Morphologically stable and controlled shape of CsPbBr3 perovskite nanoparticle synthesized at room temperature with curing time

2021 ◽  
Author(s):  
Azzah Dyah Pramata ◽  
Diah Susanti ◽  
Haniffudin Nurdiansah
Keyword(s):  
Room Temperature ◽  
Curing Time

Effect of Curing Regimes on Metakaolin Geopolymer Pastes Produced from Geopolymer Powder

2012 ◽  
Vol 626 ◽  
pp. 931-936 ◽  
Author(s):  
Liew Yun Ming ◽  
Kamarudin Hussin ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Mohammed Binhussain ◽  
Luqman Musa ◽  
...  
Keyword(s):  
Room Temperature ◽  
Raw Materials ◽  
Solidification Process ◽  
Curing Temperature ◽  
Alkali Concentration ◽  
Strength Development ◽  
Curing Time ◽  
Curing Conditions ◽  
Metakaolin Geopolymer ◽  
Geopolymer Paste

The properties of metakaolin geopolymer paste are affected by the alkali concentration, the initial raw materials, solidification process, and amount of mixing water as well as the curing conditions. This study aimed to investigate the effect of curing temperature (room temperature, 40°C, 60°C, 80°C and 100°C) and curing time (6h, 12h, 24h, 48h and 72h) on the geopolymer pastes produced from geopolymer powder. The results showed that curing at room temperature was unfeasible. Heat was required for the geopolymerization process, where strength increased as the curing temperature was increased. Moderate elevated curing temperature favored the strength development of geopolymer pastes in comparison with those treated with extreme elevated curing temperature. When geopolymer paste was subjected to extreme elevated curing temperature, shorter curing time should be used to avoid deterioration in strength gain. Similarly, longer curing time was recommended for moderate elevated curing temperature. The microstructure of geopolymer paste cured at moderate curing temperature showed obvious densification of structure. In contrast, the structure formed was weak and less compact at very high elevated curing temperature.

scholarly journals The Potential of Ladle Slag and Electric Arc Furnace Slag use in Synthesizing Alkali Activated Materials; the Influence of Curing on Mechanical Properties

Materials ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1173 ◽  
Author(s):  
Češnovar ◽  
Traven ◽  
Horvat ◽  
Ducman
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Room Temperature ◽  
Electric Arc Furnace ◽  
Electric Arc ◽  
Alkali Activation ◽  
Arc Furnace ◽  
Curing Time ◽  
Promising Alternative ◽  
Alkali Activated

Alkali activation is studied as a potential technology to produce a group of high performance building materials from industrial residues such as metallurgical slag. Namely, slags containing aluminate and silicate form a useful solid material when activated by an alkaline solution. The alkali-activated (AA) slag-based materials are promising alternative products for civil engineering sector and industrial purposes. In the present study the locally available electric arc furnace steel slag (Slag A) and the ladle furnace basic slag (Slag R) from different metallurgical industries in Slovenia were selected for alkali activation because of promising amorphous Al/Si rich content. Different mixtures of selected precursors were prepared in the Slag A/Slag R ratios 1/0, 3/1, 1/1, 1/3 and 0/1 and further activated with potassium silicate using an activator to slag ratio of 1:2 in order to select the optimal composition with respect to their mechanical properties. Bending strength of investigated samples ranged between 4 and 18 MPa, whereas compressive strength varied between 30 and 60 MPa. The optimal mixture (Slag A/Slag R = 1/1) was further used to study strength development under the influence of different curing temperatures at room temperature (R. T.), and in a heat-chamber at 50, 70 and 90 °C, and the effects of curing time for 1, 3, 7 and 28 days was furthermore studied. The influence of curing time at room temperature on the mechanical strength at an early age was found to be nearly linear. Further, it was shown that specimens cured at 70 °C for 3 days attained almost identical (bending/compressive) strength to those cured at room temperature for 28 days. Additionally, microstructure evaluation of input materials and samples cured under different conditions was performed by means of XRD, FTIR, SEM and mercury intrusion porosimetry (MIP).

Effect of Curing Conditions on the Mechanical Properties of Fly Ash-Based Geopolymer without Sodium Silicate Solution

2014 ◽  
Vol 699 ◽  
pp. 15-19 ◽  
Author(s):  
Rosniza Hanim Abdul Rahim ◽  
Khairun Azizi Azizli ◽  
Zakaria Man ◽  
Muhd Fadhil Nuruddin
Keyword(s):  
Compressive Strength ◽  
Elevated Temperature ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Room Temperature ◽  
Sodium Silicate Solution ◽  
Silicate Solution ◽  
Curing Temperature ◽  
Curing Time

Geopolymer is associated with the alkali activation of materials rich in Si and Al, and alkali activator such as sodium hydroxide is used for the dissolution of raw material with the addition of sodium silicate solution to increase the dissolution process. However, the trend of strength development of geopolymer using sodium hydroxide alone is not well established. This paper presents an evaluation on compressive strength of fly ash–based geopolymer by varying curing time with respect to different curing temperature using sodium hydroxide as the only activator. The samples were cured at room temperature and at an elevated temperature (60°C). Further analysis on the microstructure of geopolymer products cured at 60°C was carried out using Field Emission Scanning Microscopy (FESEM). It can be observed that the compressive strength increased as the curing time increased when cured at room temperature; whereas at elevated temperature, the strength increased up to a maximum 65.28 MPa at 14 days but gradually decreased at longer curing time. Better compressive strength can be obtained when the geopolymer was cured at an elevated temperature compared to curing at room temperature.

Morphology-Controlled Synthesis of 1D ZnO Nanostructures by Hydrothermal Technique

2011 ◽  
Vol 266 ◽  
pp. 17-21
Author(s):  
Zhi Duan Cai ◽  
Lin Dong ◽  
Guo Xi Cao ◽  
Xing Yan Zhang ◽  
Shao Kang Guan
Keyword(s):  
Room Temperature ◽  
Controlled Synthesis ◽  
Curing Process ◽  
Zno Nanostructures ◽  
Curing Time ◽  
Photoluminescence Spectra ◽  
Structural And Optical Properties ◽  
Hydrothermal Technique ◽  
Room Temperature Photoluminescence

A two-step hydrothermal synthesis technique has been developed to obtained 1D ZnO nanostructures with adjustable aspect ratio and size distribution. The pre-curing process has important influence on the morphological, structural and optical properties. The LO phonons of the nanowires obtained by pre-curing for 24 h exhibit slight batho-shift in comparison with nanorods. The increase of the intensity ratio of ultraviolet to visible emissions in room-temperature photoluminescence spectra show the improvement in the quality of ZnO nanostructures as the pre-curing time prolonged. The fitting result of EX energy at T=0 is 3.382 and 3.370 eV for ZnO nanowires and nanorods, respectively.

Study on Microwave Curing Behavior and Performance of Epoxy/Versamid 125

2012 ◽  
Vol 430-432 ◽  
pp. 281-284 ◽  
Author(s):  
Yun Bo Lei ◽  
Xue Juan Cao
Keyword(s):  
Room Temperature ◽  
Bending Strength ◽  
Good Condition ◽  
Curing Time ◽  
Epoxy System ◽  
Microwave Technology ◽  
Microwave Curing ◽  
And Performance ◽  
The Impact ◽  
Impact Ductility

The curing rate of epoxy/Versamid 125 (V125) by heating curing, room-temperature curing and microwave curing was compared. It is founded that applying microwave technology could effectively improve the curing rate and the curing time is only 3-4minutes. 140W microwave could cure the epoxy system in good condition, but 280W and 420W were easy to make the materials coking. The impact of diluent on mechnical properties of curing product were studied and it is showed that the impact strength increases and the impact ductility will be improved with the content of diluent increases, while the compressing strength, bending strength and tensile strength decrease.

scholarly journals Simulation and Experimental Verification of the Thermal Behaviour of Self-Written Waveguides

2021 ◽  
Vol 11 (17) ◽  
pp. 7881
Author(s):  
Axel Günther ◽  
Murat Baran ◽  
Wolfgang Kowalsky ◽  
Bernhard Roth
Keyword(s):  
Room Temperature ◽  
Optical Transmission ◽  
Numerical Aperture ◽  
Heating Process ◽  
Experimental Setup ◽  
Experimental Measurements ◽  
Curing Time ◽  
Material Parameters ◽  
Time Changes ◽  
Increasing Temperature

In this work, we investigated the optical response of a self-written waveguide (SWW) in detail by heating the structure from room temperature up to 60 °C. Previous results indicated a decrease in the optical transmission with increasing temperature for certain waveguide parameters. Based on new experimental measurements, we have identified material parameters resulting in opposite behaviour. An experimental setup was conceived to verify these results. Hereby, we were able to show that we can adjust material parameters such as refractive index and the corresponding density of the material by adapting the curing time applied during the fabrication of the waveguides. This, in turn, affects the material’s response during the heating process. We showed that a limitation of the external curing time changes the internal conditions of the SWW and the cladding in a manner that the numerical aperture increases with the temperature, which subsequently also results in an increase in the optical transmission. In this study, we explain this unexpected behavior of the SWW and point towards possible future applications.

Study on Extracting Vanadium from Coal Vanadium Ore

2011 ◽  
Vol 396-398 ◽  
pp. 504-507
Author(s):  
Cheng Xi
Keyword(s):  
Sulphuric Acid ◽  
Room Temperature ◽  
Tap Water ◽  
Size Fraction ◽  
Curing Temperature ◽  
Curing Time ◽  
Test Results ◽  
Leaching Rate ◽  
Solid Ratio ◽  
Sulphuric Acid Concentration

Coal vanadium ore from Hunan was pretreated by sulfuric acid for curing. Influences of curing time, curing temperature, sulphuric acid concentration and ore size fraction on vanadium leaching rate were investigated and discussed. Test results showed that: -100 mesh ore size was cured by 20% added quantity of sulphuric acid at 180°C for 24h and was leached by agitation with tap water, the liquid solid ratio of 4: 1 at room temperature for 12h, vanadium leaching rate was 74%

scholarly journals Durability and Strength Characteristics of Casein-Cemented Sand with Slag

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3182
Author(s):  
Sung-Sik Park ◽  
Seung-Wook Woo ◽  
Sueng-Won Jeong ◽  
Dong-Eun Lee
Keyword(s):  
Room Temperature ◽  
Water Resistance ◽  
Piezoelectric Sensor ◽  
Wood Adhesive ◽  
Curing Time ◽  
Unconfined Compression ◽  
Cemented Sand ◽  
Improve Water Resistance ◽  
Strength And Durability ◽  
Furnace Slag

Casein is often used as an eco-friendly wood adhesive. In this study, we used casein for soil cementation by mixing it with Jumunjin sand, sodium hydroxide (SH), and calcium hydroxide (CH) as a standard casein formula. The modified casein binder with different proportions of SH and CH was applied to improve water resistance. Furthermore, a blast furnace slag (BFS) was additionally mixed and reacted with alkalinity of modified casein binder. Thus, three types (standard, modified, and modified + BFS, referred to as STD, MOD, and MBS, hereafter) of casein binders were tested for durability and strength of casein-cemented sand. A piezoelectric sensor was installed within each sample to determine the curing time of the casein-cemented samples. The samples were air-cured at room temperature for seven days and some were repeatedly immersed in water thrice. Unconfined compression and jar slake tests were carried out to evaluate the strength and durability of the casein-cemented sand. Also, the microstructure was analyzed using a scanning electron microscope (SEM). We observed variations of peak conductance and corresponding frequency converged as the curing time increased. It was most significant for the MBS samples, which developed strength early. The unconfined compressive strength (UCS) of the air-cured samples was higher than those repeatedly immersed in water due to wash-off of the casein binder. The UCS of the dry MBS sample was 9900 kPa while that of the immersed sample was 430 kPa, which gradually decreased to 60 kPa upon repeated immersion. The samples with STD and MOD had no resistance to durability and showed cracks on the surface, while the MBS sample exhibited significantly improved durability and no cracks. We found that the MBS binder had a positively significant effect on the durability and strength of casein-cemented sand.

Fabrication of Diamond-Like Carbon Emitter Patterns by Room-Temperature Curing Nanoimprint Lithography with PDMS Molds Using Polysiloxane

MRS Advances ◽  
2016 ◽  
Vol 1 (16) ◽  
pp. 1075-1080 ◽  
Author(s):  
Shuji Kiyohara ◽  
Shogo Yoshida ◽  
Ippei Ishikawa ◽  
Toru Harigai ◽  
Hirofumi Takikawa ◽  
...  
Keyword(s):  
Nanoimprint Lithography ◽  
Room Temperature ◽  
Electron Cyclotron Resonance ◽  
Mold Material ◽  
Etching Time ◽  
Diamond Like Carbon ◽  
Curing Time ◽  
Flat Panel Display ◽  
Ion Energy ◽  
Mask Material

ABSTRACTWe investigated the fabrication of diamond-like carbon (DLC) emitter patterns by room-temperature curing nanoimprint lithography (RTC-NIL) with polydimethylsiloxane (PDMS) molds using polysiloxane, as an application to the emitter for the next generation flat panel display.The DLC which has excellent properties similar to diamond properties was used as a pattern material. A PDMS was used as a mold material and fabricated by the following optimum conditions of the first curing time at RT for 36 h and the second curing time at the temperature of 150 °C for 15 mins. The polysiloxane is in the state of sticky liquid at RT and stable in air. Therefore, the polysiloxane was used the electron beam (EB) resist and oxide mask material in EB lithography, and also used as RT-imprint material.First, we fabricated the PDMS mold with pit array. Each dot is 5 µm-diameter and 400 nm-depth. We carried out the RTC-NIL process with PDMS molds using polysiloxane under the following optimum imprint conditions of 0.5 MPa-imprinting pressure, 1.5 min-the time between spin-coat and imprint, and 5 min-imprinting time. Next, the residual layer of imprinted polysiloxane pattern was 450 nm and then was removed with electron cyclotron resonance (ECR) trifluoromethane (CHF3) ion shower under the conditions of 300 eV-ion energy and 3 min-etching time. Then, we processed the imprinted polysiloxane patterns on the DLC film with an ECR oxygen (O2) ion shower under the conditions of 400 eV-ion energy and 12 min-etching time. As a result, we succeeded in fabricating convex DLC emitter patterns with high accuracy which has 5 µm-diameter and 500 nm-height.

scholarly journals Variations in geotechnical characteristics of some crude oil contaminated soils

2020 ◽  
Vol 18 ◽  
pp. 75-88
Author(s):  
Ibrahim Adewuyi Oyediran ◽  
Nchewi Ideba Enya
Keyword(s):  
Hydraulic Conductivity ◽  
Crude Oil ◽  
Contaminated Soils ◽  
Room Temperature ◽  
Oil Content ◽  
Dry Density ◽  
Curing Time ◽  
Maximum Dry Density ◽  
Geotechnical Characteristics ◽  
Oil Concentration

Variations based on the effects of curing time and environmental exposures on the geotechnical characteristics of some crude oil contaminated soils were investigated. 2 to 10% by weight of crude oil was added to soils as a simulation of contamination. The contaminated soils were cured under room temperature (unexposed) as well as outside in the open air (exposed) for 21, 63 and 189 days. Geotechnical, geochemical and  mineralogical analyses were carried out on the contaminated and uncontaminated soil samples. Results indicate that for the unexposed soils, the LL and PL increased as crude oil concentration (COC) increased up to 4%, above which both decrease. But the reverse was the case for PI after curing for 21 days. With increasing curing time to 63 and 189 days, LL and PL both increased with increase in COC while PI decreased. The UCS increased with increase in oil content up to 4%, but decreased as oil content increased above 4%. Furthermore, UCS decreased with increase in curing time. Across all curing periods, MDD increased upon addition of crude oil up to 4%, thereafter it decreased with increase in COC. The hydraulic conductivity decreased with increase in COC and curing time. For the exposed soils, LL, PL and PI all increased upon addition of crude oil up till 4% before decreasing as the amount of oil increased above 4% for the curing duration of 21 days. For 63 and 189 days, LL and PL decreased while PI increased. Maximum dry density (MDD) showed same variation trend in exposed soils similar to that shown by the unexposed soils. Hydraulic conductivity increased with increase in COC and curing time. Thus, crude oil is observed to be capable of altering the geotechnical properties of soils exposed to it. Furthermore, contaminated soils exposed to the open air and longer curing time were significantly modified than the unexposed variant and with reduced exposure time. Keywords: Geotechnical variation, Contamination, Curing environment, Curing time, Exposure

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