Articles de revues : « Bentonite pellet/powder mixture »

1

Darde, Benjamin, Anh Minh Tang, Jean-Michel Pereira, Patrick Dangla, Jean-Noël Roux, Jean Talandier et Minh Ngoc Vu. « Modelling the hydromechanical behaviour of expansive granular mixtures upon hydration ». E3S Web of Conferences 195 (2020) : 02006. http://dx.doi.org/10.1051/e3sconf/202019502006.

Texte intégral

Résumé :

Bentonite pellet-powder mixtures are candidate sealing materials in radioactive waste disposal concepts. The mixture is installed in galleries in dry state as a granular material. The material is progressively hydrated by the pore water of the host rock and becomes homogeneous. Before homogenisation, the granular structure controls the material behaviour. In the present work, a modelling approach able to address particular features of pellet-powder mixtures is introduced. Two domains are considered: i) granular, and ii) homogeneous. The material behaviour before homogenisation is studied through Discrete Element Method (DEM) simulations. Constitutive laws for the granular state are proposed from DEM results. The behaviour of the homogenised material is described by a modified Barcelona Basic Model (BBM). Transition from granular to homogeneous states depends on suction and relative volume fractions of pellets and powder. Swelling pressure tests performed in the laboratory are satisfactorily simulated using this approach.

Styles APA, Harvard, Vancouver, ISO, etc.

2

Yang, Jin-Wen, Yu-Jun Cui et Nadia Mokni. « Investigation of water-retention and uniaxial compression behaviour of MX80 bentonite pellet at various suctions ». E3S Web of Conferences 382 (2023) : 19004. http://dx.doi.org/10.1051/e3sconf/202338219004.

Texte intégral

Résumé :

MX80 bentonite pellet/powder mixture has been regarded as a candidate sealing material in deep geological high-level radioactive waste disposal. As single pellet plays an important role in the global hydromechanical behaviour of the mixture, a series of single pellet compression tests were conducted on cylindershape MX80 bentonite 32-mm pellet after reaching suction equilibrium. The changes in volume and water content during the suction equilibration with the vapour equilibrium technique allowed the water-retention properties to be investigated. X-ray μCT observations were also made on pellets after reaching the target suctions. Results showed that upon drying the water content, void ratio and volumetric strain decreased slightly, but increased significantly upon wetting. Moreover, upon drying the network of cracks presented insignificant change and the cracks were mainly located in the marginal areas of pellet, while on wetting, cracks substantially propagated from the marginal areas to the core of pellet. The uniaxial compression tests on single pellets showed that the axial strain εaxial contributed to the contractancy, while the lateral strain εlateral to the dilatancy. The uniaxial shear strength σa, max, the crack closure (CC) stress σcc, the crack initiation (CI) stress σci, the crack damage (CD) stress σcd and the Young’s modulus E were found to decrease with suction decreasing, evidencing the suction effect through softening and cracking. Because of the combined effect of suction and wetting-induced cracks, the Poisson’s ratios v increased until the suction decreased to 38-25 MPa, and then decreased with further suction decrease. Uniaxial loading closed the horizontal wetting-induced cracks at suctions ≤ 9 MPa, leading to a drop of εlateral before CC.

Styles APA, Harvard, Vancouver, ISO, etc.

3

Alcantara, Arisleidy Mesa, Nadia Mokni, Enrique Romero et Sebastià Olivella. « Modelling of oedometer tests on pellet-powder bentonite mixtures to support mock-up test analysis ». E3S Web of Conferences 195 (2020) : 04004. http://dx.doi.org/10.1051/e3sconf/202019504004.

Texte intégral

Résumé :

Bentonite mixtures of MX-80 (80% of high-density pellets and 20% of bentonite powder on a mass basis) have been recently proposed as a candidate material for sealing deep geological disposals of high-level radioactive waste. A loading/unloading oedometer test at constant water content has been performed on this mixture, which has been modelled using the finite element Code_Bright. The constitutive model used to represent the mechanical response is the Barcelona Expansive Model (BExM), since a multi-modal pore size distribution characterises the pore network of the mixture. During compression at constant water content, an increase in the degree of saturation and a consequent reduction of suction is induced. Consequently, two competing effects occur at different pore-size scales: (a) compression due to mean net stress increase; and (b) expansion on induced suction reduction that mainly affects the micro-porosity level inside aggregates. A sensitivity analysis has been performed to explore these effects, in which the elastic compressibility parameter at the micro-porosity scale for changes in mean effective stress plays an important role.

Styles APA, Harvard, Vancouver, ISO, etc.

4

Molinero Guerra, Agustín, Nadia Mokni, Yu-Jun Cui, Pierre Delage, Anh Minh Tang, Patrick Aimedieu, Frédéric Bernier et Michel Bornert. « Impact of initial structural heterogeneity on long-term swelling behavior of MX80 bentonite pellet/powder mixtures ». Canadian Geotechnical Journal 57, n^o 9 (septembre 2020) : 1404–16. http://dx.doi.org/10.1139/cgj-2018-0301.

Texte intégral

Résumé :

To better understand results of SEALEX in situ tests carried out at Tournemire Underground Research Laboratory, the hydromechanical behavior of a pellet/powder MX80 bentonite mixtures prepared at a dry density of 1.49 Mg/m3 were investigated by means of microfocus X-ray computed tomography (μ-CT) observations and laboratory small scale infiltration tests. Radial and axial swelling pressures as well as relative humidity were monitored while wetting. Two configurations were considered: for the first, a pellet/powder mixture was prepared following a specific protocol to minimize initial structural heterogeneity; the second one was specially designed to study a strong heterogeneous mixture distribution. μ-CT observations performed on the two samples during hydration revealed an apparently homogeneous sample for the first mixture after 100 days of hydration. For the second specimen, several voids were still observed after 40 days of hydration. A comparison was made between the in situ and mock-up tests. It was observed that the evolutions of radial and axial swelling pressures depend on the initial heterogeneous distribution of the mixture. This heterogeneity is due to the different dry density values at the vicinity of the different sensors. The final values of axial swelling pressures were different for both configurations for the same global dry density.

Styles APA, Harvard, Vancouver, ISO, etc.

5

Alcantara, Arisleidy Mesa, Enrique Romero, Nadia Mokni et Sebastià Olivella. « Microstructural and hydro-mechanical behaviour of bentonite pellets and powder mixtures ». E3S Web of Conferences 195 (2020) : 04003. http://dx.doi.org/10.1051/e3sconf/202019504003.

Texte intégral

Résumé :

Binary mixtures of high-density MX-80 bentonite pellets (80%) and bentonite powder (20%) at hygroscopic water content have been recently considered as an alternative engineered barrier system for the long-term disposal of radioactive wastes. These mixtures display a dry density of around 1.49 Mg/m3 on pouring and present components with multi-modal pore size distributions that significantly evolve during the hydro-mechanical paths. To better understand the hydro-mechanical behaviour of this multiple porosity mixture, the contribution initially focuses on describing the initial state, as well as the main microstructural features determined by mercury intrusion porosimetry tests for the mix and each of the components (pellets and powder). Afterwards, hydro-mechanical results of both components and the mixture are presented. The hydraulic results focus on the water retention and water permeability, while the mechanical tests concentrate on the compressibility properties on loading.

Styles APA, Harvard, Vancouver, ISO, etc.

6

Molinero Guerra, Agustín, Yu-Jun Cui, Yong He, Pierre Delage, Nadia Mokni, Anh Minh Tang, Patrick Aimedieu, Michel Bornert et Frédéric Bernier. « Characterization of water retention, compressibility and swelling properties of a pellet/powder bentonite mixture ». Engineering Geology 248 (janvier 2019) : 14–21. http://dx.doi.org/10.1016/j.enggeo.2018.11.005.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

7

Molinero Guerra, Agustín, Yu-Jun Cui, Nadia Mokni, Pierre Delage, Michel Bornert, Patrick Aimedieu, Anh Minh Tang et Frédéric Bernier. « Investigation of the hydro-mechanical behaviour of a pellet/powder MX80 bentonite mixture using an infiltration column ». Engineering Geology 243 (septembre 2018) : 18–25. http://dx.doi.org/10.1016/j.enggeo.2018.06.006.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

8

Imbert, Christophe, et M. Victoria Villar. « Hydro-mechanical response of a bentonite pellets/powder mixture upon infiltration ». Applied Clay Science 32, n^o 3-4 (mai 2006) : 197–209. http://dx.doi.org/10.1016/j.clay.2006.01.005.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

9

Molinero Guerra, Agustín, Patrick Aimedieu, Michel Bornert, Yu-Jun Cui, Anh Minh Tang, Zhao Sun, Nadia Mokni, Pierre Delage et Frédéric Bernier. « Analysis of the structural changes of a pellet/powder bentonite mixture upon wetting by X-ray computed microtomography ». Applied Clay Science 165 (décembre 2018) : 164–69. http://dx.doi.org/10.1016/j.clay.2018.07.043.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

10

Molinero Guerra, Agustín, Nadia Mokni, Pierre Delage, Yu-Jun Cui, Anh Minh Tang, Patrick Aimedieu, Frédéric Bernier et Michel Bornert. « In-depth characterisation of a mixture composed of powder/pellets MX80 bentonite ». Applied Clay Science 135 (janvier 2017) : 538–46. http://dx.doi.org/10.1016/j.clay.2016.10.030.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

11

Mokni, Nadia, Agustín Molinero Guerra, Yu-Jun Cui, Pierre Delage, Patrick Aimedieu, Michel Bornert et Anh Minh Tang. « Modelling the long-term hydro-mechanical behaviour of a bentonite pellet/powder mixture with consideration of initial structural heterogeneities ». Géotechnique 70, n^o 7 (juillet 2020) : 563–80. http://dx.doi.org/10.1680/jgeot.18.p.110.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

12

Mokni, Nadia, Justo Cabrera et Frederic Deleruyelle. « Large scale Vertical SEALing (VSEAL) test : Impact of gas migration on bentonite based vertical seals ». E3S Web of Conferences 382 (2023) : 14005. http://dx.doi.org/10.1051/e3sconf/202338214005.

Texte intégral

Résumé :

The Institute for Radiological protection and Nuclear Safety (IRSN) has launched the VSEAL project to investigate the impact of gas migration on the long-term performance of bentonite based vertical sealing systems. This project relies on in-situ experiments emplaced in IRSN´s Underground ResearchLaboratory (URL) in Tournemire (South France) and small-scale tests conducted in laboratory. The studied material is mixture of MX80 bentonite high density pellets and powder which are being evaluated as possible sealing materials in deep geological repositories. The test is still in progress, but the collected set of data provides already valuable information of the hydro mechanical behavior of Vertical sealing systems during hydration.

Styles APA, Harvard, Vancouver, ISO, etc.

13

Darde, Benjamin, Patrick Dangla, Jean-Noël Roux, Jean-Michel Pereira, Jean Talandier, Minh Ngoc Vu et Anh Minh Tang. « Modelling the behaviour of bentonite pellet-powder mixtures upon hydration from dry granular state to saturated homogeneous state ». Engineering Geology 278 (décembre 2020) : 105847. http://dx.doi.org/10.1016/j.enggeo.2020.105847.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

14

Zheng, Liange, Chun Chang, Sharon Borglin, Sangcheol Yoon, Chunwei Chou, Yuxin Wu et Jens T. Birkholzer. « Bentonite buffer under high temperature : laboratory experiments and coupled process modeling ». Safety of Nuclear Waste Disposal 2 (6 septembre 2023) : 181–82. http://dx.doi.org/10.5194/sand-2-181-2023.

Texte intégral

Résumé :

Abstract. Bentonite buffer in a geological repository will be simultaneously heated from decaying radioactive waste and hydrated from the surrounding host rock, triggering complex and coupled THMC (thermal–hydrological–mechanical–chemical) processes. Understanding the THMC behavior of bentonite-based engineered barrier system (EBS) is key to the evaluation and prediction of its long-term performance. Studies on the THMC process have been focused on conditions under 100 ∘C, as most design concepts impose a thermal limit of 100 ∘C in bentonite. Recently, studies under high-temperature conditions have been conducted to evaluate the possibility of raising the thermal limit and expanding the data/knowledge base to increase the confidence level. In this abstract, we present a series of bench-scale laboratory experiments at high temperatures (up to 200 ∘C) and the corresponding modeling work. Two sets of column tests were conducted, and each set consisted of two test columns: a control column undergoing only hydration (non-heated) and an experiment column experiencing both heating and hydration (heated). During the experiment, frequent X-ray computed tomography (CT) images were collected to provide a 3D visualization of the density distribution and present the spatiotemporal evolution of (1) hydration/dehydration, (2) clay swelling/shrinkage, (3) displacement, and (4) mineral precipitation. The two sets of tests differ with respect to several experimental conditions, such as bentonite type, compacted density and water content, water chemistry, and hydration pressure, but the important difference is that the first set used bentonite powder with a dry density of 1.28 g cm−3, whereas the second set used granulated bentonite (mixture of pellets and powder) with a dry density of 1.45–1.5 g cm−3. In both sets of experiments, a comprehensive post-dismantling characterization of bentonite samples was carried out after the column tests had been running for 1.5 years. Comparing non-heated and heated columns, the temperature gradient led to lower degree of homogenization of bentonite after bentonite became fully saturated; comparing the first and second sets, granulated and powdered bentonite exhibited drastically different hydration behavior. A THM model with a 2D axisymmetric grid system was used to interpret the data from the first set of tests. The model considers the combined impact of saturation, fluid pressure, and porosity change due to swelling/compression on the spatiotemporal distribution of bulk density and movement of the thermocouple modules. Observations from the tests help us understand the early perturbation of bentonite buffer under high temperature, and data from these tests improve the calibration of key constitutive hydrological and mechanical models and, therefore, enhance the modeling capability with respect to calculating the long-term evolution of bentonite buffer.

Styles APA, Harvard, Vancouver, ISO, etc.

15

Mohamad, Noraiham, Nor Nadiah Abdul Hamid, Nor Abidah Abdul Aziz, Jeeferie Abd Razak, Umar Al Amani Azlan, Mohd Fairuz Dimin et Azizah Shaaban. « Potential of Epoxidized Natural Rubber (ENR) as Hydrophobicity Contributor in Chitosan-Urea Fertilizer ». Applied Mechanics and Materials 761 (mai 2015) : 536–41. http://dx.doi.org/10.4028/www.scientific.net/amm.761.536.

Texte intégral

Résumé :

This study is to investigate the potential of ENR to be incorporated with chitosan for slow release urea fertilizer. In this research, mixture of chitosan and epoxidized natural rubber (ENR) was used as binder to take advantage of their biodegradable and polar characteristics, respectively. The effect of mixing formulation to the properties of fertilizer was studied. Firstly, the chitosan and ENR were diluted in toluene with the presence of bentonite as filler. Then, urea powder was mixed and stirred for 20 minutes before left to dry overnight in an oven at 60°C. Water absorption and water retention analysis were carried out on compressed pellets. The increase of ENR loading was observed to contribute to the increase of hydrophobic properties of the fertilizer. The findings were supported by compositional analysis using Fourier Transform Infrared spectroscopy (FTIR).

Styles APA, Harvard, Vancouver, ISO, etc.

16

Gramegna, Liliana, Frédéric Collin, Jean Talandier, Christophe Imbert et Robert Charlier. « Hydro-mechanical behaviour of a pellets based bentonite seal : Numerical modelling of lab scale experiments ». E3S Web of Conferences 195 (2020) : 04009. http://dx.doi.org/10.1051/e3sconf/202019504009.

Texte intégral

Résumé :

In most of the concept designs for nuclear waste disposals, bentonite-based materials are used to seal underground galleries and shafts. In order to assess the safety of such engineered barriers and to provide a good prediction for the material behaviour, a number of experimental campaigns and constitutive models have been developed mainly focusing on bentonite compacted blocks. On the other hand, in recent years, the use of high density bentonite pellets combined with powdered bentonite has also been considered as an interesting alternative. The bentonite pellets mixtures present a prominent initial heterogeneity level as a result of the inter-pellets porosity, which evolves strongly during hydration. This paper aims to present the numerical modelling strategy adopted for a swelling pressure test on pellets mixture carried by CEA (France). Taking advantage of the finite element code LAGAMINE, the Barcelona Basic model is considered for the bentonite mechanical behaviour and the double porosity model proposed by [1] is used for the water retention behaviour and permeability evolution. Given the already-known complexity of the multiphysical and multiscale coupled processes taking place during bentonite-hydration, the obtained numerical results are in good agreement with experimental measurements. Especially, the non-monotonic evolution of the swelling pressure during the hydration phase is well captured by this model, which is always a challenge for this type of problem.

Styles APA, Harvard, Vancouver, ISO, etc.

17

Medved, Igor, Nediljka Gaurina-Međimurec, Borivoje Pašić et Petar Mijić. « Green Approach in Water-Based Drilling Mud Design to Increase Wellbore Stability ». Applied Sciences 12, n^o 11 (25 mai 2022) : 5348. http://dx.doi.org/10.3390/app12115348.

Texte intégral

Résumé :

Wellbore instability is one of the most serious problems that can occur during drilling, mainly during drilling oil or gas wells through rocks that contain a higher proportion of clay, such as shales. To prevent wellbore instability, oil companies apply different approaches to strengthen wellbore walls, and use different shale swelling inhibitors. The aim of this research was to apply a green approach and the concept of the circular economy in mud design, and to determine whether mandarin peel powder, which is a waste material, can be used as an inhibitor of shale swelling. For that purpose, pellets consisting of bentonite and quartz in a 50:50 ratio were prepared using a compactor, and bentonite-based drilling mud (BM) with and without mandarin peel powder in concentrations of 0.5, 1, 1.5 and 2% by volume of water. The swelling of quartz–bentonite pellets after 2 and 24 h in each drilling-mud sample was determined at room temperature and 90 °C using a linear swell meter. On the basis of laboratory research, we concluded that increasing the concentration of mandarin peel powder reduces pellet swelling. By adding mandarin peel powder particles between 0.1 and 0.16 mm to the base mud at a concentration of 2% by volume of water, the following was achieved: 44% reduction in API filtration, 61.54% reduction in PPT filtration, 45% reduction in pellet swelling after 24 h at room temperature, and 48.6% reduction of pellet swelling after 24 h at 90 °C.

Styles APA, Harvard, Vancouver, ISO, etc.

18

Sivrikaya, Osman, et A. I. Arol. « ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING : PART II : EFFECTS ON METALLURGICAL AND CHEMICAL PROPERTIES ». HOLOS 3 (3 juillet 2014) : 104. http://dx.doi.org/10.15628/holos.2014.1759.

Texte intégral

Résumé :

This study was started to find alternative binders to bentonite and to recover the low preheated and fired pellet mechanical strengths of organic binders-bonded pellets. Bentonite is considered as a chemical impurity for pellet chemistry due to acid constituents (SiO2 and Al2O3). Especially addition of silica-alumina bearing binders is detrimental for iron ore concentrate with high acidic content. Organic binders are the most studied binders since they are free in silica. Although they yield pellets with good wet strength; they have found limited application in industry since they fail to give sufficient physical and mechanical strength to preheated and fired pellets. It is investigated that how insufficient preheated and fired pellet strengths can be improved when organic binders are used as binder. The addition of a slag bonding/strength increasing constituent (free in acidic contents) into pellet feed to provide pellet strength with the use of organic binders was proposed. Addition of boron compounds such as colemanite, tincal, borax pentahydrate, boric acid together with organic binders such as CMC, starch, dextrin and some organic based binders, into magnetite and hematite pellet mixture was tested. After determining the addition of boron compounds is beneficial to recover the low pellet physical and mechanical qualities in the first part of this study, in this second part, metallurgical and chemical properties (reducibility - swelling index – microstructure – mineralogy - chemical content) of pellets produced with combined binders (an organic binder plus a boron compound) were presented. The metallurgical and chemical tests results showed that good quality product pellets can be produced with combined binders when compared with the bentonite-bonded pellets. Hence, the suggested combined binders can be used as binder in place of bentonite in iron ore pelletizing without compromising the pellet chemistry.

Styles APA, Harvard, Vancouver, ISO, etc.

19

Suyoko, Muhammad, Kemas Ridhuan et Untung Surya Dharma. « Karakteristik biopelet tempurung kelapa dan serbuk kayu sebagai bahan bakar alternatif ». ARMATUR : Artikel Teknik Mesin & ; Manufaktur 1, n^o 1 (3 avril 2020) : 8–16. http://dx.doi.org/10.24127/armatur.v1i1.185.

Texte intégral

Résumé :

Biomass is a solid waste derived from biological material that can be generated as fuel. Biomass includes plantation, agriculture, household, forest waste and waste from the wood industry, one of the uses of biomass is bio-pellet. Bio-pellet is an alternative type of energy in the form of solid fuel made from biomass raw material with a size smaller than the size of briquettes. In this research, raw materials from teak wood, acacia, and sengon wood powder were used as well as a mixture of coconut shell charcoal with tapioca adhesive. This study aims to determine the bio-pellet estimation analysis, determine the heating value required by the bio pellet in the combustion process, and determine the burning characteristics of the three types of bio pellets. The method used in this study was the process of making bio-pellet with the same treatment on each bio-pellet, variations bio pellet will be made is 50% teak wood powder and 50% coconut shell charcoal powder, 50% acacia wood powder and 50% coconut shell charcoal powder, and 50% sengon wood powder and 50% coconut shell charcoal powder. Each bio pellet uses an adhesive mixture of 5% of the raw material. The stages of the testing process are bio pellet in laboratory tests to determine the value of the composition of the levels of heat, water, ash, flying substances, and bound carbon. The next testing process is the testing process of bio pellet combustion using a bio pellet stove with a process of boiling 10 liters of water, with fire temperature, water temperature, and the remaining fuel measured. All was done at UM Metro 2 campus. The results of bio pellet testing in the laboratory stated that the highest value was in sengon bio pellet with heating value of 5815.19 cal/g, water content of 5.82%, the ash content of 9.77%, levels of flying matter 69.37%, and carbon content bound 19, 41%. For the high heating value of bio pellet burning is 784.92 kcal/hour. Then the best efficiency is the sengon bio- pellet with a value of 55%.

Styles APA, Harvard, Vancouver, ISO, etc.

20

Kushartomo, Widodo, Henny Wiyanto et Daniel Christianto. « INCREASING THE CALCIUM SILICATE HYDRATE AMOUNT IN REACTIVE POWDER CONCRETE USING MARBLE POWDER ». Spektra : Jurnal Fisika dan Aplikasinya 6, n^o 1 (30 avril 2021) : 25–36. http://dx.doi.org/10.21009/spektra.061.04.

Texte intégral

Résumé :

This research aims to make ultra high strength Reactive Powder Concrete (RPC) with marble powder as one of the components. The use of marble powder can increase Calcium Silicate Hydrate (CSH) and the strength of RPC. The research method used to achieve the objectives is experimental and divided into two steps. The first step is the characterization of a marble and micro silica powder mixture. Stoichiometry calculations are performed to determine the composition of the mixture. The test sample is made in the form of pellets consisting of a mixture of marble powder, micro silica, and water. The water content used is at 30% - 50%. Maintenance is carried out by immersion in water with the temperature of 20oC for 27 days and in steam at temperatures 200oC, 250oC, and 300oC with 2 atm pressure for 4 hours. Material characterization is carried out using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The second step in this research is the RPC compressive strength test. The test sample is made in the form of a cube measuring 50 x 50 x 50 mm. This cube is a mixture of water, cement, micro silica, marble powder, sand, and superplasticizer. Material composition is arranged based on the characterization of the sample pellet test, and maintenance of the sample cube test is carried out as in the sample pellet test.

Styles APA, Harvard, Vancouver, ISO, etc.

21

Ma, Guoliang, Huyuan Zhang, Ze Ji et Yu Tan. « Comparison of the swelling pressure of bentonite pellet-contained materials and powder ». Construction and Building Materials 281 (avril 2021) : 122531. http://dx.doi.org/10.1016/j.conbuildmat.2021.122531.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

22

Bernachy-Barbe, Fabien, Nathalie Conil, William Guillot et Jean Talandier. « Observed heterogeneities after hydration of MX-80 bentonite under pellet/powder form ». Applied Clay Science 189 (mai 2020) : 105542. http://dx.doi.org/10.1016/j.clay.2020.105542.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

23

Kukfisz, Bożena. « Analysis of minimum ignition temperature of pellet dust layer and cloud due to adding BC and ABC fire extinguishing powders ». MATEC Web of Conferences 247 (2018) : 00003. http://dx.doi.org/10.1051/matecconf/201824700003.

Texte intégral

Résumé :

The paper describes the impact of adding fire extinguishing powders acting based on oxygen or flame on values of minimum ignition temperatures of the layer and cloud of pellet dust, and as a consequence the impact or lack of impact on values of maximum admissible temperature on external surfaces of electrical appliances working in their atmospheres. Tests were conducted of the minimum ignition temperature of layer and cloud of the agro armakow pellet dust and the agro jesień pellet dust, with and without additives of fire extinguishing powders BC Jet, BC LB2, ABC 90 and Ogniotex 103 at concentrations ranging from 5 to 70% by weight of powder contents in the mixture. Based on obtained test results it has been ascertained that type ABC powders appear to be much more effective than those type BC, because they have a much bigger impact on increasing the minimum ignition temperature of the layer and the cloud of analysed dust types. Adding only 15% of ABC 90 extinguishing powder to the agro jesień pellet has caused an increase in the minimum ignition temperature of dust layer by 80°C. The BC LB2 powder with agro armakow pellet dust has not been found to cause any changes, even at its concentration as high as 70%. The most optimum additive of powder to the biomass dust was 10% by weight of ABC powder in the mixture. At this concentration the highest increase was recorded in the maximum admissible temperature on the outer surface of electrical appliances from 235°C to 273°C.

Styles APA, Harvard, Vancouver, ISO, etc.

24

Fitrianor, Ahmad, et Aqli Mursadin. « PENGARUH KATALIS BENTONIT PADA HASIL VOLUME SYNGAS GASIFIKASI LIMBAH KAYU GALAM DAN BATUBARA KUALITAS RENDAH ». Scientific Journal of Mechanical Engineering Kinematika 4, n^o 2 (16 décembre 2019) : 15–22. http://dx.doi.org/10.20527/sjmekinematika.v4i2.88.

Texte intégral

Résumé :

This study aims to determine and compare the results of the syngas volume generated from variations in mixing of galam wood powder and bentonite catalyst coal. This research was carried out by mixing galam wood powder and coal with a mass of 200g which was given a bentonite catalyst. There were 4 variations of mixing ingredients namely 200g galam wood powder and 0g coal, 180g galam wood powder and 20g coal, 140g galam wood powder and 60g coal, 100g galam wood powder and 100g coal which added 50%, 30% and 10% bentonite catalysts from the mass of material in each variation of the temperature. Material in updraft gasification with a temperature of 500oC for 120 minutes or 2 hours. The results showed that variations with a mixture of 200g of galam wood powder and 0g coal were the ones that produced the most syngas. This was due to the density of galam wood powder which was more tenuous so it was more flammable at temperatures up to 500oC. The amount of bentonite catalyst addition also affects the volume of syngas produced, where the more addition of bentonite catalysts the more syngas volume is produced, this is because bentonite contains Al2O3 which has good heat conductivity so the heating rate is faster, due to the heating rate faster makes the syngas volume produced more for 120 minutes when gasification.

Styles APA, Harvard, Vancouver, ISO, etc.

25

Mollins, L. H., D. I. Stewart et T. W. Cousens. « Predicting the properties of bentonite-sand mixtures ». Clay Minerals 31, n^o 2 (juin 1996) : 243–52. http://dx.doi.org/10.1180/claymin.1996.031.2.10.

Texte intégral

Résumé :

AbstractOne-dimensional swelling tests and hydraulic conductivity tests have been performed at vertical effective stresses up to 450 kPa on Na-bentonite powder and compacted sand/Na-bentonite mixtures (5, 10 and 20% bentonite by weight) to investigate the use of bentonite-improved soils for waste containment. It was found that bentonite powder swells to reach a final state described by a single straight line on a plot of void ratio against the logarithm of vertical effective stress, regardless of preparation technique. Swelling of sand/bentonite mixtures expressed in terms of the clay void ratio show a deviation from bentonite behaviour above a stress which depends on the bentonite content. Hydraulic conductivity data for bentonite and sand/bentonite mixtures indicate an approximately linear relationship between logarithm of hydraulic conductivity and logarithm of void ratio. A design model based on the clay void ratio, and the sand porosity and tortuosity is presented enabling the hydraulic conductivity of a mixture to be estimated.

Styles APA, Harvard, Vancouver, ISO, etc.

26

Chen, Guan Jhou, Weng Sing Hwang, Shih Hsien Liu et Jaw Min Chou. « Investigation on Properties of Bentonite Type in Cold Bonded Pelletization of Flue Dust ». Advanced Materials Research 409 (novembre 2011) : 743–48. http://dx.doi.org/10.4028/www.scientific.net/amr.409.743.

Texte intégral

Résumé :

In the integrated steel mills fabrication processes, the by-product of flue dust and electrostatic precipitator dust were found to be rich with large amounts of iron and carbon content and it could be recycled as a raw material for blast furnaces. In this study, we use the “Cold-bonded Pellet; CBP” technique to prepare the recycling samples for subsequent processing. Therefore, this study investigated under a fixed amount of bentonite added, the choice of different types of bentonite on the powder granulation performance and strength of particle duration effects, bentonite used as a basis for adjustment. The results showed that Bentonite samples of the granulation efficiency increase, relative to its yield and the rate of sticky increase. In general, CBP particle compressive strength increased, duration have increased, and found that curing condition B are large than the A method. In addition, by particle size analysis results show that, bentonite average particle size of 11-12μm have better compressive strength. Comprehensive assessment of granulation and mechanical properties, of which A label in four Bentonite can be preferred.

Styles APA, Harvard, Vancouver, ISO, etc.

27

Liu, Zhang-Rong, Wei-Min Ye, Yu-Jun Cui, He-Hua Zhu, Qiong Wang et Yong-Gui Chen. « Development of swelling pressure for pellet mixture and compacted block of GMZ bentonite ». Construction and Building Materials 301 (septembre 2021) : 124080. http://dx.doi.org/10.1016/j.conbuildmat.2021.124080.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

28

Sellaf, Hamid, et Benamar Balegh. « An Experimental Study on the Effect of Plastic Waste Powder on the Strength Parameters of Tuff and Bentonite Soils Treated with Cement ». Engineering, Technology & ; Applied Science Research 13, n^o 2 (2 avril 2023) : 10322–27. http://dx.doi.org/10.48084/etasr.5580.

Texte intégral

Résumé :

This experimental study investigated the effect of plastic waste powder on the strength and swelling behavior of tuff and bentonite soils treated by cement since the plastic powder is highly compressible and does not absorb much water. This study aimed to improve the tuff and bentonite soils used in construction by adding plastic waste powder in various ratios (5, 10, 20, and 25%) and a low cement content (2.5%). Atterberg limit, swelling consolidation, and loading-unloading tests were performed to determine the optimal composition of the mixture. The results demonstrated that as the plastic powder content increases, the liquid limits, swelling pressure, swelling potentials, and duration to swelling peak decrease. This reduction is particularly notable for the soil with the highest swelling potential. Compression and recompression indices increase significantly with the content of plastic powder due to its high compressibility. The findings suggest that plastic powder with low cement can be utilized as a soil modification reinforcement material, but with a content that shouldn't significantly alter the compressibility of the mixture.

Styles APA, Harvard, Vancouver, ISO, etc.

29

My Nga, Vo Thi. « BENTONITE PILLARED BY MESOPOROUS SILICA AND ITS APPLICATION FOR GASOLINE TREATMENT ». Vietnam Journal of Science and Technology 55, n^o 5B (24 mars 2018) : 164. http://dx.doi.org/10.15625/2525-2518/55/5b/12222.

Texte intégral

Résumé :

Di Linh bentonite was successfully pillared by mesoporous silica and this result had been published in previous reports. The acidity of this material was estimated by modern physico-chemical methods such as IR, TPD-NH3and the material was applied in the field of petrochemical catalysis. The acidity of the material has also been demonstrated by Cumen cracking at low temperatures about 350 °C with benzene conversion of 36.46 % and benzene selectivity of 73.98 %. In addition, the gasoline yield of silica mesoporous material pillared bentonite had got more twice higher than the one when using a mixture of bentonite powder and MCM-41 powder in the cracking Wax. This result confirms that the bond formation between bentonite and mesoporous silica when using one-step method, which increase acidity of the synthesized material.

Styles APA, Harvard, Vancouver, ISO, etc.

30

Liu, Zhulin, Xuegong Bi, Zeping Gao et Yayu Wang. « Preparation and Properties of Agricultural Residuals-Iron Concentrate Pellets ». Advances in Materials Science and Engineering 2017 (2017) : 1–7. http://dx.doi.org/10.1155/2017/9407259.

Texte intégral

Résumé :

In this paper, carbon-containing pellets were prepared by using crop-derived charcoal made from agricultural residuals and iron ore concentrates, and their pelletizing performance and properties were studied. Experimental results showed that the strengths of pellets were related to the particle size of concentrates and the content of moisture, bentonite, and crop-derived charcoal fines in the pelletizing mixture and the temperature of roasting and reduction. That the granularity of raw materials was fine and the bentonite content increased was beneficial to the improvement of pellet strengths. The suitable molar ratio of carbon to oxygen was 1.0 and the proper proportioning ratios of moisture and binder were 8.0% and 6.5%, respectively. The pellet strengths increased accordingly with increasing the reduction temperature, and when the temperature reached 1200°C, accompanied by the fast reduction of iron and the formation of crystal stock, the dropping strength of product pellets was 15 times and the compressive strength was 1650 N; this may be improved by grinding of the concentrate, leading to acceptable strength for the blast furnace.

Styles APA, Harvard, Vancouver, ISO, etc.

31

Mesa-Alcantara, Arisleidy, Enrique Romero et Nadia Mokni. « Gas transport in a binary bentonite mixture used in sealing systems ». E3S Web of Conferences 382 (2023) : 14004. http://dx.doi.org/10.1051/e3sconf/202338214004.

Texte intégral

Résumé :

Binary mixtures composed of 80% of high-density pellets and 20% of granular bentonite at hygroscopic water content are currently considered for use in vertical sealing systems for the deep and longterm disposal of radioactive wastes. By pouring the dry components without compaction, the mixturedisplays a dry density of around 1.49 Mg/m3. However, these sealing systems are subjected to long-term hydrations from the surrounding formations with the possibility of having zones with entrapped and generated gas that makes it challenging to display a homogeneous saturation of the seal. Therefore, gas transport through these bentonite-based sealing materials at different degrees of saturation is a crucial issue. Hence, several oedometer tests have been conducted to evaluate the impact of gas injection on this mixture at different degrees of saturation and constant pouring dry density. These gas injection/dissipation tests were performed at constant vertical stress or constant volume conditions. The results provided the variation of the effective gas permeability at different degrees of saturation and the gas breakthrough pressure aftersaturation. Furthermore, these gas transport results were interpreted with a microstructural study of the mixture focusing on the volumetric filling of the inter-pellet porosity.

Styles APA, Harvard, Vancouver, ISO, etc.

32

Cuevas, Jaime, Miguel Ángel Cabrera, Carlos Fernández, Carlos Mota-Heredia, Raúl Fernández, Elena Torres, María Jesús Turrero et Ana Isabel Ruiz. « Bentonite Powder XRD Quantitative Analysis Using Rietveld Refinement : Revisiting and Updating Bulk Semiquantitative Mineralogical Compositions ». Minerals 12, n^o 6 (17 juin 2022) : 772. http://dx.doi.org/10.3390/min12060772.

Texte intégral

Résumé :

Bentonite is a claystone formed by a complex mineralogical mixture, composed of montmorillonite, illite, and accessory minerals like quartz, cristobalite, feldspars, carbonates, and minor amounts of iron oxy-hydroxides. Bentonite presents complexity at various scales: (1): a single mineral may present different chemical composition within the same quarry (e.g., feldspars solid solutions); (2): montmorillonite presents variability in the cation-exchange distribution while illite may be presented as mixed-layer with smectite sheets; and (3): hardness and crystal size are larger in accessory minerals than in clay minerals, preventing uniform grinding of bentonite. The FEBEX bentonite used is originally from Almería (Spain), and it is a predominantly calcium, magnesium, and sodium bentonite. This Spanish FEBEX bentonite has been hydrothermally altered at laboratory scale for 7–14 years. A thermal gradient was generated by heating a disk of pressed iron powder, simulating the metal waste canister, in contact with the compacted bentonite sample. Hydration was forced from the opposite direction. XRD recorded patterns were very similar. In order to minimize the bias of XRD semi-quantitative determination methods, Rietveld refinement was performed using BGMN software and different structural models. Confidence in the quantification of the main phases allows us to convincingly detect other subtle changes such as the presence of calcite in the hydration front, right at the interface between the saturated and unsaturated bentonite, or the presence of goethite, and not hematite, in the saturated bentonite, near the source of hydration. Smectite component was 72 ± 3% and the refinement was consistent with the presence of ~10% illite, comparable with previous characterizations.

Styles APA, Harvard, Vancouver, ISO, etc.

33

Woo, Duk-Gam, Sang Hyeon Kim et Tae Han Kim. « Solid Fuel Characteristics of Pellets Comprising Spent Coffee Grounds and Wood Powder ». Energies 14, n^o 2 (11 janvier 2021) : 371. http://dx.doi.org/10.3390/en14020371.

Texte intégral

Résumé :

To help mitigate the effects of global warming and fossil fuel depletion caused by human use of fossil fuels, solid fuel pellets were developed from a mixture of spent coffee grounds (SCG) and pine sawdust (PS). The feasibility of SCG-PS pellets as biofuel was also verified by evaluating its fuel quality. An increase in the proportion of SCG in the pellet led to an increase in its calorific value, owing to the high C, H, and oil contents, and increases in the ash and S contents, owing to the high S content in SCG. Analysis of the feedstock particle size distribution revealed that SCG particles are smaller than PS particles; thus, the durability of the pellet decreases as the proportion of SCG increases. Accordingly, the samples with higher SCG proportions (70 and 90 wt.%) did not meet the moisture content standards for biomass solid refuse fuel (bio-SRF) set by the Korea Ministry of Environment, whereas the samples with lower SCG proportions did. In particular, CP10 (10 wt.% SCG + 90 wt.% PS) satisfied the quality standards of Grade 1 wood pellets, demonstrating the feasibility of using SCG as a raw material for biofuel pellet production.

Styles APA, Harvard, Vancouver, ISO, etc.

34

Goncharuk, V. V., A. S. Makarov, L. V. Dubrovina, I. M. Kosygina et I. M. Kruchko. « Dry water fire extinguishing agents with bentonite ». Himia, Fizika ta Tehnologia Poverhni 14, n^o 3 (30 septembre 2023) : 443–49. http://dx.doi.org/10.15407/hftp14.03.443.

Texte intégral

Résumé :

Efficient and environmentally friendly means for fire extinguishing can reduce extreme economic losses from fires and protect people's lives and property. A separate problem is extinguishing oil products on the water surface. Dry water is a new type of environmentally friendly fire extinguishing agent. It is a powder with a water content of more than 90 %, so it has excellent fire extinguishing properties. The purpose of this work was to obtain dry water fire extinguishing powders based on pyrogenic hydrophobic methyl silica with bentonite and to study their fire extinguishing properties in case of extinguishing gasoline on water surface. To obtain dry water fire extinguishing powders, there were used distilled water, Dashukovsky bentonite (Ukraine), and pyrogenic methyl silica (AM-300 brand, Ssp = 300 m2/g, particle size 5–7 nm) (Kalush, Ukraine). Dry water fire extinguishing powder was prepared by mixing the components at a speed of 15000 rpm for 10 s. Were made samples containing 10 wt. % methyl silica, 3, 6, 10, and 15 wt. % bentonite and the corresponding amount of water. The bulk density was 0.423, 0.453, 0.459, and 0.464 g/cm3 for samples of 3, 6, 10, and 15 wt. % bentonite, respectively. Optical microscopy has shown that the particles of the dry water powder have a clearly visible core-shell structure. Dry water fire extinguishing powder is a polydisperse system - most of the particles are single fine particles with a size of 1 micron or less, and there are also agglomerates with a size of more than 5 microns. As a result of the mechanical destruction of individual bentonite particles during high-speed mixing of components, bentonite particles are destroyed, therefore, individual bentonite particles are surrounded by a hydrophobic-hydrophilic mixture of hydrophobic silica nanoparticles and bentonite nanoparticles formed during exfoliation. The study of the fire-extinguishing properties of the dry water powder was carried out by spraying it onto a layer of burning gasoline A92 on water surface. The time to complete extinguishing of the fire and the consumption of the substance per unit area of burning were determined. It has been determined that the time for extinguishing gasoline and the consumption of dry water fire extinguishing powder for extinguishing it depend on the concentration of bentonite and are for 3, 6, 10, and 15 wt. % 9, 7, 6, and 9 s and 0.333, 0.309, 0.284, and 0.260 g/cm3, respectively. The developed dry water fire extinguishing powders are environmentally friendly, have good fire extinguishing properties, and can be used to extinguish oil products on the surface of water bodies.

Styles APA, Harvard, Vancouver, ISO, etc.

35

Zaidan, Shihab A., et Shahad Sarmed Abdull-Razzak. « Effect of bentonite addition on some properties of porcelain ». Journal of Engineering 25, n^o 1 (30 décembre 2018) : 84–99. http://dx.doi.org/10.31026/j.eng.2019.01.07.

Texte intégral

Résumé :

Porcelain is one of the most important ceramic materials with a wide range of traditional and technical applications. Since most mixtures of porcelain have a high sintering temperature, bentonite has been added in this research to improve the characteristics of sintering and burning. The porcelain mixture consisted of the following Iraqi raw materials: 30% wt kaolin, 30 wt% non-plastic clay (grog), 10% wt sodium feldspar, 10 wt% potassium feldspar and 20 wt% flint. After the mechanical mixing process and transfer the powder mixture to the slurry by adding distilled water, then different weight percentage of the sodium bentonite(0, 2.5, 5, 7.5 and 10) wt% was added. The specimens were prepared by using the solid casting method, and after the drying process, the specimens were burned at1100 oC. The results of x-ray diffraction showed that bentonite reduced the crystallization of the main ceramic phases (mullite, quartz), which stimulates the appearance of amorphous glass phases. Also, the loss of mass on ignition increased when the addition of bentonite from 5.66% to 8.2%. There was also a great convergence between the granules of porcelain when adding bentonite and thus increase the shrinkage of the dimensions from 9.33% to 12.37 %. This led to increasing the bulk density from 1.97 g/cm3 to 2.67 g/cm3 at firing temperature 1100oC, and the porosity was decreased from 17.1% to 1.44%. Diametrical strength and flexural strength (bending) increased with bentonite (14.88 to 34.46MPa), (6.2 to 8.65 MPa), respectively.

Styles APA, Harvard, Vancouver, ISO, etc.

36

Mokhtar, Ahmad Kamil Fakhruddin, et Hasmaliza Mohamad. « Effect of Dispersant Amount to Fabrication of 3-D Porous Cordierite through Gelcasting Method ». Materials Science Forum 888 (mars 2017) : 33–36. http://dx.doi.org/10.4028/www.scientific.net/msf.888.33.

Texte intégral

Résumé :

In this research, cordierite was produced using oxide based raw materials (MgO, SiO2 and Al2O3) through glass route method. A mixture of raw material was gone through melting at 1550 °C followed by water quenching. Glass powder produced were then milled for 5 hour to get fine powder. Cordierite powder produced was then used to prepare 3-D porous cordierite ceramic. In this research, gelcasting method was choosen. The dispersant amount added in the cordierite slurry was varied (2.5-5.5g). The cordierite pellet were then characterized using x-ray difraction. Results shows high purity (99%) cordierite was obtained. The porosity and compressive strength were tested. The porosity show when increasing the dispersant amount, the porosity will decrease. For compressive strength increase when the dispersant amount increase.

Styles APA, Harvard, Vancouver, ISO, etc.

37

E, Chuprinov, Lyalyuk V, Zhuravlev F, Kassim D et Lyakhova I. « Study of the influence of different types of bentonite clays on the quality indicators of pellets ». 2,2020 (125) 2,2020, n^o 2,2020 (125) (mars 2020) : 38–43. http://dx.doi.org/10.34185/tpm.2.2020.05.

Texte intégral

Résumé :

Objective: to analyze and determine the influence of bentonite clays of different deposits and exchange ionic complexes on the metallurgical properties of iron ore pellets. Methods: performing rheological studies of bentonite clay samples and their chemical analysis, electron microscopic studies of samples. To assess the metallurgical characteristics of the pellets obtained, the moisture of the pellets, the compressive strength of the wet and dry pellets, the number of dumpings without destroying the wet pellets, and the temperature of the «shock» have been determined. Results: laboratory tests were conducted to determine the suitability of bentonite clays of different mineralogical composition and exchange ion complex for the production of pellets. Tests have shown that the impact resistance and compression resistance of raw pellets at a slightly increased specific consumption of bentonite Cherkasy alkaline-earth bentonite does not concede to the same properties of pellets with the use as a binder alkaline Saryugyhsky bentonite. It is demonstrated that to ensure good quality of raw pellets, an auspicious variety of clays of the Cherkasy deposit are clays of the IV layer, which are a natural mixture of alkaline-earth bentonite of the II layer and palygorskite (III layer). Tests of composite mixtures of clays IV with II and II with III layers showed that the quality of raw pellets with Cherkassky bentonite is slightly worse than with Sarygyuhsky, however, the absolute values of their indicators satisfy the industry requirements. Comparative tests of pelletizing of charges with different humidity and with the addition of 0.5% alkaline bentonite and a mixture of clays of the IV and II layers of the Cherkassky deposit have been carried out. It is shown that with increasing humidity in granules with both types of binders, the dynamic strength, porosity and temperature of the “impact” of granules increase with a minimum difference in the absolute values of indicators with different binders. To objectively confirm the possibility of using alkaline-earth bentonite of the Cherkassky deposit (II-III-IV layers) in the production of pellets, it is necessary to conduct comparative industrial tests at a pelletizing plant (for example, SevGOK), using a concentrate with the in-creased hardness of industrial water. Scientific novelty: the influence of alkaline bentonite replacement in charge for pellet production with alkaline earth, paligorskite clays and mixtures of their forms has been studied. The comparative influence of moisture content of raw pellets on their porosity and strength characteristics with alkaline and alkaline earth bentonites in the charge was studied. Practical significance: using the properties of raw, dry and calcined pellets as an example, the possibility of using less scarce and expensive local bentonite clays instead of expensive exported alkaline clays without impairing the production technology and characteristics of the pellets is shown.

Styles APA, Harvard, Vancouver, ISO, etc.

38

Anzulevich, Anton, Leonid Butko, Dmitrii Kalganov, Dmitrii Pavlov, Valentin Tolkachev, Alexander Fedii, Vasiliy Buchelnikov et Zhiwei Peng. « Optimization of the Microwave-Assisted Carbothermical Reduction Process for Metals from Electric Arc Furnace Dust with Biochar ». Metals 11, n^o 11 (3 novembre 2021) : 1765. http://dx.doi.org/10.3390/met11111765.

Texte intégral

Résumé :

The main purpose of this work was to extract valuable metals from EAF dust with the addition of biochar, using microwaves to control and optimize the carbothermical reduction process. To achieve better microwave penetration and the most homogeneous electromagnetic heat source distribution possible in a sample, the content of EAF dust and biochar in centimeter-size spherical particles prepared by the pelletization process was considered to be radially heterogeneous. The content of EAF dust was determined experimentally and the effective permittivity, permeability, and thermal conductivity of the EAF dust as well as biochar–EAF powder mixture were determined using effective medium approximation. The microwave heating of a multilayered pellet of biochar-containing EAF dust was simulated and investigated. The influence of the distribution of the components within the pellet on the effectiveness of the microwave heating was investigated, as was the influence of the biochar conductivity. The interaction of the pellet with both plane waves in free space and with H10 mode waves in a single-mode waveguide was considered. The most optimal distribution of EAF dust and biochar within the pellet for the reduction process was determined.

Styles APA, Harvard, Vancouver, ISO, etc.

39

Wang, Ying, Huyuan Zhang, Yu Tan et Jianghong Zhu. « Sealing performance of compacted block joints backfilled with bentonite paste or a particle-powder mixture ». Soils and Foundations 61, n^o 2 (avril 2021) : 496–505. http://dx.doi.org/10.1016/j.sandf.2021.01.005.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

40

Sharif, Shafiza Afzan, J. M. Juliewatty et W. A. W. Yusoff. « A Study of Pb (Zr_0.52Ti_0.48)O₃ Ceramic Properties via High Energy Ball Mill ». Advanced Materials Research 1087 (février 2015) : 223–26. http://dx.doi.org/10.4028/www.scientific.net/amr.1087.223.

Texte intégral

Résumé :

Pb (Zr0.52Ti0.48)O3, (PZT) powder has been synthesized using high energy ball milling technique. The synthesized powders were characterized using XRD, SEM, Density, Porosity and Impedance Analyzer. XRD patterns show that the perovskite phase of PZT can be formed from the mixture of starting material after milling for 40 h. The grain sizes of the powder have been estimated to be 1-3 μm. The relationship between the microstructure of the PZT samples and sintering temperature has been discussed. Dense PZT (> 95 % theoretical density) with excellent dielectric properties was obtained when the pellet are sintered at higher temperature with shorter soaking time. The results show that the sample sintered at 1100 °C /1 h yields a clearly uniform grain size with the highest dielectric constant.

Styles APA, Harvard, Vancouver, ISO, etc.

41

Peske, Fabrício Becker, et Ana Dionisia L. C. Novembre. « Pearl millet seed pelleting ». Revista Brasileira de Sementes 33, n^o 2 (2011) : 352–62. http://dx.doi.org/10.1590/s0101-31222011000200018.

Texte intégral

Résumé :

The pearl millet seed is small and its size varies, making sowing more difficult. The pelleting technique increases and homogenizes seed size, but it is essential to determine the physical and physiological characteristics of pelleted seeds. The physiological analysis consisted of: first germination count, final germination, speed emergence index, and seedling emergence. Physical analysis consisted of determining the 1000-seed weight, 1000-seed volume and fragmentation. The control treatment did not receive any coating, and the other 36 treatments combined four binders: bentonite, polyvinyl acetate (PVA), polyvinylpyrrolidone (PVP) and methyl cellulose (Methocel®), and nine powder coating products: microcellulose, plaster, vermiculite, magnesium thermophosphate (Yoorin®), phytic acid, dicalcium phosphate, super simple phosphate (SS), monoamonic phosphate (MAP) and reactive phosphate. Among the materials used to form the pearl millet pellet, the most efficient binders were the polyvinyl acetate and the methyl cellulose, and as coaters, the vermiculite and the microcellulose.

Styles APA, Harvard, Vancouver, ISO, etc.

42

El-Sayed, Saad A., et Mohammed Khairy Elsaid Mohamed. « Mechanical properties and characteristics of wheat straw and pellets ». Energy & ; Environment 29, n^o 7 (2 mai 2018) : 1224–46. http://dx.doi.org/10.1177/0958305x18772414.

Texte intégral

Résumé :

Wheat straw pellets can be easily handled, transported and stored with reduced costs as compared with the raw material. The effect of pelletization process and densification parameters on the properties of the mixture of wheat straw powder and 40% epoxy 1092 as a binder was investigated. The samples were compressed into pellets using the lab-scale hydraulic press under various compacting pressures of 10, 12 and 15 bars and different die shapes and sizes (two cylindrical dies with diameters 10 and 18 mm (S1, S2), respectively, and a new hexagonal die of side length (s) = 6 mm (S3)). It was found that the pelleting process increased the fixed carbon content from 7.14% to 17.36%, the heating value from 15,600 kJ kg−1 to 27,800 kJ kg−1 and the bulk density 10 times when compared to a raw wheat straw powder. It was also found that type S2 at pressure 15 bar is the densest pellet and it had the maximum compression stress that reached 2798.54 kg m−3 and 70.02 MPa, respectively. The cylindrical pellet (type S1) of D = 18 mm at a pressure of 15 bar had the lowest water permeability of 2.35%. Pelletizing process had improved combustion characteristic parameters compared to raw biomass where combustion temperature ranges became higher, maximum weight loss rates and residues became lower that led to a higher combustion efficiency. Thermogravimetric analysis of wheat straw before and after pelleting process was analyzed to evaluate the combustion properties. Scanning electron microscopy images showed that the particle bonding was formed mainly from solid bridges, areas of cohesive failure due to lignin flow, and inter-diffusion between neighboring biomass particles. Images were investigated to explore the importance of compaction process. The images also showed that as the pressure decreases, the gap between the particles increases and produces the less durable pellet. It was found that the slagging index equals 0.38, which indicates that the pellet has a medium slagging inclination and for the fouling inclination (1.79), the wheat straw pellet has a relatively high fouling inclination.

Styles APA, Harvard, Vancouver, ISO, etc.

43

Burnus, R., J. Köhler et A. Simon. « Mn3Nb6O11 und Mg3Nb6O11 - Darstellung von Einkristallen und Strukturverfeinerung / Mn3Nb6O11 and Mg3Nb6O11 - Preparation of Single Crystals and Structure Refinement ». Zeitschrift für Naturforschung B 42, n^o 5 (1 mai 1987) : 536–38. http://dx.doi.org/10.1515/znb-1987-0504.

Texte intégral

Résumé :

Dark green single crystals of Mg3Nb6O11 have been prepared by heating a pellet containing MgO, Nb, Nb2O5 (15:14:8) at 1550 °C in a Nb-container. Single crystals of the isotypic Mn3Nb6O11 were formed by heating a mixture of LiF, MnF2, Mn, NbO, NbO2 (1:1:1:1:2) in a corundum crucible at 750 °C. Both compounds crystallize in the trigonal space group P3̄ m 1 (Z = 1) with a = 6.041(1), c = 7.466(1) and a = 6.080(1), c = 7.627(1), respectively. The positional parameters for Mg3Nb6O11 are in excellent agreement with those determined by Marinder from powder data.

Styles APA, Harvard, Vancouver, ISO, etc.

44

Zhang, X., Y. Pan et T. T. Meek. « Characterization of microwave-sintered ceramic composites ». Proceedings, annual meeting, Electron Microscopy Society of America 51 (1 août 1993) : 1136–37. http://dx.doi.org/10.1017/s0424820100151519.

Texte intégral

Résumé :

Industrial microwave heating technology has emerged as a new ceramic processing technique. The unique advantages of fast sintering, high density, and improved materials properties makes it superior in certain respects to other processing methods. This work presents the structure characterization of a microwave sintered ceramic matrix composite.Commercial α-alumina powder A-16 (Alcoa) is chosen as the matrix material, β-silicon carbide whiskers (Third Millennium Technologies, Inc.) are used as the reinforcing element. The green samples consisted of 90 vol% Al2O3 powder and 10 vol% ultrasonically-dispersed SiC whiskers. The powder mixture is blended together, and then uniaxially pressed into a cylindrical pellet under a pressure of 230 MPa, which yields a 52% green density. The sintering experiments are carried out using an industry microwave system (Gober, Model S6F) which generates microwave radiation at 2.45 GHz with a maximum output power of 6 kW. The composites are sintered at two different temperatures (1550°C and 1650°C) with various isothermal processing time intervals ranging from 10 to 20 min.

Styles APA, Harvard, Vancouver, ISO, etc.

45

Foudzi, Farhana Mohd, Norhamidi Muhamad, Abu Bakar Sulong et Hafizawati Zakaria. « Flow Behavior Characteristic for Injection Process Using Nano-Yttria Stabilized Zirconia for Micro Metal Injection Molding (µMIM) ». Applied Mechanics and Materials 44-47 (décembre 2010) : 480–84. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.480.

Texte intégral

Résumé :

Micro metal injection molding (µMIM) prior to conventional plastic injection molding (PIM) has become widely demanding due to its smaller size, more complex geometric surface and time consuming on its product. Metal and ceramic in powder form of various sizes up to µm is mixed with binder system to produce products that meet the requirements. Nano size yttria stabilized zirconia (YSZ) with average particle size of 25nm, was tested both physically and mechanically for its properties before mixing and injection process using several testing such as Scanning Electron Microscopy (SEM), Energy Dispersive X-ray (EDX), pycnometer density, critical powder volume percentage (CPVP) and rheology respectively. Grain shape for YSZ particle is near spherical with the diameter range between 21.2 – 33.5nm while the CPVP shows the highest powder loading was 41.4%. Binder system of 70% palm stearin and 30% polypropylene (PP) was then mixed with YSZ at 37%, 38% and 39% by using internal mixer with roller blade type. By using CPVP of 41.4% as the guideline, mixing was done beyond the critical point until it is capable of becoming the dough mixture and was found that 43% powder loading is the highest loading it can achieved. This dough form of every mixture of powder loading was crushed to obtain pellet size as the feedstock. Rheology test was carried out for each powder loading at 180oC, 190oC and 200oC with the load increasing from 10N to 20N to determine the plastic behavior and best relationship between viscosity (Pa.s) and shear rate (1/s). Dilatant flow behavior for all the powder loadings and smooth data distribution during testing at 180oC was observed respectively. Critical parameters involving in injection process such as mold temperature (oC), melt temperature (oC), pressure (bar) and time (s) was manipulated for every powder loading to obtain the best result with no defects such as shot and flashing. Each critical parameter increased gradually as the powder loading (%) increased. Debinding and sintering process will be carried out to determine the strength and toughness by using micro hardness and micro tensile test respectively.

Styles APA, Harvard, Vancouver, ISO, etc.

46

Aurisicchio, C., G. L. Calestani, C. De Blasi, D. Fiorani, D. Manno et M. Palmisano. « Structural and superconducting study of the system (Pb,Bi)-Sr-Ca-Cu-O ». Proceedings, annual meeting, Electron Microscopy Society of America 48, n^o 4 (août 1990) : 98–99. http://dx.doi.org/10.1017/s0424820100173625.

Texte intégral

Résumé :

The results of a study of the structural and superconducting properties performed on a (Pb, Bi) - Sr - Ca - Cu - O systei by x rays, transmitted electron aicroscopy (CBED) and magnetic susceptibility measurements are reported.The sample was prepared by solid state reaction of a mixture of Bi2O3, PbO, SrCO3, CaCO3 and CuO, according to the starting composition Bi2PbO.4Sr2Ca3Cu4Ox. A slight excess of Ca and Cu, with respect to the stoichiometric formula (Bi, Pb)2Sr2Ca2Cu3Ox was utilized in agreement with in order to minimize the reaction time required for the obtainment of the c= 3.7 nm phase and to avoid the presence of the c-shorter phase (−3.1 nm) in the final product. The mixture was ground, heated at 780 oC for 8h and then cooled to room temperature in air and annealed again at 840 oC for 60h. Finally a textured sample was obtained by pressing the powder into a pellet which was annealed at 840 oC for 8h.

Styles APA, Harvard, Vancouver, ISO, etc.

47

Van Geet, M., G. Volckaert et S. Roels. « The use of microfocus X-ray computed tomography in characterising the hydration of a clay pellet/powder mixture ». Applied Clay Science 29, n^o 2 (avril 2005) : 73–87. http://dx.doi.org/10.1016/j.clay.2004.12.007.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

48

Duranay, Neslihan. « CO2 emission from combustion of lignite, waste plastics and biomass mixture pellets ». Chemical Industry and Chemical Engineering Quarterly 25, n^o 3 (2019) : 239–46. http://dx.doi.org/10.2298/ciceq180921002d.

Texte intégral

Résumé :

Combustion is a familiar technique for disposal of urban wastes such as plastics when their recycling is impractical. It offers energy recycling and waste diminution. In this paper, combustion behaviours of blend pellets composed of binary and triple mixtures of plastic wastes, biomass and lignite in a laboratoryscale fixed-bed combustion system were examined. The materials chosen as waste plastic, biomass and lignite were, respectively, market plastic bags, furniture plant waste powder and Bing?l Karl?ova lignite. The effect of varied blend pellet composition on the combustion behaviour and CO2 emission in flue gas during combustion was examined. It was observed that the rate and efficiency of combustion increased with increasing plastic ratio in the blend pellets. It was found that the amount of carbon increased with the ratio of waste plastics added to blends, which also increased the CO2 ratio in the flue gas during the volatile matter combustion period. It was concluded that burning waste plastic bags with low-quality lignite or waste biomass could be a viable option to get rid of them and to gain energy.

Styles APA, Harvard, Vancouver, ISO, etc.

49

Iyer, Jayant, Isha Saraf, Andrew Ray, Michael Brunsteiner et Amrit Paudel. « Assessment of Diverse Solid−State Accelerated Autoxidation Methods for Droperidol ». Pharmaceutics 14, n^o 6 (24 mai 2022) : 1114. http://dx.doi.org/10.3390/pharmaceutics14061114.

Texte intégral

Résumé :

The present study aimed to investigate methods for accelerating autoxidation of crystalline drugs in the solid-state that can potentially predict real−time stability. Solid droperidol (DPD) was selected as the model drug. A common free−radical initiator, 2,2′−azobisisobutyronitrile (AIBN), was used to induce autoxidation in solutions. AIBN decomposes at elevated temperatures to yield carbon−centred cyano−isopropyl free radicals that can auto−oxidize neighboring drug molecules. Although the reaction of AIBN is relatively straightforward in solution, it is less so in solids. In this study, we used solid AIBN mixed with DPD powder in the presence and absence of pressurized oxygen headspace. Samples were prepared directly in the form of binary mixtures with DPD and additionally in the form of powder compact/pellet with DPD. The main challenge in carrying out the reaction was related to the preservation of AIBN at elevated temperatures due to the disintegration of the pellet containing the latter. A commercially available free−radical coated silica particle (i.e., 2,2,6,6−tetramethyl−1−piperinyloxy (TEMPO) or (SiliaCATTM TEMPO)) was tested as a potential stressor, but with limited success to induce autoxidation. The most valuable results were obtained when a physical mixture of pre−milled PVP K−60 containing free radicals and DPD was exposed to elevated oxygen−temperature conditions, which yielded significant degradation of DPD. The study highlights the practical challenges for conducting accelerated solid−state stress studies to assess the autoxidation susceptibility of drugs using traditional free−radical initiators and presents a proof of application of milled PVP with free−radical as a potential alternative.

Styles APA, Harvard, Vancouver, ISO, etc.

50

Seo, Joo-Young, Dong-Gyu Kim, Kyoung-Duck Kim, Yong-Jin Kang et Sang-Min Lee. « Effects of Supplemental Medicinal Hem Mixture, Laver Powder and Paprika Powder in Extruded Pellet on Growth and Feed Utilization of Juvenile Olive Flounder, Paralichthys olivaceus ». Korean Journal of Fisheries and Aquatic Sciences 42, n^o 4 (31 août 2009) : 395–98. http://dx.doi.org/10.5657/kfas.2009.42.4.395.

Texte intégral

Styles APA, Harvard, Vancouver, ISO, etc.

Articles de revues sur le sujet « Bentonite pellet/powder mixture »

Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres