602 research outputs found
Fabrication and environmental applications of glass microspheres: A review
No full textContinuous technological progress is required to improve production efficiency and environmental quality while maintaining economic competitiveness. A non-negligible contribution to some of these goals can be achieved through the production of glass microspheres for a wide range of applications. The fabrication techniques of glass microspheres including flame synthesis, liquid droplet method, dried gel process and electrical arc process are surveyed. The mechanisms of the recent syntheses of porous and hollow glass microspheres are also reviewed. Glass microspheres are a promising substrate for titania coatings which can be used in water purification and self-cleaning systems. Due to their high mechanical strength and low thermal conductivity, they can also be applied in cementitious and insulating products. Glass microspheres can carry hydrogen gas at pressures of up to 150 MPa. In addition, they can enhance the quality of lead-acid batteries by decreasing the critical volume fraction..
Alkali activation-induced cold consolidation of waste glass: Application in organic-free direct ink writing of photocatalytic dye destructors
No full textAdditive manufacturing, with its ability to assemble a variety of materials in complex and customized architectures, is developing rapidly. The integration of technologies and materials into a sustainable production, however, is still challenging. The present investigation offers new functional glass-based products, from nearly room temperature processing, based on direct ink writing (DIW) of pastes from ‘light’ alkali activation (2.5 M NaOH) of pharmaceutical glass waste, added with 20 wt% of TiO2 nanoparticles. The inks were refined by the inclusion of porous glass microspheres (PGMs, 20–30 wt%), previously fabricated from fiber glass waste. Printed scaffolds, stabilized by simple drying (i.e. ‘unfired’), were successfully applied in the photodegradation of methylene blue. The degradation efficiency reached 100% within 75 min, and the 3D-printed composites could be easily separated from the solution for subsequent reuse. The degradation efficiency declined only by 7.5%, after 5 cycles
Upcycling waste derived glass into high-performance photocatalytic scaffolds by alkali activation and direct ink writing
No full textNovel and eco-friendly solutions are extensively needed for wastewater treatment. This work capitalizes on the combination of waste vitrification and additive manufacturing to produce an efficient photocatalyst for the specific purpose. Fine powders of waste-derived glass, containing Fe3O4 inclusions, by simple suspension (for a solid loading of 65 wt %) in alkaline solution (5 M NaOH), were transformed into pastes for direct ink writing. 3D-printed reticulated scaffolds were stabilized by the progressive hardening of a zeolite-like gel, formed by glass/solution interaction, at nearly room temperature. The printed scaffolds were successfully tested for the removal of methylene blue, realized by combining the high sorption capacity of the gel with the catalytic activity of magnetite inclusions, under UV light. A complete degradation of methylene blue is achieved by 90 min exposure, comparing favorably with other reported photocatalytic materials, requiring from 60 to 360 min. The photocatalytic activity was tested for several cycles, with no significant degradation. In other words, a waste-derived material can be reused for multiple times, to remediate wastewaters, with evident benefits on waste minimization
Enhanced methylene blue adsorption by double alkali activation of highly porous glass microspheres prepared from waste glass
No full textThe remediation of water from organic pollutants, such as dyes and related compounds and the reuse of discarded glasses, represents fundamental challenges in highly industrialized countries. Porous glass microspheres have been proposed as efficient adsorbents in wastewater treatment, but their real application is problematic, especially from the perspective of their reuse and recycling. For the first time, the present paper describes the process of preparation and use of highly porous bodies with a specific surface area of nearly 20 m2/g fabricated from alkali activated glass microspheres and applicable for the removal of methylene blue as a model organic dye from wastewater. Alkali activation is applied both as an intermediate step (using 9 M KOH) for the conversion of waste glass into porous microspheres by flame spheroidization process, and as a final step (using 2.5 M NaOH), facilitating low temperature consolidation of the microspheres, and their transformation into porous structures. The experimental adsorption capacity of porous glass microspheres pellet was 122 mg/g. The high correlation coefficient indicates the applicability of Langmuir isotherm adsorption model
Evaluation of genetic diversity within different rabbit (Oryctolagus cuniculus) genotypes utilizing start codon targeted (SCoT) and inter-simple sequence repeat (ISSR) molecular markers
No full textThis work aimed at studying the genetic diversity among different rabbit genotypes reared in Egypt by two different molecular markers (start codon targeted, SCoT, and inter-simple sequence repeat, ISSR) to improve breeding strategies. Five different groups of rabbits were used Gabali (Gab), New Zealand white (NZW), Californian (Cal), Rex, and Papillon (Pap). DNA was extracted and analyzed using SCoT and ISSR-PCR, and the obtained fragments were analyzed. Six SCoT primers scored 60 bands with 78.33 % polymorphism; primer SCoT 6 was the most polymorphic marker with 92.31 % polymorphism, while SCoT 5 was the lowest with 60 %. A dendrogram based on SCoT-PCR revealed that the Rex breed was the most genetically different. Seven ISSR primers gained 56 bands in total with 49.762 % polymorphism. ISSR 4 was the most polymorphic primer that detected 75 % of polymorphism, while ISSR 6 was not able to detect any polymorphism. It was suggested that the SCoT markers may be more effective than ISSR for differentiating and identifying the genetic variations within investigated breeds. Also, the usage of molecular markers of SCoT and ISSR may be more proper for calculating genetic diversity and common ancestry among tested rabbit breeds. Furthermore, evaluating genetic variability is important for enhancing existing breeds' adaptation to ecological alterations and crucial for preservation or breeding purposes
Additive manufacturing of scaffolds from porous glass microspheres via masked stereolithography: Printing challenges and sustainable applications
No full textAdditive manufacturing techniques, particularly masked stereolithography (MSLA), enable the creation of intricate and precise porous glass structures. However, preserving slurry stability remains a significant challenge for MSLA. For the first time, this study offers a novel approach to printing highly porous glass microspheres by addressing particle aggregation and sedimentation issues. Particle settling and separation are effectively avoided by coating the porous glass microspheres with polyethylene glycol (PEG) before combining them with photocurable resin. Using this approach, scaffolds with a diamond-shaped cellular structure and 90 % open porosity were fabricated via MSLA. Furthermore, incorporating 7.5 wt% titania nanoparticles enabled the fabrication of 3D composite structures with photocatalytic activity. The printed scaffolds, consisting of pure porous glass microspheres and porous glass microspheres containing titania, were assessed for their capacity to adsorb and photodegrade methylene blue dye. The addition of titania nanoparticles significantly enhanced photocatalytic performance, increasing dye remediation efficiency from 74 % to 100 %. The findings demonstrate the ability of 3D printing technology to repurpose and improve the usefulness of discarded glass, providing a sustainable and effective method for addressing a variety of environmental issues
Different Acid Systems Interactions with Sand and Ceramic Proppants Used in Gravel-Packed and Fractured Wells
No full textProppants are solid particles, extensively used in hydraulic fracturing operations. These materials possess specific mechanical strength indispensable in keeping induced fractures open, resulting in up-surged well production.
Proppants have different parameters including density, mechanical strength, internal porosity, shape, sieve distribution, and most importantly acid resistance.
The acid resistance of the fracturing proppants, defined as the stability and suitability of proppants when they come into contact with different acids, is an important property. Numerous acids are used during the hydraulic fracturing process to remove the scale and clays affecting the fracture conductivity. Inopportunely, these acids adversely affect the proppants already existing in the fracture. The industry measures the acid solubility of proppants according to the API RP 19C/ISO 13503-2 standard. However, it fails to give any guidance on the anticipated final effect of acid dissolution on the mechanical performance of the tested proppants.
This study investigates different factors affecting the interactions of different acid systems with sand and ceramic proppants under downhole conditions. Solubility experiments were conducted using translucent and aging cells at temperatures up to 350°F. The effects of varying acid system, temperature, soaking time, static, and dynamic conditions were examined. The supernatant of solubility tests was analyzed with Fluorine Nuclear Magnetic Resonance (19F-NMR) to identify the reaction products. Total key cations’ concentrations were measured using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Proppants were then analyzed by X-ray fluorescence (XRF) and X-ray diffraction (XRD) to detect their mineral composition. After performing solubility tests, the residual solids were then dried and analyzed using Scanning Electron Microscopes (SEMs) with Energy Dispersive X-ray Spectroscopy (EDS) capabilities. Moreover, the effects of acid dissolution on the mechanical performance of proppants were also tested using an automated load frame.
Experimental results show that monocrystalline sand proppants are soluble in regular mud acid (12.0 wt% HCl, 3.0 wt% HF), with a maximum recorded solubility of 10.0 wt%. Clay-based ceramic proppants are also soluble in mud acid, with much higher acid solubility compared to sand proppants. Proppant pack shows more compaction for clay-based proppants than that of sand proppants prior to and after acid exposure. Bauxitic ceramic proppants have a minimal solubility of 0.5 wt% in 10.0 wt% HCl. The proppant, however, is readily soluble in different mud acid solutions, reaching up to 56.0 wt% dissolution in some extreme cases. The higher solubility of ceramic proppants is attributed to HF attack at the grain boundaries.
Understanding the effects of various acids on natural and synthetic proppants will improve production capabilities by promoting the design of acidizing regimens recommended during hydraulic fracturing operations
Sensor network for museum environmental monitoring
No full textMuseum environmental monitoring is an important
issue for the artifact conservation. Many solutions have been
proposed to tackle this problem, but the museum constraints
prevent an easy application in several cases, especially if the
monitoring has to be performed in museums where an environmental
control system has been already installed. This paper
describes a simple though powerful solution, which complies with
most of the common constraints and which is based on small
sensors implementing a BT-LE wireless protocol coupled with
a receiving architecture. The sensing nodes have dimensions of
few centimeters, do not require cabling and power supply, and
can work unattended for several years. Data are collected by
a receiving architecture, which can work either on-line, with
immediate data delivery, or off-line when an Internet connection
is not available. Users can browse the measurements by using
their smart-phones from any place and can download the data
on their personal computer. In addition they can browse locally
the data also in the absence of any data connection, such as in
the case of remote and or recessed sites. The proposed solution
has been deployed in three museums, also in the basements, and
in an ancient building proving its flexibility and capability to be
adapted to the different conditions
EACVI communication paper: First international young dedicated multimodal cardiovascular imaging simulation education event organized by the ESC
No full textNeochrysocharis formosus Westwood
No full textNeochrysocharis formosus (Westwood) Material examined. 2 ♀, Kom Osheim (Fayoum), 29 ° 34 '07"N, 30 ° 54 ' 26 "E, Malaise trap, 29–31.v. 2013; 1 ♀, El-Heiz (Ein Eleza, Bahariya Oasis), 28 °01' 34 "N, 28 ° 38 ' 20 "E, swept on Medicago sativa, 26.x. 2013 (leg. Usama Abu El-Ghiet); 2 ♀, Kafr Salem (El Gharbiya), 30 ° 43 ' 52 "N, 34 ° 18 '07"E, Malaise trap, 3–6.x. 2014; 1 ♀, 1 ♂, Kafr Salem (El Gharbiya), 30 ° 43 ' 52 "N, 34 ° 18 '07"E, Malaise trap, 3–6.x. 2014 (leg. Ahmed M. Soliman); 1 ♂, Botanical Gaden (Aswan), 24 °05' 38 "N, 32 ° 53 ' 13 "E, 11.iii. 2014 (by sweeping) (leg. Yusuf Edmardash); 2 ♀, Burullus (Kafr El Sheikh), 31 ° 33 ' 58 "N, 31 °07' 53 "E, swept on grasses, 26.x. 2014 (leg Yusuf Edmardash & Mustafa Mahmoud). Previous records from Egypt. Al Ameria district (Alexandria) (31 °01' 24 "N, 29 ° 49 ' 48 "E) (Doğanlar & Elsayed 2015). Distribution. Cosmopolitan (except Australia). Host records. In Egypt, it has been reared from galls of Asphondylia punica Marchal (Diptera: Cecidomyiidae) on the stems and flower buds of the Mediterranean saltbush, Atriplex halimus (Doğanlar & Elsayed 2015).Published as part of Gadallah, Neveen S., Yefremova, Zoya A., Yegorenkova, Ekaterina N., Soliman, Ahmed M., Abu El-Ghiet, Usama M. & Edmardash, Yusuf A., 2015, A review of the family Eulophidae (Hymenoptera: Chalcidoidea) of Egypt, with thirty three new records in Zootaxa 4058 (1), DOI: 10.11646/zootaxa.4058.1.3, http://zenodo.org/record/23657
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