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1.
Aesthetic Plast Surg ; 2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38691174

RESUMO

BACKGROUND: Transposition flaps are commonly used for facial-defect repair after wide excision of skin cancers. However, such repair often causes excessive tension at the donor site that can result in distortion of the adjacent area. The hatchet flap, a rotation-advancement flap, can prevent distortion by redistributing the donor site tension evenly to the recipient site. This study aims to compare the esthetic outcomes of the hatchet flap and transposition flap in facial-defect reconstruction. METHODS: We retrospectively included 50 patients who underwent facial reconstruction with the hatchet flap or transposition flap after excision of skin cancer. They were followed up for more than 6 months. At the last follow-up visit, the esthetic outcome was evaluated by subjective and objective assessments using the patients and observer scar assessment scale and Manchester scar scale. RESULTS: Thirty patients and 20 patients underwent reconstruction using the hatchet flap and the transposition flap, respectively. The total score from the patient and observer scar assessment scale was significantly lower in the hatchet flap group compared with the transposition flap group (p = 0.009). The Manchester scar scale showed a total score of 7.67 ± 2.2 for the hatchet flap and 9.95 ± 1.99 for the transposition flap: in the color (p < 0.001), distortion (p < 0.001), and texture (p < 0.02) categories, the hatchet flap yielded significantly better outcomes than the transposition flap. CONCLUSIONS: The hatchet flap had good esthetic outcome for facial reconstruction and could be a valuable option for reconstructing facial defects. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to Table of Contents or online Instructions to Authors www.springer.com/00266.

2.
Materials (Basel) ; 17(9)2024 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-38730923

RESUMO

This study investigated how process parameters of laser cladding affect the microstructure and mechanical properties of WC-12Co composite coating for use as a protective layer of continuous caster rolls. WC-Co powders, WC-Ni powders, and Ni-Cr alloy powder with various wear resistance characteristics were evaluated in order to determine their applicability for use as cladding materials for continuous caster roll coating. The cladding process was conducted with various parameters, including laser powers, cladding speeds, and powder feeding rates, then the phases, microstructure, and micro-hardness of the cladding layer were analyzed in each specimen. Results indicate that, to increase the hardness of the cladding layer in WC-Co composite coating, the dilution of the cladding layer by dissolution of Fe from the substrate should be minimized, and the formation of the Fe-Co alloy phase should be prevented. The mechanical properties and wear resistance of each powder with the same process parameters were compared and analyzed. The microstructure and mechanical properties of the laser cladding layer depend not only on the process parameters, but also on the powder characteristics, such as WC particle size and the type of binder material. Additionally, depending on the degree of thermal decomposition of WC particles and evolution of W distribution within the cladding layer, the hardness of each powder can differ significantly, and the wear mechanism can change.

3.
Materials (Basel) ; 17(6)2024 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-38541560

RESUMO

Herein, we conducted a comprehensive statistical assessment of the ultrasonic pulse velocity (UPV) method's effectiveness in predicting concrete strength under diverse conditions, specifically early age, middle age, and high-temperature exposure. The concrete mixtures, with water-to-cement (W/C) ratios of 0.33 and 0.28, were classified as granite aggregate or coal-ash aggregate mixes. Compressive strength and UPV measurements were performed under these conditions, and subsequent statistical analyses treated the identified factors as distinct groups. The results revealed a substantial difference in compressive strength between specimens at early age (average of 13.01) and those at middle age (average of 41.96) and after high-temperature exposure (average of 48.08). Conversely, UPV analysis showed an insignificant difference between the early-age specimens and those after high-temperature exposure. The analysis of the W/C ratio and coarse aggregate demonstrated significant differences (p-value < 0.05) in compressive strength between specimens in middle age and those exposed to high temperatures, excluding the early-age specimens. However, UPV analysis revealed insignificant differences, with p-values of 0.67 and 0.38 between specimens at an early age and post-high-temperature exposure, respectively. Regression analysis identified suitable functions for each scenario, emphasizing the importance of a strength prediction model for concrete after high-temperature exposure, particularly considering the W/C ratio. Since concrete showed statistically different compressive strength, UPV, and strength prediction models in three conditions (early age, middle age, and high temperature), different strength prediction models must be used for the purpose of accurately predicting the strength of concrete.

4.
Aesthetic Plast Surg ; 48(8): 1537-1546, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38334788

RESUMO

BACKGROUND: We hypothesized that application of acellular dermal matrix (ADM) over the orbital septum overlying the herniated orbital fat to tighten and strengthen the attenuated orbital septum in lower blepharoplasty would allow successful repositioning of the herniated orbital fat within the bony orbit. METHODS: The author prospectively compared the cosmetic outcomes of lower blepharoplasty using ADM with standard blepharoplasty. We evaluated recurrence of eyelid bulging and tear trough deformity, volume of the lower periorbital region, and enophthalmos and eyelid droop 1 year after surgery. RESULTS: Twenty-two of the 24 enrolled patients completed the study. There was no significant difference in recurrence of eyelid bulging and tear trough deformity between standard blepharoplasty and blepharoplasty with ADM graft groups. In the standard blepharoplasty group, the volume of the lower periorbital region decreased significantly after surgery. In the blepharoplasty with ADM graft group, there was no significant change in the volume of the lower periorbital region after surgery. In the standard blepharoplasty group, there was no significant change in eyelid droop on either side after surgery. In the blepharoplasty with ADM graft group, the eyelid droop decreased significantly after surgery on the right side but showed no significant change on the left side. There was no significant change in enophthalmos after surgery for either group. CONCLUSIONS: This study demonstrated that ADM graft provided effective support for maintaining the replaced orbital fat in lower blepharoplasty. In the long-term, blepharoplasty with ADM graft might be effective in slowing development of age-related enophthalmos. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .


Assuntos
Derme Acelular , Tecido Adiposo , Blefaroplastia , Órbita , Humanos , Blefaroplastia/métodos , Feminino , Pessoa de Meia-Idade , Tecido Adiposo/transplante , Masculino , Estudos Prospectivos , Órbita/cirurgia , Adulto , Idoso , Resultado do Tratamento
5.
Materials (Basel) ; 16(21)2023 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-37959447

RESUMO

Currently, in order to reduce the greenhouse gases of global warming, research on alternative cement materials is being actively conducted in the construction industry to reduce cement use, and it is judged to be important to evaluate the timing of form removal for the initial age. Therefore, in this study, we evaluated the initial mechanical properties of concrete in which cement was partially replaced with non-sintered hwangto (NHT). Specimens without NHT (namely, normal mortar (NM) and normal concrete (NC)) and specimens with NHT (namely, non-sintered hwangto mortar (HTM) and non-sintered hwangto concrete (HTC)) were prepared. NHT was substituted for 15% and 30% of cement. Two water-to-binder (W/B) ratios, 41% and 33%, were used to analyze the variation in the mechanical properties according to the cement and NHT content per unit volume of concrete. The compressive strength and ultrasonic pulse velocity (UPV) were measured. Experimental results indicated that compressive strength decreased with an increase in NHT content. The mortar with NHT substitution rates of 15% and 30% exhibited higher UPV than NM at a W/B ratio of 41%, in contrast to the behavior observed for concrete. The UPVs of most specimens were similar regardless of the NHT substitution rate. The correlation between the compressive strength and UPV of HTC was analyzed, and therefrom, exponential equations with a high correlation coefficient (R2) were proposed for strength prediction; the resulting predictions were compared with the results of previous compressive strength prediction models.

6.
Materials (Basel) ; 16(20)2023 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-37895781

RESUMO

The ultrasonic pulse velocity (UPV) technique, which is an efficient technique for concrete quality evaluation, can be affected by several factors. Many studies have proposed compressive-strength prediction models based on UPV in concrete; however, few studies have investigated the factors resulting in statistically different UPV results for different models. This study examined the difference between compressive strengths of various concrete specimens calculated by age-dependent and temperature-dependent UPV-based prediction models. Furthermore, a statistical analysis was conducted to evaluate the influence of aggregates and water/cement ratio (design compressive strength), which are said to affect UPV, on the compressive-strength prediction models. The experimental results revealed that the residual compressive strength of concrete after high-temperature exposure was about 9.5 to 24.8% higher than the age-dependent compressive strength. By contrast, after high-temperature exposure, UPV tended to be about 34.5% lower. The compressive strengths and UPVs were significantly different with respect to high temperature, aggregate density, and design compressive strength. The compressive-strength prediction model derived from the regression analysis showed a high R2 (average 0.91) and mean error converged to zero compared to the compressive-strength prediction model without considering these factors. Finally, the differences between the age- and temperature-based compressive-strength prediction models were analyzed according to the corresponding microstructures.

7.
Materials (Basel) ; 16(3)2023 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-36770109

RESUMO

Research on alternative cement materials is active worldwide, and in terms of fire safety, research on the evaluation of high-temperature properties of alternative materials is very important. Studies on concrete mixed with hwangto have been conducted by several researchers, but studies on high-temperature properties are lacking. Therefore, in this study, we evaluated the mechanical properties of concrete by partially replacing cement with non-sintered hwangto (NSH) at high temperatures. Normal concrete without NSH mixing and non-sintered hwangto concrete (NSHC) with HNT replacement were prepared as the specimens. The W/B of the concrete was set to 41 and 33, whereas the NSH replacement ratio was 15 and 30% of the cement. The target heating temperatures were set to 20, 100, 200, 300, 500, and 700 °C, and the heating rate was maintained at 1 °C/min. The following were calculated to evaluate the mechanical properties of the specimens: mass loss, compressive strength, ultrasonic pulse velocity (UPV), and modulus of elasticity. After analyzing the correlation between residual compressive strength and UPV, we proposed a compressive strength prediction model using different values of W/B for NSHC. Experimental results suggest that mass loss (%) shows a decreasing trend as NSH increases. In terms of residual compressive strength, residual compressive strength at W/B 41 increased with NSH replacement, whereas residual compressive strength values for W/B 33 were observed regardless of NSH replacement. Residual UPV showed a similar trend, regardless of the NSH replacement ratio, and residual modulus of elasticity was low at all W/B ratios as NSH replacement increased. A linear equation with a high correlation coefficient (R2) was proposed to predict compressive strength, and the linear value of W/B 41 was slightly higher than that of W/B 33.

8.
Materials (Basel) ; 16(2)2023 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-36676252

RESUMO

This study measured and analyzed the mechanical properties of normal aggregate concrete (NC) and lightweight aggregate concrete (LC) subjected to high temperatures. The target temperature was set to 100, 200, 300, 500, and 700 °C, and W/C was set to 0.41, 0.33 and 0.28 to evaluate high temperature properties at various intensities. Measurement parameters included mass loss, compressive strength, ultrasonic pulse velocity (UPV), and elastic modulus. We compared the residual mechanical properties between the target and preheating temperatures (20 °C) and then analyzed the correlation between UPV and compressive strength. According to the research findings, after exposure to high temperatures, LC demonstrated a higher mass reduction rate than NC at all levels and exhibited higher residual mechanical properties. The results of analyzing the correlation between compressive strength and UPV for concrete subjected high temperatures were very different from the compressive strength prediction equation previous proposed at room temperature, and the error range of the residual strength prediction equation considering W/C was reduced.

9.
Chemosphere ; 315: 137789, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36626953

RESUMO

A hydrometallurgy is one of the most important techniques for recycling waste LIBs, where identifying the exact composition of the metal-leached solution is critical in controlling the metal extraction efficiency and the stoichiometry of the regenerated product. In this study, we report a simple and selective optical detection of high-concentrated Co2+ using a graphitic carbon nitride (g-CN)-based fluorescent chemosensor. g-CN is prepared by molten salt synthesis using dicyandiamide (DCDA) and LiI/KI. The mass ratio of LiI/KI to DCDA modifies the resulting g-CN (CNI) in terms of in-plane molecular distances of base sites including cyano functional groups (─CN) and fluorescent emission wavelength via nucleophilic substitution. The fluorescent sensing performance of CNIs is evaluated through photoluminescence (PL) emission spectroscopy in a broad Co2+ concentration range (10-4-100 M). The correlation between the surface exposure of hidden nitrogen pots (base sites) and PL intensity change is achieved where the linear relationship between the PL quenching and the logarithm of Co2+ concentration in the analyte solution is well established with the regression of 0.9959. This study will provide the design principle of the chemosensor suitable for the fast and accurate optical detection of Co2+ present in a broad concentration range for hydrometallurgy for the recycling of waste LIBs.


Assuntos
Grafite , Lítio , Cobalto/química , Metais , Íons , Fontes de Energia Elétrica , Reciclagem/métodos , Corantes
10.
Materials (Basel) ; 17(1)2023 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-38204026

RESUMO

This paper presents and investigates the properties of concrete in which a portion of the cement is substituted with non-sintered Hwangto (NSH), a readily available building material in Asia. Given the inactive nature of NSH, this study aimed to determine the optimal cement replacement ratio and quantitative strength of the material. The unit weight, compressive strength, ultrasonic pulse velocity (UPV), and stress-strain of the NSH concrete (NSHC) were evaluated. Additionally, we developed a predictive model for determining compressive strength based on the regression analysis of compressive strength and UPV. The water-to-binder ratio was set to 0.41, 0.33, and 0.28, and the NSH replacement rates in the cement were set to 0%, 15%, 30%, and 45% for evaluating various strength ranges. The mechanical property measurements indicated reductions of 5.35% in unit weight, 35.62% in compressive strength, and 6.34% in UPV as the NSH was replaced. Notably, the smallest deviation from plain concrete was observed at a replacement rate of 15%. The scanning electron microscopy analysis results showed that the plain concrete exhibited a crystalloid structure; however, as the NSH replacement rate increased, the amorphous structure and pores increased while unreacted NSH particles were also observed. The X-ray diffraction analysis results demonstrate that the peak intensities for kaolinite and mullite increased as the NSH replacement rate increased, while those of C-S-H gel and CaO showed low peak intensities. Furthermore, the regression analysis concluded that an exponential function was suitable. Consequently, a compressive strength prediction model was developed, and in the error test, the NSHC model demonstrated an average error of <10%, with fewer errors at the lower compressive strength boundaries.

11.
Materials (Basel) ; 15(8)2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35454644

RESUMO

This study classified the strength of normal aggregate concrete (NC) and lightweight aggregate concrete (LC) into three levels (30, 45, and 60 MPa). In particular, the compressive strength, ultrasonic pulse velocity, and elastic modulus were measured and analyzed at the ages of 1, 3, 7, and 28 days to establish the correlation between the compressive strength and the ultrasonic pulse velocity and between the elastic modulus and the ultrasonic pulse velocity. In addition, this study proposed strength and elastic modulus prediction equations as functions of the ultrasonic pulse velocity. The developed equations were compared with previously proposed strength prediction equations. The results showed that the measured mechanical properties of NC tended to be higher at all ages than in LC. However, LC45 exhibited relatively high compressive strength compared to NC45. The relative mechanical properties of LC compared to NC were the highest at 45 MPa and the lowest at 60 MPa. The relative ultrasonic pulse velocity converged at all levels as the age increased. Moreover, the correlation between the compressive strength and the ultrasonic pulse velocity in LC exceeded that of NC, and in LC, the correlation coefficient decreased as the strength increased. The correlation coefficients between the elastic modulus and the ultrasonic pulse velocity were high at all levels except for LC45. Finally, this study proposed compressive strength and elastic modulus prediction equations as an exponential function of LC. The proposed equations outperformed the previously proposed strength prediction equations.

12.
Materials (Basel) ; 15(7)2022 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-35407827

RESUMO

In this study, the effect of fine blast furnace slag powder (SP) and limestone powder (LSP) as a mineral admixture in shotcrete using monocalcium aluminate (CA) as a quick-setting accelerator was evaluated. The shotcrete was prepared with up to 25 wt.% substitutions of mineral admixture, i.e., (SP and LSP), and then the CA accelerator was incorporated by 5 wt.% of binders. To examine the optimal mixing ratio for mineral admixture in shotcrete, penetration resistance, compressive strength, XRD analysis, and MIP analysis were performed on the mortar. On the other hand, compressive strength test, chloride diffusion coefficient, and freeze-thaw resistance were conducted on concrete to evaluate the field applicability of shotcrete. The study revealed the addition of LSP improved setting time and early compressive strength while the addition of SP increased long-term compressive strength. With the addition of both SP and LSP, the early and long-term strength was increased due to the influence of the properties of each admixture. Furthermore, the addition of SP and LSP improves the resistance of shotcrete to chloride ions and freeze-thaw.

13.
Materials (Basel) ; 14(20)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34683685

RESUMO

The effect of the thermal properties of aggregates on the mechanical properties of high-strength concrete was evaluated under loading and high-temperature conditions. For the concrete, granite was selected as a natural aggregate, and ash-clay and clay as lightweight aggregates. The mechanical properties of the concrete (stress-strain, compressive strength, elastic modulus, thermal strain, and transient creep) were evaluated experimentally under uniform heating from 20 to 700 °C while maintaining the load at 0, 20, and 40% of the compressive strength at room temperature. Experimental results showed that the concrete containing lightweight aggregates had better mechanical properties, such as compressive strength and elastic modulus, than that of the concrete with a granite aggregate at high temperature. In particular, the concrete containing lightweight aggregates exhibited high compressive strength (60-80% of that at room temperature) even at 700 °C. Moreover, the concrete containing granite exhibited a higher thermal strain than that containing lightweight aggregates. The influence of the binding force under loaded conditions, however, was found to be larger for the latter type. The transient creep caused by the loading was constant regardless of the aggregate type below 500 °C but increased more rapidly when the coefficient of the thermal expansion of the aggregate was above 500 °C.

14.
Materials (Basel) ; 14(17)2021 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-34500992

RESUMO

This study sought to examine the performance design of concrete mix proportions to ensure chloride resistance and early strength with respect to C35 (35 MPa), which is the minimum compressive strength class of concrete used in a marine environment. For the proposed concrete mixture, C24 (24 MPa) was selected and binders for concrete were manufactured using a blend of OPC (ordinary Portland cement), EPC (early Portland cement), and GGBS (ground granulated blast-furnace slag). The results of the experiment confirmed that the combined use of EPC and GGBS greatly improve the early-strength development and chloride resistance of concrete. An analysis revealed that the time for removal of forms can be reduced by 5-9 h from the aspect of early concrete strength. Moreover, in terms of construction productivity, EPC and GGBS were reduced by up to 16.39 h/cycle compared to other concretes. Regarding economic and environmental impacts, EPC and GGBS were more effective than C35 concrete. This study is significant as its findings help make it possible to examine the most economical concrete mix design in relation to strength development according to the application of EPC, GGBS, and PC-based admixtures.

15.
Chemosphere ; 283: 131174, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34146886

RESUMO

Large particulate photocatalysts allow efficient recovery or installation into the substrate, while limiting possible light-catalyst interaction or mass/charge-transfer. In this study, we developed monodisperse organic single-crystal monoliths with controllable dimensions in the range of 10-100 µm. These were prepared on a 10-g scale by a solution-processed molecular cooperative assembly between melamine (M) and trithiocyanuric acid (TCA) and then transformed into the corresponding g-CN (MTCA-CN) by thermal polycondensation. Molecular precursors that are tightly bound in the crystal undergo polycondensation without losing their macroscopic properties depending on the dimensions of MTCA, thereby changing the microstructure, electronic structure, and photocatalytic activity. Such dimensional tunability enables the fulfillment of various catalytic requirements such as particle size, light absorption, charge separation, band edge potential, and mass transfer. As a proof-of-concept, it was shown that MTCA-CN is tailored to have a high rate of evolution of hydrogen (3.19 µmol/h) from glucose via photoreforming under AM1.5G by using MTCA-100 crystals, leading to the formation of g-CN with the more positive highest occupied molecular orbital (HOMO) level. This study highlights the possibility of developing photocatalysts for practical use and obtaining value-added products (VAPs) without losing the photocatalytic activity relevant for wastewater treatment.


Assuntos
Glucose , Luz Solar , Grafite , Hidrogênio , Nitrilas , Compostos de Nitrogênio
16.
Nanomaterials (Basel) ; 11(2)2021 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-33562661

RESUMO

The lithium-polysulfide (LiPS) dissolution from the cathode to the organic electrolyte is the main challenge for high-energy-density lithium-sulfur batteries (LSBs). Herein, we present a multi-functional porous carbon, melamine cyanurate (MCA)-glucose-derived carbon (MGC), with superior porosity, electrical conductivity, and polysulfide affinity as an efficient sulfur support to mitigate the shuttle effect. MGC is prepared via a reactive templating approach, wherein the organic MCA crystals are utilized as the pore-/micro-structure-directing agent and nitrogen source. The homogeneous coating of spherical MCA crystal particles with glucose followed by carbonization at 600 °C leads to the formation of hierarchical porous hollow carbon spheres with abundant pyridinic N-functional groups without losing their microstructural ordering. Moreover, MGC enables facile penetration and intensive anchoring of LiPS, especially under high loading sulfur conditions. Consequently, the MGC cathode exhibited a high areal capacity of 5.79 mAh cm-2 at 1 mA cm-2 and high loading sulfur of 6.0 mg cm-2 with a minor capacity decay rate of 0.18% per cycle for 100 cycles.

17.
Nanomaterials (Basel) ; 12(1)2021 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-35009960

RESUMO

To prevent global warming, ESS development is in progress along with the development of electric vehicles and renewable energy. However, the state-of-the-art technology, i.e., lithium-ion batteries, has reached its limitation, and thus the need for high-performance batteries with improved energy and power density is increasing. Lithium-sulfur batteries (LSBs) are attracting enormous attention because of their high theoretical energy density. However, there are technical barriers to its commercialization such as the formation of dendrites on the anode and the shuttle effect of the cathode. To resolve these issues, a boron nitride nanotube (BNNT)-based separator is developed. The BNNT is physically purified so that the purified BNNT (p-BNNT) has a homogeneous pore structure because of random stacking and partial charge on the surface due to the difference of electronegativity between B and N. Compared to the conventional polypropylene (PP) separator, the p-BNNT loaded PP separator prevents the dendrite formation on the Li metal anode, facilitates the ion transfer through the separator, and alleviates the shuttle effect at the cathode. With these effects, the p-BNNT loaded PP separators enable the LSB cells to achieve a specific capacity of 1429 mAh/g, and long-term stability over 200 cycles.

18.
Materials (Basel) ; 13(23)2020 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-33261202

RESUMO

This study analyzed the performance evaluation of alkali-activated composites (AAC) with an alkali-sulfate activator and determined the expected effects of applying AACs to actual sites. Results revealed that when the binder weight was increased by 100 kg/m3 at 7 days of age, the homogel strength of ordinary Portland cement (OPC) and AAC increased by 0.9 and 5.0 MPa, respectively. According to the analysis of the matrix microstructures at 7 days of age, calcium silicate hydrates (C-S-H, Ca1.5SiO3.5·H2O) and ettringite (Ca6Al2(SO4)3(OH)12·26H2O) were formed in AAC, which are similar hydration products as found in OPC. Furthermore, the acid resistance analysis showed that the mass change of AAC in HCl and H2SO4 solutions ranged from 36.1% to 88.0%, lower than that of OPC, indicating AAC's superior acid resistance. Moreover, the OPC and AAC binder weight ranges satisfying the target geltime (20-50 s) were estimated as 180.1-471.1 kg/m3 and 261.2-469.9 kg/m3, respectively, and the global warming potential (GWP) according to binder weight range was 102.3-257.3 kg CO2 eq/m3 and 72.9-126.0 kg CO2 eq/m3. Therefore, by applying AAC to actual sites, GWP is expected to be 29.5 (28.8%)-131.3 (51.0%) kg CO2 eq/m3 less than that of OPC.

19.
Materials (Basel) ; 13(20)2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-33081301

RESUMO

This study evaluated the use of electrolyzed alkaline-reduced water instead of an alkaline activator for the production of a strong cement matrix with a large blast furnace slag replacement ratio. The flexural and compressive strength measurements, X-ray diffraction analysis, and scanning electron microscopy images of the cement matrices produced using electrolyzed alkaline-reduced water and regular tap water, and with blast furnace slag replacement ratios of 30 and 50% were compared to a normal cement matrix. The cement matrix produced using electrolyzed alkaline-reduced water and blast furnace slag exhibited an improved early age strength, where hydrate formation increased on the particle surface. The cement matrix produced using electrolyzed alkaline-reduced water exhibited a high strength development rate of over 90% of ordinary Portland cement (OPC) in BFS30. Therefore, the use of electrolyzed alkaline-reduced water in the place of an alkaline activator allowed for the formation of a very strong cement matrix in the early stages of aging when a large blast furnace slag replacement ratio was used.

20.
Nanomaterials (Basel) ; 10(10)2020 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-33053839

RESUMO

Rechargeable lithium-sulfur batteries (LSBs) are emerging as some of the most promising next-generation battery alternatives to state-of-the-art lithium-ion batteries (LIBs) due to their high gravimetric energy density, being inexpensive, and having an abundance of elemental sulfur (S8). However, one main, well-known drawback of LSBs is the so-called polysulfide shuttling, where the polysulfide dissolves into organic electrolytes from sulfur host materials. Numerous studies have shown the ability of porous carbon as a sulfur host material. Porous carbon can significantly impede polysulfide shuttling and mitigate the insulating passivation layers, such as Li2S, owing to its intrinsic high electrical conductivity. This work suggests a scalable and straightforward one-step synthesis method to prepare a unique interconnected microporous and mesoporous carbon framework via salt templating with a eutectic mixture of LiI and KI at 800 °C in an inert atmosphere. The synthesis step used environmentally friendly water as a washing solvent to remove salt from the carbon-salt mixture. When employed as a sulfur host material, the electrode exhibited an excellent capacity of 780 mAh g-1 at 500 mA g-1 and a sulfur loading mass of 2 mg cm-2 with a minor capacity loss of 0.36% per cycle for 100 cycles. This synthesis method of a unique porous carbon structure could provide a new avenue for the development of an electrode with a high retention capacity and high accommodated sulfur for electrochemical energy storage applications.

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