility of the intraoral scanned models.Results No statistically significant differences were found between the measurements made directly on the dental casts and on intraoral scanned models.scan time within the upper jaw (411.9+162.2) s is greater than the lower jaw (290.8-+-94.9) s,(P<0.001).The interclass correlations were high.Conclusions No significant difference was found for the linear measurements between intraoral scanned digital model and plaster model,and the intraoral scanned model is expected to replace plaster model in the future.%目的 研究应用口内扫描仪采集数字化牙颌模型与硅橡胶石膏模型测量之间的差异性.方法 选择口腔正畸科门诊初诊患者共30例,分别制取上下颌硅橡胶印模并灌制成超硬石膏模型;并用口内扫描仪(Trios,3Shape,丹麦)获取数字化模型并记录上下颌口内扫描时间.对口内数字化模型和石膏模型的牙齿宽度,牙弓长度、宽度,Spee's曲度进行测量,应

  10. Evaluation of linear dimensional stability of various combinations of dental stone and plaster.

    Science.gov (United States)

    Adegbulugbe, I C; Oderinu, O H; Shaba, O P; Oremosu, O A

    2011-01-01

    It has been observed that due to the cheaper cost of dental plaster compared to dental stone, casts on which most of the dental prostheses and appliances were being fabricated in various laboratories were often mixtures of dental stone and dental plaster in order to reduce production cost. To evaluate the dimensional stability of various combinations of Dental Stone and Dental Plaster mixtures used to make dental casts. Alginate impressions of a master model of truncated metal cones were made and casts were produced by pouring with various combinations of dental stone and dental plaster mixtures. The linear dimensional differences between the inter-abutment distances on the casts were measured with an electronic caliper. One sample t-test and percentage differences were calculated. Dimensional variations for the distances measured using either 50% dental stone or 25% dental stone with plaster were statistically significant (p d" 0.05). Mixture of 75% dental stone and 25% dental plaster produced casts with no statistically significant dimensional variation from the master model (p e" 0.05). A mixture of 75% dental stone and 25% dental plaster could be used for procedures not requiring very accurate replica like mounting of teeth for dental training and for study models.

  11. Computer aided process of dimensional distortion determination of bounded plaster sandmix Part II

    OpenAIRE

    Pawlak, M.; Z. Niedźwiedzki

    2010-01-01

    A computer program allowing calculation of dimensional changes of mould made of cristobalite-gypsum composition in process of its heat treatment and preparation for molten metal casting is presented in this paper. The composition of the mixture and casting temperature to obtain cast of predetermined dimensions can be calculated using presented software. The base for program elaboration were the results of dilatometric test of bounded plaster sandmix composed of half hydrate α-CaSO4·0,5H2O of ...

  12. Computer aided process of dimensional distortion determination of bounded plaster sandmix Part II

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2010-01-01

    Full Text Available A computer program allowing calculation of dimensional changes of mould made of cristobalite-gypsum composition in process of its heat treatment and preparation for molten metal casting is presented in this paper. The composition of the mixture and casting temperature to obtain cast of predetermined dimensions can be calculated using presented software. The base for program elaboration were the results of dilatometric test of bounded plaster sandmix composed of half hydrate α-CaSO4·0,5H2O of various cristobalite ratio. Approximation was carried out in the range of temperatures 100÷700°C.

  13. Study on accuracy of plaster model after alginate impression taken through using different trays%不同局部托盘制取藻酸盐印模后的石膏模型精确性研究

    Institute of Scientific and Technical Information of China (English)

    郭建敏

    2014-01-01

    目的:系统评价不同局部托盘制取藻酸盐印模后的石膏模型精确性。方法利用局部托盘的方法,通过灌注硬石膏,在上颌部位制作藻酸盐标准模型的印模。而后依次测量龈缘近中边缘至远中边缘(4牙位)距离,以及远中边缘至近中边缘(2牙位)的距离,将上述两种距离与正常标准值进行统计学对比分析。参照局部托盘选择材料的不同,将研究对象分为铝制和钢制局部托盘两组;参照测量时间的不同,划分为1h和12h两组,上述各组依次测量6次。结果在近中边缘至27远中边缘距离测定时,全部的模型组与标准之间的差异均有统计学意义(P<0.05);在远中边缘至近中边缘的距离对比分析时,标准与钢制托盘之间差异无统计学意义(P>0.05),剩余各组模型与标准模型之间的比较差异有统计学意义(P<0.05);在时间对比方面,1h和12h两组模型进行统计分析,两个时间段之间的差异无统计学意义(P>0.05)。结论在藻酸盐印模制取的过程中,远中边缘至近中边缘的距离与标准的实体更相吻合;而近中边缘至27远中边缘钢制与铝制托盘印模的准确性基本一致;在临床中,制作近中边缘至27远中边缘距离,以及远中边缘至近中边缘两种印模,材料以及石膏模型的规格比例之间的差异无统计学意义。%Objective To systematically review accuracy of gypsum model after Alginate Impression taken through using different trays.Methods Through perfusion of anhydrite, impression of alginate standard model was made by the method of local tray in the upper. Distance from proximal middle edge to distal middle edge of gingival margin (4 teeth), and distance from distal middle edge to proximal middle edge (2 teeth) were measured respectively. The two distances were compared and analyzed statistically with normal standard values. Research subjects

  14. Thermophysical properties of hydrophobised lime plaster - Experimental analysis of moisture effect

    Science.gov (United States)

    Pavlíková, Milena; Pernicová, Radka; Pavlík, Zbyšek

    2016-07-01

    Lime plasters are the most popular finishing materials in renewal of historical buildings and culture monuments. Because of their limited durability, new materials and design solutions are investigated in order to improve plasters performance in harmful environmental conditions. For the practical use, the plasters mechanical resistivity and the compatibility with substrate are the most decisive material parameters. However, also plasters hygric and thermal parameters affecting the overall hygrothermal function of the renovated structures are of the particular importance. On this account, the effect of moisture content on the thermophysical properties of a newly designed lime plasters containing hydrophobic admixture is analysed in the paper. For the comparative purposes, the reference lime and cement-lime plasters are tested as well. Basic characterization of the tested materials is done using bulk density, matrix density, and porosity measurements. Thermal conductivity and volumetric heat capacity in the broad range of moisture content are experimentally accessed using a transient impulse method. The obtained data reveals the significant increase of the both studied thermal parameters with increasing moisture content and gives information on plasters behaviour in a highly humid environment and/or in the case of their possible direct contact with liquid water. The accessed material parameters will be stored in a material database, where can find use as an input data for computational modelling of coupled heat and moisture transport in this type of porous building materials.

  15. Plaster: our orthopaedic heritage: AAOS exhibit selection.

    Science.gov (United States)

    DeMaio, Marlene; McHale, Kathleen; Lenhart, Martha; Garland, Joshua; McIlvaine, Christopher; Rhode, Michael

    2012-10-17

    Plaster has been used for centuries as a stiffening agent to treat fractures and other musculoskeletal conditions that require rest, immobilization, or correction of a deformity. Despite modern metallurgy and internal stabilization, plaster casts and splints remain an important means of external stabilization. Casting is a dying art as modern internal and external fixation replace external immobilization. Proper casting technique is paramount. This manuscript outlines the history and chemistry of immobilization materials and techniques as well as the differences among them and the advantages and disadvantages of each. Historical references, peer-reviewed journals, textbooks, and primary sources were reviewed to provide data for this review. The history of immobilization reveals a progressive development and refinement of materials that culminated in Mathijsen's plaster bandage in 1851. In 1798, calcium sulfate (plaster of Paris) was introduced. By 1927, crinoline rolls dipped in plaster treated with binding agents facilitated application. Synthetic casting "tapes" (45% polyurethane resin and 55% fiberglass) were introduced in the 1970s. Splinting techniques are ancient, with development spurred by treatment of war wounds. Plaster relies on soft-tissue contact to maintain rigidity. There are well-known advantages, disadvantages, and complications of plaster management. Casting materials all create an exothermic reaction. Burns are associated with water temperatures of >24°C, more than eight layers (ply), and inadequate ventilation. The maximum water temperature must be lower with fiberglass casts. Plaster was the definitive management for most fractures for over 100 years until it was replaced by modern surgical techniques involving internal fixation in the latter part of the twentieth century. Plaster casts and splints remain an important treatment method for acute and chronic orthopaedic conditions.

  16. 石膏旋流器分离粒度模型建立研究%Study on cut size model establishment in gypsum cyclone

    Institute of Scientific and Technical Information of China (English)

    黄军; 安连锁

    2011-01-01

    针对火力发电厂WFGD系统中的石膏旋流器,基于旋流器的分离面是零速包络面与溢流管内径所形成的圆柱面的交界面的思想,对各关联公式进行了有效的推演,获取了分离粒度模型,并通过经验优化,建立了综合反映旋流器结构参数、物性参数和操作参数的分离性能的定量描述模型.该模型计算结果与试验结果的相对误差和其他传统经验模型的相对误差相比小0.5%-27.6%.%Aiming at the gypsum cyclone in the WFGD system of thermal power plant, the main idea is that the real separation surface is the interface between the locus of zero vertical velocity (LZVV) and the cylindrical surface forming by the inner diameter of vortex finder. Based on the separation theory, and then we can establish the cut size model by the effective deduction thinking on the relationship formula and practical optimization. The final cut size model which are consist of structure parameters, physical parameters and operating parameters can be set up, this model can describe the separation performance quantificationally. Compare with the test results, the relative error is 0.5%~27. 6% less than the other traditional empirical formula.

  17. [Application of modified plaster material and device in acupoint plaster therapy].

    Science.gov (United States)

    Liu, Jing-Xing; Wang, Kui; Wang, De-Li; Yang, Zong-Yun

    2013-02-01

    Through the analysis on the methods of medicinal paste preparation, the irritation of skin to medicine and the plaster materials adopted in acupoint plaster therapy for the prevention of winter-attacked disease in summer, the acupoint plaster materials and devices were improved. According to the differences in age, illness condition, acupoint and medicinal irritation of patients, the high-dosage, moderate-dosage and low-dosage series of medicine were prepared in proportion; 2. 5 mL and 5 mL syringes were manually reconstructed as the pushers for the delivery of the medicine paste of different specifications. The new-type materials such as spun-bonded non-woven fabrics, transparent dressing film and spun-laced non-woven skin-color stick plaster were adopted. In the operation, the medicine was classified and prepared more specifically. The dedicated acupoint plaster was characterized as less in skin irritation, breathable in property, convenient in practice and proper in stickiness. The plastic anti-seepage film in the middle and the medicine storage pool for stabilizing medicinal paste could avoid drug leakage. The medicinal paste pusher could achieve the even size, proper thickness and precise dosage of the paste. The new-type plaster material and the self-prepared innovated plaster device contribute to the development of acupoint plaster therapy in clinical application.

  18. The effects of K2SO4 solution on the compressive strength of dental gypsum type III

    Science.gov (United States)

    Adeilina, T.; Triaminingsih, S.; Indrani, D. J.

    2017-08-01

    Dental gypsum type III is used as a material for manufacturing working models of dentures. The aim of this study was to identify the effects of the addition of a K2SO4 solution on the compressive strength of gypsum type III. A compressive strength test was performed using a universal testing machine with a crosshead speed of 1 mm/min. The data were analyzed using a one-way ANOVA. The results showed that the compressive strength of gypsum type III with a 1.5% K2SO4 solution added was higher than for gypsum type III alone but lower than the compressive strength of gypsum type IV.

  19. Undercoat Roughness Impact on Venetian Plasters Adhesive Strength

    Directory of Open Access Journals (Sweden)

    Vladimir V. Vakor

    2011-11-01

    Full Text Available The article studies impact of undercoat fractions size on Venetian plasters adhesive strength, describes acrylic and lime plasters adhesive features, offers method for adherence junctions strength evaluation.

  20. Salt damage of stone, plaster and painted layers at a medieval church, South-Hungary

    Science.gov (United States)

    Török, Ákos; Galambos, Éva

    2016-04-01

    The Chapel of Pécsvárad is one of the best preserved and oldest medieval stone monument in South Hungary. It dates back to the 11th century. The interior of the chapel is decorated with wall paintings, which are later and probably originating from the late 12th century. The wall painting is partly preserved and it is located on an interior stone wall of the chapel facing to the East. The wall painting shows various forms of damage from salt efflorescence to chipping. The current research provides information on the in situ and laboratory analyses of salts, plasters, pigments and stone material suggesting mechanisms of decay that lead to partial loss of the painting. Both on site techniques and laboratory analyses were performed. Imaging techniques such as UV luminescence and IR thermography were used to identify the moist and salt covered zones on the wall surface. Portable moisture meter were also applied to map the wet zones in the interior and also at the external part of the chapel. Schmidt hammer and Duroscop were used for testing the surface strength of stone. Laboratory tests were focused on mineralogical and chemical compositional analyses. Small samples of stone, mortar, plaster and pigments were tested by optical microscopy, SEM-EDX, XRD and Thermogravimetric analyses. According to our tests the chapel was predominantly made of porous limestone and sandstone. Laboratory analyses proved that the major salt responsible for the damage of external walls are gypsum and halite, while in the interior part higher amount of halite and significant amount of sodium-nitrate were found besides gypsum. The painted layers are on Byzantine-type of plaster with organic compounds (plant fragments) and with a substrate layer rich in calcium carbonate. The identified pigments are dominantly earth pigments such as iron-oxide containing red and yellow (ochre) and green earth. A unique preservation of ultramarine blue in Hungary was found on the wall painting. The partial

  1. Atomic Oxygen Cleaning of Unpainted Plaster Sculptures

    Science.gov (United States)

    Banks, Bruce A.; Miller, Sharon K.

    2017-01-01

    Atomic oxygen erosion of polymers has been found to be a threat to spacecraft in low Earth orbit. As a result ground facilities have been developed to identify coatings to protect polymers such as used for solar array blankets. As a result of extensive laboratory testing, it was discovered that soot and other organic contamination on paintings could be readily removed by atomic oxygen interactions with minimal damage to the artwork. No method, other than dusting, has been found to be effective in the cleaning of unpainted plaster sculptures This presentation discusses the atomic oxygen interaction processes and how effective they are for cleaning soot damaged unpainted plaster sculptures.

  2. Water-resistant gypsum binder

    Directory of Open Access Journals (Sweden)

    Panchenko Alexander I.

    2016-01-01

    Full Text Available The authors developed a multi-component gypsum binder (MGB with an improved (by 1.8 to 2.2 times water resistance value in comparison with the initial gypsum and a softening factor value within the range of 0.85 to 0.91 through the introduction of a complex additive containing carbide mud and bio-silica. The use of a complex additive provides for the formation of a denser structure due to the formation of low-base calcium hydrated silicates at early stages of the hardening process under wet or dry air conditions. The developed binding agent has a lower (by 2.5 to 3 times open porosity, a greater compressive strength (by 1.4 to 1.6 times for a dry state and by 2.6 times in a water-saturated state and does not require any special curing conditions in contrast to the other multi-component gypsum binders. The authors show the influence of mud-and-silica additive on the properties of hardened MGB and suggest a method of computation of the optimum MGB composition for given components.

  3. Gypsum scaling in pressure retarded osmosis: experiments, mechanisms and implications.

    Science.gov (United States)

    Zhang, Minmin; Hou, Dianxun; She, Qianhong; Tang, Chuyang Y

    2014-01-01

    Pressure retarded osmosis (PRO) is an osmotically-driven membrane process that can be used to harvest salinity-gradient power. The PRO performance (both water flux and power density) can be severely limited by membrane fouling. The current study, for the first time, investigates PRO scaling in a bench-scale pressurized system using calcium sulfate dihydrate (gypsum) as a model scalant. In addition to the bulk feed solution (FS) saturation index (SI bulk), gypsum scaling was found to be strongly affected by the draw solution (DS) type and concentration, the applied hydraulic pressure, and the membrane orientation. The commonly recommended active layer facing draw solution (AL-DS) orientation was highly prone to internal scaling. In this orientation, severe internal concentration polarization (ICP) of scaling precursors induced gypsum clogging in membrane support layer even when the FS was undersaturated (e.g., SI bulk = 0.8). At higher SI bulk values, external gypsum crystal deposition occurred in addition to internal scaling. More severe scaling was observed when the DS contained scaling precursors such as Ca(2+) or SO4(2-), suggesting that the reverse diffusion of these precursors into the FS can significantly enhanced gypsum scaling. Increasing applied hydraulic pressure could enhance reverse solute diffusion and thus result in more severe gypsum scaling when the DS contained scaling precursors. A conceptual model, capturing the two important PRO scaling mechanisms (ICP of scaling precursors from FS and reverse diffusion of scaling precursors from the DS), is presented to rationalize the experimental results. Our results provide significant implications for PRO scaling control.

  4. Ancient gypsum mortars from Cyprus: characterization and reinvention

    Science.gov (United States)

    Theodoridou, M.; Ioannou, I.

    2012-04-01

    Mortars with various binding materials have been used across different pre-historic and historic periods to meet several construction applications, such as jointing masonry blocks, finishing walls and isolating water bearing structures. In the framework of an ongoing research programme (NEA ΥΠOΔOMH/NEKΥΠ/0308/17) funded by the Cyprus Research Promotion Foundation, the Republic of Cyprus and the European Union Regional Development Fund, 25 samples of gypsum mortars from different archaeological sites in Cyprus were collected and characterized following a systematic analytical approach. Petrographic observations of thin sections were carried out using polarizing optical microscope. Scanning electron microscopy equipped with energy dispersive X-ray microanalyser (SEM-EDX) was used to examine the microstructure and texture of the mortar samples and to determine semi-quantitatively the chemical composition and interface of their binders. X-ray diffraction (XRD) was performed to identify the main mineral crystalline phases of the specimens' binder and aggregates. Thermal analyses (TG/DTA) were used as a further confirmation of the material composition. The pore structure and volume of the ancient mortars were also determined by mercury intrusion porosimetry (MIP) analysis. Last but not least, a portable drilling resistance measurement system (DRMS) was used for micro-destructive assessment of the mechanical state of the samples. The results confirmed the predominant presence of hydrous calcium sulphate in all samples. Calcite was also found both in the binder and aggregates. Small proportions of SiO2 were also detected. The common ratio of binder to aggregates was 1:2.5. MIP showed porosity values between 14-48% and real densities between 1-1.7 g/cm3. The average pore diameters were smaller in the case of mortars with lower porosity. The use of DRMS indicated lower resistance to drilling for the case of joint mortars (as opposed to analysed gypsum plasters). This

  5. Asbestos in Plaster and Wall Systems

    Science.gov (United States)

    This collection of letters and clarification on final rules provides guidance on Asbestos National Emissions Standard for Hazardous Air Pollutants for asbestos-containing join compounds, and asbestos-containing materials found in plaster and wall systems.

  6. Plaster People...A La George Segal.

    Science.gov (United States)

    Boulay, Michele

    2003-01-01

    Describes an art project used with eleventh- and twelfth-grade students in which they created plaster self-portraits inspired by the work of George Segal. Includes directions for the casting and lists the art materials needed for the lesson. Explains that the project requires half a semester to complete. (CMK)

  7. Palatal Surface Area of Maxillary Plaster Casts

    DEFF Research Database (Denmark)

    Darvann, Tron Andre; Hermann, Nuno V.; Ersbøll, Bjarne Kjær

    2007-01-01

    Objective: To investigate the relationship between corresponding two-dimensional and three-dimensional measurements on maxillary plaster casts taken from photographs and three-dimensional surface scans, respectively. Materials and Methods: Corresponding two-dimensional and three-dimensional measu......Objective: To investigate the relationship between corresponding two-dimensional and three-dimensional measurements on maxillary plaster casts taken from photographs and three-dimensional surface scans, respectively. Materials and Methods: Corresponding two-dimensional and three......-dimensional measurements of selected linear distances, curve lengths, and (surface) areas were carried out on maxillary plaster casts from individuals with unilateral or bilateral cleft lip and palate. The relationship between two-dimensional and three-dimensional measurements was investigated using linear regression....... Results and Conclusions: Error sources in the measurement of three-dimensional palatal segment surface area from a two-dimensional photograph were identified as photographic distortion (2.7%), interobserver error (3.3%), variability in the orientation of the plaster cast (3.2%), and natural shape...

  8. Inexpensive, removable coating for plaster tooling

    Science.gov (United States)

    Dimino, J. M.; Martin, R. R.

    1970-01-01

    Procedure for thinning and spaying a vinyl material provides strippable film for plaster surfaces. Coating is low-cost, effective seal against moisture and other sources of damage. Coating consists of a mixture of hot-spray vinyl material and 30 to 50 percent by volume of methyl ethyl ketone.

  9. Comparison of space analysis performed on plaster vs. digital dental casts applying Tanaka and Johnston's equation.

    Science.gov (United States)

    Sanches, Júlia Olien; dos Santos-Pinto, Lourdes Aparecida Martins; dos Santos-Pinto, Ary; Grehs, Betina; Jeremias, Fabiano

    2013-01-01

    The purpose of this study was to compare dental size measurements, their reproducibility and the application of Tanaka and Johnston regression equation in predicting the size of canines and premolars on plaster and digital dental casts. Thirty plaster casts were scanned and digitized. Mesiodistal measurements of the teeth were then performed with a digital caliper on the plaster and digital casts using O3d software system (Widialabs©).The sum of the sizes of the lower incisors was used to obtain predictive values of the sizes of the premolars and canines using the regression equation, and these values were compared with the actual sizes of the teeth. The data were statistically analyzed by applying to the results Pearson's correlation test, Dahlberg's formula, paired t-test and analysis of variance (p plaster and digital casts. Despite an adequate reproducibility of the measurements performed on both casts, most measurements on the digital casts were higher than those on the plaster casts. The predicted space was overestimated in both models and significantly higher in the digital casts.

  10. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    Directory of Open Access Journals (Sweden)

    Taher Abu-Lebdeh

    2014-01-01

    Full Text Available The disposal of scrap tires is a challenging task and hence an innovative solution to meet these challenges is needed. Extensive work has been done on the utilization of waste tires in a variety of applications in asphalt pavements and concrete. However, previous investigations focus only on the mechanical properties of the rubberized materials, but few on the thermal performance. This is especially true for rubberized gypsum. Limited or no experimental data on the thermal performance of rubberized gypsum board are available. In this study, an experimental program is established to investigate the effect of amount and size of crumb rubber on the thermal properties of gypsum materials. Gypsum is replaced by four different percentage of crumb rubber: 10, 20, 30 and 40% by weight of gypsum and two sizes of crumb rubber (#30, #10_20 to make eight rubberized gypsum specimens. The prepared specimens were tested for thermal conductivity using an apparatus specially designed and constructed for this purpose. The experimental program was concluded by proposing an empirical equation to predict the thermal conductivity of rubberized gypsum board. Results indicated better thermal performance of the gypsum board due to the addition of crumb rubber. Thermal conductivity of the rubberized gypsum was 18-38% lower than the ordinary gypsum. It is concluded that thermal conductivity of rubberized gypsum decreases with the increase of crumb rubber regardless the size of the rubber and that thermal conductivity of mixtures contained 40% of rubber was about 38% lower than conventional mixture when crumb rubber #10_20 was added, while the thermal conductivity reduced by 22% when crumb rubber #30 was added. The study suggested for future work to investigate the effect of air voids size and ratio on the thermal conductivity of rubberized gypsum.

  11. Utility of a custom screw insertion guide and a full-scale, color-coded 3D plaster model for guiding safe surgical exposure and screw insertion during spine revision surgery.

    Science.gov (United States)

    Otsuki, Bungo; Takemoto, Mitsuru; Fujibayashi, Shunsuke; Kimura, Hiroaki; Masamoto, Kazutaka; Matsuda, Shuichi

    2016-07-01

    Several articles have described the use of screw insertion guides during primary spine surgery; however, the use of such a guide during revision surgeries has not been described. The purpose of this study is to describe the utility of a custom screw insertion (CSI) guide assembled using a novel method and a full-scale, color-coded 3D plaster (FCTP) model for safe and accurate revision surgery. The authors applied the CSI guide and the FCTP model in 3 cases. In the first case, a patient with multiple failed cervical spine surgeries underwent occipitocervicothoracic fusion. After a successful result for this patient, the authors applied the CSI guide in 2 other patients who underwent revision lumbar fusion surgeries to confirm the accuracy and the efficacy of the CSI guides in such cases. The models and guides were fabricated using rapid prototyping technology. The effectiveness of these methods was examined. The FCTP model was designed using CT data. During model assembly, implants inserted during previous surgery were removed virtually, and for the cervical spine, vertebral arteries were colored red for planning. The CSI guide was designed with 5 or 6 arms to fit the bone surface precisely after removing artifacts. Surgery was performed by referring to the FCTP model. Because the actual structure of the bone surface was almost identical to that of the FCTP model, surgical exposure around the complex bone shape proceeded smoothly. The CSI guides were positioned accurately to aid the successful insertion of a pedicle screw into the C-2 vertebra in the case of cervical revision surgery, and 4 pedicle screws for lumbar vertebrae in the 2 other patients. Postoperative CT scans showed that all screw positions closely matched those predicted during the preoperative planning. In conclusion, the FCTP models and the novel CSI guides were effective for safe and accurate revision surgery of the spine.

  12. The influence of inner hydrophobisation on water transport properties of modified lime plasters

    Science.gov (United States)

    Pavlíková, Milena; Pavlík, Zbyšek; Pernicová, Radka; Černý, Robert

    2016-06-01

    The effect of hydrophobic agent admixture on water vapour and liquid water transport properties of newly designed lime plasters is analysed in the paper. The major part of physico - chemical building deterioration is related to the penetration of moisture and soluble salts into the building structure. For that reason, the modified lime plasters were in the broad range of basic material properties tested. From the quantitative point of view, the measured results clearly demonstrate the big differences in the behaviour of studied materials depending on applied modifying admixtures. From the practical point of view, plaster made of lime hydrate, metakaolin, zinc stearate and air-entraining agent can be recommended for renovation purposes. The accessed material parameters will be used as input data for computational modelling of moisture transport in this type of porous building materials and will be stored in material database.

  13. Study of plaster finishes on San Pedro de los Francos church at Calatayud

    Directory of Open Access Journals (Sweden)

    Sánchez de Rojas, Mª I

    2007-06-01

    Full Text Available This study of the plaster finishes on San Pedro de los Francos Church at Calatayud revealed, firstly, the stratigraphic sequence based on the interpretation of the bonding interfaces; and secondly, the evolution of placement techniques from mudéjar style textured and painted false stonework (15th century to the smooth plastering and paint typical of later phases. Finally, scanning electron microscope (SEM, energy dispersive X-ray microanalysis (EDX and X-ray diffraction (XRD studies showed that gypsum and anhydrite are the main components of both binder and aggregate in these mortars. In other words, they constitute traditional multiphase plasters whose coarser particles or aggregate were a byproduct of the artisanal manufacturing process.El estudio de los enlucidos de la iglesia de San Pedro de los Francos de Calatayud ha permitido demostrar, en primer lugar, la secuencia estratigráfica mediante la lectura de la interfase de adherencia; en segundo lugar, la evolución de las técnicas de aplicación, desde el enlucido mudéjar, un fingido de piedra agramilado y pintado (siglo XV, hasta los enlucidos lisos y pinturas aplicados posteriormente. Y, finalmente, a través de los estudios de microscopía electrónica de barrido (SEM, microanálisis por energía dispersiva de rayos X (EDX y de difracción de rayos X (DRX, se ha determinado que son morteros en los que tanto el conglomerante como el árido son yeso y anhidrita, que correspondería a un yeso tradicional multifase, cuyos granos más gruesos analizados como áridos proceden del producto obtenido artesanalmente.

  14. [Experimental study on effects of acupoint application with Leima type II plaster on collagen-induced arthritis in rats].

    Science.gov (United States)

    Li, Peng; Fang, Jian-Qiao; Zhou, Ya-Feng

    2011-09-01

    To observe the therapeutic effect of acupoint application with Leima type II plaster on collagen-induced arthritis (CIA) in rats and probe its mechanism. Bovine type II collagen was injected intradermally into the middle line of the back to induce CIA model with 48 Wistar rats. Then the rats were randomly divided into a model control group (group A), a matrix control group (group B), acupoint application group with plaster of low concentration (group C) and high concentration plaster group (group D), 12 rats in each group. Group C and group D were treated with low and high concentration of Leima type II plaster, and "Shenzhu" (GV 12), "Zhiyang" (GV 9) and "Mingmen" (GV 4) were selected, each application for about 15 hours, once each day for 30 days. Group B was used the same method of acupoint application except using non-drug matrix plaster, and group A was not given any treatment. The morphous and the histopathological changes of affection joint were observed. The paw edema volume after 30 days treatment in group C was significantly lower than that in group B (P plaster has a good therapeutic effect on CIA rats and the protective mechanism is related to the reduction of anti-type II collagen antibody level so as to carry out anti-inflammatory effect and immunosuppression.

  15. Cements containing by-product gypsum

    Energy Technology Data Exchange (ETDEWEB)

    Bensted, J. [University of Greenwich, London (United Kingdom). School of Biological and Chemical Sciences

    1995-12-31

    Chemical by-product gypsum can readily replace natural gypsum in Portland cements and in blended cements like Portland pfa cement and Portland blast furnace cement without technical detriment in many instances. Indeed, sometimes the technical performance of the cement can be enhanced. The hydration chemistry is often changed, in that where there is at least some retardation of setting, more AFT phase (ettringite) is formed during early hydration at the expense of calcium silicate hydrates. By-product gypsum can also replace natural gypsum in speciality products like calcium aluminate cement-Portland cement mixes for producing quick setting cements and in calcium sulphoaluminate-type expansive cements. However, by-products gypsum have proved to be less successful for utilization in API Classes of oilwell cements, because of the greater difficulty in obtaining batch-to-batch consistency in properties like thickening time and slurry rheology. 11 refs., 3 figs., 5 tabs.

  16. Plaster body wrap: effects on abdominal fat.

    Science.gov (United States)

    Santos Moreira, Juliana; Melo, Ana Sofia Carneiro Pinto de; Noites, Andreia; Couto, Miriam Faria; Melo, Cristina Argel de; Adubeiro, Nuno Carvalho Freire de Almeida

    2013-12-01

    Abdominal fat is associated with metabolic disorders, leading to cardiovascular risk factors and numerous diseases. This study aimed to analyze the effect of plaster body wrap in combination with aerobic exercise on abdominal fat. Nineteen female volunteers were randomly divided into intervention group (IG; n = 10) performing aerobic exercise with plaster body wrap, and control group (CG; n = 9) performing only exercise. Subcutaneous and visceral fat were measured using ultrasound; subcutaneous fat was also estimated on analysis of skinfolds and abdominal perimeters. At the end of the 10-sessions protocol, the IG demonstrated a significant decrease (p ≤ 0.05) in subcutaneous fat at the left anterior superior iliac spine (ASIS) level and in iliac crest perimeter measurements. A large intervention effect size strength (0.80) was found in subcutaneous fat below the navel and a moderate effect size strength on the vertical abdominal skinfold (0.62) and the perimeter of the most prominent abdominal point (0.57). Comparing the initial and final data of each group, the IG showed a significant decrease in numerous variables including visceral and subcutaneous fat above and below the navel measured by ultrasound (p ≤ 0.05). Plaster body wrap in combination with aerobic exercise seems to be effective for abdominal fat reduction.

  17. Investigation of the type and content of gypsum on the dimensional stability and mechanical properties of gypsum particleboard

    Directory of Open Access Journals (Sweden)

    Hossein Rangavar

    2014-05-01

    Full Text Available In this study in order to investigate the effect of gypsum type on the physical and mechanical properties of gypsum Particleboard were used from two type Jebel and Micronize gypsum. To obtain the suitable amount of gypsum in manufacturing gypsum particleboard was used from the three levels 2.5:1, 2.75:1 and 3:1 of gypsum to dried mass of wooden materials. Physical and mechanical properties of manufactured board were carried out in accordance with European Norms (EN standard. The result showed that gypsum particleboard manufactured Jebel gypsum have the most mechanical properties (Bending strength, modulus of elasticity and internal bond strength, but physical properties (water absorption and thickness swelling of this boards was more than the boards manufactured from Micronize gypsum. Furthermore using 2.75 times gypsum to dried mass of wooden materials is also suitable in production gypsum particleboard.

  18. Measurement of soil moisture using gypsum blocks

    DEFF Research Database (Denmark)

    Friis Dela, B.

    the building. Consequently, measuring the moisture of the surrounding soil is of great importance for detecting the source of moisture in a building. Up till now, information has been needed to carry out individual calibrations for the different types of gypsum blocks available on the market and to account......For the past 50 years, gypsum blocks have been used to determine soil moisture content. This report describes a method for calibrating gypsum blocks for soil moisture measurements. Moisture conditions inside a building are strongly influenced by the moisture conditions in the soil surrounding...

  19. Measurement of soil moisture using gypsum blocks

    DEFF Research Database (Denmark)

    Friis Dela, B.

    For the past 50 years, gypsum blocks have been used to determine soil moisture content. This report describes a method for calibrating gypsum blocks for soil moisture measurements. Moisture conditions inside a building are strongly influenced by the moisture conditions in the soil surrounding...... the building. Consequently, measuring the moisture of the surrounding soil is of great importance for detecting the source of moisture in a building. Up till now, information has been needed to carry out individual calibrations for the different types of gypsum blocks available on the market and to account...

  20. Effects of gypsum on trace metals in soils and earthworms

    Science.gov (United States)

    Mined gypsum has been beneficially used for many years as an agricultural amendment. Currently a large amount of flue gas desulfurization (FGD) gypsum is produced by removal of SO2 from flue gas streams when fuels with high S content are burned. The FGD gypsum, similar to mined gypsum, can enhance c...

  1. Corrosion of bare and galvanized steel in gypsum

    Directory of Open Access Journals (Sweden)

    Gómez, Mercedes

    1988-12-01

    Full Text Available Gypsum is a relatively low-cost building material much abounding in our country. When it is put in contact with steel, it may produce high corrosion rates due to its pH value (close to 7. This work reports the results obtained in studying the corrosion rates of bare and galvanized steel in contact with gypsum and plaster, as well as the influence curing thermal treatment applied to gypsum, enviromental relative humidity and addition of compounds with different natures and purposes may have in such process. In-situ observations, as well as the measurement of the Polarization Resistance and the weight loss have been used as measurement technics. From the results obtained it has been possible to deduce that galvanized steel has better behaviour in dry enviroments than bare steel in the same conditions and moist atmosphere induces proportionally more corrosion in galvanized steel than in bare one. Additions to gypsum do not modified these conclusions, though it may be pointed out that addition of nitrites or lime improves the behaviour of bare steel, while galvanized behaviour is not modified. The addition of lime is not recommended because phenomena of dilated along time expansion may take place.

    El yeso es un material de construcción de relativo bajo coste y que, además, es muy abundante en nuestro país. Debido a su pH cercano a la neutralidad, cuando entra en contacto con el acero, este puede corroerse a elevadas velocidades. En esta comunicación se presentan los resultados de un estudio sobre la velocidad de corrosión del acero desnudo y galvanizado en contacto con yeso y escayola y la influencia que tienen: el tratamiento térmico del curado del yeso, la humedad relativa ambiental y la adición de aditivos de diversa naturaleza y finalidad. Como técnicas de medida se han utilizado la medida de la Resistencia de Polarización y de la pérdida de peso, así como observaciones visuales. De los resultados se puede deducir que en

  2. MOISTURE MOVEMENT (WICKING) WITHIN GYPSUM WALLBOARD

    Science.gov (United States)

    Gypsum wallboard with repeated or prolonged exposure to water or excess moisture can lose its structural integrity and provide a growth medium for biological contaminants. Poorly sealed buildings, leaking or failed plumbing systems, or improperly constructed HVAC systems can all ...

  3. Health economic evidence of 5% lidocaine medicated plaster in post-herpetic neuralgia.

    Science.gov (United States)

    Liedgens, Hiltrud; Obradovic, Marko; Nuijten, Mark

    2013-11-25

    Post-herpetic neuralgia (PHN) is the most common and most debilitating complication of herpes zoster, and involves considerable associated costs. This paper presents results from nine health economic studies undertaken in eight European countries that compared lidocaine medicated plaster with gabapentin and/or pregabalin in PHN. It aims to support the increasing need for published cost-effectiveness data for health care decision-making processes in Europe. All studies were based on a similar core Markov model with data derived from clinical trials, local Delphi panels, and official national price and tariff lists. The main outcome measure was cost per quality-adjusted life year gained; time without pain or intolerable adverse events was also included as a secondary outcome measure. All studies focused on an elderly population of patients with PHN who had insufficient pain relief with standard analgesics and could not tolerate or had contraindications to tricyclic antidepressants. Despite considerable differences in many of the variables used, the results showed remarkable similarity and suggested that use of lidocaine medicated plaster offered cost-savings in many of the countries studied, where it proved a highly cost-effective alternative to both gabapentin and pregabalin. Lidocaine medicated plaster is a cost-effective alternative to gabapentin and pregabalin in the treatment of PHN. These savings are largely the result of the superior safety profile of the lidocaine medicated plaster.

  4. [Exposure to hand-arm vibrations in orthopaedic plaster room: risk management].

    Science.gov (United States)

    Lembo, Marco; Lunghi, Alessandro; Leo, Erica; Ritrovato, Matteo; Cannatà, Vittorio; Capussotto, Carlo; Tirabasso, Angelo; Zaffina, Salvatore; Camisa, Vincenzo; Derrico, Pietro; Martella, Mauro; Marchetti, Enrico

    2016-03-24

    In hospitals, the use of vibrating tools, such as oscillating saws to cut plaster, can expose the staff to hand-arm vibrations. The aim of the study was to assess the exposure of workers to vibrations in the plaster room and then  identify the most appropriate  intervention for  prevention and protection to be implemented in order to minimize  exposure and  protect  workers' health, considering different individual hyper-susceptibility conditions. Four different models of plaster saws were examined for the evaluation.  Various measurements were made in normal working conditions of the operators. The values of acceleration and noise detected on the instruments  were  in line with those reported in the literature. The preventive measure adopted (replacing plaster saws currently used in the hospital with similar ones with lower vibration emission) was an adequate means of protection. Health surveillance activities  recorded a higher level of wellbeing, both environmentally and individually and, specifically, an increased protection level for the hyper-susceptibility conditions observed during health checks of exposed personnel  which will be monitored regularly by the Occupational Health Service.

  5. Estimating gypsum equirement under no-till based on machine learning technique

    Directory of Open Access Journals (Sweden)

    Alaine Margarete Guimarães

    Full Text Available Chemical stratification occurs under no-till systems, including pH, considering that higher levels are formed from the soil surface towards the deeper layers. The subsoil acidity is a limiting factor of the yield. Gypsum has been suggested when subsoil acidity limits the crops root growth, i.e., when the calcium (Ca level is low and/or the aluminum (Al level is toxic in the subsoil layers. However, there are doubts about the more efficient methods to estimate the gypsum requirement. This study was carried out to develop numerical models to estimate the gypsum requirement in soils under no-till system by the use of Machine Learning techniques. Computational analyses of the dataset were made applying the M5'Rules algorithm, based on regression models. The dataset comprised of soil chemical properties collected from experiments under no-till that received gypsum rates on the soil surface, throughout eight years after the application, in Southern Brazil. The results showed that the numerical models generated by rule induction M5'Rules algorithm were positively useful contributing for estimate the gypsum requirements under no-till. The models showed that Ca saturation in the effective cation exchange capacity (ECEC was a more important attribute than Al saturation to estimate gypsum requirement in no-till soils.

  6. Selection of plasters and renders for salt laden masonry substrates

    NARCIS (Netherlands)

    Groot, C.; Hees, R.P.J. van; Wijffels, T.J.

    2009-01-01

    The choice of a repair plaster or render by architects often appears to be the result of fortuitous circumstances, such as prior experience with a plaster or a recommendation by a producer. Seldom is the choice based on a sound assessment of the state of the building and the wall that is to be repai

  7. Sodium chloride crystallization in a "salt transporting" restoration plaster

    NARCIS (Netherlands)

    Lubelli, B.; Hees, R.P.J. van; Groot, C.J.W.P.

    2006-01-01

    In recent years several types of restoration plasters, especially developed for salt loaded substrates, have been introduced on the market. The behaviour of these plasters in the field is, however, not always satisfactory. The reasons for failures may be found both in the moisture and salt transport

  8. Investigation of field temperature in moulds of foamed plaster

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2007-12-01

    Full Text Available Plaster moulds used in precision foundry are characterized by a very low permeability which, in the case of classic plaster moulds, equals to about 0,01÷0,02 m2/(MPa·s. One of the most effective methods for increasing the permeability is a foaming treatment. Another characteristic feature of plaster is its very good insulating power which has influence on the process of solidification and cooling of a cast and also on a knock-out property. This insulating power is a function of thermophysical properties of plaster which, in turn, depend mainly on the mineralogical composition of the mould material, its bulk density as well as on the temperature of the pouring alloy. In the case of a foamed plaster mould an increase of the degree of foaming increases its porosity which causes a change in its thermophysical properties, thereby increasing susceptibility of the mass to overheating. The susceptibility of the plaster layer surrounding the cast to overheating is favorable because it makes it easier to knock-out of the cast by immersing the hot mould in cold water. Thermal and phase tensions that are created during this process cause fast destruction of plaster. This paper describes our investigations aimed at the determination of the dependence of the mould temperature field on the time of the cast stay in the mould, as recorded in a process of an unsteady heat flow. The determined data were planned to be used for estimation of the technological properties of the plaster mould. The tests were carried out using the plaster α-Supraduro and Alkanol XC (foaming agent. The test mould had a diameter of Ø 120 mm with centrally situated mould cavity of Ø 30 mm. Plaster moulds with a degree of foaming 20; 32,5 and 45% and comparatively from non-foaming plaster were tested and their temperatures were measured at the distance x=2; 9; 21; 25;27; 30 mm from the mould cavity within 25 min. Analysis of the results leads to the conclusion, that the highest

  9. POROSITY AND STRENGTH PROPERTIES OF GYPSUM BONDED INVESTMENT USING TERENGGANU LOCAL SILICA FOR COPPER ALLOYS CASTING

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    S. Z. M. NOR

    2015-07-01

    Full Text Available In this study, several formulations of gypsum bonded investment (GBI as a mould for copper alloy casting has been developed and their properties had been investigated. The mould was developed using Terengganu local silica sand with the average particle size of 220–250 µm, acted as a refractory and Plaster of Paris (POP as a binder. The formulations used were 75% local silica, 25% plaster and various amounts (31–37% of water. The compressive strength, tensile strength, porosity, core hardness and mould hardness properties of the prepared GBI were studied. It has been found that both compressive strength and tensile strength reduced with a water content due to an increment of mould porosity which was confirmed via Scanning Electron Microscopy analysis. The mould hardness was found unchanged, but the core hardness was slightly reduced with the increment of water. The compressive strength of GBI moulds developed in this work was in the range of 600–1100 kN/m2, which was sufficient for copper alloy casting.

  10. Development of Latent Heat Storage Phase Change Material Containing Plaster

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    Diana BAJARE

    2016-05-01

    Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.

  11. Development of Latent Heat Storage Phase Change Material Containing Plaster

    Directory of Open Access Journals (Sweden)

    Diana BAJARE

    2016-05-01

    Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.

  12. Health economic evidence of 5% lidocaine medicated plaster in post-herpetic neuralgia

    Directory of Open Access Journals (Sweden)

    Liedgens H

    2013-11-01

    Full Text Available Hiltrud Liedgens,1 Marko Obradovic,1 Mark Nuijten2 1Grunenthal GmbH, Aachen, Germany; 2Ars Accessus Medica, Amsterdam, the Netherlands Background: Post-herpetic neuralgia (PHN is the most common and most debilitating complication of herpes zoster, and involves considerable associated costs. Objective: This paper presents results from nine health economic studies undertaken in eight European countries that compared lidocaine medicated plaster with gabapentin and/or pregabalin in PHN. It aims to support the increasing need for published cost-effectiveness data for health care decision-making processes in Europe. Methods: All studies were based on a similar core Markov model with data derived from clinical trials, local Delphi panels, and official national price and tariff lists. The main outcome measure was cost per quality-adjusted life year gained; time without pain or intolerable adverse events was also included as a secondary outcome measure. All studies focused on an elderly population of patients with PHN who had insufficient pain relief with standard analgesics and could not tolerate or had contraindications to tricyclic antidepressants. Results: Despite considerable differences in many of the variables used, the results showed remarkable similarity and suggested that use of lidocaine medicated plaster offered cost-savings in many of the countries studied, where it proved a highly cost-effective alternative to both gabapentin and pregabalin. Conclusion: Lidocaine medicated plaster is a cost-effective alternative to gabapentin and pregabalin in the treatment of PHN. These savings are largely the result of the superior safety profile of the lidocaine medicated plaster. Keywords: post-herpetic neuralgia, zoster, cost-effectiveness, lidocaine, plaster

  13. Gypsum bonded investment for micro-structure casting of ZnAl4

    Institute of Scientific and Technical Information of China (English)

    Yang Chuang; Li Bangsheng; Ren Mingxing; Fu Hengzhi

    2010-01-01

    The effects of sintering temperature on the surface roughness of gypsum bonded investments were investigated to find the appropriate sintering temperature applied for micro-investment casting. The surface roughness tests were carried out at sintering temperatures ranging from room temperature to 1,000 ℃for investment compounds mixed from calcium sulphate α-hemihydrate and quartz powder (wt.%, 6:4; 5:5, 4:6, 3:7). In this experiment, each investment compound was prepared by pouring the investment materials into a plastic bottle with the good surface roughness (Ra ~0.2 urn). DTA-TG curves were measured using a thermal analyzer to investigate the difference of surface roughness at different temperatures. The results show that the surface roughness of gypsum bonded investment is temperature sensitive. The preheating temperature of the mold should be up to 600 ℃, but not over 700 ℃, and the investment compound with 60 % plaster and 40 % quartz powder is applicable for preparing the micro-structures. The micro-structures with 100 Mm diameter were produced in the present studies. The results show that the surface roughness of the casting is only Ra ~0.51 urn, slightly rougher than that of the investment mold.

  14. A Method for Optimizing Lightweight-Gypsum Design Based on Sequential Measurements of Physical Parameters

    Science.gov (United States)

    Vimmrová, Alena; Kočí, Václav; Krejsová, Jitka; Černý, Robert

    2016-06-01

    A method for lightweight-gypsum material design using waste stone dust as the foaming agent is described. The main objective is to reach several physical properties which are inversely related in a certain way. Therefore, a linear optimization method is applied to handle this task systematically. The optimization process is based on sequential measurement of physical properties. The results are subsequently point-awarded according to a complex point criterion and new composition is proposed. After 17 trials the final mixture is obtained, having the bulk density equal to (586 ± 19) kg/m3 and compressive strength (1.10 ± 0.07) MPa. According to a detailed comparative analysis with reference gypsum, the newly developed material can be used as excellent thermally insulating interior plaster with the thermal conductivity of (0.082 ± 0.005) W/(m·K). In addition, its practical application can bring substantial economic and environmental benefits as the material contains 25 % of waste stone dust.

  15. Evaluation of the Population Pharmacokinetic Properties of Lidocaine and its Metabolites After Long-Term Multiple Applications of a Lidocaine Plaster in Post-Herpetic Neuralgia Patients.

    Science.gov (United States)

    Bursi, Roberta; Piana, Chiara; Grevel, Joachim; Huntjens, Dymphy; Boesl, Irmgard

    2017-01-12

    Lidocaine 5% medicated plaster is the first lidocaine containing product for chronic use. As no previous investigations have been conducted to evaluate the population pharmacokinetics of long-term exposure to lidocaine 5% medicated plasters, further insights into the evaluation of the pharmacokinetic properties of lidocaine and its metabolites were needed for the assessment of its safety. The population pharmacokinetic properties of lidocaine and its metabolites were evaluated after multiple applications of lidocaine 5% medicated plasters based on data collected for up to 14.5 months from two phase III clinical trials (up to 2.5 months in the first trial, and up to 12 months in a follow-up trial) in post-herpetic neuralgia patients. Modeling was performed using nonlinear mixed effects as implemented in NONMEM(®) (nonlinear mixed-effect modeling) v.5. A stepwise forward inclusion and backward elimination procedure were used for covariate model building. The model provides reliable estimates of the pharmacokinetic behavior of lidocaine after medicated plaster application. It was validated using simulations and showed adequate predictive properties. Apparent Clearance was estimated to be 48 L/h after application of two or fewer plasters, whereas its value increased to 67 L/h after application of three plasters. Model-based simulations predicted no accumulation of lidocaine or any of its metabolites after long-term exposure of three simultaneous plasters up to 1 year. The variability explained by adding covariates into the model for the long-term exposures of lidocaine following one plaster or three simultaneous plaster applications was found to be very small with respect to the overall between-subject variability. In conclusion, exposure to lidocaine after the application of the lidocaine medicated plaster was found to be primarily affected by the number of plasters simultaneously applied, i.e., it increased with the number of applied patches, but less than

  16. Design of Cold-Formed Steel Screw Connections with Gypsum Sheathing at Ambient and Elevated Temperatures

    Directory of Open Access Journals (Sweden)

    Wei Chen

    2016-09-01

    Full Text Available Load-bearing cold-formed steel (CFS walls sheathed with double layers of gypsum plasterboard on both sides have demonstrated good fire resistance and attracted increasing interest for use in mid-rise CFS structures. As the main connection method, screw connections between CFS and gypsum sheathing play an important role in both the structural design and fire resistance of this wall system. However, studies on the mechanical behavior of screw connections with double-layer gypsum sheathing are still limited. In this study, 200 monotonic tests of screw connections with single- or double-layer gypsum sheathing at both ambient and elevated temperatures were conducted. The failure of screw connections with double-layer gypsum sheathing in shear was different from that of single-layer gypsum sheathing connections at ambient temperature, and it could be described as the breaking of the loaded sheathing edge combined with significant screw tilting and the loaded sheathing edge flexing fracture. However, the screw tilting and flexing fracture of the loaded sheathing edge gradually disappear at elevated temperatures. In addition, the influence of the loaded edge distance, double-layer sheathing and elevated temperatures is discussed in detail with clear conclusions. A unified design formula for the shear strength of screw connections with gypsum sheathing is proposed for ambient and elevated temperatures with adequate accuracy. A simplified load–displacement model with the post-peak branch is developed to evaluate the load–displacement response of screw connections with gypsum sheathing at ambient and elevated temperatures.

  17. Moisture and salt transport in three-layer plaster/substrate systems

    NARCIS (Netherlands)

    Petković, J.; Huinink, H.P.; Pel, L.; Kopinga, K.; Hees, R.P.J. van

    2010-01-01

    We have investigated whether a plaster which has two plaster layers with different pore sizes can act as a salt accumulating plaster system, in which salt crystallizes in the base layer of the plaster and not in the substrate or at the external surface. We used two substrates; fired-clay brick and B

  18. Gray level co-occurrence and random forest algorithm-based gender determination with maxillary tooth plaster images.

    Science.gov (United States)

    Akkoç, Betül; Arslan, Ahmet; Kök, Hatice

    2016-06-01

    Gender is one of the intrinsic properties of identity, with performance enhancement reducing the cluster when a search is performed. Teeth have durable and resistant structure, and as such are important sources of identification in disasters (accident, fire, etc.). In this study, gender determination is accomplished by maxillary tooth plaster models of 40 people (20 males and 20 females). The images of tooth plaster models are taken with a lighting mechanism set-up. A gray level co-occurrence matrix of the image with segmentation is formed and classified via a Random Forest (RF) algorithm by extracting pertinent features of the matrix. Automatic gender determination has a 90% success rate, with an applicable system to determine gender from maxillary tooth plaster images. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. GYPSUM DEPOSITS IN THE REPUBLIC OF CROATIA

    Directory of Open Access Journals (Sweden)

    Anto Gabrić

    2002-12-01

    Full Text Available The occurences and deposits of gypsum can be found in big karst poljes (Sinjsko, Vrličko, Petrovo, Kosovo and Kninsko as well as in tectonnically predestined river valleys of Zrmanja, Butišnica and Una. There also appear spatially localized occurences on the island of Vis and in the vicinity of Samobor. Evaporites (gypsum and anhydrite with adjoining overlying clastic rocks (red sandstones, siltites and pelites, carbonate rocks (dolomites and limestones and porous carbonate breccias (Rauhwackes were deposited during the period of Upper Permian. The recent position of the Upper Permian beds is a result of complex tectonic, particularly neotectonic, movements and diapiric displacements. Evaporites were deposited in marginal areas of the epicontinental marine basin, in a period of favourable conditions for the sabkha and playa sedimentation due to the continuous shoreline progradation. The Upper Permian age of these sediments in Dalmatio is proved by the characteristic mineral paragenesis and palinological determinations in elastics rocks, as well as by isotope analyses of sulphure in gypsum. Gypsum is a significant ore mineral resource in building, cement production, as well as in a number of tehnological processes used in chemical industry and elsewhere. According to the recent investigations gypsum is predestined to serve as an ore mineral resource of significant perspectives (the paper is published in Croatian.

  20. Effect of an admixture from Agave americana on the physical and mechanical properties of plaster

    Directory of Open Access Journals (Sweden)

    Ochoa, J. C.

    2013-03-01

    Full Text Available Physical and mechanical properties of a plaster paste added with an organic admixture, of the leaves of Agave americana, were studied. Plastic consistency behavior was evaluated and the water/gypsum(w/g ratio was determined for each dosage of the admixture. Admixtur eeffect on setting was evaluated too. The chemical transformation of the hemihydrated form to gypsum (dihydrated form was studied using a novel technique based on a moisture analyzer by halogen light. Flexural and compressive strengths were measured. The results show that ,for the same consistency, accordingly mechanical strengths were improved too. The setting times were increased which would enhance the application time of plaster and would reduce plastic shrinkage, common problems in this type of material. The changes in these physical properties not substantially affect the final mechanical strengths.

    Se estudiaron algunas propiedades físicas y mecánicas de pastas de yeso de construcción adicionadas con un aditivo de origen orgánico, producto de las hojas de la planta Agave americana. Se evaluó el comportamiento plástico de la pasta mediante ensayos de consistencia y se determinó, para cada dosificación, su relación agua/ yeso (a/y. Se evaluó la incidencia del aditivo en los tiempos de fraguado. La transformación química del hemihidrato a yeso dihidrato se estudió mediante una novedosa técnica basada en un analizador de humedad por luz halógena. Se midieron las resistencias mecánicas a flexo-tracción y a compresión. Los resultados del estudio muestran que, para una misma consistencia, se mejoran las resistencias mecánicas. Los tiempos de fraguado de la pasta se aumentaron lo que ayudaría mejorar los tiempos de aplicación del yeso y a disminuir las retracciones plásticas. Las modificaciones de estas propiedades físicas no afectan considerablemente las resistencias mecánicas finales.

  1. Problems with plastered external heat insulation. Probleme mit verputzter Aussenwaermedaemmung

    Energy Technology Data Exchange (ETDEWEB)

    Epple, H.; Foglia, A.; Preisig, H.; Pfefferkorn, J.

    1984-01-01

    Concerning execution, maintenance and service life, walls with plastered external heat insulation constitute an economic method. Owing to experience gained with plastered external heat insulation, it is possible today to provide reliable information on requirements made on ground material and operational execution. The author intends to contribute to a prevention of defects by giving concise examples. A survey on different types of external heat insulation is followed by a treatment of the problem areas of roof-edge connection, base end under ground, modernization of old buildings and cracks in plaster. Principal statements are made concerning steam diffusion, planning, materials and execution.

  2. Dilatometric examination of moulds with plaster binder

    Directory of Open Access Journals (Sweden)

    M. Nadolski

    2011-01-01

    Full Text Available Investigations concerning thermal expansion of moulding materials with plaster binder have been performed for two mixture compositionsof Authors’ own design, as well as for the material used in jewellery industry under the Prima-Cast trade name, and for ThermoMold 1200moulding material. The results of dilatometric examinations of these materials, carried out within the temperature range from about 20°Cto 650°C by means of the DA-3 automatic dilatometer, have been compared. An analysis of this comparison has revealed that it is thematrix composition which is decisive for the magnitude of dimensional changes of moulds, and that applying components which do notexhibit polymorphic transformations reduces dimensional changes of a mould during its thermal treatment.

  3. The Plastered Skulls from the Pre-Pottery Neolithic B Site of Yiftahel (Israel) – A Computed Tomography-Based Analysis

    Science.gov (United States)

    Slon, Viviane; Sarig, Rachel; Hershkovitz, Israel; Khalaily, Hamoudi; Milevski, Ianir

    2014-01-01

    Three plastered skulls, dating to the Pre-Pottery Neolithic B, were found at the site of Yiftahel, in the Lower Galilee (Israel). The skulls underwent refitting and restoration processes, details of which are described herein. All three belong to adults, of which two appear to be males and one appears to be a female. Virtual cross-sections were studied and a density analysis of the plaster was performed using computed tomography scans. These were utilized to yield information regarding the modeling process. Similarities and differences between the Yiftahel and other plastered skulls from the Levant are examined. The possible role of skull plastering within a society undergoing a shift from a hunting-gathering way of life to a food producing strategy is discussed. PMID:24586625

  4. Gypsum karst in Italy: a review

    Science.gov (United States)

    De Waele, Jo; Chiarini, Veronica; Columbu, Andrea; D'Angeli, Ilenia M.; Madonia, Giuliana; Parise, Mario; Piccini, Leonardo; Vattano, Marco; Vigna, Bartolomeo; Zini, Luca; Forti, Paolo

    2016-04-01

    Although outcropping only rarely in Italy, gypsum karst has been described in detail since the early XXth century (Marinelli, 1917). Gypsum caves are now known from almost all Italian regions (Madonia & Forti, 2003), but are mainly localised along the northern border of the Apennine chain (Emilia Romagna and Marche regions), Calabria, and Sicily, where the major outcrops occur. Recently, important caves have also been discovered in the underground gypsum quarries in Piedmont (Vigna et al., 2010). During the late 80s and 90s several multidisciplinary studies have been carried out in many gypsum areas. All this work converged into a comprehensive overview in 2003 (Madonia & Forti, 2003). Further detailed studies focused on the gypsum areas of Emilia Romagna (Chiesi et al., 2010; Forti & Lucci, 2010; Demaria et al., 2012; De Waele & Pasini, 2013; Ercolani et al., 2013; Columbu et al., 2015; Lucci & Piastra, 2015; Tedeschi et al., 2015) and of Sicily (Madonia & Vattano, 2011). Sinkholes related to Permo-Triassic gypsum have been studied in Friuli Venezia Giulia (Zini et al., 2015). This presentation will review the state of the art regarding different aspects of evaporite karst in Italy focusing on the main new results. References Chiesi M., et al. (2010) - Origin and evolution of a salty gypsum/anhydrite karst spring: the case of Poiano (Northern Apennines, Italy). Hydrogeology Journal, 18, pp. 1111-1124. Columbu A. et al. (2015) - Gypsum caves as indicators of climate-driven river incision and aggradation in a rapidly uplifting region. Geology, 43(6), 539-542. Demaria D. et al. (Eds.) (2012), Le Grotte Bolognesi, GSB-USB, 431 p. De Waele J., Pasini G. (2013) - Intra-messinian gypsum palaeokarst in the northern Apennines and its palaeogeographic implications. Terra Nova 25, pp. 199-205. Ercolani M., et al. (Eds.) (2013), I Gessi e la Cave i Monte Tondo. Studio multidisciplinare di un'area carsica nella Vena del Gesso Romagnola. Memorie Ist. It. Spel. II(26), 559 p

  5. Effect of high temperatures on gypsum paste and mortar

    Science.gov (United States)

    Krejsová, Jitka; Doleželová, Magdalena; Vimmrová, Alena

    2016-07-01

    This paper describes the influence of high temperatures on some physical and mechanical properties of gypsum mixtures. Two gypsum mixtures were designed, first one was composed of gypsum and citric acid and the second one contained standardized sand also. The samples were exposed to temperatures from 50°C to 1000°C. Results show, that strength changes caused by high temperatures are significant in both mixtures and that the thermal shrinkage is reduced by adding sand to a gypsum mixture.

  6. [Study of the stability of current plaster substitutes].

    Science.gov (United States)

    Wruhs, O

    1986-06-01

    In connection with company independent test series the clinically required usefulness of four different modern plaster substitutes were examined. A comparison of breakage resistance, deformation and relation of price versus stability of plaster bandages were considered. The advantage of using these materials, especially in case of prolonged cast immobilization, is-despite of higher financial costs - more appropriate because of lower weight, increased durability and hygienical comfort for the patients.

  7. Mechanical properties of gypsum board at elevated temperatures

    Science.gov (United States)

    S.M. Cramer; O.M. Friday; R.H. White; G. Sriprutkiat

    2003-01-01

    Gypsum board is a common fire barrier used in house and general building construction. Recently, evaluation of the collapses of the World Trade Center Towers highlighted the potential role and failure of gypsum board in containing the fires and resisting damage. The use of gypsum board as primary fire protection of light-flame wood or steel construction is ubiquitous....

  8. Dissolution of Gypsum from field observations

    Directory of Open Access Journals (Sweden)

    Klimchouk A.

    1996-01-01

    Full Text Available The paper reports the results of field measurements of gypsum dissolution in various countries (Ukraine, Spain, Italy and others and in different environments (river waters, precipitation, vadose zone, unconfined aquifer, perched cave lakes, ephemeral streams in caves, confined aquifer, cave air.

  9. Phosphor plasters of CaSO{sub 4}:Dy on the courtyard wall of Djehuty's tomb (Luxor, Egypt)

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Guinea, J. [Museo Nacional de Ciencias Naturales, CSIC. C/ Jose Gutierrez Abascal 2, 28006 Madrid (Spain)], E-mail: guinea@mncn.csic.es; Sanchez-Moral, S. [Museo Nacional de Ciencias Naturales, CSIC. C/ Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Correcher, V.; Sanchez-Munoz, S. [CIEMAT. Av. Complutense 22, 28040 Madrid (Spain); Cuezva, S. [Museo Nacional de Ciencias Naturales, CSIC. C/ Jose Gutierrez Abascal 2, 28006 Madrid (Spain); Cremades, A. [Dpt. Fisica de Materiales, Facultad de Fisicas, Universidad Complutense, 28040 Madrid (Spain); Benavente, D. [Dpto. CC. de la Tierra y del Medio Ambiente. Univ. Alicante, 03080 Alicante (Spain); Galan, J.M. [Instituto de Filologia, CSIC. C/Duque de Medinaceli 6, 28014 Madrid (Spain)

    2008-02-15

    The X-ray diffraction (XRD) and environmental scanning electron microscopy (ESEM) analyses of plasters collected from the courtyard walls of Djehuty's tomb show anhydrite, calcite, dolomite, quartz, alkali feldspars and accessorial amounts of halite and illite. The external outer bed is mainly composed by anhydrite, since the original hydrous phases of gypsum plaster were desiccated during thirty centuries in the dry land environment of the Luxor area, under low relative humidity and high temperatures. The luminescence analyses by thermoluminescence (TL) and cathodoluminescence (CL) demonstrate as one plaster sample (m8), i.e., 95% anhydrite, displays a gigantic TL emission of 33 555 a.u. and a SEM/CL emission of 2319 a.u. maxima peak. The spectra CL also exhibits a 484 nm peak attributable to the classic {sup 4}F{sub 9/2}{yields}{sup 6}H{sub 15/2} transition circa 490 nm of Dy{sup 3+} and a 573 nm emission of Dy{sup 3+} masked in a broad emission band centered at 620 nm. The common presence of sodium minerals such as halite or albite together with the probable presence of sodium in waters points to Na{sup +} ions acting as compensators of Dy{sup 3+} to maintain the electrical neutrality of the CaSO{sub 4}:Dy phosphor lattice. Further analyses of more plaster CaSO{sub 4} micro-samples could demonstrate if this observation is just an isolated mineralogical chance or an intentional archaeological handling.

  10. Physical and mechanical characterization of gypsum boards containing phase change materials for latent heat storage

    Directory of Open Access Journals (Sweden)

    Oliver-Ramírez, A.

    2011-09-01

    Full Text Available This article describes the design and manufacture of a gypsum board which, despite its 45 % wt content of phase change materials, meets the minimum physical and mechanical requirements laid down in the legislation on gypsum plasters (Spanish and European standard UNE EN 13279 and Spanish specifications for gypsum acceptance, RY 85. Under this design, a one-metre square, 1.5-cm thick board contains 4.75 kg of PCM, much more than in any prior drylining (the maximum attained to date is 3 kg per m2. The mechanical and physical characteristics of this new composite were previously improved with two joint-action additives: polypropylene fibres and melamine formaldehyde as a dispersing agent. In the 20-30 ºC temperature range, a gypsum board 1.5 cm thick containing this percentage of PCMs can store five times more thermal energy than conventional plasterboard of the same thickness, and the same amount of energy as half-foot hollow brick masonry.

    En esta investigación se ha diseñado y fabricado un panel de escayola que incorpora un 45% en peso de material de cambio de fase, manteniendo las propiedades físicas y mecánicas exigidas en la normativa de aplicación para yesos de construcción (UNE EN 13279 y referencias a la RY 85. Así, un panel de 1,0 m2 y 1,5 cm de espesor, contiene 4,75 kg de PCM, cantidad muy superior a la conseguida hasta la fecha (3 kg/m2. Para ello se ha mejorado previamente sus prestaciones mecánicas y físicas mediante adiciones binarias: fibras de polipropileno y dispersión de melanina formaldehído. Este porcentaje es capaz de almacenar en 1,5 cm de espesor cinco veces la energía térmica de un panel de cartón yeso con el mismo espesor y la misma cantidad que una fábrica de 1/2 pie de ladrillo hueco, en el rango de temperaturas próximas a la de confort (20-30 ºC.

  11. Prediction of drilling micro-hole in CO{sub 2} laser irradiated sticking plaster

    Energy Technology Data Exchange (ETDEWEB)

    Rao Zhiming; Lu Yanzhao [Wuhan National Laboratory for Optoelectronic, the College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei (China); Wu Tao [School of Science, Wuhan Institute of Technology, Wuhan 430073 (China); Du Jianqiang, E-mail: raozm24@163.com [Depart of Computer Science, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, Jiangxi (China)

    2011-02-01

    This paper reports a simulation model of drilling micro-hole in sticking plaster heated with a 1064 nm continuous CO{sub 2} laser beam. Laser spot sizes ranged from 0.1 to 0.2mm diameter with axial irradiance power levels of 25-100W. To apply software Ansys, the measured steady-state surface temperature is calculated to rise with both increasing beam power and incident laser irradiance. For temperatures above 450 deg. C, sticking plaster vaporized into ventilation hole, and the size of ventilation hole 0.15mm diameter spent 1.7ms heated with laser power lever of 100W with the size of spot 0.15mm diameter, in good accordance with reported in earlier experiments studies. Similarly, the size of ventilation holes changed with beam power and laser spot diameter. These results show that software Ansys can be used to predict drilling micro-hole in CO{sub 2} laser irradiated sticking plaster and the result of simulation can guide to laser drilling experiments.

  12. Mortality among unionized construction plasterers and cement masons.

    Science.gov (United States)

    Stern, F; Lehman, E; Ruder, A

    2001-04-01

    Plasterers perform a variety of duties including interior and exterior plastering of drywall, cement, stucco, and stone imitation; the preparation, installation, and repair of all interior and exterior insulation systems; and the fireproofing of steel beams and columns. Some of the current potential toxic exposures among plasterers include plaster of Paris, silica, fiberglass, talc, and 1,1,1-trichloroethylene; asbestos had been used by the plasterers in the past. Cement masons, on the other hand, are involved in concrete construction of buildings, bridges, curbs and gutters, sidewalks, highways, streets and roads, floors and pavements and the finishing of same, when necessary, by sandblasting or any other method. Exposures include cement dust, silica, asphalt, and various solvents. Proportionate mortality ratios (PMRs) and proportionate cancer mortality ratios (PCMRs) were calculated for 99 causes of death among 12,873 members of the Operative Plasterers' and Cement Masons' International Association who died between 1972 and 1996 using United States age-, race-, and calender-specific death rates. Statistical significance (P value) of results was based upon the Poisson distribution. Among plasterers, statistically significant elevated mortality was observed for asbestosis, where the PMR reached 1,657 (P < 0.01) with eleven observed deaths and less than one death expected, for lung cancer (PCMR = 124, P < 0.01), and for benign neoplasms (PMR = 210, P < 0.05). Among cement masons, statistically significant elevated mortality was observed for cancer of the stomach (PCMR = 133, P < 0.01), benign neoplasms (PMR = 132, P < 0.01), and poisonings (PMR = 159, P < 0.05). Except for poisonings, which were not thought to be occupationally related, all of the statistically significant results occurred among those members who entered the union prior to 1950. However, the risk for lung cancer among plasterers was still elevated among those entering the union after 1970 as was the

  13. THERMAL CONDUCTIVITY OF RUBBERIZED GYPSUM BOARD

    OpenAIRE

    Taher Abu-Lebdeh; Ellie Fini; Ashraf Fadiel

    2014-01-01

    The disposal of scrap tires is a challenging task and hence an innovative solution to meet these challenges is needed. Extensive work has been done on the utilization of waste tires in a variety of applications in asphalt pavements and concrete. However, previous investigations focus only on the mechanical properties of the rubberized materials, but few on the thermal performance. This is especially true for rubberized gypsum. Limited or no experimental data on the thermal performance of rubb...

  14. Tunisian gypsums: Characteristics and use in cement

    Science.gov (United States)

    Mahmoudi, Salah; Bennour, Ali; Chalwati, Youssef; Souidi, Khouloud; Thabet, Manel; Srasra, Ezzedine; Zargouni, Fouad

    2016-09-01

    Gypsum materials of hundred meters thickness and interbedded with marine claystones and limestones from different paleogeographic sectors in the Tunisian territory are studied to assess their suitability for cement production. For this reason, thirty representative samples are analysed by chemical, physical and geotechnical tests. The obtained results for the studied gypsum materials are compared to Tunisian and European norms and with the local cements, currently marketed and which obey international norms. Indeed, for all samples hydraulic modulus HM, silica modulus SM and alumina modulus AM vary from (2.37-2.44), (2.48-2.68) and (1.45-2.5), respectively; whereas the required values for these modulus are (1.5-2.5), (2-3) and (1.5-2.5). The same behavior is observed for mineralogical analyses of C3S, C2S, C3A and C4AF and compressive strength at different ages. Briefly, Tunisia contains important reserves of gypsum scattered and spread over the Tunisian territory and can be used for cement production.

  15. Speleothems in gypsum caves and their paleoclimatological significance

    Science.gov (United States)

    Calaforra, J. M.; Forti, P.; Fernandez-Cortes, A.

    2008-01-01

    This article highlights the relationship between speleothems growing inside gypsum caves and the particular climate that existed during their development. Speleothems in gypsum caves normally consist of calcium carbonate (calcite) or calcium sulphate (gypsum) and the abundance of such deposits greatly differs from zone to zone. Observations carried out over the last 20 years in gypsum caves subjected to very different climates (Italy, Spain, New Mexico, northern Russia, Cuba, Argentina) highlight wide variation in their cave deposits. In arid or semi-arid climates, the speleothems are mainly composed of gypsum, whilst in temperate, humid or tropical regions, carbonate formations are largely predominant. In polar zones no speleothems develop. These mineralogical details could be useful paleoclimatic indicators of climate change. The interpretation proposed is based on the fact that in gypsum karst the kind of speleothems deposited is determined by competition between the two principal mechanisms that cause precipitation of calcite and gypsum. These mechanisms are completely different: calcite speleothem evolution is mainly controlled by CO2 diffusion, while gypsum deposits develop mostly due to evaporation. Therefore, the prevalence of one kind of speleothem over the other, and the relationship between the solution precipitation processes of calcite and gypsum, may provide evidence of a specific paleoclimate. Additionally, other non-common deposits in gypsum caves like moonmilk, cave rafts and dolomite speleothems can be used as markers for the prevalence of long, dry periods in humid areas, seasonal changes in climate, or rainfall trends in some gypsum areas. Moreover, the dating of gypsum speleothems could contribute paleoclimatic data relating to dry periods when calcite speleothems are not deposited. In contrast, the dating of calcite speleothems in gypsum caves could identify former wet periods in arid zones.

  16. Does cutting a plaster window weaken its strength?

    Science.gov (United States)

    Patel, Nimesh; Wilson, Lance; Wansbrough, Guy

    2017-03-01

    A plaster window is usually created over a pressure area, or in some cases a wound or suture line. This can relieve pressure at the site, and provide an opportunity to change dressings, check on drainage, and inspect a wound or ulcer. There is concern that this can have an effect on its function to provide fracture stability, and weakens the plaster. The biomechanical effects of windowing on plaster strength were therefore investigated, as it has not previously been reported. A laboratory study was undertaken to compare the bending, kinking and torsion loads withstood by standardised Plaster of Paris (POP), Softcast and Fibreglass casts compared to those with a 60×40mm window fabricated in the centre at clinically defined endpoints using an Instron machine. The addition of a window significantly weakened the load to failure of POP; Fibreglass, and Softcast by 23.1% (473.1N); 25.9% (401.8N), and 29% (146.6N) respectively, during the 4-point bending tests. During the 3-point kinking tests, load to failure was reduced by 38.5% (297.8N); 35.3% (146.9N), and 51.5% (103.8N) respectively. All tests were checked for consistency and carried out in a single orthogonal plane for ease of comparison. The addition of a 60×40mm window to a cast made up of POP, Fibreglass or Softcast weakens the cast load to failure by up to 51% against a 3-point loading force. Though windowing of casts is necessary in certain situations, we advise precautions such as adding further layers of plaster to the window site, keeping the window as small as possible, and advising the patient of the increased risk of weakening and failure of the plaster so that they can take more care. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. DEVELOPMENT OF HYDRAULIC GYPSUM THAT CONTAINS CEMENTS THAT HAVE SULPHATED CLINKER PHASES

    Directory of Open Access Journals (Sweden)

    Mikheenkov Mikhail Arkad'evich

    2012-10-01

    Full Text Available In the article, the authors consider the feasibility of development of water-hardened gypsum that is capable of hardening in the water. The gypsum in question is made of the gypsum binding material, sulphated Portland cement, and granulated blast-furnace slag. The gypsum developed hereunder has a softening coefficient over 1 while the building gypsum content exceeds 75 %.

  18. Alabaster and Selenite Gypsum:I-Dehydration-Rehydration Comparison Studies

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Two types of gypsum raw materials, selenite and alabaster, were used to prepare dental stone (α-hemihydrate).Gypsum lumps (0.8~2.5 cm) were hydrothermally treated at 135, 160 and 180°C for 6, 2 and 1 h respectively.The physicochemical properties and composition characteristics of the α-hemihydrates prepared from selenite and alabaster raw gypsum were determined. The results indicated that both the selenite and alabaster raw gypsum show the same chemical and mineralogical composition of calcium sulphate dihydrate. They differs only in their microstructure, selenite raw gypsum exhibits perfect regular crystals while alabaster gypsum, on the other hand,exhibits irregular, large size and interlocked crystals. Selenite is more accessible to dehydration than alabaster raw gypsum. The α-hemihydrate samples prepared from alabaster raw gypsum showed a very short setting time and a lower compressive strength values in relation to that prepared from selenite gypsum. The compressive strength values of the all prepared samples were higher than that specified by A.D.A specification for dental use. To optimize the setting time of both products further studies are needed.

  19. The Material Behavior Of Plastered-Bamboo Wall Towards Lateral Loads

    OpenAIRE

    V. R. R. Hutubessy,; Hrc. Priyosulistyo

    2014-01-01

    This study determined the lateral resistance capacity of the plastered-bamboo wall. The test was carried out on three pieces of plastered-bamboo wall. The first was plastered-bamboo wall without bracing (DP-TB), second was plastered-bamboo wall using bamboo bracing (DP-BB), and the last is a plastered-bamboo wall which uses wiremesh bracing (DP-BK). The static load (monotonic) test method was used to determine the correlation between the lateral resistance and the deflection o...

  20. Auricular-Plaster Therapy for Treatment of IBS

    Institute of Scientific and Technical Information of China (English)

    敖学艳; 王宁

    2004-01-01

    @@ Irritable bowel syndrome (IBS), a disease of the digestive system related to mental factors, is clinically characterized by diarrhea (or alternation of diarrhea and constipation) and abdominal pain. In recent years, the authors have used auricular-plaster therapy plus pressing on the back-shu points to treat IBS, and obtained good therapeutic results.

  1. Roughness of surface of vacuum castings prepared in plaster moulds

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2011-07-01

    Full Text Available The results of researches on surface roughness of CuSn10 and CuSn5Zn5Pb5 bronzes and aluminum AlSi11 alloy vacuum castings prepared in plaster moulds are presented in this paper. Test samples were cut from stripe castings of dimensions 100x15x1 mm. Surfaces were carefully cleaned with use of soft brush than in ultrasonic washer and dried. Experimental castings were prepared in moulds made of two types of plaster. Cast temperatures were 1120 and 1200°C for bronzes and 700 and 800°C for silumin. Temperatures of the mould were 500 and 600°C for bronzes and 200 and 300°C for aluminum alloy. The roughness measurements were carried out with use of Hommelwerke Tester T1000. The average arithmetic deviation of roughness profile Ra, the ten-point height of irregularities Rz and maximum peak to valley height Rm, were measured.It can be stated, on the base of obtained results, that technology of casting in plaster moulds allows preparation of castings of very low roughness, average Ra=0,88÷1,74μm for bronzes and Ra=0,59÷0,83μm for aluminum alloys. Roughness of the surface depends in fact on the cast material. Type of plaster and casting parameters have negligible influence on it.

  2. [Treatment of persistent postmastectomy pain with 5% Lidocaine medicated plaster].

    Science.gov (United States)

    Cruto, M E; Baricocchi, E; Battistella, M; Bona, F; Giacoletto, G; Iacobellis, A; Moselli, N; Palomba, G; Sardo, E; Savojardo, M; Suita, L; Zocca, E; Debernardi, F

    2015-04-01

    Persistent postmastectomy pain (PPMP) syndrome is characterized by neuropathic pain that develops following surgery in breast cancer patients. The reported incidence of PPMP ranges between 30% and 50% and is estimated to increase as the number of women surviving cancer continues to rise. Though effective, today's drug treatments are poorly tolerated, limiting their use and reducing adherence to therapy. Since neuropathic pain is localized, international guidelines suggest that topical treatment with 5% Lidocaine medicated plaster either alone or combined with systemic drugs can be considered for pain management. In this retrospective study we reviewed the medical records of 11 patients treated with 5% lidocaine medicated plaster for moderate-to-severe PPMP at our institute between November 2013 and October 2014. Analysis showed that treatment with 5% Lidocaine medicated plaster, either alone or in combination with systemic drugs, achieved significant pain control already after the first week of therapy. The effectiveness and tolerability of 5% Lidocaine medicated plaster we observed suggests that it is a viable option in the management of PPMP.

  3. Plastering. Pre-Apprenticeship Phase 2 Training. Student Training Modules.

    Science.gov (United States)

    Hamblen, Ron

    These 20 Student Training Modules on plastering comprise one of nine sets of self-paced learning modules developed for Pre-Apprenticeship Phase 2 Training. (A companion instructor's guide is available separately as CE 031 569.) The modules are designed to impart trade knowledge and skills to the student. Each module contains some or all of the…

  4. No local recurrence of enchondroma after curettage and plaster filling.

    NARCIS (Netherlands)

    Gaasbeek, R.D.A.; Rijnberg, W.J.; Loon, C.J.M. van; Meyers, H.; Feith, R.

    2005-01-01

    INTRODUCTION: The most common treatment of enchondromas is curettage (with or without adjuvant therapy) followed by cancellous bone grafting. To avoid donor-site morbidity of the iliac crest, we applied plaster of Paris as a bone defect filler after curettage of enchondromas. MATERIALS AND METHODS:

  5. Analysis of transport and crystallisation of salts in restoration plasters

    NARCIS (Netherlands)

    Hees, R.P.J. van; Lubelli, B.

    2002-01-01

    For the understanding of the salt crystallisation mechanism in restoration plasters, the understanding of water (moisture) transport is essential, as it is the influence of salts on the water transport. More specifically the drying behaviour, i.e. the moisture / salt transport and distribution durin

  6. The Material Behavior Of Plastered-Bamboo Wall Towards Lateral Loads

    Directory of Open Access Journals (Sweden)

    V. R. R. Hutubessy,

    2014-01-01

    Full Text Available This study determined the lateral resistance capacity of the plastered-bamboo wall. The test was carried out on three pieces of plastered-bamboo wall. The first was plastered-bamboo wall without bracing (DP-TB, second was plastered-bamboo wall using bamboo bracing (DP-BB, and the last is a plastered-bamboo wall which uses wiremesh bracing (DP-BK. The static load (monotonic test method was used to determine the correlation between the lateral resistance and the deflection of plastered-bamboo wall. The monotonic testing was only conducted until the load has experience 20% decrease from peak load. The test results showed that the plastered-bamboo wall using wiremesh bracing had the peak load capacity, energy dissipation, and higher ductility than the plastered-bamboo wall using bamboo bracing. Elastic stiffness of the plastered-bamboo wall using bamboo bracing was 1.27 greater than plastered-bamboo wall using wiremesh bracing. The ultimate load resulted from the experiment of the plastered-bamboo wall with either bamboo or additional wiremeshbracingwas 25.52 kN and 26.37 kN or two times greater than the results of an analysis of the flexural failure based on Subedi method (1991 which was 14.39 kN.

  7. Physical, mechanical, and durability properties of gypsum-Portland cement-natural pozzolan blends

    National Research Council Canada - National Science Library

    Colak A

    2001-01-01

    This paper deals with the effect of gypsum Portland cement and gypsum Portland cement natural pozzolan ratios on the physical, mechanical, and durability properties of gypsum Portland cement natural pozzolan blends...

  8. Health survey in gypsum mines in India

    Directory of Open Access Journals (Sweden)

    Nandi Subroto

    2009-01-01

    Full Text Available Background: Mining is a hazardous occupation in which workers are exposed to adverse conditions. In India, gypsum mining is mainly carried out in the state of Rajasthan, which contributes about 99% of the total production. Objective: The present study was carried out in 12 different gypsum mines in Rajasthan state to determine the health status of the miners. Materials and Methods: One hundred and fifty workers engaged in mining activities were included in the study and their health status was compared with that of 83 office staff of the same mines. The health status of the employees was evaluated using a standardized medical questionnaire and pulmonary function testing. Statistical Analysis: The unpaired ′t′ test was used to determine whether there was any significant difference between the miners and the controls and the chi-square test to compare the prevalences of various respiratory impairments in workers with that in controls; we also examined the differences between smokers and nonsmokers. Results: Our findings show that the literacy rate is low (42% among the miners. Pulmonary restrictive impairment was significantly higher amongst smokers as compared to nonsmokers in both miners and controls. Hypertension (22.6%, diabetes (8.8%, and musculoskeletal morbidity (8% were the common diseases in miners. Conclusion: This study shows that there is high morbidity amongst miners, thus indicating the need for regular health checkups, health education, use of personal protective devices, and engineering measures for control of the workplace environment.

  9. Geology of the Gypsum Gap quadrangle, Colorado

    Science.gov (United States)

    Cater, Fred W.

    1953-01-01

    The Gypsum Gap quadrangle is one eighteen 7 1/2-minute quadrangles covering the principal carnotite-producing area of southwestern Colorado. The geology of these quadrangles was mapped by the U.S. Geological Survey for the Atomic Energy Commission as part of a comparative study of carnotite deposits. The rocks exposed in the eighteen quadrangles consist of crystalline rocks of pre-Cambrian age and sedimentary rocks that range in age from late Paleozoic to Quaternary. Over much of the area the sedimentary rocks are flat lying, but in places the rocks are disrupted by high-angle faults, and northwest-trending folds. Conspicuous among the folds are large anticlines having cores of intrusive salt and gypsum. Most of the carnotite deposits are confined to the Salt Wash sandstone member of the Jurassic Morrison formation. Within this sandstone, most of the deposits are spottily distributed through a arcuate zone known as the "Uravan Mineral Belt". Individual deposits range in size from irregular masses containing only a few tons of ore to large, tabular masses containing many thousands of tons. The core consists largely of sandstone selectively impregnated and in part replaced by uranium and vanadium minerals. Most of the deposits appear to be related to certain sedimentary structures in sandstones of favorable composition.

  10. Flue gas desulfurization gypsum and fly ash

    Energy Technology Data Exchange (ETDEWEB)

    1992-05-01

    The Cumberland Fossil Plant (CUF) is located in Stewart County, Tennessee, and began commercial operation in 1972. This is the Tennessee Valley Authority`s newest fossil (coal-burning) steam electric generating plant. Under current operating conditions, the plant burns approximately seven million tons of coal annually. By-products from the combustion of coal are fly ash, approximately 428,000 tons annually, and bottom ash, approximately 115,000 tons annually. Based on historical load and projected ash production rates, a study was initially undertaken to identify feasible alternatives for marketing, utilization and disposal of ash by-products. The preferred alternative to ensure that facilities are planned for all by-products which will potentially be generated at CUF is to plan facilities to handle wet FGD gypsum and dry fly ash. A number of different sites were evaluated for their suitability for development as FGD gypsum and ash storage facilities. LAW Engineering was contracted to conduct onsite explorations of sites to develop information on the general mature of subsurface soil, rock and groundwater conditions in the site areas. Surveys were also conducted on each site to assess the presence of endangered and threatened species, wetlands and floodplains, archaeological and cultural resources, prime farmland and other site characteristics which must be considered from an environmental perspective.

  11. A new portable vibrator for plaster pouring: effect on the marginal fit at cylinder-abutment

    Directory of Open Access Journals (Sweden)

    Pâmela Cândida Aires Ribas de Andrade

    2012-10-01

    Full Text Available OBJECTIVE: The aim of this study was to test a new portable vibrator for plaster pouring (developed for this purpose, comparing the effect of its use on the accuracy of working cast of implant-supported restorations to the conventional vibrator. MATERIAL AND METHODS: From a master cast with 2 implants, 30 transfer moldings were made randomly and divided into three groups: Group I (GI: pouring performed in an outsourced dental laboratory with conventional plaster vibrator (10 casts, Group II (GII: pouring performed in the laboratory of the Federal University of Santa Catarina (UFSC with conventional plaster vibrator (10 casts and Group III (GIII: pouring performed with the portable vibrator fabricated for this study (10 casts. The position of the analogue and marginal adaptation of the infrastructure were verified by testing the single screw on the master model and on the working model. The measurement of misfit was blindly performed with a precision microscope and analyzing unit, Quadra-Check 200. The data were statistically analyzed by analysis of variance (ANOVA and the Holm-Sidak test (α=0.05. RESULTS: Means±standard deviations were as follows: GI: 19.19±4.73 µm; GII: 21.72±5.41 µm; GIII: 13.5±2.39 µm (P<0.05, with GIII significantly lower as compared to the other groups. CONCLUSION: Within the limitations of this study, it was concluded that a greater accuracy of working cast was achieved when a portable vibrator was used for casting molds.

  12. Raman spectroscopy of shocked gypsum from a meteorite impact crater

    Science.gov (United States)

    Brolly, Connor; Parnell, John; Bowden, Stephen

    2017-07-01

    Impact craters and associated hydrothermal systems are regarded as sites within which life could originate on Earth, and on Mars. The Haughton impact crater, one of the most well preserved craters on Earth, is abundant in Ca-sulphates. Selenite, a transparent form of gypsum, has been colonized by viable cyanobacteria. Basement rocks, which have been shocked, are more abundant in endolithic organisms, when compared with un-shocked basement. We infer that selenitic and shocked gypsum are more suitable for microbial colonization and have enhanced habitability. This is analogous to many Martian craters, such as Gale Crater, which has sulphate deposits in a central layered mound, thought to be formed by post-impact hydrothermal springs. In preparation for the 2020 ExoMars mission, experiments were conducted to determine whether Raman spectroscopy can distinguish between gypsum with different degrees of habitability. Ca-sulphates were analysed using Raman spectroscopy and results show no significant statistical difference between gypsum that has experienced shock by meteorite impact and gypsum, which has been dissolved and re-precipitated as an evaporitic crust. Raman spectroscopy is able to distinguish between selenite and unaltered gypsum. This shows that Raman spectroscopy can identify more habitable forms of gypsum, and demonstrates the current capabilities of Raman spectroscopy for the interpretation of gypsum habitability.

  13. Hydrogen sulfide release from dairy manure storages containing gypsum bedding

    Science.gov (United States)

    Recycled gypsum products can provide a cost-effective bedding alternative for dairy producers. Manufacturers report reduced odors, moisture and bacteria in the stall environment when compared to traditional bedding. Gypsum provides a sulfate source that can be converted to hydrogen sulfide under ana...

  14. Modification of FGD gypsum in hydrothermal mixed salt solution

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-qin; WU Zhong-biao

    2006-01-01

    A novel utilization way of the sludge from wet calcium-based flue gas desulfurization (FGD) processes has been developed in this paper. This study focused on the conversion of the FGD gypsum into α-hemihydrate calcium sulfate by a hydrothermal salt solution method at atmospheric pressure. Experimental study has been carried out in a batch reactor. Qualitative and quantitative analyses were made by DSC/TG thermal analysis, SEM, XRD, metalloscope and chemical analysis. The experimental results showed that the modification of FGD gypsum was controlled by the dissolution and recrystallization mechanisms. With the introduction of FGD gypsum the salt solution was supersaturated, then crystal nucleus of α-hemihydrate calcium sulfate were produced in the solution. With the submicroscopic structure of FGD gypsum crystal changed, the crystal nucleus grew up into α-hemihydrate calcium sulfate crystals. Thus, the modification of FGD gypsum was fulfilled.

  15. Gypsum plasterboards enhanced with phase change materials: A fire safety assessment using experimental and computational techniques

    Directory of Open Access Journals (Sweden)

    Kolaitis Dionysios I.

    2013-11-01

    Full Text Available Phase Change Materials (PCM can be used for thermal energy storage, aiming to enhance building energy efficiency. Recently, gypsum plasterboards with incorporated paraffin-based PCM blends have become commercially available. In the high temperature environment developed during a fire, the paraffins, which exhibit relatively low boiling points, may evaporate and, escaping through the gypsum plasterboard's porous structure, emerge to the fire region, where they may ignite, thus adversely affecting the fire resistance characteristics of the building. Aiming to assess the fire safety behaviour of such building materials, an extensive experimental and computational analysis is performed. The fire behaviour and the main thermo-physical physical properties of PCM-enhanced gypsum plasterboards are investigated, using a variety of standard tests and devices (Scanning Electron Microscopy, Thermo Gravimetric Analysis, Cone Calorimeter. The obtained results are used to develop a dedicated numerical model, which is implemented in a CFD code. CFD simulations are validated using measurements obtained in a cone calorimeter. In addition, the CFD code is used to simulate an ISO 9705 room exposed to fire conditions, demonstrating that PCM addition may indeed adversely affect the fire safety of a gypsum plasterboard clad building.

  16. Effect of background electrolytes on gypsum dissolution

    Science.gov (United States)

    Burgos-Cara, Alejandro; Putnis, Christine; Ruiz-Agudo, Encarnacion

    2015-04-01

    Knowledge of the dissolution behaviour of gypsum (CaSO4· 2H2O) in aqueous solutions is of primary importance in many natural and technological processes (Pachon-Rodriguez and Colombani, 2007), including the weathering of rocks and gypsum karst formations, deformation of gypsum-bearing rocks, the quality of drinking water, amelioration of soil acidity, scale formation in the oil and gas industry or measurement of water motion in oceanography. Specific ions in aqueous solutions can play important but very different roles on mineral dissolution. For example, the dissolution rates and the morphology of dissolution features may be considerably modified by the presence of the foreign ions in the solution, which adsorb at the surface and hinder the detachment of the ions building the crystal. Dissolution processes in the aqueous environment are closely related to the rearrangement of water molecules around solute ions and the interaction between the solvent molecules themselves. The rearrangement of water molecules with respect to solute species has been recognized as the main kinetic barrier for crystal dissolution in many systems (Davis, 2000; De Yoreo and Dove 2004; Wasylenki et al. 2005). Current research suggest that the control that electrolytes exert on water structure is limited to the local environment surrounding the ions and is not related to long-range electric fields emanating from the ions but results from effects associated with the hydration shell(s) of the ions (Collins et al. 2007) and the ions' capacity to break or structure water (i.e. chaotropic and kosmotropic ions, respectively). These effects will ultimately affect the kinetics of crystal dissolution, and could be correlated with the water affinity of the respective background ions following a trend known as the lyotropic or Hofmeister series (Kunz et al. 2004; Dove and Craven, 2005). In situ macroscopic and Atomic Force Microscopy (AFM) flow-through dissolution experiments were conducted at a

  17. Contractility of Plaster Mould for Arc Spraying Rapid Tooling%电弧喷涂快速制模用石膏母模的收缩性

    Institute of Scientific and Technical Information of China (English)

    刘峰; 陈巧; 杨伟

    2012-01-01

    对比试验研究了水膏比、水玻璃和羧甲基纤维素加入量对电弧喷涂快速制模用石膏母模收缩性的影响.结果表明,随着水玻璃和羧甲基纤维索加入量的增加,收缩率呈现增加的趋势;在同一水青比下,收缩率变化出现一个“峰值”,最小收缩率出现时羧甲基纤维素的加入量在0.15%~0.25%之间.%Influences of water-gypsum ratio, soluble glass and CMC on the contractility of the piaster mould for the arc spraying rapid tooling were investigated. The experimental results show thai contractility of plaster mould is increased with the increase of the content of the sodium silicate and CMC, and peak value can be oberved in the contractility at a fixed water-gypsum ratio. In addition. the minimum contractility appears with 0. 15%- 0.25% CMC.

  18. Water defluoridation using Malawi’s locally sourced gypsum

    Science.gov (United States)

    Masamba, W. R. L.; Sajidu, S. M.; Thole, B.; Mwatseteza, J. F.

    Free fluoride levels above the WHO guideline maximum value of 1.5 mg/l have been reported in several parts of Malawi. Dental fluorosis has also been observed in the same areas such that search for local defluoridation techniques has become important in the country. The present research intended to determine the potential of using Malawi gypsum in defluoridation, identify the best pre-treatment of the gypsum and optimum conditions under which effective water defluoridation with the gypsum may be obtained. Laboratory experiments were carried out to explore defluoridation of drinking water using locally sourced gypsum and gypsum calcined at high temperatures. A 400 °C calcined phase of gypsum gave the highest defluoridation capacity of 67.80% compared to raw (uncalcined) gypsum, 200, 300 and 500 °C calcined phases. Powder X-ray diffraction (PXRD) pattern of the 400 °C phase revealed existence of less crystalline CaSO 4 that was thought to be responsible for such relatively high defluoridation capacity. The dependence of the fluoride removal by the 400 °C calcined phase on other drinking water quality parameters was assessed by simple correlation analysis. Reaction kinetics and mechanisms of fluoride removal by the materials were also investigated. It was found that ion exchange was the dominant mechanism through which fluoride was removed from water by the materials.

  19. Carbonate speleothems from western Mediterranean gypsum karst: palaeoclimate implications

    Science.gov (United States)

    Columbu, Andrea; Drysdale, Russell; Woodhead, Jon; Chiarini, Veronica; De Waele, Jo; Hellstrom, John; Forti, Paolo; Sanna, Laura

    2016-04-01

    Gypsum caves are uncommon environments for carbonate speleothems (cave deposits). Contrary to limestone caves, the only source of non-atmospheric carbon is from biogenic CO2 produced by the overlying soils. Enhanced CO2 content in soils is in turn related with climate, where warm temperatures and high humidity favour plant activity .().....(Fairchild and Baker, 2012). Although poorly decorated, the exploration of northern Italian and Spanish gypsum karst systems reveals the existence of several generations of carbonate speleothems, which have been dated with the U-Th series method .()......(Hellstrom, 2003; Scholz and Hoffmann, 2008). Their ages coincide with current and previous two interglacials (MIS 1, 5e and 7e and Greenland interstadials (GIS) 19, 20, 21 and 24. Considering that these periods are amongst the most pronounced warm-wet pulsations over the last 250,000 ...(Martrat et al., 2007; NGRIP, 2004), and that CO2 has a fundamental role in this karst process, this study explores the climate-driven hydrogeological conditions necessary to trigger carbonate deposition in gypsum voids. The further correlation with sapropel events 5, 4, 3 and 1, considered symptomatic of enhanced rainfall across the whole Mediterranean basin .(.)(Emeis et al., 1991), highlights the importance of flow-rate in the fracture network and infiltration of meteoric water into the caves. The combination of high CO2 and a phreatic status of the fracture network is thus indispensable for the formation of carbonate speleothems in gypsum karst. This condition appears to be triggered by periods of orbital precession minimum, when the monsoonal activity peaked in the Atlantic area. Stable oxygen isotope signatures suggest that the speleothems did not grow during any interglacial-glacial or main interstadial-stadial transitions, confirming that variations from optimum climate conditions may hamper the formation of this category of speleothems. New speleological exploration and sampling campaign

  20. Sustainable Uses of FGD Gypsum in Agricultural Systems: Introduction.

    Science.gov (United States)

    Watts, Dexter B; Dick, Warren A

    2014-01-01

    Interest in using gypsum as a management tool to improve crop yields and soil and water quality has recently increased. Abundant supply and availability of flue gas desulfurization (FGD) gypsum, a by-product of scrubbing sulfur from combustion gases at coal-fired power plants, in major agricultural producing regions within the last two decades has attributed to this interest. Currently, published data on the long-term sustainability of FGD gypsum use in agricultural systems is limited. This has led to organization of the American Society of Agronomy's Community "By-product Gypsum Uses in Agriculture" and a special collection of nine technical research articles on various issues related to FGD gypsum uses in agricultural systems. A brief review of FGD gypsum, rationale for the special collection, overviews of articles, knowledge gaps, and future research directions are presented in this introductory paper. The nine articles are focused in three general areas: (i) mercury and other trace element impacts, (ii) water quality impacts, and (iii) agronomic responses and soil physical changes. While this is not an exhaustive review of the topic, results indicate that FGD gypsum use in sustainable agricultural production systems is promising. The environmental impacts of FGD gypsum are mostly positive, with only a few negative results observed, even when applied at rates representing cumulative 80-year applications. Thus, FGD gypsum, if properly managed, seems to represent an important potential input into agricultural systems. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  1. Alfalfa Responses to Gypsum Application Measured Using Undisturbed Soil Columns

    Directory of Open Access Journals (Sweden)

    Rebecca Tirado-Corbalá

    2017-07-01

    Full Text Available Gypsum is an excellent source of Ca and S, both of which are required for crop growth. Large amounts of by-product gypsum [Flue gas desulfurization gypsum-(FGDG] are produced from coal combustion in the United States, but only 4% is used for agricultural purposes. The objective of this study was to evaluate the effects of (1 untreated, (2 short-term (4-year annual applications of gypsum totaling 6720 kg ha−1, and (3 long-term (12-year annual applications of gypsum totaling 20,200 kg ha−1 on alfalfa (Medicago sativa L. growth and nutrient uptake, and gypsum movement through soil. The study was conducted in a greenhouse using undisturbed soil columns of two non-sodic soils (Celina silt loam and Brookston loam. Aboveground growth of alfalfa was not affected by gypsum treatments when compared with untreated (p > 0.05. Total root biomass (0–75 cm for both soils series was significantly increased by gypsum application (p = 0.04, however, increased root growth was restricted to 0–10 cm depth. Soil and plant analyses indicated no unfavorable environmental impact from of the 4-year and 12-year annual application of FGDG. We concluded that under sufficient water supply, by-product gypsum is a viable source of Ca and S for land application that might benefit alfalfa root growth, but has less effect on aboveground alfalfa biomass production. Undisturbed soil columns were a useful adaptation of the lysimeter method that allowed detailed measurements of alfalfa nutrient uptake, root biomass, and yield and nutrient movement in soil.

  2. Efficacy of a new blister prevention plaster under tropical conditions.

    Science.gov (United States)

    Sian-Wei Tan, Shani; Kok, Swee Kuan; Lim, Jeremy Khim Yong

    2008-01-01

    To survey the incidence of blister formation in a group of military recruits and to determine the efficacy of a new commercially available blister prevention plaster (Blist-O-Ban). Questionnaires were completed by 100 male recruits, and the same 100 were entered into a field trial. Due to illness, 2 did not complete the study. Premarch foot condition was documented. Each participant acted as his own control. Foot side and plaster site were randomly selected, and plasters were applied according to a strict protocol. Participants were re-examined for blisters after a 16-km hike with pack, and the condition of the feet was documented. A chi2 test was used to analyze the results. Ninety-eight volunteers with 101 Blist-O-Ban application sites participated. Twenty-seven participants developed a total of 46 blisters. Heel and toe blisters accounted for more than half of all blisters. None of the bandage application sites developed blisters, and 99 out of 101 bandages remained well adhered to the application sites. When applied according to strict protocol, the new blister prevention bandage remained well-adhered to application sites and prevented the formation of foot blisters even in humid tropical conditions.

  3. The thermal analysis and derivative bronzes cast to plaster moulds

    Directory of Open Access Journals (Sweden)

    B. Pisarek

    2009-07-01

    Full Text Available It plaster moulds gets casted the alloys of following metals: Al, Cu, Ag, Au in precise and artistic founding. The investigation of the crys-tallization of bronzes in hot plaster moulds the method of the thermal analysis and derivative (TDA was not realized out so far. Probe TDAg and tripod enabling the execution of measurements on inductive casting machine INDUTHERM-VC 500D were designed for this technology especially. It was confirmed that one the method TDA can identify the crystallization process of the bronze in hot plaster moulds. The investigations of the superficial distribution of the concentration of elements in the microstructure of the studied grades of the bronze on X-ray microanalizer were conducted. It results that they be subject to in bronze CuSn10-C (B10 and the CuSn5Zn5Pb5-C (B555 of strong microsegregation from conducted investigations: Pb, Sn and Sb. The single separates of intermetallic phase κ was identified in the bronze B10 rich first of all in Zn, Sn, Sb and Fe, and two intermetallic phase, one rich were identified in the bronze B555 first of all in Zn, Sb, (Nor, Fe and second rich in Sn, Sb, (Nor, Fe. The most homogeneous microstructure from the bronze CuAl10Fe5Ni5-C (BA1055 is characterizes among the studied grades of the bronze in the cast state.

  4. Calculation of k factor function for the carbonation process of lime-based plasters

    Science.gov (United States)

    Pavlíková, Milena; Pokorný, Jaroslav; Pavlík, Zbyšek

    2017-07-01

    The carbonation process of prepared lime plaster and lime based plaster with pozzolana active metakaolin is performed in an accelerated test arrangement. The depth of carbonation head is determined using colorimetric method and FTIR spectroscopy. Based on experimental data of carbonation head, time dependent k factor function is calculated that points to the decelerated and retarded propagation of the carbonation process due to metakaolin used in plaster composition.

  5. Behavior of plasters on the modern heat-effective exterior walls of buildings (rus

    Directory of Open Access Journals (Sweden)

    Babkov V.V.

    2012-12-01

    Full Text Available Physical and mechanical characteristics, the most significant for the plasters with regard to the features of their behavior as the coating of building faces were evaluated. Results of quantitative estimation of stresses in the plaster layers on surfaces of different stiffness due to the plaster shrinkage are given. It is shown that with a decrease of the surface modulus of elasticity, stresses in the plaster coating are decreased either due to reduction of the effect of its deformations’ constraint. By analysis and with experiments it is proved, that the main factor evaluating the ultimate extensibility of the mortar is its viscoelasticity modulus, while mortar strength increase involves its stresses increase.

  6. Deformability of plastering compositions in design solutions of modern thermal protective exterior walls

    Directory of Open Access Journals (Sweden)

    R.R. Vakhitov

    2013-04-01

    Full Text Available In recent years, appearance of new constructive decisions for multilayer thermal efficient walls in the practice of design and construction caused the increasing use of protective and decorative plaster compositions. Comprehensive protective plaster systems nowadays are used in the facade insulation systems as a protective layer on the surface of polystyrene foam or mineral wool boards, forming the insulating layer to the outer walls of concrete blocks. They are also used for exterior finish of walls made of gas-concrete blocks, plastering the brickwork of the buildings operated by rehabilitation, in particular, apartment houses of old mass series. The problem of ensuring durability of thermal efficient external walls with the use of protective and decorative plaster systems were identified in this article. The factors, affecting the resistance of facade plasters to the action of external conditions in operating process were considered. The weaknesses in the necessary characteristics of plaster mixtures provided by material manufacturers are revealed. The existing methods for determining crack resistance of plaster compositions are monitored. The author's method of determining the maximum stretch of plaster compositions is given. The article presents tests results of various plaster compositions, confirming the effectiveness of the proposed method.

  7. Plaster of Paris-Short History of Casting and Injured Limb Immobilzation.

    Science.gov (United States)

    Szostakowski, B; Smitham, P; Khan, W S

    2017-01-01

    Various materials have been used since ancient times to help immobilise fractures. In this review, we discuss the history and developments of these materials as well as plaster of Paris. There has been a recent trend away from non-operative management of fractures, and skills in the use of plaster of Paris are declining. For the successful treatment of patients, it is important to appreciate how plaster works, how it should be used, and what can go wrong. In this review, we also discuss principles of applications and complications of plaster of Paris.

  8. Lidocaine/tetracaine medicated plaster: in minor dermatological and needle puncture procedures.

    Science.gov (United States)

    Croxtall, Jamie D

    2010-11-12

    The lidocaine/tetracaine medicated plaster comprises a lidocaine/tetracaine 70 mg/70 mg patch and a controlled heat-assisted drug delivery pod that increases the diffusion of lidocaine and tetracaine into the dermis. Following a 1-hour application period, systemic absorption of lidocaine or tetracaine from the plaster was minimal. The lidocaine/tetracaine medicated plaster provided effective pain relief for adult (including elderly) patients undergoing minor dermatological procedures and for adult and paediatric patients undergoing vascular access procedures. In randomized, double-blind clinical trials, patient-reported median pain scores were significantly lower with the lidocaine/tetracaine medicated plaster than with an identical plaster containing placebo in patients undergoing minor dermatological or vascular access procedures. Furthermore, patient-reported median pain scores were significantly lower with the lidocaine/tetracaine medicated plaster than with a lidocaine/prilocaine cream in patients undergoing vascular access procedures. In a large, randomized, double-blind trial in paediatric patients undergoing venipuncture, the overall incidence of pain was significantly lower with the lidocaine/tetracaine medicated plaster than with a lidocaine/prilocaine plaster. The lidocaine/tetracaine medicated plaster was well tolerated, with the most frequent treatment-related adverse events resolving spontaneously.

  9. Plaster of Paris–Short History of Casting and Injured Limb Immobilzation

    Science.gov (United States)

    Szostakowski, B.; Smitham, P.; Khan, W.S.

    2017-01-01

    Various materials have been used since ancient times to help immobilise fractures. In this review, we discuss the history and developments of these materials as well as plaster of Paris. There has been a recent trend away from non-operative management of fractures, and skills in the use of plaster of Paris are declining. For the successful treatment of patients, it is important to appreciate how plaster works, how it should be used, and what can go wrong. In this review, we also discuss principles of applications and complications of plaster of Paris. PMID:28567158

  10. Gypsum crystals in the inner shelf sediments off Maharashtra, India

    Digital Repository Service at National Institute of Oceanography (India)

    Hashimi, N.H.; Ambre, N.V.

    Gypsum crystals have been found in the inner shelf silty clay/clayey silt off the Maharashtra Coast between Vengurla and Bombay. Generally these occur as euhedral single or twinned crystals of selenite. Very often shells are found embedded within...

  11. IMPACT OF VARIOUS ADDITIVES ONTO MORPHOLOGY OF GYPSUM CRYSTALS

    OpenAIRE

    Ustinova Yuliya Valer'evna; Sivkov Sergey Pavlovich; Barinova Ol'ga Pavlovna; Sanzharovskiy Aleksandr Yur'evich

    2012-01-01

    Nowadays, functional additives represented by multiple classes of substances and compounds, including polymers of different origin, are available for introduction into dry mixtures based on gypsum binders. However, their impact onto the growth and formation of calcium sulfate dihydrate (CaSO∙2HO) crystals generated in the course of hardening of gypsum binders is not quite clear. Therefore, the objective of the research was to analyze the processes of growth and formation of calcium sulfate di...

  12. PCM-enhanced lime plasters for vernacular and contemporary architecture

    Science.gov (United States)

    Theodoridou, Magdalini; Kyriakou, Loucas; Ioannou, Ioannis

    2016-04-01

    In 1997, the European Union (EU) pledged to reduce the amount of greenhouse gas emissions by 20% below the levels of 1990 by the end of 2020. In recent years it has become evident that, in order to reach that goal, EU Member States must take measures to encourage sustainability in the building industry, which is a major energy consumer. Such measures should involve the use of innovative, environmentally friendly materials and methods in new constructions, as well as the renovation of existing properties by upgrading their current state of energy efficiency. Phase Change Materials (PCMs) have the ability to absorb and release thermal energy, in the form of latent heat, during the melting or solidifying processes respectively. Thus, they may be used as additives in the production of thermally efficient composite building materials. A PCM-enhanced plaster is a heat storage medium combining an appropriate PCM with a cementitious or non-cementitious matrix to produce a low-cost thermal storage material with structural and thermostatic properties. Although innovative technologies, such as PCMs, have certainly contributed to the boost in the evolution of the building materials industry in recent years, a significant proportion of these technologies and practices have not yet been fully exploited in materials based on traditional principles. This paper focuses on the design and production of novel cementless PCM-enhanced lime plasters, in line with the traditional production technology of lime composites. The new plasters are produced using either hydrated or natural hydraulic lime binder, crushed calcarenite sand (0-2 mm) and commercial microencapsulated PCM in powder form (5% w/w of solids). Results from comparative tests between reference mixtures and mixtures with the addition of PCM, carried out 28, 56 and 90 days after laboratory production, prove the potential of PCMs in enhancing the thermal performance of traditional lime-based composites. The modified composites

  13. Two distinctive new species of Commicarpus (Nyctaginaceae) from gypsum outcrops in eastern Ethiopia

    DEFF Research Database (Denmark)

    Friis, Ib; Gilbert, Michael G.; Weber, Odile;

    2016-01-01

    During field trips in 2013 and 2014, two distinctive plants belonging to the genus Commicarpus were collected in the Lele Hills, Bale Zone, eastern Ethiopia, on outcrops of sedimentary rock belonging to the Gorrahei Formation with high contents of gypsum. The plants are here described as two new...... in Commicarpus, being a small self-supporting shrub to 0.8 (– 1) m high. Both new species occur in small populations with restricted distribution; models based on the available information show that the potential distribution is also restricted. C. macrothamnus is here evaluated as Vulnerable (VU), while C....... leleensis, only known from the type, should remain Data Deficient (DD). Outcrops of gypsum with restricted-range species are well known from eastern Ethiopia and Somalia, but the locality with the two new species of Commicarpus is the most north-western and one of the highest sites recorded so far...

  14. Lightened plaster: alternative solutions to cellular solids addition

    Directory of Open Access Journals (Sweden)

    Del Río, M.

    2004-09-01

    Full Text Available The following paper pretends to analyze different processes in order to lightweighters gypsum as an alternative way at the cellular fillers addition, in order to establish the most suitable ones for the manufacture of plasterboard. Outstanding the process which uses foamings addition to lighten gypsum uses nowdays only to manufacture cellular concrete.

    En este artículo se presenta el análisis de diferentes procedimientos para aligerar la escayola, como alternativas a la adición de sólidos celulares, determinando los más adecuados para la realización de prefabricados. Dentro de estos procedimientos cabe destacar la adición de espumantes, hasta ahora sólo utilizados para la fabricación de hormigones celulares.

  15. Effect of paint on vapour resistivity in plaster

    Directory of Open Access Journals (Sweden)

    de Villanueva, L.

    2008-12-01

    Full Text Available The vapour resistivity of plaster coatings such as paint and their effectiveness as water repellents were studied in several types of plaster. To this end, painted, unpainted and pigmented specimens were tested. Experimental values were collected on diffusion and vapour permeability, or its inverse, water vapour resistivity.The data obtained were very useful for evaluating moisture exchange between plaster and the surrounding air, both during initial drying and throughout the life of the material. They likewise served as a basis for ensuring the proper evacuation of water vapour in walls, and use of the capacity of the porous network in plaster products to regulate moisture content or serve as a water vapour barrier to avoid condensation.Briefly, the research showed that pigments, water-based paints and silicon-based water repellents scantly raised vapour resistance. Plastic paints, enamels and lacquers, however, respectively induced five-, ten- and twenty-fold increases in vapour resistivity, on average.Se estudia el fenómeno de la resistividad al vapor de los de yeso y el efecto impermeabilizante que producen los recubrimientos de pintura sobre diversos tipos de yeso y escayola. Para ello, se ensayan probetas desnudas y recubiertas con distintos tipos de pintura, así como coloreados en masa. Se obtienen valores experimentales de la difusividad o permeabilidad al vapor o su inverso la resistividad al vapor de agua.Los datos obtenidos son muy útiles para valorar el fenómeno del intercambio de humedad entre el yeso y el ambiente, tanto durante el proceso de su secado inicial, como en el transcurso de su vida. Así como para disponer soluciones adecuadas para la evacuación del vapor de agua a través de los cerramientos, para utilizar la capacidad de regulación de la humedad, que proporciona el entramado poroso de los productos de yeso, o para impedir el paso del vapor de agua y evitar condensaciones.Como resumen de la investigación, se

  16. Development of Biodegradable Nanosheets as Nano-adhesive Plasters

    Institute of Scientific and Technical Information of China (English)

    Shinji; Takeoka; Yosuke; Okamura; Toshinori; Fujie; Yoshihito; Fukui

    2007-01-01

    1 Results A nano-adhesive plaster is a biodegradable polymeric sheet with nanometer thickness; e.g.,one side is adhesive to a wound and the other side has high surface compatibility as biomaterial application.We proposed three kinds of polymeric nanosheets; the first is a sheet with ca.5 nm thickness made by cross-linking of human serum albumin (HSA) absorbed on a patterned octadecyltrimethoxysilane monolayer,the second is a nanosheet with ca.100 nm thickness prepared by thermal fusion of biodegradable P...

  17. Thermal testing and numerical simulation of gypsum wallboards incorporated with different PCMs content

    Energy Technology Data Exchange (ETDEWEB)

    Borreguero, Ana M.; Luz Sanchez, M.; Valverde, Jose Luis; Carmona, Manuel; Rodriguez, Juan F. [Department of Chemical Engineering, University of Castilla - La Mancha, Av. Camilo Jose Cela s/n, 13004 Ciudad Real (Spain)

    2011-03-15

    A mathematical model based on the Fourier heat conduction equation for one dimension was developed. The complexity of the mathematical solution of this stiff set of differential equations that use boundary conditions that move with the solid-liquid interface was simplified by using an apparent heat capacity (c{sub p}{sup ap}) dependent on temperature and obtained by Modulated Differential Scanning Calorimetry (MDSC). The performance of this model was confirmed by using a home-made experimental installation for the thermal characterization of solid materials. Theoretical curves obtained for gypsum blocks with three different contents of phase change materials (PCMs) were in agreement with experimental ones, indicating that this thermal process can be reproduced theoretically by using the c{sub p}{sup ap} of each block and a unique thermal conductivity of the pure gypsum. The other physical and thermal properties were taken from literature or supplied by the manufacturers. Results also indicated that the higher the PCM content, the higher the energy storage capacity of the wallboard and the lower the wall temperature variation. Furthermore, it was found that a block containing a 5 wt.% of microcapsule allows the reduction of gypsum thickness by 8.5%, maintaining the same insulating effect. Thus, these kind of material can be used to improve comfort, save energy in buildings and even reduce the weight of wallboards. (author)

  18. The performance of a restoration plaster in the field: Investigation and monitoring of two case studies

    NARCIS (Netherlands)

    Lubelli, B.; Hees, R.P.J. van; Groot, C.J.W.P.

    2005-01-01

    A large number of restoration plasters, especially developed for salt loaded substrates, have been introduced on the market in the last decades. The performance of these plasters in the field is not always satisfactory. The reasons of the failures may be found in the severity of the exposure conditi

  19. Salt transport and crystallization in plaster layers: A nuclear magnetic resonance study

    NARCIS (Netherlands)

    Petkovic, J.; Pel, L.; Huinink, H.P.; Kopinga, K.; Hees, R.P.J. van

    2005-01-01

    The durability and performance of specially developed restoration plasters or renders, are not always as good as expected. Salt crystallization is one of the causes of the observed degradation processes. To understand these processes in more detail, we investigated whether transport in the plasters

  20. 3-D Wizardry: Design in Papier-Mache, Plaster, and Foam.

    Science.gov (United States)

    Wolfe, George

    Papier-mache, plaster, and foam are inexpensive and versatile media for 3-dimensional classroom and studio art experiences. They can be used equally well by elementary, high school, or college students. Each medium has its own characteristic. Papier-mache is pliable but dries into a hard, firm surface that can be waterproofed. Plaster can be…

  1. The performance of a restoration plaster in the field: Investigation and monitoring of two case studies

    NARCIS (Netherlands)

    Lubelli, B.; Hees, R.P.J. van; Groot, C.J.W.P.

    2005-01-01

    A large number of restoration plasters, especially developed for salt loaded substrates, have been introduced on the market in the last decades. The performance of these plasters in the field is not always satisfactory. The reasons of the failures may be found in the severity of the exposure conditi

  2. 3-D Wizardry: Design in Papier-Mache, Plaster, and Foam.

    Science.gov (United States)

    Wolfe, George

    Papier-mache, plaster, and foam are inexpensive and versatile media for 3-dimensional classroom and studio art experiences. They can be used equally well by elementary, high school, or college students. Each medium has its own characteristic. Papier-mache is pliable but dries into a hard, firm surface that can be waterproofed. Plaster can be…

  3. Interaction of gypsum with lead in aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Astilleros, J.M., E-mail: jmastill@geo.ucm.es [Dpto. Cristalografia y Mineralogia, Universidad Complutense de Madrid, Jose Antonio Novais, 2, E-28040 Madrid (Spain); Godelitsas, A. [Department of Mineralogy and Petrology, Faculty of Geology and Geoenvironment, University of Athens, Panepistimioupoli Zographou, 15784 Athens (Greece); Rodriguez-Blanco, J.D. [School of Earth and Environments, Faculty of Environment, University of Leeds, Leeds LS2 9JT (United Kingdom); Fernandez-Diaz, L. [Dpto. Cristalografia y Mineralogia, Universidad Complutense de Madrid, Jose Antonio Novais, 2, E-28040 Madrid (Spain); Prieto, M. [Dpto. de Geologia, Universidad de Oviedo, E-30005 Oviedo (Spain); Lagoyannis, A.; Harissopulos, S. [Tandem Accelerator Laboratory, Institute of Nuclear Physics, NCSR ' Demokritos' , GR-15310 Attiki (Greece)

    2010-07-15

    Sorption processes on mineral surfaces are a critical factor in controlling the distribution and accumulation of potentially harmful metals in the environment. This work investigates the effectiveness of gypsum (CaSO{sub 4}.2H{sub 2}O) to sequester Pb. The interaction of gypsum fragments with Pb-bearing solutions (10, 100 and 1000 mg/L) was monitored by performing macroscopic batch-type experiments conducted at room temperature. The aqueous phase composition was periodically determined by Atomic Absorption Spectrometry (AAS), Ion Chromatography (IC) and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Regardless of the [Pb{sub aq}]{sub initial}, a [Pb{sub aq}]{sub final} < 4 mg/L was always reached. The uptake process was fast (t < 1 h) for [Pb{sub aq}]{sub initial} {>=} 100 mg/L and significantly slower (t > 1 week) for [Pb{sub aq}]{sub initial} = 10 mg/L. Speciation calculations revealed that after a long time of interaction (1 month), all the solutions reached equilibrium with respect to both gypsum and anglesite. For [Pb{sub aq}]{sub initial} {>=} 100 mg/L, sorption takes place mainly via the rapid dissolution of gypsum and the simultaneous formation of anglesite both on the gypsum surface and in the bulk solution. In the case of [Pb{sub aq}]{sub initial} = 10 mg/L, no anglesite precipitation was observed, but surface spectroscopy (proton Rutherford Backscattering Spectroscopy, p-RBS) confirmed the formation of Pb-bearing surface layers on the (0 1 0) gypsum surface in this case also. This study shows that the surface of gypsum can play an important role in the attenuation of Pb in contaminated waters.

  4. Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

    Energy Technology Data Exchange (ETDEWEB)

    Jessica Marshall Sanderson

    2006-06-01

    This report presents and discusses results from Task 5 of the study ''Fate of Mercury in Synthetic Gypsum Used for Wallboard Production,'' performed at a full-scale commercial wallboard plant. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. The FGD process is used to control the sulfur dioxide emissions which would result in acid rain if not controlled. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies developed for power plants involve the capture of mercury in FGD systems. The objective of this study is to determine whether any mercury is released into the atmosphere when the synthetic gypsum material is used as a feedstock for wallboard production. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope includes five discrete tasks, each conducted at various USG wallboard plants using synthetic gypsum from different FGD systems. The five tasks were to include (1) a baseline test, then variations representing differing power plant (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5, which was to evaluate gypsum produced from an alternate FGD reagent, could not be conducted as planned. Instead, Task 5 was conducted at conditions similar to a previous task, Task 3, although with gypsum from an alternate FGD system. In this project, process stacks in the wallboard plant have been sampled using the Ontario

  5. Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

    Energy Technology Data Exchange (ETDEWEB)

    Jessica Sanderson

    2007-12-31

    This report presents and discusses results from the project 'Fate of Mercury in Synthetic Gypsum Used for Wallboard Production', performed at five different full-scale commercial wallboard plants. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies involve the capture of mercury in FGD systems. The objective of this study has been to determine whether any mercury is released into the atmosphere at wallboard manufacturing plants when the synthetic gypsum material is used as a feedstock for wallboard production. The project has been co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope included seven discrete tasks, each including a test conducted at various USG wallboard plants using synthetic gypsum from different wet FGD systems. The project was originally composed of five tasks, which were to include (1) a base-case test, then variations representing differing power plant: (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5,could not be conducted as planned and instead was conducted at conditions similar to Task 3. Subsequently an opportunity arose to test gypsum produced from the Task 5 FGD system, but with an additive expected to impact the stability of mercury, so Task 6 was added to the project. Finally, Task 7 was added to evaluate synthetic gypsum produced at a power plant from an

  6. Theoretical determination of O and S isotope fractionations between gypsum and aqueous sulfate

    Science.gov (United States)

    Liu, Y.; Bao, H.

    2009-12-01

    Some non-labile oxyanions, such as sulfate (SO42-) or nitrate (NO3-), do not exchange O atoms readily with O in water at ambient temperatures. They often behave like a single atom during mineral precipitation, dissolution, adsorption, and even microbial transport. Considering the many different isotopologues these oxyanions usually possess, for example, SO42- has 32-16-16-16-16, 34-16-16-16-16, 32-18-16-16-16, 34-18-16-16-16, …, etc., the behaviour of isotope fractionation for different elements in the oxyanions (e.g., O and S) may lead to certain degrees of coupling during different physical, chemical, and biological processes. Here, we use an aqueous sulfate - solid gypsum (CaSO4-2H2O) system to illustrate a first-principle approach to calculating the isotope fractionation factors and their coupling for O and S in sulfate during gypsum precipitation. Using Urey model or Bigeleisen-Mayer equation in combination with quantum chemistry calculations (at B3LYP/6-311+G(2df,p) level), we have calculated equilibrium isotope fractionation factors α18 and α34 for tens of isotopologues of SO42-. We use a time-consuming yet explicit solvent model (i.e. “water-droplet”) to precisely evaluate solvation effects for aqueous sulfate species. A large and partially fixed cluster model is used for simulating gypsum mineral surface. Our results show that the equilibrium fractionations at 25°C between solid gypsum and aqueous sulfate are ~ 2.5 and 1.6 ‰ for the Δδ18O and Δδ34S, respectively. Without considering ion-pair effect on sulfate anion in solution, however, the corresponding Δδ18O and Δδ34S become ~ 4.4 and 2.8 ‰, respectively. Our work presents a new approach to predicting isotope fractionation behaviour for no-labile species at equilibrium and lays the ground for evaluating kinetic effects. The results also shed lights on the mechanism and model for gypsum crystal growth at molecular level.

  7. Synthesis on research results of FGD gypsum briquetting

    Directory of Open Access Journals (Sweden)

    Kosturkiewicz Bogdan

    2017-01-01

    Full Text Available FGD gypsum products can be characterized by significant solubility in water and dusting in dry state. These characteristics can cause a considerable pollution of air, water and soil. Among many approaches of preparing utilization of this waste, the process of compaction using briquetting has proved to be very effective. Using FGD gypsum products a new material of fertilizers characteristics has been acquired and this material is resistant to the conditions of transportation. This paper presents results of experimental briquetting of flue gas desulphurisation products in a roll press. The experiments were conducted in a laboratory roll presses LPW 450 and LPW 1100 equipped with two interchangeable forming rings that form material into saddle-shaped briquettes with volume 6,5 cm3 and 85 cm3. The experiments were conducted with various percentage amounts of FGD gypsum moisture. The results provided information regarding influence of moisture and roll press configuration on quality of briquettes. On the basis of obtained results, technological process and a general outline of technological line for FGD gypsum were developed. Two roll presses of own construction with different outputs were identified as appropriate for this purpose. A range of necessary works related to their adaptation for the FGD gypsum briquetting were pointed out.

  8. Converting SDAP into gypsum in a wet limestone scrubber

    Energy Technology Data Exchange (ETDEWEB)

    Fogh, F. [Faelleskemikerne, Elsamprojekt A/S, Fredericia (Denmark)

    1996-12-01

    The ELSAM power pool has an installed electrical capacity of approx. 5 GW{sub e}, mainly firing import coal. The major base load units are equipped with desulphurization units and three different desulphurization technologies are used: the wet limestone gypsum process, the spray dry absorption process and a sulphuric acid process. Gypsum and sulphuric acid are commercialized, whereas it has been difficult to utilize the spray dry absorption product (SDAP). The main constituents of SDAP are calcium sulphide, calcium chloride, hydrated lime and impurities mainly originating from fly ash. Sulphide can be oxidized into sulphate in acidic solution - the reaction is utilized in the wet limestone gypsum process - and the possibility of using any spare capacity in the wet limestone gypsum units to oxidize the sulphide content of SDAP into sulphate and produce usable gypsum has been investigated in the laboratory and in a 400 MW{sub e} equivalent wet limestone unit. The limestone inhibition effect of the addition of SDAP is currently being studied in the laboratory in order to determine the effect of different SDAP types (plant/coal sources) on limestone reactivity before further long-term full-scale tests are performed and permanent use of the process planned. (EG)

  9. Using stable isotopes (δ^{18}O and δ$D) of gypsum hydration water to unravel the mode of gypsum speleothem formation in semi-arid caves

    Science.gov (United States)

    Gázquez, Fernando; Calaforra, Jose Maria; Evans, Nicholas P.; Hodell, David A.

    2016-04-01

    Subaerial gypsum speleothems form during the evaporation of calcium-sulfate-rich solutions in caves. The evaporation of infiltration water is the widely accepted mechanism to explain precipitation of gypsum speleothems; i.e., the dissolution of gypsum host-rock (e.g. Messinian marine gypsum) supplies Ca2+ and SO42- ions to cave waters and subsequent evaporation leads to gypsum saturation. However, water condensation actively occurs in caves of semi-arid regions and plays a key role in subaerial cave speleogenesis and recharge of aquifers in low-rainfall environments. To date, water condensation in karstic environments has not been considered as an important factor in gypsum speleothem formation. We collected speleothem samples from the upper passages of Covadura Cave in the gypsum karst of Sorbas (Almeria, SE Spain). This cave is located in a temperate (annual mean temperature of 19.5oC), semi-arid region (

  10. Mineral potential of clays that cover the gypsum deposits in Araripina-PE region; Potencial mineral das argilas que recobrem as jazidas de gipsita na regiao de Araripina-PE

    Energy Technology Data Exchange (ETDEWEB)

    Lira, B.B.; Anjos, I.F. dos, E-mail: belarminolira@ct.ufpb.br [Universidade Federal da Paraiba (CT/UFPB), PB (Brazil); Rego, S.A.B.C. [Universidade Federal de Pernambuco (PGEM/DEMEC/UFPE), PE (Brazil)

    2011-07-01

    In the present work the applicability of the clays that cover the deposits of Gypsum Plaster in the region of Araripina - PE for use as the ceramic pigments and for bricks production in the red ceramic industry was analyzed. The clay minerals contained the illite, kaolinite and smectite, with high proportion of the last one. The possibility of industrial application of this mineral clay is considerable; however, the mining industries that mine and process the gypsum in the region do not take the clays into account as the potential mineral. In general, industries use the clay minerals in manufacturing processes or as key raw materials, or as the alternatives for some kinds of the chemical processing industries. This paper aims to highlight the potential of materials that cover the deposits of gypsum in reference. The material sampled from different deposit layers was characterized and the physical treatment of ore was applied. The results showed that the material analyzed can be used in various kinds of industry, such as the production of natural ceramic pigments. (author)

  11. Theoretical preconditions for optimization of composition and technological parameters of the plaster for walls made of aerated concrete blocks (rus

    Directory of Open Access Journals (Sweden)

    Paruta V.A.

    2012-12-01

    Full Text Available The paper reveals the mechanism of cracking in the "aerated concrete masonry - plaster coating" system, which causes the reduction of cladding’s durability. The temperature deformations in the structure are analyzed. On this basis the theoretical background to optimize the composition and technological parameters of the plaster was developed. The composition of plaster mixtures based on the expanded clay, carbonate, perlite and other fillers was also developed. The proposition that targeted modification of plaster can ensure optimal operation of the "laying-plaster" system is experimentally confirmed.

  12. Calcium isotopic fractionation in microbially mediated gypsum precipitates

    Science.gov (United States)

    Harouaka, Khadouja; Mansor, Muammar; Macalady, Jennifer L.; Fantle, Matthew S.

    2016-07-01

    Gypsum (CaSO4·2H2O) precipitation experiments were carried out at low pH in the presence of the sulfur oxidizing bacterium Acidithiobacillus thiooxidans. The observed Ca isotopic fractionation (expressed as Δ44/40Cas-f = δ44/40Casolid-δ44/40Cafluid) at the end of each experimental time period (∼50 to 60 days) was -1.41‰ to -1.09‰ in the biotic experiments, -1.09‰ in the killed control, and -1.01‰ to -0.88‰ in the abiotic controls. As there were no strong differences in the solution chemistry and the rate at which gypsum precipitated in the biotic and abiotic controls, we deduce a biological Ca isotope effect on the order of -0.3‰. The isotope effect correlates with a difference in crystal aspect ratios between the biotic experiments (8.05 ± 3.99) and abiotic controls (31.9 ± 8.40). We hypothesize that soluble and/or insoluble organic compounds selectively inhibit crystal growth at specific crystal faces, and that the growth inhibition affects the fractionation factor associated with gypsum precipitation. The experimental results help explain Ca isotopic variability in gypsum sampled from a sulfidic cave system, in which gypsum crystals exhibiting a diversity of morphologies (microcrystalline to cm-scale needles) have a broad range of δ44/40Ca values (∼1.2-0.4‰) relative to the limestone wall (δ44/40Ca = 1.3‰). In light of the laboratory experiments, the variation in Ca isotope values in the caves can be interpreted as a consequence of gypsum precipitation in the presence of microbial organic matter and subsequent isotopic re-equilibration with the Ca source.

  13. Triple oxygen isotope systematics of structurally bonded water in gypsum

    Science.gov (United States)

    Herwartz, Daniel; Surma, Jakub; Voigt, Claudia; Assonov, Sergey; Staubwasser, Michael

    2017-07-01

    The triple oxygen isotopic composition of gypsum mother water (gmw) is recorded in structurally bonded water in gypsum (gsbw). Respective fractionation factors have been determined experimentally for 18O/16O and 17O/16O. By taking previous experiments into account we suggest using 18αgsbw-gmw = 1.0037; 17αgsbw-gmw = 1.00195 and θgsbw-gmw = 0.5285 as fractionation factors in triple oxygen isotope space. Recent gypsum was sampled from a series of 10 ponds located in the Salar de Llamara in the Atacama Desert, Chile. Total dissolved solids (TDS) in these ponds show a gradual increase from 23 g/l to 182 g/l that is accompanied by an increase in pond water 18O/16O. Gsbw falls on a parallel curve to the ambient water from the saline ponds. The offset is mainly due to the equilibrium fractionation between gsbw and gmw. However, gsbw represents a time integrated signal biased towards times of strong evaporation, hence the estimated gmw comprises elevated 18O/16O compositions when compared to pond water samples taken on site. Gypsum precipitation is associated with algae mats in the ponds with lower salinity. No evidence for respective vital effects on the triple oxygen isotopic composition of gypsum hydration water is observed, nor are such effects expected. In principle, the array of δ18Ogsbw vs. 17Oexcess can be used to: (1) provide information on the degree of evaporation during gypsum formation; (2) estimate pristine meteoric water compositions; and (3) estimate local relative humidity which is the controlling parameter of the slope of the array for simple hydrological situations. In our case study, local mining activities may have decreased deep groundwater recharge, causing a recent change of the local hydrology.

  14. Characteristics, resource utilization and safety profile of patients prescribed with neuropathic pain treatments: a real-world evidence study on general practices in Europe - the role of the lidocaine 5% medicated plaster.

    Science.gov (United States)

    Katz, Pablo; Pegoraro, Valeria; Liedgens, Hiltrud

    2017-08-01

    To identify characteristics, resource utilization, and safety profile of patients prescribed with lidocaine 5% medicated plaster, pregabalin, gabapentin, amitriptyline and duloxetine when experiencing pain in the real-world setting of general practitioners (GPs) in Europe. Retrospective analysis on real world data from IMS Health Longitudinal Patient Database. Patients with at least one prescription of the drugs of interest during 2014 were selected and those with a non-neuropathic pain-related diagnosis were excluded. Patients' demographic and clinical characteristics, resource utilization data and adverse drug reactions (ADRs) as described in the leaflet were extracted. The association between treatments and ADR occurrence was evaluated applying multivariate logistic models. A total of 70,515 patients were selected from Italy, Germany, the UK, Spain and Belgium. Lidocaine 5% medicated plaster patients were the oldest in Italy, the UK and Spain and the most health impaired in Italy, Spain and Belgium. No relevant differences in the number of co-prescriptions, specialist visits, examinations and hospitalizations were found. Significantly less lidocaine 5% plasters patients experienced ADRs, with odds ratios in favor of lidocaine 5% medicated plasters ranging from 3.41 (p = .036) to 52.33 (p plaster patients showing a better safety profile, but also a comparable level of resource utilization. A possible re-evaluation of the scientific value coming from this retrospective study in building up a diagnostic as well as a therapeutic algorithm is suggested.

  15. The topical 5% lidocaine medicated plaster in localized neuropathic pain: a reappraisal of the clinical evidence.

    Science.gov (United States)

    de León-Casasola, Oscar A; Mayoral, Victor

    2016-01-01

    Topical 5% lidocaine medicated plasters represent a well-established first-line option for the treatment of peripheral localized neuropathic pain (LNP). This review provides an updated overview of the clinical evidence (randomized, controlled, and open-label clinical studies, real-life daily clinical practice, and case series). The 5% lidocaine medicated plaster effectively provides pain relief in postherpetic neuralgia, and data from a large open-label controlled study indicate that the 5% lidocaine medicated plaster is as effective as systemic pregabalin in postherpetic neuralgia and painful diabetic polyneuropathy but with an improved tolerability profile. Additionally, improved analgesia and fewer side effects were experienced by patients treated synchronously with the 5% lidocaine medicated plaster, further demonstrating the value of multimodal analgesia in LNP. The 5% lidocaine medicated plaster provides continued benefit after long-term (≤7 years) use and is also effective in various other LNP conditions. Minor application-site reactions are the most common adverse events associated with the 5% lidocaine medicated plaster; there is minimal risk of systemic adverse events and drug-drug interactions. Although further well-controlled studies are warranted, the 5% lidocaine medicated plaster is efficacious and safe in LNP and may have particular clinical benefit in elderly and/or medically compromised patients because of the low incidence of adverse events.

  16. Venous thromboembolism during hip plaster cast immobilisation: review of the literature.

    Science.gov (United States)

    Struijk-Mulder, M C; Ettema, H B; Heyne, R A J; Rondhuis, J J; Büller, H R; Verheyen, C C P M

    2014-01-01

    There is a paucity of data regarding the risk of deep vein thrombosis during hip plaster cast immobilisation. The purpose of this article was to review the available evidence regarding the incidence of symptomatic venous thromboembolism (VTE) during hip plaster cast immobilisation. All papers describing hip plaster cast immobilisation published in the English literature retrieved from PubMed, EMBASE and the Cochrane database were reviewed. Articles regarding children, hip dysplasia, congenital hip dislocation and Legg-Calvé-Perthes were excluded. A total of three papers were available for analysis. We also describe a case of pulmonary embolism during hip cast immobilisation. The overall incidence of symptomatic VTE during hip plaster cast immobilisation was 0% in 343 patients. The incidence of symptomatic VTE in hip cast brace was 2.3% (range 0-3%). Our systematic review of the literature showed a paucity of data regarding the incidence of VTE during hip plaster cast immobilisation. We describe the first case of pulmonary embolism during hip plaster cast immobilisation. We recommend that patients who are fitted with a hip plaster cast should be routinely screened for additional risk factors. When risk factors are present, patients should be considered for pharmacological thromboprophylaxis.

  17. [Acupuncture combined with moxibustion plaster for nerve-root type cervical spondylosis].

    Science.gov (United States)

    Liu, Li-an; Zhang, Shu; Wang, Hajying; Tang Lixin

    2016-02-01

    To compare the clinical efficacy differences between acupuncture combined with moxi-bustion plaster and electroacupuncture (EA) for nerve-root type cervical spondylosis. A total of 60 casesof nerve-root type cervical spondylosis were randomly divided into a plaster group and an EA group, 30 cases ineach one. Patients in the plaster group were treated with regular acupuncture at Jiaji(EX-B 2) points and ashipoints, combined with moxibustion plaster at Gaohuang (BL 43); patients in the EA group were treated with EAat identical acupoints as plaster group. The treatment was given once a day, and 5 days were taken as one course;there was an interval of 2 days between courses and totally 2 courses were performed. The pain questionnaires andquantitative score of signs and symptoms were observed before and after treatment in the two groups. The clinicalefficacy of the two groups was compared. The total effective rate was 96. 7% (29/30) in the plastergroup, which was not significantly different from 93. 3% (28/30) in the EA group (P>0. 05). After treatment,PRI, VAS and PPI were all reduced in the two groups (all Pplaster groups (all Pplaster group (all Pplaster and EA both have superior clinical efficacy for nerve-root type cervical spondylosis; EA issuperior to acupuncture combined with moxibustion plaster on relieving pain, while acupuncture combined withmoxibustion plaster is superior to EA on improving life quality, muscle strength and feeling.

  18. Fate of Mercury in Synthetic Gypsum Used for Wallboard Production

    Energy Technology Data Exchange (ETDEWEB)

    Jessica Sanderson; Gary M. Blythe; Mandi Richardson

    2006-12-01

    This report presents and discusses results from Task 6 of the study 'Fate of Mercury in Synthetic Gypsum Used for Wallboard Production,' performed at a full-scale commercial wallboard plant. Synthetic gypsum produced by wet flue gas desulfurization (FGD) systems on coal-fired power plants is commonly used in the manufacture of wallboard. This practice has long benefited the environment by recycling the FGD gypsum byproduct, which is becoming available in increasing quantities, decreasing the need to landfill this material, and increasing the sustainable design of the wallboard product. However, new concerns have arisen as recent mercury control strategies involve the capture of mercury in FGD systems. The objective of this study is to determine whether any mercury is released into the atmosphere when the synthetic gypsum material is used as a feedstock for wallboard production. The project is being co-funded by the U.S. DOE National Energy Technology Laboratory (Cooperative Agreement DE-FC26-04NT42080), USG Corporation, and EPRI. USG Corporation is the prime contractor, and URS Group is a subcontractor. The project scope now includes six discrete tasks, each conducted at various USG wallboard plants using synthetic gypsum from different FGD systems. The project was originally composed of five tasks, which were to include (1) a baseline test, then variations representing differing power plant: (2) emissions control configurations, (3) treatment of fine gypsum particles, (4) coal types, and (5) FGD reagent types. However, Task 5, which was to include testing with an alternate FGD reagent, could not be conducted as planned. Instead, Task 5 was conducted at conditions similar to Task 3, although with gypsum from an alternate FGD system. Subsequent to conducting Task 5 under these revised conditions, an opportunity arose to test gypsum produced at the same FGD system, but with an additive (Degussa Corporation's TMT-15) being used in the FGD system. TMT-15

  19. Influence of Conditions of Preparing the Foamed Plaster on its Degree of Foaming

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2007-07-01

    Full Text Available Foamed plaster moulds are used in precision casting process of non-ferrous alloys. Casting from those moulds are characterizedby high dimensional accuracy, very good shape pattering and small surface roughness. However, a drawback of the plaster mould is very low permeability. A substational improvement of this parametr may be achived through physical or phisico-chemical treatment of the plaster slurry or prepared mould. The most advantageous results can be obtained by foaming the slurry. The investigatious comprised evaluation of the influence of mixing parametrs (mixer type, rotation and mixing time, settings the mixer in mixing device and the content of a foaming agent on the degree of foaming of the plaster. The tests were carried out using the α-plaster Hartform-H1 and Alkanol XC as a foaming agent. The structure of a slurry produced after foaming is non-homogeous. Therefore, the investigations were completed by making appropriate of this process. Analysis of the results leads to the conclusion, that the foamed plaster Hartform_H1 reaches the top degree of foaming at the following parameters: the water/plaster ratio W/G=0.55, the content of Alkanol XC a=0.07%, stirring with a perforate disc mixer at the rotation speed nm=4000 rpm during τm=30 s. In turn the top homogeneity of the foamed plaster slurry can be achieved at the rotation speed nu=1400 rpm during τu=30 s., while other parameters are the same as in the foaming process. The obtained results can provide the basis for the elaboration of the industry procedures useful in the production of the plaster moulds for precision casting.

  20. OBSERVATION ON THE THERAPEUTIC EFFECT OF AURICULAR PLASTER FOR TREATMENT OF 135 CASES OF MOTION SICKNESS

    Institute of Scientific and Technical Information of China (English)

    RAO Zhongdong; WEN Ming; HU Yuehua

    2002-01-01

    In the present paper, the therapeutic effects of auricular plaster (otopoint-pellet pressing therapy)and Western medicine (Dramamine) were compared in the treatment of 200 cases of motion sickness who were randomly divided into auricular plaster group (n = 135) and Western medicine (control) group (n = 65). Results indicated that the markedly effective rates and total effective rates of auricular plaster group and control group were 51. 1% and 23. 1 %, 94.1% and 81.6% respectively, and the therapeutic effect of the former group was significantly superior to that of the control group (P<0.01).

  1. Influence of the input parameters on the efficiency of plaster sanding with alundum abrasive discs

    Science.gov (United States)

    Krajcarz, D.; Spadło, S.; Młynarczyk, P.

    2017-02-01

    The paper presents test results concerning the relationship between selected input parameters and the process efficiency for the sanding of plaster surfaces with alundum abrasive discs. The input parameters under study were the size of the abrasive grains, the force exerted by the plaster sample pressing against the abrasive disc and the no-load rotational speed of the abrasive disc. The experimental data illustrating the relationship between the process efficiency and the particular input parameters were used to select the optimum plaster sanding conditions.

  2. Seepage Analysis of Upper Gotvand Dam Concerning Gypsum Karstification (2D and 3D Approaches)

    DEFF Research Database (Denmark)

    Sadrekarimi, Jamshid; Kiyani, Majid; Fakhri, Behnam;

    2011-01-01

    Upper Gotvand Dam is constructed on the Karun River at the south west of Iran. In this paper, 2D and 3D models of the dam together with the foundation and abutments were established, and several seepage analyses were carried out. Then, the gypsum veins that are scattered throughout the foundation...... ground were included in the models, and the seepage pattern, considering the dissolution law of gypsum, was analyzed. It was disclosed that the discharge fluxes obtained from 2D and 3D analyses are not similar, and the discharge flux in 3D model is about four times that of the 2D model. Also, the 3D...... model locates the phreatic surface somewhat higher than the 2D model. This means that the 2D model estimates lower pore water pressure pattern in comparison with the 3D model. These may be attributed to the fact that with 2D model the lateral components of vectors of seepage velocity are ignored...

  3. Physicochemical Properties and Cellular Responses of Strontium-Doped Gypsum Biomaterials

    Directory of Open Access Journals (Sweden)

    Amir Pouria

    2012-01-01

    Full Text Available This paper describes some physical, structural, and biological properties of gypsum bioceramics doped with various amounts of strontium ions (0.19–2.23 wt% and compares these properties with those of a pure gypsum as control. Strontium-doped gypsum (gypsum:Sr was obtained by mixing calcium sulfate hemihydrate powder and solutions of strontium nitrate followed by washing the specimens with distilled water to remove residual salts. Gypsum was the only phase found in the composition of both pure and gypsum:Sr, meanwhile a shift into lower diffraction angles was observed in the X-ray diffraction patterns of doped specimens. Microstructure of all gypsum specimens consisted of many rod-like small crystals entangled to each other with more elongation and higher thickness in the case of gypsum:Sr. The Sr-doped sample exhibited higher compressive strength and lower solubility than pure gypsum. A continuous release of strontium ions was observed from the gypsum:Sr during soaking it in simulated body fluid for 14 days. Compared to pure gypsum, the osteoblasts cultured on strontium-doped samples showed better proliferation rate and higher alkaline phosphatase activity, depending on Sr concentration. These observations can predict better in vivo behavior of strontium-doped gypsum compared to pure one.

  4. Suitability of coarse-grade gypsum for sodic soil reclamation: a laboratory experiment

    NARCIS (Netherlands)

    Elshout, van den S.; Kamphorst, A.

    1990-01-01

    Costs of sodic soil reclamation can be reduced when coarse-grade gypsum is used, as the production and transport prices of this gypsum are much lower than that of agricultural-grade gypsum. In a feasibility study laboratory experiments were conducted to evaluate the leaching water requirements for f

  5. Tratamentos superficiais visando à melhoria da aderência entre gesso e taliscas de bambu Surface treatments aimed at improving the adhesion between plaster and bamboo slivers

    Directory of Open Access Journals (Sweden)

    Cibelle G Silva

    2012-02-01

    Full Text Available O gesso é um aglomerante com aplicações sobretudo na fabricação de placas de forro, elementos decorativos e em paredes divisórias. No entanto, utilizando-se de uma baixa relação água/gesso e procedimentos tais como vibração, torna-se possível obter resistências mecânicas compatíveis para outras aplicações na construção civil, como é o caso de elementos estruturais. A investigação reportada no presente trabalho teve como objetivo avaliar, experimentalmente, a possibilidade de se melhorar o compósito estudado. Foram realizados tratamentos para redução da absorção de água pelas taliscas, por meio da utilização de extrato vegetal B Carbon, resina polimérica e piche. Na tentativa de melhorar a aderência na interface gesso/bambu foram utilizados adesivo epóxi, massa plástica e piche, além de confeccionados corpos de prova de gesso reforçados com taliscas de bambu, tratadas com diferentes produtos, cuja eficiência foi avaliada em ensaios mecânicos. Observou-se que, para ocorrer uma boa aderência na interface do compósito, são necessários tratamentos complementares que reduzam os efeitos da instabilidade dimensional.The gypsum is a binder with applications primarily in the manufacture of ceiling tile, decorative elements and partition walls. However, using a low water/plaster ratio and procedures such as vibration, it is possible to obtain mechanical strength compatible to other applications in construction as in the case of structural elements. The research reported in this study aimed to evaluate experimentally the possibility of improving the compound studied. Treatments were carried out to reduce water absorption by slivers through the use of plant extract B Carbon, polymer resin, and tar. In an attempt to improve the adhesion at the interface plaster/epoxy adhesive, bamboo, plastic and tar mass were used. Test specimens were made of plaster reinforced with slivers of bamboo, treated with different products

  6. Evaluation of gypsum rates on greenhouse crop production

    Science.gov (United States)

    This study was to determine the potential of an added value distribution channel for gypsum waste by evaluating various greenhouse crops with captious pH and calcium needs. Three studies consisting of: Zonal geranium (Pelargonium x hortorum) and petunia (Petunia x hybrida); tomato (Solanum lycoper...

  7. Characterization of a lime-pozzolan plaster containing phase change material

    Energy Technology Data Exchange (ETDEWEB)

    Pavlíková, Milena; Pavlík, Zbyšek; Trník, Anton; Pokorný, Jaroslav; Černý, Robert [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)

    2015-03-10

    A PCM (Phase Change Material) modified lime-pozzolan plaster for improvement of thermal energy storage of building envelopes is studied in the paper. The investigated plaster is composed of lime hydrate, pozzolan admixture based on metakaolin and mudstone, silica sand, water and paraffin wax encapsulated in polymer capsule. The reference plaster without PCM application is studied as well. The analyzed materials are characterized by bulk density, matrix density, total open porosity, compressive strength and pore size distribution. The temperature of phase change, heat of fusion and crystallization are studied using DSC (Difference Scanning Calorimetry) analysis performed in air atmosphere. In order to get information on materials hygrothermal performance, determination of thermal and hygric properties is done in laboratory conditions. Experimental data reveal a substantial improvement of heat storage capacity of PCM-modified plaster as compared to the reference material without PCM.

  8. Topical pain management with the 5% lidocaine medicated plaster--a review.

    Science.gov (United States)

    Mick, Gérard; Correa-Illanes, Gerardo

    2012-06-01

    The topical 5% lidocaine medicated plaster is recommended as first-line treatment for localized peripheral neuropathic pain. In order to provide an overview of the efficacy and safety of the lidocaine plaster in the treatment of different neuropathic pain conditions, all efficacy and safety studies (randomized, controlled, or open-label with well described methodology), case reports, and pharmacological studies on the lidocaine plaster retrieved from a PubMed literature research (1960-March 2012) plus additional references identified from retrieved articles were included. The lidocaine plaster is efficacious in the treatment of neuropathic pain symptoms associated with previous herpes zoster infection. Results from a large open-label controlled study suggest that the lidocaine plaster could be at least as effective as systemic pregabalin in the treatment of postherpetic neuralgia and painful diabetic polyneuropathy. Open-label studies indicate efficacy in the treatment of other localized neuropathic pain conditions, such as painful idiopathic sensory polyneuropathy, complex regional pain syndrome, carpal tunnel syndrome sequelae, postsurgical and posttraumatic pain. Quality of life markedly improved in a variety of neuropathic pain conditions and long-term treatment provided sustained relief in patients with neuropathic pain who are responsive to lidocaine plaster. The lidocaine plaster is usually well tolerated. The risk of systemic adverse events and pharmacokinetic interactions with concomitant medication is minimal owing to low systemic exposure. Treatment of several, primarily neuropathic and mixed-pain conditions with the 5% lidocaine medicated plaster was found efficacious and safe. Further controlled studies, in particular where only small open-label studies or case reports are available, should be considered.

  9. Long-term treatment of neuropathic pain with a 5% lidocaine medicated plaster.

    Science.gov (United States)

    Wilhelm, Ilca Ricarda; Tzabazis, Alexander; Likar, Rudolf; Sittl, Reinhard; Griessinger, Norbert

    2010-02-01

    The 5% lidocaine medicated plaster is a topical treatment for peripheral neuropathic pain symptoms (e.g. burning, shooting and stabbing pain) and is registered for the treatment of postherpetic neuralgia. This study examined the efficacy and tolerability of long-term treatment with the 5% lidocaine medicated plaster in patients with localized neuropathic pain conditions. Twenty patients with localized neuropathic pain [postoperative neuropathic pain (n = 14); complex regional pain syndrome (n = 2); and postherpetic neuralgia (n = 4)], who had been successfully treated with 5% lidocaine medicated plaster, were followed up by telephone interview after 3 and 5 years. Questions were related to the efficacy, development of tolerance, tolerability, wear time and comfort of the plaster. At 3 years, 10 out of 20 (50%) initial responders were still using the plasters with no decline in analgesic efficacy. After 5 years, eight of the original 20 responders (40%) maintained treatment and continued to experience effective pain relief. The 12 responders who discontinued treatment did so because they no longer required analgesic therapy (n = 4); their health insurer refused to fund treatment (n = 2); they were lost to follow-up (n = 1); or had died from an illness unrelated to plaster treatment (n = 5). No patient discontinued because of inadequate analgesia or intolerable side effects. Reversible erythema occurred in two patients wearing the plaster for more than 16 h. There were no systemic side effects. The 5% lidocaine medicated plaster provides sustained pain relief over long-term treatment in patients with neuropathic pain of various causes and is well tolerated.

  10. Study and application of plasticity plaster-slurry for preventing coal spontaneous combustion

    Institute of Scientific and Technical Information of China (English)

    LIU Ai-hua(刘爱华); CAI Kang-xu(蔡康旭); GUO Da(郭达); ZHANG Fu-sheng(张复胜)

    2003-01-01

    Introduced the modulation scheme, function and mechanism of plasticity plaster-slurry preventing coal spontaneous combustion. The applications show that the plasticity plaster-slurry has good hygroscopicity and adsorptivity. To spray it on the coal wall of tunnel can shut off leakage wind fast and effectively. To press it into the coal body can absorb the heat and descend the temperature, surround the coal pieces, eliminate the possibility of the fiery district resuming combustion.

  11. The topical 5% lidocaine medicated plaster in localized neuropathic pain: a reappraisal of the clinical evidence

    Directory of Open Access Journals (Sweden)

    de León-Casasola OA

    2016-02-01

    Full Text Available Oscar A de León-Casasola,1,2 Victor Mayoral3 1Department of Anesthesiology, Division of Pain Medicine, Roswell Park Cancer Institute, 2University at Buffalo, School of Medicine and Biomedical Sciences. NY, USA; 3Anesthesiology Department, Pain Management Unit, University Hospital of Bellvitge, L'Hospitalet de Llobregat, Spain Abstract: Topical 5% lidocaine medicated plasters represent a well-established first-line option for the treatment of peripheral localized neuropathic pain (LNP. This review provides an updated overview of the clinical evidence (randomized, controlled, and open-label clinical studies, real-life daily clinical practice, and case series. The 5% lidocaine medicated plaster effectively provides pain relief in postherpetic neuralgia, and data from a large open-label controlled study indicate that the 5% lidocaine medicated plaster is as effective as systemic pregabalin in postherpetic neuralgia and painful diabetic polyneuropathy but with an improved tolerability profile. Additionally, improved analgesia and fewer side effects were experienced by patients treated synchronously with the 5% lidocaine medicated plaster, further demonstrating the value of multimodal analgesia in LNP. The 5% lidocaine medicated plaster provides continued benefit after long-term (≤7 years use and is also effective in various other LNP conditions. Minor application-site reactions are the most common adverse events associated with the 5% lidocaine medicated plaster; there is minimal risk of systemic adverse events and drug–drug interactions. Although further well-controlled studies are warranted, the 5% lidocaine medicated plaster is efficacious and safe in LNP and may have particular clinical benefit in elderly and/or medically compromised patients because of the low incidence of adverse events. Keywords: 5% lidocaine medicated plaster, clinical evidence, localized neuropathic pain, postherpetic neuralgia, review

  12. [Case-control study on close reduction and plaster slab fixation combined with plaster external traction for the treatment of pediatric Gartland type III supracondylar humerus fractures].

    Science.gov (United States)

    Kang, Yu-Xiang; Wei, Xiao-Chun; Li, Hai-Ming

    2014-07-01

    To compare the therapeutic effects between close reduction and plaster slab fixation combined with plaster external traction and operation for the treatment of pediatric closed Gartland type III supracondylar humerus fractures without neurovascular injury complications. From June 2009 to June 2012, 151 children with closed Gartland III supracondylar humerus fractures were retrospectively studied and divided into two groups, including 87 boys and 64 girls, ranging in age from 1 to 12 years old with an average of 5.3 years old. Among them, 76 children (conservative group) were treated with close reduction and plaster slab fixation combined with plaster external traction; 75 children (operation group) underwent surgical operation. The time of elbow joint function exercise, the healing time of fracture, the function recovery of elbow joint and carrying angle was recorded and analyzed. The therapeutic effects were evaluated by the Flynn criteria system. All patients were followed up from 6 to 36 months (18.3 months on average). The average time of fracture healing and elbow joint functional exercise of the conservative group was shorter than those of operation group (P 0.05). According to Flynn criteria system, in conservative group, the result was excellent in 31 cases, good in 35, fair in 7, and poor in 3; in operation group, 27 in excellent, 30 in good, 17 in fair and 1 in poor; there was no significant difference between two groups in therapeutic effects (P > 0.05). Close reduction and plaster slab fixation combined with plaster external traction in treatment of pediatric closed Gartland type III supracondylar humerus fractures without neurovascular injury complications,which has similar effect to surgical treatment, and the time of fracture healing and elbow joint function exercise are significantly shorter.

  13. Antiemetic efficacy of capsicum plaster on acupuncture points in patients undergoing thyroid operation.

    Science.gov (United States)

    Koo, Min Seok; Kim, Kyo Sang; Lee, Hee-Jong; Jeong, Ji Seon; Lee, Jung-Won

    2013-12-01

    Postoperative nausea and vomiting (PONV) occurs in up to 63-84% of patients after thyroid surgery. This study aims to assess the effects of using a capsicum plaster to reduce PONV after thyroid surgery at either the Chinese acupuncture point (acupoint) Pericardium 6 (P6) or Korean hand acupuncture point K-D2. One-hundred eighty-four patients who underwent thyroid surgery were randomized in four groups (n = 46 each): control group = inactive tape at P6 acupoints and on both shoulders as a nonacupoint; P6 group = capsicum plaster at P6 points and inactive tape on both shoulders; K-D2 group = capsicum plaster at K-D2 acupoints and inactive tape on both shoulders; Sham group = capsicum plaster on both shoulders and inactive tape at P6 acupoints. The capsicum plaster was applied before the induction of anesthesia and removed at 8 hr after surgery. The incidence and severity of nausea and vomiting and the need for rescue antiemetics were decreased in the patients in the P6 and K-D2 groups compared to the patients in the control and sham groups (P plaster at the P6 and K-D2 acupoint was a promising antiemetic method for the patients undergoing thyroid surgery.

  14. Outcomes of pin and plaster versus locking plate in distal radius intraarticular fractures.

    Science.gov (United States)

    Bahari-Kashani, Mahmoud; Taraz-Jamshidy, Mohammad Hosein; Rahimi, Hassan; Ashraf, Hami; Mirkazemy, Masoud; Fatehi, Amirreza; Asadian, Mariam; Rezazade, Jafar

    2013-01-01

    Distal radius fractures are among the most prevalent fractures predictive of probable occurrence of other osteoporotic fractures. They are treated via a variety of methods, but the best treatment has not been defined yet. This study was performed to compare the results of open reduction and internal fixation with locking plates versus the pin and plaster method. In this prospective study, 114 patients aged 40 to 60 years with Fernandez type III fracture referring to Imam-Reza and Mehr hospitals of Mashhad from 2009 to 2011, were selected randomly; after obtaining informed consent, they were treated with pin and plaster fixation (n = 57) or internal fixation with the volar locking plate (n = 57). They were compared at the one year follow up. Demographic features and standard radiographic indices were recorded and MAYO, DASH and SF - 36 tests were performed. Data was analyzed by SPSS software version 13, with descriptive indices, Mann-Whitney and Chi-square tests. SF-36 test demonstrated a better general health (P plaster group. Also, in the LCP group mean MAYO score (P plaster group. Mean DASH score was not different between the groups (P = 0.218). The rate of acceptable results of radiographic indices (P plaster method. In treatment of intra-articular distal radius fractures in middle-aged patients internal fixation with locking plates may be prefered to pin and plaster as the treatment of choice.

  15. 3种消毒方法对石膏模型表面硬度的影响%Influence of three kinds of disinfection methods on surface hardness of gypsum casts

    Institute of Scientific and Technical Information of China (English)

    曹明国; 吴世莲; 陆林侦; 查光玉

    2012-01-01

    目的 研究3种消毒方法对口腔石膏模型表面硬度的影响.方法 制作圆柱体金属模具,硅橡胶取模,分别灌注熟石膏、硬石膏和超硬石膏模型,分别用3种消毒方法对其消毒,包括微波加热、高温高压及紫外线照射,消毒后测定其表面硬度,并进行统计分析.结果 微波加热及紫外线照射对3种石膏模型消毒后,表面硬度差异无统计学意义;高温高压消毒处理后的熟石膏组、硬石膏组、超硬石膏组的表面硬度分别为(3.70±0.25)、(4.46±0.30)、(4.93±0.85)Pa,均比对照组明显降低(P<0.01).结论 微波加热及紫外线照射对石膏模型消毒后,在表面硬度方面对模型无明显影响.%OBJECTIVE To study the influence of three kinds of disinfection methods on surface hardness of oral gypsum casts. METHODS The metal cylinder mould and silicone impression was made. Three kinds of gypsum casts including plaster, dental stone, and high strength dental stone were made and disinfected by three kinds of disinfection methods, which were microwave heating, high temperature and pressure and ultraviolet radiation disinfection. After disinfection, the surface hardness was tested and the statistical analysis was performed. RESULTS Disinfection with microwave heating and ultraviolet radiation did not affect the surface hardness of three kinds of gypsum casts, the difference in surface hardness was not statistically significant; the hardness of three kinds of plaster, dental stone, and high strength dental stone after the disinfection with high temperature and pressure were (3. 70 ± 0. 25, 4. 46 ± 0. 30, and 4. 93 ± 0. 85)Pa, with a significant decreases as compared with the control group (P < 0. 01). CONCLUSION Disinfection by microwave heating and ultraviolet radiation has no significant influence on the surface hardness of the gypsum casts.

  16. The Gypsum: White gold of Rajasthan, introduction, uses and future prospective

    Science.gov (United States)

    Sharma, Gayatri

    2013-06-01

    Rajasthan is mineral based state and Bikaner and its surrounding district have been gifted with Gypsum. Mt of Gypsum is available in these districts. Gypsum has multiple uses including basic raw material for POP industry, addition in cement and a natural fertilizer. This mineral has changes the economic scenario in the remote areas of Bikaner, Nagaur, Hanumangarh, Sanchore, Shriganganagar etc. Gypsum and selenite are mined about 3.0 million tons per year. There is huge demand from cement industry as Gypsum is added for improving setting time of cement. Gypsum is a natural fertilizer for alkaline land and it role is vital in state like India where alkaline land is major role. Its high use as fertilizer has potential to change millions of poor farmer families and improving in crop production. Cement Industry has started importing Gypsum from Thailand, Bankong, Pakistan, Iran etc. The mining of gypsum of purity of 70% CaSO4.2H2O is cooperative effort between the land owners and Rajasthan State Mines and Minerals Limited. Gypsum fulfills the demand of POP and Cement industry in Rajasthan and powder gypsum used in agriculture for recon dining of alkaline soil. This paper deals with multiple uses, availability, and future prospective of Gypsum, a white gold of Rajasthan.

  17. EXPERIENCE OF USING THE MONTE-CARLO METHOD IN DETERMINING OPTIMAL PLASTER COMPOSITIONS WITH IMPROVED STRENGTH PROPERTIES

    Directory of Open Access Journals (Sweden)

    Khrystyna Moskalova

    2017-01-01

    Full Text Available Considering that modern building materials impose increasing performance requirements, it is necessary to expand the range of building materials and improve their multicomponent composition. The effects of polymer and porous components (expanded perlite sand and carbonate filler – limestone-shell rock in cement-lime light plaster on the physico-mechanical properties of the mixtures under equal workability conditions of mixtures are analyzed based on experimental-statistical modeling. The results of the physico-mechanical and operational experiments confirm the rationality of using porous fillers and additives to improve certain specific properties of the final product. The so-called Monte-Carlo method is implemented for determining an optimal composition of multicomponent cement-lime light plaster, based on multivariate statistical modeling and iterative random scanning of property fields. According to the results of the computational experiment, a composition that reduces the number of expensive mixture components and improves the physical and mechanical characteristics of the resulting composition is selected.

  18. Simulation and Prediction of Ion Transport in the Reclamation of Sodic Soils with Gypsum Based on the Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Jinman Wang

    2014-01-01

    Full Text Available The effect of gypsum on the physical and chemical characteristics of sodic soils is nonlinear and controlled by multiple factors. The support vector machine (SVM is able to solve practical problems such as small samples, nonlinearity, high dimensions, and local minima points. This paper reports the use of the SVM regression method to predict changes in the chemical properties of sodic soils under different gypsum application rates in a soil column experiment and to evaluate the effect of gypsum reclamation on sodic soils. The research results show that (1 the SVM soil solute transport model using the Matlab toolbox represents the change in Ca2+ and Na+ in the soil solution and leachate well, with a high prediction accuracy. (2 Using the SVM model to predict the spatial and temporal variations in the soil solute content is feasible and does not require a specific mathematical model. The SVM model can take full advantage of the distribution characteristics of the training sample. (3 The workload of the soil solute transport prediction model based on the SVM is greatly reduced by not having to determine the hydrodynamic dispersion coefficient and retardation coefficient, and the model is thus highly practical.

  19. [Treatment of ulcerative colitis with spleen and kidney yang deficiency by kuijiening plaster: a randomized controlled study].

    Science.gov (United States)

    Huang, Lei; Cai, Zhi; Zhu, Ying; Wan, Hu

    2013-07-01

    To explore the clinical efficacy of ulcerative colitis with spleen and kidney yang deficiency by kuijiening plaster and the impacts on IFN-gamma and IL-4 contents, as well as make the comparison with oral medication of sulfasalzine (SASP). Sixty patients of ulcerative colitis with spleen and kidney yang deficiency were randomized into a Kuijiening plaster group, a SASP group and a combined therapy group, 20 cases in each one. In the Kuijiening plaster group, Kuijiening plaster and oral administration of placebo SASP were applied. The plaster was used at Shangjuxu (ST 37), Tianshu (ST 25), Zusanli (ST 36), Mingmen (GV 4) and Guanyuan (CV 4). In the SASP group, was applied Kuijiening plaster placebo at the points and SASP oral administration was adopted. In the combined therapy group, Kuijiening plaster and SASP oral administration were given. The duration of treatment was 60 days. The follow-up visit was 2 months after treatment. The comprehensive efficacy, the efficacy on TCM syndrome and the changes in serum IFN-gamma and IL-4 before and after treatment were compared among the three groups. The efficacy on TCM syndrome in the Kuijiening plaster was similar to the SASP group [85.0% (17/20) vs 75.0% (15/20), P > 0.05]. The efficacy on TCM syndrome in the Kuijiening plaster group was superior to the western medicine group [80.0% (16/20) vs 60.0% (12/20), P plaster group were superior to the SASP group (P plaster is effective in the treatment of ulcerative colitis of spleen and kidney yang deficiency, which is not inferior to that of SASP. The efficacy of kuijiening plaster on relieving TCM syndrome and improving body immunity is much superior to SASP. The effect is much better with SASP combined in the treatment.

  20. Preparation of Plaster Moulage (Cast in Plastic Surgery patients

    Directory of Open Access Journals (Sweden)

    Rana R

    2003-01-01

    Full Text Available The purpose of this paper is to describe the technique of making casts using alginate compound for negative and dental stone plaster for positive impressions. With certain modifications a cast could be made of any part of the body and one can make a museum of interesting cases. Casts serve as useful teaching material especially in cleft lip and palate patients to study the effect of surgery on growth and development of the cleft lip-palate-nose complex in relation to the remaining face. It also helps in planning reconstruction in cases of facial defects, recording serial changes in multistage surgery, pre-operative and post-operative comparison as in rhinoplasty, ear reconstruction, hand etc; for comparing results before and after treatment in keloid and hypertrophic scars, fabrication of implants and preparation of prosthesis. In spite of newer modalities like 3-D imaging and stereolithography, the usefulness of this old technique in certain interesting cases can not be denied.

  1. Wet or dry bandages for plaster back-slabs?

    Science.gov (United States)

    Baliga, Santosh; Finlayson, D

    2012-12-01

    Cotton crêpe and stretch bandages are commonly used in back-slabs and casts in orthopaedic practice. In theory they allow swelling to occur after injury while splinting the fracture. The application of a wet bandage prevents the Plaster-of-Paris (POP) setting too rapidly, giving time to apply a mould or attain correct limb position. However, we hypothesised that a wet bandage contracts upon drying and may cause constriction of the splint. This study aimed at determining whether there was any significant change in length of commonly used bandages when wet as well as any further change when left to dry again. Two types of bandage were evaluated. 250 mm strips of bandage were dipped into water, gently squeezed and laid flat on a bench. The bandage was then immediately measured in length. The strips were then left to dry and re-measured. This experimental study shows that both cotton crepe and cling significantly shrink by around 7% when wet. This phenomenon has the potential to significantly increase the pressure exerted on the limb by a back-slab. We speculate that the application of wet bandages is why some back-slabs may need released. It is therefore recommended that bandages should be applied only in the dry form. Copyright © 2011 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier Ltd. All rights reserved.

  2. Sulphate behaviour from dissolution of gypsum in organic acids

    Energy Technology Data Exchange (ETDEWEB)

    Baruah, M.K.; Gogoi, P.C.; Kotoky, P. [NNS College, Titabar (India). Dept. of Chemistry

    2000-01-01

    The solubility of gypsum in organic acids namely acetic, oxalic, tartaric and succinic acids at low temperature (30{degree}C) was studied. The results show that sulphate sulphur content increases with increasing acid concentration from 0.1 to 0.25 M and decreases again at higher concentration. It is suggested that different behaviour of the acids beyond 0.25 M solution could be due to incorporation of sulphate into the co-ordination sphere of calcium-organic complexes. It is suggested that the occurrence of free and fixed sulphate in the solution is highly pH dependent. The nature of incorporation of sulphate in a system containing calcium species and natural organic matter has also been studied. Humic acids, extracted from forest and tea-garden soils, were treated with a solution of gypsum (CaSO{sub 4}.2H{sub 2}O) at room temperature and the infrared spectra of the gypsum treated samples reveal that sulphate has been incorporated into the calcium complex as a monodentate ligand. Further an inorganic-sulphur free high-sulphur coal when treated with the gypsum solution, incorporated sulphate as bidentate ligand. It is concluded that the nature of the organic matter plays an important role for the occurrence of various fixed sulphates either as monodentate or bidentate ligand in natural systems. This work is a novel breakthrough for the occurrence of varying sulphate content in some of the natural environments and has considerable environmental and geochemical interest. Short communication. 46 refs., 3 figs.

  3. Comparison of Energy Dissipation, Stiffness, and Damage of Structural Oriented Strand Board (OSB, Conventional Gypsum, and Viscoelastic Gypsum Shearwalls Subjected to Cyclic Loads

    Directory of Open Access Journals (Sweden)

    Andrew S. Blasetti

    2012-06-01

    Full Text Available A key element in the seismic load resisting system of a wood framed structure is the shear wall which is typically sheathed on one side with plywood or oriented strand board (OSB and gypsum on the other. The shear capacity of gypsum sheathed shear walls is typically neglected in high seismic areas due to the susceptibility of conventional drywall screw connections to damage caused by earthquakes. The earthquake resistance of an innovative viscoelastic (VE gypsum shearwall is evaluated and compared to conventional structural and non-structural walls. Ten 8 ft × 8 ft wood framed wall specimens of three configurations [nailed-OSB, screw-gypsum, and VE polymer-gypsum] were subjected to a cyclic test protocol. The energy dissipation, stiffness, and damage characteristics of all shearwalls are reported herein. Testing results indicate the VE-gypsum walls can dissipate more energy than the OSB structural panels and 500% more energy that the conventional gypsum sheathed walls and contains a constant source of energy dissipation not seen in the structural and non-structural walls. The wall stiffness of the OSB wall degrades at a far greater rate that the VE gypsum wall and at continued cycling degrades below the VE wall stiffness. Unlike both of the conventional wall types, the VE wall showed no visible or audible signs of damage when subjected to shear displacements up to 1.

  4. Manufacturing of calcium phosphate scaffolds by pseudomorphic transformation of gypsum

    Energy Technology Data Exchange (ETDEWEB)

    Araujo Batista, H. de.; Batista Cardoso, M.; Sales Vasconcelos, A.; Vinicius Lia Fook, M.; Rodriguez Barbero, M. A.; Garcia Carrodeguas, R.

    2016-08-01

    Carbonated hydroxyapatite (CHAp) and β-tricalcium phosphate (β-TCP) have been employed for decades as constituents of scaffolds for bone regeneration because they chemically resemble bone mineral. In this study, the feasibility to manufacture CHAp/β-TCP scaffolds by pseudomorphic transformation of casted blocks of gypsum was investigated. The transformation was carried out by immersing the precursor gypsum block in 1 M (NH{sub 4}){sub 2}HPO{sub 4}/1.33 M NH{sub 4}OH solution with liquid/solid ratio of 10 mL/g and autoclaving at 120 degree centigrade and 203 kPa (2 atm) for 3 h at least. Neither shape nor dimensions significantly changed during transformation. The composition of scaffolds treated for 3 h was 70 wt.% CHAp and 30 wt.% β-TCP, and their compressive and diametral compressive strengths were 6.5 ± 0.7 and 5.3 ±0.7 MPa, respectively. By increasing the time of treatment to 6 h, the composition of the scaffold enriched in β-TCP (60 wt.% CHAp and 40 wt.% β-TCP) but its compressive and diametral compressive strengths were not significantly affected (6.7 ± 0.9 and 5.4 ± 0.6 MPa, respectively). On the basis of the results obtained, it was concluded that this route is a good approach to the manufacturing of biphasic (CHAp/β-TCP) scaffolds from previously shaped pieces of gypsum. (Author)

  5. Constraints from sulfur isotopes on the origin of gypsum at concrete/claystone interfaces

    Science.gov (United States)

    Lerouge, Catherine; Claret, Francis; Tournassat, Christophe; Grangeon, Sylvain; Gaboreau, Stéphane; Boyer, Bernard; Borschnek, Daniel; Linard, Yannick

    Two in situ concrete/claystone interfaces were sampled at the laboratory level in the Andra Meuse/Haute Marne (France) Underground Research Laboratory (URL) in order to study five years of interactions between Callovian-Oxfordian (COx) claystone and two cementitious materials (concrete bottom slab and shotcrete on the walls of the main gallery), with a specific focus on sulfur. Combined mineralogical, chemical and sulfur isotopic investigations were carried out to define the degree of the perturbation of the sulfur system in the claystone and in both the cementitious materials. At both interfaces, results show that the main perturbation on the claystone side is the formation of scarce μm-sized gypsum, the sulfur content of which is essentially derived from pyrite oxidation. The distribution of gypsum is highly correlated with the fissure network of the damaged zone due to excavation of the gallery. Its presence is also often associated with a loss of cohesion of the concrete/claystone interface. Due to the small amounts of gypsum and its μm-size, measurements were performed by ion microprobe. Adaptations were needed on account of the reactivity of gypsum and sulfates in general under the beam. The use of ion microprobe analysis provided evidence of high local isotopic heterogeneity that could be attributed to kinetic fractionation effects. Some analyses suggest a minor contribution of dissolved sulfates in pore water of claystone and possibly of concrete. The perturbation on the concrete side is marked by a significant increase in the bulk sulfur content within three millimeters of the interface with the claystone, showing a sulfur gradient from claystone to concrete. The main objective of this work was to define the extent of the chemical and mineralogical perturbations, taking into account in situ URL conditions, i.e. hydrodynamic conditions (shotcrete sprayed on the gallery walls and subjected to ventilation of the galleries), damaged zone of claystone induced

  6. Differences in gypsum plant communities associated with habitat fragmentation and livestock grazing.

    Science.gov (United States)

    Pueyo, Y; Alados, C L; Barrantes, O; Komac, B; Rietkerk, M

    2008-06-01

    The negative consequences of habitat fragmentation for plant communities have been documented in many regions of the world. In some fragmented habitats, livestock grazing has been proposed to be a dispersal mechanism reducing isolation between fragments. In others, grazing acts together with fragmentation in a way that increases habitat degradation. Iberian gypsum plant communities have been grazed and fragmented by agricultural practices for centuries. Although their conservation is considered a priority by the European Community, the effects of fragmentation on gypsum plant communities and the possible role of livestock grazing remain unknown. In addition, a substantial proportion of plant species growing in gypsum environments are gypsum specialists. They could be particularly affected by fragmentation, as was found for other habitat specialists (i.e., serpentine and calcareous specialists). In this study (1) we investigated the effect of fragmentation and grazing on gypsum plant community composition (species and life-forms), and (2) we tested to see if gypsum specialists were differently affected by fragmentation and grazing than habitat generalists. A vegetation survey was conducted in the largest gypsum outcrop of Europe (Middle Ebro Valley, northeast Spain). Fragmented and continuous sites in grazed and ungrazed areas were compared. Measurements related to species and composition of life-forms were contrasted first for the whole gypsum plant community and then specifically for the gypsum specialists. In the whole community, our results showed lower plant species diversity in fragmented sites, mainly due to the larger dominance of species more tolerant to fragmented habitat conditions. With livestock grazing, the plant species richness and the similarity in plant species composition between remnants was larger, suggesting that animals were acting as dispersal agents between fragments. As expected, gypsum specialists were less abundant in fragmented areas

  7. Crystallisation of Gypsum and Prevention of Foaming in Wet Flue Gas Desulphurisation (FGD) Plants

    DEFF Research Database (Denmark)

    Hansen, Brian Brun

    of reliability of operation and consistency of the gypsum quality obtained. This work may furthermore be of interest to other industrial systems in which foaming or gypsum crystallisation may take place. FGD is an industrial process, which removes sulphur dioxide (SO2) from flue gasses generated by fossil fuel...... combustion at power plants and other heavy industries, thereby abating the detrimental effects known as “acid rain”. The majority of the 680 FGD-plants installed at power plants worldwide in 1999 (2.41•105 MWe) were using the wet FGD-technology. This process absorbs ~ 99 % of the SO2 by an alkaline slurry....... Experiments in a falling film wet FGD pilot plant have shown a strong non-linear behaviour (in a ln(n(l)) vs. l plot) at the lower end of the particle size range, compared to the well-known linear “mixed suspension mixed product removal (MSMPR)” model. A transient population balance model, fitted...

  8. A comparison of the accuracy of polyether, polyvinyl siloxane, and plaster impressions for long-span implant-supported prostheses.

    Science.gov (United States)

    Hoods-Moonsammy, Vyonne J; Owen, Peter; Howes, Dale G

    2014-01-01

    The purpose of this study was to compare the capacity of different impression materials to accurately reproduce the positions of five implant analogs on a master model by comparing the resulting cast with the stainless steel master model. The study was motivated by the knowledge that distortions can occur during impression making and the pouring of casts and that this distortion may produce inaccuracies of subsequent restorations, especially long-span castings for implant superstructures. The master model was a stainless steel model with five implant analogs. The impression materials used were impression plaster (Plastogum, Harry J Bosworth), a polyether (Impregum Penta, 3M ESPE), and two polyvinyl siloxane (PVS) materials (Aquasil Monophase and Aquasil putty with light-body wash, Dentsply). Five impressions were made with each impression material and cast in die stone under strictly controlled laboratory conditions. The positions of the implants on the master model, the impression copings, and the implant analogs in the subsequent casts were measured using a coordinate measuring machine that measures within 4 μm of accuracy. Statistical analyses indicated that distortion occurred in all of the impression materials, but inconsistently. The PVS monophase material reproduced the master model most accurately. Although there was no significant distortion between the impressions and the master model or between the impressions and their casts, there were distortions between the master model and the master casts, which highlighted the cumulative effects of the distortions. The polyether material proved to be the most reliable in terms of predictability. The impression plaster displayed cumulative distortion, and the PVS putty with light body showed the least reliability. Some of the distortions observed are of clinical significance and likely to contribute to a lack of passive fit of any superstructure. The inaccuracy of these analog materials and procedures suggested

  9. Influence of tooth dimension on the initial mobility based on plaster casts and X-ray images : A numerical study.

    Science.gov (United States)

    Hartmann, Martin; Dirk, Cornelius; Reimann, Susanne; Keilig, Ludger; Konermann, Anna; Jäger, Andreas; Bourauel, Christoph

    2017-07-01

    The goal was to determine the influence of different geometric parameters of the tooth on the initial tooth mobility and the position of the center of resistance employing numerical models based on scaled X-ray images and plaster casts. The dimensions of tooth 21 were measured in 21 patients, using radiographs and dental casts. Length and mesiodistal width of the tooth were obtained from the X-ray image and the orovestibular diameter from the plaster cast. Finite element models were generated. Cortical and cancellous bone and the periodontal ligament were simulated to create realistic models. Root length (11-17 mm), mesiodistal width (6-10 mm) and orovestibular thickness (7-9 mm) were varied in 1-mm steps to generate 105 models. In the simulation, each model was loaded with a force of 10 N in vestibulopalatinal direction and with a torque of 10 Nmm to determine tooth displacements and center of resistance. Initial tooth displacement and thus mobility increased with decreasing total root surface. The shortest, slimmest and thinnest tooth showed a total deflection of 0.14 mm at the incisal edge, while the longest, widest and thickest tooth showed a total deflection of 0.10 mm. Changes in mesiodistal width had the greatest influence on initial tooth mobility and changes in orovestibular thickness the least. The teeth's center of resistance was positioned between 37 and 43% of the root length measured from the cervical margin of the alveolar bone. The center of resistance of the longest dental root investigated was located around 6% more cervically compared to the one of the shortest dental root. The influence of root width and thickness on the position of the center of resistance was significantly lower than root length. Geometric parameters significantly impact initial tooth mobility and position of the center of resistance. Thus, tooth dimensions should be considered in orthodontic treatment planning. Dental radiographs represent a sufficient validation tool

  10. Application of Ceramic Powder as Supplementary Cementitious Material in Lime Plasters

    Directory of Open Access Journals (Sweden)

    Monika ČÁCHOVÁ

    2016-09-01

    Full Text Available In this paper, the properties of plasters based on lime – brick powder binder of varying composition (ceramics content from 0 to 80 % are studied. The plasters are prepared with a constant water amount. The pore size distribution is thus influenced in a positive way; the total porosity increases with the ceramics content but the volume of capillary pores is reduced. It results in lower water vapor diffusion resistance factor while the apparent moisture diffusivity coefficient increases just moderately. The influence of ceramic on strength of plasters is not found very important. The thermal conductivity of plasters containing ceramics is lower than those with the pure lime what is again in agreement with the pore size distribution. It can be concluded that fine brick powder can be used as pozzolanic admixture in lime based plasters with a positive influence on its functional parameters.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.7433

  11. Crystallisation of Gypsum and Prevention of Foaming in Wet Flue Gas Desulphurisation (FGD) Plants

    OpenAIRE

    Hansen, Brian Brun; Kiil, Søren; Johnsson, Jan Erik

    2008-01-01

    The aim of this project is to investigate two operational problems, which have been experienced during wet flue gas desulphurisation (FGD) operation, i.e. poor gypsum dewatering properties and foaming. The results of this work can be used for the optimization of wet FGD-plants in terms of reliability of operation and consistency of the gypsum quality obtained. This work may furthermore be of interest to other industrial systems in which foaming or gypsum crystallisation may take place. FGD is...

  12. Investigation of Parameters Affecting Gypsum Dewatering Properties in a Wet Flue Gas Desulphurization Pilot Plant

    OpenAIRE

    Hansen, Brian Brun; Kiil, Søren

    2012-01-01

    Wet flue gas desulphurization (FGD) plants with forced oxidation, installed at coal and oil fired power plants for removal of SO2(g), must produce gypsum of high quality. However, quality issues such as an excessive moisture content, due to poor gypsum dewatering properties, may occur from time to time. In this work, the particle size distribution, morphology, and filtration rate of wet FGD gypsum formed in a pilot-scale experimental setup, operated in forced oxidation mode, have been studied...

  13. Light Steel-Timber Frame with Composite and Plaster Bracing Panels

    Directory of Open Access Journals (Sweden)

    Roberto Scotta

    2015-11-01

    Full Text Available The proposed light-frame structure comprises steel columns for vertical loads and an innovative bracing system to efficiently resist seismic actions. This seismic force resisting system consists of a light timber frame braced with an Oriented Strand Board (OSB sheet and an external technoprene plaster-infilled slab. Steel brackets are used as foundation and floor connections. Experimental cyclic-loading tests were conduced to study the seismic response of two shear-wall specimens. A numerical model was calibrated on experimental results and the dynamic non-linear behavior of a case-study building was assessed. Numerical results were then used to estimate the proper behavior factor value, according to European seismic codes. Obtained results demonstrate that this innovative system is suitable for the use in seismic-prone areas thanks to the high ductility and dissipative capacity achieved by the bracing system. This favorable behavior is mainly due to the fasteners and materials used and to the correct application of the capacity design approach.

  14. Carbonate replacement of lacustrine gypsum deposits in two Neogene continental basins, eastern Spain

    Science.gov (United States)

    Anadón, P.; Rosell, L.; Talbot, M. R.

    1992-07-01

    Bedded nonmarine gypsum deposits in the Miocene Teruel and Cabriel basins, eastern Spain, are partly replaced by carbonate. The Libros gypsum (Teruel Graben) is associated with fossiliferous carbonate wackestones and finely laminated, organic matter-rich mudstones which accumulated under anoxic conditions in a meromictic, permanent lake. The gypsum is locally pseudomorphed by aragonite or, less commonly, replaced by calcite. Low δ 13C values indicate that sulphate replacement resulted from bacterial sulphate reduction processes that were favoured by anacrobic conditions and abundant labile organic matter in the sediments. Petrographic evidence and oxygen isotopic composition suggest that gypsum replacement by aragonite occurred soon after deposition. A subsequent return to oxidising conditions caused some aragonite to be replaced by diagenetic gypsum. Native sulphur is associated with some of these secondary gypsum occurrences. The Los Ruices sulphate deposits (Cabriel Basin) contain beds of clastic and selenitic gypsum which are associated with limestones and red beds indicating accumulation in a shallow lake. Calcite is the principal replacement mineral. Bacterial sulphate reduction was insignificant in this basin because of a scarcity of organic matter. Stable isotope composition of diagenetic carbonate indicates that gypsum replacement occurred at shallow burial depths due to contact with dilute groundwaters of meteoric origin. Depositional environment evidently has a major influence upon the diagenetic history of primary sulphate deposits. The quantity of preserved organic matter degradable by sulphate-reducing bacteria is of particular importance and, along with groundwater composition, is the main factor controlling the mechanism of gypsum replacement by carbonate.

  15. Hydrology of marginal evaporitic basins during the Messinian Salinity Crisis: isotopic investigation of gypsum deposits

    Science.gov (United States)

    El Kilany, Aida; Caruso, Antonio; Dela Pierre, Francesco; Natalicchio, Marcello; Rouchy, Jean-Marie; Pierre, Catherine; Balter, Vincent; Aloisi, Giovanni

    2016-04-01

    The deposition of gypsum in Messinian Mediterranean marginal basins is controlled by basin restriction and the local hydrological cycle (evaporation/precipitation rates and relative importance of continental vs marine water inputs). We are using the stable isotopic composition of gypsum as a proxy of the hydrological cycle that dominated at the moment of gypsum precipitation. We studied the Messinian Caltanissetta (Sicily) and Tertiary Piedmont (north western Italy) basins where we carried out a high-resolution isotopic study of gypsum layers composing gypsum-marl cycles. These cycles are thought to be the sedimentary expression of astronomical precession cycles, lasting approximately 20 kyr, during which the marginal basins experienced a succession of arid and a wet conditions. We determined the isotopic composition of gypsum hydration water (18O and D), of the sulphate ion (34S, 18O) and of Strontium (87/86Sr), all of which are potentially affected by the hydrological cycle. In our samples, the mother water from which gypsum precipitated is considerably lighter (-4.0 planning a detailed petrographic investigation of gypsum crystals to look for evidence of dissolution/precipitation processes at the micro-scale. This is an essential step in interpreting the isotopic signals of gypsum because we can expect the 18O and D composition of Messinian continental input to be not too dissimilar from that of modern meteoric waters involved in diagenetic processes.

  16. Utilization of ground waste seashells in cement mortars for masonry and plastering.

    Science.gov (United States)

    Lertwattanaruk, Pusit; Makul, Natt; Siripattarapravat, Chalothorn

    2012-11-30

    In this research, four types of waste seashells, including short-necked clam, green mussel, oyster, and cockle, were investigated experimentally to develop a cement product for masonry and plastering. The parameters studied included water demand, setting time, compressive strength, drying shrinkage and thermal conductivity of the mortars. These properties were compared with those of a control mortar that was made of a conventional Portland cement. The main parameter of this study was the proportion of ground seashells used as cement replacement (5%, 10%, 15%, or 20% by weight). Incorporation of ground seashells resulted in reduced water demand and extended setting times of the mortars, which are advantages for rendering and plastering in hot climates. All mortars containing ground seashells yielded adequate strength, less shrinkage with drying and lower thermal conductivity compared to the conventional cement. The results indicate that ground seashells can be applied as a cement replacement in mortar mixes and may improve the workability of rendering and plastering mortar.

  17. Effect of Tai Chi exercise in combination with auricular plaster on patients with lumbar muscle strain.

    Science.gov (United States)

    Lu, Tao; Song, Qing-Hua; Xu, Rong-Mei; Zhang, Li-Yan

    2015-01-01

    observe the effect of Tai Chi exercise on the patients with the chronic lumbar muscle strain under the intervention treatment of auricular plaster. 74 middle-aged and elderly patients, suffering from the chronic lumbar muscle strain, are randomly and equally divided into an observation group and a control group, with 37 patients in each group. The patients in the control group do Tai Chi exercise, while those in the observation group are treated by the auricular plaster therapy in addition to Tai Chi exercise. Evaluate and compare the disease conditions of the patients in the two groups before the treatment and after 12 weeks' treatment. after 12 weeks' treatment, the patients in the two groups have been improved differently in comparison with those before the treatment (P plaster therapy.

  18. Influence of Auricular Plaster Therapy on Sleeping Structure in OSAS Patients

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-hong; XIAO Lan-ying; WANG Bao-fa; YUAN Ya-dong; PAN Wen-sen; SHI Yu-zhen

    2009-01-01

    To evaluate the therapeutic effects of auricular plaster therapy for obstructive sleep apnea syndrome (OSAS) and the influence on sleeping structure. Methods: 45 OSAS patients were randomly divided into a treatment group of 30 cases and a control group of 15 cases for comparison of the changes in parameters of respiration and sleep at night. Results: The auricular plaster therapy significantly improved the hypoventilation index, respiratory disturbance index and other respiratory parameters as well as the sleeping parameters such as the time and rate of sleep at stage Ⅰ and Ⅱ, and the waking time and rate.Conclusion: Auricular plaster therapy may show good therapeutic effects for OSAS, and with the advantages of low cost and less side effects.

  19. [Ambulatory prevention of thrombosis with low molecular weight heparin in plaster immobilization of the lower extremity].

    Science.gov (United States)

    Kock, H J; Schmit-Neuerburg, K P; Hanke, J; Hakmann, A; Althoff, M; Rudofsky, G; Hirche, H

    1993-06-01

    Plaster cast immobilisation following trauma is a major risk factor for the development of deep vein thrombosis. In our controlled, randomized and prospective study on patients with minor injuries incidence of DVT in conservatively treated out-patients with plaster cast immobilisation of the leg was 3.9% in the control group (n = 126) without prophylaxis. By s.c. self-application of LMV heparin once daily the number of DVT in the prophylaxis group (n = 115) was reduced to 0. No severe side effects of NMH were observed. We conclude that thromboprophylaxis with LMW heparin once daily up to now conspiciously reduced the risk of DVT in outpatients with plaster cast immobilisation of the leg.

  20. CLINICAL OBSERVATION ON TREATMENT OF 61 CASES OF INSOMNIA WITH AURICULAR PLASTER THERAPY

    Institute of Scientific and Technical Information of China (English)

    张家彤; 王月

    2003-01-01

    Objective: To observe the therapeutic effect of auricular plaster (otopoint-pressure) therapy in thetreatment of insomnia. Methods: In this paper, 61 cases of insomnia patients including 16 males and 45 females weretreated with Ershenmen (MA-TF 1), Zhen (MA-AT), Yuanzhong (MA-AT), Nao Dian and E (MA-AT), combined withother otopoints according to symptoms. The otopoint was stuck with a piece of plaster adhered with vaccaria seeds andpressured by the patient him- or her-self. The treatment was given twice a week, with 7 times being a therapeuticcourse. Results: After 1 - 2 courses of treatment, 19 (31.15%) cases were cured, 34 (55.74 % ) had improvementand 8 (13.11%) had no changes, with the total effective rate being 86.9%. Conclusion: Auricular plaster therapyworks well in the treatment of insomnia patient.

  1. Monitoring of the moisture and salt load in restoration plasters in St.-Barbara' s church in Culemborg

    NARCIS (Netherlands)

    Hees, R.P.J. van; Sanders, M.M.

    2005-01-01

    St. Barbara's Church in Culemborg in the Netherlands has a history of moisture and salt damage to the plaster. In the past several restorations were performed, without a durable results. Finally, in 1997 test panels were applied in oreder to bas the choice for new plastering on in practice proved

  2. Evaluation of physical-mechanical properties of 3 brands of plaster of Paris in the Kenyan market.

    Science.gov (United States)

    Mwaniki, D L

    1990-05-01

    In this study, 3 brands of plaster of Paris that are available in the Kenyan Market for prosthetics and dental rehabilitation uses were subjected to physical-mechanical tests. The particles in two of the brands that had been imported were finer than a locally made plaster since less than 1.41% of their particles were larger than 150 microns compared to 15.2% in the local plaster. The range of their setting times was between 7.5 and 27.5 min. and was within the International Standards Organisation (ISO) recommendation. The water:power ratios required to produce plaster mixes of standard consistency for the locally made plaster was about 1.5 times of other brands. In compression, the mean 1-hour strength of local plaster was 2.5 MN/m2 (Mega Newtons per square metre) compared to 6.81 MN/m2 and 8.95 MN/m2 for the other brands. The differences between these strength values were highly significant (p less than 0.01). There were no significant differences in deformation of fracture for the 3 brands whose range was 1.32% to 1.71%. In order to obviate the need to import plaster, strict manufacturing techniques of locally made plaster are recommended.

  3. Hydrochemical features of groundwater in a coastal gypsum karst (Marina di Lesina, Gargano, Southern Italy) in relation to tides

    Science.gov (United States)

    Fidelibus, Maria Dolores; Campana, Claudia

    2014-05-01

    As part of a complex monitoring aimed at collecting suitable data for conceptual and numerical modelling of the coastal gypsum karst of Marina di Lesina (Gargano, Southern Italy), 64 groundwater samples were collected during three surveys at different depths from 9 monitoring wells aligned along two transects. The transects, perpendicular to the Acquarotta canal, are less of 1 Km long. The canal is directly connected to the sea and to the Lesina Lagoon and behaves as an oscillating border following sea tides. The sampling campaigns were carried out concurrently to phases of increasing, decreasing, and low tide and provide different frameworks of the chemical composition of ground waters. TDS (Total Dissolved Solids) of ground water samples ranges from 0.2 g/l to 35 g/l and increases generally along the flow lines towards the canal, and downward. The concentrations of the major ions deviate from theoretical ones defined by non-reactive mixing lines, which have as saline end-member either standard seawater or local seawater sampled offshore.Owing to the multi-component character of the hydrochemical system, the cation concentrations are controlled by competition among concurrent water-rock interaction processes that overlap to non-reactive freshwater-saltwater (FW-SW) mixing, being even triggered and/or enhanced by the same mixing, with feedback loops: gypsum and calcite dissolution, ion exchange (with direction depending on hydrodynamic conditions mainly driven by tides, and justified due to the presence of clay in the gypsum bedrock), and dedolomitization. The geochemical study also highlights the involvement of saline ground waters belonging to regional circuits that develop in the huge Mesozoic carbonate basement. The study highlights that in the saturated thickness of the gypsum coastal aquifer closer to the coast, the hydrochemical system is extremely reactive and strongly influenced by the different groundwater hydraulic conditions induced by the tide phases.

  4. Effect of cotton padding on the setting properties of plaster slabs.

    Science.gov (United States)

    Barlow, D; Bansal, R; Barlow, T; Rhee, S J; Kuiper, J H; Makwana, N K

    2013-03-01

    Plaster of Paris (PoP) impregnated bandages have been used to maintain the position of bones and joints for over a century. Classically, wool dressing is applied to the limb before the PoP, which can then be moulded to the desired shape. A modification of this practice is to wrap the PoP bandages circumferentially in cotton before wetting and applying to the patient in an attempt to reduce inhalation of plaster dust and reduce mess. However, this may affect the water content of the cast and therefore also its setting properties and strength. This study compared the setting properties of PoP casts when used with and without cotton wrapping. Sixty specimens, compliant with the American Society for Testing and Materials standards for three-point bending tests, were prepared, with thirty wrapped in cotton. All were weighed before and after water immersion, and wrapped around a plastic cylinder to mimic limb application. Bending stiffness and yield strength was measured on a servohydraulic materials testing machine at 2, 6, 12, 24, 48 and 72 hours. The water content of cotton-wrapped plaster was significantly higher (50%) than that of standard plaster. It had significantly lower strength up to 24 hours and significantly lower stiffness up to 72 hours. The initial decrease in strength and stiffness of the cast wrapped in cotton may comprise the ability of the backslab to hold the joint or bone in an optimal position. Any modification of the standard plaster slab application technique should allow for the potential adverse effects on the plaster setting properties.

  5. Efficacy of the topical 5% lidocaine medicated plaster in the treatment of chronic post-thoracotomy neuropathic pain.

    Science.gov (United States)

    Sansone, Pasquale; Passavanti, Maria Beatrice; Fiorelli, Alfonso; Aurilio, Caterina; Colella, Umberto; De Nardis, Lorenzo; Donatiello, Valerio; Pota, Vincenzo; Pace, Maria Caterina

    2017-05-01

    To assess the efficacy of the topical 5% lidocaine medicated plaster (Versatis(®), Grünenthal GmbH, Aachen, Germany) in patients with post-thoracotomy neuropathic pain. Patients were randomized to receive the topical 5% lidocaine medicated plaster (n = 33) or non-medicated placebo plasters (n = 30) for 12 h every day for 8 weeks. Laser-evoked potentials (LEPs) were measured, and various questionnaires/scales completed. Numeric Rating Scale pain scores improved significantly (p plaster than in placebo recipients. The same was true for N2 and P2 LEP latency and amplitude, and other parameters. The study included neurophysiological findings and confirmed the efficacy of the topical 5% lidocaine medicated plaster in patients with chronic post-thoracotomy neuropathic pain.

  6. Light in the darkening on Naica gypsum crystals

    Energy Technology Data Exchange (ETDEWEB)

    Castillo-Sandoval, I.; Fuentes-Cobas, L. E.; Esparza-Ponce, H. E.; Carreno-Márquez, J.; Montero-Cabrera, M. E., E-mail: elena.montero@cimav.edu.mx [Centro de Investigación en Materiales Avanzados (CIMAV), Miguel de Cervantes 120, Chihuahua, Chih 31109, México (Mexico); Fuentes-Montero, M. E. [Facultad de Ciencias Químicas, Universidad Autónoma de Chihuahua, Campus Universitario#2, Circuito Universitario, C.P.31125, Chihuahua, Chih. México (Mexico); Reyes-Cortes, M. [Facultad de Ingeniería. Universidad Autónoma de Chihuahua, Campus Universitario#2, Circuito Universitario, C.P.31125, Chihuahua, Chih. México (Mexico)

    2015-07-23

    Naica mine is located in a semi-desertic region at the central-south of Chihuahua State. The Cave of Swords was discovered in 1910 and the Cave of Crystals 90 years later at Naica mines. It is expected that during the last century the human presence has changed the microclimatic conditions inside the cave, resulting in the deterioration of the crystals and the deposition of impurities on gypsum surfaces. As a contribution to the clarification of the mentioned issues, the present work refers to the use of synchrotron radiation for the identification of phases on these surfaces. All the experiments were performed at the Stanford Synchrotron Radiation Lightsource. Grazing incidence X-ray diffraction (GIXRD) and radiography-aided X-ray diffraction (RAXRD) experiments were performed at beamline 11-3. X-Ray micro-fluorescence (μ-SXRF) and micro-X-ray absorption (μ-XANES) were measured at beamline 2-3. Representative results obtained may be summarized as follows: a) Gypsum, galena, sphalerite, hematite and cuprite at the surface of the gypsum crystals were determined. b) The samples micro-structure is affected by impurities. c) The elemental distributions and correlations (0.6-0.9) of Cu, K, Fe, Mn, Pb, Zn, Ca and S were identified by μ-SXRF. The correlations among elemental contents confirmed the phase identification, with the exception of manganese and potassium due to the amorphous nature of some impurity compounds in these samples. The compounds hematite (Fe{sub 2}O{sub 3}), β-MnO{sub 2}, Mn{sub 2}O{sub 3}, MnO and/or MnCO{sub 3}, PbS, PbCO{sub 3} and/or PbSO4, ZnO{sub 4}, ZnS and/or smithsonite (ZnCO{sub 3}), CuS + Cu Oxide were identified by XANES. Plausibly, these latter compounds do not form crystalline phases.

  7. Luminescence of Speleothems in Italian Gypsum Caves: Preliminary Report

    CERN Document Server

    Shopov, Yavor Y; Forti, Paolo

    2009-01-01

    The luminescence of 3 speleothem samples from the Acquafredda karst system and 1 from the Novella Cave (Gessi Bolognesi Natural Park, Italy) has been recorded using excitation by impulse Xe- lamp. All these carbonate speleothems are believed to be formed only from active CO2 from the air, because the bedrock of the cave consist of gypsum and does not contain carbonates. The obtained photos of luminescence record the climate changes during the speleothem growth. U/Th and 14C dating proved that studied speleothems started to grow since about 5,000 years ago. The detailed analyses of the luminescence records is still in progress.

  8. Synthesis of partial stabilized cement-gypsum as new dental retrograde filling material

    Energy Technology Data Exchange (ETDEWEB)

    Sadhasivam, S. [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Division of Medical Engineering Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan (China); Chen, Jung-Chih [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Medical Device Innovation Center, National Cheng Kung University, Tainan,Taiwan (China); Savitha, S. [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Hsu, Ming-Xiang; Hsu, Chung-King [Institute of Materials Science and Engineering, National Taipei University of Technology, Taipei, Taiwan (China); Lin, Chun-Pin [School of Dentistry and Graduate Institute of Clinical Dentistry, College of Medicine, National Taiwan University and National Taiwan University Hospital, Taipei, Taiwan (China); Lin, Feng-Huei, E-mail: double@ntu.edu.tw [Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan (China); Division of Medical Engineering Research, National Health Research Institute, Zhunan, Miaoli County, Taiwan (China)

    2012-10-01

    The study describes the sol-gel synthesis of a new dental retrograde filling material partial stabilized cement (PSC)-gypsum by adding different weight percentage of gypsum (25% PSC + 75% gypsum, 50% PSC + 50% gypsum and 75% PSC + 25% gypsum) to the PSC. The crystalline phase and hydration products of PSC-gypsum were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis. The handling properties such as setting time, viscosity, tensile strength, porosity and pH, were also studied. The XRD and microstructure analysis demonstrated the formation of hydroxyapatite and removal of calcium dihydrate during its immersion in simulated body fluid (SBF) on day 10 for 75% PSC + 25% gypsum. The developed PSC-gypsum not only improved the setting time but also greatly reduced the viscosity, which is very essential for endodontic surgery. The cytotoxic and cell proliferation studies indicated that the synthesized material is highly biocompatible. The increased alkaline pH of the PSC-gypsum also had a remarkable antibacterial activity. - Highlights: Black-Right-Pointing-Pointer A new dental retrograde filling material PSC-gypsum was developed. Black-Right-Pointing-Pointer PSC-gypsum cement has shown excellent initial and final setting time as 15-35 min. Black-Right-Pointing-Pointer It not only improved the setting time but also retain the viscosity, 2 Pa{center_dot}s. Black-Right-Pointing-Pointer High alkaline pH of the cement had a remarkable antibacterial activity. Black-Right-Pointing-Pointer Cytotoxicity studies revealed that the synthesized material is highly biocompatible.

  9. Limestone, gypsum, and magnesium oxide influence restoration of an abandoned Appalachian pasture

    Energy Technology Data Exchange (ETDEWEB)

    Ritchey, K.D.; Snuffer, J.D. [USDA ARS, Beaver, WV (United States). Appalachian Farming Systems Research Centre

    2002-07-01

    When restoring abandoned pastures on acidic hill-land soils to productivity, it is important to bring soil Ca and Mg to adequate levels. Gypsum is a readily available Ca amendment that is sufficiently soluble to move rapidly into the soil when surface-applied. Gypsum has been shown to reduce detrimental effects of subsurface acidity in soils of the southeastern USA. A 4-yr experiment was initiated to measure effects of surface gypsum application on forage production and to evaluate Mg-containing amendments to avoid gypsum-induced Mg deficiency. The study site was a southern West Virginia Gilpin silt loam (fine-loamy, mixed, mesic, Typic Hapludult) where abandoned hill-and pasture was being restored to productivity. Treatments included 0, 1000, 8000; 16 000, and 32 000 kg/ha flue gas desulfurization coal combustion by-product gypsum (gypsum) together with dolomitic limestone and five additional treatments to evaluate sources of supplemental Mg. Application of 16 000 kg/ha gypsum together with limestone increased forage yields of mixed orchardgrass (Dactylis glomerata L.) and tall fescue (Festuca arundinacea Schreb) pasture during establishment by 42% and production by 11% compared with limestone alone. About 8% of the mean 790 kg/ha yield increase could be attributed to acidity-neutralizing effects of alkaline constituents in the gypsum by-product. Plants in higher gypsum treatments had higher concentrations of K and P, but gypsum application decreased soil and plant Mg concentrations. This indicated that gypsum should not be applied on typical acid soils without supplemental Mg.

  10. Compósitos à base de gesso com resíduos de EVA e vermiculita Gypsum-based composites with EVA waste and vermiculite

    Directory of Open Access Journals (Sweden)

    Marilia P. de Oliveira

    2012-06-01

    Full Text Available O gesso é um dos materiais de construção mais antigos de que se tem conhecimento. Algumas de suas propriedades lhes conferem vantagens, tais como resistência ao fogo e isolamentos térmico e acústico. Objetivou-se, com este trabalho, avaliar as propriedades físico-mecânicas de compósitos à base de gesso com a incorporação de resíduos da indústria de calçados, o etileno acetato de vinila (EVA e a vermiculita. O desenvolvimento desses compósitos tem como propósito a produção de elementos de revestimento para proteção térmica de alvenarias. Para determinar a influência dos teores de resíduo de EVA e vermiculita e da relação água/gesso nas propriedades massa específica aparente e nas resistências a flexão e a compressão, foram incorporados cinco diferentes percentuais desses materiais, combinados com três relações água/gesso. Os resultados foram analisados por meio da estatística multivariável e indicaram que a massa específica aparente de ambos os compósitos e a resistência à flexão do compósito com vermiculita, mostraram maior dependência da relação água/gesso; por sua vez, o percentual de agregado apresentou maior influência na resistência à flexão do compósito com EVA e na resistência a compressão de ambos os compósitos.Gypsum is one of the oldest known building materials. Some of its properties confer advantages such as fire resistance, thermal and acoustic insulation. This work aims to study the physical and mechanical properties of gypsum-based composite with the incorporation of residues from the footwear industry ethylene vinyl acetate (EVA and vermiculite. The aim to develop these composites is to produce components for thermal protection of masonry. To determine the influence of different residue levels of EVA and vermiculite, and the water/plaster ratio on the bulk density, flexural and compressive strength, five different percentages of these materials were incorporated combined with

  11. Direct nanoscale observations of the coupled dissolution of calcite and dolomite and the precipitation of gypsum.

    Science.gov (United States)

    Offeddu, Francesco Giancarlo; Cama, Jordi; Soler, Josep Maria; Putnis, Christine V

    2014-01-01

    In-situ atomic force microscopy (AFM) experiments were performed to study the overall process of dissolution of common carbonate minerals (calcite and dolomite) and precipitation of gypsum in Na2SO4 and CaSO4 solutions with pH values ranging from 2 to 6 at room temperature (23 ± 1 °C). The dissolution of the carbonate minerals took place at the (104) cleavage surfaces in sulfate-rich solutions undersaturated with respect to gypsum, by the formation of characteristic rhombohedral-shaped etch pits. Rounding of the etch pit corners was observed as solutions approached close-to-equilibrium conditions with respect to calcite. The calculated dissolution rates of calcite at pH 4.8 and 5.6 agreed with the values reported in the literature. When using solutions previously equilibrated with respect to gypsum, gypsum precipitation coupled with calcite dissolution showed short gypsum nucleation induction times. The gypsum precipitate quickly coated the calcite surface, forming arrow-like forms parallel to the crystallographic orientations of the calcite etch pits. Gypsum precipitation coupled with dolomite dissolution was slower than that of calcite, indicating the dissolution rate to be the rate-controlling step. The resulting gypsum coating partially covered the surface during the experimental duration of a few hours.

  12. Gypsum's influence on corn yield and p loss from an eroded southern piedmont soil

    Science.gov (United States)

    Gypsum (CaSO4) has been shown to reduce dissolved P in surface water runoff from pastures fertilized with poultry litter (PL). However, limited research has evaluated gypsum’s influence on P loss under row crops. Moreover, can gypsum effectively reduce P loss when applied only to grass buffer strips...

  13. The Growth of Gypsum in the Presence of Hexavalent Chromium: A Multiscale Study

    Directory of Open Access Journals (Sweden)

    Juan Morales

    2016-03-01

    Full Text Available The sorption of dissolved inorganic pollutants into the structure of minerals is an important process that controls the mobility and fate of these pollutants in the Earth’s crust. It also modifies the surface structure and composition of the host mineral, affecting its crystallization kinetics. Here, we investigate the effect of hexavalent chromium, Cr(VI, on the nucleation and growth of gypsum by conducting two types of experiments: (i in situ atomic force microscopy (AFM observations of the growth of gypsum {010} surfaces in the presence of Cr(VI and (ii gypsum precipitation experiments by mixing aqueous solutions containing variable amounts of Cr(VI. Gypsum precipitation is progressively delayed when occurring from solutions bearing increasing Cr(VI concentrations. Chemical analyses of gypsum precipitates show that gypsum incorporates small Cr(VI amounts that correlate with the content of this ion in the aqueous solution. Gypsum cell parameters variation reflects this incorporation. At the molecular scale, Cr(VI induces a slowdown of step advance rates on gypsum {010} surfaces accompanied by the roughening of nanostep edges and the so-called “template effect”. This effect involves the reproduction of the original nanotopography after the completion of individual advancing monolayers and appears as a general nanoscale phenomenon occurring during growth of solid solutions from aqueous solutions even in the case of compositionally-restricted solid solutions.

  14. Pre-contamination of new gypsum wallboard with potentially harmful fungal species

    DEFF Research Database (Denmark)

    Andersen, Birgitte; Dosen, Ina; Lewinska, Anna Malgorzata;

    2017-01-01

    Gypsum wallboard is a popular building material, but is also very frequently overgrown by Stachybotrys chartarum after severe and/or undetected water damage. The purpose of this study was to determine whether Stachybotrys and other fungi frequently isolated from wet gypsum wallboard are already p...

  15. Authigenic gypsum in a deep sea core from Southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.

    Authigenic gypsum has been encountered in a deep sea core RC9-157 from the southeastern Arabian Sea at a depth of 4111 m which is a zone of lysocline. The formation of gypsum in the deep sea region is attributed to the prevailing sulphate rich...

  16. Impact of FGD gypsum on soil fertility and plant nutrient uptake

    Science.gov (United States)

    Use of FGD gypsum is thought to improve soil productivity and increase plant production. Thus, a study was conducted to evaluate the effects of FGD gypsum on yield, plant nutrient uptake and soil productivity. The study was conducted on an established bermudagrass pasture. Poultry litter was applied...

  17. Microstructure and mechanical properties of gypsum composites reinforced with recycled cellulose pulp

    Directory of Open Access Journals (Sweden)

    Magaly Araújo Carvalho

    2008-12-01

    Full Text Available The use of waste fibers for the reinforcement of brittle matrices is considered opportune for the sustainable management of urban solid residues. This paper examines the microstructure and mechanical properties of a composite material made of gypsum reinforced with cellulose fibers from discarded Kraft cement bag. Two different kinds of gypsum were used, natural gypsum (NG and recycled gypsum (RG, both with an addition of 10% by mass of limestone. For the production of samples, slurry vacuum de-watering technique followed by pressing was evaluated revealing to be an efficient and innovative solution for the composites under evaluation. The composite was analyzed based on flexural strength tests, scanning electron microscopy (SEM imaging, secondary electron (SE detection, and pseudo-adiabatic calorimetry. The morphology of the fractured surfaces of flexural test samples revealed large gypsum crystals double the original size surrounding the fibers, but with the same overall aspect ratio. Natural fibers absorb large amounts of water, causing the water/gypsum ratio of the paste to increase. The predominance of fiber pullout, damaged or removed secondary layers and incrusted crystals are indicative of the good bonding of the fiber to the gypsum matrix and of the high mechanical resistance of composites. This material is a technically better substitute for the brittle gypsum board, and it stands out particularly for its characteristics of high impact strength and high modulus of rupture.

  18. An important tool with no instruction manual: A review of gypsum use in agriculture

    Science.gov (United States)

    Land application of gypsum has been studied and utilized in agriculture and environmental remediation for many years. Most of the published literature has focused on gypsum application impacts on soil properties rather than crop yields. This literature review was conducted to (i) gather results from...

  19. Pre-contamination of new gypsum wallboard with potentially harmful fungal species

    DEFF Research Database (Denmark)

    Andersen, Birgitte; Dosen, Ina; Lewinska, Anna Malgorzata

    2017-01-01

    Gypsum wallboard is a popular building material, but is also very frequently overgrown by Stachybotrys chartarum after severe and/or undetected water damage. The purpose of this study was to determine whether Stachybotrys and other fungi frequently isolated from wet gypsum wallboard are already p...

  20. Far infrared emitting plaster in knee osteoarthritis: a single blinded, randomised clinical trial

    Directory of Open Access Journals (Sweden)

    N. Marino

    2012-12-01

    Full Text Available Objective. Therapeutic approach of osteoarthritis (OA still represents a challenge in clinical practice. The aim of the study is to assess the efficacy of far infrared (FIR emitting plaster in the treatment of knee OA. Design. This is a randomized, single-blind, placebo-controlled, parallel group with equal randomization (1:1, clinical trial. Patients affected by knee OA were randomly allocated to 1 of 2 treatment groups, either placebo plaster or far infrared emitting plaster. Primary endpoint was to assess pain improvement from baseline to 1 months posttreatment in the visual analogue score (VAS. Secondary end point was to evaluate pain score after 1 week of treatment and to compare ultrasonographic findings after 1 month of treatment. Results. Each group comprised 30 (in the FIR group and 30 (in the placebo group completers. VAS scores of the placebo and the FIR group were significantly lower at 1 week post-treatment (95% confidence interval CI = -1.14 to 0.31; PConclusions. Far infrared emitting plaster could be considered an effective non-pharmacological choice for the therapeutic management of knee OA.

  1. Fragmentation, Cost and Environmental Effects of Plaster Stemming Method for Blasting at A Basalt Quarry

    Science.gov (United States)

    Cevizci, Halim

    2014-10-01

    In this study, the plaster stemming application for blasting at a basalt quarry is studied. Drill cuttings are generally used in open pits and quarries as the most common stemming material since these are most readily available at blast sites. However, dry drill cuttings eject very easily from blastholes without offering much resistance to blast energy. The plaster stemming method has been found to be better than the drill cuttings stemming method due to increased confinement inside the hole and better utilization of blast explosive energy in the rock. The main advantage of the new stemming method is the reduction in the cost of blasting. At a basalt quarry, blasting costs per unit volume of rock were reduced to 15% by increasing burden and spacing distances. In addition, better fragmentation was obtained by using the plaster stemming method. Blast trials showed that plaster stemming produced finer material. In the same blast tests, +30 cm size fragments were reduced to 47.3% of the total, compared to 32.6% in the conventional method of drill cuttings stemming. With this method of stemming, vibration and air shock values increased slightly due to more blast energy being available for rock breakage but generally these increased values were small and stayed under the permitted limit for blast damage criteria unless measuring distance is too close.

  2. Treatment of localized neuropathic pain after disk herniation with 5% lidocaine medicated plaster

    Science.gov (United States)

    Likar, Rudolf; Kager, Ingo; Obmann, Michael; Pipam, Wolfgang; Sittl, Reinhard

    2012-01-01

    Objective To assess treatment with the 5% lidocaine medicated plaster for peripheral neuropathic pain after disk herniation. Study design Case series, single center, retrospective data. Patients and methods Data of 23 patients treated for neuropathic pain with the lidocaine plaster for up to 24 months after a protrusion or prolapse of the cervical, thoracic, or lumbar vertebral disks were retrospectively analyzed. Changes in overall pain intensity, in intensity of different pain qualities and of allodynia and hyperalgesia were evaluated. Results Patients (14 female/nine male, mean age 53.5 ± 10.4 years) presented with radiating pain into the abdomen, back, neck, shoulder, or legs and feet with a mean pain intensity of 8.3 ± 1.5 on the 11-point Likert scale. Mean treatment duration was 7.6 months; 52% of the patients received lidocaine plaster as monotherapy. At the end of the observation, mean overall pain intensity had been reduced to 3.1 ± 1.8. All other parameters also improved. The treatment was well tolerated. Conclusion These results point to a safe and effective treatment approach with 5% lidocaine medicated plaster for localized neuropathic pain related to disk herniation. However, owing to the small sample size, further investigation in a larger-scale controlled trial is warranted. PMID:22973116

  3. Mineralogical and textural characterization of mortars and plasters from the archaeological site of Barsinia, northern Jordan

    Directory of Open Access Journals (Sweden)

    Mustafa Mohammad AL-Naddaf

    2014-12-01

    Full Text Available Twelve mortar and plaster samples excavated in the archaeological site of Barsinia were mineralogically and petrographically examined by XRay Diffraction (XRD and Stereo and Polarized Light Microscopy, while the total carbonate content was measured using a DietrichFruhling Calcimeter. The physical properties of the samples, such as water uptake under atmospheric pressure and under vacuum, together with density and porosity, were measured. Only twelve samples were available for the purposes of this study: 8 plaster samples and 4 mortar samples. Eleven samples out of the total number of samples were mortars or plasters with lime binder and silica aggregate; calcite and quartz were identified in all of these samples. In most of the samples one or more pozzolanic components were detected; a hydraulic effect therefore exists in practically most of the studied mortars. Excluding the plasters taken from waterbearing constructions such as cisterns, and the mortar sample from the compact floor, the binder content is high; in general, the overall porosity of the studied samples is high. Porosity and petrographic investigation results suggest that the burning temperature of the limestone was low and/or the duration of the combustion was short; such preparation conditions produce a desirable quicklime. Owing to the significant compositional and textural differences between the samples that were reported, there is consequently no suitable general mortar that can be adopted for the restoration of the whole site.

  4. [Toxic mustard plaster dematitis and phototoxic dematitis after application of bergamot oil].

    Science.gov (United States)

    Weisenseel, P; Woitalla, S

    2005-12-15

    Two cases that illustrate the risks attendant on the therapeutic use of natural medications by laypersons are reported. In the first case, the application of a mustard plaster triggered toxic dermatitis. In the second case, a session in a solarium after the external application of bergamot oil resulted in a phototoxic reaction.

  5. Treatment of localized neuropathic pain after disk herniation with 5% lidocaine medicated plaster.

    Science.gov (United States)

    Likar, Rudolf; Kager, Ingo; Obmann, Michael; Pipam, Wolfgang; Sittl, Reinhard

    2012-01-01

    To assess treatment with the 5% lidocaine medicated plaster for peripheral neuropathic pain after disk herniation. Case series, single center, retrospective data. Data of 23 patients treated for neuropathic pain with the lidocaine plaster for up to 24 months after a protrusion or prolapse of the cervical, thoracic, or lumbar vertebral disks were retrospectively analyzed. Changes in overall pain intensity, in intensity of different pain qualities and of allodynia and hyperalgesia were evaluated. Patients (14 female/nine male, mean age 53.5 ± 10.4 years) presented with radiating pain into the abdomen, back, neck, shoulder, or legs and feet with a mean pain intensity of 8.3 ± 1.5 on the 11-point Likert scale. Mean treatment duration was 7.6 months; 52% of the patients received lidocaine plaster as monotherapy. At the end of the observation, mean overall pain intensity had been reduced to 3.1 ± 1.8. All other parameters also improved. The treatment was well tolerated. These results point to a safe and effective treatment approach with 5% lidocaine medicated plaster for localized neuropathic pain related to disk herniation. However, owing to the small sample size, further investigation in a larger-scale controlled trial is warranted.

  6. Microscale electrochemical cell using plaster (CaSO4 as liquid junction

    Directory of Open Access Journals (Sweden)

    Yuthapong Udnan

    2008-10-01

    Full Text Available A microscale apparatus for electrochemical cell in which plaster (CaSO4 was used as liquid junction has been developed. A glass tube (0.5 cm ID x 5.0 cm was used to prepare each half-cell. The potentials of the resulting galvanic cells were measured by a multimetre and were compared to those of the galvanic cells in which agar was used as liquid junction. It was found that the potentials produced by the galvanic cells with plaster as liquid junction are not significantly different from those of the cells with agar as liquid junction and close to the theoretical values. In addition, when the developed apparatus was used for the study of electrolysis of potassium iodide solution, it was found that the electrolytic cell made from the microscale apparatus with plaster liquid junction can distinctly separate the reactions occurring at the anode and the cathode. Moreover, the lifetime of the plaster liquid junction is much greater than that of the agar liquid junction.

  7. Clinical Observation on Prevention of Bronchial Asthma with Plaster on Acupoints

    Institute of Scientific and Technical Information of China (English)

    YU Jin-long; ZHU Han-ting

    2008-01-01

    @@ Bronchial asthma is a most common and chronicillness which often relapses and has no cure at present.Acupuncture has its specific advantage in treatingasthma. The author prevented 29 cases of asthma innon-acute stage of attack with plaster on acupoints.Now it is reported as follows.

  8. Forty Cases of Insomnia Treated by Multi-output Electric Pulsation and Auricular Plaster Therapy

    Institute of Scientific and Technical Information of China (English)

    Liu Weizhe

    2007-01-01

    @@ The writer has treated 40 cases of insomnia by the method of multi-output electric pulsation in combination with auricular plaster therapy (with a seed of Vaccariae segetalis 王不留行 taped tightly to a particular ear point and pressed) and received satisfactory therapeutic effects. A report follows.

  9. Calcium sulfoaluminate (Ye'elimite) hydration in the presence of gypsum, calcite, and vaterite

    Energy Technology Data Exchange (ETDEWEB)

    Hargis, Craig W. [Department of Civil and Environmental Engineering, University of California, Berkeley, CA (United States); Telesca, Antonio [School of Engineering, University of Basilicata, Potenza (Italy); Monteiro, Paulo J.M., E-mail: monteiro@ce.berkeley.edu [Department of Civil and Environmental Engineering, University of California, Berkeley, CA (United States)

    2014-11-15

    Six calcium sulfoaluminate-based cementitious systems composed of calcium sulfoaluminate, calcite, vaterite, and gypsum were cured as pastes and mortars for 1, 7, 28 and 84 days. Pastes were analyzed with X-ray diffraction, thermogravimetric and differential thermal analyses. Mortars were tested for compressive strength, dimensional stability and setting time. Furthermore, pastes with a water/cementitious material mass ratio of 0.80 were tested for heat evolution during the first 48 h by means of isothermal conduction calorimetry. It has been found that: (1) both calcite and vaterite reacted with monosulfoaluminate to give monocarboaluminate and ettringite, with vaterite being more reactive; (2) gypsum lowered the reactivity of both carbonates; (3) expansion was reduced by calcite and vaterite, irrespective of the presence of gypsum; and (4) both carbonates increased compressive strength in the absence of gypsum and decreased compressive strength less in the presence of gypsum, with vaterite's action more effective than that of calcite.

  10. The gypsum-brushite system: crystallization from solutions poisoned by phosphate ions

    Science.gov (United States)

    Rinaudo, C.; Lanfranco, A. M.; Boistelle, R.

    1996-01-01

    Gypsum and a non-stoichiometric calcium phosphate sulphate hydrate (CPSH) were grown from solutions poisoned by phosphate ions. The pH ranged from 4.7 to 5.6 and the sulphate over phosphate ratios from 1.5 to 9. In some cases, when the phosphate concentration was high (30%-40%) CPSH was stable. When the phosphate concentration was lower (10%-20%), CPSH formed as first phase in association with gypsum, but dissolved as soon as gypsum crystallized and grew at its expense. In that case, gypsum contained up to 10% phosphate. On the other hand, when gypsum crystallized alone, as first phase, it did not contain detectable amounts of phosphate.

  11. Alleviation of Subsoil Acidity of Red Soil in Southeast China with Lime and Gypsum

    Institute of Scientific and Technical Information of China (English)

    SUNBO; R.MOREAU; 等

    1998-01-01

    Application of lime or gypsum is a common agricultrual practice to ameliorate soils with low pH which prohibits crop prduction,Its integrated effect on soil properties in a red soil derved from Quaternary red clay in Southeast China is discussed in this paper,Application of gypsum in the topsoil without leaching raised soil pH and promoted the production of soil NH4,but lime addition had a contrary effect.Generally,application of lime and /or gypsum has little on soil electrical properties.Gypsum had a little effect on soil exchange complex and its effect went down to 30 cm in depth ,The effect of lime reached only to 5 cm below its application layer.With leaching,Ca transferred from top soil to subsoil and decreased exchangeable Al in subsiol.Gypsum application led to a sharp decrease in soil exchangeable Mg but had no effect on K.

  12. Factors contributing to the temperature beneath plaster or fiberglass cast material

    Science.gov (United States)

    Hutchinson, Michael J; Hutchinson, Mark R

    2008-01-01

    Background Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints. Methods The temperature beneath various types (plaster, fiberglass, and fiberglass splints), brands, and thickness of cast material were measured after they were applied over thermometer which was on the surface of a single diameter and thickness PVC tube. A single layer of cotton stockinette with variable layers and types of cast padding were placed prior to application of the cast. Serial temperature measurements were made as the cast matured and reached peak temperature. Time to peak, duration of peak, and peak temperature were noted. Additional tests included varying the dip water temperature and assessing external insulating factors. Ambient temperature, ambient humidity and dip water freshness were controlled. Results Outcomes revealed that material type, cast thickness, and dip water temperature played key roles regarding the temperature beneath the cast. Faster setting plasters achieved peak temperature quicker and at a higher level than slower setting plasters. Thicker fiberglass and plaster casts led to greater peak temperature levels. Likewise increasing dip-water temperature led to elevated temperatures. The thickness and type of cast padding had less of an effect for all materials. With a definition of thermal injury risk of skin injury being greater than 49 degrees Celsius, we found that thick casts of extra fast setting plaster consistently approached dangerous levels (greater than 49 degrees for an extended period). Indeed a cast of extra-fast setting plaster, 20 layers thick, placed on a pillow during maturation maintained temperatures over 50 degrees of Celsius for over 20

  13. Factors contributing to the temperature beneath plaster or fiberglass cast material

    Directory of Open Access Journals (Sweden)

    Hutchinson Mark R

    2008-02-01

    Full Text Available Abstract Background Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints. Methods The temperature beneath various types (plaster, fiberglass, and fiberglass splints, brands, and thickness of cast material were measured after they were applied over thermometer which was on the surface of a single diameter and thickness PVC tube. A single layer of cotton stockinette with variable layers and types of cast padding were placed prior to application of the cast. Serial temperature measurements were made as the cast matured and reached peak temperature. Time to peak, duration of peak, and peak temperature were noted. Additional tests included varying the dip water temperature and assessing external insulating factors. Ambient temperature, ambient humidity and dip water freshness were controlled. Results Outcomes revealed that material type, cast thickness, and dip water temperature played key roles regarding the temperature beneath the cast. Faster setting plasters achieved peak temperature quicker and at a higher level than slower setting plasters. Thicker fiberglass and plaster casts led to greater peak temperature levels. Likewise increasing dip-water temperature led to elevated temperatures. The thickness and type of cast padding had less of an effect for all materials. With a definition of thermal injury risk of skin injury being greater than 49 degrees Celsius, we found that thick casts of extra fast setting plaster consistently approached dangerous levels (greater than 49 degrees for an extended period. Indeed a cast of extra-fast setting plaster, 20 layers thick, placed on a pillow during maturation maintained temperatures over 50 degrees of

  14. Well logging identification of gypsum cap rocks in middle-upper Yangtze region%中上扬子区膏岩盖层的测井识别

    Institute of Scientific and Technical Information of China (English)

    冯琼; 魏水建

    2011-01-01

    针对中、上扬子区膏岩盖层测井响应特征,充分利用地质、录井、岩心分析、测井等资料,采用岩心刻度测井的方法,建立了膏岩盖层参数测井解释模型,并对该区膏岩盖层进行了测井解释与评价;建立了一套适合川东北地区膏岩盖层的测井识别方法,从而实现了盖层从定性识别到盖层参数的定量评价,为盖层的地球物理预测研究提供了重要的基础参数.%Based on well logging response characteristics of gypsum cap rocks in the middle- upper Yangtze region, with geology, well logging, core analysis and logging data, it was established in this paper a logging interpretation model of gypsum cap rock parameters using the core calibration logging method.The gypsum cap rocks in the study region were interpreted and evaluated. A new set of logging identification method suitable for gypsum cap rocks in the Northeast Sichuan Basin was put forward. The qualitative identification and the quantitative evaluation of cap rocks were done, offering important basis parameters for the geophysical prediction researches of cap rocks.

  15. A quantitative analysis of IRT data for the evaluation of plaster degradation at the Dome of Magdeburg (Germany)

    Science.gov (United States)

    Di Maio, Rosa; Maierhofer, Christiane; Mancini, Cecilia; Piegari, Ester

    2013-04-01

    Infrared Thermography (IRT) is a helpful method for the nondestructive evaluation of artworks and buildings of historical interest since it is able to provide indications about most of degradation sources, such as alteration of material consistency, formation of microcracks, debondings, etc. The most used procedures for physical and geometrical characterization of the thermal anomaly sources are based on numerical models that solve the forward thermal problem, i.e. they find the solution of the Fourier differential equation, which describes the heat transfer in a medium. In this framework, we present a Finite Difference method to evaluate the conservation state of the Dome of Magdeburg (Germany). In particular, the study is focused on the analysis of the thermal images acquired on the east wing of the cloister from the 13th century, and is aimed to characterize its plaster score. The structure was heated with an infrared radiator and thermal images were acquired on both heating and cooling phase for fifteen minutes. The proposed conservative FD method allows taking into account for varying thermal conductivity, density and specific heat of defects and disrupted materials. The heat transfer problem is formulated in one and two dimensions and, therefore, it is able to characterize multi-layered structures. The investigated structure is made of three plaster layers (one lime wash layer that overlaps two lime mortar layers) and a sandstone background. Numerical simulations have shown a very good match between the experimental and theoretical curves for all the considered anomalous areas, for both 1D and 2D formulations, providing an average percentage error of the order of 10-1%. In particular, the study allowed to define thickness, depth and nature (density, thermal conductivity and specific heat) of the thermal anomaly sources, attributable to the degradation of the lime mortar layer at different depths. The application of the codes provided helpful indications for

  16. The role of biofilms in the sedimentology of actively forming gypsum deposits at Guerrero Negro, Mexico.

    Science.gov (United States)

    Vogel, Marilyn B; Des Marais, David J; Turk, Kendra A; Parenteau, Mary N; Jahnke, Linda L; Kubo, Michael D Y

    2009-11-01

    Actively forming gypsum deposits at the Guerrero Negro sabkha and saltern system provided habitats for stratified, pigmented microbial communities that exhibited significant morphological and phylogenetic diversity. These deposits ranged from meter-thick gypsum crusts forming in saltern seawater concentration ponds to columnar microbial mats with internally crystallized gypsum granules developing in natural anchialine pools. Gypsum-depositing environments were categorized as forming precipitation surfaces, biofilm-supported surfaces, and clastic surfaces. Each surface type was described in terms of depositional environment, microbial diversity, mineralogy, and sedimentary fabrics. Precipitation surfaces developed in high-salinity subaqueous environments where rates of precipitation outpaced the accumulation of clastic, organic, and/or biofilm layers. These surfaces hosted endolithic biofilms comprised predominantly of oxygenic and anoxygenic phototrophs, sulfate-reducing bacteria, and bacteria from the phylum Bacteroidetes. Biofilm-supported deposits developed in lower-salinity subaqueous environments where light and low water-column turbulence supported dense benthic microbial communities comprised mainly of oxygenic phototrophs. In these settings, gypsum granules precipitated in the extracellular polymeric substance (EPS) matrix as individual granules exhibiting distinctive morphologies. Clastic surfaces developed in sabkha mudflats that included gypsum, carbonate, and siliclastic particles with thin gypsum/biofilm components. Clastic surfaces were influenced by subsurface brine sheets and capillary evaporation and precipitated subsedimentary gypsum discs in deeper regions. Biofilms appeared to influence both chemical and physical sedimentary processes in the various subaqueous and subaerially exposed environments studied. Biofilm interaction with chemical sedimentary processes included dissolution and granularization of precipitation surfaces, formation of

  17. Diclofenac epolamine medicated plaster in the treatment of minor soft tissue injuries: a multicenter randomized controlled trial.

    Science.gov (United States)

    Li, Chunde; Frangione, Valeria; Rovati, Stefano; Zheng, Qingshan

    2013-09-01

    To investigate the efficacy and safety of a topical plaster containing diclofenac epolamine (DHEP) 1.3% in the treatment of patients with acute minor soft tissue injuries in China. This prospective, randomized, double blind, placebo-controlled study had balanced random assignment to DHEP medicated plaster and placebo plaster. A total of 384 patients, aged 18-74 years, with minor soft tissue injury occurring within 72 hours of study entry were enrolled and randomized. Plasters were applied twice daily for seven consecutive days. Outcomes were assessed in three visits over 7 days, in addition to patients' daily self-assessment and an adverse events follow-up visit on day 21. The primary efficacy endpoint was the mean change from baseline in pain on movement on a 100 mm Visual Analogue Scale (VAS) after 7 days of treatment. Secondary efficacy endpoints included pain on movement day-by-day evaluation, summed pain intensity difference, overall treatment efficacy, rescue medication consumption, and treatment tolerability. Reduction in pain on movement after 7 days of treatment, the primary efficacy endpoint, was statistically significantly greater in the DHEP plaster group than with placebo (reduction in VAS pain scores -53.78 ± 16.96 vs -37.02 ± 18.30 for DHEP vs placebo, p plaster was evident by day 1 and increased progressively throughout the treatment period. Global pain relief and overall treatment efficacy were significantly better with DHEP. Both DHEP and placebo plaster were well tolerated with few adverse events, mostly application site reactions. A medicated plaster containing DHEP applied to the affected site in Chinese patients with minor soft tissue injury, such as sprains, strains and contusions, was significantly more effective than placebo at reducing pain scores. Onset of action was rapid and the DHEP plaster was safe and well tolerated. The main limitation was the use of a subjective, though validated, self-reported VAS to assess the primary endpoint.

  18. Use of Ekibastuzsk coal ash as a filler for acid resistant plaster

    Energy Technology Data Exchange (ETDEWEB)

    Korsakov, F.F.; Isichenko, I.I.; Kabanov, G.A.

    1981-01-01

    Acid resistant plasters are used extensively at thermal power plants for protection of gas conduits, ash traps with spouts and hydraulic valves, and the internal surfaces of smoke pump housings. The surface being protected is preliminarily cleaned and a No. 16-20 steel grid attached to the surface by electrial welding. In producing the acid resistant plaster, 14-17 parts by weight of sodium silicofluoride are added to 100 parts by weight of sodium water glass; the remainder consists of andesite or diabase meal to the required consistency. The water glass fulfills the role of a binder; the sodium silicofluoride accelerates solidification of the water glass and the andesite and diabase meal serve as fillers. We found, tested in the laboratory and used successfully (under experimental-industrial conditions) a substitute for andesite and diabase meal. This substitute was ash of Ekibastuzsk coal, which was not only comparable to the meal in regard to quality of the acid resistant plaster, but even exceeded andesite and diabase meal in regard to several qualitative indicators. At the present time, a formula is being developed for an acid resistant plaster produced on the basis of water glass, sodium silicofluoride and ash of Ekibastuzsk coal. In order to verify the possibility of using other ashes instead of andesite and diabase meal, we also tested, under laboratory conditions, acid resistant plasters using ash from thermal power plants (TPP's) also burning Karagandinsk, Kuuchekinsk, Kuznetsk and Kansko-Achinsk coals. In compositions produced with polymer binders, Kansko-Achinsk coal ash was one of the best fillers, providing the most favorable physico-mechanical properties of the composition.

  19. Gypsum effects on crop yield and chemistry of soil, crop tissue, and vadose zone water: A meta-analysis.

    Science.gov (United States)

    Gypsum has various potential benefits as a soil amendment, but data are lacking on gypsum effects on crop yields and on environmental impacts across diverse field sites. Gypsum studies were conducted in six states using a common design with three rates each of mined and flue gas desulfurization (FGD...

  20. XRD and mineralogical analysis of gypsum dunes at White Sands National Monument, New Mexico and applications to gypsum detection on Mars

    Science.gov (United States)

    Lafuente, B.; Bishop, J. L.; Fenton, L. K.; King, S. J.; Blake, D.; Sarrazin, P.; Downs, R.; Horgan, B. H.

    2013-12-01

    A field portable X-ray Diffraction (XRD) instrument was used at White Sands National Monument to perform in-situ measurements followed by laboratory analyses of the gypsum-rich dunes and to determine its modal mineralogy. The field instrument is a Terra XRD (Olympus NDT) based on the technology of the CheMin (Chemistry and Mineralogy) instrument onboard the Mars Science Laboratory (MSL) rover Curiosity which is providing the mineralogical and chemical composition of scooped soil samples and drilled rock powders collected at Gale Crater [1]. Using Terra at White Sands will contribute to 'ground truth' for gypsum-bearing environments on Mars. Together with data provided by VNIR spectra [2], this study clarifies our understanding of the origin and history of gypsum-rich sand dunes discovered near the northern polar region of Mars [3]. The results obtained from the field analyses performed by XRD and VNIR spectroscopy in four dunes at White Sands revealed the presence of quartz and dolomite. Their relative abundance has been estimated using the Reference Intensity Ratio (RIR) method. For this study, particulate samples of pure natural gypsum, quartz and dolomite were used to prepare calibration mixtures of gypsum-quartz and gypsum-dolomite with the 90-150μm size fractions. All single phases and mixtures were analyzed by XRD and RIR factors were calculated. Using this method, the relative abundance of quartz and dolomite has been estimated from the data collected in the field. Quartz appears to be present in low amounts (2-5 wt.%) while dolomite is present at percentages up to 80 wt.%. Samples from four dunes were collected and prepared for subsequent XRD analysis in the lab to estimate their composition and illustrate the changes in mineralogy with respect to location and grain size. Gypsum-dolomite mixtures: The dolomite XRD pattern is dominated by an intense diffraction peak at 2θ≈36 deg. which overlaps a peak of gypsum, This makes low concentrations of dolomite

  1. Constructive applications of composite gypsum reinforced with Typha Latifolia fibres

    Directory of Open Access Journals (Sweden)

    Garcia Santos, A.

    2004-03-01

    Full Text Available The present research analyses the possibility to reinforce gypsum using enea fibres (Typha Latifolia creating a compound material in wich the fibres contribute to increase mechanical resistance, producing as well a reduction of the weight and a possible regulation of the set time.

    La investigación presente analiza la posibilidad de reforzar los morteros de escayola mediante la utilización dé fibras de Typha Latifolia, creando un material compuesto en el que las fibras contribuyen al aumento de resistencia mecánica, a la vez que se produce una reducción del peso y una regulación de los tiempos de fraguado. Las propiedades de estos materiales hacen que, en determinadas aplicaciones, su utilización resulte ventajosa con respecto a materiales tradicionales.

  2. Calcium Sulfates at Gale Crater and Limitations on Gypsum Stability

    Science.gov (United States)

    Vantiman, D. T.; Martinez, G. M.; Rampe, E. B.; Bristow, T. F.; Blake, D. F.; Yen, A. H.; Ming, D. W.; Rapin, W.; Meslin, P. -Y.; Morookian, J. M.; hide

    2017-01-01

    The Mars Science Laboratory rover has been exploring sedimentary rocks of the Bradbury group and overlying Murray formation, as well as the unconformably overlying Stimson formation. Early in exploration, and continuing to present, there have been observations of many Ca-sulfate veins that cut all three stratigraphic units. The CheMin XRD instrument on Curiosity provides complete mineralogy for drilled or scooped samples, with explicit identification of gypsum, bassanite, and anhydrite (crystal structure of so-called "soluble anhydrite," or gamma-CaSO4, is so similar to bassanite that it can't be distinguished at CheMin 2-theta resolution; here we refer to these similar dehydrated forms simply as bassanite).

  3. Enhanced gypsum scaling by organic fouling layer on nanofiltration membrane: Characteristics and mechanisms.

    Science.gov (United States)

    Wang, Jiaxuan; Wang, Lei; Miao, Rui; Lv, Yongtao; Wang, Xudong; Meng, Xiaorong; Yang, Ruosong; Zhang, Xiaoting

    2016-03-15

    To investigate how the characteristics of pregenerated organic fouling layers on nanofiltration (NF) membranes influence the subsequent gypsum scaling behavior, filtration experiments with gypsum were carried out with organic-fouled poly(piperazineamide) NF membranes. Organic fouling layer on membrane was induced by bovine serum albumin (BSA), humic acid (HA), and sodium alginate (SA), respectively. The morphology and components of the scalants, the role of Ca(2+) adsorption on the organic fouling layer during gypsum crystallization, and the interaction forces of gypsum on the membrane surface were investigated. The results indicated that SA- and HA-fouled membranes had higher surface crystallization tendency along with more severe flux decline during gypsum scaling than BSA-fouled and virgin membranes because HA and SA macromolecules acted as nuclei for crystallization. Based on the analyses of Ca(2+) adsorption onto organic adlayers and adhesion forces, it was found that the flux decline rate and extent in the gypsum scaling experiment was positively related to the Ca(2+)-binding capacity of the organic matter. Although the dominant gypsum scaling mechanism was affected by coupling physicochemical effects, the controlling factors varied among foulants. Nevertheless, the carboxyl density of organic matter played an important role in determining surface crystallization on organic-fouled membrane.

  4. The Effect of Orthodontic Model Fabrication Procedures on Gypsum Materials.

    Science.gov (United States)

    1992-06-01

    Great Lakes Orthodontics , Ltd. Supply Catalog (1991-92), 97. 3. Dolphin Imaging System - Advertisement in the Journal of Clinical Orthodontics (1991). 4...Practice (1987), 5:119-123. 11. Roth, R. H.: Functional occlusion for the orthodontist - Parts I, II, III, IV. Journal of Clinical Orthodontics (1981...supportive tissues at a particular time. As Graber 43 noted in his orthodontic textbook, "after the clinical examination, there is no single more important

  5. Archaeomagnetic studies in central Mexico—dating of Mesoamerican lime-plasters

    Science.gov (United States)

    Hueda-Tanabe, Y.; Soler-Arechalde, A. M.; Urrutia-Fucugauchi, J.; Barba, L.; Manzanilla, L.; Rebolledo-Vieyra, M.; Goguitchaichvili, A.

    2004-11-01

    For the first time results of an archaeomagnetic study of unburned lime-plasters from Teotihuacan and Tenochtitlan in central Mesoamerica are presented. Plasters made of lime, lithic clasts and water, appear during the Formative Period and were used for a variety of purposes in floors, sculptures, ceramics and supporting media for mural paintings in the Oaxaca and Maya area. In Central Mexico, grinded volcanic scoria rich in iron minerals is incorporated into the lime-plasters mixture. Samples were selected from two archaeological excavation projects in the Teopancazco residential compound of Teotihuacan and the large multi-stage structure of Templo Mayor in Tenochtitlan, where chronological information is available. The intensity of remanent magnetization (natural remanent magnetization (NRM)) and low-field susceptibility are weak reflecting low relative content of magnetic minerals. NRM directions are well grouped and alternating field demagnetization shows single or two-component magnetizations. Rockmagnetic experiments point to fine-grained titanomagnetites with pseudo-single domain behavior. Anisotropy of magnetic susceptibility (AMS) measurements document a depositional fabric, with normal to free-surface minimum AMS axes. Characteristic mean site directions were correlated to the paleosecular variation curve for Mesoamerica. Data from Templo Mayor reflect recent tilting of the structures. Teopancazco mean site declinations show good correspondence with the reference curve, in agreement with the radiocarbon dating. Dates for four stages of Teotihuacan occupancy based on the study of lime-plasters range from AD 350 to 550. A date for a possible Mazapa occupation around AD 850 or 950 is also suggested based on the archaeomagnetic correlation. The archaeomagnetic record of a plaster floor in Teopancazco differed from the other nearby sites pointing to a thermoremanent magnetization; comparison with the reference curve suggests dates around AD 1375 or 1415. The

  6. Influence of shelf life on the setting time of type IV gypsum

    Science.gov (United States)

    Hapsari, M. L.; Irawan, B.; Damiyanti, M.

    2017-08-01

    Although expired materials can exhibit a deterioration in their properties, expired type IV gypsum can still be found on the market. In order to evaluate the influence of the shelf life on its setting time, two groups of type IV gypsum (GC Fuji rock EP) with different expiration dates were used in this research. The setting time tests were done in a mold using a Vicat Needle apparatus. The results of the statistical analysis showed a significant difference (p<0.05) between the two different expiration date groups. Therefore, the shelf life did influence the setting time of the type IV gypsum.

  7. Reliability of linear measurements on a virtual bilateral cleft lip and palate model

    NARCIS (Netherlands)

    Oosterkamp, B.C.M.; van der Meer, W.J.; Rutenfrans, M.; Dijkstra, P.U.

    2006-01-01

    Objective: To assess the reliability and validity of measurements performed on three-dimensional virtual models of neonatal bilateral cleft lip and palate patients, compared with measurements performed on plaster cast models. Materials and Methods: Ten high-quality plaster cast models of bilateral c

  8. Efficacy of betamethasone valerate medicated plaster on painful chronic elbow tendinopathy: a double-blind, randomized, placebo-controlled trial.

    Science.gov (United States)

    Frizziero, Antonio; Causero, Araldo; Bernasconi, Stefano; Papalia, Rocco; Longo, Mario; Sessa, Vincenzo; Sadile, Francesco; Greco, Pasquale; Tarantino, Umberto; Masiero, Stefano; Rovati, Stefano; Frangione, Valeria

    2016-01-01

    to investigate the efficacy and safety of a medicated plaster containing betamethasone valerate (BMV) 2.25 mg in patients with chronic elbow tendinopathy. randomized, double-blind, placebo-controlled study with assignment 2:2:1:1 to BMV medicated plaster applied daily for 12 hours, daily for 24 hours or matched placebo. 62 patients aged ≥18 years with chronic lateral elbow tendinopathy were randomized. The primary efficacy variable was pain reduction (VAS) at day 28. Secondary objectives included summed pain intensity differences (SPID), overall treatment efficacy and tolerability. mean reduction in VAS pain score at day 28 was greater in both BMV medicated plaster groups, -39.35±27.69 mm for BMV12-h and -36.91±32.50 mm for BMV24-h, than with placebo, -20.20±27.32 mm. Considering the adjusted mean decreases, there was a statistically significant difference between BMV12-h and placebo (p=0.0110). Global pain relief (SPID) and overall treatment efficacy were significantly better with BMV. BMV and placebo plasters had similar local tolerability and there were few treatment-related adverse events. BMV plaster was significantly more effective than placebo at reducing pain in patients with chronic elbow tendinopathies. The BMV plaster was safe and well tolerated.

  9. A detailed rock-magnetic and archeomagnetic study of lime-plasters from central Mexico

    Science.gov (United States)

    Soler-Arechalde, A. M.; Rodriguez, M.; Ramirez, O.; Gogichaishvili, A.; Caballero-Miranda, C.; Hueda-Tanabe, Y.; Urrutia-Fucugauchi, J.

    2003-04-01

    We carried out a reconnaissance rock-magnetic and archeomagnetic investigations of lime-plasters at some most important pre-Hispanic sites in Central Mexico. Both burned and unburned lime plasters (in total 30 samples) were analyzed from Teotihuacan, Tlatelolco, Santa Cruz Atizapan and Pañhu. The characteristic directions determined in this study are considered to be of primary origin. Thermomagnetic investigation show that the remanence is carried in most cases by magnetite or Ti-poor titanomagnetite. Unblocking temperature spectra and relatively high coercivity point to 'small' pseudo-single domain magnetic structure grains as responsible for remanent magnetization. Single-component, linear demagnetization plots were observed in most of cases. The mean site directions are consistent with the available reference master curve for Mesoamerica.

  10. Can we save a follow up appointment by leaving nylon sutures under plaster for 6 weeks

    Directory of Open Access Journals (Sweden)

    Randeep Aujla

    2010-02-01

    Full Text Available Randeep Aujla, Abhinav Gulihar, Andrew Chandraraj, Graham TaylorOrthopaedic Department, Glenfield Hospital, Groby Road, Leicester, EnglandBackground: The purpose of this study was to highlight the potential resource saving method of leaving nylon sutures under plaster for 6 weeks after forefoot surgery. Methods: We gathered patient data from 72 cases of forefoot surgery over a 5-year period and analyzed the complications encountered. Only patients who required at least 6 weeks of plaster were included.Results: There were two cases of wound infection and one of flap necrosis. The infection rates are comparable to previous studies into forefoot surgery infection rates. There was no difficulty in removing the sutures and scarring was not noted to be a problem.Conclusions: Financial, convenience and time benefits could be obtained if this technique was in common practice.Keywords: elective forefoot surgery, wound infections, wound complications, nylon sutures

  11. The effects of nicotine in dermal plaster on cognitive functions in patients with Alzheimer's disease.

    Science.gov (United States)

    Snaedal, J; Johannesson, T; Jonsson, J E; Gylfadottir, G

    1996-01-01

    Eighteen patients with probable Alzheimer's disease (NINCDS/ADRDA criteria) participated in a placebo-controlled, double-blind study, with a crossover design. The patients had mild or moderate dementia (MMSE = 20.3 +/- 4.6, range 12-28). The trial consisted of two 4-week periods with a 2-week washout period in between. Nicotine was given in the form of dermal plasters. Most of the patients tolerated the highest doses of 21 mg nicotine/24 h, but some received 14 mg/24 h. The effect was monitored with tests of short-term memory, verbal fluency, attention and psychomotor speed. Nicotine was also determined in the blood. Short-term memory improved significantly after 4 weeks of treatment, both on nicotine and placebo (p nicotine applied in the form of dermal plasters is of any significance in the treatment of memory deficits in patient with Alzheimer's disease.

  12. Can foot compression under a plaster cast prevent deep-vein thrombosis during lower limb immobilisation?

    Science.gov (United States)

    Domeij-Arverud, E; Latifi, A; Labruto, F; Nilsson, G; Ackermann, P W

    2013-09-01

    We hypothesised that adjuvant intermittent pneumatic compression (IPC) beneath a plaster cast would reduce the risk of deep-vein thrombosis (DVT) during post-operative immobilisation of the lower limb. Of 87 patients with acute tendo Achillis (TA) rupture, 26 were prospectively randomised post-operatively after open TA repair. The treatment group (n = 14) received two weeks of IPC of the foot for at least six hours daily under a plaster cast. The control group (n = 12) had no additional treatment. At two weeks post-operatively all patients received an orthosis until follow-up at six weeks. At two and six weeks the incidence of DVT was assessed using colour duplex sonography by two ultrasonographers blinded to the treatment. Two patients withdrew from the study due to inability to tolerate IPC treatment. An interim analysis demonstrated a high incidence of DVT in both the IPC group (9 of 12, 75%) and the controls (6 of 12, 50%) (p = 0.18). No significant differences in incidence were detected at two (p = 0.33) or six weeks (p = 0.08) post-operatively. Malfunction of the IPC leading to a second plaster cast was found to correlate with an increased DVT risk at two weeks (ϕ = 0.71; p = 0.019), leading to a premature abandonment of the study. We cannot recommend adjuvant treatment with foot IPC under a plaster cast for outpatient DVT prevention during post-operative immobilisation, owing to a high incidence of DVT related to malfunctioning of this type of IPC application.

  13. Who should answer the question: "Can I drive with this plaster cast?".

    Science.gov (United States)

    Gandhi, M J; Freitas, D; Lewis, M; Bolton, L; Bhasin, S; Leonard, D; Marsh, A

    2014-02-01

    The application of a plaster cast is known to affect driving ability, but patients continue to drive. The individuals and authorities involved in assessing driving safely include doctors, the Driver and Vehicle Licensing Agency (DVLA), police, insurance companies, and patients, but it is unclear who should take responsibility for the advice given, especially in the event of an accident. We contacted senior plaster technicians in 348 hospitals in the UK. We recorded their responses regarding advice given to patients on driving in specific casts. Sixteen motor insurance companies and 40 police forces were also contacted in order to canvass their opinions. 188 technician interviews (response rate 54%) were conducted. Only 10% of respondents offered advice unprompted; an average of 48% of patients asked for advice. 88% of respondents referred patients to their motor insurance companies, and also to the DVLA (11.7%), doctor (10.6%), or police (5.9%). Only 20.2% of plaster rooms provided written information. All insurance companies would insure patients provided the doctor had not explicitly objected to driving, but there was no consensus amongst the responses received from police. In the event of an accident after the treating doctor had advised against driving, insurance companies were likely to invalidate the policy, and the police would seek penalty punishment or prosecution. Although doctors are not specifically trained to assess the ability of patients to drive, insurance companies and police forces place the responsibility on doctors to advise patients. Since current evidence suggests plaster casts can impair driving ability, we suggest patients should be advised not to drive. Patients accept all responsibility if they continue to drive after receiving this specific advice and understanding its implications. Copyright © 2013 Royal College of Surgeons of Edinburgh (Scottish charity number SC005317) and Royal College of Surgeons in Ireland. Published by Elsevier

  14. Quality of Plaster Molding for Distal Radius Fractures Is Improved Through Focused Tuition of Junior Surgeons.

    Science.gov (United States)

    Ramoutar, Darryl N; Silk, Robert; Rodrigues, Jeremy N; Hatton, Mark

    2014-08-01

    Successful nonoperative management of distal radius fractures requires an adequately reduced fracture held in a well-molded cast. The purpose of this study was to determine whether a targeted teaching session to the same group of junior doctors led to objective improvement in fracture reduction and plaster molding and hence a decrease in the redisplacement of these fractures. Retrospective review. Level I academic trauma center. A retrospective review of all dorsally angulated distal radius fractures treated in plaster that presented to our plaster room over a 4-week period (group 1, n = 52). This was followed by the intervention and a subsequent 4-week prospective review (group 2, n = 36). Radiographs were reviewed before manipulation, after manipulation, and at follow-up by a single senior orthopaedic trainee using predetermined criteria. A targeted teaching session on fracture reduction and cast molding to the same group of junior doctors involved in managing all these cases. Adequate fracture reduction, plaster molding, redisplacement, and further intervention before and after the targeted intervention. In group 1, 85% had adequate fracture reduction but only 36% showed adequate molding. This was improved in group 2%-94% adequate reduction and 65% adequate molding (P = 0.022). The rate of redisplacement was improved from 65% to 44% in group 2. In both groups, the rate of redisplacement was around 20% for adequately reduced and molded fractures, compared with around 90% for adequately reduced but inadequately molded cases (P < 0.001). The rate of further intervention improved from 27% to 8% (P = 0.052). We recommend that specific teaching focusing on fracture reduction and molding techniques is included in orthopaedic juniors' induction teaching or as a separate session. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

  15. Effect of lipidmicrosphere prostaglandin combined with Shengji plaster on bedsore healing in III and IV degree

    Institute of Scientific and Technical Information of China (English)

    Su-Fang Gao; Qing-Fu Song; Shu-Ping Gao

    2016-01-01

    Objective:To observe the effect of lipidmicrosphere prostaglandin (Lipo PGE1) combined with Shengji plaster on the bedsore healing.Methods: A total of 100 patients with bedsores in III and IV degree who were admitted in our hospital from January, 2013 to January, 2015 were included in the study and divided into the observation group and the control group with 50 cases in each group according to different treatment protocols. The blood glucose, infection, and blood pressure in the two groups were effectively controlled. The patients in the observation group were given intravenous drip of Lipo PGE1 and external application of Shengji plaster, while the patients in the control group were given intravenous drip of Chuanxiongqin injection and external application of Shengji plaster. Four-week treatment was regarded as one course. The specimens on the wound surface of bedsores 1, 2, 3, and 4 weeks after treatment were collected. SABC developing method was used to observe the blood capillary density value (/10 HP). TcPO2 1 cm around the wound surface and the skin temperature were measured.Results:The blood capillary density values 1, 2, 3, and 4 weeks after treatment in the observation group were significantly higher than those in the control group (P<0.05). The bedsore wound surface skin temperature 2, 4, 6, and 8 h after medication in the observation group was significantly lower than that in the control group (P<0.05), while TcPO2 was significantly higher than that in the control group (P<0.05).Conclusions: Lipo PGE1 combined with Shengji plaster can effectively improve the blood circulation on the wound surface of bedsores, and promote the bedsore healing.

  16. The plaster plate becomes a air-conditioner; La plaque de platre se fait climatiseur

    Energy Technology Data Exchange (ETDEWEB)

    Lucat, Th.

    2005-09-01

    BASF company, in association with Knauf, has developed a plaster plate capable to regulate the indoor temperature of a room during summer time. A paraffin-based (wax) phase change material, named Micronal, is included in the plater to store energy during the day and to release it during the night. The lifetime of the phase change material is at least 30 years without loss of efficiency. Short paper. (J.S.)

  17. Treatment of localized neuropathic pain after disk herniation with 5% lidocaine medicated plaster

    OpenAIRE

    Likar, Rudolf; Kager, Ingo; Obmann,; Pipam, Wolfgang; Sittl,Reinhard

    2012-01-01

    Rudolf Likar,1 Ingo Kager,1 Michael Obmann,1 Wolfgang Pipam,1 Reinhard Sittl21Department of Anesthesiology and Intensive Care, Klagenfurt Hospital, Klagenfurt, Austria; 2Department of Anesthesiology, Interdisciplinary Pain Center, University Hospital Erlangen, Erlangen, GermanyObjective: To assess treatment with the 5% lidocaine medicated plaster for peripheral neuropathic pain after disk herniation.Study design: Case series, single center, retrospective data.Patients and methods: Data of 23 ...

  18. Development of Innovative Aerogel Based Plasters: Preliminary Thermal and Acoustic Performance Evaluation

    Directory of Open Access Journals (Sweden)

    Cinzia Buratti

    2014-09-01

    Full Text Available The thermal and acoustic properties of innovative insulating systems used as building coatings were investigated: Granular silica aerogel was mixed with natural plaster in different percentages. This coating solution is transpiring and insulating, thanks to the use of a natural lime coat and aerogel, a highly porous light material with very low thermal conductivity. The thermal conductivity of the proposed solution was evaluated by means of a Heat Flow meter apparatus (EN ISO 12667, considering different percentages of aerogel. The natural plaster without aerogel has a thermal conductivity of about 0.50 W/m K; considering a percentage of granular aerogel of about 90% in volume, the thermal conductivity of the insulating natural coating falls to 0.050 W/m K. Increasing the percentage of granular aerogel, a value of about 0.018–0.020 W/m K can be reached. The acoustic properties were also evaluated in terms of the acoustic absorption coefficient, measured by means of a Kundt’s Tube (ISO 10534-2. Two samples composed by a plasterboard support, an insulation plaster with aerogel (thicknesses 10 mm and 30 mm respectively and a final coat were assembled. The results showed that the absorption coefficient strongly depends on the final coat, so the aerogel-based plaster layer moderately influences the final value. The application of this innovative solution can be a useful tool for new buildings, but also for the refurbishment of existing ones. This material is in development: until now, the best value of the thermal conductivity obtained from manufacturers is about 0.015 W/m K.

  19. Observations on the Efficacy of Auricular-plaster Therapy plus Medicine in Treating Heroin Addiction

    Institute of Scientific and Technical Information of China (English)

    王泽涛; 袁宜勤; 王军; 罗杰坤

    2006-01-01

    Objective:To investigate the curative effect of auricular-plaster therapy on heroin addiction. Methods: Sixty cases of heroin addiction were treated by auricular-plaster therapy in cooperation with methadone and another 60 cases with methadone as a control. The treatment lasted 10 days. Results and conclusion: The results showed that the curative effect of auricular-plaster therapy plus methadone on heroin addiction was significantly better than that of methadone in the control group(P<0.01). The rate of drug relapse was also significantly lower in the former(P<0.01). It is considered that auricular-plaster therapy in cooperation with methadone is now an ideal therapeutic method for drug withdrawal.%目的:观察耳穴贴压治疗海洛因依赖的疗效.方法:耳穴贴压配合西药美沙酮治疗海洛因依赖60例,并与美沙酮治疗60例作对照,临床戒毒观察10 d.结果与结论:结果表明,耳穴贴压配合西药美沙酮戒毒疗效明显优于对照组美沙酮的戒毒疗效(P《0.01),其复吸率也低(P《0.01).认为耳穴贴压配合西药美沙酮戒毒是目前比较理想的戒毒治疗方法.

  20. Activation of Anhydrate Phosphogypsmn by K2SO4 and Hemihydrate Gypsum

    Institute of Scientific and Technical Information of China (English)

    YANG Min; QIAN Jueshi

    2011-01-01

    Lime pretreated phosphogypsum(PG) was calcined at 500 ℃ to produce anhydrate gypsum cement.Due to the slow hydration of anhydrate gypsum,additives,K2SO4 and hemihydrate gypsum were selected to accelerate the hydration of anhydrate.The hydration characteristics,the resistance to hydrodynamic water,and the mineralogical studies were investigated.The experimental results suggest that activated by K2SO4 and hemihydrate,anhydrate PG hydrates much more rapidly than that in the presence of only K2SO4 or in the absence of additives.The binder has proper setting time,good strength development,and relatively better resistance to water.The hardened binder has hydrated products of rod or stick like shaped dihydrate gypsum crystals.

  1. Investigation of the gypsum quality at three full-scale wet flue gas desulphurisation plants

    DEFF Research Database (Denmark)

    Hansen, Brian Brun; Kiil, Søren; Johnsson, Jan Erik

    2011-01-01

    In the present study the gypsum (CaSO4·2H2O) quality at three full-scale wet flue gas desulphurisation (FGD) plants and a pilot plant were examined and compared. Gypsum quality can be expressed in terms of moisture content (particle size and morphology dependent) and the concentration of residual...... or accumulation of fly ash and impurities from the sorbent. The crystal morphology obtained in the pilot plant was columnar with distinct crystal faces as opposed to the rounded shapes found at the full-scale plants. All the investigated full-scale plants consistently produced high quality gypsum (High purity......, low moisture content and low impurity content). An episode concerning a sudden deterioration in the gypsum dewatering properties was furthermore investigated, and a change in crystal morphology, as well as an increased impurity content (aluminium, iron and fluoride), was detected....

  2. Primary Evaporites for the Messinian Salinity Crisis: the shallow gypsum vs. deep dolomite formation paradox solved

    Science.gov (United States)

    De Lange, Gert J.; Krijgsman, Wout

    2014-05-01

    The Messinian Salinity Crisis (MSC) is a dramatic event that took place ~ 5.9 Ma ago, and resulted in the deposition of 0.3-3 km thick evaporites at the Mediterranean seafloor. A considerable and long-lasting controversy existed on the modes of their formation. During the CIESM Almeria Workshop a consensus was reached on several aspects. In addition, remaining issues to be solved were identified, such as for the observed shallow gypsum versus deep dolostone deposits for the early phase of MSC. The onset of MSC is marked by deposition of gypsum/sapropel-like alternations, thought to relate to arid/humid climate conditions. Gypsum precipitation only occurred at marginal settings, while dolomite containing rocks have been reported from deeper settings. A range of potential explanations have been reported, most of which cannot satisfactorily explain all observations. Biogeochemical processes during MSC are poorly understood and commonly neglected. These may, however, explain that different deposits formed in shallow versus deep environments without needing exceptional physical boundary conditions for each. We present here a unifying mechanism in which gypsum formation occurs at all shallow water depths but its preservation is mostly limited to shallow sedimentary settings. In contrast, ongoing anoxic organic matter (OM) degradation processes in the deep basin result in the formation of dolomite. Gypsum precipitation in evaporating seawater takes place at 3-7 times concentrated seawater; seawater is always largely oversaturated relative to dolomite but its formation is thought to be inhibited by the presence of dissolved sulphate. Thus the conditions for formation of gypsum exclude those for the formation of dolomite and vice versa. Another process that links the saturation states of gypsum and dolomite is that of OM degradation by sulphate reduction. In stagnant deep water, oxygen is rapidly depleted through OM degradation, then sulphate becomes the main oxidant for OM

  3. Heat transfer and thermal storage behaviour of gypsum boards incorporating micro-encapsulated PCM

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Chi-ming [Department of Civil Engineering, National Cheng-Kung University, 1, University Road, Tainan City 701 (China); Chen, R.H.; Lin, Ching-Yao [Department of Mechanical Engineering, Southern Taiwan University (China)

    2010-08-15

    In the application of energy storage and thermal environmental control, PCM (Phase Change Material) is a very promising material choice. This study incorporated mPCM (micro-encapsulated PCM) into gypsum to make mPCM gypsum board and then investigated the physical properties, heat transfer and thermal storage behaviour. The major control parameters are wall temperatures and the weight percentages of mPCM added to the gypsum boards. A melting fraction correlation, reduced from our test data and based on Stefan number (Ste), subcooling (Sb) and Fourier number, is proposed. It shows that case with a higher Ste or Sb can have a higher heat transfer through the hot wall. Thermal storage behaviour of mPCM gypsum boards is then analyzed. (author)

  4. Characterization of gypsum plasterboard with polyurethane foam waste reinforced with polypropylene fibers

    Directory of Open Access Journals (Sweden)

    L. Alameda

    2016-09-01

    Full Text Available Gypsum plasterboard that incorporates various combinations of polyurethane foam waste and polypropylene fibers in its matrix is studied. The prefabricated material was characterized in a series of standardized tests: bulk density, maximum breaking load under flexion stress, total water absorption, surface hardness, thermal properties, and reaction to fire performance. Polypropylene fibers were added to the polyurethane gypsum composites to improve the mechanical behavior of the plasterboard under loading. The results indicate that increased quantities of polymer waste led to significant reductions in the weight/surface ratio, the mechanical strength and the surface hardness of the gypsum, as well as improving its thermal resistance. The polypropylene fibers showed good adhesion to the polymer and the gypsum matrix, which enhanced the mechanical performance and the absorption capacity of these compounds. The non-combustibility test demonstrated the potential of the new material for use in internal linings.

  5. Fossil-fired steam/electric gypsum plant + wallboard plant + powerplant = win-win-win

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-06-01

    The Tennessee Valley Authority has invested in a wall board plant adjacent to its Cumberland power plant to process gypsum slurry. Synmat built the gypsum processing plant to dewater and concentrate the slurry to produce gypsum cake; Temple-Inland build a wallboard plant on 124 acres nearby, the two facilities being linked by conveyor. A 20-ft-high hill of gypsum that had accumulated since 1994 and 1999 when the wallboard plant was built is utilized to meet shortfalls in raw material. The slurry is retrieved from a 10-ft deep water-filled pit that was dug into the stockpile to accept an unmanned floating pump dredge and then pumped through a 6-in line to the Synmat plant. 3 photos.

  6. Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard

    Science.gov (United States)

    This page contains documents related to the evaluation of coal combustion residual beneficial use of fly ash concrete and FGD gypsum wallboard including the evaluation itself and the accompanying appendices

  7. Final Critical Habitat for the Gypsum wild-buckwheat (Eriogonum gypsophilum)

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — To provide the user with a general idea of areas where final critical habitat for gypsum wild-buckwheat (Eriogonum gypsophilum) occur based on the description...

  8. Gypsum-induced decay in granite monuments in Northwestern Spain

    Directory of Open Access Journals (Sweden)

    Silva Hermo, B.

    2010-03-01

    Full Text Available One of the most common forms of decay in granite monuments is the detachment of the superficial layer of the stone (plaques, plaquettes and scales. Previous studies of granite monuments in the northwest Iberian Peninsula revealed a direct relation between this type of weathering and the presence of calcium sulphate, and a mechanism whereby the salt causes this type of decay was suggested. In the present study, various hypotheses as regards the origin of the gypsum found in granite monuments are proposed. The study involved analysis of the contents of ions soluble in water, the results of X-ray diffraction analyses and the ratios of CaO/SO3 in samples of stone, mortar and deposits collected from different monuments. It was concluded that in most cases the gypsum originated from old paintworks or/and from the joint mortars, although inputs from other sources cannot be discounted, as discussed

    Una de las formas de deterioro más frecuente en los monumentos graníticos es la separación de la capa superficial de la piedra (placas, plaquetas y escamas. En trabajos anteriores centrados en monumentos del noroeste de la Península Ibérica, se constató la relación directa entre esta forma de alteración y la presencia de sulfato de calcio y se propuso el mecanismo a través del cual esta sal provoca este tipo de deterioro. En este trabajo se plantean varias hipótesis acerca del origen del yeso encontrado en monumentos graníticos. Para ello se comparan los contenidos de iones solubilizados en agua, los resultados de difracción de rayos X y las relaciones OCa/SO3 de muestras de piedra, morteros y depósitos recogidas en diferentes monumentos. Se llega a la conclusión de que en la mayor parte de los casos el yeso procede de antiguas pinturas o de revestimientos superficiales y de los morteros de juntas entre sillares, pero no se puede descartar la contribución de otros aportes, los cuales se discuten también en este artículo.

  9. Rehabilitation of gypsum-mined lands in the Indian desert

    Science.gov (United States)

    Sharma, K.D.; Kumar, S.; Gough, L.P.

    2001-01-01

    The economic importance of mining in the Indian Desert is second only to agriculture. Land disturbed by mining, however, has only recently been the focus of rehabilitation efforts. This research assesses the success of rehabilitation plans used to revegetate gypsum mine spoils within the environmental constraints of the north-west Indian hot-desert ecosystem. The rehabilitation plan first examined both mined and unmined areas and established assessments of existing vegetative cover and the quality of native soils and mine spoils. Tests were made on the effect of the use, and conservation, of available water through rainwater harvesting, amendment application (for physical and chemical spoil modification), plant establishment protocols, and the selection of appropriate germ plasm. Our results show that the resulting vegetative cover is capable of perpetuating itself under natural conditions while concurrently meeting the needs of farmers. Although the mine spoils are deficient in organic matter and phosphorus, they possess adequate amounts of all other nutrients. Total boron concentrations (>5.0 mg kg-1) in both the topsail and mine spoil indicate potentially phytotoxic conditions. Electrical conductance of mine spoil is 6-10 times higher than for topsail with a near-neutral pH. Populations of spoil fungi, Azotobactor, and nitrifying bacteria are low. The soil moisture storage in rainwater harvesting plots increased by 8% over the control and 48% over the unmined area. As a result of rehabilitation efforts, mine spoils show a steady buildup in organic carbon, and P and K due to the decomposition of farmyard manure and the contribution of nitrogen fixation by the established leguminous plant species. The rehabilitation protocol used at the site appears to have been successful. Following revegetation of the area with a mixture of trees, shrubs, and grasses, native implanted species have become established. Species diversity, measured in terms of species richness

  10. Objective assessment of plaster cast quality in pediatric distal forearm fractures: Is there an optimal index?

    Science.gov (United States)

    Labronici, Pedro José; Ferreira, Leonardo Termis; Dos Santos Filho, Fernando Claudino; Pires, Robinson Esteves Santos; Gomes, Davi Coutinho Fonseca Fernandes; da Silva, Luiz Henrique Penteado; Gameiro, Vinicius Schott

    2017-02-01

    Several so-called casting indices are available for objective evaluation of plaster cast quality. The present study sought to investigate four of these indices (gap index, padding index, Canterbury index, and three-point index) as compared to a reference standard (cast index) for evaluation of plaster cast quality after closed reduction of pediatric displaced distal forearm fractures. Forty-three radiographs from patients with displaced distal forearm fractures requiring manipulation were reviewed. Accuracy, sensitivity, specificity, false-positive probability, false-negative probability, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were calculated for each of the tested indices. Comparison among indices revealed diagnostic agreement in only 4.7% of cases. The strongest correlation with the cast index was found for the gap index, with a Spearman correlation coefficient of 0.94. The gap index also displayed the best agreement with the cast index, with both indices yielding the same result in 79.1% of assessments. When seeking to assess plaster cast quality, the cast index and gap index should be calculated; if both indices agree, a decision on quality can be made. If the cast and gap indices disagree, the padding index can be calculated as a tiebreaker, and the decision based on the most frequent of the three results. Calculation of the three-point index and Canterbury index appears unnecessary. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Dilatometric studies of plaster sandmix in raw and heat treated state

    Directory of Open Access Journals (Sweden)

    M. Pawlak

    2008-10-01

    Full Text Available Results of dilatometric studies of bounded plaster sandmix applied in precision pressure below atmospheric casting, are presented in this paper. Sandmix composed of half-hydrate α-CaSO4·2H2O with different parts of silica SiO2 was a subject of investigations. Silica is a factor weakening the influence of phase transformations on total distortion of the mould during heating and thus influences the accuracy of prepared cast. Experimental moulders of dimensions 7x35 made of plaster sandmix with silica fraction equal 30; 40; 50; 60 and 70% were used during studies. Sandmix was tested in raw state and after heat treatment changing the α-half hydrate into anhydrite II (CaSO4. It was demonstrated that addition of the silica at level about 50% influences most advantageously on dimension changes of heated sandmix by lowering dilatations 3 times in comparison with sandmix composed of pure α-half hydrate. The transformation of plaster structure into anhydrite II is also important - the shrinkability phase disappears and expansion similar to linear-like appears. It was determined that it is possible to obtain sandmix of small, stabile distortion on the way of appropriate selection of components and heat treatment parameters what improves dimensional and shape accuracy limits of the cast and significantly limits internal stresses in the mould eliminating risk of its cracking.

  12. Effect of Shengji Yuhong plaster on the wound healing after anal fistula surgery

    Institute of Scientific and Technical Information of China (English)

    Jin-Zhong Liu; Ma Li

    2016-01-01

    Objective:To observe the effect of Shengji Yuhong plaster on the wound healing after anal fistula surgery.Methods:A total of 120 patients with anal fistula who were admitted in our hospital from January, 2011 to December, 2013 for operation were included in the study and randomized into the observation group and the control group with 50 cases in each group after operation. The patients in the observation group were given external application of Shengji Yuhong plaster, while the patients in the control group were given vaselinum ribbon gauze. The patients in the two groups were given 3-week treatment. The wound area, granulation form, healing rate, healing time, and adverse reactions 1, 2, 3 weeks after operation in the two groups were compared.Results:The wound area 1, 2, 4 weeks after operation in the observation group was significantly less than that in the control group (P<0.05). The granulation form score was significantly lower than that in the control group (P<0.05). The wound repairing rate and the total effective rate were significantly higher than those in the control group (P<0.05), and the average healing time was significantly faster than that in the control group (P<0.05). Conclusions:Shengji Yuhong plaster can significantly shorten the wound healing time in patients after anal fistula surgery and is beneficial for the postoperative rehabilitation.

  13. The potential role of cattail-reinforced clay plaster in sustainable building

    Directory of Open Access Journals (Sweden)

    G. Georgiev

    2014-06-01

    Full Text Available Sustainable development is a key goal in town and country planning, as well as in the building industry. The main aims are to avoid inefficient land use, to improve the energy efficiency of buildings and, thus, to move towards meeting the challenges of climate change. In this article we consider how the use of a traditional low-energy building material, namely clay, might contribute. Recent research has identified a promising connection between the reinforcement of clay for internal wall plastering with fibres from the wetland plant Typha latifolia (cattail and the positive environmental effects of cultivating this species. If large quantities of Typha fibres were to be used in building, the need for cultivation of the plant would increase and create new possibilities for the renaturalisation of polluted or/and degraded peatlands. We explore the topic first on the basis of literature, considering the suitability of Typha for this application and possibilities for its sustainable cultivation, as well as implications for the life cycle analyses of buildings in which it is used. We then report (qualitatively the results of testing different combinations of clay with natural plant (straw and cattail fibres for their suitability as a universal plaster, which demonstrate clearly the superior properties of Typha fibres as a reinforcement material for clay plaster mortars.

  14. Utilization Alternatives and Potentiality for FGD Gypsum from Coal-Fired Power Plants

    Institute of Scientific and Technical Information of China (English)

    Tian Hezhong; Hao Jiming; Zhao Zhe; Kong Xiangying; Yang Chao; Lu Guangjie; Liu Hanqiang; Xu Fenggang; Chu Xue

    2006-01-01

    @@ It is estimated that an installed capacity of thermal power units with desulphurization equipment will come up to 40-50 GW by the end of 2020, which affords a good opportunity for opening up and development of the market of the by-product gypsum from thermal power desulphurization. Therefore, it is necessary to research the present situation and restrictive factors in the comprehensive utilization of FGD gypsum.

  15. Authigenic gypsum found in gas hydrate-associated sediments from Hydrate Ridge, the eastern North Pacific

    Institute of Scientific and Technical Information of China (English)

    WANG; Jiasheng; Erwin; Suess; Dirk; Rickert

    2004-01-01

    Characteristic gypsum micro-sphere and granular mass were discovered by binocular microscope in the gas hydrate-associated sediments at cores SO143-221 and SO143/TVG40-2A respectively on Hydrate Ridge of Cascadia margin, the eastern North Pacific. XRD patterns and EPA analyses show both micro-sphere and granular mass of the crystals have the typical peaks and the typical main chemical compositions of gypsum, although their weight percents are slightly less than the others in the non-gas hydrate-associated marine regions. SEM pictures show that the gypsum crystals have clear crystal boundaries, planes, edges and cleavages of gypsum in form either of single crystal or of twin crystals. In view of the fact that there are meanwhile gas hydrate-associated authigenic carbonates and SO42(-rich pore water in the same sediment cores, it could be inferred reasonably that the gypsums formed also authigenically in the gas hydrate-associated environment too, most probably at the interface between the downward advecting sulfate-rich seawater and the below gas hydrate, which spilled calcium during its formation on Hydrate Ridge. The two distinct forms of crystal intergrowth, which are the granular mass of series single gypsum crystals at core SO143/TVG40-2A and the microsphere of gypsum crystals accompanied with detrital components at core SO143-221 respectively, indicate that they precipitated most likely in different interstitial water dynamic environments. So, the distinct authigenic gypsums found in gas hydrate-associated sediments on Hydrate Ridge could also be believed as one of the parameters which could be used to indicate the presence of gas hydrate in an unknown marine sediment cores.

  16. OPTIMIZING THE COMPOSITION AND THE FEATURES OF GYPSUM BINDER PRODUCED IN A KETTLE

    Directory of Open Access Journals (Sweden)

    Pustovgar Andrey Petrovich

    2016-06-01

    Full Text Available The authors considered the gypsum binder obtained in a kettle SMA-158A in the enterprise LLC “MaykopGipsStroy”. The initial gypsum binder burnt at a temperature of 120 °Сwith the following unloading out of the kettle possessed unstable physical, mechanical and operational characteristics, that’s why the grade of gypsum binder was changed from G4-AII to G5-BII for different lots, which greatly reduced its application in the composition of dry mortars. It was stated, that instability of the features of gypsum binder is determined by the essential underburning of the system, which was characterized by residual content of calcium sulfate dihydrate in amount from 2 to 7 % by weight. In frames of the investigation the authors succeeded in raising the grade of the produced gypsum binder (from G4-5 to G6 due to optimization of the technological parameters of the burning process, as well as to stabilize the composition and features, to lay down temperature and time parameters allowing to control the technological process in order to obtain the gypsum binder with specified characteristics.

  17. Room-temperature electrolytic coloration and spectral properties of natural fibrous gypsum using a pointed anode

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Hongen, E-mail: jthgu@163.com; Hao, Xiaoqing; Tian, Pin

    2014-01-15

    Electrolysis experiments can be performed at room temperature and under various voltages using natural fibrous (NF) gypsum with a pointed anode and a flat cathode. The NF gypsum is colored electrolytically. SO{sub 4}{sup −}, SO{sub 3}{sup −}, SO{sub 2}{sup −}, O{sub 3}{sup −} and O{sup −} defect centers are produced in colored NF gypsum. The characteristic absorption bands of the defect centers are observed in the absorption spectra of the colored NF gypsum. The defect centers come mainly from electric-field-induced decomposition and/or direct electron loss of SO{sub 4}{sup 2−} radicals. Current is measured during electrolytic coloration. Electron exchanges from electron and charged radicals to electrodes induce complete current. -- Highlights: • We expanded the traditional electrolysis method. • Electrolysis experiments are performed at room temperature for the first time. • Natural fibrous gypsum is colored electrolytically. • SO{sub 4}{sup −}, SO{sub 3}{sup −}, SO{sub 2}{sup −}, O{sub 3}{sup −} and O{sup −} defect centers are produced in colored gypsum. • Defect centers come from electron transfers and decomposition of SO{sub 4}{sup 2−} radicals.

  18. Oxidation of North Dakota scrubber sludge for soil amendment and production of gypsum. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Hassett, D.J.; Moe, T.A.

    1997-10-01

    Cooperative Power`s Coal Creek Station (CCS) the North Dakota Industrial Commission, and the US Department of Energy provided funds for a research project at the Energy and Environmental Research Center. The goals of the project were (1) to determine conditions for the conversion of scrubber sludge to gypsum simulating an ex situ process on the laboratory scale; (2) to determine the feasibility of scaleup of the process; (3) if warranted, to demonstrate the ex situ process for conversion on the pilot scale; and (4) to evaluate the quality and handling characteristics of the gypsum produced on the pilot scale. The process development and demonstration phases of this project were successfully completed focusing on ex situ oxidation using air at low pH. The potential to produce a high-purity gypsum on a commercial scale is excellent. The results of this project demonstrate the feasibility of converting CCS scrubber sludge to gypsum exhibiting characteristics appropriate for agricultural application as soil amendment as well as for use in gypsum wallboard production. Gypsum of a purity of over 98% containing acceptable levels of potentially problematic constituents was produced in the laboratory and in a pilot-scale demonstration.

  19. Treatment of allergic rhinitis with acupoint herbal plaster: an oligonucleotide chip analysis.

    Science.gov (United States)

    Shiue, Horng-Sheng; Lee, Yun-Shien; Tsai, Chi-Neu; Chang, Hen-Hong

    2016-11-04

    Allergic rhinitis is regarded as an imbalanced Th1/Th2 cell-mediated response. The present study used microarray analysis to compare gene expression levels between allergic rhinitis patients before and after a series of acupoint herbal plaster applications. In this experimental pilot study, volunteers experiencing sneezing, runny nose, and congestion for more than 9 months in the year following initial diagnoses were included after diagnostic confirmation by otolaryngologists to exclude patients with sinusitis and nasal polyps. Patients with persistent allergic rhinitis each received four acupoint herbal plaster treatments applied using the moxibustion technique. Clinical outcomes were evaluated using the Rhinitis Quality of Life Questionnaire (RQLQ). Peripheral blood samples were analyzed using an ImmunoCAP Phadiatop test, and patients were classified as phadiatop (Ph)-positive or -negative. Microarray results were analyzed for genes that were differentially expressed between (1) Ph-positive and -negative patients treated with herbal plaster; and (2) before and after herbal plaster treatment in the Ph-positive patient group. Unsupervised and supervised methods were used for gene-expression data analysis. Nineteen Ph-positive and four Ph-negative participants with persistent allergic rhinitis were included in the study. RQLQ results indicated that the 19 Ph-positive volunteers experienced improvement in six of seven categories following acupoint herbal plaster treatments, whereas the four Ph-negative participants reported improvement in only two categories. Hierarchical clustering and principle component analysis of the gene expression profiles of Ph-positive and -negative participants indicated the groups exhibited distinct physiological responses to acupoint herbal treatment. Evaluation of gene networks using MetaCore identified that the "Immune response_IL-13 signaling via JAK-STAT" and the "Inflammation_Interferon signaling" were down- and up

  20. Study of heat and mass transfer of water evaporation in a gypsum board subjected to natural convection

    Science.gov (United States)

    Zannouni, K.; El Abrach, H.; Dhahri, H.; Mhimid, A.

    2016-12-01

    The present paper reports a numerical study to investigate the drying of rectangular gypsum sample based on a diffusive model. Both vertical and low sides of the porous media are treated as adiabatic and impermeable surfaces plate. The upper face of the plate represents the permeable interface. The energy equation model is based on the local thermal equilibrium assumption between the fluid and the solid phases. The lattice Boltzmann method (LBM) is used for solving the governing differential equations system. The obtained numerical results concerning the moisture content and the temperature within a gypsum sample were discussed. A comprehensive analysis of the influence of the mass transfer coefficient, the convective heat transfer coefficient, the external temperature, the relative humidity and the diffusion coefficient on macroscopic fields are also investigated. They all presented results in this paper and obtained in the stable regime correspond to time superior than 4000 s. Therefore the numerical error is inferior to 2%. The experimental data and the descriptive information of the approach indicate an excellent agreement between the results of our developed numerical code based on the LBM and the published ones.

  1. Study of heat and mass transfer of water evaporation in a gypsum board subjected to natural convection

    Science.gov (United States)

    Zannouni, K.; El Abrach, H.; Dhahri, H.; Mhimid, A.

    2017-06-01

    The present paper reports a numerical study to investigate the drying of rectangular gypsum sample based on a diffusive model. Both vertical and low sides of the porous media are treated as adiabatic and impermeable surfaces plate. The upper face of the plate represents the permeable interface. The energy equation model is based on the local thermal equilibrium assumption between the fluid and the solid phases. The lattice Boltzmann method (LBM) is used for solving the governing differential equations system. The obtained numerical results concerning the moisture content and the temperature within a gypsum sample were discussed. A comprehensive analysis of the influence of the mass transfer coefficient, the convective heat transfer coefficient, the external temperature, the relative humidity and the diffusion coefficient on macroscopic fields are also investigated. They all presented results in this paper and obtained in the stable regime correspond to time superior than 4000 s. Therefore the numerical error is inferior to 2%. The experimental data and the descriptive information of the approach indicate an excellent agreement between the results of our developed numerical code based on the LBM and the published ones.

  2. Diclofenac epolamine plus heparin plaster versus diclofenac epolamine plaster in mild to moderate ankle sprain: a randomized, double-blind, parallel-group, placebo-controlled, multicentre, phase III trial.

    Science.gov (United States)

    Costantino, Cosimo; Kwarecki, Jacek; Samokhin, Anatoly V; Mautone, Giuseppe; Rovati, Stefano

    2011-01-01

    In general sports, ankle sprain is the most frequently reported ankle injury and can cause chronic lateral ankle pain and tenderness. Treatment with NSAIDs is preferred, and several topical NSAID formulations are now available, helping to avoid the systemic adverse events typically associated with oral preparations. To compare the efficacy and tolerability of a newly developed fixed-dose diclofenac epolamine (diclofenac hydroxyethylpyrrolidine, DHEP)/heparin plaster (Flectoparin® Tissugel) with that of a DHEP (Flector EP Tissugel®) or placebo plaster in the treatment of mild to moderate ankle sprain in adults. This was a randomized, double-blind, parallel-group, placebo-controlled, multicentre, phase III study conducted in the emergency medical centres of hospitals or private clinics in Europe. Outpatients aged 18-65 years who had suffered an acute ankle sprain (O'Donoghue grade I or II in severity, with external lateral ligament involvement) within the previous 48 hours and had peri-malleolar oedema were eligible for inclusion. A total of 430 patients were randomized to receive a DHEP/heparin 1.3%/5600 IU (n = 142), DHEP 1.3% (n = 146) or placebo (n = 142) plaster, applied once daily to the injured ankle for a total of 7 days. The primary endpoint was the mean change from baseline in pain on movement on day 3, as measured by a visual analogue scale (VAS). The DHEP/heparin plaster was associated with a significantly (p = 0.002) greater mean reduction from baseline in pain on movement after 3 days of treatment than the DHEP plaster (-24.2 vs -18.8 mm VAS), with each active treatment providing significantly (p ≤ 0.005) greater pain relief than placebo (-13.7 mm VAS). Both DHEP/heparin and DHEP were also effective in relieving other measures of pain, with DHEP/heparin recipients experiencing significantly less daily pain while leaning on the injured limb than DHEP recipients (p plaster and DHEP plaster were both well tolerated, with

  3. Petrography of gypsum-bearing facies of the Codó Formation (Late Aptian, Northern Brazil

    Directory of Open Access Journals (Sweden)

    Jackson D.S. Paz

    2006-09-01

    Full Text Available An original and detailed study focusing the petrography of evaporites from the Late Aptian deposits exposed in the eastern and southern São Luís-Grajaú Basin is presented herein, with the attempt of distinguishing between primary and secondary evaporites, and reconstructing their post-depositional evolution. Seven evaporites phases were recognized: 1. chevron gypsum; 2. nodular to lensoidal gypsum or anhydrite; 3. fibrous to acicular gypsum; 4. mosaic gypsum; 5. brecciated gypsum or gypsarenite; 6. pseudo-nodular anhydrite or gypsum; and 7. rosettes of gypsum. The three first phases of gypsum display petrographic characteristics that conform to a primary nature. The fibrous to acicular and mosaic gypsum were formed by replacement of primary gypsum, but their origin took place during the eodiagenesis, still under influence of the depositional setting. These gypsum morphologies are closely related to the laminated evaporites, serving to demonstrate that their formation was related to replacements that did not affect the primary sedimentary structures. The pseudo-nodular anhydrite or gypsum seems to have originated by mobilization of sulfate-rich fluids during burial, probably related to halokinesis. The rosettes of gypsum, which intercept all the other gypsum varieties, represent the latest phase of evaporite formation in the study area, resulting from either intrastratal waters or surface waters during weathering.Neste trabalho, é apresentado um estudo original e detalhado enfocando os aspectos petrográficos dos evaporitos de depósitos aptianos superiores expostos no sul e leste da Bacia de São Luís-Grajaú. O objetivo é o estabelecimento de critérios que permitam distinguir entre evaporitos primários e secundários, além da reconstrução de sua evolução pós-deposicional. Sete fases de evaporitos foram reconhecidas: 1. gipsita em chevron; 2. gipsita ou anidrita nodular a lenticular; 3. gipsita fibrosa a acicular; 4. gipsita em

  4. Properties of mortars made by uncalcined FGD gypsum-fly ash-ground granulated blast furnace slag composite binder.

    Science.gov (United States)

    Zhong, Shiyun; Ni, Kun; Li, Jinmei

    2012-07-01

    A series of novel mortars were developed from composite binder of uncalcined FGD gypsum, fly ash (FA) and ground granulated blast furnace slag (GGBFS) for the good utilization of flue gas desulphurization (FGD) gypsum. At a fixed ratio (20%) of GGBFS to the composite binder, keeping consistency of the mortar between 9.5 and 10.0 cm, the properties of the composite mortar were studied. The results show that higher water/binder (W/B) is required to keep the consistency when increasing the percentage of FGD gypsum. No obvious influences of the W/B and content of FGD gypsum on the bleeding of paste were observed which keeps lower than 2% under all experimental conditions tried. The highest compressive and flexural strengths (ratio is 20% FGD gypsum, 20% GGBFS and 60% FA) are 22.6 and 4.3 MPa at 28 days, respectively. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) results indicate that massive ettringite crystals and C-S-H gels exist in the hydration products. At 90 days the mortars with FGD gypsum is dramatically smaller drying shrinkage (563-938 micro strain) than that without FGD gypsum (about 2250 micro strain). The release of the SO(4)(2-) from the mortar was analyzed, indicating that the dissolution of sulfate increases with FGD gypsum. The concentration of SO(4)(2-) releasing from the mortar with 10% FGD gypsum is almost equal to that obtained from the mortar without FGD gypsum. The release of SO(4)(2-) from the mortar with 20% FGD gypsum is 9200 mg·m(-2), which is lower than that from the mortar with 95% cement clinker and 5% FGD gypsum.

  5. Influence of different levels of gypsum on growth, herb and essential oil yields of lemongrass

    Directory of Open Access Journals (Sweden)

    Pandu Sastry Kakaraparthi

    2013-09-01

    Full Text Available The essential oil obtained from lemongrass (Cymbopogon flexuosus is an industrially important essential oil being used widely for the isolation of citral which can be converted into ionones. Improving the economic yield of the aromatic grass lemongrass is part of the rural development mandate of Central Institute of Medicinal and Aromatic Plants (CSIR-CIMAP. Salt affected soils occupy wide regions scattered all over the world and India has considerable salt-affected soils. The experiment was conducted on a red sandy loam soil at the research farm of CSIR-CIMAP, Hyderabad, India with five levels of gypsum as treatments(0-4 tons/ha.The soils of the experimental site are on the leeward side of an industrial area and the ground water has become saline due to industrial effluents. A field experiment was initiated to study the influence of gypsum in soil remediation and its influence on the growth and herb yield of lemongrass. Due to application of four tons of gypsum /ha a progressive decrease in the soil pH was observed and soil pH also decreased with advancement in time and it decreased from 7.73 to 7.40 at 120 days after planting due to gypsum application. EC increased progressively in all the treatments with time. The increase was less due to gypsum treatments. Similar trend was noticed in case of bicarbonate content of the soil and carbonates were absent in the soil. Gypsum application resulted in increased herb and essential oil yield of lemongrass due to better growth of plants(plant height, number of leaves /plant , number of tillers / clump and weight of plant / clump and the optimum dose of gypsum required is four tons/ha.

  6. Curative effect of Tai Chi exercise in combination with auricular plaster therapy on improving obesity patient with secondary hyperlipidemia.

    Science.gov (United States)

    Song, Qinghua; Yuan, Yandong; Jiao, Chun; Zhu, Ximei

    2015-01-01

    Observe the effect of Tai Chi in combination with auricular plaster therapy on treating obesity patient with secondary hyperlipidemia. Select 45 patients who suffer from simple obesity and secondary hyperlipidemia and then adopt random digital table to divide them into a Tai Chi group, an auricular plaster therapy group and a combination group. Each group consists of 15 patients. The patients in Tai Chi group are trained with Tai Chi twice a day, while those in auricular plaster therapy are treated with auricular plaster therapy 3-5 times a day and those in the combination group are trained with Tai Chi and auricular plaster therapy twice a day. BMI, body fat percentage and blood lipid indexes are respectively detected for the selected patients in the three groups before treatment and after 180 days' treatment. After 180 days' treatment, BMI index and body fat percentage of Tai Chi group are significantly improved in comparison with those before treatment (Pplaster therapy group are not improved obviously in comparison with those before the treatment (P>0.05) but the blood lipid index is improved significantly (Pplaster therapy can show the obvious synergistic therapeutic effect and thus the combined curative effect is obviously superior to that of the single therapy method.

  7. Can treatment success with 5% lidocaine medicated plaster be predicted in cancer pain with neuropathic components or trigeminal neuropathic pain?

    Science.gov (United States)

    Kern, Kai-Uwe; Nalamachu, Srinivas; Brasseur, Louis; Zakrzewska, Joanna M

    2013-01-01

    An expert group of 40 pain specialists from 16 countries performed a first assessment of the value of predictors for treatment success with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain. Results were based on the retrospective analysis of 68 case reports (sent in by participants in the 4 weeks prior to the conference) and the practical experience of the experts. Lidocaine plaster treatment was mostly successful for surgery or chemotherapy-related cancer pain with neuropathic components. A dose reduction of systemic pain treatment was observed in at least 50% of all cancer pain patients using the plaster as adjunct treatment; the presence of allodynia, hyperalgesia or pain quality provided a potential but not definitively clear indication of treatment success. In trigeminal neuropathic pain, continuous pain, severe allodynia, hyperalgesia, or postherpetic neuralgia or trauma as the cause of orofacial neuropathic pain were perceived as potential predictors of treatment success with lidocaine plaster. In conclusion, these findings provide a first assessment of the likelihood of treatment benefits with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain and support conducting large, well-designed multicenter studies.

  8. Functional exercise in combination with auricular plaster therapy is more conducive to rehabilitation of menopausal women patients with anxiety disorder.

    Science.gov (United States)

    Han, Yubin; Duan, Fugui; Xu, Rongmei; Wang, Yi; Zhang, Hongyu

    2015-01-01

    Observe the effect of functional exercise in combination with auricular plaster therapy on menopausal women patients with anxiety disorder. Select 45 menopausal women patients with anxiety disorder and then adopt random digital table to divide them into a functional exercise group, an auricular plaster therapy group and a combination group. Each group consists of 15 patients. The patients in the functional exercise group do yoga exercise twice a day; those in the auricular plaster therapy group are provided with the auricular plaster therapy twice a day; those in the combination group do yoga exercise and then they are provided with the auricular plaster therapy twice a day. Before the treatment and after 12 weeks' treatment, respectively detect and compare the selected patients in the three groups in respect HAMA score, physical function score and mental function score; And the cured patients are followed up for 3 months to compare recurrence rate of each group. After 12 weeks' treatment, HAMA score, physical function score and mental function score of the combination group are obviously better than those of another two groups (Pplaster, the combined curative effect is obviously better than that of single treatment and the clinical recurrence rate is significantly lower than that of single treatment. It shows that the combined treatment method presents obvious synergistic effect and the synergistic treatment is more beneficial to improve the curative effect.

  9. Flexible intramedullary nails with traction versus plaster cast for treating femoral shaft fractures in children: comparative retrospective study.

    Science.gov (United States)

    Nascimento, Fabiano Prata do; Santili, Cláudio; Akkari, Miguel; Waisberg, Gilberto; Braga, Susana dos Reis; Fucs, Patrícia Maria Moraes de Barros

    2013-01-01

    CONTEXT AND OBJECTIVE Femoral fractures are common in children between 2 and 12 years of age, and 75% of the lesions affect the femoral shaft. Traction followed by a plaster cast is universally accepted as conservative treatment. However, in some situations, a surgical approach is recommended. The objective here was to compare treatments for femoral shaft fractures using intramedullary nails (titanium elastic nails, TEN) versus traction and plaster casts in children. The hypothesis was that TEN might provide better treatment, with good clinical results in comparison with plaster casts. DESIGN AND SETTING This retrospective comparative study was conducted in a public university hospital. METHODS Sixty children with femoral fractures were evaluated; 30 of them underwent surgical treatment with TEN and 30 were treated conservatively using plaster casts. The patients' ages ranged from 5 to 13 years (mean of 9 years). RESULTS The mean duration of hospitalization was nine days for the surgical group and 20 days for the conservative group. The incidence of overgrowth in the patients treated with TEN was 60.0% and, for those treated conservatively, 13.3%. Partial weight-bearing was allowed after 3.5 weeks in the surgical group and after 9.6 weeks in the conservative group. New hospitalization was required for 90.0% in the surgical group and 16.7% in the conservative group. Patients treated with plaster casts presented higher incidence of complications, such as loss of reduction. CONCLUSIONS The surgical method presented better results for children.

  10. 5% Lidocaine Medicated Plaster for the Treatment of Postherpetic Neuralgia: A Review of the Clinical Safety and Tolerability.

    Science.gov (United States)

    Navez, Marie Louise; Monella, Christopher; Bösl, Irmgard; Sommer, Daniela; Delorme, Claire

    2015-06-01

    Postherpetic neuralgia (PHN) is a common, very painful, and often long-lasting complication of herpes zoster which is frequently underdiagnosed and undertreated. It mainly affects the elderly, many of whom are already treated for comorbidities with a variety of systemic medications and are thus at high risk of drug-drug interactions. An efficacious and safe treatment with a low interaction potential is therefore of high importance. This review focuses on the safety and tolerability of the 5% lidocaine medicated plaster, a topical analgesic indicated for the treatment of PHN. The available literature (up to June 2014) was searched for publications containing safety data regarding the use of the 5% lidocaine medicated plaster in PHN treatment; unpublished clinical safety data were also included in this review. The 5% lidocaine medicated plaster demonstrated good short- and long-term tolerability with low systemic uptake (3 ± 2%) and minimal risk for systemic adverse drug reactions (ADRs). ADRs related to topical lidocaine treatment were mainly application site reactions of mild to moderate intensity. The treatment discontinuation rate was generally below 5% of patients. In one trial, the 5% lidocaine medicated plaster was better tolerated than systemic treatment with pregabalin. The 5% lidocaine medicated plaster provides a safe alternative to systemic medications for PHN treatment, including long-term pain treatment.

  11. Can treatment success with 5% lidocaine medicated plaster be predicted in cancer pain with neuropathic components or trigeminal neuropathic pain?

    Science.gov (United States)

    Kern, Kai-Uwe; Nalamachu, Srinivas; Brasseur, Louis; Zakrzewska, Joanna M

    2013-01-01

    An expert group of 40 pain specialists from 16 countries performed a first assessment of the value of predictors for treatment success with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain. Results were based on the retrospective analysis of 68 case reports (sent in by participants in the 4 weeks prior to the conference) and the practical experience of the experts. Lidocaine plaster treatment was mostly successful for surgery or chemotherapy-related cancer pain with neuropathic components. A dose reduction of systemic pain treatment was observed in at least 50% of all cancer pain patients using the plaster as adjunct treatment; the presence of allodynia, hyperalgesia or pain quality provided a potential but not definitively clear indication of treatment success. In trigeminal neuropathic pain, continuous pain, severe allodynia, hyperalgesia, or postherpetic neuralgia or trauma as the cause of orofacial neuropathic pain were perceived as potential predictors of treatment success with lidocaine plaster. In conclusion, these findings provide a first assessment of the likelihood of treatment benefits with 5% lidocaine-medicated plaster in the management of cancer pain with neuropathic components and trigeminal neuropathic pain and support conducting large, well-designed multicenter studies. PMID:23630431

  12. 5% lidocaine medicated plaster double effect in a case of orofacial localized neuropathic pain

    Directory of Open Access Journals (Sweden)

    Casale R

    2014-11-01

    Full Text Available Roberto Casale,1,2 Yuriy Romanenko,2,3 Massimo Allegri4–6 1Department of Clinical Neurophysiology and Pain Rehabilitation Unit, Foundation "Salvatore Maugeri", Research and Care Institute, IRCCS, Pavia, Italy; 2EFIC Montescano Pain School, Montescano, Italy; 3Department of Neurology, Lugansk City Hospital 4, Lugansk, Ukraine; 4Department of Clinical, Surgical, Diagnostic and Pediatric Sciences University of Pavia, Pavia, Italy; 5Pain Therapy Service Fondazione IRCCS Policlinico San Matteo, Pavia, Italy; 6SIMPAR group, Pavia, Italy Abstract: Localized neuropathic pain (LNP is a type of neuropathic pain that is characterized by “consistent and limited area(s of maximum pain associated with negative or positive sensory signs and/or spontaneous symptoms characteristic of neuropathic pain”. This definition encompasses a huge number of neuropathic orofacial pain syndromes. We present a case report of a patient who was affected with sleep apnea syndrome treated with nocturnal oxygen mask delivery, in whom orofacial LNP hampered the wearing of a mask due to unbearable burning and throbbing pain. The application of 5% lidocaine medicated plaster during the night led to an impressive reduction of both the pain level and the size of the painful area due to the plaster's pharmacological mechanisms, which were associated with a secondary benefit due to its mechanical protective action. This case report shows how these two factors could be of clinical value and have to be considered more systematically in the treatment of LNP in reducing pain and the size of the painful area. Keywords: trigeminal pain, localized neuropathic pain, topical treatment, 5% lidocaine medicated plaster

  13. [Efficacy on borderline hypertension treated with acupuncture combined with anti-hypertensive plaster intervention].

    Science.gov (United States)

    Li, Yan-mei

    2014-11-01

    To compare the efficacy difference in treatment of borderline hypertension between acupuncture combined with anti-hypertensive plaster and simple acupuncture. Sixty patients of borderline hypertension were randomized into an observation group and a control group, 30 cases in each one. In the observation group, acupuncture was applied to Fengchi (GB 20), Taichong (LR 3) and the others, once a day, 5 treatments made one session. There were 2 days at interval among the sessions. Totally, 4 sessions were required. Additionally, in combination, the anti-hypertensive plaster was prepared with the fine powder of Chuanxiong (ligusticum wallichii) and Wuzhuyu (fructus evodiae) at 1.1 and mixed with vinegar. The plaster was applied to the umbilicus, once every two days, totally 15 times were required. In the control group, acupuncture was given simply. The selected acupoints and operation were the same as the observation group. Before and after treatment, blood pressure and syndrome score were observed and the short-term and long-term efficacies were assessed in the two groups. After treatment, the systolic pressure and diastolic pressure were reduced as compared with those before treatment in the two groups (all P0.05). In follow-up of the effective cases and remarkably effective cases in 3 months, the total effective rate in the observation group was 89.3% (25/28) and was 60.0% (15/25) in the control group, indicating the significant difference in comparison (Pplaster is the effective method in prevention and treatment of borderline hypertension. Regarding the long-term efficacy, this combined therapy achieves the superior improvement in the symptoms and physical signs of the patients of borderline hypertension as compared with simple acupuncture.

  14. Origin of zoning within dedolomite and calcitized gypsum of the Mississippian Arroyo Penasco Group

    Energy Technology Data Exchange (ETDEWEB)

    Ulmer, D.S.

    1985-01-01

    The Mississippian Arroyo Penasco Group carbonates are the oldest Paleozoic rocks present in north-central New Mexico. These supratidal to shallow,subtidal sediments exhibit complex diagenetic fabrics produced by periods of pre-Pennsylvanian subaerial exposure. Both extensive recrystallization of the Espiritu Santo carbonates and brecciation of the overlying Macho Member of the Tererro Formation resulted from an extended period of Mississippian subaerial exposure of broad, low-relief tidal flats. Cathodoluminescent petrography indicates that the recrystallized limestones consist of calcite pseudomorphs of dolomite and gypsum. Dedolomite and calcitized gypsum crystals, with /sup 13/C//sup 12/C ratios of -2 to +1.5% PDB, range from highly zoned to uniformly luminescent. Electron microprobe analyses reveals variable Mn and Fe contents across the pseudomorphs which are responsible for differences in observed luminosity. These features are interpreted to reflect a period of subaerial exposure after deposition of Macho Member sediments, which caused dissolution of gypsum and dolomite by sulfate and Mg depleted meteoric fluids and produced the collapse breccia. Preservation of zoning within some pseudomorphs required simultaneous dissolution of gypsum and dolomite and precipitation of calcite. C-isotope data indicates a meteoric to mixed phreatic origin for pore fluids which precipitated calcite; repetitive zoning within dolomite and gypsum pseudomorphs is indicative of interactions between marine and meteoric phreatic fluids in the intertidal environment.

  15. Crack Coalescence in Molded Gypsum and Carrara Marble: Part 2—Microscopic Observations and Interpretation

    Science.gov (United States)

    Wong, L. N. Y.; Einstein, H. H.

    2009-06-01

    Experimental uniaxial compression loading tests were conducted on molded gypsum and Carrara marble prismatic specimens to study the cracking and coalescence processes between pre-existing artificial flaws. The study showed that material had an influence on the cracking and coalescence processes (see the companion paper in this issue). As reported in the companion paper, one of the pronounced features as observed in the high-speed video recordings was the development of macroscopic white patches prior to the development of observable cracks in marble, but not in gypsum. This paper (part 2) deals with the microscopic aspects of the study. Specifically, the scanning electron microscope (SEM) and the environmental scanning electron microscope (ESEM) imaging techniques were used to study the microscopic development of white patches and their evolution into macroscopic tensile cracks and shear cracks in marble, and the microscopic initiation of hair-line tensile cracks and their evolution into macroscopic tensile cracks in gypsum. The microscopic imaging study in marble showed that the white patches were associated with extensive microcracking zones (process zones), while the extent of process zone development in gypsum was limited. The comparison of the macroscopic and microscopic results indicates that the different extent of microcracking zone development, related to the material textural properties, is a key factor leading to different macroscopic cracking behavior in gypsum and marble.

  16. Dispersebility degree influence of glass fibre E in the mechanical behaviour and workability of plaster

    Directory of Open Access Journals (Sweden)

    del Río Merino, M.

    2001-03-01

    Full Text Available Although there are many research studies about plaster strengthened with glass fibre E in Spain, there are no publications which advise the users (plasterers, manufacturers of prefabricated blocks or suspended ceilings, etc about the most appropriated types of fibre E in respect to its dispersebility degree in the matrix, its lengths, the percentage, or even the type of strengthening, etc. The study of the use of this strengthener is to achieve an improvement in the mechanical behaviour of plaster as well as better conditions in the paste workability. The company Vetrotex, with the technical personnel and together with the Department of Architectural Constructions and their control (E. U. A. T. M. have started a serious research on plaster strengthened with E fibre. Conclusions shown in this first article are about the influence of the dispersebility degree of glass fibres in the mechanical behaviour of the compound as well as its workability. The degree of dispersibility of the fibres in the matrix is closely related to the type of covering used in the production of the strengthening fibres.

    Aunque existen muchos trabajos de investigación sobre el refuerzo del yeso con fibra de vidrio E en España, no hay publicaciones que asesoren a los usuarios (aplicadores de yeso proyectado, fabricantes de prefabricados como bloques o falsos techos, etc. de los tipos défibra de vidrio E más adecuados, atendiendo a su grado de dispersabilidad en la matriz, las longitudes, el porcentaje, e incluso el tipo de refuerzo, etc., a efectos de conseguir un aumento del comportamiento mecánico del yeso/escayola y unas ciertas condiciones de trabajabilidad de la pasta. La empresa Vetrotex, a través de sus técnicos y en colaboración con el Departamento de Construcciones Arquitectónicas y su control (E. U. A. T. M., decide acometer un estudio en profundidad de la escayola reforzada con fibra de vidrio E. En este primer artículo se presentan las

  17. Internal plate fixation versus plaster in displaced complete articular distal radius fractures, a randomised controlled trial.

    Science.gov (United States)

    Mulders, Marjolein A M; Walenkamp, Monique M J; Goslings, J Carel; Schep, Niels W L

    2016-02-09

    Of all distal radius fractures, 25 % are complete articular fractures (AO/OTA type C fractures). Two thirds of those fractures are displaced and require reduction. According to several International Guidelines, adequately reduced intra-articular distal radius fractures are best treated non-operatively with plaster immobilisation, while surgical fixation is suggested only when the articular step exceeds 2 mm after reduction. However, these recommendations are based on studies that did not differentiate between intra- and extra-articular distal radius fractures. Thus, no clear consensus about the best treatment for patients with displaced intra-articular distal radius fractures can be reached. Despite the lack of evidence, an increase in internal fixation of intra-articular distal radius fractures has been observed over the last decade. The aim of this study is to determine the difference in functional outcome following open reduction and plate fixation compared with non-operative treatment with closed reduction and plaster immobilisation in patients with a displaced intra articular distal radius fracture. This multicentre randomised controlled trial will randomise between open reduction and internal plate fixation (intervention group) and closed reduction and plaster immobilisation (control group). All consecutive adult patients from 18 to 65 years with a displaced intra-articular distal radius fracture (AO/OTA type C), which has been adequately reduced at the Emergency Department according to the Dutch National Guidelines, are eligible for inclusion in this study. The primary outcome is function and pain of the wrist assessed with the Patient-Rated Wrist Evaluation score (PRWE). Secondary outcomes are the Disability of the Arm, Shoulder and Hand score (DASH), pain, quality of life (SF-36), range of motion, grip strength, radiological parameters, complications, crossovers and cost-effectiveness of both treatments. A total of 90 patients will be included in this

  18. Effects of Plaster of Paris waste on the mechanical properties of pottery

    Science.gov (United States)

    Badarulzaman, N. A.; Nawi, A. M.; Ibrahim, M.

    2015-05-01

    Ceramic waste may come from ceramics industry such as Plaster of Paris(POP) mould waste. The purpose of this study is to investigate the possibility of using POP as filler in the manufacturing of pottery. The different weight percentage of filler (0 wt.%, 2 wt.%,4 wt.%, 6wt.%, 8wt.%) content were added into the composition of pottery. The samples were characterized via viscosity test and bending test. The result of the study revealed that the weight percent of waste POP increase affects the physical properties with increasing the strength values.

  19. 5% lidocaine medicated plaster in elderly patients with postherpetic neuralgia: results of a compassionate use programme in France.

    Science.gov (United States)

    Clère, Florentin; Delorme-Morin, Claire; George, Brigitte; Navez, Malou; Rioult, Bruno; Tiberghien-Chatelain, Florence; Ganry, Hervé

    2011-09-01

    Postherpetic neuralgia (PHN) is a common, debilitating complication of herpes zoster that has a major impact on patients' quality of life. PHN prevalence increases with advancing age. One treatment option is the topical analgesic 5% lidocaine (lignocaine) medicated plaster (Versatis®), which has been proven to be efficacious and well tolerated in a number of randomized clinical studies. The aim of this analysis was to assess the use of the lidocaine medicated plaster under clinical practice conditions in a patient population whose previous PHN treatment with antidepressant and/or antiepileptic agents was inadequate or was not tolerated, or for whom such treatment was contraindicated or not recommended. This was a prospective, multicentre, non-interventional observation conducted in private and public health centres in France under a compassionate use programme (CUP). To obtain this new - and, at the time, unauthorized - PHN treatment alternative, physicians (in accordance with French guidelines) had to complete standardized case report forms for each patient before his/her inclusion in the CUP. As it was a CUP and therefore a non-interventional observation, returning documented information on follow-up visits to the medication provider was voluntary, and only a limited number of physicians returned completed forms. Documentation was, however, mandatory for adverse events (AEs) occurrence. Depending on the size of the painful skin area, up to three lidocaine plasters daily were applied for a maximum of 12 hours with plaster-free intervals of at least 12 hours. The study assessed changes in the prescription of concomitant PHN medication from the start of lidocaine plaster treatment to the last follow-up visit, both in terms of the sum of all concomitant PHN treatments and stratified by type of treatment: antiepileptic drugs, tricyclic antidepressants (TCAs), serotonin reuptake inhibitors (SRIs), classical analgesics (classified as step 1, 2 or 3 according to the WHO

  20. Treatment of postherpetic neuralgia with 5% lidocaine medicated plaster in elderly patients - subgroup analyses from three European clinical trials.

    Science.gov (United States)

    Sabatowski, Rainer; Bösl, Irmgard; König, Simone; Buchheister, Bettina; Meier, Torsten; Baron, Ralf

    2017-03-01

    To investigate short- and long-term effectiveness and safety of the 5% lidocaine medicated plaster in the treatment of postherpetic neuralgia (PHN) in elderly patients (≥70 years of age). Data from three European clinical trials was compared after stratification according to age (85% of elderly, >78% of younger patients) which was described by >51% as painful or extremely painful. Allodynia severity was markedly reduced in both groups during all three trials. Drug-related adverse events occurred in plaster provided pain relief and marked reductions in allodynia severity in elderly PHN patients with an excellent safety profile under short- and long-term treatment supporting the addition of the plaster to the treatment armamentarium for this age group. All analyzed study phases were open-label and lacking a placebo control group.

  1. [Implementing ambulatory prevention of thrombosis with low molecular weight heparin in plaster immobilization of the lower extremity].

    Science.gov (United States)

    Kock, H J; Schmit-Neuerburg, K P; Hanke, J; Terwort, A; Rudofsky, G; Hirche, H

    1994-12-01

    Plaster cast immobilisation following trauma is a major risk factor for the development of deep vein thrombosis. In our controlled, randomized and prospective study in patients with minor injuries the incidence of deep vein thrombosis was 4.3% in conservatively treated outpatients with plaster cast immobilisation of the leg (n = 163 control group without prophylaxis). By application of low molecular weight heparin once daily the number of deep vein thrombosis in the prophylaxis group (n = 176) was reduced to 0% (p = 0.006). No severe side effects of low molecular weight heparin were observed. Subcutaneous injections were self-applicated by 89% of males and 72% of females. We conclude that thromboprophylaxis with low molecular weight heparin once daily is effective to reduce the risk of deep vein thrombosis in outpatients with plaster cast immobilisation of the leg.

  2. The Terapeutic Effects of Electrical Acupuncture and Auricular-Plaster in 32 Cases of Chronic Fatigue Syndrome

    Institute of Scientific and Technical Information of China (English)

    Li Yuemei; Liu Hongping; Feng Shulan; Gong Dongfang

    2006-01-01

    Objective:To observe the therapeutic effects of electrical acupuncture and auricular-plaster therapy for chronic fatigue syndrome(CFS).Method:64 CFS patients were randomly divided into two groups.32 cases in the treatment group were treated by the electrical acupuncture and auricular-plaster therapy,and 32 cases in the control group with oral hydrocortisone.Results:The total effective rates were respectively 93.75% in the treatment group and 75.00% in the control group,with a statistically significant difference between the two groups(P<0.05).Conclusion:Electrical acupuncture and auricular-plaster therapy may show a better anti-fatigue effect than that of routine Western drugs.

  3. (AEDPH3)·(BtaH): a novel supramolecular plaster with formaldehyde adsorption and formaldehyde/ultraviolet ray-induced luminescence switching performance.

    Science.gov (United States)

    Chen, Shuo-ping; Hu, Le; Zhang, Yu-qin; Deng, Pu; Li, Cong; Chen, Xi; Yuan, Liang-jie

    2012-01-14

    A novel supramolecular plaster, (AEDPH(3))·(BtaH) (1), is synthesised and characterized. The supramolecular plaster is easy to synthesise and process, and displays good mechanical properties. It can adsorb and eliminate formaldehyde (HCHO) with high efficiency and exhibits very interesting HCHO/ultraviolet ray-induced luminescence switching.

  4. The effect of strong salinity and temperature gradients on transport processes and the formation of bathyal authigenic gypsum at a marine mud volcano

    Science.gov (United States)

    Haffert, L.; Haeckel, M.

    2012-04-01

    A thermodynamic activity model (Pitzer approach) applicable to extreme environmental pTS-conditions (up to 1000 bar, 200 ° C and 6 M NaCl) coupled to an extensive mineral database has been developed. The advantage of this code over existing ones, such as Phreeqc, Wateq, Minteq, is the additional integration of a comprehensive pressure correction, as well as the flexibility on the choice of input datasets, allowing fine-tuning of the model according the relevant pTS range. An example of the successful application of the model is the interpretation of near-surface pore water profiles from the Mercator mud volcano in the Gulf of Cadiz. These profiles are intriguing for two reasons. First, they are characterised by a strong salinity gradient in the upper 1-2 mbsf created by the mixing of upward advecting hypersaline (halite and gypsum saturated, S=360) mud volcano fluids and seawater (S=35) and, second, the pore water profiles encompass various types of authigenic gypsum (CaSO4·2H2O) and anhydrite (CaSO4) crystals, which usually form only in evaporitic environments. It was found that while high Ca and SO4 concentrations from dissolution of an underlying diapir provide gypsum saturated fluids, the occurrence of supersaturation and thus authigenic gypsum (or anhydrite) precipitation is only possible through the reduction of temperature. In addition to the strong temperature control, the salinity has an important impact on the resultant composition of the precipitating CaSO4 minerals. Increasing salinity significantly lowers the activity of water, thereby raising the gypsum-anhydrite transition zone from >1 km to about 500 m sediment depth at the MMV and during heat pulses (> 30 ° C) even to within a few metres below the seafloor. Another effect of the strong salinity gradient is its influence on the diffusive transport of solutes. When comparing the activity and concentration profiles of dissolved species at the Mercator mud volcano, it becomes obvious that here the

  5. Treatment of localized neuropathic pain of different etiologies with the 5% lidocaine medicated plaster - a case series.

    Science.gov (United States)

    Likar, Rudolf; Demschar, Susanne; Kager, Ingo; Neuwersch, Stefan; Pipam, Wolfgang; Sittl, Reinhard

    2015-01-01

    To assess the efficacy and safety of the topical 5% lidocaine medicated plaster in the treatment of localized neuropathic pain. This was a case series at an Austrian pain clinic, using retrospective analysis. Data of 27 patients treated for localized neuropathic pain with the 5% lidocaine medicated plaster were retrospectively analyzed. Assessment included changes in overall pain intensity, in intensity of different pain qualities, and of hyperalgesia and allodynia, and changes in sleep quality. Patients (17 female, ten male; mean age 53.4±11.4 years) presented mainly with dorsalgia (16 patients) or postoperative/posttraumatic pain (seven patients); one patient suffered from both. The mean overall pain intensity prior to treatment with lidocaine medicated plaster was 8.4±1.2 on the 11-point Likert scale. In the majority of cases, the lidocaine plaster was applied concomitantly with preexisting pain medication (81.5% of the patients). During the 6-month observation period, overall mean pain intensity was reduced by almost 5 points (4.98) to 3.5±2.6. Substantial reductions were also observed for neuralgiform pain (5 points from 7.9±2.6 at baseline) and burning pain (3 points from 5.2±4.1). Sleep quality improved from 4.6±2.6 at baseline to 5.5±1.8. Stratification by pain diagnosis showed marked improvements in overall pain intensity for patients with dorsalgia or postoperative/posttraumatic pain. The lidocaine plaster was well tolerated. Overall, topical treatment with the 5% lidocaine medicated plaster was associated with effective pain relief and was well tolerated.

  6. Treatment of localized neuropathic pain of different etiologies with the 5% lidocaine medicated plaster – a case series

    Science.gov (United States)

    Likar, Rudolf; Demschar, Susanne; Kager, Ingo; Neuwersch, Stefan; Pipam, Wolfgang; Sittl, Reinhard

    2015-01-01

    Objective To assess the efficacy and safety of the topical 5% lidocaine medicated plaster in the treatment of localized neuropathic pain. Study design This was a case series at an Austrian pain clinic, using retrospective analysis. Patients and methods Data of 27 patients treated for localized neuropathic pain with the 5% lidocaine medicated plaster were retrospectively analyzed. Assessment included changes in overall pain intensity, in intensity of different pain qualities, and of hyperalgesia and allodynia, and changes in sleep quality. Results Patients (17 female, ten male; mean age 53.4±11.4 years) presented mainly with dorsalgia (16 patients) or postoperative/posttraumatic pain (seven patients); one patient suffered from both. The mean overall pain intensity prior to treatment with lidocaine medicated plaster was 8.4±1.2 on the 11-point Likert scale. In the majority of cases, the lidocaine plaster was applied concomitantly with preexisting pain medication (81.5% of the patients). During the 6-month observation period, overall mean pain intensity was reduced by almost 5 points (4.98) to 3.5±2.6. Substantial reductions were also observed for neuralgiform pain (5 points from 7.9±2.6 at baseline) and burning pain (3 points from 5.2±4.1). Sleep quality improved from 4.6±2.6 at baseline to 5.5±1.8. Stratification by pain diagnosis showed marked improvements in overall pain intensity for patients with dorsalgia or postoperative/posttraumatic pain. The lidocaine plaster was well tolerated. Conclusion Overall, topical treatment with the 5% lidocaine medicated plaster was associated with effective pain relief and was well tolerated. PMID:25565882

  7. Efficacy and safety of the Betamethasone valerate 0.1% plaster in mild-to-moderate chronic plaque psoriasis: a randomized, parallel-group, active-controlled, phase III study.

    Science.gov (United States)

    Naldi, Luigi; Yawalkar, Nikhil; Kaszuba, Andrzej; Ortonne, Jean-Paul; Morelli, Paolo; Rovati, Stefano; Mautone, Giuseppe

    2011-06-01

    weeks' treatment with BMV plaster than with BMV cream (Cochran-Mantel-Haenszel test, p plaster group compared with the BMV cream group (analysis of covariance [ANCOVA] model, p = 0.017 at week 5). PGA scores were significantly lower after 3 and 5 weeks' treatment with BMV plaster (ANCOVA model, all p ≤ 0.016 vs BMV cream). Both treatments reduced itching and soreness to a similar degree, and the incidences of relapse during the follow-up period were comparable between treatment groups. There were no significant differences in AEs between treatment groups. BMV 0.1% plaster is more efficacious than BMV 0.1% cream in the treatment of patients with mild-to-moderate chronic plaque psoriasis in a clinical setting resembling daily clinical practice.

  8. Analysis of cubic and orthorhombic C3A hydration in presence of gypsum and lime

    KAUST Repository

    Kirchheim, A. P.

    2009-02-26

    Field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) have been used to study the microstructural changes and phase development that take place during the hydration of cubic (pure) and orthorhombic (Na-doped) tricalcium aluminate (C3A) and gypsum in the absence and presence of lime. The results demonstrate that important differences occur in the hydration of each C3A polymorph and gypsum when no lime is added; orthorhombic C3A reacts faster with gypsum than the cubic phase, forming longer ettringite needles; however, the presence of lime slows down the formation of ettringite in the orthorhombic sample. Additional rheometric tests showed the possible effects on the setting time in these cementitious mixes.

  9. The effect of magnesium on partial sulphate removal from mine water as gypsum.

    Science.gov (United States)

    Tolonen, Emma-Tuulia; Rämö, Jaakko; Lassi, Ulla

    2015-08-15

    The aim of this research was to investigate the effect of magnesium on the removal efficiency of sulphate as gypsum from mine water. The precipitation conditions were simulated with MINEQL + software and the simulation results were compared with the results from laboratory jar test experiments. Both the simulation and the laboratory results showed that magnesium in the mine water was maintaining sulphate in a soluble form as magnesium sulphate (MgSO4) at pH 9.6. Thus magnesium was preventing the removal of sulphate as gypsum (CaSO4·2H2O). However, change in the lime precipitation pH from 9.6 to 12.5 resulted in magnesium hydroxide (Mg(OH)2) precipitation and improved sulphate removal. Additionally, magnesium hydroxide could act as seed crystals for gypsum precipitation or co-precipitate sulphate further enhancing the removal of sulphate from mine water. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. STRUCTURE AND PROPERTIES OF COMPOSITE MATERIAL BASED ON GYPSUM BINDER AND CARBON NANOTUBES

    Directory of Open Access Journals (Sweden)

    CHUMAK Anastasia Gennadievna

    2013-04-01

    Full Text Available The aim of this work is to carry out a number of studies in the area of nanomodi­fication of gypsum binder matrix and to investigate the influence of multilayer carbon nanotubes on the structure, physical and mechanical properties of obtained compos­ites. The study of the gypsum binders structure formation mechanisms with the use of nanoadditives makes it possible to control the production processes of gypsum materi­als and articles with the given set of properties. The main tasks of the binder nanomodification are: even distribution of carbon nanostructures over the whole volume of material and provision of stability for the nanodimensional modifier during production process of the construction composite.

  11. Petroleum Sludge as gypsum replacement in cement plants: Its Impact on Cement Strength

    Science.gov (United States)

    Benlamoudi, Ali; Kadir, Aeslina Abdul; Khodja, Mohamed

    2017-08-01

    Due to high cost of cement manufacturing and the huge amount of resources exhaustion, companies are trying to incorporate alternative raw materials or by-products into cement production so as to produce alternative sustainable cement. Petroleum sludge is a dangerous waste that poses serious imparts on soil and groundwater. Given that this sludge contains a high percentage of anhydrite (CaSO4), which is the main component of gypsum (CaSO4.2H2O), it may play the same gypsum role in strength development. In this research, a total replacement of gypsum (100%) has been substituted by petroleum sludge in cement production and has led to an increase of 28.8% in UCS values after 28 curing days. Nevertheless, the burning of this waste has emitted a considerable amount of carbon monoxide (CO) gas that needs to be carefully considered prior to use petroleum sludge within cement plants.

  12. Compartmentalization of gypsum and halite associated with cyanobacteria in saline soil crusts.

    Science.gov (United States)

    Canfora, Loredana; Vendramin, Elisa; Vittori Antisari, Livia; Lo Papa, Giuseppe; Dazzi, Carmelo; Benedetti, Anna; Iavazzo, Pietro; Adamo, Paola; Jungblut, Anne D; Pinzari, Flavia

    2016-06-01

    The interface between biological and geochemical components in the surface crust of a saline soil was investigated using X-ray diffraction, and variable pressure scanning electron microscopy in combination with energy dispersive X-ray spectrometry. Mineral compounds such as halite and gypsum were identified crystallized around filaments of cyanobacteria. A total of 92 genera were identified from the bacterial community based on 16S gene pyrosequencing analysis. The occurrence of the gypsum crystals, their shapes and compartmentalization suggested that they separated NaCl from the immediate microenvironment of the cyanobacteria, and that some cyanobacteria and communities of sulfur bacteria may had a physical control over the distinctive halite and gypsum structures produced. This suggests that cyanobacteria might directly or indirectly promote the formation of a protective envelope made of calcium and sulfur-based compounds.

  13. Compartment syndrome developed due to the plaster cast :Three cases report

    Directory of Open Access Journals (Sweden)

    Pinar Doruk

    2013-08-01

    Full Text Available Compartment syndrome can occur as a result of the complication of the plaster cast applications ,which are frequently used for fracture stabilization. This syndrome occurs due to increased compartment volume or shrinking of compartment area because of edema, hemorrage or high pressure of tissues. All of these mechanisms causes arteriolar compression, resulting nerve and muscle ischemia. Intensive and continuous pain is common and limits the motions of the patient and increases with passive stretching of the involved muscles. Swelling of limb, change in skin color, peripheral vasculatory failure symptoms such as pallor,weak arterial pulsation and as a result of peripheral nerve damage, sensorimotor deficit can also be observed. Clinical evaluation, measure of pressure within the compartment, and electroneuromyography (ENMG can be used for the diagnosis. In addition to treatment of to the treatment of etiology and pain, further treatment options such as fasciotomy, physiotherapy modalities, tendon transfers, can be performed. In this case report, we will discuss three patients with nerve lesions as a result of the compartment syndrome that developed due to the plaster casting of bone fractures. [Cukurova Med J 2013; 38(4.000: 774-778

  14. LCA of Recycling Options for Gypsum from Construction and Demolition Waste

    DEFF Research Database (Denmark)

    Butera, Stefania; Møller, Jacob; Christensen, Thomas Højlund

    2011-01-01

    Large amounts of gypsum waste are annually produced from the construction and demolition sector. Its landfilling is becoming more and more expensive due to stricter EU regulations, while its recycling together with the rest of construction and demolition waste might be hampered due to technical...... restrictions; source separation, however, makes gypsum waste recycling feasible. Different alternatives for recycling exist, but their overall environmental impacts have never been quantified and compared in details. This study investigates from a life cycle perspective the environmental impacts of two...

  15. Gypsum addition to soils contaminated by red mud: implications for aluminium, arsenic, molybdenum and vanadium solubility.

    Science.gov (United States)

    Lehoux, Alizée P; Lockwood, Cindy L; Mayes, William M; Stewart, Douglas I; Mortimer, Robert J G; Gruiz, Katalin; Burke, Ian T

    2013-10-01

    Red mud is highly alkaline (pH 13), saline and can contain elevated concentrations of several potentially toxic elements (e.g. Al, As, Mo and V). Release of up to 1 million m(3) of bauxite residue (red mud) suspension from the Ajka repository, western Hungary, caused large-scale contamination of downstream rivers and floodplains. There is now concern about the potential leaching of toxic metal(loid)s from the red mud as some have enhanced solubility at high pH. This study investigated the impact of red mud addition to three different Hungarian soils with respect to trace element solubility and soil geochemistry. The effectiveness of gypsum amendment for the rehabilitation of red mud-contaminated soils was also examined. Red mud addition to soils caused a pH increase, proportional to red mud addition, of up to 4 pH units (e.g. pH 7 → 11). Increasing red mud addition also led to significant increases in salinity, dissolved organic carbon and aqueous trace element concentrations. However, the response was highly soil specific and one of the soils tested buffered pH to around pH 8.5 even with the highest red mud loading tested (33 % w/w); experiments using this soil also had much lower aqueous Al, As and V concentrations. Gypsum addition to soil/red mud mixtures, even at relatively low concentrations (1 % w/w), was sufficient to buffer experimental pH to 7.5-8.5. This effect was attributed to the reaction of Ca(2+) supplied by the gypsum with OH(-) and carbonate from the red mud to precipitate calcite. The lowered pH enhanced trace element sorption and largely inhibited the release of Al, As and V. Mo concentrations, however, were largely unaffected by gypsum induced pH buffering due to the greater solubility of Mo (as molybdate) at circumneutral pH. Gypsum addition also leads to significantly higher porewater salinities, and column experiments demonstrated that this increase in total dissolved solids persisted even after 25 pore volume replacements. Gypsum

  16. Study on the Possibility of Using Vine Stalk Waste ( Vitis Vinifera) for Producing Gypsum Particleboards

    Science.gov (United States)

    Rangavar, H.; Khosro, S. Kh.; Payan, M. H.; Soltani, A.

    2014-09-01

    The objective of this study was the production of gypsum particleboards with vine stalk waste and the investigation of some physical and mechanical properties of the boards. For this purpose, boards were made from gypsum, oven-dried mass of vine stalk waste, and the white portland cement in various ratios. The thickness swelling and water absorption after 2 and 24 hours of immersion in water, the modulus of rupture, the modulus of elasticity, and the internal bond strength of the boards were determined according to the European Norms standard. The results show that, by selecting proper ratios between the constituents, particleboards with good physicomechanical properties can be produced.

  17. Building on previous OSL dating techniques for gypsum: a case study from Salt Basin playa, New Mexico and Texas

    Science.gov (United States)

    Mahan, Shannon; Kay, John

    2012-01-01

    The long term stability and reliability of the luminescence signal for gypsum has not been well documented or systematically measured until just recently. A review of the current literature for luminescence dating of gypsum is compiled here along with original efforts at dating an intact and in-situ bed of selenite gypsum at Salt Basin Playa, New Mexico and Texas. This effort differs from other documented luminescence dating efforts because the gypsum is not powdery or redistributed from its original growth patterns within the playa basin but is instead of a crystalline form. Sixteen ages from eight cores were ultimately produced with seven of the ages coming from rare detrital quartz encased in or with the gypsum crystals while the remaining ages are from the crystalline gypsum. As far as can be ascertained, the quartz was measured separately from the gypsum and no contaminants were noted in any of the aliquots. Some basic and preliminary tests of signal stability were measured and found to be mitigated by lessening of pre-heat protocols. Ages ranged from 8 ka to 10 ka in the shallow cores and 16 ka to 22 ka in the deeper cores. These ages will be useful in determining rates of gypsum growth within a sequence of evaporates which, in turn, will help to better document historic rates of evaporation and thus estimate, with more precision, the corresponding annual evaporation rates.

  18. Evaluation of Synthetic Gypsum Recovered via Wet Flue-Gas Desulfurization from Electric Power Plants for Use in Foundries

    Directory of Open Access Journals (Sweden)

    R. Biernacki

    2012-09-01

    Full Text Available This article investigates possible use of waste gypsum (synthetic, recovered via flue-gas desulfurization from coal-fired electric powerplants, in foundries. Energy sector, which in Eastern Europe is mostly composed from coal-fired electric power plants, is one of the largestproducers of sulfur dioxide (SO2.In order to protect the environment and reduce the amount of pollution flue-gas desulfurization (FGD is used to remove SO2 fromexhaust flue gases of fossil-fuel power plants. As a result of this process gypsum waste is produced that can be used in practicalapplications.Strength and permeability tests have been made and also in-depth analysis of energy consumption of production process to investigateways of preparing the synthetic gypsum for casting moulds application. This paper also assesses the chemical composition, strength andpermeability of moulds made with synthetic gypsum, in comparison with moulds made with traditional GoldStar XL gypsum and withceramic molds. Moreover examination of structure of synthetic gypsum, the investigations on derivatograph and calculations of energyconsumption during production process of synthetic gypsum in wet flue-gas desulfurization were made.After analysis of gathered data it’s possible to conclude that synthetic gypsum can be used as a material for casting mould. There is nosignificant decrease in key properties, and on the other hand there is many additional benefits including low energy consumption,decreased cost, and decreased environmental impact.

  19. Sulfate specifications as a constraint to gypsum addition to cement and possible replacement of gypsum as an additive. Quarterly technical progress report, June-August 1979

    Energy Technology Data Exchange (ETDEWEB)

    Kantro, D.L.

    1979-10-01

    Potential alternatives to gypsum for controlling set in commercial cement, additives to deter sulfate-induced expansion, and the influence of clinker manufacture on expansion potential in cements were studied. If limitations on sulfate content were less restrictive, it would be possible to use kiln fuels with higher sulfur contents, and to employ energy efficient preheater kiln technology without risk of exceeding sulfate specifications. (FS)

  20. Stabilization of FGD gypsum for its disposal in landfills using amorphous aluminium oxide as a fluoride retention additive.

    Science.gov (United States)

    Alvarez-Ayuso, E; Querol, X

    2007-09-01

    The applicability of amorphous aluminium oxide as a fluoride retention additive to flue gas desulphurisation (FGD) gypsum was studied as a way of stabilizing this by-product for its disposal in landfills. Using a batch method the sorption behaviour of amorphous aluminium oxide was evaluated at the pH (about 6.5) and background electrolyte conditions (high chloride and sulphate concentrations) found in FGD gypsum leachates. It was found that fluoride sorption on amorphous aluminium oxide was a very fast process with equilibrium attained within the first half an hour of interaction. The sorption process was well described by the Langmuir model, offering a maximum fluoride sorption capacity of 61.7 mg g(-1). Fluoride sorption was unaffected by chloride co-existing ions, while slightly decreased (about 20%) by competing sulphate ions. The use of amorphous aluminium oxide in the stabilization of FGD gypsum proved to greatly decreased its fluoride leachable content (in the range 5-75% for amorphous aluminium oxide doses of 0.1-2%, as determined by the European standard EN 12457-4 [EN-12457-4 Characterization of waste-leaching-compliance test for leaching of granular waste materials and sludges-Part 4: one stage batch test at a liquid to solid ratio of 10 l/kg for materials with particle size below 10mm (without or with size reduction)]), assuring the characterization of this by-product as a waste acceptable at landfills of non-hazardous wastes according to the Council Decision 2003/33/EC [Council Decision 2003/33/EC of 19 December 2002. Establishing criteria and procedures for the acceptance of waste at landfills pursuant to Article 16 of and Annex II to Directive 1999/31/EC] on landfill of wastes. Furthermore, as derived from column leaching studies, the proposed stabilization system proved to be highly effective in simulated conditions of disposal, displaying a fluoride leaching reduction value about 81% for an amorphous aluminium oxide added amount of 2%.

  1. Plaster Casts after Antique Sculpture: Their Role in the Elevation of Public Taste and in American Art Instruction.

    Science.gov (United States)

    McNutt, James K.

    1990-01-01

    Examines the social, ideological, and cultural forces in colonial United States when plaster casts of Grecian and Roman sculpture were introduced. Describes how they were used in U.S. public schools and art museums to transmit the cultural heritage at the end of the nineteenth century. (KM)

  2. [Clinical research of post-stroke motor aphasia treated with acupoint application of jieyu plaster combined with acupuncture].

    Science.gov (United States)

    Fei, Aihua; Cai, Shengchao; Xu, Bin

    2015-11-01

    To compare the difference in clinical efficacy on post-stroke motor aphasia among the combined therapy of acupoint application of jieyu plaster and acupuncture, simple acupuncture and simple acupoint application of jieyu plaster. Eighty-six patients of post-stroke motor aphasia were randomized into an acupuncture group (28 cases) , an acupoint application gruop (29 cases) and the combined therapy group (29 cases). In the acupuncture group, acupuncture was applied at the Speech No. 1 area and three-tongue needling points, once a day, 6 times a week. In the acupoint application group, jieyue plaster was applied to Yongquan (KI 1) and Laogong (PC 8), once a day, and the bilateral acupoints were selected alternatively. In the combined therapy group, the therapeutic methods of the first two groups were used in combination. The treatment lasted for 4 weeks in the three groups. The speech function score was observed and compared before and after treatment in the three groups and the efficacy was compared among the three groups. The total effective rate was 86.2% (25/29) in the combined therapy group, which was better than 67.9% (19/28) in the acupuncture group and 69.0% (20/29) in the acupoint application group (both P plaster and acupuncture apparently improves the speech function in the treatment of post-stroke motor aphasia and the efficacy is better than that of simple acupuncture or simple acupoint application.

  3. Comparison of the moulding ability of Plaster of Paris and polyester cast material in the healthy adult forearm.

    Science.gov (United States)

    Bullen, Michael; Kinealy, John; Blanchard, Romane; Rodda, Christine; Pivonka, Peter

    2017-08-16

    To quantify the moulding ability of Plaster of Paris and polyester cast materials as assessed by the novel use of peripheral quantitative computed tomography. A prospective crossover study was performed in 25 healthy volunteers aged 18-65 years. Participants' non-dominant wrist was immobilized using a synthetic polyester cast followed by a Plaster of Paris cast with three point moulding to simulate reduction of a dorsally angulated distal radius fracture. The novel use of peripheral quantitative computed tomography was used to measure the closeness of fit of each cast on an axial tomographic slice. Plaster of Paris casts were able to achieve a closer mould than polyester when measured between the bone and the cast (p=0.002), as well as between the skin and the cast (p=0.001). There was no difference when stratified on BMI. Using pQCT assessment, a closely moulded fit was able to be more consistently achieved when using Plaster of Paris when compared to polyester casts of the distal radius. III. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Fifty Cases of Child Restless Syndrome Treated with the Integrated Method of Chinese Herbal Drugs and Auricular-Plaster Therapy

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Fifty cases of child restless syndrome were treated with oral administration of Chinese traditional herbal drugs plus auricular-plaster therapy from December 1998 to November 2001, and another 47 cases were treated with oral administration of methylphenidate as controls. The result is reported as follows.

  5. Karst-on-a-chip: microfluidic studies of dissolution of a gypsum fracture

    Science.gov (United States)

    Szymczak, Piotr; Dutka, Filip; Osselin, Florian

    2017-04-01

    Dissolution of fractured and porous media introduces a positive feedback between fluid transport and chemical reactions at mineral surfaces leading to self-focusing of the flow in pronounced wormhole-like channels [1,2]. We study the flow-induced dissolution in a simple microfluidic setup, with a gypsum block inserted in between two polycarbonate plates, which is the simplest model of a fracture [3]. This gives us a unique opportunity to observe the evolution of the dissolution patterns in-situ and in real-time. By changing the flow rate and the aperture of the fracture we can scan a relatively wide range of Peclet and Damkohler numbers, characterizing the relative magnitude of advection, diffusion and reaction in the system. Additionally, as the aperture is increased, a transition is observed between the fractal and regular dissolution patterns. For small gaps, the patterns are ramified fractals. For larger gaps, the dissolution fingers are found to have regular forms of two different kinds: either linear (for high flow rates) or parabolic (for lower flow rates). The experiments are supplemented with numerical simulations and analytical modeling which allow for a better understanding of evolving flow patterns. In particular, we find the shapes and propagation velocities of dominant fingers for different widths of the system, flow rates and reaction rates. Finally, we comment on the link between the experimentally observed patterns and the natural karst systems - both cave conduits and epikarst solution pipes. [1] Hoefner, M. L. and Fogler, H. S. Pore evolution and channel formation during flow and reaction in porous media. AIChE J. 34, 45-54, 1988 [2] P. Szymczak, A. J. C. Ladd, Wormhole formation in dissolving fractures, J. Geophys. Res., 114, B06203, 2009 [3] F. Osselin, P. Kondratiuk, A Budek, O. Cybulski, P. Garstecki, P. Szymczak Microfluidic observation of the onset of reactive infiltration instability in an analog fracture, Geophys. Res. Lett., 43, 6907

  6. Stable carbon and oxygen isotope investigation in historical lime mortar and plaster - Results from field and experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Kosednar-Legenstein, B. [Institute of Applied Geosciences, Graz University of Technology, Rechbauerstrasse 12, A-8010 Graz (Austria); Dietzel, M. [Institute of Applied Geosciences, Graz University of Technology, Rechbauerstrasse 12, A-8010 Graz (Austria)], E-mail: martin.dietzel@tugraz.at; Leis, A. [Institute of Water Resources Management, Hydrogeology and Geophysics, Joanneum Research, Elisabethstrasse 16/II, A-8010 Graz (Austria); Stingl, K. [Institute of Applied Geosciences, Graz University of Technology, Rechbauerstrasse 12, A-8010 Graz (Austria)

    2008-08-15

    Lime mortar and plaster were sampled from Roman, medieval and early modern buildings in Styria. The historical lime mortar and plaster consist of calcite formed in the matrix during setting and various aggregates. The stable C and O isotopic composition of the calcite matrix was analyzed to get knowledge about the environmental conditions during calcite formation. The {delta}{sup 13}C{sub matrix} and {delta}{sup 18}O{sub matrix} values range from -31 to 0 per mille and -26 to -3 per mille (VPDB), respectively. Obviously, such a range of isotope values does not represent the local natural limestone assumed to be used for producing the mortar and plaster. In an ideal case, the calcite matrix in lime mortar and plaster is isotopically lighter in the exterior vs. the interior mortar layer according to the relationship {delta}{sup 18}O{sub matrix} = 0.61 . {delta}{sup 13}C{sub matrix} - 3.3 (VPDB). Calcite precipitation by uptake of gaseous CO{sub 2} into alkaline Ca(OH){sub 2} solutions shows a similar relationship, {delta}{sup 18}O{sub calcite} = 0.67 . {delta}{sup 13}C{sub calcite} - 6.4 (VPDB). Both relationships indicate that the {sup 13}C/{sup 12}C and {sup 18}O/{sup 16}O values of the calcite reflect the setting behaviour of the lime mortar and plaster. Initially, CO{sub 2} from the atmosphere is fixed as calcite, which is accompanied by kinetic isotope fractionation mostly due to the hydroxylation of CO{sub 2} ({delta}{sup 13}C{sub matrix} {approx} -25 per mille and {delta}{sup 18}O{sub matrix} {approx} -20 per mille ). As calcite formation continued the remaining gaseous CO{sub 2} is subsequently enriched in {sup 13}C and {sup 18}O causing later formed calcite to be isotopically heavier along the setting path in the matrix. Deviations from such an ideal isotopic behaviour may be due to the evolution of H{sub 2}O, e.g. evaporation, the source of CO{sub 2}, e.g. from biogenic origin, relicts of the natural limestone, and secondary effects, such as

  7. Treatment of localized neuropathic pain of different etiologies with the 5% lidocaine medicated plaster – a case series

    Directory of Open Access Journals (Sweden)

    Likar R

    2014-12-01

    Full Text Available Rudolf Likar,1 Susanne Demschar,1 Ingo Kager,1 Stefan Neuwersch,1 Wolfgang Pipam,1 Reinhard Sittl2 1Department of Anesthesiology and Intensive Care, Hospital Klagenfurt, Klagenfurt, Austria; 2Department of Anesthesiology, Interdisciplinary Pain Centre, University Hospital Erlangen, Erlangen, Germany Objective: To assess the efficacy and safety of the topical 5% lidocaine medicated plaster in the treatment of localized neuropathic pain. Study design: This was a case series at an Austrian pain clinic, using retrospective analysis. Patients and methods: Data of 27 patients treated for localized neuropathic pain with the 5% lidocaine medicated plaster were retrospectively analyzed. Assessment included changes in overall pain intensity, in intensity of different pain qualities, and of hyperalgesia and allodynia, and changes in sleep quality. Results: Patients (17 female, ten male; mean age 53.4±11.4 years presented mainly with dorsalgia (16 patients or postoperative/posttraumatic pain (seven patients; one patient suffered from both. The mean overall pain intensity prior to treatment with lidocaine medicated plaster was 8.4±1.2 on the 11-point Likert scale. In the majority of cases, the lidocaine plaster was applied concomitantly with preexisting pain medication (81.5% of the patients. During the 6-month observation period, overall mean pain intensity was reduced by almost 5 points (4.98 to 3.5±2.6. Substantial reductions were also observed for neuralgiform pain (5 points from 7.9±2.6 at baseline and burning pain (3 points from 5.2±4.1. Sleep quality improved from 4.6±2.6 at baseline to 5.5±1.8. Stratification by pain diagnosis showed marked improvements in overall pain intensity for patients with dorsalgia or postoperative/posttraumatic pain. The lidocaine plaster was well tolerated. Conclusion: Overall, topical treatment with the 5% lidocaine medicated plaster was associated with effective pain relief and was well tolerated. Keywords

  8. [Case-control study on the treatmentof the fifth metatarsal base fractures by cardboard compression pad versus short leg plaster].

    Science.gov (United States)

    Xu, Ying-peng; Xie, Li-min; Xu, Chao; Zhang, Yue; Li, Yu-bin; Qiao, Xin

    2014-10-01

    To compare the effect,safety,and advantage of flexible fixation with paperboard and pad versus short leg plaster in treating the fifth metatarsal base fracture,and establish the standard of diagnosis and treatment of the fifth metatarsal base fractures in flexible fixation with paperboard and pad. From June 2010 to March 2013,59 patients with the fifth metatarsal base fracture were treated with paperboard and pad fixation or short leg plaster. Patients were enrolled and divided into paperboard and pad treatment group (paperboard group) and short leg plaster treatment group (plaster group) randomly according to the random number table. In paperboard group,there were 29 cases including 9 males and 20 females with an average age of (51.79±11.40) years old; the average course of injury was (11.59±6.58) hours. In plaster group, there were 30 cases including 9 males and 21 females with an average age of (52.13+17.34) years old ;the average course of injury was (11.03±7.06) hours. According to whether the fracture line across the articular surface, in paperboard group there were 14 cases of type A,15 of type B; in plaster group,16 of type A, 14 of type B. According to the degree of dislocation,in paperboard group there were 16 cases of degree I ,13 of degree II ; in plaster group,20 were degree I ,10 were degree II. Fracture was restored according to the type in manual. Patients in paperboard group were treated with paperboard and pad, and patients in plaster group were treated with short leg plaster. Fracture was fixed for 4 to 6 weeks according to fracture healing. On the 2nd, 4th,6th, 8th week and 3rd, 6th month after fixation, patients were followed up, and the foot function score was used to evaluate the function of injured foot. X-ray of injured foot was taken on the 2nd, 4th, 6th and 8th week were used to assess fracture healing. All patients got complete follow-up. The X-ray result showed that all fracture reached at clinical healing on the 8th week after

  9. Hydrothermal synthesis of calcium sulfate whisker from flue gas desulfurization gypsum

    Institute of Scientific and Technical Information of China (English)

    Chengjun Liu; Qing Zhao; Yeguang Wang; Peiyang Shi; Maofa Jiang

    2016-01-01

    Plenty of flue gas desulfurization (FGD) gypsum generated from coal-fired power plants for sulfur dioxide se-questration caused many environmental issues. Preparing calcium sulfate whisker (CSW) from FGD gypsum by hydrothermal synthesis is considered to be a promising approach to solve this troublesome problem and uti-lize calcium sulfate in a high-value-added way. The effects of particle size of FGD gypsum, slurry concentration, and additives on CSW were investigated in this work. The results indicated that fine particle size of FGD gypsum and moderately high slurry concentration were beneficial for crystal nucleation and growth. Three additives of magnesium chloride, citric acid, and sodium dodecyl benzene sulfonate (SDBS) were employed in this study. It was found that mean length and aspect ratio of CSW were both decreased by the usage of magnesium chloride, while a small quantity of citric acid or SDBS could improve the CSW morphology. When multi-additives of citric acid-SDBS were employed, the mean length and aspect ratio increased more than 20%. Moreover, surface morphology of CSW went better, and the particle size and crystal shape became more uniform.

  10. Morphology and stability of aggregates of an Oxisol according to tillage system and gypsum application

    Directory of Open Access Journals (Sweden)

    Fábio Régis de Souza

    2012-12-01

    Full Text Available Morphological characterization and aggregate stability is an important factor in evaluating management systems. The aim of this paper is to evaluate the stability and morphology of the aggregates of a dystrophic Oxisol managed with no-tillage and conventional tillage with and without the residual action of gypsum. The experimental design was randomized blocks arranged in split-split plot, where the treatments were two soil management systems (plots with 0 and 2000 kg ha-1 of gypsum (subplots and five depths (0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20 and 0.20-0.30 m as the subsubplots, with four replications. The aggregate morphology was determined through images and later evaluated by the Quantporo software. Stability was determined by the wet method. The results showed that the no-tillage system, with or without gypsum residual effect, provided the aggregates with the largest geometric diameters. The combination of no-tillage system and the gypsum residual effect provided rougher aggregates.

  11. Responses to Environmental Stress in Plants Adapted to Mediterranean Gypsum Habitats

    Directory of Open Access Journals (Sweden)

    Josep V. LLINARES

    2015-03-01

    Full Text Available Gypsum areas are stressful environments inhabited by gypsophytes, plants that are exclusive for such habitats, and by plants that grow on gypsum but also on other soil types, the so-called gypsovags. To investigate possible differences between gypsovags and gypsophytes with respect to basic stress response mechanisms, two common osmolytes, glycine betaine and total soluble sugars, as well as monovalent (Na+ and K+ and bivalent (Ca2+ and Mg2+ cations, were quantified, under field conditions, in two Iberian endemic gypsophytes (Gypsophila struthium subsp. hispanica and Ononis tridentata and two common Mediterranean gypsovags (Rosmarinus officinalis and Helianthemum syriacum. Their spatial variation according to a topographic gradient and their temporal variation over a period of three successive seasons were correlated with climatic data and soil characteristics. This analysis confirmed that water stress is the main environmental stress factor in gypsum habitats, whereas the percentage of gypsum in the soil does not seem to play any relevant role in the activation of stress responses in plants. Glycine betaine may contribute to stress tolerance in the gypsophytes, but not in the gypsovags, according to the close correlation found between the level of this osmolyte and the gypsophily of the investigated taxa. Cation contents in the plants did not correlate with those present in the soil, but the gypsophytes have higher levels of Ca2+ and Mg2+ than the gypsovags, under all environmental conditions, which may represent an adaptation mechanism to their specific habitat.

  12. Palaeoclimatic significance of gypsum pseudomorphs in the inner shelf sediments off Machalipatnam bay

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, V.P.

    Pseudo-gypsum crystals have been found in the coarse fraction of the sediments from the inner continental shelf off Machilipatnam Bay. They range in size from 3 to 7 mm are elongate and lenticular in shape. Bassanite and calcite are pseudomorphs...

  13. Composting and gypsum amendment of broiler litter to reduce nutrient leaching loss

    Science.gov (United States)

    Relative to fresh broiler litter, little is known about the dynamics of composted litter derived-nutrient in the ecosystem. In this study, the potential leaching losses of nutrients from compost relative to fresh broiler litter along with flue gas desulfurization (FGD gypsum), as a nutrient immobil...

  14. Study of Fresh and Hardening Process Properties of Gypsum with Three Different PCM Inclusion Methods

    Directory of Open Access Journals (Sweden)

    Susana Serrano

    2015-09-01

    Full Text Available Gypsum has two important states (fresh and hardened states, and the addition of phase change materials (PCM can vary the properties of the material. Many authors have extensively studied properties in the hardened state; however, the variation of fresh state properties due to the addition of Micronal® DS 5001 X PCM into gypsum has been the object of few investigations. Properties in fresh state define the workability, setting time, adherence and shrinkage, and, therefore the possibility of implementing the material in building walls. The aim of the study is to analyze, compare and evaluate the variability of fresh state properties after the inclusion of 10% PCM. PCM are added into a common gypsum matrix by three different methods: adding microencapsulated PCM, making a suspension of PCM/water, and incorporating PCM through a vacuum impregnation method. Results demonstrate that the inclusion of PCM change completely the water required by the gypsum to achieve good workability, especially the formulation containing Micronal® DS 5001 X: the water required is higher, the retraction is lower (50% less due to the organic nature of the PCM with high elasticity and, the adherence is reduced (up to 45% due to the difference between the porosity of the different surfaces as well as the surface tension difference.

  15. Investigation of Parameters Affecting Gypsum Dewatering Properties in a Wet Flue Gas Desulphurization Pilot Plant

    DEFF Research Database (Denmark)

    Hansen, Brian Brun; Kiil, Søren

    2012-01-01

    Wet flue gas desulphurization (FGD) plants with forced oxidation, installed at coal and oil fired power plants for removal of SO2(g), must produce gypsum of high quality. However, quality issues such as an excessive moisture content, due to poor gypsum dewatering properties, may occur from time...... to time. In this work, the particle size distribution, morphology, and filtration rate of wet FGD gypsum formed in a pilot-scale experimental setup, operated in forced oxidation mode, have been studied. The influence of holding tank residence time (10–408 h), solids content (30–169 g/L), and the presence...... of impurities (0.002 M Al2F6; 50 g quartz/L; 0.02 M Al3+, and 0.040 M Mg2+) were investigated. In addition, slurry from a full-scale wet FGD plant, experiencing formation of flat shaped crystals and poor gypsum dewatering properties, was transferred to the pilot plant to test if the plant would now start...

  16. Crack Coalescence in Molded Gypsum and Carrara Marble: Part 1. Macroscopic Observations and Interpretation

    Science.gov (United States)

    Wong, L. N. Y.; Einstein, H. H.

    2009-06-01

    Cracking and coalescence behavior has been studied experimentally with prismatic laboratory-molded gypsum and Carrara marble specimens containing two parallel pre-existing open flaws. This was done at both the macroscopic and the microscopic scales, and the results are presented in two separate papers. This paper (the first of two) summarizes the macroscopic experimental results and investigates the influence of the different flaw geometries and material, on the cracking processes. In the companion paper (also in this issue), most of the macroscopic deformation and cracking processes shown in this present paper will be related to the underlying microscopic changes. In the present study, a high speed video system was used, which allowed us to precisely observe the cracking mechanisms. Nine crack coalescence categories with different crack types and trajectories were identified. The flaw inclination angle ( β), the ligament length ( L), that is, intact rock length between the flaws, and the bridging angle ( α), that is, the inclination of a line linking up the inner flaw tips, between two flaws, had different effects on the coalescence patterns. One of the pronounced differences observed between marble and gypsum during the compression loading test was the development of macroscopic white patches prior to the initiation of macroscopic cracks in marble, but not in gypsum. Comparing the cracking and coalescence behaviors in the two tested materials, tensile cracking generally occurred more often in marble than in gypsum for the same flaw pair geometries.

  17. The Thermal Damage Properties of Mudstone, Gypsum and Rock Salt from Yingcheng, Hubei, China

    Directory of Open Access Journals (Sweden)

    Jie Chen

    2015-03-01

    Full Text Available The impacts of temperature on the surface thermal damage of rock salt, gypsum and mudstone from the Yingcheng salt mine, China were investigated by the surface crack growth and propagation tests at different temperatures. We found that: (a high temperature could strengthen the rock salt molecular thermal motion and weaken the cohesion among the rock salt grains, so that the grain boundaries were more prone to slip and thus develop into cracks; (b high temperature could make the water molecules evaporate from rock specimens, which should change the physical properties of gypsum and mudstone; and (c high temperature had a significant effect on the interface between rock salt and gypsum and mudstone, therefore it should be easy to produce cracks with white or light yellow cumulate powder here. The surface crack growth and propagation of the rock salt, gypsum and mudstone have a positive correlation with the temperature by stereo microscope and the method of binary images, which could observe the surface thermal damage properties. Finally, the fractal dimension of the rock salt surface cracks was calculated based on fractal theory, and the evolution of the surface thermal damage was found from 50 to 260 °C.

  18. 40 CFR 436.50 - Applicability; description of the gypsum subcategory.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the gypsum subcategory. 436.50 Section 436.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS MINERAL MINING AND PROCESSING POINT SOURCE CATEGORY...

  19. Decreasing phosphorus loss in tile-drained landscapes using flue gas desulfurization gypsum

    Science.gov (United States)

    Elevated phosphorus (P) loading from agricultural non-point source pollution continues to impair inland waterbodies throughout the world. The application of flue gas desulfurization (FGD) gypsum to agricultural fields has been suggested to decrease P loading because of its high calcium content and P...

  20. Assessment of Mercury in Soils, Crops, Earthworms, and Water when Soil is Treated with Gypsum

    Science.gov (United States)

    Flue gas desulfurization (FGD) gypsum from fossil fuel combustion has many potential uses in agriculture, but there is concern about the potential environmental effects of its elevated mercury (Hg) concentration. The wet limestone scrubbing process that removes sulfur from flue gas (and produces gyp...

  1. Clinical Observations on the Treatment of Migraine by Acupuncture plus Auricular Plaster Therapy

    Institute of Scientific and Technical Information of China (English)

    孙培华

    2007-01-01

    目的:探讨针刺配合耳压辨证治疗偏头痛的临床疗效.方法:将150例偏头痛患者随机分为观察组(n=90)和对照组(n=60).观察组患者采用针刺配合耳压辨证治疗,对照组患者采用口服西比灵治疗,并将两组的治疗效果进行对比观察.结果:观察组总有效率为94.4%,好于对照组(73.3%),观察组痊愈率为87.8%,高于对照组(55.0%).两组差异有非常显著意义(P<0.01).结论:观察组疗效明显优于对照组,运用针刺配合耳压辨证治疗偏头痛,能获得良好的临床疗效.%Objective: To investigate the clinical efficacy of acupuncture plus auricular plaster therapy for treating migraine. Methods: One hundred and fifty migraine patients were randomly allocated to an observation group (n=90) and a control group (n=60). The observation group were treated by acupuncture plus auricular plaster therapy based on syndrome differentiation and the control group, by oral administration of Flunarizine. The curative effects were compared between the two groups. Results: The total efficacy rate was 94.4% in the observation group and higher than in the control group (73.3%). The recovery rate was 87.8% in the observation group and higher than in the control group (55.0%). There were significant differences between the two groups (both P<0.01). The curative effect was significantly better in the observation group than in the control group. Conclusion: Clinically, acupuncture plus auricular plaster therapy based on syndrome differentiation has a good effect on migraine.

  2. Pregabalin, the lidocaine plaster and duloxetine in patients with refractory neuropathic pain: a systematic review

    Directory of Open Access Journals (Sweden)

    Budhia Sangeeta

    2010-11-01

    Full Text Available Abstract Background Patients frequently fail to receive adequate pain relief from, or are intolerant of, first-line therapies prescribed for neuropathic pain (NeP. This refractory chronic pain causes psychological distress and impacts patient quality of life. Published literature for treatment in refractory patients is sparse and often published as conference abstracts only. The aim of this study was to identify published data for three pharmacological treatments: pregabalin, lidocaine plaster, and duloxetine, which are typically used at 2nd line or later in UK patients with neuropathic pain. Methods A systematic review of the literature databases MEDLINE, EMBASE and CCTR was carried out and supplemented with extensive conference and grey literature searching. Studies of any design (except single patient case studies that enrolled adult patients with refractory NeP were included in the review and qualitatively assessed. Results Seventeen studies were included in the review: nine of pregabalin, seven of the lidocaine plaster, and one of duloxetine. No head-to-head studies of these treatments were identified. Only six studies included treatments within UK licensed indications and dose ranges. Reported efficacy outcomes were not consistent between studies. Pain scores were most commonly assessed in studies including pregabalin; trials of pregabalin and the lidocaine plaster reported the proportion of responders. Significant improvements in the total, sensory and affective scores of the Short-form McGill Pain Questionnaire, and in function interference, sleep interference and pain associated distress, were associated with pregabalin treatment; limited or no quality of life data were available for the other two interventions. Limitations to the review are the small number of included studies, which are generally small, of poor quality and heterogeneous in patient population and study design. Conclusions Little evidence is available relevant to the

  3. Functional treatment versus plaster for simple elbow dislocations (FuncSiE: a randomized trial

    Directory of Open Access Journals (Sweden)

    Verleisdonk Egbert JMM

    2010-11-01

    Full Text Available Abstract Background Elbow dislocations can be classified as simple or complex. Simple dislocations are characterized by the absence of fractures, while complex dislocations are associated with fractures. After reduction of a simple dislocation, treatment options include immobilization in a static plaster for different periods of time or so-called functional treatment. Functional treatment is characterized by early active motion within the limits of pain with or without the use of a sling or hinged brace. Theoretically, functional treatment should prevent stiffness without introducing increased joint instability. The primary aim of this randomized controlled trial is to compare early functional treatment versus plaster immobilization following simple dislocations of the elbow. Methods/Design The design of the study will be a multicenter randomized controlled trial of 100 patients who have sustained a simple elbow dislocation. After reduction of the dislocation, patients are randomized between a pressure bandage for 5-7 days and early functional treatment or a plaster in 90 degrees flexion, neutral position for pro-supination for a period of three weeks. In the functional group, treatment is started with early active motion within the limits of pain. Function, pain, and radiographic recovery will be evaluated at regular intervals over the subsequent 12 months. The primary outcome measure is the Quick Disabilities of the Arm, Shoulder, and Hand score. The secondary outcome measures are the Mayo Elbow Performance Index, Oxford elbow score, pain level at both sides, range of motion of the elbow joint at both sides, rate of secondary interventions and complication rates in both groups (secondary dislocation, instability, relaxation, health-related quality of life (Short-Form 36 and EuroQol-5D, radiographic appearance of the elbow joint (degenerative changes and heterotopic ossifications, costs, and cost-effectiveness. Discussion The successful

  4. The Americleft Project: Plaster Dental Casts Versus Digital Images for GOSLON Yardstick Ratings When Used in Intercenter Comparisons.

    Science.gov (United States)

    Long, Ross E; Daskalogiannakis, John; Mercado, Ana M; Hathaway, Ronald R; Fessler, Jennifer; Russell, Kathleen A

    2017-07-01

    The purpose of this investigation was to determine reliability and validity of GOSLON Yardstick ratings using plaster casts versus photo galleries of digital images in actual intercenter comparisons. The dental arch relationships of 112 patients with complete unilateral cleft lip and palate from 3 North American cleft/craniofacial centers were rated in 2 separate studies. In the first, plaster casts were used. For a later intercenter comparison, the same dental casts were scanned, digital bases added, and two-dimensional photographic galleries (6 views) were created for each set of casts. Three raters experienced with the GOSLON Yardstick carried out 2 separate ratings of the plaster casts in the first study, then of the photographic gallery of scanned digital images of the same casts in the second study. Inter- and intrarater reliabilities were calculated using the Weighted Kappa statistic. Average scores for each patient were calculated and compared between methods with correlation statistics and a Bland-Altman plot. Kruskal-Wallis test was used to compare results between centers using both media. Reliability using both methods was very good and comparable between methods. Mean weighted Kappas were: inter-rater = 0.815 (plaster) versus 0.891 (photo); and intrarater = 0.866 (plaster) versus 0.891 (photo). There was a highly significant correlation (r = 0.920). Mean difference between centers was 0.033 of a GOSLON category. The level of significance of the differences found between centers with both methods was identical, confirming the interchangeability of both media presentations.

  5. Investigation on the Permeability Evolution of Gypsum Interlayer Under High Temperature and Triaxial Pressure

    Science.gov (United States)

    Tao, Meng; Yechao, You; Jie, Chen; Yaoqing, Hu

    2017-08-01

    The permeability of the surrounding rock is a critical parameter for the designing and assessment of radioactive waste disposal repositories in the rock salt. Generally, in the locations that are chosen for radioactive waste storage, the bedded rock salt is a sedimentary rock that contains NaCl and Na2SO4. Most likely, there are also layers of gypsum ( {CaSO}_{ 4} \\cdot 2 {H}_{ 2} {O)} present in the salt deposit. Radioactive wastes emit a large amount of heat and hydrogen during the process of disposal, which may result in thermal damage of the surrounding rocks and cause a great change in their permeability and tightness. Therefore, it is necessary to investigate the permeability evolution of the gypsum interlayer under high temperature and high pressure in order to evaluate the tightness and security of the nuclear waste repositories in bedded rock salt. In this study, a self-designed rock triaxial testing system by which high temperature and pressure can be applied is used; the μCT225kVFCB micro-CT system is also employed to investigate the permeability and microstructure of gypsum specimens under a constant hydrostatic pressure of 25 MPa, an increasing temperature (ranging from 20 to 650 °C), and a variable inlet gas pressure (1, 2, 4, 6 MPa). The experimental results show: (a) the maximum permeability measured during the whole experiment is less than 10-17 m2, which indicates that the gypsum interlayer has low permeability under high temperature and pressure that meet the requirements for radioactive waste repository. (b) Under the same temperature, the permeability of the gypsum specimen decreases at the beginning and then increases as the pore pressure elevates. When the inlet gas pressure is between 0 and 2 MPa, the Klinkenberg effect is very pronounced. Then, as the pore pressure increases, the movement behavior of gas molecules gradually changes from free motion to forced directional motion. So the role of free movement of gas molecules gradually

  6. Can isotopic variations in structural water of gypsum reveal paleoclimatic changes?

    Science.gov (United States)

    Gatti, E.; Bustos, D.; Coleman, M. L.

    2015-12-01

    Water of crystallization in gypsum can be used as paleo-environmental proxy to study large scale climatic variability in arid areas. This is because changes in the isotopic composition of water of crystallization are due to isotopic variations in the mother brine from which the mineral precipitated, and the brine isotopic composition is linked to evaporation processes and humidity. This is particularly important when the salts are the only traces left of the original water, i.e. in modern arid areas. This study aims to prove that the 2-D/18-O compositions of the water of crystallization extracted from successive precipitates or even different growth zones of natural gypsum (CaSO4·H2O) can reconstruct the evaporation history and paleo-humidity of the source water basin. The method was tested in a laboratory experiment that evaporated CaSO4 brines under controlled temperature and humidity conditions. The brine was left to evaporate for five days at two different humidities (45 and 75 RH%); subsequently, brines and precipitated gypsum were sampled at 24 hour intervals. In this way we simulated zoned growth of gypsum. The samples were then analyzed for oxygen and hydrogen isotopic composition using a Thermo Scientific TC/EA with modified column, coupled to a MAT 253 Thermo Finnigan mass spectrometer at JPL. If preliminary results validate the novel hypothesis that changes in mineral composition can reveal details of paleo-environmental conditions the theory will be tested on natural gypsum collected from selected areas in White Sands National Monument, New Mexico. The study is currently ongoing but the full dataset will be presented at the conference.

  7. Using Gypsum Hydration Water to Quantitatively Estimate the Intensity of the Terminal Classic Drought in the Maya Lowlands

    Science.gov (United States)

    Gázquez, F.; Evans, N. P.; Bauska, T. K.; Hodell, D. A.

    2016-12-01

    Paleoclimate evidence suggests that drought coincided with the collapse of the lowland Classic Maya civilization between 800 and 1000 AD. However, attempts to quantitatively determine the magnitude of hydrologic change have met with mixed results. Several periods of gypsum deposition have been documented in Lake Chichancanab (Yucatan Peninsula, Mexico) sediment cores and interpreted as representing times of drought. Here we analyzed the triple oxygen (17O/16O, 18O/16O) and hydrogen (2H/1H) isotope ratios of the gypsum hydration water to obtain the δ18O, δD, 17O-excess, and d-excess of the lake water during the drought periods. By comparing these results to measurements made on the modern lake, rain and ground waters, we are able to better constrain the hydrological changes that occurred in the lake basin during the Terminal Classic Drought (TCD). During the TCD, the δ18O and δD of the lake water increased compared with modern values, whereas the 17O-excess, and d-excess decreased. The isotopic composition of lake water (δ17O, δ18O and δD, and derived d-excess and 17O-excess) is sensitive to changes in atmospheric relative humidity and temperature. We modeled the isotopic data and found the observed changes can be explained by a 10% reduction in relative humidity compared to modern conditions. This reduction in relative humidity was accompanied by a significant increase in evaporation over precipitation. Furthermore, we show that the driest period occurred during the early phase of the TCD (ca 770-870 AD) when the Classic Maya declined. Previous studies based on stalagmite δ18O records suggested that the greatest drought period occurred in the Postclassic Period (1020 and 1100 AD) and post-dated the collapse. Our findings from Lake Chichancanab suggest that the changes to the hydrological budget during the TCD were greater than those during the early Postclassic Period.

  8. A Photodegradation Study of Three Common Paint and Plaster Biocides under monochromatic UV Light

    DEFF Research Database (Denmark)

    Minelgaite, Greta; Vollertsen, Jes; Nielsen, Asbjørn Haaning

    2014-01-01

    Photodegradation of the three common paint-and-plaster biocides (carbendazim, diuron and terbutryn) was investigated at controlled laboratory conditions. Samples prepared in two types of water (demineralized water and pond water) were subjected to 254 nm monochromatic UV light. Light intensity (W m......-2) in the experimental chamber was measured by a fiber optic spectrometer. The observed decline in biocide concentration was related with the light energy, accumulated during the time of degradation (kJ m-2), and 1st order photodegradation rate constants (m2 kJ-1) were determined. The obtained...... results demonstrated that diuron and terbutryn were readily degradable at the tested conditions, while carbendazim remained stable throughout the 28 – 34 hours of the experiments. Photodegradation rate constants of diuron and terbutryn were found to be slightly higher in demineralized water (0.0183 – 0...

  9. Archaeomagnetic investigation of oriented pre-Columbian lime-plasters from Teotihuacan, Mesoamerica

    Science.gov (United States)

    Soler-Arechalde, A. M.; Sánchez, F.; Rodriguez, M.; Caballero-Miranda, C.; Goguitchaishvili, A.; Urrutia-Fucugauchi, J.; Manzanilla, L.; Tarling, D. H.

    2006-10-01

    Results of an archaeomagnetic study of two excavation field seasons at the Xalla and Teopancazco residential areas of the ancient Prehispanic city of Teotihuacan, Central Mexico are reported. One-hundred and fifty three oriented samples of lime-plasters from the two archaeological sites were collected for the study. NRM directions are reasonably well grouped. Alternating field demagnetization shows single or two-component magnetizations. Rock magnetic measurements point to fine-grained titanomagnetites with pseudo-single domain behaviour. Characteristic site mean directions from both sites are correlated to the available palaeosecular variation curve for Mesoamerica. The mean directions obtained from Xalla site point to average dates of 550 AD±25 years that matches with the documented `Big Fire' of Teotihuacan (AD 575). Two consecutive construction levels at Teopancazco were estimated as AD 250-350 and AD 350-425 respectively.

  10. Contaminant mobility and carbon sequestration downstream of the Ajka (Hungary) red mud spill: The effects of gypsum dosing.

    Science.gov (United States)

    Renforth, P; Mayes, W M; Jarvis, A P; Burke, I T; Manning, D A C; Gruiz, K

    2012-04-01

    A number of emergency pollution management measures were enacted after the accidental release of caustic bauxite processing residue that occurred in Ajka, western Hungary in October, 2010. These centred on acid and gypsum dosing to reduce pH and minimise mobility of oxyanion contaminants mobile at high pH. This study assessed the effectiveness of gypsum dosing on contaminant mobility and carbon sequestration through assessment of red mud and gypsum-affected fluvial sediments via elemental analysis and stable isotope analysis. There was a modest uptake of contaminants (notably As, Cr, and Mn) on secondary carbonate-dominated deposits in reaches subjected to gypsum dosing. C and O stable isotope ratios of carbonate precipitates formed as a result of gypsum dosing were used to quantify the importance of the neutralisation process in sequestering atmospheric carbon dioxide. This process was particularly pronounced at sites most affected by gypsum addition, where up to 36% of carbonate-C appears to be derived from atmospheric in-gassing of CO(2). The site is discussed as a large scale analogue for potential remedial approaches and carbon sequestration technologies that could be applied to red mud slurries and other hyperalkaline wastes. The results of this work have substantial implications for the aluminium production industry in which 3-4% of the direct CO(2) emissions may be offset by carbonate precipitation. Furthermore, carbonation by gypsum addition may be important for contaminant remediation, also providing a physical stabilisation strategy for the numerous historic stockpiles of red mud.

  11. Cancer mortality in towns in the vicinity of installations for the production of cement, lime, plaster, and magnesium oxide.

    Science.gov (United States)

    García-Pérez, Javier; López-Abente, Gonzalo; Castelló, Adela; González-Sánchez, Mario; Fernández-Navarro, Pablo

    2015-06-01

    Our objective was to investigate whether there might be excess cancer mortality in the vicinity of Spanish installations for the production of cement, lime, plaster, and magnesium oxide, according to different categories of industrial activity. An ecologic study was designed to examine municipal mortality due to 33 types of cancer (period 1997-2006) in Spain. Population exposure to pollution was estimated on the basis of distance from town to industrial facility. Using spatial Besag-York-Mollié regression models with integrated nested Laplace approximations for Bayesian inference, we assessed the relative risk of dying from cancer in a 5-km zone around installations, analyzed the effect of category of industrial activity according to the manufactured product, and conducted individual analyses within a 50-km radius of each installation. Excess all cancer mortality (relative risk, 95% credible interval) was detected in the vicinity of these installations as a whole (1.04, 1.01-1.07 in men; 1.03, 1.00-1.06 in women), and, principally, in the vicinity of cement installations (1.05, 1.01-1.09 in men). Special mention should be made of the results for tumors of colon-rectum in both sexes (1.07, 1.01-1.14 in men; 1.10, 1.03-1.16 in women), and pleura (1.71, 1.24-2.28), peritoneum (1.62, 1.15-2.20), gallbladder (1.21, 1.02-1.42), bladder (1.11, 1.03-1.20) and stomach (1.09, 1.00-1.18) in men in the vicinity of all such installations. Our results suggest an excess risk of dying from cancer, especially in colon-rectum, in towns near these industries.

  12. 30 CFR 57.22219 - Seals and stoppings (II-A mines).

    Science.gov (United States)

    2010-07-01

    ... brattice, shall be coated with at least one inch of construction plaster containing perlite and gypsum; at... plaster containing perlite and gypsum; at least one inch of expanded vermiculite, Portland cement...

  13. Cleaning plaster surfaces with agar-agar gels: evaluation of the technique

    Directory of Open Access Journals (Sweden)

    Sonia Tortajada Hernando

    2013-07-01

    Full Text Available Abstract: Cleaning plaster surfaces represent a challenge for conservators It should only be performed following fully tested methods that guarantee the conservation of such fragile material. The goal of this work is to establishing a suitable cleaning method for this type of artworks from the tested concentrations and time of applications, using agar gels on plaster supports. Morphological, porosity and weight variations have been studied. Confocal and stereomicroscopy have been used as analytical techniques, as well as the measurement of water vapor permeability and weight have been taken on the samples. La limpieza de superficies de yeso-escayola con geles de agar-agar: evaluación de la técnica Resumen: La limpieza segura y eficiente de las superficies de yeso constituye un reto y una responsabilidad para el conservador-restaurador, y debe llevarse a cabo siguiendo métodos testados que garanticen su correcta conservación. La intención de este trabajo es determinar, a partir de las concentraciones y tiempos de aplicación ensayados, cuáles serían los parámetros óptimos para la ejecución de una limpieza eficaz e inocua empleando geles de agar-agar sobre soportes de yeso. Se han comprobado las posibles variaciones morfológicas de la superficie, las variaciones de la porosidad y del peso, así como la presencia de residuos, para lo cual se ha empleado la microscopía confocal, microscopía binocular, la medida de la permeabilidad al vapor de agua y la medida del peso de las muestras.

  14. Selection of the temperature of casting the bronzes to plaster moulds

    Directory of Open Access Journals (Sweden)

    B. Pisarek

    2009-07-01

    Full Text Available The results of the investigations of the process of solidification of the bronze CuSn5Zn5Pb5-C (B555 and CuSn10-C (B10 in the hot plaster mould show in the work. For four temperatures of casting: 1200 ° C, 1180 ° C, 1160 ° C and 1140 ° C was conducted the investi-gation: the size of contraction cavity, the fulfillment of the mould cavity formative the casts of test slats about the thickness: 4 mm, 0,8 mm and 0,5 mm. It was conducted the investigation the processes sets in the arrangement the cast-mould and X-ray analysis phase XRD of compound coming into being in indirect layer created among mould and cast in the result of the thermal decomposition of the anhy-drite. It results that the temperature 1140 ° C is the optimum temperature of casting the bronze to hot plaster mould from carried out investiga-tions. The minimum thickness of the wall of the cast from the bronze B555 is 0.5 mm, and from the bronze B10 0.8 mm.The realization of casts about thinner walls is made difficult because of giving off formed gases in the result of the thermal decomposition of the anhydrite. The products of the decomposition of the anhydrite react with elements steps in the chemical composition of studied bronzes, create in the arrangement the cast-mould the indirect layer folded from: sulphites, sulphides, oxides and clean metals (Pb or their compounds, especially Sn and Sb.

  15. Formation mechanism of authigenic gypsum in marine methane hydrate settings: Evidence from the northern South China Sea

    Science.gov (United States)

    Lin, Qi; Wang, Jiasheng; Algeo, Thomas J.; Su, Pibo; Hu, Gaowei

    2016-09-01

    During the last decade, gypsum has been discovered widely in marine methane hydrate-bearing sediments. However, whether this gypsum is an in-situ authigenic precipitate remains controversial. The GMGS2 expedition carried out in 2013 by the Guangzhou Marine Geological Survey (GMGS) in the northern South China Sea provided an excellent opportunity for investigating the formation of authigenic minerals and, in particular, the relationship between gypsum and methane hydrate. In this contribution, we analyzed the morphology and sulfur isotope composition of gypsum and authigenic pyrite as well as the carbon and oxygen isotopic compositions of authigenic carbonate in a drillcore from Site GMGS2-08. These methane-derived carbonates have characteristic carbon and oxygen isotopic compositions (δ13C: -57.9‰ to -27.3‰ VPDB; δ18O: +1.0‰ to +3.8‰ VPDB) related to upward seepage of methane following dissociation of underlying methane hydrates since the Late Pleistocene. Our data suggest that gypsum in the sulfate-methane transition zone (SMTZ) of this core precipitated as in-situ authigenic mineral. Based on its sulfur isotopic composition, the gypsum sulfur is a mixture of sulfate derived from seawater and from partial oxidation of authigenic pyrite. Porewater Ca2+ ions for authigenic gypsum were likely generated from carbonate dissolution through acidification produced by oxidation of authigenic pyrite and ion exclusion during methane hydrate formation. This study thus links the formation mechanism of authigenic gypsum with the oxidation of authigenic pyrite and evolution of underlying methane hydrates. These findings suggest that authigenic gypsum may be a useful proxy for recognition of SMTZs and methane hydrate zones in modern and ancient marine methane hydrate geo-systems.

  16. Soil fertility, nutrition and yield of maize and barley with gypsum application on soil surface in no-till

    Directory of Open Access Journals (Sweden)

    Leandro Michalovicz

    2014-10-01

    Full Text Available Annual crop yield and nutrition have shown differentiated responses to modifications in soil chemical properties brought about by gypsum application. The aim of this study was to evaluate the effect of gypsum application rates on the chemical properties of a Latossolo Bruno (Clayey Oxisol, as well as on the nutrition and yield of a maize-barley succession under no-till. The experiment was set up in November 2009 in Guarapuava, Parana, Brazil, applying gypsum rates of 0.0, 1.5, 3.0, 4.5, and 6.0 Mg ha-1 to the soil surface upon sowing maize, with crop succession of barley. Gypsum application decreased the levels of Al3+ and Mg2+ in the 0.0-0.1 m layer and increased soil pH in the layers from 0.2-0.6 m depth. Gypsum application has increased the levels of Ca2+ in all soil layers up to 0.6 m, and the levels of S-SO4(2- up to 0.8 m. In both crops, the leaf concentrations of Ca and S were increased while Mg concentrations have decreased as a function of gypsum rates. There was also an effect of gypsum rates on grain yield, with a quadratic response of maize and a linear increase for barley. Yield increases were up to 11 and 12 % in relation to control for the maximum technical efficiency (MTE rates of 3.8 and 6.0 Mg ha-1 of gypsum, respectively. Gypsum application improved soil fertility in the profile, especially in the subsurface, as well as plant nutrition, increasing the yields of maize and barley.

  17. 水杨酸普鲁兰糖涂膜剂体内外透皮释放初步评价%Preliminary evaluation of the transdermal release of salicylic acid pullulan plaster in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    李海鹰; 杨文智; 王芳; 蒋元勋; 申世刚

    2013-01-01

    OBJECTIVE To prepare salicylic acid pullulan plaster (SAPP) and investigate its release in vitro and in vivo. METHODS An HPLC method was established for the determination of salicylic acid in receptor cell. The permeation rate and penetration mechanism of SAPP through rat skin in vitro were examined using the standing posture Franz's type diffusion cell. Another HPLC method was developed to determine the salicylic acid plasma concentration and then employed to study the phar-macokinetics of salicylic acid after using plaster in rabbits. RESULTS The permeation tests through excised rat skin demonstrated that the optimized salicylic acid controlled-release plaster exhibited Higuchi model. The salicylic acid plasma concentration with ultrasonic rose quickly and reached a peak (Cmax ,39 μg·mL-1) after 0. 5 h whereas a peak (Cmax,35 μg·mL-1) after 1 h without ultrasonic. The areas under plasma concentration curves (AUC) of salicylic acid using plaster with ultrasonic was also better than that without ultrasonic. CONCLUSION Pullulan could be a matrix of plaster. Salicylic acid in the plaster was delayed release. SAPP with ultrasonic administration showed a slightly increased AUC value. It was evident that the SAPP with ultrasonic exhibited good transdermal delivery properties. There was a high correlation between in vitro transdermal delivery and in vivo percutaneous absorption using SAPP,and the salicylic acid release in -vitro could predict its absorption in vivo.%目的:对自制水杨酸普鲁兰糖涂膜剂进行体内外透皮释放行为考察.方法:自制3批涂膜剂,采用HPLC法测定涂膜剂中水杨酸含量.选取昆明种小鼠鼠皮,用立式扩散池评价涂膜剂中水杨酸体外释放行为;选用新西兰兔背敷涂膜剂,测定兔体内水杨酸的药时曲线,并考察超声促透效果.结果:自制水杨酸普鲁兰糖涂膜剂体外释放缓慢,释放过程可用Higuchi方程模拟.兔体内药时曲线显示,水杨酸血药浓度1h

  18. Is external fixation a better way than plaster to supplement K-wires in non-comminuted distal radius fractures?

    Science.gov (United States)

    Athar, Sajjad M; Ashwood, Neil; Aerealis, George; Bain, Gregory I

    2017-09-05

    Distal radius fractures represent about one-sixth of all fractures. There is still no consensus on the treatment of this fracture. We have several issues to assess and address; one of them is the fixation method. We tried to compare the effectiveness of two methods of stabilisation of distal radial fracture. Comparison between the techniques of Kirschner wire (K-wire) fixation with plaster and K-wire fixation with external fixation (Ex-Fix) was undertaken to assess which treatment modality gives better results in patients with distal radius fracture Frykman VII and VIII with no metaphyseal comminution. Fifty-six patients were chosen randomly and then allocated to two different modalities of stabilisation randomly as well, they were followed up; three of them were lost to follow-up because of death and two moved away from the area. Fifty-one patients were randomised in two groups: 24 were treated with K-wire and spanning Ex-Fix supplementation and 27 were treated with K-wires and plaster. Patients were prospectively monitored following the operation with a minimum follow-up of 1 year. Measurement of range of motion was obtained after surgery. Visual Analogue Scale (VAS) scores for pain and satisfaction levels were also recorded. There was statistically significant difference in favour of the Ex-Fix patient group for pain (VAS, Ex-Fix group: mean 14.9; plaster group: mean 28.1) and satisfaction (Ex-Fix group: mean 89.7;plaster group: mean 76.3). Although one would expect that range of motion would be reduced in the Ex-Fix group, there were no statistically significant differences found, with the exception of supination where results were in favour of the Ex-Fix group (mean 54.4; plaster group: mean 45.2). In our study, xternal fixator (Ex-Fix) supplementation of K-wiring favoured patients with distal radius fracture, even though there was no metaphyseal comminution, and therefore is suggested in contrast to plaster supplementation. © Article author(s) (or their

  19. In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature

    Institute of Scientific and Technical Information of China (English)

    LIU Chuan-Jiang; ZHENG Hai-Fei

    2012-01-01

    An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC).The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa.With increasing temperature,the anhydrite (CaSO4) phase precipitates at 250 320℃ in the pressure range of 1.0 1.5 GPa,indicating that under a saturated water condition,both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite.A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) =0.0068T - 0.7126 (250℃≤T≤320℃).Anhydrite remained stable during rapid cooling of the sample chamber,showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.%An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 Mpa. With increasing temperature, the anhydrite (CaSO4) phase precipitates at 250-320℃ in the pressure range of 1.0-1.5 Gpa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(Gpa) = 0.0068T - 0.7126 (250℃≤T≤320℃). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is

  20. Rheological Behaviour and Microstructures of Natural Gypsum Experimentally Deformed in Simple Shear

    Science.gov (United States)

    Barberini, V.; Burlini, L.; Rutter, E. H.; Dapiaggi, M.

    2003-12-01

    Gypsum is an important mineral of evaporitic rocks. Evaporites, interlayered within sedimentary sequences, play an important role in localizing the deformation especially in thrust tectonics (Apennines, Zagros, Gulf of Mexico, etc.) since are generally weaker than the other rocks; in some cases the deformation is accompanied by seismicity as in the Northern Apennines extensional systems. In order to determine the rheological and microstructural evolution of gypsum with strain, a set of experiments was performed on natural gypsum samples from Volterra (Tuscany, Italy). Experimental deformation tests were performed at confining pressures up to 300 MPa, at temperatures up to 130° C and at strain rates ranging between 6x10-4 and 5x10-6 s-1. In order to reach high shear strain values, we deformed gypsum specimens using both the torsion technique in the Paterson apparatus at ETH Zurich (up to γ = 5) and the sawcut-type assembly at 35° in a Heard-type apparatus at Manchester University (up to γ = 1.2). All samples have been studied by optical microscopy, to investigate the evolution of the microstructure with strain, and by XRD analysis, to determine whether and to what extent gypsum dehydrated during deformation. In torsion, the shear stress increased with the strain rate and decreased with the temperature. In general a peak stress was reached at γ between 0.5 and 1 (at higher temperatures is reached sooner). After the peak, a various amount of weakening occurred, and mechanical 'steady state' conditions were never reached. Weakening was up to 30-40%. Most of the times the jacket failure ended prematurely the experiment. The microstructure evolved from a deformation microstructure, where grains changed shape according to the bulk strain imposed, into a recrystallization microstructure, where grains were more aequant. Grain boundary migration recrystallization was very effective in resetting the microstructure after γ of 1 or 2. In the samples deformed using saw

  1. Thermal Dehydration Kinetics of Gypsum and Borogypsum under Non-isothermal Conditions

    Institute of Scientific and Technical Information of China (English)

    I.Y.Elbeyli; S.Piskin

    2004-01-01

    Thermal dehydration of gypsum and borogypsum was investigated under nonisothermal conditions in air by using simultaneous thermogravimetric-differential thermal analyzer. Nonisothermal experiments were carried out at various linear heating rates. Kinetics of dehydration in the temperature range of 373-503 K were evaluated from the DTA (differential thermal analysis)-TGA (thermogravimetric analysis) data by means of Coats-Redfern,Kissinger and Doyle Equations. Values of the activation energy and the pre-exponential factor of the dehydration were calculated. The results of thermal experiments and kinetic parameters indicated that borogypsum is similar to gypsum from dehydration mechanism point of view although it consists of boron and small amount of alkali metal oxides.

  2. Gypsum treated fly ash as a liner for waste disposal facilities

    Energy Technology Data Exchange (ETDEWEB)

    Baig, A.A.; Sivapullaiah, P.V. [Indian Inst. of Science, Bangalore (India)

    2009-07-01

    Fly ash is now being used in geotechnical engineering and construction applications as a means of reducing the environmental impacts of fly ash generated in thermal power plants. Various additions are used to improve fly ash properties. This abstract discussed a study conducted to investigate lime and gypsum additions to fly ash. Lime amendments ranged from 0 to 10 per cent, while gypsum additions ranged from 0 to 2.5 per cent. Laboratory experiments were conducted to determine the hydraulic conductivity of compacted samples in moulds. The study showed wide variations in hydraulic conductivity for the various samples. The physico-chemical, chemical, and mineralogical changes in the fly ash amended samples were discussed.

  3. Crawling spot thermal nondestructive testing (NDT) for plaster inspection and comparison with dynamic thermography with extended heating

    Science.gov (United States)

    Bison, Paolo G.; Braggiotti, Alberto; Bressan, Chiara; Grinzato, Ermanno G.; Marinetti, Sergio; Mazzoldi, Andrea; Vavilov, Vladimir P.

    1995-03-01

    Defects in building materials located parallel to the front surface, like plaster detachment, or perpendicularly, such as cracks, are detected creating a space-varying heat flux. A variant of the `flying spot' technique called `crawling spot' was developed in order to fit requirements of these materials. This nondestructive method is performed with a localized radiant heating of the surface and synchronized local temperature measurement in the IR band. The identification of delaminations and cracks was theoretically and experimentally studied using two different procedures. Results obtained for plaster detachments were compared with dynamic thermography, applied with an extended excitation of the surface and analysis of the normalized thermal contrast both in amplitude and time. Another technique requires a continuously moving spot to heat the surface while a sequence of thermograms is recorded. The temperature profile of each pixel has to be reconstructed according to the spot speed and trajectory. This procedure was applied to stone crack detection. The experimental apparatus is thoroughly described.

  4. Computer-aided design provisionalization and implant insertion combined with optical scanning of plaster casts and computed tomography data

    Science.gov (United States)

    Hara, Shingo; Mitsugi, Masaharu; Kanno, Takahiro; Tatemoto, Yukihiro

    2014-01-01

    The conventional implant prosthesis planning process currently involves confirmation of two-dimensional anatomical findings or the quantity and quality of bones using panoramic X-ray images. The introduction of computed tomography (CT) into the field has enabled the previously impossible confirmation of three-dimensional findings, making implant planning in precise locations possible. However, artifacts caused by the presence of metal prostheses can become problematic and can result in obstacles to diagnosis and implant planning. The most updated version of SimPlant® Pro has made it possible to integrate plaster cast images with CT data using optical scanning. Using this function, the obstacles created by metal prostheses are eliminated, facilitating implant planning at the actual intraoral location. Furthermore, a SurgiGuide® based on individual patient information can be created on plaster casts, resulting in easier and more precise implant insertion. PMID:24987602

  5. Accuracy of Gypsum Casts after Different Impression Techniques and Double Pouring.

    Science.gov (United States)

    Silva, Stephania Caroline Rodolfo; Messias, Aion Mangino; Abi-Rached, Filipe de Oliveira; de Souza, Raphael Freitas; Reis, José Maurício Dos Santos Nunes

    2016-01-01

    This study evaluated the accuracy of gypsum casts after different impression techniques and double pouring. Ten patients were selected and for each one it was obtained 5 partial putty/wash impressions with vinyl polysiloxane (VPS) material from teeth #13 to #16 with partial metal stock trays. The following techniques were performed: (1) one-step; two-step relief with: (2) PVC film; (3) slow-speed tungsten carbide bur and scalpel blade, (4) small movements of the tray and (5) without relief-negative control. The impressions were disinfected with 0.5% sodium hypochlorite for 10 minutes and stored during 110 and 230 minutes for the first and second pouring, respectively, with type IV gypsum. Three intra-oral lateral photographs of each patient were taken using a tripod and a customized radiographic positioner. The images were imported into ImageJ software and the total area of the buccal surface from teeth #13 to #16 was measured. A 4.0% coefficient of variance was criterion for using these measurements as Baseline values. The casts were photographed and analyzed using the same standardization for the clinical images. The area (mm2) obtained from the difference between the measurements of each gypsum cast and the Baseline value of the respective patient were calculated and analyzed by repeated-measures two way-ANOVA and Mauchly's Sphericity test (α = 0.05). No significant effect was observed for Impression technique (P = 0.23), Second pouring (P = 0.99) and their interaction (P = 0.25). The impression techniques and double pouring did not influence the accuracy of the gypsum casts.

  6. Use of textile fibres in the reinforcement of a gypsum-cork based composite material

    OpenAIRE

    Vasconcelos, Graça; Camões, Aires; Fangueiro, Raúl, ed. lit.; Vila-Chã, Nuno; Jesus, Carlos M. G.; Cunha, Fernando Eduardo Macedo

    2013-01-01

    The study presented herein focus on the analysis of a series of experimental tests aiming at characterizing the performance of distinct textile fibers acting as a reinforcement of a gypsum-cork composite material. Two groups of textile fibers were selected, namely synthetic fibers (glass and basalt) and natural fibers (banana and sisal). The reinforced composite material was submitted to distinct types of loading, namely compression tests, which it was possible to obtain the compressive stren...

  7. The effect of gypsum products and separating materials on the typography of denture base materials.

    Science.gov (United States)

    Firtell, D N; Walsh, J F; Elahi, J M

    1980-09-01

    The typography of polymethyl methacrylate processed against various gypsum products coated with various separating materials was studied under an SEM. Tinfoil and two commercial tin foil substitutes were used as separating material during processing, and the surfaces of the resulting acrylic resin forms were studied for topographical differences. Tinfoil and alpha 2 hemihydrates produced the smoothest surfaces. As a practical solution, a good quality tinfoil substitute and alpha 1 hemihydrate could be used when processing polymethyl methacrylate resin.

  8. Treatment of localized neuropathic pain of different etiologies with the 5% lidocaine medicated plaster – a case series

    OpenAIRE

    Likar R; Demschar S; Kager I; Neuwersch S; Pipam W; Sittl R

    2014-01-01

    Rudolf Likar,1 Susanne Demschar,1 Ingo Kager,1 Stefan Neuwersch,1 Wolfgang Pipam,1 Reinhard Sittl2 1Department of Anesthesiology and Intensive Care, Hospital Klagenfurt, Klagenfurt, Austria; 2Department of Anesthesiology, Interdisciplinary Pain Centre, University Hospital Erlangen, Erlangen, Germany Objective: To assess the efficacy and safety of the topical 5% lidocaine medicated plaster in the treatment of localized neuropathic pain. Study design: This was a case series at an Austrian pain...

  9. POTENTIAL APPLICATIONS OF TRANSPARENT FABRIC BASED ON NANOFIBRES FOR THE STRENGTHENING OF PLASTERS DECORATED WITH PAINTINGS AND FRESCOES

    Directory of Open Access Journals (Sweden)

    Klára Kroftová

    2015-10-01

    Full Text Available Nanomaterials have been increasingly used in the construction industry in the last decades. Nanomaterials have been tested in specific applications focusing on the restoration and conservation of heritage buildings, mainly their surfaces. Nanofibre materials represent a separate area within this field of research and their applications in the construction and conservation practice are still very limited. The article summarizes the possibilities of strengthening plasters decorated with wall paintings with nanomaterials.

  10. Mercury transportation in soil via using gypsum from flue gas desulfurization unit in coal-fired power plant.

    Science.gov (United States)

    Wang, Kelin; Orndorff, William; Cao, Yan; Pan, Weiping

    2013-09-01

    The mercury flux in soils was investigated, which were amended by gypsums from flue gas desulphurization (FGD) units of coal-fired power plants. Studies have been carried out in confined greenhouses using FGD gypsum treated soils. Major research focus is uptakes of mercury by plants, and emission of mercury into the atmosphere under varying application rates of FGD gypsum, simulating rainfall irrigations, soils, and plants types. Higher FGD gypsum application rates generally led to higher mercury concentrations in the soils, the increased mercury emissions into the atmosphere, and the increased mercury contents in plants (especially in roots and leaves). Soil properties and plant species can play important roles in mercury transports. Some plants, such as tall fescue, were able to prevent mercury from atmospheric emission and infiltration in the soil. Mercury concentration in the stem of plants was found to be increased and then leveled off upon increasing FGD gypsum application. However, mercury in roots and leaves was generally increased upon increasing FGD gypsum application rates. Some mercury was likely absorbed by leaves of plants from emitted mercury in the atmosphere.

  11. Implications of moisture content determination in the environmental characterisation of FGD gypsum for its disposal in landfills

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Ayuso, E. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris s/n, 08028 Barcelona (Spain)], E-mail: ealvarez@ija.csic.es; Querol, X. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris s/n, 08028 Barcelona (Spain); Tomas, A. [Endesa Generacion, S.A., C/ Ribera de Loira 60, 28042 Madrid (Spain)

    2008-05-01

    The leachable contents of elements of environmental concern considered in the Council Decision 2003/33/EC on waste disposal were determined in flue gas desulphurisation (FGD) gypsum. To this end, leaching tests were performed following the standard EN-12457-4 which specifies the determination of the dry mass of the material at 105 deg. C and the use of a liquid to solid (L/S) ratio of 10 l kg{sup -1} dry matter. Additionally, leaching tests were also carried out taking into account the dry mass of the material at 60 deg. C and using different L/S ratios (2, 5, 8, 10, 15 and 20 l kg{sup -1} dry matter). It was found that the dry mass determination at 105 deg. C turns out to be inappropriate for FGD gypsum since at this temperature gypsum transforms into bassanite, and so, in addition to moisture content, crystalline water is removed. As a consequence the moisture content is overvalued (about 16%), what makes consider a lower L/S ratio than that specified by the standard EN-12457-4. As a result the leachable contents in FGD gypsum are, in general, overestimated, what could lead to more strict environmental requirements for FGD gypsum when considering its disposal in landfills, specially concerning those elements (e.g., F) risking the characterisation of FGD gypsum as a waste acceptable at landfills for non-hazardous wastes.

  12. Mercury transportation in soil via using gypsum from flue gas desulfurization unit in coal-fired power plant

    Institute of Scientific and Technical Information of China (English)

    Kelin Wang; William Orndorff; Yan Cao; Weiping Pan

    2013-01-01

    The mercury flux in soils was investigated,which were amended by gypsums from flue gas desulphurization (FGD) units of coalfired power plants.Studies have been carried out in confined greenhouses using FGD gypsum treated soils.Major research focus is uptakes of mercury by plants,and emission of mercury into the atmosphere under varying application rates of FGD gypsum,simulating rainfall irrigations,soils,and plants types.Higher FGD gypsum application rates generally led to higher mercury concentrations in the soils,the increased mercury emissions into the atmosphere,and the increased mercury contents in plants (especially in roots and leaves).Soil properties and plant species can play important roles in mercury transports.Some plants,such as tall fescue,were able to prevent mercury from atmospheric emission and infiltration in the soil.Mercury concentration in the stem of plants was found to be increased and then leveled off upon increasing FGD gypsum application.However,mercury in roots and leaves was generally increased upon increasing FGD gypsum application rates.Some mercury was likely absorbed by leaves of plants from emitted mercury in the atmosphere.

  13. Histological Comparison in Rats between Carbonate Apatite Fabricated from Gypsum and Sintered Hydroxyapatite on Bone Remodeling

    Directory of Open Access Journals (Sweden)

    Yasunori Ayukawa

    2015-01-01

    Full Text Available Carbonate apatite (CO3Ap, the form of apatite found in bone, has recently attracted attention. The purpose of the present study was to histologically evaluate the tissue/cellular response toward the low-crystalline CO3Ap fabricated using a dissolution-precipitation reaction with set gypsum as a precursor. When set gypsum was immersed in a 100°C 1 mol/L Na3PO4 aqueous solution for 24 h, the set gypsum transformed into CO3Ap. Both CO3Ap and sintered hydroxyapatite (s-HAp, which was used as a control, were implanted into surgically created tibial bone defects of rats for histological evaluation. Two and 4 weeks after the implantation, histological sections were created and observed using light microscopy. The CO3Ap granules revealed both direct apposition of the bone matrix by osteoblasts and osteoclastic resorption. In contrast, the s-HAp granules maintained their contour even after 4 weeks following implantation which implied that there was a lack of replacement into the bone. The s-HAp granules were sometimes encapsulated with fibrous tissue, and macrophage polykaryon was occasionally observed directly apposed to the implanted granules. From the viewpoint of bone remodeling, the CO3Ap granules mimicked the bone matrix, suggesting that CO3Ap may be an appropriate bone substitute.

  14. Do Ca2+-adsorbing ceramics reduce the release of calcium ions from gypsum-based biomaterials?

    Science.gov (United States)

    Belcarz, Anna; Zalewska, Justyna; Pałka, Krzysztof; Hajnos, Mieczysław; Ginalska, Grazyna

    2015-02-01

    Bone implantable materials based on calcium sulfate dihydrate dissolve quickly in tissue liquids and release calcium ions at very high levels. This phenomenon induces temporary toxicity for osteoblasts, may cause local inflammation and delay the healing process. Reduction in the calcium ion release rate by gypsum could be therefore beneficial for the healing of gypsum-filled bone defects. The aim of this study concerned the potential use of calcium phosphate ceramics of various porosities for the reduction of high Ca(2+) ion release from gypsum-based materials. Highly porous ceramics failed to reduce the level of Ca(2+) ions released to the medium in a continuous flow system. However, it succeeded to shorten the period of high calcium level. It was not the phase composition but the high porosity of ceramics that was found crucial for both the shortening of the Ca(2+) release-related toxicity period and intensification of apatite deposition on the composite. Nonporous ceramics was completely ineffective for this purpose and did not show any ability to absorb calcium ions at a significant level. Moreover, according to our observations, complex studies imitating in vivo systems, rather than standard tests, are essential for the proper evaluation of implantable biomaterials.

  15. Surface induced constant composition crystal growth kinetics studies. The brushite gypsum system

    Science.gov (United States)

    Hina, A.; Nancollas, G. H.; Grynpas, M.

    2001-02-01

    The possible oriented growth of one crystalline phase on the surface of another is especially important in systems containing both phosphate and sulfate salts of calcium. Whether the overgrowth results from a true epitaxial relationship is dependent on factors such as the thermodynamic driving forces and the free energies of the surfaces. Despite the fact that calcium sulfate dihydrate (CSD, gypsum) and calcium hydrogen phosphate dihydrate (DCPD, brushite) show many crystallographic and structural analogies, their surface reactions are quite different. The nucleation and growth of gypsum on brushite surfaces has been investigated in supersaturated solutions of calcium sulfate dihydrate at 25.0°C using the constant composition (CC) method. During the kinetics experiments, the harvested solid phases were examined by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and energy dispersive X-ray analysis (EDS). Induction periods, τ, preceding the initial formation of gypsum crystals at the brushite surfaces, varied markedly with relative supersaturation, σ. A thin layer wicking method was used to investigate the interfacial free energies of the growing phases, and these data were also calculated from the kinetics results. The interfacial free energy, γ, estimated from initial growth rates was 8.4 mJ m -2, while that calculated from the induction times was 8.9 mJ m -2. These values were in agreement with those determined directly using thin layer wicking.

  16. Risk minimisation of FGD gypsum leachates by incorporation of aluminium sulphate

    Energy Technology Data Exchange (ETDEWEB)

    Alvarez-Ayuso, E. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain); Department of Environmental Geochemistry, IRNASA, CSIC, Apto. 257, 37071 Salamanca (Spain)], E-mail: ealvarez@ija.csic.es; Querol, X. [Department of Environmental Geology, Institute of Earth Sciences ' Jaume Almera' (CSIC), C/ Lluis Sole i Sabaris, s/n, 08028 Barcelona (Spain); Ballesteros, J.C.; Gimenez, A. [Endesa Generacion, S.A., C/ Ribera de Loira, 60, 28042 Madrid (Spain)

    2008-11-15

    The incorporation of aluminium sulphate to (flue gas desulphurisation) FGD gypsum before its disposal was investigated as a way to minimise the risk supposed by the high fluoride content of its leachates. Using a bath method the kinetic and equilibrium processes of fluoride removal by aluminium sulphate were studied at fluoride/aluminium molar concentration (F/Al) ratios in the range 1.75 10{sup -2}-1.75 under the pH conditions (about 6.5) of FGD gypsum leachates. It was found that fluoride removal was a very fast process at any of the (F/Al) ratios subject of study, with equilibrium attained within the first 15 min of interaction. High decreases in solution fluoride concentrations (50-80%) were found at the equilibrium state. The use of aluminium sulphate in the stabilization of FGD gypsum proved to greatly decrease its fluoride leachable content (in the range 20-90% for aluminium sulphate doses of 0.1-5%, as determined by the European standard EN 12457-4). Such fluoride leaching minimisation assures the characterization of this by-product as a waste acceptable at landfills for non-hazardous wastes according to the Council Decision 2003/33/EC on waste disposal. Furthermore, as derived from column leaching studies, the proposed stabilization system showed to be highly effective in simulated conditions of disposal, displaying fluoride leaching reduction values about 55 and 80% for aluminium sulphate added amounts of 1 and 2%, respectively.

  17. Developing biodiversity indicators on a stakeholders' opinions basis: the gypsum industry Key Performance Indicators framework.

    Science.gov (United States)

    Pitz, Carline; Mahy, Grégory; Vermeulen, Cédric; Marlet, Christine; Séleck, Maxime

    2016-07-01

    This study aims to establish a common Key Performance Indicators (KPIs) framework for reporting about the gypsum industry biodiversity at the European level. In order to integrate different opinions and to reach a consensus framework, an original participatory process approach has been developed among different stakeholder groups: Eurogypsum, European and regional authorities, university scientists, consulting offices, European and regional associations for the conservation of nature, and the extractive industry. The strategy is developed around four main steps: (1) building of a maximum set of indicators to be submitted to stakeholders based on the literature (Focus Group method); (2) evaluating the consensus about indicators through a policy Delphi survey aiming at the prioritization of indicator classes using the Analytic Hierarchy Process method (AHP) and of individual indicators; (3) testing acceptability and feasibility through analysis of Environmental Impact Assessments (EIAs) and visits to three European quarries; (4) Eurogypsum final decision and communication. The resulting framework contains a set of 11 indicators considered the most suitable for all the stakeholders. Our KPIs respond to European legislation and strategies for biodiversity. The framework aims at improving sustainability in quarries and at helping to manage biodiversity as well as to allow the creation of coherent reporting systems. The final goal is to allow for the definition of the actual biodiversity status of gypsum quarries and allow for enhancing it. The framework is adaptable to the local context of each gypsum quarry.

  18. Mechanical properties of simulated Mars materials: gypsum-rich sandstones and lapilli tuff

    Science.gov (United States)

    Morrow, Carolyn; Lockner, David; Okubo, Chris

    2013-01-01

    Observations by the Mars Exploration Rover (MER) Opportunity, and other recent studies on diagenesis in the extensive equatorial layered deposits on Mars, suggest that the likely lithologies of these deposits are gypsum-rich sandstones and tuffaceous sediments (for example, Murchie and others, 2009; Squyres and others, 2012; Zimbelman and Scheidt, 2012). Of particular interest is how the diagenesis history of these sediments (degree of cementation and composition) influences the strength and brittle behavior of the material. For instance, fractures are more common in lower porosity materials under strain, whereas deformation bands, characterized by distributed strain throughout a broader discontinuity in a material, are common in higher porosity sedimentary materials. Such discontinuities can either enhance or restrict fluid flow; hence, failure mode plays an important role in determining the mechanics of fluid migration through sediments (Antonellini and Aydin, 1994; 1995; Taylor and Pollard, 2000; Ogilvie and Glover, 2001). As part of a larger study to characterize processes of fault-controlled fluid flow in volcaniclastic and gypsum-rich sediments on Mars, we have completed a series of laboratory experiments to focus on how gypsum clast content and degree of authigenic cementation affects the strength behavior of simulated Mars rocks. Both axial deformation and hydrostatic pressure tests were done at room temperature under dry conditions.

  19. The Influence of FeS on the Thermal Decomposition Characteristics of Gypsum in the Nitrogen Atmosphere%氮气气氛下FeS对二水石膏热分解特性的影响

    Institute of Scientific and Technical Information of China (English)

    张亚杰; 贾兴文

    2012-01-01

    To study the influence of FeS, as reducing agent, on thermal decomposition characteristics of gypsum and to calculate the active energy required for gypsum decomposition with different proportion of reducing agent, the method of TG-DSC and the model of Coats-Redfem were adopted respectively. The study used Nitrogen as carrier gas to prevent reducing agent from oxidation. Results showed that when the ration of molar mass between FeS and gypsum was increased from 1 : 22 to 3 : 22, the activation energy value decreased from 327 kJ/mol to 214 kJ/ mol; accordingly, the initial decomposition temperature fell from 1350 ℃ to 998 ℃. The decomposition characteristics of gypsum represented similar tendency when the molar mass ratio of coke and gypsum increased from 1 : 2 to 2 : 1 apart from a slump in the initial decomposition temperature from 1350 ℃ to 956 ℃. Besides, the product Fe2O3 has positive effects on the sequential decomposition,of gypsum.%采用TG-DSC方法分析FeS做还原剂时化学纯石膏的热分解特性,并利用Coats-Redfem模型计算还原剂掺量不同时石膏分解的活化能值.为防止还原剂被氧化选择氮气作为载气流.结果表明,焦炭与石膏摩尔比从1∶2增加到2∶1时,石膏分解所需的活化能从327 kJ/mol降低到210 kJ/mol,起始温度从1350℃降到956℃;FeS与石膏的摩尔比从1∶22增加到3∶22时,石膏分解所需的活化能值从327 kJ/mol降低到214 kJ/mol,起始分解温度从1350℃降低到998℃,同时生成的产物Fe2O3对石膏的分解有促进作用.

  20. 5% lidocaine medicated plaster versus pregabalin in post-herpetic neuralgia and diabetic polyneuropathy: an open-label, non-inferiority two-stage RCT study.

    Science.gov (United States)

    Baron, Ralf; Mayoral, Victor; Leijon, Göran; Binder, Andreas; Steigerwald, Ilona; Serpell, Michael

    2009-07-01

    To compare efficacy and safety of 5% lidocaine medicated plaster with pregabalin in patients with post-herpetic neuralgia (PHN) or painful diabetic polyneuropathy (DPN). This was a two-stage adaptive, randomized, open-label, multicentre, non-inferiority study. Data are reported from the initial 4-week comparative phase, in which adults with PHN or painful DPN received either topical 5% lidocaine medicated plaster applied to the most painful skin area or twice-daily pregabalin capsules titrated to effect according to the Summary of Product Characteristics. The primary endpoint was response rate at 4 weeks, defined as reduction averaged over the last three days from baseline of > or = 2 points or an absolute value of plaster and 61.5% receiving pregabalin were considered responders (corresponding numbers for the per protocol set, PPS: 65.3% vs. 62.0%). In PHN more patients responded to 5% lidocaine medicated plaster treatment than to pregabalin (PPS: 62.2% vs. 46.5%), while response was comparable for patients with painful DPN (PPS: 66.7% vs 69.1%). 30% and 50% reductions in NRS-3 scores were greater with 5% lidocaine medicated plaster than with pregabalin. Both treatments reduced allodynia severity. 5% lidocaine medicated plaster showed greater improvements in QoL based on EQ-5D in both PHN and DPN. PGIC and CGIC scores indicated greater improvement for 5% lidocaine medicated plaster treated patients with PHN. Improvements were comparable between treatments in painful DPN. Fewer patients administering 5% lidocaine medicated plaster experienced AEs (safety set, SAF: 18.7% vs. 46.4%), DRAEs (5.8% vs. 41.2%) and related discontinuations compared to patients taking pregabalin. 5% lidocaine medicated plaster showed better efficacy compared with pregabalin in patients with PHN. Within DPN, efficacy was comparable for both treatments. 5% lidocaine medicated plaster showed a favourable efficacy/safety profile with greater improvements in patient satisfaction and Qo

  1. The next chapter in experimental petrology: Metamorphic dehydration of polycrystalline gypsum captured in 3D microtomographic time series datasets

    Science.gov (United States)

    Bedford, John; Fusseis, Florian; Leclere, Henry; Wheeler, John; Faulkner, Dan

    2016-04-01

    Nucleation and growth of new minerals in response to disequilibrium is the most fundamental metamorphic process. However, our current kinetic models of metamorphic reactions are largely based on inference from fossil mineral assemblages, rather than from direct observation. The experimental investigation of metamorphism has also been limited, typically to concealed vessels that restrict the possibility of direct microstructural monitoring. Here we present one of the first time series datasets that captures a metamorphic reaction, dehydration of polycrystalline gypsum to form hemihydrate, in a series of three dimensional x-ray microtomographic datasets. We achieved this by installing an x-ray transparent hydrothermal cell (Fusseis et al., 2014, J. Synchrotron Rad. 21, 251-253) in the microtomography beamline 2BM at the Advanced Photon Source (USA). In the cell, we heated a millimetre-sized sample of Volterra Alabaster to 388 K while applying an effective pressure of 5 MPa. Using hard x-rays that penetrate the pressure vessel, we imaged the specimen 40 times while it reacted for approximately 10 hours. Each microtomographic dataset was acquired in 300 seconds without interrupting the reaction. Our absorption microtomographic data have a voxel size of 1.3 μm, which suffices to analyse the reaction progress in 4D. Gypsum can clearly be distinguished from hemihydrate and pores, which form due to the large negative solid volume change. On the resolved scale, the first hemihydrate needles appear after about 2 hours. Our data allow tracking of individual needles throughout the entire experiment. We quantified their growth rates by measuring their circumference. While individual grains grow at different rates, they all start slowly during the initial nucleation stage, then accelerate and grow steadily between about 200 and 400 minutes before reaction rate decelerates again. Hemihydrate needles are surrounded by porous haloes, which grow with the needles, link up and

  2. Laboratory Salinization of Brazilian Alluvial Soils and the Spectral Effects of Gypsum

    Directory of Open Access Journals (Sweden)

    Luis Clenio J. Moreira

    2014-03-01

    Full Text Available Irrigation-induced salinization is an important land degradation process that affects crop yield in the Brazilian semi-arid region, and gypsum has been used as a corrective measure for saline soils. Fluvent soil samples (180 were treated with increasing levels of salinization of NaCl, MgCl2 and CaCl2. The salinity was gauged using electrical conductivity (EC. Gypsum was added to one split of these samples before they were treated by the saline solutions. Laboratory reflectance spectra were measured at nadir under a controlled environment using a FieldSpec spectrometer, a 250-W halogen lamp and a Spectralon panel. Variations in spectral reflectance and brightness were evaluated using principal component analysis, as well as the continuum-removed absorption depths of major features at 1450, 1950, 1750 and 2200 nm for both the gypsum-treated (TG and non-treated (NTG air-dried soil samples as a function of EC. Pearson’s correlation coefficients of reflectance and the band depth with EC were also obtained to establish the relationships with salinity. Results showed that NTG samples presented a decrease in reflectance and brightness with increasing CaCl2 and MgCl2 salinization. The reverse was observed for NaCl. Gypsum increased the spectral reflectance of the soil. The best negative correlations between reflectance and EC were observed in the 1500–2400 nm range for CaCl2 and MgCl2, probably because these wavelengths are most affected by water absorption, as Ca and Mg are much more hygroscopic than Na. These decreased after chemical treatment with gypsum. The most prominent features were observed at 1450, 1950 and 1750 nm in salinized-soil spectra. The 2200-nm clay mineral absorption band depth was inversely correlated with salt concentration. From these features, only the 1750 and 2200 nm ones are within atmospheric absorption windows and can be more easily measured using hyperspectral sensors.

  3. EXAFS speciation and phytoavailability of Pb in a contaminated soil amended with compost and gypsum.

    Science.gov (United States)

    Hashimoto, Yohey; Yamaguchi, Noriko; Takaoka, Masaki; Shiota, Kenji

    2011-02-01

    Due to unregulated uses of lead pellets for hunting purposes in Japan, soils and sediments in some river basins and wetlands have become highly contaminated with Pb. Deterioration of natural vegetation has occurred sporadically in these areas, and therefore revegetation is needed for ecological restoration. The objectives of the present study were to assess the effects of surface applications of compost and gypsum amendments on Pb availability to a watercress plant (Nasturtium officinale W.T. Aiton) and molecular-scale speciation of Pb in soil solid phases. The compost and gypsum amendments significantly decreased dissolved Pb and Sb in pore water. The concentration of Pb in aboveground plant tissues was 190mg kg(-1) in the control soil and was reduced to soils. The concentration of Sb in plants grown in the control soil was 13mg kg(-1), whereas that in the soils receiving compost and gypsum decreased below detectable levels. Redox potential was higher in vegetated soils (ave. 349mV) than in the unvegetated soils (ave. 99mV) due to oxygen introduced by plant roots. Extended X-ray absorption fine structure (EXAFS) spectroscopy illustrated that Pb occurred as Pb sorbed on birnessite and/or ferrihydrite (Pb-Mn/Fe, ~60%) and Pb sorbed on organic matter (Pb-org, ~15%), and galena (PbS, ~10%) in the vegetated and unvegetated control soils. The compost amendment increased the proportion of Pb-org by 2-fold than in the control soils. The amended soils with plant growth decreased the proportion of Pb-Mn/Fe phases by half of that without plant growth. Galena and anglesite (PbSO(4)) were not detected in compost-amended soils and even in gypsum-amended soils since a significant soil reduction to anoxic levels did not occur in the entire soil. The present study indicated that, under flooded conditions, surface applications of compost and gypsum amendments reduced plant Pb uptake from the Pb contaminated soil. Crown Copyright © 2010. Published by Elsevier B.V. All rights

  4. Reforestation and landscape reconstruction in gypsum mine area from the semiarid region of NE Brazil

    Science.gov (United States)

    Bittar, S. M. B.; Straaten, P. V.; de Araujo Vieura Santos, M. de Fatima; Agra Bezerra da Silva, Y. J.; da Silva, M.; Saraiva de Melo Pinheiro, T.; Gusmao Didier de Moraes, F.; de Aguiar Accioly, A. M.; Alves de Santana, S. R.; dos Santos, H. A.; de Carvalho, D. M.; de Lima Ferreira, G.; de Carvalho Santos, C.

    2012-04-01

    In the Araripe region, Northeast Brazil, exist the world's second largest reserve of gypsum, estimated at over than one billion tons, which accounts for 95% of the Brazilian production and constitutes an important segment of the regional economy. The gypsum deposit occurs in the Lower Cretaceous Santana Formation of the Araripe basin, which is constituted by siltstones, marls, limestones, shales and gypsum layers. The ore extraction is from an open pit, on simple benches with a height of about 15 meters. Activities in mining operations involve stripping, drilling, loading explosives, blast, fragmentation and block loading / transport. Currently, gypsum mining and processing results in major changes in the landscape (pits and wastes heaps sedimentary rocks and soil mixture), deforestation of the "caatinga" ecosystem for use as firewood in small calcinations, dust pollution and changes in hydrology. To promote environmental remediation of this area, a multidisciplinary research has being done with the aim to support reforestation at the wastes heaps. The study involved the following activities: collection and physical, chemical and mineralogical characterization of mine waste materials; a floristic survey around the mines (botanical identification and measuring physical parameters in 16 plots, in order to identify which species are best suited to the conditions of the substrate at the mine site); an experiment (randomized block design) developed in a greenhouse, where seedlings of various native tree species were grown in a "constructed soil" made up of gypsum waste combined with chicken, goat and cattle manure, aimed to select tree species and soil treatment to be used in a waste heap; and an assessment of water quality for irrigation of the reforestation areas. The waste materials consist of large clayey aggregates, which may present physical/chemical properties unfavorable for plant development. The mineralogy of the sand fraction (> 85% quartz, gypsum and

  5. [Clinical observation of dog days moxibustion plaster therapy in treatment of allergic rhinitis of different patterns/syndromes].

    Science.gov (United States)

    Lin, Yong-kai; Liang, Gui-hong; Huang, Yu-xin; Sun, He; Zhang, Tian-cheng; Qu, Chong-zheng

    2014-10-01

    To explore the efficacy and feasibility of dog days moxibustion plaster therapy in treatment of allergic rhinitis of different patterns/syndromes. Allergic rhinitis of lung deficiency and invasion of cold, spleen qi deficiency and kidney yang deficiency, 56 patients for each pattern/syndrome were randomized into a plaster therapy group and a nasal spray group, 28 cases in each one. In the plaster therapy group, according to the pattern/syndrome differentiation, with literature retrieval method, 3 acupoints of high frequency utility in clinic were selected as one group in acupoint plaster therapy. For lung deficiency and invasion of cold pattern/syndrome, Feishu (BL 13), Fengmen (BL 12) and Hegu (LI 4) were selected. For spleen qi deficiency pattern/syndrome, Pishu (BL 21), Zusanli (ST 36) and Dazhui (GV 14) were selected. For kidney yang deficiency pattern/ syndrome, Shenshu (BL 23), Dingchuan (EX-B 1) and Bailao (EX-HN 15) were selected. Separately, on July 13, 2013, July 23, 2013, August 2, 2013 and August 12, 2013, the aucpoint plaster therapy was applied, 2 to 4 h (1 to 2 h for children) each time. In the nasal spray group, beclometasone dipropionate aqueous nasal spray, 2 presses one nostril each time, 2 to 3 times a day, continuously for 4 weeks. The symptom score and efficacy were compared before and after treatment in the patients of the two groups. The symptom scores of 3 patterns/syndromes were all apparently improved after treatment as compared with those before treatment in the patients of the two groups (all Pplaster therapy group was better than that of the nasal spray group (Pplaster therapy group, better than 84.6% (22/26) in the nasal spray group (Pplaster therapy group, obviously better than 76.9% (22/26) in the nasal spray group (Pplaster therapy group, better than 76.9% (22/26) in the nasal spray group (Pplaster therapy achieves definite efficacy on allergic rhinitis at the acupoints selected based on the differentiation of different patterns

  6. Studies on termite hill and lime as partial replacement for cement in plastering

    Energy Technology Data Exchange (ETDEWEB)

    Olusola, K.O.; Olanipekun, E.A.; Ata, O.; Olateju, O.T. [Obafemi Awolowo University, Ile-Ife, Osun State (Nigeria). Department of Building

    2006-03-15

    This study investigated the compressive strength and water absorption capacity of 50x50x50mm mortar cubes made from mixes containing lime, termite hill and cement and sand. Two mix ratios (1:4 and 1:6) and varying binder replacements of cement with lime or termite hill amounting to 0%, 10%, 20%, 30%, 40% and 50% were used. Test results showed that the compressive strength of the mortar cubes increases with age and decreases with increasing percentage replacement of cement with lime and termite hill. However, for mix ratio 1:6, up to 20% replacement of cement with either lime or termite hill, all the mortar cubes had the same strength; subsequently, the termite hill exhibited a higher compressive strength. For mix ratio 1:4, mortar cubes made from lime/cement and termite hill/cement mixtures had the same strength at 50% replacement. Generally, water absorption is higher in mixtures containing lime (18.10% and 14.20% for mix ratios 1:6 and 1:4, respectively, both at 50% replacement level) than those containing termite hill (16.10% and 13.02% for mix ratios 1:6 and 1:4, respectively, both at 50% replacement level). Termite hills seem to be promising as a suitable, locally available housing material for plastering. (author)

  7. Effective and Economic Offloading of Diabetic Foot Ulcers in India with the Bohler Iron Plaster Cast.

    Science.gov (United States)

    Saikia, Priyanka; Hariharan, Rajalakshmi; Shankar, Nachiket; Gaur, Anil Kumar; Jose, Naveen Matthew

    2016-04-01

    Economic constraints are a major obstacle to the implementation of offloading casts in India. The aim of this study is to monitor the healing and activity limitations related to Bohler iron plaster cast (BIPC) when used for offloading diabetic neuropathic plantar foot ulcers. Thirty patients were cast for 1 month and evaluated for healing using the Pressure Ulcer Scale for Healing (PUSH), and for activity limitation using the Lower Extremity Functional Scale (LEFS). The change in the scores after intervention was the outcome measure. There was good healing as evidenced by a statistical difference in mean PUSH scores. The baseline PUSH score of 9.76-0.41 (T1-SEM) was greater than follow-up PUSH score of 6.32 + 0.41 (T2 + SEM) and the p value ulcer area, exudate, and tissue type. There was no mobility effect as there was no significant difference in LEFS. Significant negative correlation was there between PUSH and LEFS. The r value was less than -0.7 both at baseline and after intervention. The combined benefits of good healing, lack of affect on lower extremity function, the ease of application and dressing, and relative affordability make BIPC a commendable offloading modality for the management of diabetic plantar ulcers.

  8. Soil Application of Tannery Land Plaster: Effects on Nitrogen Mineralization and Soil Biochemical Properties

    Directory of Open Access Journals (Sweden)

    Caterina Giacometti

    2012-01-01

    Full Text Available Tannery land plaster (TLP is a byproduct of lime hydrolysis of leather shavings. Its use in agriculture (organic C ≈ 17%, N ≈ 6% dm could represent an alternative to landfill or incineration, but the high Cr(III content (≈5% dm makes it necessary to evaluate the effect on soil biochemical properties. TLP was therefore added at the rates of 220 and 440 kg of N ha−1 to 2 agricultural soils and incubated for 56 days under controlled conditions. Extractable NH4 +-N and NO3 −-N, CO2-C evolution, microbial biomass-N, protease activity, and extractable Cr were monitored. The organic N was readily mineralized (>50% in the first week and a significant increase in microbial activity was measured, regardless of soil type and addition rate. Extractable Cr(III quickly decreased during the incubation. The absence of a negative impact on soil biochemical properties seems to support the use of TLP in agriculture, although further investigations in long-term field experiments are suggested.

  9. Study on Tongkuaixiao Babu Plaster(痛块消巴布剂)in Treating Cancer Pain

    Institute of Scientific and Technical Information of China (English)

    万冬桂; 李佩文

    2004-01-01

    Objective: To explore the efficacy of Tongkuaixiao Babu plaster (痛块消巴剂, TKXBBP)in treating cancer pain. Methods: In the clinical observation, sixty-five patients with moderate or severe cancer pain were randomly divided into two groups: 32 in the treated group (TKXBBP group) and 33 in the control group (Bucinnazine group). The therapeutic effects in relieving pain, improving quality of life (QOL),and the rate of satisfaction the patients felt of the two groups were compared respectively. Results: TKXBBP was effective in treating cancer pain. There wasn't any statistically significant difference in total effective rate (P>0.05), but the statistical difference was significant in obvious remission rate (P<0.05) between the treated and control group, and the effect on serious pain shown in the treated group was better than that of the control group (P<0.05). The difference in the initiation time of relieving cancer pain was insignificant (P>0.05), while in the remission period, the treated group showed its treatment was obviously superior to that of the control group (P<0.05). TKXBBP showed better effect in the improvement of QOL (P<0.05)and satisfaction rate, with significant difference between the treated and the control groups (P<0.01). Conclusion: TKXBBP's effect in treating cancer pain was obvious, its application was safe and convenient. It was shown that the external treatment with this kind of Chinese medicine had great advantage in treating cancer pain.

  10. Effect of 5% lidocaine medicated plaster on pain intensity and paroxysms in classical trigeminal neuralgia.

    Science.gov (United States)

    Tamburin, Stefano; Schweiger, Vittorio; Magrinelli, Francesca; Brugnoli, Maria Paola; Zanette, Giampietro; Polati, Enrico

    2014-11-01

    Trigeminal neuralgia (TN) is a neuropathic pain condition affecting one or more branches of the trigeminal nerve. It is characterized by unilateral, sudden, shock-like, and brief painful attacks, which follow the distribution of trigeminal nerve branches, and with no other accompanying sensorimotor or autonomic signs and symptoms. Current guidelines stipulate which therapies represent first-, second-, and third-line treatments for TN, but there is a consistent mismatch between the therapeutic guidelines and the patient's preferences and expectations. We report on 2 patients with classical TN in whom conventional drugs for TN were not tolerated. In these patients, treatment with 5% lidocaine medicated plaster (LMP) resulted in reduction of pain intensity and the number of pain paroxysms. LMP is known to block the sodium channels on peripheral nerves and may cause a selective and partial block of Aδ and C fibers. According to the TN ignition hypothesis, blockage of peripheral afferents by LMP may reduce pain paroxysms. The effect of LMP may outlast the pharmacokinetics of the drug by reducing pain amplification mechanisms in the central nervous system. LMP has limited or no systemic side effects. LMP may be an effective and well-tolerated treatment option for TN in those patients who do not tolerate or who refuse other therapies. Future randomized controlled studies should better address this issue. © The Author(s) 2014.

  11. Pain in the room of plasters of the traumatology emergency unit

    Directory of Open Access Journals (Sweden)

    Inmaculada Aponte Tomillo

    2010-03-01

    Full Text Available In the emergency department the pain is the symptom more frequent than they undergo the patients, the presence of this one is considered like a useless and unnecessary suffering since it can get to control itself by means of the drug administration. The objective of this study is to know the existence and intensity the pain and if analgesia is administered in the traumatology emergency unit. It has been realised by means of a questionnaire in that picks up the variables: sex, age, diagnosis, pain and administration of analgesia. With respect to the result it exists 39,4% of fractures of radio, followed of 24,2% of fracture of metacarpianos. The pain in the room of plasters: Visual scale Analogical EVA (10 the 15,2% and EVA (7 the 21,2% of the patients. As far as the administration of analgesia to the 59,1% of the patients no was administered to him. In conclusion, the intensity of the pain that undergoes our patients during the manipulation of the fractures is because a percentage very lifted is reduced and immobilized without analgesia administration. This high prevalence of the pain puts in prohibition the welfare quality.

  12. Efficacy and Safety of Calcipotriol Plus Betamethasone Dipropionate Aerosol Foam Compared with Betamethasone 17-Valerate-Medicated Plaster for the Treatment of Psoriasis.

    Science.gov (United States)

    Queille-Roussel, Catherine; Rosen, Monika; Clonier, Fabrice; Nørremark, Kasper; Lacour, Jean-Philippe

    2017-04-01

    Fixed combination calcipotriol as hydrate (Cal) 50 µg/g plus betamethasone as dipropionate (BD) 0.5 mg/g aerosol foam is an alcohol-free treatment for psoriasis. Betamethasone 17-valerate 2.25 mg (BV)-medicated plasters are recommended for treating psoriasis plaques localized in difficult-to-treat (DTT; elbow, knee, anterior face of the tibia) areas. The aim of this study was to compare the efficacy of Cal/BD foam with BV-medicated plaster in patients with plaque psoriasis. In this phase IIa, randomized, single-center, investigator-blinded, 4-week study, both Cal/BD foam and BV-medicated plaster were applied once daily to six test sites (three for each treatment). The primary efficacy endpoint was absolute change in total clinical score (TCS; sum of erythema, scaling, and infiltration); secondary endpoints were changes from baseline in each individual clinical score, ultrasonographic changes (total skin and echo-poor band thickness), and safety; and post hoc analysis was change from baseline in TCS on DTT areas. Thirty-five patients were included. Least-squares mean change in TCS from baseline was significantly greater for Cal/BD foam (-5.8) than BV-medicated plaster (-3.7; difference -2.2; 95% confidence interval -2.6 to -1.8; p plaster (both p plaster on DTT areas after 4 weeks (p plasters, including on DTT areas, in patients with plaque psoriasis. NCT02518048.

  13. 氟硅树脂石膏防水剂的制备与应用%Application and preparation of water-proofing fluorin silicon gypsum additive

    Institute of Scientific and Technical Information of China (English)

    潘红; 李国忠

    2011-01-01

    以有机氟﹑有机硅以及(甲基)丙烯酸酯为原料,采用溶液聚合的方法制备了氟硅树脂防水剂,探讨了软硬单体配比、反应温度和单体投入方式对防水剂性能的影响,确定了工艺参数。研究了此防水剂对石膏试样耐水性能的影响。试验结果表明:该氟硅树脂石膏防水剂对石膏试样的短期防水性能具有显著改善,但长期使用时,防水性能有一定程度的削弱。%Organic fluorine,organic silicon,and(methyl) acrylate are used to prepare a water-proofing gypsum additive which is a fluorosilicon resin by liquor polymerization method.Effects of soft hard monomer ratio,reaction temperature and the introducing model of monomers on the properties of the waterproofing additive are discussed,and the process parameters are determined.Experiment shows that the early waterproofing performance of gypsum samples with the additive is significantly improved,but the water resistance is weakened to a certain extent for a long time.

  14. Bacterial Communities and the Nitrogen Cycle in the Gypsum Soils of Cuatro Ciénegas Basin, Coahuila: A Mars Analogue

    OpenAIRE

    López-Lozano, Nguyen E.; Eguiarte, Luis E.; Bonilla-Rosso, Germán; García-Oliva, Felipe; Martínez-Piedragil, Celeste; Rooks, Christine; Souza, Valeria

    2012-01-01

    The OMEGA/Mars Express hyperspectral imager identified gypsum at several sites on Mars in 2005. These minerals constitute a direct record of past aqueous activity and are important with regard to the search of extraterrestrial life. Gale Crater was chosen as Mars Science Laboratory Curiosity's landing site because it is rich in gypsum, as are some desert soils of the Cuatro Ciénegas Basin (CCB) (Chihuahuan Desert, Mexico). The gypsum of the CCB, which is overlain by minimal carbonate deposits...

  15. Limestone, gypsum and residual effect of fertilizers in the biomass production and nutrient cycling of millet plants

    Directory of Open Access Journals (Sweden)

    Maria da Conceição Santana Carvalho

    2014-09-01

    Full Text Available Cover crops can provide a higher nutrient cycling. This study aimed to determine the effect of annual applications of gypsum and lime to the soil surface and of fertilizer doses to the previous crop (soybean in the dry biomass production and nutrient accumulation by plants of pearl millet grown in succession, under no-tillage system. The experimental design was randomized blocks, in a 4x4 factorial scheme, with four replications. Treatments consisted of the combination of four types of soil conditioner (lime, lime + gypsum, gypsum and control, split in three parts (2 t ha-1 of lime and 1,0 t ha-1 of gypsum; 2 t ha-1 of lime and 1 t ha-1 of gypsum; and 1 t ha-1 of lime and 0.5 t ha-1 of gypsum, and four fertilizing rates with P (triple and simple superphosphate and K (potassium chloride (0%, 50%, 100% and 150% of the recommended fertilizing, applied at the sowing of the previous crop (soybean. Liming provided increments in the dry biomass production and in the accumulation of nutrients (N, P, K, Ca, Mg and S by millet plants. The application of gypsum did not increase the millet dry biomass yield. The use of increasing rates of fertilizers in the previous crop (soybean increased the biomass dry matter, density and accumulation of nutrients by millet plants. The intercropping of millet as a cover crop, with the residual effect of the fertilizer applied in the summer crop, provided a nutrient cycling that can be used by the following crops.

  16. Topical 5% lidocaine (lignocaine) medicated plaster treatment for post-herpetic neuralgia: results of a double-blind, placebo-controlled, multinational efficacy and safety trial.

    Science.gov (United States)

    Binder, Andreas; Bruxelle, Jean; Rogers, Peter; Hans, Guy; Bösl, Irmgard; Baron, Ralf

    2009-01-01

    Post-herpetic neuralgia (PHN) is a distressing neuropathic pain condition mainly affecting elderly patients. Neuropathic pain symptoms can be of a burning, shooting and stabbing nature, and may continue for prolonged periods and are often poorly controlled by polymedication. The aim of this study was to evaluate the analgesic efficacy and safety of topical analgesic treatment (5% lidocaine [lignocaine] medicated plaster) compared with placebo plaster in patients with PHN. This was a double-blind, placebo plaster-controlled, parallel-group, multicentre study employing enriched enrolment with randomized withdrawal methodology. After an initial 8-week open-label, active run-in phase, responders entered a 2-week randomized, double-blind, placebo-controlled phase. The study was conducted at 33 outpatient investigational centres in 12 European countries. Patients with PHN were selected who were aged >/=50 years, had experienced neuropathic pain persisting for >/=3 months after rash healing, and had a mean pain intensity of >/=4 on an 11-point numerical rating scale. A total of 265 patients entered the open-label phase and subsequently a pre-defined number of 71 patients entered the randomized phase. Patients applied up to three 5% lidocaine medicated plasters for up to 12 hours per day. The primary endpoint of the study was time-to-exit due to a >/=2-point reduction in pain relief on two consecutive days of plaster application using a 6-point verbal rating scale. Of the 265 patients entering the run-in phase, 51.7% achieved at least moderate pain relief. In the double-blind phase (full analysis set, n = 71), median times-to-exit were 13.5 (range 2-14) and 9.0 (range 1-14) days for lidocaine and placebo plaster groups, respectively (p = 0.151). For per-protocol patients (n = 34), median time-to-exit was 14.0 (range 3-14) and 6.0 (range 1-14) days for lidocaine and placebo plaster groups, respectively (p = 0.0398). Drug-related adverse events occurred in 13.6% of patients

  17. Long-term erosion rate measurements in gypsum caves of Sorbas (SE Spain) by the Micro-Erosion Meter method

    Science.gov (United States)

    Sanna, Laura; De Waele, Jo; Calaforra, José Maria; Forti, Paolo

    2015-01-01

    The present work deals with the results of long-term micro-erosion measurements in the most important gypsum cave of Spain, the Cueva del Agua (Sorbas, Almeria, SE Spain). Nineteen MEM stations were positioned in 1992 in a wide range of morphological and environmental settings (gypsum floors and walls, carbonate speleothems, dry conduits and vadose passages) inside and outside the cave, on gypsum and carbonate bedrocks and exposed to variable degree of humidity, different air flow and hydrodynamic conditions. Four different sets of stations have been investigated: (1) the main cave entrance (Las Viñicas spring); (2) the main river passage; (3) the abandoned Laboratory tunnel; and (4) the external gypsum surface. Data over a period of about 18 years are available. The average lowering rates vary from 0.014 to 0.016 mm yr- 1 near the main entrance and in the Laboratory tunnel, to 0.022 mm - 1 on gypsum floors and 0.028 mm yr- 1 on carbonate flowstones. The denudation data from the external gypsum stations are quite regular with a rate of 0.170 mm yr- 1. The observations allowed the collecting of important information concerning the feeding of the karst aquifer not only by infiltrating rainwater, but under present climate conditions also by water condensation of moist air flow. This contribution to the overall karst processes in the Cueva del Agua basin represents over 20% of the total chemical dissolution of the karst area and more than 50% of the speleogenetically removed gypsum in the cave system, thus representing all but a secondary role in speleogenesis. Condensation-corrosion is most active along the medium walls, being slower at the roof and almost absent close to the floor. This creates typical corrosion morphologies such as cupola, while gypsum flowers develop where evaporation dominates. This approach also shows quantitatively the morphological implications of condensation-corrosion processes in gypsum karst systems in arid zones, responsible for an

  18. Visualization of the structural changes in plywood and gypsum board during the growth of Chaetomium globosum and Stachybotrys chartarum.

    Science.gov (United States)

    Lewinska, Anna M; Hoof, Jakob B; Peuhkuri, Ruut H; Rode, Carsten; Lilje, Osu; Foley, Matthew; Trimby, Patrick; Andersen, Birgitte

    2016-10-01

    Fungal growth in indoor environments is associated with many negative health effects. Many studies focus on brown- and white-rot fungi and their effect on wood, but there is none that reveals the influence of soft-rot fungi, such as Stachybotrys spp. and Chaetomium spp., on the structure of building materials such as plywood and gypsum wallboard. This study focuses on using micro-computed tomography (microCT) to investigate changes of the structure of plywood and gypsum wallboard during fungal degradation by S. chartarum and C. globosum. Changes in the materials as a result of dampness and fungal growth were determined by measuring porosity and pore shape via microCT. The results show that the composition of the building material influenced the level of penetration by fungi as shown by scanning electron microscopy (SEM). Plywood appeared to be the most affected, with the penetration of moisture and fungi throughout the whole thickness of the sample. Conversely, fungi grew only on the top cardboard in the gypsum wallboard and they did not have significant influence on the gypsum wallboard structure. The majority of the observed changes in gypsum wallboard occurred due to moisture. This paper suggests that the mycelium distribution within building materials and the structural changes, caused by dampness and fungal growth, depend on the type of the material.

  19. 常压盐溶液脱硫石膏转化生成α-半水石膏%Transformation of Flue-Gas-Desulfurization Gypsum to α-Hemihydrated Gypsum in Salt Solution at Atmospheric Pressure

    Institute of Scientific and Technical Information of China (English)

    吴晓琴; 童仕唐; 官宝红; 吴忠标

    2011-01-01

    Direct phase transformation of flue gas desulfurization gypsum in hot salt solution at atmospheric pressure was investigated. The effects of temperature, salt species, salt concentration, solids content, pH and modifier were examined. The crystals obtained under different conditions and solubility of calcium sulfate in contact with solid gypsum were also determined. α-Calcium sulfate hemihydrate crystals of stubby columnar shape and regular pentahedral sides were obtained under the following conditions: salt concentration 20%-30%, operation temperature 95-100 ℃, solids mass content in the slurry 10%-30% and neutral pH. Thermodynamic analysis revealed that phase transformation of calcium sulfate dihydrate to α-calcium suffate hemihydrate occurs because of the difference in solubilities between the two solid gypsum phases in this system.

  20. Climatic control on the growth of gigantic gypsum crystals within hypogenic caves (Naica mine, Mexico)?

    Science.gov (United States)

    Garofalo, Paolo S.; Fricker, Mattias B.; Günther, Detlef; Forti, Paolo; Mercuri, Anna-Maria; Loreti, Mara; Capaccioni, Bruno

    2010-01-01

    Three hypogenic caves within the Naica mine of Mexico ( Cueva de los Cristales — CLC, Ojo de la Reina — OR, and Cueva de las Velas — CLV) host spectacular gypsum crystals up to 11 m in length. These caves are close to another shallow cave of the area ( Cueva de las Espadas — CLE), with which they cover a 160 m-deep vertical section of the local drainage basin. Similar to other hypogenic caves, all these caves lack a direct connection with the land surface and should be unrelated with climate. A record of multi-technique fluid inclusion data and pollen spectra from cave and mine gypsum indicates surprisingly that climatic changes occurring at Naica could have controlled fluid composition in these caves, and hence crystal growth. Microthermometry and LA-ICP-Mass Spectrometry of fluid inclusions indicate that the shallow, chemically peculiar, saline fluid (up to 7.7 eq. wt.%NaCl) of CLE could have formed from evaporation, during a dry and hot climatic period. The fluid of the deep caves was instead of low salinity (˜ 3.5 eq. wt.% NaCl) and chemically homogeneous, and was poorly affected by evaporation. We propose that mixing of these two fluids, generated at different depths of the Naica drainage basin, determined the stable supersaturation conditions for the gigantic gypsum crystals to grow. Fluid mixing was controlled by the hydraulic communication between CLE and the other deep caves, and must have taken place during cycles of warm-dry and fresh-wet climatic periods, which are known to have occurred in the region. Pollen grains from a 35 ka-old gypsum crystal of CLC corresponds to a fairly homogenous catchment basin made of a mixed broadleaf wet forest, which suggests precipitation during a fresh-wet climatic period and confirms our interpretation of the fluid inclusion data. The unusual combination of geological and geochemical factors of Naica suggests that other hypogenic caves found elsewhere may not host similar crystals. However, this work shows that

  1. Utilization of the gypsum from a wet limestone flue gas desulfurization process

    Science.gov (United States)

    Chou, I.-Ming; Patel, V.; Lytle, J.M.; Chou, S.J.; Carty, R.H.

    1999-01-01

    The authors have been developing a process which converts FGD-gypsum to ammonium sulfate fertilizer with precipitated calcium carbonate as a by-product during the conversion. Preliminary cost estimates suggest that the process is economically feasible when ammonium sulfate crystals are produced in a granular size (1.2 to 3.3 mm), instead of a powder form. However, if additional revenue from the sale of the PCC for higher-value commercial application is applicable, this could further improve the economics of the process. Ammonium sulfate is known to be an excellent source of nitrogen and sulfur in fertilizer for corn and wheat production. It was not known what impurities might co-exist in ammonium sulfate derived from scrubber gypsum. Before the product could be recommended for use on farm land, the impurities and their impact on soil productivity had to be assessed. The objectives of this phase of the study were to evaluate the chemical properties of ammonium sulfate made from the FGD-gypsum, to estimate its effects on soil productivity, and to survey the marketability of the two products. The results of this phase of the study indicated that the impurities in the ammonium sulfate produced would not impose any practical limitations on its use at application levels used by farmers. The market survey showed that the sale price of solid ammonium sulfate fertilizer increased significantly from 1974 at $110/ton to 1998 at $187/ton. Utilities currently pay $16 to $20/ton for the calcium carbonate they use in their flue gas scrubber system. The industries making animal-feed grade calcium supplement pay $30/ton to $67/m-ton for their source of calcium carbonate. Paper, paint, and plastic industries pay as much as $200 to $300/ton for their calcium carbonate filers. The increased sale price of solid ammonium sulfate fertilizer and the possible additional revenue from the sale of the PCC by-product could further improve the economics of producing ammonium sulfate from FGD-gypsum.

  2. Perimbangan Gypsum Bonded Investment terhadap Penysutan Logam Paduan Emas pada Saat Pengecoran

    Directory of Open Access Journals (Sweden)

    Ronnie Rusli

    2015-10-01

    Full Text Available Gypsum bonded investment is usually used for dental gold alloys casting procedure. Casting alloys shrink during solidified from melting temperature to room temperature. In order to obtain an accurate restoration, the shrinkage of the alloy should be compensated by the expansion of the investment at the time of casting procedure. Ideally, the shrinkage of the alloy is equal to the expansion of the investment. However, no investment material fulfills this ideal condition properly. In this paper, how the investment material compensated the shrinkage of the casting alloys will be described briefly.

  3. Glomalin Production and Microbial Activity in Soils Impacted by Gypsum Mining in a Brazilian Semiarid Area

    Directory of Open Access Journals (Sweden)

    Adalia C.E.S. Mergulhao

    2010-01-01

    Full Text Available Problem statement: Mining activities involve the removal of the vegetal cover and the soil organic layer, causing a severe environmental impact. In Northeast Brazil, 40% of the worlds crude gypsum is found in a semiarid area, making this region responsible for 95% of the gypsum demand in the national market. Although economically important, this activity is harmful to the environment. Studies of soil microbiological and biochemical attributes can help in the identification of the limitations of impacted ecosystems, providing data to define strategies for sustainability of such environments. Approach: To evaluate and compare the biological state of preserved and mining degraded semiarid soils, a native preserved area and areas impacted by gypsum mining were selected at the Araripina Experimental Station, located in the semiarid region of Pernambuco State, Northeast Brazil. The four sampling areas included: (1 A native, preserved �caatinga� area with spine bearing trees and shrubs and some characteristic xerophytic plants (AN; (2 An area surrounding the mine, presenting the same type of vegetation although already degraded (AM; (3 A waste deposit area (AR; (4 Interface area between the waste deposit and a mining degraded area (AI. Samples were taken in each area (1000 m2 during two periods: wet (December/2003, Rainfall = 28.7 mm and dry (September/2004, Rainfall = 1.3 mm. Results: Fluorescein diacetate hydrolysis values, microbial biomass C and basal respiration were higher in the preserved caatinga than in the impacted areas. The gypsum mining activity reduced the concentration of easily extractable glomalin in relation to the native caatinga area in both sampling periods. Higher deposits of total glomalin also occurred in the native area, however, mainly during the wet period. Conclusion: The mining activity produced a negative impact on the soil microbiota, reducing the total enzymatic activity. The microbial

  4. Multi-technique investigation of Roman decorated plasters from Villa dei Quintili (Rome, Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Crupi, Vincenza, E-mail: vcrupi@unime.it [Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale Ferdinando Stagno d’Alcontres 31, 98166 Messina (Italy); Galli, Giuliana [Soprintendenza Speciale per i Beni Archeologici di Roma, Villa dei Quintili, via Appia Nuova 1092, 00197 Roma (Italy); La Russa, Mauro Francesco [Dipartimento di Biologia, Ecologia e Scienze della Terra (DiBEST), Università degli Studi della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende (Cs) (Italy); Longo, Francesca; Maisano, Giacomo; Majolino, Domenico [Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale Ferdinando Stagno d’Alcontres 31, 98166 Messina (Italy); Malagodi, Marco [Dipartimento di Chimica, Università di Pavia, Via Taramelli 12, 27100 Pavia (Italy); Pezzino, Antonino [Dipartimento di Scienze Biologiche, Geologiche e Ambientali—Sezione di Scienze della Terra, Università degli Studi di Catania, Corso Italia 57, 95129 Catania (Italy); Ricca, Michela [Dipartimento di Biologia, Ecologia e Scienze della Terra (DiBEST), Università degli Studi della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende (Cs) (Italy); Rossi, Barbara [Elettra – Sincrotrone Trieste, Strada Statale 14 km 163.5, Area Science 70 Park, 34149 Trieste (Italy); Dipartimento di Fisica, Università degli Studi di Trento, via Sommarive 14, 38123 Povo, Trento (Italy); Ruffolo, Silvestro Antonio [Dipartimento di Biologia, Ecologia e Scienze della Terra (DiBEST), Università degli Studi della Calabria, Via Pietro Bucci, 87036 Arcavacata di Rende (Cs) (Italy); and others

    2015-09-15

    Highlights: • A multi-technique non-invasive approach using portable instrumentation is proposed. • Due to the use of different techniques, pigments of same color were distinguished. • The experimental results shed light on the used painting methodologies. • The experimental results provided useful information for restoration processes. • This work is the first study of coloring matter used in Villa dei Quintili. - Abstract: In the present study, we investigated by the joint use of portable instrumentations, namely a handheld X-ray fluorescence (XRF) analyser and a portable Raman spectrometer, the painted surface of plasters withdrawn from different areas of an important Roman monumental complex, known as Villa dei Quintili (Rome, Italy), dated back to the first half of the 2nd century a.C. XRF and Raman measurements contributed to the identification of the pigments through the elemental and molecular composition, respectively. In particular, the multi-technique non-invasive approach proved to be crucial for distinguishing two different reddish pigments. In order to confirm and integrate XRF and Raman results, two micro-destructive laboratory methods, namely optical microscopy (OM) and scanning electron microscopy coupled with energy-dispersive X-ray spectrometry (SEM-EDS), were also employed on the same samples. All the experimental results shed light on the material characterizing the painted surface layer and the painting methodologies, providing in principle useful information for proper restoration processes. It is worth underlining that this experimental investigation takes part of a recent multidisciplinary study performed on this impressive archaeological site, aimed to characterize for the first time the monumental complex from an archaeometric point of view.

  5. Laser cleaning experiences on sculptures' materials: terracotta, plaster, wood, and wax

    Science.gov (United States)

    Pelosi, Claudia; Fodaro, D.; Sforzini, Livia; Lo Monaco, Angela

    2013-11-01

    The focus of this paper is to show the work experiences with laser cleaning on sculptures made of terracotta, plaster, wood and wax. These materials exhibit peculiar features that often prevent the use of traditional cleaning procedures to remove the surface dirt, soot or carbonaceous deposits and other materials coming from environment or ancient conservative interventions. To overcome the difficulties in the cleaning of the above mentioned materials, laser technology was tested. The laser irradiation and cleaning tests were carried out with a Q-switched Nd:YAG system under the following conditions: wavelength 1064 nm and 532 nm; energy 4-28 mJ; pulse duration 10 ns; spot diameter 2-8 mm; frequency 5 Hz. The irradiated surfaces were analyzed before and after the laser tests, with the aid of a video microscope and a reflectance spectrophotometer, in order to evaluate the morphology and colour changes of the surfaces. Before starting with the cleaning intervention, some diagnostic analysis was performed on the sculptures in order to obtain the identification of the original materials and of the surface deposits. Concerning this, Fourier Transform Infrared spectroscopy, X-ray fluorescence spectroscopy, and internal micro stratigraphic analysis were performed. This research demonstrated that the laser cleaning is an effective method to remove the surface deposits preserving the original patina of the sculptures and the opacity of the wax. The results gathered in this work encourage to continue the research in order to better understand the interactions between the laser beam and the surfaces and to find the most appropriate laser conditions to clean the sculptures.

  6. Early mobilisation versus plaster immobilisation of simple elbow dislocations: results of the FuncSiE multicentre randomised clinical trial.

    Science.gov (United States)

    Iordens, Gijs I T; Van Lieshout, Esther M M; Schep, Niels W L; De Haan, Jeroen; Tuinebreijer, Wim E; Eygendaal, Denise; Van Beeck, Ed; Patka, Peter; Verhofstad, Michael H J; Den Hartog, Dennis

    2017-03-01

    To compare outcome of early mobilisation and plaster immobilisation in patients with a simple elbow dislocation. We hypothesised that early mobilisation would result in earlier functional recovery. From August 2009 to September 2012, 100 adult patients with a simple elbow dislocation were enrolled in this multicentre randomised controlled trial. Patients were randomised to early mobilisation (n=48) or 3 weeks plaster immobilisation (n=52). Primary outcome measure was the Quick Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) score. Secondary outcomes were the Oxford Elbow Score, Mayo Elbow Performance Index, pain, range of motion, complications and activity resumption. Patients were followed for 1 year. Quick-DASH scores at 1 year were 4.0 (95% CI 0.9 to 7.1) points in the early mobilisation group versus 4.2 (95% CI 1.2 to 7.2) in the plaster immobilisation group. At 6 weeks, early mobilised patients reported less disability (Quick-DASH 12 (95% CI 9 to 15) points vs 19 (95% CI 16 to 22); p<0.05) and had a larger arc of flexion and extension (121° (95% CI 115° to 127°) vs 102° (95% CI 96° to 108°); p<0.05). Patients returned to work sooner after early mobilisation (10 vs 18 days; p=0.020). Complications occurred in 12 patients; this was unrelated to treatment. No recurrent dislocations occurred. Early active mobilisation is a safe and effective treatment for simple elbow dislocations. Patients recovered faster and returned to work earlier without increasing the complication rate. No evidence was found supporting treatment benefit at 1 year. NTR 2025. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  7. Building a diagnostic algorithm on localized neuropathic pain (LNP) and targeted topical treatment: focus on 5% lidocaine-medicated plaster

    Science.gov (United States)

    Casale, Roberto; Mattia, Consalvo

    2014-01-01

    Within the broad definition of neuropathic pain, the refinement of clinical diagnostic procedures has led to the introduction of the concept of localized neuropathic pain (LNP). It is characterized by consistent and circumscribed area(s) of maximum pain, which are associated with negative or positive sensory signs and/or spontaneous symptoms typical of neuropathic pain. This description outlines the clinical features (currently lacking in guidelines and treatment recommendations) in patients for whom topical targeted treatment with 5% lidocaine-medicated plaster is suggested as first-line therapy. Few epidemiologic data are present in the literature but it is generally estimated that about 60% of neuropathic pain conditions are localized, and therefore identifiable as LNP. A mandatory clinical criterion for the diagnosis of LNP is that signs and symptoms must be present in a clearly identified and defined area(s). Cartographic recordings can help to define each area and to assess variations. The diagnosis of LNP relies on careful neurological examination more than on pain questionnaires, but it is recognized that they can be extremely useful for recording the symptom profiles and establishing a more targeted treatment. The most widely studied frequent/relevant clinical presentations of LNP are postherpetic neuralgia, diabetic neuropathy, and neuropathic postoperative pain. They successfully respond to treatment with 5% lidocaine-medicated plaster with equal if not better pain control but with fewer side effects versus conventional systemic treatments. Generally, the more localized the pain (ie, the area of an A4 sheet of paper) the better the results of topical treatment. This paper proposes an easy-to-understand algorithm to identify patients with LNP and to guide targeted topical treatments with 5% lidocaine medicated plaster. PMID:24790451

  8. Solid phase microextraction, sand flies, oviposition pheromones, plaster of Paris and siloxanes-What is in common?

    Science.gov (United States)

    Goulart, Thais Marchi; Tosta, Christiann Davis; Machado, Vicente Estevam; da Rocha Silva, Flávia Benini; de Castro, Camila Feitosa; Ortiz, Dennys Ghenry Samillan; Oliveira, Wanderson Henrique Cruz; Pinto, Mara Cristina

    2017-04-01

    Sand flies are natural hosts of various microorganisms. Due to their epidemiological importance, sand fly colonies are kept in laboratories to be studied in terms of their biology and vector/host/parasite interactions. In order to investigate the presence of oviposition pheromones in Nyssomyia neivai, experiments using Solid Phase Microextraction (SPME) were performed. However, siloxanes which is an external class of contamination, present in breeding containers made by plaster used to maintain sand flies in colonies, may be hindered the experiments. Published by Elsevier B.V.

  9. Characterization of the Minimum Effective Layer of Thermal Insulation Material Tow-plaster from the Method of Thermal Impedance

    Directory of Open Access Journals (Sweden)

    M.S. Ould Brahim

    2011-04-01

    Full Text Available Our objective in this study is to determine the effective thermal insulating layer of a composite towplaster. The characterization of thermal insulating material is proposed from the study of the thermal impedance in dynamic two-dimensional frequency. Thermo physical properties of the material tow-plaster are determined from the study of the thermal impedance. Nyquist representations have introduced an interpretation of certain phenomena of heat transfer from the series and shunt resistors. The overall coefficient of heat exchange is determined from the Bode plots. A method for determining the thermal conductivity is proposed.

  10. A win/win solution for FGD-gypsum: researches discover beneficial applications for by-product in agriculture

    Energy Technology Data Exchange (ETDEWEB)

    Ramsier, C.; Norton, D. [AG Spectrum Co. (United States)

    2006-07-01

    Research at the Ohio State University and the USDA-ARS National Soil Erosion Research Lab at Purdue University has uncovered some viable new reasons for using FGD-gypsum as a regular part of production agriculture. Work has centered on FGD gypsum or calcium sulfite and to a much lesser extent on fly ash. Researchers have found three agronomically valuable functions of these materials. First, and most obvious, is the fertilizer value of these materials. Gypsum applications to the soil surface provide the rainfall with an alternative source of electrolyte which prevents soil crushing, thus keeping the soil open and permeable to rainwater and air. Gypsum is more effective than liming materials atremediation of sub-soil acidity by detoxifying the excess exchangeable aluminium, which causes low pH. One proven way to sequester carbon is to fix it as organic matter in soil. 90% of the carbon in roots is converted to soil organic matter, whereas 90% of surface residue is oxide and the carbon returned to the atmosphere. Therefore, more carbon is sequestered by increasing root growth. Improved soil water management also reduces nitrous oxide emissions from soils. The utility's world is improved since the highest quality and lowest cost material is generated by an emission control scrubber as FGD-gypsum. There are more than 175 million crop acres in the US alone. Each acre would require 0.5 ton per year to prevent surface sealing. This means that the potential for FGD-gypsum use is more than 80 million tons per year. 4 photos.

  11. Biogeochemical oxidation of calcium sulfite hemihydrate to gypsum in flue gas desulfurization byproduct using sulfur-oxidizing bacteria.

    Science.gov (United States)

    Graves, Duane; Smith, Jacques J; Chen, Linxi; Kreinberg, Allison; Wallace, Brianna; White, Robby

    2017-10-01

    Flue gas desulfurization (FGD) is a well-established air treatment technology for coal and oil combustion gases that commonly uses lime or pulverized limestone aqueous slurries to precipitate sulfur dioxide (SO2) as crystalline calcium salts. Under forced oxidation (excess oxygen) conditions, FGD byproduct contains almost entirely (>92%) gypsum (CaSO4·2H2O), a useful and marketable commodity. In contrast, FGD byproduct formed in oxygen deficient oxidation systems contains a high percentage of hannebachite (CaSO3·0.5H2O) to yield a material with no commercial value, poor dewatering characteristics, and that is typically disposed in landfills. Hannebachite in FGD byproduct can be chemically converted to gypsum; however, the conditions that support rapid formation of gypsum require large quantities of acids or oxidizers. This work describes a novel, patent pending application of microbial physiology where a natural consortium of sulfur-oxidizing bacteria (SOB) was used to convert hannebachite-enriched FGD byproduct into a commercially valuable, gypsum-enriched product (US Patent Assignment 503373611). To optimize the conversion of hannebachite into gypsum, physiological studies on the SOB were performed to define their growth characteristics. The SOB were found to be aerobic, mesophilic, neutrophilic, and dependent on a ready supply of ammonia. They were capable of converting hannebachite to gypsum at a rate of approximately five percent per day when the culture was applied to a 20 percent FGD byproduct slurry and SOB growth medium. 16S rDNA sequencing revealed that the SOB consortium contained a variety of different bacterial genera including both SOB and sulfate-reducing bacteria. Halothiobacillus, Thiovirga and Thiomonas were the dominant sulfur-oxidizing genera. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Analysis of wall plasters and natural sediments from the Neolithic town of Çatalhöyük (Turkey) by a range of analytical techniques

    Science.gov (United States)

    Anderson, Emma; Almond, Matthew J.; Matthews, Wendy

    2014-12-01

    Wall plaster sequences from the Neolithic town of Çatalhöyük have been analysed and compared to three types of natural sediment found in the vicinity of the site, using a range of analytical techniques. Block samples containing the plaster sequences were removed from the walls of several different buildings on the East Mound. Sub-samples were examined by IR spectroscopy, X-ray diffraction and X-ray fluorescence to determine the overall mineralogical and elemental composition, whilst thin sections were studied using optical polarising microscopy, IR Microscopy and Environmental Scanning Electron Microscopy with Energy Dispersive X-ray analysis. The results of this study have shown that there are two types of wall plaster found in the sequences and that the sediments used to produce these were obtained from at least two distinct sources. In particular, the presence of clay, calcite and magnesian calcite in the foundation plasters suggested that these were prepared predominantly from a marl source. On the other hand, the finishing plasters were found to contain dolomite with a small amount of clay and no calcite, revealing that softlime was used in their preparation. Whilst marl is located directly below and around Çatalhöyük, the nearest source of softlime is 6.5 km away, an indication that the latter was important to the Neolithic people, possibly due to the whiter colour (5Y 8/1) of this sediment. Furthermore, the same two plaster types were found on each wall of Building 49, the main building studied in this research, and in all five buildings investigated, suggesting that the use of these sources was an established practice for the inhabitants of several different households across the site.

  13. Reduction of painful area as new possible therapeutic target in post-herpetic neuropathic pain treated with 5% lidocaine medicated plaster: a case series.

    Science.gov (United States)

    Casale, Roberto; Di Matteo, Maria; Minella, Cristina E; Fanelli, Guido; Allegri, Massimo

    2014-01-01

    Post-herpetic neuralgia (PHN) is neuropathic pain persisting after an acute episode of herpes zoster, and is associated with severe pain and sensory abnormalities that adversely affect the patient's quality of life and increase health care costs. Up to 83% of patients with PHN describe localized neuropathic pain, defined as "a type of neuropathic pain characterized by consistent and circumscribed area(s) of maximum pain". Topical treatments have been suggested as a first-line treatment for localized neuropathic pain. Use of 5% lidocaine medicated plaster could reduce abnormal nervous peripheral discharge and via the plaster could have a "protective" function in the affected area. It has been suggested that use of this plaster could reduce pain as well as the size of the painful area. To evaluate this possible outcome, we retrospectively reviewed eight patients with PHN, treated using 5% lidocaine medicated plaster. During a follow-up period of 3 months, we observed good pain relief, which was associated with a 46% reduction in size of the painful area after one month (from 236.38±140.34 cm(2) to 128.80±95.7 cm(2)) and a 66% reduction after 3 months (81.38±59.19 cm(2)). Our study cohort was composed mainly of elderly patients taking multiple drugs to treat comorbidities, who have a high risk of drug-drug interactions. Such patients benefit greatly from topical treatment of PHN. Our observations confirm the effectiveness of lidocaine plasters in the treatment of PHN, indicating that 5% lidocaine medicated plaster could reduce the size of the painful area. This last observation has to be confirmed and the mechanisms clarified in appropriate larger randomized controlled trials.

  14. Effect of burnout temperature on strength of gypsum-bonded investments.

    Science.gov (United States)

    Luk, W K; Darvell, B W

    2003-09-01

    To investigate the variation of the strength of gypsum-bonded dental investments with burnout temperature. The disc-rupture test was employed at burnout temperatures ranging from 450 to 800 degrees C for four products (Beauty Cast, Cristobalite, Novocast (all WhipMix) and Deguvest California (Degussa)). In this test, an investment disc is created inside an investment mold such that it forms a diaphragm across the mold space, being an integral part of the mold. Copper was cast into molds of this type, and whether the disc had ruptured or not was determined by inspection when cold. The amount of copper cast in successive tests was varied in staircase fashion up and down depending on whether the disc survived or failed. The strength of the investment was represented by the 50% point of the transition from survival to rupture. The strength of gypsum-bonded investment is temperature sensitive, there being marked differences between the products tested. Overall, the strength ranking (temperature range average/MPa) was: Cristobalite (10.1)>Beauty Cast (7.8)>Novocast (5.1)>Deguvest California (3.4). The strength ranking at high temperatures differs from that known for the room temperature values. The use by manufacturers of room-temperature strength data conveys no information about high temperature behavior. Investment properties should be optimized by reference to behavior under casting conditions.

  15. Potential Agricultural Uses of Flue Gas Desulfurization Gypsum in the Northern Great Plains

    Energy Technology Data Exchange (ETDEWEB)

    DeSutter, T.M.; Cihacek, L.J. [North Dakota State University, Fargo, ND (United States). Department of Soil Science

    2009-07-15

    Flue gas desulfurization gypsum (FGDG) is a byproduct from the combustion of coal for electrical energy production. Currently, FGDG is being produced by 15 electrical generating stations in Alabama, Florida, Indiana, Iowa, Kentucky, Ohio, North Carolina, South Carolina, Tennessee, Texas, and Wisconsin. Much of this byproduct is used in the manufacturing of wallboard. The National Network for Use of FGDG in Agriculture was initiated to explore alternative uses of this byproduct. In the northern Great Plains (North Dakota, South Dakota, and Montana), FGDG has the potential to be used as a Ca or S fertilizer, as an acid soil ameliorant, and for reclaiming or mitigating sodium-affected soils. Greater than 1.4 million Mg of FGDG could initially be used in these states for these purposes. Flue gas desulfurization gypsum can be an agriculturally important resource for helping to increase the usefulness of problem soils and to increase crop and rangeland production. Conducting beneficial use audits would increase the public awareness of this product and help identify to coal combustion electrical generating stations the agriculturally beneficial outlets for this byproduct.

  16. AN INNOVATIVE INTEGRATED APPROACH TO MINIMIZING GYPSUM AND PYRITE WASTES BY CONVERSION TO MARKETABLE PRODUCTS

    Energy Technology Data Exchange (ETDEWEB)

    Daniel Tao

    2000-06-27

    The objective of this research program is to develop a novel integrated process to eliminate millions of tons of gypsum and pyrite wastes generated annually by the U.S. energy industries and reduce the emission of millions of tons of greenhouse gas carbon dioxide. This was accomplished by converting gypsum and pyrite wastes to marketable products such as lime, direct reduced iron (DRI), and sulfur products and obviating the need to calcine millions of tons of limestone for use in utility scrubbers. Specific objectives included: (1) Develop a novel, integrated process for utilizing two major wastes generated by mining and energy industries to produce lime for recycling and other marketable products. (2) Study individual chemical reactions involved in pyrite decomposition, DRI production, and Muller-Kuhne process for lime regeneration to determine optimum process variables such as temperature, time, and reactant composition. (3) Investigate techniques for effective concentration of pyrite from tailing waste and methods for effective separation of DRI from calcium sulfide.

  17. The production of hydroxyapatite prototypes from solid bodies of Gypsum/Polyvinyl Alcohol composites

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Amanda Alves; Ferraz, Andrea de Vasconcelos; Dantas, Alan Christie; Olivier, Nelson Cardenas, E-mail: andrea.ferraz@univasf.edu.br [Universidade Federal do Vale do Sao Francisco (UNIVASF), Juazeiro, BA (Brazil)

    2014-08-15

    Prototypes of porous hydroxyapatite (HAp) were produced from Gypsum/PVA composite, using a mass proportion of 15% polymer. The material was obtained by means of chemical conversion in (NH{sub 4}){sub 2}HPO{sub 4} 0.5 mol.L{sup -1} solution and NH{sub 4}OH 6.0 mol.L{sup -1} alkaline medium for pH control, maintained between 6.0 and 9.0. The reaction occurred at a temperature of 100°C at different test times. The obtained HAp was characterized by several techniques, such as FTIR, which identified the SO{sub 4}{sup 2-} groups characteristic for the Gypsum block, and the PO{sub 4}{sup 2-} groups that are attributed to the biomaterial HAp, besides XRD and SEM, which made it possible to confirm a successful conversion of the material. Tests for mechanical resistance to compression (σ{sub c}) were carried out for both materials as well. (author)

  18. Breakdown development in cover beds, and landscape features induced by intrastratal gypsum karst

    Directory of Open Access Journals (Sweden)

    Andrejchuk V.

    1996-01-01

    Full Text Available Intrastratal karst is by far the predominant gypsum karst type. Its development may begin in deep-seated settings within rocks already buried by younger strata, and it proceeds increasingly rapidly as uplift brings gypsum sequences into progressively shallower positions. Such development commonly occurs under confined (artesian hydrogeological conditions, that subsequently change to open conditions (phreatic-water table-vadose. The general evolutionary line of intrastratal karst is typified by progressive emergence of a sequence into a shallower position, activation of groundwater circulation and development of cave systems within karst units, commencement of gravitational breakdown and its upward propagation through overlying beds, and development of a karst landscape. These processes and phenomena progress through the directed evolution of karst types as follows: deep-seated intrastratal karst (1K to subjacent 1K to entrenched 1K to denuded karst. One of the main characteristics of intrastratal karst is that it induces gravitational breakdown in cover beds. With the aid of processes other then simple breakdown, such effects may propagate upwards and may, or may not, reach the surface, depending upon the thickness and structure of the overburden. A karst landscape evolves when such features reach the surface. This paper considers the conditions and mechanisms of such development.

  19. Investigation of Dynamic Crack Coalescence Using a Gypsum-Like 3D Printing Material

    Science.gov (United States)

    Jiang, Chao; Zhao, Gao-Feng; Zhu, Jianbo; Zhao, Yi-Xin; Shen, Luming

    2016-10-01

    Dynamic crack coalescence attracts great attention in rock mechanics. However, specimen preparation in experimental study is a time-consuming and difficult procedure. In this work, a gypsum-like material by powder bed and inkjet 3D printing technique was applied to produce specimens with preset cracks for split Hopkinson pressure bar (SHPB) test. From micro X-ray CT test, it was found that the 3D printing technique could successfully prepare specimens that contain preset cracks with width of 0.2 mm. Basic mechanical properties of the 3D printing material, i.e., the elastic modulus, the Poisson's ratio, the density, the compressive strength, the indirect tensile strength, and the fracture toughness, were obtained and reported. Unlike 3D printed specimens using polylactic acid, these gypsum-like specimens can produce failure patterns much closer to those observed in classical rock mechanical tests. Finally, the dynamic crack coalescence of the 3D printed specimens with preset cracks were captured using a high-speed camera during SHPB tests. Failure patterns of these 3D printed specimens are similar to the specimens made by Portland cement concrete. Our results indicate that sample preparation by 3D printing is highly competitive due to its quickness in prototyping, precision and flexibility on the geometry, and high material homogeneity.

  20. Experimental Study of Stabilized Soil Utilizing Circulating Fluidized Bed Combustion Desulfurization Ash with Carbide Slag and Desulfurization Gypsum

    OpenAIRE

    2015-01-01

    This paper discusses the feasibility of preparing soil stabilizer which is circulating fluidized bed combustion ash-based, supplemented with carbide slag and desulfurization gypsum, composed entirely of complete industrial wastes. The results show that CFBC ash has better pozzolanic activity than fly ash. When stabilizer total content is 10% and the ratio of CFBC ash : carbide slag : desulfurization gypsum is 7.2 : 1.8 : 1, compressive strength of stabilized soil can reach the maximum of 2.12...

  1. Gypsum-based biomaterials: Evaluation of physical and mechanical properties, cellular effects and its potential as a pulp liner.

    Science.gov (United States)

    Low, Amy; Mohd Yusof, Hamidah; Reza, Fazal; Abdullah Nurul, Asma; Sritharan, Shaminea; Haania Zain Ali, Niswathul; Subhi Azeez, Hasan; Husein, Adam

    2015-01-01

    This in vitro study aimed to evaluate setting time and compressive strength of gypsum-based chitosan biomaterials and its effect on proliferation of stem cells from human exfoliated deciduous teeth (SHED) and alkaline phosphatase (ALP) activity. Pure-GYP was mixed with water (2.5 g: 1.9 mL); Gyp-CHT was prepared with gypsum, chitosan, and water (2.5 g: 0.285 g: 1.9 mL). Cell viability and ALP activity were assessed at different periods. Data were analyzed using SPSS (pbiomaterials for its pulp protective potentialities.

  2. Evaluating the fate of mercury and other metals across the life-cycle stages from the use of FGD gypsum for wallboard production

    Science.gov (United States)

    In 2007, 12.3 million tons of flue gas desulfurization (FGD) gypsum was produced due to air emission controls at coal-fired power plants. With increasing use of wet scrubbers in response to more stringent air pollution control requirements, FGD gypsum production is expected to in...

  3. Efficacy and tolerability of DHEP-heparin plaster in reducing pain in mild-to-moderate muscle contusions: a double-blind, randomized trial.

    Science.gov (United States)

    Hoffmann, Peter; Kopačka, Pavel; Gugliotta, Barbara; Rovati, Stefano

    2012-08-01

    To investigate if the 180-mg diclofenac epolamine and heparin sodium 5600 IU medicated plaster (DHEP-heparin) is more effective for pain reduction in mild-to-moderate contusions than the reference diclofenac epolamine 180 mg plaster (DHEP). This multicenter, multinational, prospective, double-blind versus reference comparator and versus placebo, controlled trial had balanced random assignment in three parallel treatment groups. The DHEP-heparin medicated plaster was compared to the DHEP medicated plaster and a placebo medicated plaster. A total of 331 outpatients, aged ≥18 and ≤65 years, with unilateral mild-to-moderate muscle contusion, pain on standardized movement of ≥50 mm, and superficial hematoma of ≤10 × 14 cm(2) completed the study. Plasters were applied each morning, for ≥20 hours daily for 14 consecutive days. Outcomes were assessed in three visits, over 14 days, plus patients' daily self-assessment. 05DCz/FHp11 - Eudra CT n: 2005-003829-31 Primary efficacy endpoint was mean change from baseline in pain on movement after 3 days of treatment, compared between groups. Secondary efficacy endpoints included mean daily change from baseline in pain on movement during treatment, pain level as assessed at control visits after 7 and 14 days, time (days) to hematoma disappearance based on patients' daily evaluations, rescue medication use, and overall treatment efficacy as judged by both patients and investigators. Pain progressively declined in all groups, more rapidly in DHEP-heparin recipients, compared to DHEP, and in both active treatment groups compared to placebo. Adverse events were recorded in 24 of the 355 (6.7%) exposed patients, and generally resolved without need to interrupt treatment. The DHEP-heparin plaster is superior to the reference DHEP plaster in reducing pain associated with mild-to-moderate muscle contusion. Both active treatments were significantly more effective than placebo, and each showed a comparably favor