Glass Surface Area Research Articles

The release behavior and in vitro osteogenesis of quercetin-loaded bioactive glass/hyaluronic acid/sodium alginate nanocomposite paste

Injectable pastes based on bioactive compounds and natural polymers are of interest in non-invasive bone surgeries. Several quantities of quercetin (100, 150, and 200 μM) were added to a sol-gel derived mesoporous bioactive glass. Injectable pastes based on quercetin-loaded bioactive glass, sodium alginate, and hyaluronic acid were prepared. Aggregated nanoparticles of bioactive glass and quercetin-loaded bioactive glass with mesoporous morphologies were confirmed by TEM and BET techniques. The quercetin release study was assessed in phosphate-buffered solution medium over 200 h and the obtained data were fitted by different eqs. A sustained release of quercetin was found, in which a better regression coefficient was achieved using Weibull equation. Human-derived mesenchymal stem cells were utilized to determine alkaline phosphatase activity and bone-related protein expression by western blotting and real-time PCR evaluations. Quercetin-loaded pastes increased the levels of alkaline phosphatase activity and the expression of Collagen-1, Osteopontin, Osteocalcin, and Runx2 proteins in a concentration-dependent manner. Due to the mesoporous architecture and high specific surface area of bioactive glass, the paste made of these particles and sodium alginate/hyaluronic acid macromolecules is appropriate matrix for quercetin release, resulting in promoted osteogenesis. The further in vivo studies can support the osteogenesis capacity of the quercetin-loaded paste.

Experimental investigation on the effective condenser glass area of solar still hybrid with photovoltaic cells

AbstractSolar desalination is a broad research field in the production of freshwater. The efficiency of the natural conversion solar desalination system is the only limitation to becoming its commercialization. It needs 1 m2 area for getting approximately 4.5 L of fresh water/day. In active methods 1 m2 area of solar still produce yield up to 10 L/day. In this study a new technology of fixing the photovoltaic cell (PV cells) in the natural passive solar still condenser glass to harvest both freshwater as well as electrical power generation is proposed. The experiments were carried out with conventional solar still of a glass surface area of 0.5 m2, still with an effective glass surface area of 0.3812 m2 and 36 PV cells taken up area of 0.1188 m2, and still with effective glass surface area of 0.3020 m2 and 60 PV cells taken up area of 0.198 m2. The study found that conventional solar still produced 2140 mL/day of yield, still with 36 PV cells produced 1380 mL/day of yield and 98 W of electrical power and still with 60 PV cells produced 840 mL/day of yield and 165 W of electrical power. This hybrid system, solar still with PV cells, produce both fresh water and electrical power. The fresh water yield and electrical power generation depends on the effective area of the solar still glass surface area and area occupied by PV cells attached to the solar still glass cover.

Impact of gold ion irradiation on the initial alteration rate of the International Simple Glass

This study addresses the impact of 7 MeV Au irradiation on the initial alteration rate of International Simple Glass (ISG), considered as a reference for nuclear glasses. This irradiation scenario simulates the effect of nuclear collisions of the recoil nuclei of α decays. In order to study the very first moments of glass alteration, non-irradiated and Au-ion irradiated ISG glass monoliths were altered in pure water at 90 °C, pH 9 and with a ratio of glass surface area to solution volume of 0.01 cm−1. Glass alteration was monitored by measuring the releases of the glass elements in solution by UV–visible spectrophotometry and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES). Under these alteration conditions, the releases of the elements in solution are congruent. The initial alteration rate was found to be (2.0 ± 0.8) times higher for the irradiated glass monoliths than for non-irradiated samples.

Investigation of silicic acid saturation and gel formation during ISG leaching: 180 days duration reaction at 90 °C

Currently, borosilicate glasses are utilised to immobilise highly radioactive waste. They are durable materials; however, they corrode in aqueous solutions, resulting in silica-rich alteration layers. This study employed the nuclear waste leaching tests (MCC-1, MCC-3) on International Simple Glass (ISG) samples. The corrosion rate in pure water and saturated water with respect to ISG corrosion products was investigated at an initial pH of 6.3 and a reaction temperature of 90 °C. For 3, 7, 14, 28, 90, and 180 days, batch experimental models with extremely high and very low glass surface area to volume (S/V) ratios were examined. The results showed that early saturation in the higher S/V system resulted in a ten order magnitude reduced corrosion rate compared to the lower S/V system. This emphasises the significance of saturation in achieving a reduced corrosion rate. This research proved the significant influence of the solution’s chemistry on the glass corrosion rate via pH and other chemical parameters.

The influences of substrates' physical properties on enzymatic PET hydrolysis: Implications for PET hydrolase engineering.

Plastic pollution in diverse terrestrial and marine environments is a widely recognised and growing problem. Bio-recycling and upcycling of plastic waste is a potential solution to plastic pollution, as these processes convert plastic waste into useful materials. Polyethylene terephthalate (PET) is the most abundant plastic waste, and this material can be degraded by a class of recently discovered bacterial esterase enzymes known as PET hydrolases (PETase). Investigations of the enzymatic hydrolysis of diverse PET molecules have clearly revealed that the biodegradability of various PET substrates depends on both their chemical structure and physical properties, including polymer length, crystallinity, glass transition temperature, surface area, and surface charge. This review summarises the known impacts of crystallinity and other physical properties on enzymatic PET hydrolysis.

Static dissolution experiments under hyperalkaline conditions with dispersed and confined SM539 glass

In the context of the geological disposal of vitrified radioactive waste, cracks are expected at the full scale of the glass blocks. To simulate glass alteration in cracks, static dissolution experiments were conducted with confined SM539 glass powder, at 30 °C in a synthetic young cementitious water. Short and long-term glass dissolution rates were determined and compared with those measured in similar experiments with dispersed glass powder. A long-term rate ~ 10 times lower was found, which might be due to a limited access of the solution to the glass surface area, resulting in a much higher local SA/V and faster increase of local concentrations of leached glass constituents, with possibly a lower local pH. In both types of experiments, the altered glass powder was characterised by XRD and SEM-EDX. Some glass particles showed the presence of an amorphous multi-layer and of fibrous and spherical secondary phases.Graphical abstract

Numericalinvestigationtodeterminetheoptimaltiltangleofsingleslopesolarstillduringsummerseason

Water, a basic human need can be purified by different techniques like membrane distillation, boiling and solar still. Among all types, solar still is considered to be the most economical and simpler one. In this study, the geometrical aspects of the solar still for Karachi by varying the tilt has been simulated. The study is conducted by varying the height and length of the solar still by keeping the constant glass surface area and by varying the height and length of the glass cover while keeping the constant basin area. The study is conducted between the time duration from 08:00 to 18:00 hours which is generally the sunshine duration for Karachi. The simulation results are verified with the experimental results which shows the good agreement with each other. For constant glass cover area, the maximum mass production of water has been observed at a tilt of 60° while for constant basin area the maximum tilt is observed for 24.8° equal to the latitude of Karachi. For both the cases, the maximum temperature of water and glass and maximum mass production of water is observed at around 13:00 hours.

Hydrothermal assisted conventional sol-gel method for synthesis of bioactive glass 70S30Cы

Bioactive glasses (Bioglasses) are widely synthesized by the conventional sol-gel method consisting of two main steps for sol and gel formation. However, the conversion from sol to gel requires a long time (5–7 days). In this study, the hydrothermal system was used to quickly synthesize the bioactive glass by reducing the conversion time from sol to gel. The hydrothermal assisted conventional sol-gel method was applied for synthesis of the bioactive glass 70SiO2–30CaO (mol%) (noted as 70S30C). The synthetic glass was investigated by the physical-chemical techniques. The ‘‘in vitro’’ experiments in SBF (Simulated Body Fluid) solution was also performed to evaluate the bioactivity of synthetic material. The obtained results show that the bioactive glass 70S30C was successfully elaborated by using the hydrothermal assisted conventional sol-gelmethod. The consuming time was reduced compared to the conventional method. The physical-chemical characterization confirmed that the synthetic glass is amorphous material with mesoporous structure consisting of interconnected particles.The specific surface area, pore volume and average pore diameter of synthetic glass were 142.8 m2/g, 0.52 cm3/g, and 19.1 nm, respectively. Furthermore, synthetic bioactive glass exhibited interesting bioactivity when immersed in simulated body fluid (SBF) solution for 1 days and good biocompatibility when cultured in cellular media.

Field measurement of indoor environment of a room with single-sided sliding glass opening

The indoor environment of a room is also affected by the opening type and configuration. The application of an opening in a building is mainly influenced by its aesthetic look rather than its environmental performance. Understanding of an opening’s impact towards the indoor environment is essential. The impact of a single-sided sliding glass opening to the indoor environment of a room discussed using field measurement. A room located in a two-storey detached house was selected. Total of ten days from 7 a.m. to 7 p.m., the sliding glass was slid to one side to allow natural ventilation into the room, hence, a cavity was created in between the two glasses. The results of the study indicated that high heat accumulation was detected at the glass surface area which faced the cavity and the air velocity in the room was found to be lower than the outdoor wind speed. This study provides important findings on the performance of a single-sided sliding glass opening and how it impacts the indoor environment of a room then help the building owner, designer, and people in the built environment industry to further understand the performance of sliding glass openings.

Kajian Pengaruh Ketebalan Kaca Evaporator Terhadap Energi Yang Diserap Kolektor Pada Proses Desalinasi Air Laut

The testing of desalination equipment is based on the increasing level of human need for the use of clean water. Improvement methods continue to be carried out with the aim of increasing the yield of clean water from desalination equipment. This research was conducted experimentally by providing a copper collector in a desalination device with a harpan to make it easier to absorb heat so that the water in the evaporator expands faster. By providing a variable difference in glass thickness, it is hoped that it can provide information that a good glass thickness can be applied to desalination equipment. The variation of the glass thickness is 4 mm and 5 mm with the same glass surface area. The results show that glass with a smaller thickness will make the desalination tool faster in absorbing heat energy. However, some conditions may also be considered to avoid damage to the glass. With the wind speed on the fourth day of testing which is 5.67 m/s and strong solar intensity reaching 397.14 W/m 2 , the energy absorbed by the collector reaches 3.72 kW/day on a glass thickness of 4 mm. Meanwhile, at a different thickness of 5 mm, the energy absorbed by the collector only reaches 2.72 kW/day. This shows that the difference in glass thickness plays a role in determining the occurrence of conduction heat transfer from outside the evaporator into the evaporator chamber.

Research of properties of edible packaging based on apple puree with addition of dried fruit and vegetable raw materials

A technology has been developed for the production of edible packaging based on applesauce with the addition of dried fruit and vegetable raw materials. As a result of research, a technology was developed for the production of edible glasses based on applesauce with the addition of dried apples, apricots, cranberries, bell peppers, tomatoes, carrots, and beets. A comparative assessment of the organoleptic and physico-chemical parameters of edible glasses based on applesauce with the addition of dried fruit and vegetable raw materials. Organoleptic indicators, humidity, water absorption, resistance to model liquids (distilled water with a temperature of 20–25 °C; distilled water with an initial temperature of 90–95 °C; 5 % aqueous solution of sodium chloride with a temperature of 20–25 °C; 5 % aqueous citric acid solution with a temperature of 20–25 °C), microscopic examination of the surface. Thus, as a result of a study of the organoleptic and physico-chemical parameters of edible packaging based on apple raw materials with the addition of dried fruit and vegetable raw materials, it was found that the most optimal physico-chemical indicators and mechanical properties of the glass are observed at the highest degree of grinding of dried fruit / vegetable additives and increase the degree of coverage of the surface area of the edible glass with the additive.

Glass surface micromachining with simultaneous nanomaterial deposition by picosecond laser for wettability control

Glass surface micromachining with simultaneous redeposition of nanomaterials in the vicinity of machined microscale trenches is achieved using a picosecond laser of visible wavelength in ambient air. After investigating the spatial distribution of redeposited nanomaterials by a unit discrete laser micromachining line, multi-line patterns machined with variable interline separations are characterized using optical and scanning electron microscopes. For large interline separations, laser machined debris was redeposited in the form of web-like nanofibrous aggregates with significant spatial variation in density. Reduced separations improved spatial uniformity but the increased material density induced noticeable conversion from web-like nanofibrous to fractal-like nano-cauliflower structures. In this way, picosecond laser machining processes enabled a single-step fabrication of multi-hierarchical micro/nanostructures on arbitrary glass surface areas with tunable nanomaterial structures. Based on the wetting behavior on patterned surfaces in ambient air by using the patterned surfaces as Wilhelmy plates in force-displacement measurements and in-situ optical microscope inspection, we find that contact angle hysteresis is suppressed for surfaces patterned with sufficiently small line separations due to the water infusion in the deposited nanomaterials. The studied laser processing method can be potentially employed for fast and effective fabrication of liquid infused surfaces with complex microscale patterns combined with controllable nanofeatures.

Characterization of Bioactive Glass Synthesized by Sol-Gel Process in Hot Water

Bioactive glass 70SiO2-30CaO (mol.%) was successfully synthesized by modified sol–gel in hot water without using an acid catalyst. TG-DSC analysis showed that the amorphous glass could be synthesized by sintering the sample at 700 °C for three hours. The N2 adsorption/desorption and TEM investigations highlighted that the synthetic glass had a mesoporous structure, consisting of spherical particles with sizes in the range of 11–20 nm. The specific surface area, pore volume, and average pore diameter of synthetic glass were 150.13 m2/g, 0.37 cm3/g, and 11.84 nm, respectively. Moreover, synthetic bioactive glass presented interesting bioactivity and good biocompatibility after in vitro experiments in simulated body fluid (SBF) and in cellular medium.

Green synthesis of bioactive glass 70SiO2-30CaO by hydrothermal method

Bioactive glass 70SiO2-30CaO (mol.%) was successfully synthesized by hydrothermal method following a green synthesis without any acid catalyst. XRD confirmed the amorphous property of prepared material. The N2 adsorption/desorption analysis highlighted the mesoporous structure of synthetic bioactive glass. FE-SEM and TEM images showed obvious aggregations of nearly spherical particles with sizes of 20–30 nm. The specific surface area, pore volume and average pore diameter of synthetic glass were 140.4 m2/g, 0.67 cm3/g, and 20.9 nm, respectively. Furthermore, prepared bioactive glass exhibit interesting bioactivity when immersed in simulated body fluid (SBF) for 7 days.

Volcanic glass leaching and the groundwater geochemistry on the semi-arid Atlantic island of Porto Santo

The groundwater chemistry of the semi-arid volcanic island of Porto Santo, part of the Madeira archipelago, Atlantic Ocean, was investigated. Generally, the groundwater was brackish, containing 2–10 mol % seawater. Groundwater with up to 20 mM alkalinity and a Na enrichment of up to 30 mM, as compared to the Na concentration predicted by the seawater Na/Cl ratio, was found in the main aquifer. Also notable are the high concentrations of F (up to 0.3 mM), B (up to 0.55 mM), As (up to 0.35 μM), all in excess of WHO recommendations, as well as up to 6 μM V. Geochemical modeling, using the PHREEQC code, was used to explore different scenarios that could explain the genesis of the observed bulk groundwater chemistry. First, a model for aquifer freshening with the displacement of resident seawater from the aquifer by infiltrating freshwater, was tested. This scenario leads to the development of NaHCO3 waters as observed in many coastal aquifers. However, the measured alkalinity concentration in the groundwater was far higher than the concentration predicted by the freshening model. In addition, the behavior of modelled pH and PCO2 were at variance with their distributions in the field data. The second model explored the possible effect of volcanic glass leaching on the groundwater chemistry. Using insight derived from studies of volcanic glass surface alteration as well as experimental work on water-volcanic glass interactions, a geochemical model was developed in which the exchange of H+ for Na+ on the volcanic glass surface is the main mechanism but the exchange of other cations on the volcanic glass surface is also included. The uptake of H+ by the glass surface causes the dissociation of carbonic acid, generating bicarbonate. This model is consistent with the local geology and the field data. It requires, however, volcanic glass leaching to occur in the unsaturated zone where there is an unlimited supply of CO2. The exchange reaction of H+ for Na+ is confined to the surface layer of volcanic glass as otherwise the process becomes limited by slow solid state diffusion of H+ into the glass and Na+ out of the glass. Therefore, volcanic ash deposits, with their high volcanic glass surface areas and matrix flow, are the aquifers where this type of high NaHCO3 waters can be expected, rather than in basalts, which predominantly feature fracture flow. The trace components F, B, As and V are believed to originate from hyaloclastites, consisting of predominantly (90%) of trachy-rhyolite volcanic glass. Although stratigraphically older than the main calcarenite aquifer, topographically they are often located at higher altitudes, above the phreatic level and located along the main recharge flow path. In addition, the semi-arid climate conditions provide a long groundwater residence time for the reactions as well as limited aquifer flushing.

The new idea for modification of the surface area of silicate glass

The paper presents a new and original method of modifying the surface layer of silicate glass by applying a coating produced from zirconium oxide–yttria-stabilized powder using the LPPS plasma method (low-pressure plasma spraying). This is a new approach and not found in both scientific literature and known technological solutions. The results of the work indicate that it is possible to produce the coatings of yttrium-stabilized zirconium oxide (YSZ) on the glass substrate. These coatings were made using the LPPS PS-PVD method and consist of fine YSZ crystals with spheroidal morphology. This gradient coating (FGM) has a thickness controlled from LPPS of several dozen to hundreds of nanometers. It effectively modifies the properties of the glass by introducing favorable stresses on the surface and therefore increases its hardness and tensile strength. At the same time, thermal properties of the glass were determined, which allowed to determine the temperature of heating the glass substrate necessary for the proper implementation of the oxide coating production process on this substrate by the LPPS method. The glass parameters achieved in the work are very promising and comparable with the characteristics of the best glasses currently used in optoelectronics, especially in the displays of mobile phones and solar cells.

Microcavity characteristics analysis of micro-shuttered organic light-emitting diodes

We demonstrated the control of the microcavity (MC) effect in micro-shuttered organic light-emitting diodes (OLEDs) with the introduction of an Ag striped pattern (ASP) layer between the organic layer and the indium zinc oxide layer. The ASP electrodes demonstrated high flexibility, conductivity, and transmittance. The optical and electrical properties of the OLED devices with micro-scale patterned metal electrodes with varying thicknesses and uncovered (open) area:entire glass surface area ratios (open ratios, ORs) were analyzed. The ASP OLEDs demonstrated high color purity and narrowed emission spectra because of the MC effect, increased light extraction by modulating the OR of the micro-shutter structure, and adjustability of the viewing angle distortion by controlling the OR. The ASP OLEDs exhibited maximum efficiency at the OR of 0.3 (Ag thickness; tAg = 15 nm) because of their optimum transmittance and conductivity. The viewing angle distortion decreased by approximately 60.3% with an increase in the OR from 0 to 0.7, as revealed by the changes in the color coordinates. The results showed that when deposited on flexible substrates, ASP electrodes can be used in flexible devices.

Diffusion models for the early-stage SON68 glass dissolution in a hyper-alkaline solution

Understanding the dissolution of nuclear waste glass in hyper-alkaline conditions is critical to predicting its safe disposal in cement-dominated disposal conditions. In this work, solution data from the early-stage SON68 glass dissolution in a KOH solution (pH 13.5 and 30 °C) were interpreted with models based on silicon (Si) diffusion controlled stoichiometric dissolution of the glass. The solution data show a linear increase of boron (B) concentration with the square root of time and a decrease of the glass dissolution rate with an increase in the ratio of glass surface area to solution volume (SA/V). Three models from the literature, based on either aqueous pore diffusion or solid diffusion with/without resistance of the surface boundary layer, can fit the evolution of solution concentrations for the major elements of the glass equally well. However, the fitted Si diffusion coefficients differ by several orders of magnitude. Since all these fitted diffusion coefficients are lower than diffusion coefficients generally reported for aqueous pore diffusion, they are more indicative of solid diffusion processes. These results show that even under such hyper-alkaline conditions where dissolution and precipitation reactions are usually considered to prevail over solid diffusion, solid diffusion can still be an important dissolution mechanism. Those two dissolution mechanisms do not necessarily contradict each other. It is postulated that incorporation of potassium (K) from the solution onto the glass surface provides a diffusion barrier against the release of glass components into the solution. Therefore, the early-stage glass dissolution rate under hyper-alkaline conditions should be lower than the predicted glass network dissolution rates extrapolated based simply on pH effects.

Stable and Prolonged Autonomous Oscillation in a Self-Oscillating Polymer Brush Prepared on a Porous Glass Substrate.

We developed an autonomous functional surface, named a "self-oscillating polymer brush surface", which exhibits swelling-deswelling of the modified polymer chains synchronized with the Belousov-Zhabotinsky (BZ) reaction. The grafted polymer chain is a random copolymer composed of thermoresponsive N-isopropylacrylamide, N-(3-aminopropyl)methacrylamide, and ruthenium tris(2,2'-bipyridine) [Ru(bpy)3]. To provide stable oscillations over a long period of time, suppression of the dilution of the BZ reactants inside the polymer surface and the increase in the amount of immobilized Ru(bpy)3 are important. Here, we modified the self-oscillating polymer brush on a porous glass substrate and characterized its dynamic behavior. The increased surface area of the porous glass allowed for an efficient introduction of the metal catalyst, which resulted in a stable BZ reaction observable by optical microscopy. Compared with an aqueous BZ solution and the self-oscillating polymer modified on a glass coverslip, the wave velocity and diffusion coefficient were significantly lower for the porous glass system, which suggested that the reaction-diffusion of the reactants was markedly different than those of the other two systems. Moreover, the wave velocity was unchanged on the porous glass system for 1 h, whereas that of the solution dropped by 30 μm s-1. Waveform analyses based on the Field-Körös-Noyes mechanism revealed that densely packed Ru(bpy)3 in the porous glass system affects the duration of the key processes in the BZ reaction. These findings can help with understanding the dynamic behavior of the self-oscillating polymer brush on a porous glass substrate. Stable self-oscillations on the polymer brush-grafted porous glass substrate will aid future applications such as mass transport systems.

The influence of cobalt incorporation and cobalt precursor selection on the structure and bioactivity of sol–gel-derived bioactive glass

Cobalt (Co) is a potential therapeutic ion used to enhance angiogenesis through a stabilizing effect on hypoxia-inducible factor 1 alpha (HIF-1α), and its incorporation into the structure of bioactive glass is a promising strategy to enable sustained local delivery of Co to a wound site or bone defect. Here Co-releasing bioactive glasses were obtained through the sol–gel method, comparing cobalt nitrate and cobalt chloride as precursors. The effect of using different Co precursors on the sol–gel synthesis and in the obtained bioactive glass structure, chemical composition, morphology, dissolution behaviour, hydroxycarbonate apatite (HCA) layer formation was investigated. When the chloride salt was used as Co precursor, evidence of crystalline cobalt (II, III) oxide (Co3O4) phase formation was found, along with the presence of Co3+ species as evaluated by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), whereas an amorphous glass containing mainly Co2+ species was obtained when the nitrate salt was the Co source. The presence of a crystalline phase decreased the surface area and pore volume of the final glass, consequently reducing the Co-release rate. Evidence of HCA layer formation after immersion in simulated body fluid (SBF) was still found when different precursors were used, although the rate of formation was reduced by the presence of Co. Therefore, this study showed that Co incorporation and the proper selection of the precursor could affect the final material structure, and properties, and should be considered when designing new bioactive glass compositions for tissue engineering applications.