Monolithic Form Research Articles

Full-mouth reconstruction with Implant and Tooth-supported Zirconia Restorations in a Digital Workflow

Zirconia has become a popular restorative material regarding the mechanical and biocompatibility advantages. Monolithic and translucent forms of zirconia advanced the aesthetics of this material, making it the material of choice for both tooth- and implant- supported restorations. Also, digital fabrication of zirconia not only enables accurate restorations but also provides time efficiency. The present case report demonstrates the rehabilitation of a patient who has generalized tooth wear with implant- and tooth supported monolithic zirconia restorations with buccal veneers in a newly established occlusal vertical dimension. The treatment process was completed in a digital workflow as the impressions were taken with a powder-free intraoral scanner and the digital data were send to the dental laboratory to fabricate the restorations. Monolithic zirconia restorations with buccal feldspathic veneers were completed without any adjustments in only two appointments. The patient was satisfied and the restorations have been in service for two years.

Recent Advanced of Multiple Unite Pellet System (MUPS) Technology in Formulation of Pharmaceutical Products: A Review

The oral route of drug administration is the most important and most user-friendly route of administration. In recent years, Multiple Unit Pellet Systems (MUPS) tablets are widely used in solid dosage form design. MUPS is considered to provide pharmacokinetic advantages compared to monolithic dosage forms. Combination of drug substances and release profiles can be provided by formulating the MUPS tablets with different pellet qualities or combining pellets with drugs in powder or granulated form. MUPS tablet contains several hundred of coated pellets of active pharmaceutical ingredients which delivered the drug at predetermined rate and absorption to provide constant blood profile. MUPS are easily administered as disintegratable tablet which disperse into their subunits across the stomach and the small intestine, leading to predictable oral transition and constant bioavailability.

Monolithic Nanoporous Gold Foams with Catalytic Activity for Chemical Vapor Deposition Growth of Carbon Nanostructures

While bulk gold is generally considered to be a catalytically inactive material, nanostructured forms of gold can in fact be highly catalytically active. However, few methods exist for preparing high-purity macroscopic forms of catalytically active gold. In this work, we describe the synthesis of catalytically active macroscopic nanoporous gold foams via combustion synthesis of gold bis(tetrazolato)amine complexes. The resulting metallically pure porous gold nanoarchitectures exhibit bulk densities of <0.1 g/cm3 and Brunauer-Emmett-Teller (BET) surface areas as high as 10.9 m2/g, making them among the lowest-density and highest-surface-area monolithic forms of gold produced to date. Thanks to the presence of a highly nanostructured gold surface, such gold nanofoams have also been found to be highly catalytically active toward thermal chemical vapor deposition (CVD) growth of carbon nanotubes, providing a novel method for direct synthesis of carbon nanostructures on macroscopic gold substrates. In contrast, analogous copper nanofoams were found to be catalytically inactive toward the growth of graphitic nanostructures under the same synthesis conditions, highlighting the unusually high catalytic propensity of this form factor of gold. The combustion synthesis process described herein represents a never-wet approach for directly synthesizing macroscopic catalytically active gold. Unlike sol-gel and dealloying approaches, combustion synthesis eliminates the time-consuming diffusion-mediated steps associated with previous methods and offers multiple degrees of freedom for tuning morphology, electrical conductivity, and mechanical properties.

Investigation of alumina aerogel structural characteristics at different «precursor-water-ethanol» ratio

Alumina aerogels in the form of monoliths were obtained within a work. Gels were synthesized using a sol-gel process. An inorganic salt, aluminum chloride hexahydrate, was used as a precursor. Hydrolysis and condensation reactions were carried out in a medium of water and ethanol, and epichlorohydrin was the initiator of the gelation process. In order to identify an appropriate compositions of components gels preparation the phase equilibrium of the «epichlorohydrin-ethanol-water» system was experimentally studied. The effect of the precursor-water-ethanol ratio on the aerogels’ final characteristics was investigated. To determine the characteristics of alumina aerogels method of nitrogen adsorption, helium pycnometry, transmission and scanning transmission electron microscopy with x-ray microanalysis were used. The resulting materials have high specific surface area from 464 to 859 m2/g and low density from 65.6 to 121.1 kg/m3. The structure of alumina aerogels consists of flake-like particles which form the interconnected network. Such materials are promising for use as heat-insulating materials and catalysts.

Activated Carbon Monolith Derived from Coconut Husk Fiber as Electrode Material for Supercapacitor Energy Storage

Biomass-derived porous activated carbon materials have been receiving considerable attention in energy-storage devices especially for supercapacitor due to abundant, renewable, sustainable, and cost-effective production. In this study, porous activated carbon material with monolithic form has been successfully prepared from coconut husk fiber through one-stage integrated pyrolysis and ZnCl2 impregnation. Different physical activation temperature is the main focus in this study including 750, 800, 850, and 900 °C. The reduction of monolith dimensions such as mass, diameter, thickness and density have been reviewed as physical properties. Furthermore, the supercapacitor cells were performed with cyclic voltammetry t 1 M H2SO4 aqueous electrolyte at low scan rate of 1 mV s−1. The supercapacitor device based on the CFM-800 samples exhibited highest specific capacitance of 216 F g−1. This sample also performed a promising performance with an energy density of 30.00 Whkg−1 and a high power density of 108.57 Wkg−1. These results demonstrate that the coconut husk fiberhas been a high potential to as raw material for porous activated carbon monolith through low cost, vehicle and short-time processing with high-performance supercapacitors energy storage.

A High Potential of Biomass Leaves Waste for Porous Activated Carbon Nanofiber/Nanosheet as Electrode Material of Supercapacitor

Since porous carbon materials derived from biomass, with low cost, abundant and sustainable, relatively easy fabrication, high electrical conductivity, large specific surface area (SSA), surface morphology with nanomaterial structures, and superior electrochemical stability have attracted attention which are strong and highly trusted to be a candidate for the electrode material of supercapacitor energy storage. This study highlighted recent laboratory-scale methods for preparing activated carbon nanostructures from leaves biomass wastes. Four types of focused leaves waste including acacia leaves, pineapple leaves, and Terminalia catappa leaves (TCL), and Pandanus tectorius leaves (PTL). Leave wastes were converted into activated carbon by KOH activation and one-stage integrated pyrolysis both of carbonization and physical activation. Symmetric supercapacitor electrode ware performed with sandwich-type in monolith form without adhesive materials. Among the raw materials found in this study, nanofiber structures dominated the surface morphology of carbon monolith, especially in acacia leaves, pineapple leaves, and TCL. Interestingly, the same basic material of TCL could perform two different nanostructures including nanofiber and nanosheet. In addition, the percentages of carbon and oxygen contents in the sample were also provided. Furthermore, supercapacitor cells exhibited the highest specific capacitance are activated carbon derived from pineapple leaves as high as 150 F g−1 in 1M H2SO4 aqueous electrolyte at a low scanning rate of 1 mV s−1. Finally, these results confirmed that leaves biomass wastes have high potential as a raw material of activated carbon nanofiber/nanosheet structure to be applied in supercapacitor electrodes.

State Regulations and Elitisation: A Study of Civil Society Elites in Indonesia and Cambodia

This article analyses how and to what extent state regulation of civil society organisations (CSOs) have resulted in elitisation, i.e., the process of obtaining elite status within and beyond civil society. This is studied in the context of emerging democracy in Indonesia and shrinking civic space in Cambodia. Combining Bourdieu’s concepts of field and elite with strategic action fields, the article uses data from interviews with civil society leaders. It finds different patterns. In Indonesia, elitisation occurs through a process of CSO formalisation and bureaucratisation, with elites gaining legitimacy owing to their formal offices. As a result, competition for formal positions intensifies: This is particularly notable among national CSO leaders, who may shift their activities to the grassroots level to seek further empowerment and other capitals to legitimise their elite status, facilitate the rise of leaders in existing fields, and create pluralistic forms of elites. Regulations have also resulted in the marginalisation of non-formal elites and shifted the locus of legitimacy from activism to formalism. Meanwhile, in Cambodia, regulatory formalisation and bureaucratisation has not only reduced the space for elite competition and level of competitiveness, but also created ‘most dominant actors’ or ‘hyper-elites’ who are loyal to and support the regime and its priorities while punishing those who do not. This has resulted in a monolithic form of elites.

Deep eutectic solvent-assisted phase separation in chitosan solutions for the production of 3D monoliths and films with tailored porosities

A facile and greener methodology to obtain pure chitosan-based 3D porous structures in the form of monoliths and films is proposed. It is based on a modified evaporation-induced phase separation process in a chitosan solution precursor. In this approach, a deep eutectic solvent (DES) is used as the nonsolvent system and an ecofriendly, cost effective, simple and versatile alternative for the production of highly structured chitosan materials. The porous heterogeneous structure can be fine-tuned by varying the chitosan content in the precursor solution and chitosan/DES ratio, and enabled the structured polymer to absorb large amounts of water to form hydrogels. This is a versatile and unexplored approach to design porous chitosan with tailored morphology in the absence of crosslinkers, which, based on preliminary studies on V. cholerae biofilm formation, is expected to open new avenues for various applications in biomedical, catalysis, water purification, filtration and other areas where the control of bacterial biofilm formation is critical.

Fabrication of Green Diatomite/Chitosan-Based Hybrid Foams with Dye Sorption Capacity.

The latest tendency of the scientific community regards the development of different classes of green materials able to solve pollution problems caused by industrial and human activity. In this paper, chitosan and diatomite were used to produce a broad-spectrum hybrid adsorbent, either in powder or in monolithic form for environmental pollutant removal. Diatomite–chitosan-based powders and porous diatomite–chitosan hybrids were prepared and characterized by chemical-physical, thermal and morphological analysis. Moreover, their adsorbent capacity towards anionic dye (Indigo Carmine) was also evaluated. Obtained data showed that chitosan improves the adsorption capacity of both systems, increasing the uptake of dye in both diatomite–chitosan systems.

Three-dimensional pore structure of activated carbon monolithic derived from hierarchically bamboo stem for supercapacitor application

A three-dimensional pore structure on activated carbon derived from hierarchically bamboo stem was synthesized in the monolithic form for increased applicability as a supercapacitor electrode. The preparation involved two step carbonizations, using a chemical activation at different concentrations. Subsequently, the morphology, chemical content, specific surface area and pore size distribution, as well as crystalline degree were evaluated with scanning electron microscopy, energy X-ray (EDX), N2 sorption and X-ray diffraction, respectively. Therefore, cyclic voltammetry (CV) was used to assess the electrochemical performance, in a two electrode system. The result shows the significant impact of the three-dimensional structure on electrochemical performance, and the optimized sample exhibited specific capacitance of 168.8 F g-1, energy density of 23.44 Wh kg-1, and power density of 84.46 W kg-1.

Carbon Xerogels for Effluent Treatment

The adsorption process of carbonized xerogels in the form of porous microspheres or monoliths was found to be reversible. This indicated that the xerogels could be reusable, making the process of e...

Continuous Hydrogenation of Aqueous Furfural Using a Metal-Supported Activated Carbon Monolith.

Continuous hydrogenation of aqueous furfural (4.5%) was studied using a monolith form (ACM) of an activated carbon Pd catalyst (∼1.2% Pd). A sequential reaction pathway was observed, with ACM achieving high selectivity and space time yields (STYs) for furfuryl alcohol (∼25%, 60–70 g/L-cat/h, 7–15 1/h liquid hourly space velocity, LHSV), 2-methylfuran (∼25%, 45–50 g/L-cat/h, 7–15 1/h LHSV), and tetrahydrofurfuryl alcohol (∼20–60%, 10–50 g/L-cat/h, <7 1/h LHSV). ACM showed a low loss of activity and metal leaching over the course of the reactions and was not limited by H2 external mass transfer resistance. Acetic acid (1%) did not significantly affect furfural conversion and product yields using ACM, suggesting Pd/ACM’s potential for conversion of crude furfural. Limited metal leaching combined with high metal dispersion and H2 mass transfer rates in the composite carbon catalyst (ACM) provides possible advantages over granular and powdered forms in continuous processing.

Graphene-Metal-Metastructure Monolith via Laser Shock-Induced Thermochemical Stitching of MOF Crystals

Summary The hybrids of porous graphene and metal nanoparticles (MNPs) in a monolithic form are widely explored in energy and environmental sciences in which uniform dispersion of stable MNPs across the graphene backbone are required. However, it remains challenging to fabricate such a composite in a scalable and straightforward manner. Here, we demonstrate the direct laser conversion of metal-organic framework (MOF) crystals to a monolithic porous graphene with exceptional dispersion of MNPs in air. The strong interaction between laser pulses and MOF crystals created extremely localized high temperature and pressure (>2,200 K, >0.3 GPa), and subsequent removal of laser irradiation led to fast cooling and pressure release that generated monolithic structure. By rational choice of MOF precursors, the particle sizes of MNPs were systematically tuned. Because of efficient light trap in the monolith, exceptional high solar absorptivity above 99% was realized, which guaranteed high solar-thermal conversion efficiency of 94% in solar-driven desalination.

Production of starch aerogel in form of monoliths and microparticles

Pea and amylomaize starches were used to produce aerogel in form of monoliths and microparticles. The formation of starch gel was investigated, and we showed that each starch needed a different pasting temperature for its complete dissolution. The gelation kinetics was investigated with oscillatory rheometry for both systems as a function of the starch concentration. The gelation and retrogradation temperature of the starch gel were varied and its impact on the final aerogel evaluated. The emulsion gelation was carried out batch wise in a stirred vessel with different impeller geometries, concentrations of surfactant (Span80 and PGPR) and stirring rates. A particle size prediction approach based on idealized flow (Couette, 2D hyperbolic and turbulent) during the emulsification was proposed. A semi-continuous set-up for the emulsion gelation was developed in which the emulsification occurs in a single pass through a colloid mill and the gelation is triggered in-line with a counter-current heat exchanger.Graphical abstract.

Effect of stiffeners in cleat angle based precast beam-column connections under reverse cyclic loading

Generally, wet connections are preferred for joining the beam and column elements of conventional precast concrete frame, which significantly affect the advantages of speedy and cost effective construction. Moreover, after an earthquake, the monolithic form of wet connections leads to the irreparable damages of structural elements. Thereby consumes significant downtime for the reuse of the building. In order to address these issues, the present study focuses on the performance of mechanical device (cleat angle) connections with the incorporation of damage avoidance and easily demountable systems when subjected to reverse cyclic loading. Three precast connections of one-third scaled model with parameters such as no stiffener, single stiffener and double stiffener in cleat angles were proposed. The performance of the precast connections was compared with that of the monolithic connection in terms of load-displacement behavior, load envelope curves, deformation capacity, secant stiffness, energy dissipation, equivalent viscous damping and stiffness degradation. From the test results, the cleat angle with stiffener (single and double) connections performed satisfactorily as compared to that of precast connection with unstiffened cleat angle. Overall, the cleat angle connection with single stiffener satisfied the criteria of speedy construction, easily demountable with minimal structural damage and recommended for the moderate seismic regions.

Preparation of carbon-based monolithic CO2 adsorbents with hierarchical pore structure

Various porous solid sorbents in the form of powder or monoliths have been developed over the last years, as a promising solution for reducing CO2 emissions. Although powder sorbents, due to higher porosities and efficient mass transport, exhibit higher capacities compared with monoliths, several factors limit their suitability for practical application. The most prominent is their low bulk density, which makes them difficult to handle and poses health risks due to dust inhalation. In this work, we prepared robust hierarchically porous carbon-based monoliths based on a simple three-step approach with the focus on combining efficient CO2 adsorption and transport with easy handling for practical applications. The approach is based on incorporation of polystyrene nanoparticles (PS NPs) and expanded graphite (EG) into a nitrogen-rich precursor, which is polymerized to form 3D monoliths. Incorporation of thermally unstable PS NPs or thermally stable EG enables us to control the formation of macropores during a precarbonization step, while variation of KOH concentration and mixing intensity during a subsequent activation step controls the formation of micropores. The resulting hierarchically porous monoliths with high nitrogen contents exhibited CO2 uptake capacities reaching 6.52 mmol g−1 at 273.15 K and 1 bar, which is among the highest reported for porous carbon monoliths. In addition, the materials also exhibited good reversibility of CO2 adsorption over several cycles with simple regeneration under mild conditions. Considering the high CO2 capture performance together with improvements in sorbent properties such as easy handling and reusability, the presented sorbents are promising candidates for practical applications.

Facile preparation of monolithic magnetic porous carbon acid catalysts via surface self-assembly method and their applications in conversion of xylose into furfural

Furfural is a versatile chemical derived from pentosane-rich agricultural and forestry residues. Considered as an important platform chemical, furfural can be converted into valuable chemicals and biofuels. The furfural production from xylose was produced through the hydrolysis and subsequent cyclodehydration reaction of xylose sugar catalyzed generally by various catalysts containing SO3H. Nevertheless, their tedious multi-step preparation and the final catalysts usually in the form of fine powder make them difficult to be separated from the liquid systems after use, leading to time consumption for the industrial scale production. In the this work, novel magnetic porous carbonaceous acid catalyst (SO3H-MPBG) in the form of monoliths have successfully been prepared using sugarcane bagasse as scaffold via a self-assembly surface coating method from phloroglucinol/glyoxylic acid precursors with soft-template F127 and Fe3+ as a source for magnetic iron particles. Then facile subsequent hydrothermal sulfonation with concentrated H2SO4 at 180°C resulted in magnetic mesoporous carbon bearing SO3H group (SO3H-MPBG). The SO3H-MPBG was characterized by various techniques including XRD, FT-IR, N2 sorption analysis, elemental analysis, and VSM. A SO3HMPBG showed strong magnetism due to the presence of iron magnetic particles and possessed a BET specific surface area of 252.96 m2/g. The sample showed acceptable xylose conversion (86.13%) and furfural selectivity (55.70%) when performed at 170°C for 3 h using γ-valerolactone (GVL) as a solvent. Besides, the catalyst was easily separated after the catalytic tests using a magnet, confirming its magnetic stability.

Thermographic Studies of Aerogel Composites

AbstractAerogels are regarded as the superior thermal insulating materials for wide range of temperatures, from cryogenic insulation, cold water diving garments to high temperature applications and even to defense and aerospace applications. For most of such applications, the aerogels are used in composite form rather than monolithic form as aerogels are fragile in nature due to its high porosity of up to 98%. These composites constitute aerogel infiltrated fiber mats to give flexibility, on the other hand, compromises on the insulation performance due to reinforcing aerogel with fibers that have comparatively higher thermal conductivity than silica aerogel. To increase the efficiency, density of the fiber mat needs to be reduced to incorporate higher loading of silica aerogel. Many techniques are being used to study the insulation performance of these composites. This paper presents about the study of insulation performance of fibre mats with different aerogel content and composition using a well-known thermography technique. The morphological, compositional, thermal and physical studies of the fiber mats and its composites using FESEM, EDAX, BET, thermal conductivity etc., are discussed.

Islamophobia in Reactionary News: Radicalizing Christianity in the United States

The accuracy and relevance of United States print news media has been called into question at increasing rates in the post-truth era. Conservatives, in particular, have long expressed concerns that mass and digital media censor conservative as well as Christian viewpoints while promoting a progressive and, more recently, pro-Muslim, platform. They have increasingly turned to alternative-right and alternative right-wing sources for news and discussion within what they deem to be unfiltered and unbiased networks. This article employs a mixed method approach of content and discourse analysis of sources from 1 January to 15 May of 2019 pertaining to discourse concerning the relationship between Christianity and Islam within and in response to articles in three such sources: Breitbart, The Federalist, and FrontPage Magazine. The role of these three websites is considered in the radicalization of those who aim to defend a monolithic form of Christianity rather than a particular Christian denomination or belief.

MECHANICAL AND TRIBOLOGICAL ANALYSIS OF MONOLITH AND COATING POLYETHERETHERKETONE

In this work, a comparative analysis of the micromechanical and tribological properties of polyetheretherketone (PEEK) in bulk and coating form was performed. The PEEK 708 coating was applied on a Ti6Al4V titanium alloy flat specimen using the electrophoretic deposition method. The micromechanical properties were determined through indentation tests performed using the Vickers method and scratch tests. Based on research work, the Vickers hardness (HV), elastic modulus (E), scratch hardness (HS), and Micro Mar Resistance (MMR) were determined. The tribological properties were defined by the coefficient of friction (fs and fw), which was obtained in scratch tests and ball-on-disk tests. The results of this research indicate, despite the slightly higher Vickers hardness (HV) of the PEEK 708 coating (HV=350 MPa, HS=300 MPa) relative to PEEK bulk (HV=300 MPa, HS=210 MPa), that there is an almost 40% difference between the scratch hardness (HS) values of these PEEK forms. It appears from the result analysis in this paper that testing methods to determine the micromechanical and tribological properties of PEEK in monolith form can be used for both PEEK coatings. Under certain test conditions, the impact of the substrate properties on the results of the PEEK 708 coating was not found.