scholarly journals Alumina-Doped Silica Aerogels for High-Temperature Thermal Insulation

Gels ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 122
Author(s):  
Yu Wu ◽  
Xiaodong Wang ◽  
Lin Liu ◽  
Ze Zhang ◽  
Jun Shen
Keyword(s):  
Heat Treatment ◽  
High Temperature ◽  
Thermal Insulation ◽  
Large Scale ◽  
Low Cost ◽  
Linear Shrinkage ◽  
Silica Aerogels ◽  
Hydroxyl Groups ◽  
Scale Production ◽  
Α Al2o3

In this study, we used two methods to prepare alumina-doped silica aerogels with the aim of increasing the thermal stability of silica aerogels. The first method was physical doping of α-Al2O3 nano powders, and the second method was to create a chemical compound via the co-precursor of TEOS and AlCl3·6H2O in different proportions. The shrinkage, chemical composition, and specific surface area (SSA) of samples after heating at different temperatures were analyzed. Our results show that the silicon hydroxyl groups of samples derived from AlCl3·6H2O gradually decreased and nearly disappeared after heating at 800 °C, which indicates the complete dehydration of the silicon hydroxyl. Thus, the samples exhibited a large linear shrinkage and decreased SSA after high-temperature heat treatment. By contrast, samples doped with α-Al2O3 powders retained abundant silicon hydroxyl groups, and the 6.1 wt.% α-Al2O3-doped sample exhibited the lowest linear shrinkage of 11% and the highest SSA of 1056 m2/g after heat treatment at 800 °C. The alumina-doped silica aerogels prepared using a simple and low-price synthesized method pave the way for the low-cost and large-scale production of high-temperature thermal insulation.

Clad Metal Strips and Foils Engineered for High-Temperature Performance

2005 ◽  
Author(s):  
L. Chen ◽  
P. J. Maziasz
Keyword(s):  
Corrosion Resistance ◽  
High Temperature ◽  
Gas Turbines ◽  
Large Scale ◽  
Catalytic Converter ◽  
Low Cost ◽  
High Temperature Strength ◽  
Scale Production ◽  
Roll Bonding ◽  
Clad Metals

In order to increase the engine efficiencies in small size gas turbines and microturbines, recuperators with operating temperatures over 700°C have been developed and evaluated recently. This provides challenges to materials developers and researchers for new solutions in high temperature alloys. The alloys for recuperators should have good performance in high temperature strength, creep resistance and corrosion resistance between 700∼750°C, while their cost should be kept within a reasonable range. Traditionally, clad metals by roll bonding provide both functionality and low cost solutions in demanding corrosion resistance applications and their manufacturing has been well established in large scale production. In this work, cladding technologies, particularly roll bonding, have been reviewed. Two clad metal system approaches, e.g. simple clad metal and clad metal with diffusion alloying, applied for high temperature applications are discussed. The examples of both approaches (SOFC interconnect development, catalytic converter substrate) are presented with test results. Finally, the paper presents a preliminary feasibility study of clad metal for recuperators.

scholarly journals Effects of Ag contents on the microstructure and SERS performance of self-grown Ag nanoparticles/Mo–Ag alloy films

2020 ◽  
Vol 9 (1) ◽  
pp. 751-759 ◽  
Author(s):  
Xinxin Lian ◽  
Yuanjiang Lv ◽  
Haoliang Sun ◽  
David Hui ◽  
Guangxin Wang
Keyword(s):  
Ag Nanoparticles ◽  
Large Scale ◽  
Low Cost ◽  
Film Surface ◽  
Time Domain Analysis ◽  
Alloy Film ◽  
Scale Production ◽  
Alloy Films ◽  
Surface Enhanced Raman ◽  
Ag Film

AbstractAg nanoparticles/Mo–Ag alloy films with different Ag contents were prepared on polyimide by magnetron sputtering. The effects of Ag contents on the microstructure of self-grown Ag nanoparticles/Mo–Ag alloy films were investigated using XRD, FESEM, EDS and TEM. The Ag content plays an important role in the size and number of uniformly distributed Ag nanoparticles spontaneously formed on the Mo–Ag alloy film surface, and the morphology of the self-grown Ag nanoparticles has changed significantly. Additionally, it is worth noting that the Ag nanoparticles/Mo–Ag alloy films covered by a thin Ag film exhibits highly sensitive surface-enhanced Raman scattering (SERS) performance. The electric field distributions were calculated using finite-difference time-domain analysis to further prove that the SERS enhancement of the films is mainly determined by “hot spots” in the interparticle gap between Ag nanoparticles. The detection limit of the Ag film/Ag nanoparticles/Mo–Ag alloy film for Rhodamine 6G probe molecules was 5 × 10−14 mol/L. Therefore, the novel type of the Ag film/Ag nanoparticles/Mo–Ag alloy film can be used as an ideal SERS-active substrate for low-cost and large-scale production.

scholarly journals Thermoelectric Performance of Mechanically Mixed BixSb2-xTe3—ABS Composites

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1706
Author(s):  
Zacharias Viskadourakis ◽  
Argiri Drymiskianaki ◽  
Vassilis M. Papadakis ◽  
Ioanna Ioannou ◽  
Theodora Kyratsi ◽  
...  
Keyword(s):  
Polymer Composites ◽  
Large Scale ◽  
Low Cost ◽  
Acrylonitrile Butadiene Styrene ◽  
Thermoelectric Performance ◽  
Scale Production ◽  
Bismuth Antimony Telluride ◽  
Mechanical Mixing ◽  
Large Scale Production ◽  
Bi Doping

In the current study, polymer-based composites, consisting of Acrylonitrile Butadiene Styrene (ABS) and Bismuth Antimony Telluride (BixSb2−xTe3), were produced using mechanical mixing and hot pressing. These composites were investigated regarding their electrical resistivity and Seebeck coefficient, with respect to Bi doping and BixSb2-xTe3 loading into the composite. Experimental results showed that their thermoelectric performance is comparable—or even superior, in some cases—to reported thermoelectric polymer composites that have been produced using other complex techniques. Consequently, mechanically mixed polymer-based thermoelectric materials could be an efficient method for low-cost and large-scale production of polymer composites for potential thermoelectric applications.

scholarly journals Extensive Screening of Green Solvents for Safe and Sustainable UiO-66 Synthesis

2020 ◽  
Author(s):  
Diletta Morelli Venturi ◽  
Filippo Campana ◽  
Fabio Marmottini ◽  
Ferdinando Costantino ◽  
Luigi Vaccaro
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Dimethyl Formamide ◽  
Scale Production ◽  
Green Solvents ◽  
High Quality ◽  
Color Code ◽  
Large Scale Production ◽  
Metal Organic

<p>Zirconium based Metal-Organic Framework UiO-66 is to date considered one of the benchmark compound among stable MOFs and it has attracted a huge attention for its employment in many strategic applications. Large scale production of UiO-66 for industrial purposes requires the use of safe and green solvents, fulfilling the green chemistry principles and able to replace the use of <i>N,N</i>-Dimethyl-Formamide (DMF), which, despite its toxicity, is still considered the most efficient solvent for obtaining UiO-66 of high quality. Herein we report on a survey of about 40 different solvents with different polarity, boiling point and acidity, used for the laboratory scale synthesis of high quality UiO-66 crystals. The solvents were chosen according the European REACH Regulation 1907/2006 among those having low cost, low toxicity and fully biodegradable. Concerning MOF synthesis, the relevant parameters chosen for establishing the quality of the results obtained are the degree are the crystallinity, microporosity and specific surface area, yield and solvent recyclability. Taking into account also the chemical physical properties of all the solvents, a color code was assigned in order to give a final green assessment for the UiO-66 synthesis. Defectivity of the obtained products, the use of acidic modulators and the use of alternative Zr-salts have been also taken into consideration. Preliminary results lead to conclude that GVL (γ-valerolactone) is among the most promising solvents for replacing DMF in UiO-66 MOF synthesis. </p>

scholarly journals Low-cost Large Scale Vermicompost Unit

2021 ◽  
Vol 2115 (1) ◽  
pp. 012026
Author(s):  
Sonam Solanki ◽  
Gunendra Mahore
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Small Scale ◽  
Scale Production ◽  
Key Innovation ◽  
Main Challenge ◽  
Long Run ◽  
Large Scale Production ◽  
Term Maintenance

Abstract In the current process of producing vermicompost on a large-scale, the main challenge is to keep the worms alive. This is achieved by maintaining temperature and moisture in their living medium. It is a difficult task to maintain these parameters throughout the process. Currently, this is achieved by building infrastructure but this method requires a large initial investment and long-run maintenance. Also, these methods are limited to small-scale production. For large-scale production, a unit is developed which utilises natural airflow with water and automation. The main aim of this unit is to provide favourable conditions to worms in large-scale production with very low investment and minimum maintenance in long term. The key innovation of this research is that the technology used in the unit should be practical and easy to adopt by small farmers. For long-term maintenance of the technology lesser number of parts are used.

scholarly journals Extensive Screening of Green Solvents for Safe and Sustainable UiO-66 Synthesis

2020 ◽  
Author(s):  
Diletta Morelli Venturi ◽  
Filippo Campana ◽  
Fabio Marmottini ◽  
Ferdinando Costantino ◽  
Luigi Vaccaro
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Metal Organic Framework ◽  
Dimethyl Formamide ◽  
Scale Production ◽  
Green Solvents ◽  
High Quality ◽  
Color Code ◽  
Large Scale Production ◽  
Metal Organic

<p>Zirconium based Metal-Organic Framework UiO-66 is to date considered one of the benchmark compound among stable MOFs and it has attracted a huge attention for its employment in many strategic applications. Large scale production of UiO-66 for industrial purposes requires the use of safe and green solvents, fulfilling the green chemistry principles and able to replace the use of <i>N,N</i>-Dimethyl-Formamide (DMF), which, despite its toxicity, is still considered the most efficient solvent for obtaining UiO-66 of high quality. Herein we report on a survey of about 40 different solvents with different polarity, boiling point and acidity, used for the laboratory scale synthesis of high quality UiO-66 crystals. The solvents were chosen according the European REACH Regulation 1907/2006 among those having low cost, low toxicity and fully biodegradable. Concerning MOF synthesis, the relevant parameters chosen for establishing the quality of the results obtained are the degree are the crystallinity, microporosity and specific surface area, yield and solvent recyclability. Taking into account also the chemical physical properties of all the solvents, a color code was assigned in order to give a final green assessment for the UiO-66 synthesis. Defectivity of the obtained products, the use of acidic modulators and the use of alternative Zr-salts have been also taken into consideration. Preliminary results lead to conclude that GVL (γ-valerolactone) is among the most promising solvents for replacing DMF in UiO-66 MOF synthesis. </p>

A Ceramic Tubular Probe For Online Substance Concentration Measurement, Manufactured By Ceramic Injection Molding

2012 ◽  
Vol 2012 (1) ◽  
pp. 000604-000608
Author(s):  
Matthias Hartmann ◽  
Bertram Schmidt
Keyword(s):  
Injection Molding ◽  
Zirconium Oxide ◽  
Large Scale ◽  
Low Cost ◽  
Tetragonal Zirconia ◽  
Scale Production ◽  
Ceramic Injection Molding ◽  
Substance Concentration ◽  
Sensor Effect ◽  
Concentration Measurements

The current research presents recent respective to the work development of a ceramic tubular probe for online substance concentration measurements. The aim was to develop a robust and acid-resistant sensor device, which can be easily included in existing procedural pipeline systems. To archive those goals a lot of factors had to be checked. For the substance concentration measurements a capacitive sensor effect was chosen. With this method even low substance concentrations down to one-tenth of a per cent can be indentified. For the package material zirconium oxide (tetragonal zirconia polycrystal – TZP) was used. Zirconium oxide is a technical ceramic which is wear-resistant, acid-resistant, has a low thermal conductivity, is electrically isolating and can be uses in a ceramic injection molding (CIM) process. In the phase of the sensor design process multiple geometries for the sensor effect and integration space for the evaluation electronics had to be considered. A standardized DN 10 DIN 32676 flanged joint was also added for an unproblematic connection to the pipelines. All these needed geometries had to be integrated into one ceramic element. As a result of these requirements a 3D CAD model of the sensor element was designed. The CAD-file has shown that there was only the CIM technology left to comprehend developed sensor geometry. CIM is a low cost process for large-scale production which is distinguished by high size accuracy. In the CIM process the material shrinkage, this is caused by the needed debindering and sintering steps, had to be considered. The developed ceramic tubular probe was successfully tested in multiple fluidic systems. It has left the test phase and is now ready for maturity phase.

scholarly journals Continuous, Strong, Porous Silk Firoin-Based Aerogel Fibers toward Textile Thermal Insulation

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1899 ◽  
Author(s):  
Haiwei Yang ◽  
Zongqian Wang ◽  
Zhi Liu ◽  
Huan Cheng ◽  
Changlong Li
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Hollow Fiber ◽  
High Performance ◽  
Large Scale ◽  
Low Density ◽  
Potential Candidate ◽  
Scale Production ◽  
Insulation Material ◽  
High Porosity

Aerogel fiber, with the characteristics of ultra-low density, ultra-high porosity, and high specific surface area, is the most potential candidate for manufacturing wearable thermal insulation material. However, aerogel fibers generally show weak mechanical properties and complex preparation processes. Herein, through firstly preparing a cellulose acetate/polyacrylic acid (CA/PAA) hollow fiber using coaxial wet-spinning followed by injecting the silk fibroin (SF) solution into the hollow fiber, the CA/PAA-wrapped SF aerogel fibers toward textile thermal insulation were successfully constructed after freeze-drying. The sheath (CA/PAA hollow fiber) possesses a multiscale porous structure, including micropores (11.37 ± 4.01 μm), sub-micron pores (217.47 ± 46.16 nm), as well as nanopores on the inner (44.00 ± 21.65 nm) and outer (36.43 ± 17.55 nm) surfaces, which is crucial to the formation of a SF aerogel core. Furthermore, the porous CA/PAA-wrapped SF aerogel fibers have many advantages, such as low density (0.21 g/cm3), high porosity (86%), high strength at break (2.6 ± 0.4 MPa), as well as potential continuous and large-scale production. The delicate structure of multiscale porous sheath and ultra-low-density SF aerogel core synergistically inhibit air circulation and limit convective heat transfer. Meanwhile, the high porosity of aerogel fibers weakens heat transfer and the SF aerogel cellular walls prevent infrared radiation. The results show that the mat composed of these aerogel fibers exhibits excellent thermal insulating properties with a wide working temperature from −20 to 100 °C. Therefore, this SF-based aerogel fiber can be considered as a practical option for high performance thermal insulation.

scholarly journals Biomass and lipid induction strategies in microalgae for biofuel production and other applications

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Hossein Alishah Aratboni ◽  
Nahid Rafiei ◽  
Raul Garcia-Granados ◽  
Abbas Alemzadeh ◽  
José Rubén Morones-Ramírez
Keyword(s):  
Lipid Content ◽  
Large Scale ◽  
Fossil Fuels ◽  
Low Cost ◽  
Lipid Production ◽  
Arable Land ◽  
Economic Cost ◽  
Biofuel Production ◽  
Scale Production ◽  
Microalgae Biomass

Abstract The use of fossil fuels has been strongly related to critical problems currently affecting society, such as: global warming, global greenhouse effects and pollution. These problems have affected the homeostasis of living organisms worldwide at an alarming rate. Due to this, it is imperative to look for alternatives to the use of fossil fuels and one of the relevant substitutes are biofuels. There are different types of biofuels (categories and generations) that have been previously explored, but recently, the use of microalgae has been strongly considered for the production of biofuels since they present a series of advantages over other biofuel production sources: (a) they don’t need arable land to grow and therefore do not compete with food crops (like biofuels produced from corn, sugar cane and other plants) and; (b) they exhibit rapid biomass production containing high oil contents, at least 15 to 20 times higher than land based oleaginous crops. Hence, these unicellular photosynthetic microorganisms have received great attention from researches to use them in the large-scale production of biofuels. However, one disadvantage of using microalgae is the high economic cost due to the low-yields of lipid content in the microalgae biomass. Thus, development of different methods to enhance microalgae biomass, as well as lipid content in the microalgae cells, would lead to the development of a sustainable low-cost process to produce biofuels. Within the last 10 years, many studies have reported different methods and strategies to induce lipid production to obtain higher lipid accumulation in the biomass of microalgae cells; however, there is not a comprehensive review in the literature that highlights, compares and discusses these strategies. Here, we review these strategies which include modulating light intensity in cultures, controlling and varying CO2 levels and temperature, inducing nutrient starvation in the culture, the implementation of stress by incorporating heavy metal or inducing a high salinity condition, and the use of metabolic and genetic engineering techniques coupled with nanotechnology.

scholarly journals Towards High Performance Chemical Vapour Deposition V2O5 Cathodes for Batteries Employing Aqueous Media

Molecules ◽  
2020 ◽  
Vol 25 (23) ◽  
pp. 5558
Author(s):  
Dimitra Vernardou ◽  
Charalampos Drosos ◽  
Andreas Kafizas ◽  
Martyn E. Pemble ◽  
Emmanouel Koudoumas
Keyword(s):  
Energy Storage ◽  
High Performance ◽  
Large Scale ◽  
Electrode Materials ◽  
Low Cost ◽  
Aqueous Media ◽  
Chemical Vapour ◽  
Cost Effective ◽  
Scale Production ◽  
Environmentally Safe

The need for clean and efficient energy storage has become the center of attention due to the eminent global energy crisis and growing ecological concerns. A key component in this effort is the ultra-high performance battery, which will play a major role in the energy industry. To meet the demands in portable electronic devices, electric vehicles, and large-scale energy storage systems, it is necessary to prepare advanced batteries with high safety, fast charge ratios, and discharge capabilities at a low cost. Cathode materials play a significant role in determining the performance of batteries. Among the possible electrode materials is vanadium pentoxide, which will be discussed in this review, due to its low cost and high theoretical capacity. Additionally, aqueous electrolytes, which are environmentally safe, provide an alternative approach compared to organic media for safe, cost-effective, and scalable energy storage. In this review, we will reveal the industrial potential of competitive methods to grow cathodes with excellent stability and enhanced electrochemical performance in aqueous media and lay the foundation for the large-scale production of electrode materials.

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