Preparation Of Materials Research Articles

Development and preparation of novel nano-enhanced organic eutectic phase change materials for low-temperature solar thermal applications

ABSTRACT Thermally reliable and stable eco-friendly Phase change materials are of significant aid in thermal energy storage technology, leading to improved energy utilization and reliability of the system. This study develops two novel organic eutectic PCM of Lauric acid – Margaric acid (LM) and Myristic acid – Margaric acid (MM), which are chemically stable and thermally compatible for latent heat energy storage. LM eutectic mixture had a melting temperature of 52.66°C with a latent heat of 163.68 J/g, and MM eutectic mixture had its melting temperature at 44.79°C and a latent heat of 197.31 J/g. The phase change temperatures were favorable for low temperature solar thermal applications with good latent heat capacity. The thermal characteristics of these eutectic mixtures are further enhanced with the dispersion of highly conductive Multi walled carbon nanotubes (MWCNT) at three different mass fractions (.5%, 1% and 1.5% by weight). Nano enhancement could achieve exceptional thermal conductivity enhancement in MM eutectic mixture by 110.6% and 83.73% in LM eutectic mixture. Thermogravimetric analysis and Fourier-transform infrared spectroscopy analysis ensured the thermal and chemical stability of the eutectic mixtures. The optical absorption characteristics were extensively enhanced with nano particle addition, which is highly preferable in solar thermal applications.

MXene-modified lemon peel-based composite phase change material with excellent photo-thermal conversion efficiency, thermal storage capacity and thermal conductivity for thermal management of electronic components

The preparation of multifunctional composite phase change materials using green technology to achieve an efficient energy storage and conversion remains an issue of concern. In this paper, a lemon peel-based porous carbon (LPC) composite phase change material (CPCM) was prepared by using polyethylene glycol (PEG) 6000 as a phase change medium and MXene nanosheet-modified carbonized lemon peel as a support carrier. MXene nanosheets were bonded to a lemon peel-based porous carbon skeleton to construct an excellent continuous three-dimensional thermally conductive grid system. What makes it noteworthy is that the presence of MXene nanosheets substantially improves the thermal conductivity (0.66 W/mK) and photo-thermal conversion efficiency (θ = 96.4 %) of MXene-modified lemon peel-based porous carbon/polyethylene glycol composite phase change materials (PEG/LPC@M). It is noteworthy that PEG/LPC@M has remarkable thermal stability and still has high enthalpy after 100 cycles, which further proves the recyclability of PEG/LPC@M and PEG/LPC@M embodies great potential in the field of thermal management of electronic components. In conclusion, a novel multifunctional CPCM was prepared by a simple and green process method in this study, which provides a new idea for waste recycling and reuse, and also has a wide range of applications in thermal management of electronic devices.

Direct observation and characterization of a novel long period stacking ordered phase in GH4169 alloy

As is widely recognized, the Long Period Stacking Ordered (LPSO) phase is an important strengthening phase in the rare earth magnesium alloys. The LPSO phase not only enhances the strength of the alloy, but also improves its plasticity, thereby effectively addressing the strength-ductility trade-off phenomenon. Therefore, the preparation of metallic materials containing LPSO phase provides a new idea for designing a new generation of high-strength and high-toughness alloys. In present study, A novel nano-sized LPSO phase is observed and characterized for the first time in GH4169 nickel-based alloy. The results show that the stacking sequence of the LPSO phase is ABCBCBA, which indicates that this LPSO phase has a 6H structure. Meanwhile, the orientation relationships between LPSO phase and the Ni matrix are (11–1)γ//(0006)LPSO and [011]γ//[2-1-10]LPSO.

Nutritional Characteristics and Sensory Properties of Maize-based Ogi Supplemented with Mushroom (Pleurotus ostreatus) Flour

The study evaluates the effect of supplementation of maize-based ogi with mushroom (Pleurotus ostreatus) flour on nutritional characteristics and sensory properties. Standard processing and analytical methods were used in raw material preparation and analyses. Ogi and mushroom flour were blended in ratio of 100:0, 90:10, 80:20, 70:30 and labeled A, B, C and D respectively. A commercial maize based complementary food was used as control. There was significant difference (p < 0.05) among all samples for all the Vitamin assayed with values ranging from 4.86 to 9.06 (µg/100g), 0.32 to 1.09 mg/100 g, 0.22 to 0.69 mg/100 g, 3.82 to 13.03 mg/100 g and 0.13 to 1.12 mg/100 g for vitamin A, B1, B2, B3 and C. The vitamin values compare favourably with that of control sample. Significant (P<0.05) difference exists across the samples for Zn, Mg, Fe, K and Ca with values ranging from 1.12 to 1.71 mg/100 g, 37.7 to 102 mg/100 g, 4.72 to 13.23 mg/100 g, 23.05 to 125.3 mg/100 g and 125.5 to 160.25 mg/100 g respectively with corresponding higher values for control sample. Result showed negligible amounts of anti-nutritional factors ranging from 0.29 to 0.36 mg/100 g, 0.02 to 0.03 mg/100 g, 0.03 to 0.06 mg/100 g and 0.56 to 0.83 mg/100 g for phytate, oxalate, trypsin inhibitor and tannin respectively. The functional properties of the flour blends values ranged from 0.58 to 0.72 g/mL, 0.99 to 2.2 g/g, 5.21 to 8.94 g/g, 1.75 to 3.72 mL/g and 5.5 to 9.0% for bulk density, water absorption capacity, water retention capacity, swelling capacity and least gelation concentration respectively. Sensory scores revealed substantial overall acceptability of the samples. The quality of ogi samples were greatly improved by mushroom supplementation and could be nutritional beneficial to children and adults.

Synergistic effect of stearic acid/bismuth oxychloride/cupric oxide for thermal storage applications: preparation, stability, rheological and thermophysical analysis

Abstract The present study reports the preparation of nanophase change materials (NPCMs) using a two-step method with an optimized ratio of 0.5 wt.% of nanoparticles for thermal storage applications. Bismuth oxychloride (BiOCl), cupric oxide (CuO), and a mixture of BiOCl/CuO (composite) were used as nanoparticles, and stearic acid was used as the PCM. The crystallography, chemical/functional groups and morphologies of the prepared NPCMs have been analysed by XRD, FT-IR and SEM, respectively. Observations revealed that the presence of nanoparticles in NPCMs did not affect crystal formation or chemical disruption of molecular interactions. TGA was used to analyse the thermal stability and rate of deterioration of the NPCMs. The deterioration of the PCM occurs at 243℃ with a weight loss of 1.3% while 0.5 wt.% concentrated BiOCl, CuO, and composite NPCMs exhibit weight losses of 1.8%, 2.3%, and 3.4%, respectively at 257℃, 262℃ and 258℃. In the DSC study, the phase-changing attributes of the NPCMs manifested in the onset temperature range between 53.4°C and 59.8°C. The potential enthalpy of the PCM is 209.1 kJ/kg, whereas those of the 0.5 wt.% concentrated BiOCl, CuO, and composite NPCMs are 204.6, 198.3, and 201.7 kJ/kg, respectively. However, the enhanced thermal conductivities of 0.5 wt.% concentrated BiOCl, CuO, and the composite NPCMs are 0.18, 0.22, and 0.20 W/(m.℃), respectively, which are 5.9%, 29.4% and 17.6% greater than that of PCM. Additionally, the congruent melting rate increased by 31% for 0.5 wt.% CuO concentrated NPCM; therefore, it is a potential candidate than other NPCMs/PCM. Cyclic tests were conducted to assess the reliability of the NPCMs, and compatible results were obtained even after 500 cycles. The findings of this work indicate that all the prepared NPCMs could be a viable option for practical applications, including thermal comfort buildings, solar heating, and electronic cooling.

Eco-friendly, high-toughness gypsum prepared using hemihydrate phosphogypsum, fly ash, and glass fibers: Characterization and environmental impacts

Hemihydrate phosphogypsum (HPG), obtained as a cementitious material from the dewatering of phosphogypsum, can be widely used in the preparation of construction materials owing to its low cost and environmental friendliness. However, current reports on HPG mainly focus on hydration behavior, mechanical properties, and durability, and there are few studies focusing on the enhancement of HPG toughness. In this work, glass fibers (GF) and fly ash (FA), as composite reinforcement, were mixed with HPG during its preparation to obtain eco-friendly, high-toughness gypsum. The workability, mechanical, microstructural, financial and environmental properties of the HPG-based composites with different GF volume dosages (0, 0.5, 1.0, and 1.5 vol%) and FA weight percentages (0, 10, 20, and 30 wt%) were comparatively investigated. The results show that the addition of an appropriate amount of FA can improve the interface transition zone between GF and the matrix and effectively increase the flexural strength and toughness of the composites. For the optimal mixture containing 1.5 vol% GF and 20 wt% FA, the flexural strength and toughness were 50.7% and 82.2% higher, respectively, than those of the mixture without FA and 99.2% and 675.3% higher, respectively, than those of the control sample (without GF and FA). Cost-benefit and environmental impact analyses also indicated that this composite was the most economical and environmentally friendly. Thus, this work provides an effective approach to achieve the high-value utilization of two major industrial by-products.

Non-Verbal Communication Aspect in Paper Umbrella Craft as Intangible Cultural Heritage in Malang

Paper umbrellas are one of the crafts included in the intangible cultural heritage of Malang, East Java. Currently, it is known that there is only one group of craftsmen who still produce this paper umbrella craft. Although not many of them, this paper umbrella craft still exists among people who like traditional handicrafts. This is evident from how often paper umbrella crafts appear at craft exhibitions in cities in Indonesia. Consequently, there is a pressing need for in-depth research on paper umbrella craftsmanship in Malang City. A valuable avenue for exploration is the examination of non-verbal communication aspects inherent in paper umbrella craftsmanship. This study aimed to determine the non-verbal communication aspects contained in paper umbrella crafts. The research employs a descriptive qualitative approach, focusing on analyzing non-verbal communication aspects. Data was collected using unstructured interview methods, documentation, and field surveys. The collected data was reduced for analysis using nonverbal communication theory. The study findings are presented descriptively, detailing the observed non-verbal communication aspects. The findings reveal three distinct categories of non-verbal communication aspects in paper umbrella craftsmanship: fixed features, semi-fixed features, and non-fixed features. Fixed features include shapes depicted on the umbrella. Semi fixed feature is a choice of material used to make paper umbrellas, colors, and motifs. The materials used are bamboo and paper. The colors of the umbrellas are red and green. The motif drawn on the umbrella is a floral motif. Flowers are present because they are the favorite shapes of the craftsmen who make umbrellas. Non-fixed features encompass the entire process of crafting paper umbrellas, from material preparation to final finishing touches. Keywords: umbrella paper, craft, tangible cultural heritage

General strategy for developing thick-film micro-thermoelectric coolers from material fabrication to device integration

Micro-thermoelectric coolers are emerging as a promising solution for high-density cooling applications in confined spaces. Unlike thin-film micro-thermoelectric coolers with high cooling flux at the expense of cooling temperature difference due to very short thermoelectric legs, thick-film micro-thermoelectric coolers can achieve better comprehensive cooling performance. However, they still face significant challenges in both material preparation and device integration. Herein, we propose a design strategy which combines Bi2Te3-based thick film prepared by powder direct molding with micro-thermoelectric cooler integrated via phase-change batch transfer. Accurate thickness control and relatively high thermoelectric performance can be achieved for the thick film, and the high-density-integrated thick-film micro-thermoelectric cooler exhibits excellent performance with maximum cooling temperature difference of 40.6 K and maximum cooling flux of 56.5 W·cm−2 at room temperature. The micro-thermoelectric cooler also shows high temperature control accuracy (0.01 K) and reliability (over 30000 cooling cycles). Moreover, the device demonstrates remarkable capacity in power generation with normalized power density up to 214.0 μW · cm−2 · K−2. This study provides a general and scalable route for developing high-performance thick-film micro-thermoelectric cooler, benefiting widespread applications in thermal management of microsystems.

Efficient Ionic Conductor Anode Materials with Heterojunction Structure of MnOx/Si@C Utilized in Lithium‐Ion Batteries

AbstractThe rapid development of alternative energy vehicles has raised higher requirements for electrode materials. Silicon, with superhigh specific capacity, is highly anticipated in the field of lithium‐ion batteries (LIBs). Unfortunately, the original drawbacks of serious volumetric effect and poor conductivity have confined its commercial steps severely. Herein, a novel composite, based on submicron silicon flakes embedded into carbon shell, with heterojunction‐bearing MnOx nanoparticles, is designed and synthesized successfully via sanding process and in situ thermal reduction methods. The results of electrochemical performance tests and related fitting data show that the presence of MnOx particles facilitates rapid Li+ transport and reduces the impedance associated with Li+ diffusion from the surface to the inner core of the MnOx/Si@C material. The two‐dimensional (2D) silicon flakes and uniform carbon shell have positive influence on structural stability and electronic conductivity. Benefit from the rational design, the optimized MnOx/Si@C composite delivers an outstanding cycling stability of 1106.59 mAh·g−1 at 1 A·g−1 over 1000 cycles with a capacity retention of 71.09%. Besides, the goal material possesses a lithium‐ion diffusion coefficient of ≈1.04×10−9 cm2·s−1. This work provides a reference for the mass preparation of advanced anode materials for lithium‐ion batteries.

Preparation of a Consolidation Material of Organosilica-Modified Acrylate Emulsion for Earthen Sites and the Evaluation of Its Effectiveness

In this paper, a new consolidation material for earthen sites with silicone-modified acrylic emulsion was synthesized and applied to the consolidation test of soil samples of the site. The effectiveness was tested through the properties of soil samples on the changes in weight, color, permeability test, air permeability, hydrolysis resistance, water resistance, and salt resistance. The results show that the samples treated with the new material have an outstanding effect on hydrolysis resistance, water resistance, and salt resistance without the change in color and gas permeability. After being soaked in Na2SO4 and sodium chloride solution for half a month, the reinforced soil sample did not crack, and it could undergo 15 days of water resistance test and five cycles of sodium sulfate resistance.

Preparation and properties of a metal-organic frameworks polymer material based on Sa-son seed gum capable of simultaneously absorbing liquid water and water vapor

Atmospheric water harvesting (AWH) technology has attracted significant attention as an effective strategy to tackle the global shortage of freshwater resources. Work has focused on the use of hydrogel-based composite adsorbents in water harvesting and water conservation. The approaches adopted to make use of hygroscopic inorganic salts which subject to a “salting out” effect. In this study, we report the first use of modified UIO-66-NH2 as a functional steric cross-linker and Sa-son seed gum was used as polymeric substrate to construct super hygroscopic hydrogels by free radical copolymerization. The maximum water uptake on SMAGs (572 cm3·g−1) outperforms pure UIO-66-NH2 (317 cm3·g−1). Simultaneously, our first attempt to use it for anti-evaporation applications in an arid environment (Lanzhou, China) simulating sandy areas. The evaporation rate of the anti-evaporation material treated with 0.20 % super moisture-absorbent gels (SMAGs) decreased by 6.1 % over 64 h period under natural condition in Lanzhou, China. The prepared material can not only absorb liquid water but also water vapor, which can provide a new way for water collection and conservation technology. The design strategy of this material has wide applications ranging from atmospheric water harvesting materials to anti-evaporation technology.

A graphene-like hollow sphere anode for lithium-ion batteries.

We report a flash Joule heating method for the rapid preparation of graphene-like materials. The L-GHS exhibited a uniform diameter of 200 nm and an ideal specific surface area of 670 m2 g-1. Meanwhile, the specific capacity of L-GHS remained at 942 mA h g-1 after 600 cycles (1 A g-1), which shows excellent electrochemical performance.

The Functional Role of Disordered Metal Oxides from Active Catalysis to Biological Metabolism

AbstractIt has been observed by many authors that highly active electrocatalysts are frequently “disordered” or “amorphous” in nature. The correlation between this lack of order and functionality is highly debated, with researchers still questioning if this structural property is a simple coincidence of the material preparation method, or if this lack of order has an important functional role for these catalysts. Using metal oxides as an example, how amorphous and disordered metal oxides can react by fundamentally different pathways are explored from more ordered forms with very similar bonding and redox states. The distinction between amorphous, disordered, and crystalline materials is reviewed in different characterization methods and suggests how these material characteristics fundamentally change the reactivity of these materials beyond surface area effects. How disorder can change the underlying thermodynamic stability of a material is explored, which in turn impacts redox potential, proton‐transfer, and electron‐transfer properties. It is these fundamental properties that govern the electrocatalytic activity and microbial metabolism of these materials. It is further argued that understanding the amorphous and disordered state of materials may be key to understanding a range of catalytic reactions; from clean energy reactions to the biological systems that underpin life's existence.

A green and facile direct ink writing technique for preparation calibration standards in laser ablation inductively coupled plasma mass spectrometry analysis

BackgroundLaser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful tool for microanalysis of solid materials. Nevertheless, one limitation of the method is the lack of well-characterized homogeneous reference materials (RMs), such as BaF2 crystal and BaCO3 ceramics samples, making direct quantification difficult. This work presents a novel Direct Ink Writing (DIW) method to produce RMs for microanalysis. The Mg, Cr, Fe, Co, Ni, Cu, Y, Mo, Pr, Gd, Dy, Ho, Er, Tm, Yb, and Lu solutions were gravimetrically doped into BaCO3 by mixing with the dispersant and then cured with DIW techniques. (94) ResultsBaCO3 powder was combined with a dopant analyte to produce a printable slurry, aided by the use of a dispersant and cellulose. The resulting mixture was then printed using DIW equipment. The retention rates of the doped elements were investigated by internal and external standard method, and the results showed that they were completely dispersed in the solid material. After further optimization, it was found that there was no significant heterogeneity among the printed samples. LA-ICP-MS was used to analyze printed samples, to evaluate micro-scale homogeneity. The mass concentration of the doped element was determined by ICP-MS, verify its move closer to nominal value. Compared with the traditional reference materials preparation methods, the DIW technology greatly increased the sample homogeneity and the accuracy of the desired concentration. (132) SignificanceAs far as we know, there are few reports on the application of DIW method to prepare calibration standards. In brief, it is proved that the proposed method of preparing calibration standard by DIW technique to quantify analytes is valid and robust. This procedure provides great potential for LA-ICP-MS in-situ analysis in the field of well-prepared products, such as ceramic and crystal samples.(63)

Eco-Friendly Spiking Approach Based on Microfluidics for Preparation of Matrix Reference Materials

Eco-Friendly Spiking Approach Based on Microfluidics for Preparation of Matrix Reference Materials

Experimental and numerical investigation on latent heat/cold stores for advanced pumped-thermal energy storage

Pumped-thermal energy storage plays a pivotal role in large-scale harvesting and utilization for renewable resource endowments with intrinsic properties such as intermittency and instability. Here, we conducted detailed experimental and numerical studies on latent heat/cold stores of Brayton-like pumped-thermal energy storage. A demonstration thermal energy storage system with rated power of 20 kW including phase change materials (PCMs) preparation and structural design of energy storage units is synergistically designed and built. In this paper, the operating mechanism behind the theoretical experiment and control groups that raises the intake temperature through an air heater is uncovered and compared. Moreover, an auxiliary numerical model for further energy and exergy analyses is established to perfect the system-wide assessment. In terms of the first law of thermodynamics, the speed of energy storage and efficiency increase with higher operational pressures. For instance, system properties like roundtrip efficiency can reach up to 0.37 at an operating pressure of 0.7 MPa. As for systematic exergy despite the total destruction of thermal energy storage units amounts to 12.25 kWh the maximum exergy efficiency could reach 0.61 simultaneously.

Facile synthesis of coral-like nitrogen and sulfur co-doped carbon-encapsulated FeS2 for efficient electroreduction of nitrate to ammonia

Electro-reduction of nitrate (NO3–) to ammonia is a promising method to transform the environmental contaminant NO3– to value-added ammonia. Since diverse end-products might be formed and a convenient material preparation process is preferable, it is of great importance to facilely synthesize a high-performance electro-catalyst towards ammonia generation with high selectivity. Herein, a coral-like nitrogen (N) and sulfur (S) co-doped carbon-encapsulated FeS2 composite material (FeS2@NSC) was successfully fabricated for effective electro-reduction of high-concentration of NO3– to ammonia through a simple one-step pyrolysis method. The FeS2@NSC-400 material exhibited remarkable electrocatalytic NH3 production performance with the NH3 yield of 4428.35 μg h−1 cm−2 and NH3 Faraday efficiency of 84.75 % at −1.4 V vs. Ag/AgCl, which outperforms many of the reported electrocatalysts. The unique small cluster coral-like core–shell structure, N, S co-doping and the interaction between inner FeS2 and the outer carbon layer greatly enhanced the electrical conductivity and stability of the material and the adsorption of NO3– and intermediate products, thereby facilitating the electrocatalytic performance of nitrate-to-ammonia. The FeS2@NSC material induced the electrocatalytic reduction of NO3– mainly through direct electron transfer instead of the indirect atomic H* mediation, and the main reduction product NH3 was speculated to derive from the pathway of NO3–* → NO2–* → NO* → HNO* → H2NO* → H2NOH* → NH3.

Efficient Template-Catalyzed In Situ Polymerization for Carbon Xerogels with Large Specific Surface Area and High Adsorption.

The limited specific surface area (SSA), long preparation period, and high cost are significant challenges for carbon xerogels (CXs). To overcome these limitations, we propose an approach to prepare tannin-resorcinol-formaldehyde-based CXs through template-catalyzed in situ polymerization. ZnCl2 acts as a catalyst and significantly accelerates the polymerization reaction through the coordination of Zn2+ to the carbonyl group in formaldehyde, while atmospheric drying instead of special drying and without solvent exchange reduces the preparation period to 24 h. In addition, ZnCl2 acts as an activator for the formation of many pores. Plant-derived tannins not only reduce the preparation cost but also regulate the pore structure. The resulted CXs with hierarchical porous structures show an optimal SSA of 1308 m2/g, high adsorption capabilities (for cationic, nitrosoaniline dyes, metal, and nonmetallic ions, especially for methylene blue with 454.93 mg/g), low shrinkage down to 10%, and reusability with 92.9% retention after 5 cycles. This work provides a promising and cost-effective method for the large-scale preparation of porous carbon materials with large SSA, offering potential applications in adsorption, energy storage, and catalysis.

Preparation of Positive and Negative Composite Electrode Materials for High-Performance Aqueous Asymmetric Supercapacitor by a Sequential Two-Step Reaction

Preparation of Positive and Negative Composite Electrode Materials for High-Performance Aqueous Asymmetric Supercapacitor by a Sequential Two-Step Reaction

Model Prediction and Experimental Validation of Transverse Permeability of Large-Tow Carbon Fiber Composites.

Large-tow carbon fiber (LCF) meets the low-cost requirements of modern industry. However, due to the large and dense number of monofilaments, there are problems with uneven and insufficient infiltration during material preparation. The permeability of large-tow carbon fibers can be used as a two-scale expression of resin flow during infiltration, making it an important factor to consider. This paper provides support for the study of pore formation. A two-dimensional model of randomly bundled large-filament carbon fibers is generated based on scanning electron microscope (SEM) maps. Microstructure size parameters are obtained, and a semi-analytical model of the transverse permeability of large-filament-bundled carbon fibers is established. Permeability values are then obtained. The analysis shows that the monofilaments in the tow are arranged randomly, and their periodic arrangement cannot be used to calculate permeability. Additionally, the number of monofilaments in a carbon fiber tow of the same volume fraction affects the permeability of the tow. Therefore, the permeability model of large-tow carbon fibers is reliable.