One-step Processes Research Articles

Crystallization of high gyrotropy garnets with decreasing thermal processing budgets as analyzed by electron backscatter diffraction

Rare-earth iron garnets with large magnetic gyrotropy, made with reduced thermal budgets, are ideal magneto-optical materials for integrated isolators. However, reduced thermal budgets impact Faraday rotation by limiting crystallization, and characterization of crystallinity is limited by resolution or scannable area. Here, electron backscatter diffraction (EBSD) is used to measure crystallinity in cerium substituted yttrium- and terbium-iron garnets (CeYIG and CeTbIG) grown on planar Si, crystallized using one-step rapid thermal processes, leading to large Faraday rotations > −3500 °/cm at 1550 nm. Varying degrees of crystallinity are observed in planar Si and patterned Si waveguides, and specific dependences of crystallite size are attributed to the nucleation/growth processes of the garnets and the lateral dimensions of the waveguide. On the other hand, a low thermal budget alternative–exfoliated CeTbIG nanosheets–are fully crystalline and maintain high Faraday rotations of −3200 °/cm on par with monolithically integrated thin film garnets.

Highly efficient CsPbBr3@glass@polyurethane composite film as flexible liquid crystal display backlight.

Inorganic lead halide perovskite quantum dots (CsPbX3 QDs (X = Cl, Br, or I)) have attracted more and more attention due to their high absorption coefficient, narrow emission band, high quantum efficiency, and tunable emission wavelength. However, CsPbX3 QDs are decomposed when exposed to bright light, heat, moisture, etc., which leads to severe luminous attenuation and limits their commercial application. In this paper, CsPbBr3@glass materials were successfully synthesized by a one-step self-crystallization method, including melting, quenching and heat treatment processes. The stability of CsPbBr3 QDs was improved by embedding CsPbBr3 QDs into zinc-borosilicate glass. Then, the CsPbBr3@glass was combined with polyurethane (PU) to form a flexible composite luminescent film CsPbBr3@glass@PU. This strategy enables the transformation of rigid perovskite quantum dot glass into flexible luminescent film materials and further improves the photoluminescence quantum yield (PLQY) from 50.5% to 70.2%. The flexible film has good tensile properties, and its length can be strained 5 times as long as the original length. Finally, a white LED was encapsulated by combining CsPbBr3@glass@PU film and red phosphor K2SiF6:Mn4+ with a blue LED chip. The good performance of the obtained CsPbBr3@glass@PU film indicates that it has potential application in flexible liquid crystal displays (LCDs) as a backlight source.

Hydrolytic enzyme screening and carotenoid production evaluation of halophilic archaea isolated from highly heavy metal-enriched solar saltern sediments.

This paper aimed to screen the enzymatic activities and evaluate the carotenoid production level of twenty-two halophilic archaea isolated from Sfax solar saltern sediments. The molecular identification performed by sequencing the 16S rRNA genes showed that all strains have a high similarity degree (99.7-100%) with Halobacterium salinarum NRC-1. The strains were screened for the presence of eight hydrolase activities using agar plate-based assays. The most detected enzyme was gelatinase (77.27% of total strains), followed by protease (63.63%) and amylase activities (50%). The carotenoid production yields of the strains ranged between 2.027 and 14.880mg/l. The UV-Visible spectroscopy of pigments revealed that it was a bacterioruberin type. When evaluated and compared to the standard β-carotene, the antioxidant capacities of these pigments showed a scavenging activity of more than 75% at a concentration of 5μg/ml for three strains (AS16, AS17, and AS18). Then a sequence of one-step optimization processes was performed, using the one-factor-at-a-time approach, to define the optimum conditions for growth and carotenoid production of the highest carotenoid producing strain (AS17). Different environmental factors and nutritional conditions were tested. Variations in these factors were found to deeply influence growth and carotenoid production. A maximum carotenoid production (16.490mg/l), higher than that of the control (14.880mg/l), was observed at 37°C, pH 7, 250g/l of salinity, with 80% air phase in the flask at 110rpm, in presence of light and in culture media containing (g/l) 10, yeast extract; 7.5, casamino acid; 20, MgSO4; 4, KCl; and 3, trisodium citrate.

Enhancing the production of small molecular products from pubescens via stepwise pyrolysis process

Pyrolysis of pubescens pretreated by torrefaction was investigated by one-step and stepwise processes. The cumulative yield of small molecular compounds reached up to 19.6 wt% via stepwise processing, yielding monosaccharides (1.49 wt%), carboxylic acids (5.20 wt%), furans (3.97 wt%) and monophenols (8.94 wt%), which is higher than the corresponding value of 12.39 wt%, with 0.65 wt%, 6.15 wt%, 1.05 wt% and 4.54 wt% of the four kinds of species obtained respectively, from one-step pyrolysis. Production of carboxylic acids could be enhanced in the temperature range of 200–320 °C via dehydration of holocellulose and cleavage of acetyl group in lignin, while the acquisition of furans could be promoted in the range of 240–360 °C via further dehydration of the units of holocellulose. In the temperature range of 240–440 °C, the cleavage of β-1,4-glycosidic linkages in cellulose and glycosidic bonds in hemicellulose enhanced the yield of monosaccharides. Furthermore, the formation of monophenols from the decomposition of H, G, and S units of lignin was enhanced via cleavage of C1-Cα, Cα-Cβ, Cβ-Cγ, Cα-OH, C-O-H(R), etc. in saturated and unsaturated regions, accompanied by elimination, dehydration reactions. With stepwise processing, the corresponding carbon content in the pyrolyzed residue was enriched, resembling the elemental composition of Bituminous coal. Moreover, the relationship between small molecular weight compounds and oligomers has been probed.

Assessing the economic and environmental sustainability of bio-olefins: The case of 1,3-butadiene production from bioethanol

There is a growing interest in the production of biobutadiene from bioethanol, but it is not possible to conclude from the literature which conversion process, either by one or two reaction steps, is preferred since there is a lack of works comparing their economic and environmental performances. The aim of this work is to perform that comparison so it can serve as a guide for decision making by future investors as well as set future research needs that can improve the technology. Assuming production in Brazil from sugarcane ethanol, technoeconomic and lifecycle assessments were performed from process simulations, and the reliability of the results was studied with uncertainty analyses. The comparison reveals that the one-step process should be preferred because of its better economic and environmental performance. Biobutadiene from ethanol is not cost competitive against naphtha-derived butadiene (probability of positive net present value is 11–17% for one-step process scenarios and 5% for the two-step process scenarios) but producing biobutadiene from ethanol in Brazil leads to significant reductions in emissions of CO2 compared to naphtha-derived butadiene (102–103% and 7.6–52.4% for one- and two-step process scenarios, respectively). A critical issue for the cost competitiveness of biobutadiene is that the CO2 saved can be sold in an international carbon emission trading market. In that case, the one-step processes would be much more favored. Future research is needed concerning the development of highly selective two-step catalysts operating in less energy-demanding conditions so that two-step processes can compete with one-step processes.

Metabolic engineering of Escherichia coli for direct production of vitamin C from D-glucose

BackgroundProduction of vitamin C has been traditionally based on the Reichstein process and the two-step process. However, the two processes share a common disadvantage: vitamin C cannot be directly synthesized from D-glucose. Therefore, significant effort has been made to develop a one-step vitamin C fermentation process. While, 2-KLG, not vitamin C, is synthesized from nearly all current one-step fermentation processes. Vitamin C is naturally synthesized from glucose in Arabidopsis thaliana via a ten-step reaction pathway that is encoded by ten genes. The main objective of this study was to directly produce vitamin C from D-glucose in Escherichia coli by expression of the genes from the A. thaliana vitamin C biosynthetic pathway.ResultsTherefore, the ten genes of whole vitamin C synthesis pathway of A. thaliana were chemically synthesized, and an engineered strain harboring these genes was constructed in this study. The direct production of vitamin C from D-glucose based on one-step fermentation was achieved using this engineered strain and at least 1.53 mg/L vitamin C was produced in shaking flasks.ConclusionsThe study demonstrates the feasibility of one-step fermentation for the production of vitamin C from D-glucose. Importantly, the one-step process has significant advantages compared with the currently used fermentation process: it can save multiple physical and chemical steps needed to convert D-glucose to D-sorbitol; it also does not involve the associated down-streaming steps required to convert 2-KLG into vitamin C.

Highly efficient photocatalytic H2O2 generation over dysprosium oxide-integrated g-C3N4 nanosheets with nitrogen deficiency

The increasing global crisis considers energy as the fundamental cause to conduct extensive research work to find clean alternative methods with high capabilities such as H2O2 synthesis. Photocatalytic H2O2 production can tackle this growing issue by maintaining environmental remediation. In this work, dysprosium oxide (Dy-oxide)-integrated g-C3N4 has been synthesized and characterized with XRD, SEM, TEM, XPS, EPR, DRS, PL, and electrochemical analyses. Simulated solar light irradiation implemented photocatalytic H2O2 production using the as-prepared catalysts. The facile preparation technique in the Ar atmosphere raises more N deficiency in the g-C3N4 matrix. N-deficient g-C3N4 nanosheets with an exceptionally high photocatalytic performance can be further enhanced by integrating well-dispersed Dysprosium oxide (Dy2O3) particles onto g-C3N4. This study reports bandgap narrowing and various surface defects on g-C3N4 with trace amounts of Dy2O3. Undoped g-C3N4 (Dy0) yielded 20.27 mM⋅g−1⋅h−1, while the optimized photocatalyst Dy15 showed high performance of H2O2 production up to 48.36 mM⋅g−1⋅h−1. It is approximately 2.4 times higher than the pristine g-C3N4. Dy15 proves the positive impact of Dy-oxide on enhancing the N-deficient g-C3N4 performance towards photocatalytic H2O2 production. This work highlights the oxygen reduction reaction (ORR) through a mixed pathway of well-known two-step one-electron and one-step two-electron processes in H2O2 generation.

High-Resolution 3D Printing Fabrication of a Microfluidic Platform for Blood Plasma Separation.

Additive manufacturing technology is an emerging method for rapid prototyping, which enables the creation of complex geometries by one-step fabrication processes through a layer-by-layer approach. The simplified fabrication achieved with this methodology opens the way towards a more efficient industrial production, with applications in a great number of fields such as biomedical devices. In biomedicine, blood is the gold-standard biofluid for clinical analysis. However, blood cells generate analytical interferences in many test procedures; hence, it is important to separate plasma from blood cells before analytical testing of blood samples. In this research, a custom-made resin formulation combined with a high-resolution 3D printing methodology were used to achieve a methodology for the fast prototype optimization of an operative plasma separation modular device. Through an iterative process, 17 different prototypes were designed and fabricated with printing times ranging from 5 to 12 min. The final device was evaluated through colorimetric analysis, validating this fabrication approach for the qualitative assessment of plasma separation from whole blood. The 3D printing method used here demonstrates the great contribution that this microfluidic technology will bring to the plasma separation biomedical devices market.

Sulfurization of nickel–cobalt fluoride decorating ammonia ions as efficient active material of supercapacitor

Nickel cobalt fluoride decorating ammonia ions (NCNF) with excellent energy storage ability is proposed by incorporating ammonia fluoride during synthesizing ZIF-67 in our previous work. It is necessary to modify NCNF for achieving better energy storage ability and widen its application. In this study, sulfurization and copper decoration are firstly adopted to enhance energy storage ability of NCNF. Without Cu decoration, aggregations completely convert to separated nanoparticles at sulfurization temperature of 160°C, which also shows partial conversion of NCNF to cobalt sulfide. The highest specific capacitance (CF) of 1666.1 ​F/g (277.7 mAh/g) is achieved for optimized NCNF-derived sulfide, and untreated NCNF electrode only shows a CF value of 519.8 ​F/g (277.7 mAh/g), due to partial sulfurization of the former case with high electrocapacitive property of NCNF and high electrical conductivity of sulfide. Copper is then incorporated using one-step and two-step hydrothermal processes. However, the best performed copper-decorated NCNF-derived sulfide electrode only shows a CF value of 508.5 ​F/g (84.8 mAh/g), due to the dominated formation of copper sulfide and limited appearances of cobalt sulfide and NCNF. A symmetric energy storage device comprising optimized NCNF-derived sulfide electrodes presents a maximum energy density of 8.64 ​Wh/kg at 2.16 ​kW/kg and high capacitance retention of 125% after 13,000 cycles.

Separation of calcium chloride from waste acidic raffinate in HCl wet process for phosphoric acid manufacture: Simulated and experimental study

Phosphoric acid manufacture by HCl wet process is a phosphogypsum-free route, which is promising for replacing traditional H2SO4 wet process. However, large amount of CaCl2-containing acidic raffinate was discharged after solvent extraction of H3PO4. In this study, pure CaCl2·2H2O was recovered from the raffinate. The ionic forms and residual amount changes with the pH rise in the raffinate was first simulated by Visual MINTEQ software, and found the precipitation for the components was in the following sequential order of Si>F>P>Al>Cr>Pb≈Mg. Based on the calculation, one-step and multi-steps neutralization processes were designed for separation of impurities. Feed grade calcium hydrophosphate can be separated from the raffinate by multi-steps neutralization. A well-crystallized CaCl2·2H2O assaying 98.9 wt% was obtained after evaporative crystallization of the fluorine-depleted solution. Combined with our previous studies on the phosphate ore digestion and H3PO4 solvent extraction, a complete HCl wet process for H3PO4 manufacture was established.

Microstructure and mechanical property of in-situ synthesized SiC–TiB2 porous ceramic as a function of TiB2 content

A convenient and promising one-step manufacturing processes was successfully developed to fabricate SiC–TiB2 porous ceramics. TiO2, B4C and sucrose were used as raw materials for in-situ generation of TiB2 phase, which promoted skeleton grain bonding and achieved highly interconnected pores simultaneously. The effect of different TiB2 volume fractions on porous structures, pore parameters, and mechanical properties was studied. SiC–TiB2 porous ceramics were obtained with porosities ranging from 36.2% to 41.9%, pore sizes ranging from 2 μm to 10 μm, and high compressive strength up to 169.5 MPa. Apart from the total porosity, TiB2 content, as well as pore/skeleton characteristics, were demonstrated as important factors affecting the mechanical properties. Hence, based on the strength-porosity relationship, an extended equation was proposed for modelling and optimizing the mechanical properties of biphasic porous ceramics.

Processing of Lead Halide Perovskite Thin Films Studied with In-Situ Real-Time X-ray Scattering.

Lead halide perovskites have been of paramount interest for solution-processable solar cells, reaching power conversion efficiencies larger than 25%. In this spotlight, we will provide a systematic overview of the influence of different solution-based processing routes of lead halide perovskites on their phase transformation and conversion as revealed through in-situ X-ray-scattering experiments. These experiments were performed in conditions closely mimicking thin film processing methods and conditions used for thin film solar cell device fabrication and therefore provide critical information about the mechanism of the phase transformation, its onset, the kinetics, as well as the emergence and disappearance of various (meso)phases along the way. The measurements capture the overall solidification and conversion process of lead halide perovskite inks into solid films via so-called one-step and two-step spin-coating processes as well as blade coating and hot casting. Processing routes are applied to films based on basic components as well as mixtures of different anions and cations, solvents, and antisolvents, all of which deeply affect the thin film microstructure and morphology of the light-absorbing semiconductor and associated solar cell devices.

A photo-elutable and template-free isothermal amplification strategy for sensitive fluorescence detection of 5-formylcytosine in genomic DNA

5-Formylcytosine (5fC), as an important epigenetic modification, plays a vital role in diverse biological processes and multiple diseases by regulating gene expression. Owing to the extremely low abundance of 5fC in all mammalian tissues and high structural similarity with other cytosine derivatives, the precise and sensitive detection of 5fC is challenging. Herein, a photo-elutable and template-free isothermal amplification strategy has been proposed for the sensitive detection of 5fC in genomic DNA based on 5fC-specific biotinylation, enrichment, photocleavage, and terminal deoxynucleotidyl transferase (TdT)-assisted fluorescence signal amplification, which is termed 5fC-PTIAS. By introducing the highly specific chemolabeling and the one-step photoelution processes, this strategy possesses a minimal nonspecific background as well as a much higher amplification efficiency. With the high signal-to-noise ratio, this strategy can achieve the accurate quantification of 5fC in various biological samples including mouse brain, kidney, and liver, with a limit of detection (LOD) of 0.025‰ in DNA (S/N = 3). These results not only confirm the widespread distribution of 5fC but also indicate its significant variation in different tissues and ages. The bisulfite- and mass spectrometry-free strategy is highly sensitive, selective, and easily mastered, holding great promise in detecting other epigenetic modifications with much lower levels.

Continuous Casting Practices for Steel: Past, Present and Future

This historical review of casting methods used to produce sheets of steel for automobiles, household products, rocket bodies, etc., all point toward the development of one-step commercial processes, which are capable of casting liquid steel directly into a final sheet product. Progress towards this goal is confirmed by successful advances being made, but there remain major difficulties in reaching it. We concur that the conventional continuous casting method remains the current process of choice for highest-quality steel sheet products, but the ESP TSC (Endless Strip Production—Thin Slab Caster) approach is now highly competitive. Similarly, the original goal of Sir Henry Bessemer to produce a direct strip-making twin-drum caster, in 1856, finally came to lasting commercial fruition at CASTRIP/NUCOR. Nonetheless, a newer approach, promoted by Salzgitter, termed DSP (Direct Strip Production), or promoted by MMPC/MetSim as HSBC (Horizontal Single Belt Casting), has several advantages over CASTRIP in terms of microstructures and productivity. As such, the pros and cons of current methods are reviewed within this brief history of casting.

Modification of Orange Bagasse with Reactive Extrusion to Obtain Cellulose-Based Materials

Orange bagasse (OB) could be considered a sustainable, renewable, and low-cost biomass for the extraction of cellulose. In this context, reactive extrusion can be considered an excellent, eco-friendly, alternative process for the extraction of cellulose from lignocellulosic materials. Thus, the present study aimed to obtain cellulose-based materials with a reactive extrusion process and also to investigate the impact of pectin on the delignification process. Two groups of samples (OB and depectinizated OB) were submitted to extrusion with sulfuric acid or sodium hydroxide in one-step processes. The cellulose content of extruded materials was highly affected by pectin content in the raw material; the thermal profile (TGA curves) and crystallinity also changed. The cellulose content of modified materials ranged from 18.8% to 58.4%, with a process yield of 30.6% to 79.2%. The alkaline reagent provided the highest cellulose content among all extrusion treatments tested, mainly for OB without pectin. The extrusion process was considered an efficient and promising process for extracting cellulose from citrus residue. Materials produced in this study can be used as sources of cellulose fiber for various products and processes, such as in the food industry, fermentation substrates, or refined applications after subsequent treatments.

On the equivalence of operator and combinatorial approaches for onestep random Markov processes

Herein, for one-step random Markov processes the comparison of the operator and combinatorial methods based on the use of functional integrals is performed. With the combinatorial approach, the transition from the stochastic differential equation to the functional integral is used. This allows us to obtain the expression for the mean population size in terms of the functional integral. With the operator approach, the transition to the functional integral is performed via the creation and annihilation operators. It is shown that the mean values calculated using the functional integrals arising in the combinatorial and operator approaches coincide.

Synthesis of high thermal stability Polypropylene copolymers with pyrrole functionality

Functionalization of polyolefins has been proven to be a promising way to fine-tune their properties, among which, improved thermal stability is crucial for high performance in end-use applications. However, it still remains in academia, as some important issues still need to be resolved for this methodology to move towards industrial scale-up, the most important of them being the development of one-step processes. This work focuses specifically on the development of a single-step functionalization route for the synthesis of high thermal and thermo-oxidative stability polypropylenes. The synthesis of Polypropylene (PP) bearing N-alkyl groups by copolymerization via metallocene catalysis is studied. The copolymers are found to exhibit high thermo-oxidative stability, whose origin appears to be based, not only on the radical scavenging activity of N-alkyl moieties, but also on the associated crosslinking that takes place under processing conditions. Some exploratory results from a solid-state 13CNMR analysis provide support to a radical mechanism, involving coupling between benzyl-like pyrrolyl species.

Sensitivity Control of Hydroquinone and Catechol at Poly(Brilliant Cresyl Blue)-Modified GCE by Varying Activation Conditions of the GCE: An Experimental and Computational Study

The poly(brilliant cresyl blue) (PBCB)-modified activated glassy carbon electrode (AGCE) shows the catalytic activity toward the oxidation of hydroquinone (HQ) and catechol (CT). The modified electrode can also separate the oxidation peaks of HQ and CT in their mixture, which is not possible with bare GCE. These properties of the modified electrode can be utilized to fabricate an electrochemical sensor for sensitive and simultaneous detection of HQ and CT. In this study, an attempt is made to control the sensitivity of the modified electrodes. This can be accomplished by simply changing the activation condition of the GCE during electropolymerization. GCE can be activated via one-step (applying only oxidation potential) and two-step (applying both oxidation and reduction potential) processes. When we change the activation condition from onestep to twosteps, a clear enhancement inpeak currents of HQ and CT is observed. This helps us to fabricate a highly sensitive electrochemical sensor for the simultaneous detection of HQ and CT. The molecular dynamics (MD) simulation is carried out to explain the experimental data. The MD simulations provide the insight adsorption phenomena to clarify the reasons for higher signals of CT over HQ due to having meta-position –OH group in its structure.

Effect of magnetite on the catalytic oxidation of polycyclic aromatic hydrocarbons in fly ash from MSW incineration: A comparative study of one-step and two-step hydrothermal processes

Polycyclic aromatic hydrocarbons (PAHs), many of which are carcinogenic, teratogenic, and mutagenic, exist in fly ash (FA) produced from municipal solid waste incineration (MSWI). Hydrothermal treatment (HT) is an efficient approach to remove PAHs from MSWI FA. Here, magnetite (Fe3O4) was used as the catalyst and hydrogen peroxide (H2O2) as the oxidant for one-step and two-step catalytic hydrothermal methods. When the magnetite dosage increased to 15 wt%, the maximum degradation rates of PAHs were 84.36% and 92.51%, respectively; however, the toxicity equivalent quantity (TEQ) degradation rates of the PAHs both increased upon increasing the magnetite dose. At 20 wt% Fe3O4, the maximum TEQ degradation rates of the PAHs were 93.29% and 97.76%, respectively. The reaction between OH and PAHs is non-selective, which means that LMW, MMW, and HMW PAHs were all degraded. The decrease in TEQ was mainly due to the degradation of HMW PAHs, i.e., those with five rings. Under the same Fe3O4 dose, oxidant dose, and reaction time, the detoxification of PAHs by the two-step method was significantly better than that of the one-step method, possibly because the two-step method more effectively produced OH. The first step degraded more than 90% of PAHs, and the residual PAHs in the HT products of the first step limited the utilization of the oxidant during the second step. The minerals in the HT products implied that the two-step hydrothermal method not only produced more OH, which reacted with PAHs, but also generated metal-magnetite substitution, which affected its surface reactivity during heavy metal adsorption and catalysis. These results revealed that both magnetite and the two-step hydrothermal treatment degraded PAHs. 20 wt% magnetite was the optimal amount during the two-step hydrothermal catalytic oxidation of MSWI FA.

Nanofibrillated Cellulose Extracted by Enzymatic Hydrolysis Followed by Mechanical Fibrillation

ABSTRACT In a comparison with certain one-step processes, enzymatic hydrolysis followed by mechanical defibrillation may avoid the use of nonrenewable resources, mitigate the generation of toxic effluents, and reduce the energy consumption related to a single mechanical process. In the present study, bleached and unbleached hardwood pulps were employed as raw materials for producing nanofibrillated cellulose (CNF) using a two-step process, in which a cellulase enzyme was inoculated to act as a pretreatment for a subsequent grinding process. The obtained CNF reached high crystallinity indexes (above 70%) and high thermal stability (degradation onset temperatures around 200°C). Increases in enzyme concentration yielded decreases in diameter and increases in both thermal stability and crystallinity index. These findings indicated that the enzymatic hydrolysis used as a pretreatment to a further grinding process can allow the production of valuable CNF-based products.