Capacity Of Different Materials Research Articles

A Study on the Ability of Nanomaterials to Adsorb NO and SO2 from Combustion Gases and the Effectiveness of Their Separation.

Climate neutrality for the year 2050 is the goal assumed at the level of the EU27+UK. As Romania is no exception, it has assumed the gradual mitigation of pollution generated by the energy sector, and by 2030, according to 'Fit for 55', the share of energy from renewable sources must reach 42.5% from total energy consumption. For the rest of the energy produced from traditional sources, natural gas and/or coal, modern technologies will be used to retain the gaseous noxes. Even if they are not greenhouse gases, NO and SO2, generated from fossil fuel combustion, cause negative effects on the environment and biodiversity. The adsorption capacity of different materials, three nanomaterials developed in-house and three commercial adsorbents, both for NO and SO2, was tackled through gas chromatography, elemental analysis, and Fourier-transform infrared spectroscopy. Fe-BTC has proven to be an excellent material for separation efficiency and adsorption capacity under studied conditions, and is shown to be versatile both in the case of NO (80.00 cm3/g) and SO2 (63.07 cm3/g). All the developed nanomaterials generated superior results in comparison to the commercial adsorbents. The increase in pressure enhanced the performance of the absorption process, while temperature showed an opposite influence, by blocking the active centers on the surface.

Development of High Temperature Water Sorbents Based on Zeolites, Dolomite, Lanthanum Oxide and Coke

Methanation is gaining attention as it produces green methane from CO2 and H2, through Power-to-Gas technology. This process could be improved by in situ water sorption. The main difficulty for this process intensification is to find effective water sorbents at useful reaction temperatures (275-400 °C). The present work comprises the study of the water sorption capacity of different materials at 25-400 °C. The sorption capacity of the most studied solid sorbents (zeolites 3A & 4A) was compared to other materials such as dolomite, La2O3 and cokes. In trying to improve their stability and sorption capacity at high temperatures, all these materials were modified with alkaline-earth metals (Ba, Ca & Mg). Lanthana-Ba and dolomite sorbents were the most promising materials, reaching water sorption values of 120 and 102 mgH2O/gsorbent, respectively, even at 300 °C, i.e., values 10-times higher than the achieved ones with zeolites 3A or 4A under the same operating conditions. At these high temperatures, around 300 °C, the water sorption process was concluded to be closer to chemisorption than to physisorption.

Ethyl mercaptan removal from gas streams using regenerable Co/Fe modified hexaniobate nanotubes

In this study, Fe and Co/Fe modified H4Nb6O17 nanotubes as high efficiency materials for C2H5SH removal were synthesized by ion exchange-flocculation-calcination process. The results showed that Co/Fe modified H4Nb6O17 nanotubes can enhance removal effect of C2H5SH. C2H5SH breakthrough adsorption capacity of different materials decline as follows: Co/Fe-HNT-0.3 (36.20 mg·g−1) > Co/Fe-HNT-0.5 (33.70 mg·g−1) = Co/Fe-HNT-0.1 (33.70 mg·g−1) > 10 %Fe-HNT (29.96 mg·g−1) > HNT-450 (11.23 mg·g−1) > HNT (6.24 mg·g−1). After four cycle regenerations, the Co/Fe-HNT-0.3 can still maintain C2H5SH removal efficiency of 96.5 %. The characterization results indicated that the loaded metal of Fe and Co/Fe can improve the structure, morphology, thermal stability, and rich pore structure of the H4Nb6O17 nanotubes. It also indicated that Co/Fe oxides were the mainly active substances on H4Nb6O17 nanotubes. These characteristics enhance the adsorption and activation of C2H5SH by Fe and Co/Fe loaded H4Nb6O17 nanotubes. The introduction of Co additives promotes the reduction of Fe3+ and the formed Fe3O4 serve as the main active species to promote the oxidation of adsorbed C2H5SH. This study presents an efficient material of Co/Fe modified H4Nb6O17 nanotubes for the removal of C2H5SH.

Damping capacity of materials and its effect on the dynamic behavior of structures. Review

Damping is very important when studying the vibrations of bridge structures. A distinction is made between structural damping and damping due to internal friction in the material. The damping ability of the material allows it to absorb energy for irreversible processes during its cyclic deformation. That is why, when designing bridge structures, special attention is paid to the damping properties of the material from which they are made. At the same time, the experimental determination of the damping ability of a material is a more difficult task than the determination of any other mechanical characteristic. In recent years, modern composite materials have been increasingly used in civil and transport construction. The main feature of composite materials in terms of damping ability is the combination in a single conglomerate, which is characterized by emergence, of the components (phases of the composite), which have different elastic and damping properties. However, the damping of a structure has a significant effect on its dynamic behavior, for example, the phenomenon of aerodynamic instability of galloping is associated with negative aerodynamic damping. One of the aim of the paper is to analyze the effect of composite materials damping on bridge aerodynamic stability. A series of experiments was carried out to assess the dynamic behavior of a bridge in a wind flow at various levels of damping. At the first part we discussed the damping capacity of different materials, it was shown that composite materials have better dissipative properties in comparison with metals and their alloys composite materials. At the second part we have considered the different ways for determination of the damping capacity of the material. Further we provided a series of experiments to analyze the effect of composite materials damping on bridge aerodynamic stability.

Photoacoustic Spectroscopy for Curing Time Determination of an Acrylic Nanocomposite

Photoacoustic spectroscopy (PAS) has been widely used as a nondestructive and sensitive analytical technique used to determine the thermal diffusivity, effusivity and heat capacity of different materials. In this work, the open cell photoacoustic technique (OPC) technique was used for the kinematic study of heat transfer processes as a function of time for curing nanoresin composites. An exponential growth of the signal during the process of curing was observed. The nanoresin was based on silver nanoparticles (AgNPs) that were synthesized using a green method from an aqueous extract of Capsicum annuum var annuum as an Ag reducer and an acrylic resin. It was cured using a violet laser beam with a wavelength of 405 nm with an average power of 120 mW. The characteristic curing time was measured as a function AgNPs concentration of 0.0, 5.16, 7.27, 11.85, 14.50, 16.86 and 20.96 × 10−4 vol%. The results showed an increase in the curing time of composite resin containing the AgNPs compared to the pure resin. This study has applications in printing parts using laser stereolithography.

Influence of testing parameters on the load-bearing capacity of prosthetic materials used for fixed dental prosthesis: A systematic review and meta-analysis

The aim of this study was to systematically review the literature to assess static fracture strength tests applied for FDPs and analyze the impact of periodontal ligament (PDL) simulation on the fracture strength. Original scientific papers published in MEDLINE (PubMed) database between 01/01/1981 and 01/06/2010 were included in this systematic review. Data were analyzed considering the test method (static loading), material type (metal-ceramic-MC, oxide all-ceramic-AC, fiber reinforced composite resin-FRC, composite resin-C), PDL (without or with) and restoration type (single crowns, 3-unit, 4-unit, inlay-retained and cantilever FDPs). The selection process resulted in the 72 studies. In total, 377 subgroups revealed results from static load-bearing capacity of different materials. Fourteen metal-ceramic, 190 AC, 121 FRC, 45 C resin groups were identified as subgroups. Slightly decreased results were observed with the presence of PDL for single crowns (without PDL=1117±215 N; with PDL=876±69 N), 3-unit FDPs (without PDL=791±116 N; with PDL=675±91 N) made of AC, 3-unit FDP (without PDL=1244±270 N; with PDL=930±76 N) and inlay-retained FDP (without PDL=848±104 N; with PDL=820±91 N) made of FRC and 4-unit FDPs (without PDL=548±26 N; with PDL=393±67 N) made of C. Overall, for single crowns, fracture strength of FRC was higher than that of AC and MC; for 3-unit FDPs FRC=C>AC=MC; for 4-unit FDPs AC>FRC>C and for inlay-retained FDPs, FRC=AC. An inclination for decreased static fracture strength could be observed with the simulation of PDL but due to insufficient data this could not be generalized for all materials used for FDPs.

Contact angle hysteresis effect on the thermocapillary migration of liquid droplets

Thermocapillary migration describes a phenomenon where a liquid droplet spreads from warm to cold regions due to the interfacial tension gradients. Since the contact angle hysteresis effect is involved during the migration process, we consider the hysteresis effect and rectify the theoretical model to predict the migration velocity on solid surfaces. By conducting migration experiments on surfaces with different magnitudes of the hysteresis effect, we verify the validity of the theoretical derivation. This study advances the understanding of the interfacial phenomenon of thermocapillary migration, moreover, offers an insight into the migration capacity of different materials and guides the design of key components associated with the thermal gradients.

Polysaccharide nanoparticles for protein and Peptide delivery: exploring less-known materials.

Finding adequate carriers for protein and peptide delivery has become an urgent need, owing to the growing number of macromolecules identified as having therapeutic potential. Nanoparticles have emerged in the field as very promising vehicles and much work has been directed to testing the capacity of different materials to compose the matrix of these carriers. Natural materials and, specifically, polysaccharides have been taking the forefront of the challenge, because of several favoring properties that include the higher propensity to exhibit biodegradability and biocompatibility, and also the high structural flexibility. The majority of works found in the literature regarding polysaccharide nanoparticles uses very popular materials like chitosan or hyaluronic acid. This review is aimed at describing and exploring the potential of polysaccharides that are not so well known or that are less explored. For those, the main properties will be described, together with an overview of the reported applications as nanoparticle matrix materials.

Storage of N2, He and CH4 in coal: Study and application in a practical case in the central Asturian coal basin (northern Spain)

The behaviour of different gases (He, N 2 and CH 4 ) in coal was analyzed using a device for treating raw coal, designed for taking samples in the mine. This device was subsequently used to transport the samples and inject them with the gases under study. Experiments were conducted under different pressures, and a clear relationship was found between the drop in pressure and the occupation of different storage levels. On analysing the pressure evolution it was found that helium rapidly stabilised due to the characteristics of this gas. As for the other gases, N 2 showed a percentage fall much lower than that of CH 4 . In order to compare the storage capacity of different materials with respect to these gases, experiments were performed with different materials which form the mine's ceiling and walls. It was shown that the fall in pressure is very inferior. A fitting equation relating the evolution of pressure with time is proposed which may be used to define the time needed for the gas to stabilize in the coal. A normalized equation, very similar to that proposed by Langmuir, is likewise obtained to characterize the adsorption and desorption processes.

Adsorption of pesticides Carbetamide and Metamitron on organohydrotalcite

Abstract This paper reports on the adsorption of low polarity pesticides Carbetamide and Metamitron on hydrotalcite [Mg 3 Al(OH) 8 ] 2 CO 3 · n H 2 O and organohydrotalcites [Mg 3 Al(OH) 8 ] 2 DDS· n H 2 O with different degree of dodecyl sulphate (DDS) saturation. The adsorbents and the adsorption products were characterized by X-ray diffraction method and FT-IR spectroscopy. Both pesticides were better adsorbed on organohydrotalcite with higher DDS saturation, while their adsorption on inorganic hydrotalcite was very low. The results indicate that the adsorption capacity of different materials depends on their nature as well as structure and polarity of the pesticides and suggest the possibility of use of organohydrotalcite to uptake the Carbetamide and Metamitron from contaminated waters. The results also showed that the recyclability of organohydrotalcite and their reutilization as adsorbent is possible.

Selection of low swelling materials for protein adsorption from white wines

Summary The protein adsorption capacity of different materials was evaluated to assess their potential efficacy as alternative adsorbents for the removal of proteins from wines, with the purpose of finding suitable low‐swelling materials that could be used in a percolated bed. The adsorbents tested were thermally treated sodium bentonite, low‐swelling adsorbing clays, ion exchange resins and other protein adsorbents (silica gel, hydroxyapatite and alumina). The materials were evaluated by analysing both the capacity to stabilize untreated white wines, according to a heat test, and by characterizing the adsorption isotherms of bovine serum albumin (BSA) in a model wine (water, ethanol and K‐bitartrate). Breakthrough curves in a packed bed were determined experimentally for some materials, showing the influence of the adsorption isotherm shape. Some ion‐exchange resins showed a favourable behaviour and have good potential as alternative adsorbents.

Recent developments and applications of the hot disk thermal constants analyser for measuring thermal transport properties of solids

When thermal conductivity and diffusivity are measured with the hot disk thermal constants analyser, hot disk sensors or G-probes of different designs are used. The design of these sensors can be described as a double spiral etched out of a 10 μm thick metal foil sandwiched between two thin insulating sheets of an electrically insulating material. So far mostly nickel and in a few instances platinum foil have been used as the sensing' material, For experiments from 30 K up to about 450 K the polyimide Kapton with a thickness of 25 μm has been used as insulating material while for temperatures beyond 450 K and up to about 1200 K a 100 μm thick mica material is used. Attempts are presently being made also to use other insulating materials, which might further increase the temperature range of the sensors. Beside work on the further development of the sensors, work is going on to extend the application of this experimental technique to cover new experimental situations, Presently, some options in addition to the standard system can be utilised. These options include possibilities to measure the thermal transport properties of anisotropic bulk materials, thin insulting sheets of low conducting materials, and slabs of material with medium to high thermal conductivity. in addition there is a facility to measure the specific heat capacity of different materials directly. When the standard experimental technique is applied, the usual experimental arrangement is to place one piece of the sample material on either side of the sensor. However, attempts have recently been made to cover one side of the sensor with a material with known thermal properties and then place the material with unknown properties in contact with the other side of the probe.

Absorptive Capacity of Different Materials Ordinarily Used for Bedding

Summary Ten pounds of oat, wheat and rye straws cut and whole were soaked from one to two hours in sufficient urine to completely submerge the sacks containing the straws. The same procedure was followed in which well-water was used instead of urine. The materials were allowed to soak for one to two hours and then suspended and allowed to drain until dripping had ceased, after which the content of the sack was emptied into a tub and weighed. The increase in weight of the bedding materials was assumed to be due to the amounts of urine or water retained by the various materials. No appreciable difference in absorptive capacity was noted between cut and whole straws, and straws from different cereals. Such minor differences as are indicated might be due to the completeness of soaking, or draining. The temperature and humidity of the room in which the materials were soaked and allowed to drain were not maintained at the same point, which might result in a difference in weight. That the original moisture content of the materials used for bedding affect the absorptive capacity of the materials is indicated by the sawdust used in the Maryland experiments. The data from the South Dakota Station indicate that the whole cereal straws provide satisfactory litter. Because of the abundance and cheapness of these straws, they can be recommended in preference to any other materials for this area. The manurial value of the cereal straws is also greater than the manurial value of sawdust or shavings, materials ordinarily substituted for cereal straws. The data did not indicate greater absorptive powers for cut straws; therefore, it would not seem advisable to cut cereal straws for bedding except where storage room for straw is at a premium.