The most representative technology of 3D printing is fused deposition modeling (FDM). To improve the printing accuracy of FDM technology, this paper first takes the outlet diameter, angle of convergence, and rectifier section length of the nozzle as the influencing factors. It takes the melt outlet speed stability, viscosity, and outlet pressure as the indexes to design the orthogonal test. Then, COMSOL Multiphysics fluid−solid coupling simulation was used to simulate and analyze the structural characteristics of the 3D printer nozzle, and the range analysis method was used to analyze the data. Finally, the two-phase flow combination was used to simulate the morphological characteristics of the melt flowing out of the nozzle. The results show that the simulation results of the two materials are similar. As the nozzle diameter decreases, the melt pressure decreases, the velocity increases, and the viscosity decreases. For PLA wire rods, the optimal structure of the nozzle is that the ou... [more]

This paper presents a unique approach to generate a number of cutting knowledge blocks for the surface roughness analysis of the drilling process for carbon-fiber-reinforced polymer composite (CFRP) materials. The influence of drilling on the surface quality of woven CFRP materials was investigated experimentally. The CFRP material (0/90° fiber orientation) was drilled at different cutting parameters and the surface roughness of the hole was measured. A set of tests was carried out using carbide drills of 8 mm in diameter at 50, 70, and 90 m/min cutting speeds, 2, 3, and 4 flute numbers, and 0.2, 0.3, and 0.4 mm/rev feed rates. The Simulated Annealing (SA) and Genetic Algorithm (GA) methods were used for optimization. Based on the experimental findings and optimization techniques applied, optimal cutting parameters were derived, which were subsequently adjusted to enhance surface quality. Overall, the cutting parameters are carefully optimized to achieve good surface roughness quality... [more]

During the drilling of ultra-deep wells, gas kick often occurs, influenced by the complex void pressure profile. The accurate description of particle settling behavior in the gas−liquid mixture is of great significance to effectively deal with gas kicks and ensure drilling safety. In this study, the gas−liquid two-phase annulus flow with different gas volume fractions is created through the transparent annular pipe, constant pressure air pump, and gas flowmeter. High-speed photography is used to record and analyze the sedimentation of particles in gas−liquid mixtures. This study is based on 288 tests. The main parameters in this experiment include the particle Reynolds number, the gas fraction, and liquid viscosity. The effects of wall and gas fraction on the drag coefficient were analyzed. The correlation of particle terminal settling velocity was established. The results obtained show a correlation with average absolute errors (AAE) of 10.7%. This study reveals the settling character... [more]

Vanillin (4-hydroxy-3-methoxybenzaldehyde) is the main component of natural vanilla and a relevant substance in the flavoring and aromatic industries. This study presents a kinetic model to explain both vanillin and vanillic acid concentrations achieved in the alkaline oxidation of pine kraft lignin. Considering that they come from the same precursors, this approach allows an understanding of vanillin production with reaction conditions that minimize the vanillic acid pathway directly from the lignin oligomers, thus maximizing vanillin production. This study involves the effects of oxygen partial pressure, temperature, and the presence or absence of a catalyst (CuSO4 and Fe2(SO4)3 mixture) on the vanillin and vanillic acid yields. An adapted reactor (M/K Systems Inc., Williamstown, MA, USA) with a recirculation and spray liquids system was used in the experiments. The experiments were performed using one liter of a solution of NaOH 2 M and 60 g of lignin. During the lignin oxidation re... [more]

The application of organometallic materials as anodes in fuel cell devices has experienced a notable increase in recent years. However, the use of POCOP pincer complexes remains scarcely explored despite their great relevance in catalysis. Thus, in this work, the electrocatalytic activity to methanol in alkaline media of three Ni(II)-based POCOP pincer complexes—[NiCl{C6H2-4-OH-2,6-(OPiPr2)2}] (a1), [NiCl{C6H2-4-OH-2,6-(OPtBu2)2}] (a2), and [NiCl{C6H2-4-OH-2,6-(OPPh2)2}] (a3)—will be discussed. The complexes were use as modifiers of carbon paste electrodes that were evaluated using cyclic voltammetry considering diverse factors, such as the absence and presence of MeOH, diverse proportions (% w/w) of the complex in the electrode, scan rate, and different MeOH concentrations. Results indicated the presence of a redox pair Ni(II)/Ni(III) with a quasi-reversible behavior in all complexes, the anodic peak currents of which were proportional to the increase in MeOH concentrations (0.05−0.3... [more]

Cellobionic acid (CBA) can be obtained through the oxidation of cellobiose, the monomer of cellulose. CBA serves as a plant-based alternative to its stereoisomer lactobionic acid, which is used in the pharmaceutical, cosmetic, and food industries. Gluconobacter oxydans is a well-established whole-cell biocatalyst with membrane-bound dehydrogenases (mDH) for regio-specific oxidations. As G. oxydans wildtype cells show low cellobiose oxidation activities, the glucose mDH from Pseudomonas taetrolens was overexpressed in G. oxydans BP9, a multi mDH deletion strain. Whole-cell biotransformation studies were performed with resting cells of the engineered G. oxydans in stirred tank bioreactors. Initial biomass specific cellobionate formation rates increased with increasing cellobiose concentrations up to 190 g L−1, and were constant until the solubility limit. The maximal volumetric CBA formation rates and the oxygen uptake rates increased linearly with the concentration of engineered G. oxyd... [more]

Photocatalysis, mainly using TiO2 as a catalyst, has emerged as a promising method to address the issue of wastewater treatment. This study explores the enhanced photocatalytic activity of TiO2 through the introduction of reduced graphene oxide (rGO) and cadmium sulfide (CdS) as selective metal dopants. The incorporation of rGO and CdS into the TiO2 lattice aims to optimize its photocatalytic properties, including bandgap engineering, charge carrier separation, and surface reactivity. The unique combination of CdS and rGO with TiO2 is expected to boost degradation efficiency and reduce the reliance on expensive and potentially harmful sensitizers. This experimental investigation involves the synthesis and characterization of TiO2-based photocatalysts. The photocatalytic degradation of methyl orange (MO) and methylene blue (MB) was assessed under controlled laboratory conditions, studying the influence of metal dopants on degradation kinetics and degradation efficiency. Furthermore, the... [more]

This study investigates the impact of plasma gradient modification and gradient illumination on the optoelectronic properties of buckypaper (BP), a flexible and large-scale material composed of multi-walled carbon nanotubes (MWCNTs). The BP samples were subjected to argon ion plasma treatment at varying power levels and durations, thereby creating different carrier concentration gradients on the surface. The photovoltage and photocurrent responses of the samples were then measured under uniform full illumination and gradient illumination conditions. The findings revealed that both plasma gradient modification and gradient illumination significantly enhanced the optoelectronic performance of BP. Notably, the combined application of these two methods yielded superior results compared to the application of either method alone. Specifically, the optimal plasma power for improving BP was found to be 20 W. Under conditions of plasma gradient modification and gradient illumination, a photovol... [more]

Anammox bacteria were embedded with different mass fractions of polyvinyl alcohol (PVA), polyethylene glycol (PEG) and water-based polyurethane (WPU) materials. The embedded immobilized pellets with different particle sizes of about 2.8−3.2 mm were prepared. The effects of the mass fraction of the embedding material (PVA 6−12%, PEG 6−9%, WPU 10%) and the concentration of activated carbon added in the embedding process (0−4%) on the pellet was investigated. The performance of pellet formation, sedimentation rate, mechanical strength, expansion coefficient, and elasticity were compared and analyzed under different immobilization conditions, and the parameters of each embedding step were optimized. Anammox immobilized pellets prepared with 10% polyvinyl alcohol (PVA), 2% sodium alginate (SA), and 2% powdered activated carbon were proposed. The effects of salinity on anammox were investigated through a batch test, and the optimal reaction conditions were selected to carry out the operation... [more]

Currently, the development of innovative materials for the treatment of various diseases is highly interesting and effective. Additionally, in recent years, environmental changes, including the search for a sustainable world, have become the main goal behind developing sustainable and suitable materials. In this context, this research produced innovative hydrogels that incorporate cellulose nanocrystals and nanofibres from underutilised fibres from a semiarid region of Brazil; the hydrogels were loaded with vitamin D to evaluate controlled drug release for the treatment of diverse diseases. Spectroscopic (FTIR, Raman, UV−VIS), X-ray diffraction, zeta potential and morphology (SEM, TEM) analyses were used to characterise these hydrogels. In addition, biocompatibility was assessed using a resazurin assay, and the in vitro kinetic accumulative release of vitamin D was measured. The results showed that nanocrystals and nanofibres changed the structure and crystallinity of the hydrogels. In... [more]

Pore and fracture structure heterogeneity is the basis for coalbed methane production capacity. In this paper, high-pressure mercury intrusion test curves of 16 coal samples from the Taiyuan Formation in the Linxing area are studied. Based on the fractal dimension values of mercury intrusion and retreat curves, the correlation between the two different fractal parameters is studied. Then, the permeability variation of different types of coal samples is studied using overlying pressure pore permeability tests. The correlation between the permeability variation of coal samples and dimension values is explored, and the results are as follows. (1) Based on porosity and mercury removal efficiency, all coal samples can be divided into three types, that is, types A, B, and C. Among them, Type A samples are characterized by lower total pore volume, with pore volume percentages ranging from 1000 to 10,000 nm not exceeding 15%. (2) During the mercury injection stage, both the M-model and S-model... [more]

Metformin, widely prescribed to treat type 2 diabetes for its effectiveness and low cost, has raised concerns about its presence in aqueous effluents and its potential environmental and public health impacts. To address this issue, xerogels were synthesized from resorcinol and formaldehyde, with molar ratios ranging from 0.05 to 0.40. These xerogels were thoroughly characterized using FT-IR, SEM, TGA, and TEM analyses. Batch adsorption experiments were performed with standard metformin solutions at concentrations of 50 and 500 mg/L, varying pH, and temperature to determine the adsorption isotherms of the synthesized xerogels. The adsorption data revealed a maximum adsorption capacity of 325 mg/g at pH 11 and 25 °C. Quantum chemical calculations revealed that electrostatic interactions govern metformin adsorption onto xerogels. The xerogels’ adsorption capacity was evaluated in competitive systems with CaCl2, NaCl, MgCl2, and synthetic urines. Reuse cycles demonstrated that xerogels cou... [more]

Starch-based biodegradable films are a type of packaging material that can naturally decompose in the environment. Current challenges regarding starch-based film applications are their high solubility and low hydrophobicity. Prior studies have shown that plasma application improves the physical, chemical, and mechanical properties of these films. This work evaluates the plasma application strategy regarding the process stage in which plasma should be applied (starch granule, film-forming solution, or film). Three groups of films were produced: a film produced with the plasma-treated starch, a film produced by subjecting the film-forming solution to plasma treatment, and a plasma-treated film produced with the untreated starch. A 22 face-centered experimental design was applied to each group of films to attain the optimal film of each group. The design consisted of applying plasma at 100, 200, and 300 Hz for 0, 10, and 20 min to each group. The results showed significant differences reg... [more]

The sludge from water treatment plants (WTP) is a waste from the water process. This study evaluated the effect of incorporating water treatment plant (WTP) sludge, replacing the water used in compacted soil−cement mixtures. The materials were characterized by Scanning Electron Microscopy (SEM) associated with Energy Dispersive Spectroscopy (EDS) and Atomic Absorption Spectrometry (AAS). The soil, with the addition of liquid WTP sludge, presented an apparent dry specific weight (ƴd) of 1.77 gf·cm−3, the optimum moisture value in the compaction test of 15%, and the cement contents tested were 7, 11, and 14%. The specimens were molded using a WTP sludge−cement−soil mixture under the conditions mentioned above, and the simple compression results showed values within the range of 2.5 to 9.3 MPa, as specified by the Brazilian Technical Standard (NBR) 8491/2012. The hydraulic conductivity performed on the test specimen after 28 days of curing resulted in a coefficient (k) of 7.49 × 10−9 cm·s... [more]

Molecular dynamics (MD) simulations were performed to investigate the nanoindentation behavior of Al/Mg-layered nanocomposites with varying layer thicknesses and Mg layer orientations in this study. The aim is to understand the weakening mechanisms at low layer thicknesses and the phase transition mechanisms associated with the dislocation slip angle in the Mg layer. Results indicate that the nanoindentation strength of nanocomposites increases with the layer thickness in the range of 1−10 nm, with the strength of 9.5 × 10−7 N at 10 nm being approximately 73% higher than that at 1 nm. This strength increase is mainly attributed to high interfacial stress, the higher percentage of amorphous atoms, weakened interatomic interactions, and the transition of adjacent interfaces to fully coherent interfaces that significantly reduce their ability to hinder dislocations at the low-layer thickness range. Additionally, in the initial deformation process, the hexagonal close-packed (HCP) phase of... [more]

The lithium storage performance of binary transition metal oxide/graphene composites as anode materials has been attracting more interest from researchers, based on the fact that binary transition metal oxides and graphene are expected to create a synergistic effect and exhibit improved lithium storage characteristics. In this work, a NiO-CuO/reduced graphene oxide composite (NiO-CuO/RGO) was prepared by an ultrasonic agitation process. When the NiO-CuO/RGO is applied to the anode material for lithium-ion batteries (LIBs), the batteries display high discharge capacities (at 730 mA h/g after 100 cycles at 100 mA/g), high-rate performance (311 mA h/g with 5000 mA/g), and excellent stable cyclability (375 mA h/g within 2000 mA/g after 400 cycles). Such results indicate that the combination of NiO-CuO and RGO leads to enhanced lithium storage performance, for the RGO sheets inhibit the large volume change of binary NiO-CuO and enhance the fast transport of both lithium ions and electrons d... [more]

Strawberry guava is the fruit of Psidium littorale, which grows in tropical regions. Few studies have examined the hydrophobic compounds and biological activities of this fruit. Therefore, we purified lipophilic compounds of strawberry guava and examined their effects on epidermal and blood vessel barrier functions as well as their anti-melanogenic activity. Lipophilic compounds were isolated by silica gel column chromatography followed by reversed-phase HPLC with MeOH from an EtOH extract of the fruit. Isolated compounds were identified by comparing NMR and MS spectra with those of reference values. The effects of these compounds on epidermal barrier function were evaluated by measuring transepidermal water loss (TEWL) using reconstructed human epidermal keratinocytes (RHEKs). Blood vessel barrier function was examined using dye permeability through human umbilical vein endothelial cell (HUVEC) layers. Anti-melanogenic activity was assessed by theophylline-induced melanogenesis in B16... [more]

Solid crystalline suspensions (SCSs) containing submicron particles were introduced as a competitive solution to increase dissolution rates and the bioavailability of poorly water-soluble drugs. In an SCS, poorly water-soluble drug crystals are finely dispersed in a hydrophilic matrix. Lately, melt milling as an adapted wet milling process at elevated temperatures has been introduced as a suitable batch manufacturing process for such a formulation. In this work, the transfer from batch operation to a two-step continuous process is demonstrated to highlight the potential of this technology as an alternative to other dissolution-enhancing methods. In the first step, a powder mixture of a model drug (griseofulvin) and a carrier (xylitol) is fed to an extruder, where a uniform suspension is obtained. In the second step, the suspension is transferred to a custom-built annular gap mill, where comminution down to the submicron region takes place. The prototype’s design was based on batch grin... [more]

A longstanding concern in plant essential oil extraction is how to optimize extraction efficiency with limited materials. Supercritical CO2 extraction has been proven effective in enhancing the yield and efficiency of extracting plant essential oils. However, the impact of temperature, pressure, and co-solvent content on extracting Hetian rose essential oil remains unclear. There is a lack of research on the influence of pretreatment methods. This study focuses on investigating supercritical CO2 extraction of rose essential oils from Xinjiang Hetian. The research analyzes the effects of pressure and temperature on the extraction rate and validates the efficiency by calculating the solubility of essential oils in supercritical fluid. Under conditions of 35 MPa, 40 °C, 10 L/h, and a particle size of 0.8 mm, this study evaluates the extraction efficiency using Xinjiang Hetian rose materials pretreated with salt solutions at concentrations of 5%, 10%, and 20%, as well as enzyme solutions a... [more]

Sodium borohydride (NaBH4) is a nontoxic and ideal storage material for hydrogen due to its safety and high hydrogen storage capacity. In order to improve the practicality of the sodium borohydride hydrogen production system, we deposited non-precious metal catalytic materials on readily available polymer foams using a simple chemical plating method, developing a suitable 3D catalyst. Its high specific surface area enables it to produce hydrogen at a rate of up to 3.92 L min−1 g−1. Its unique structure gives the catalyst excellent durability. In addition, an efficient NaBH4-based H2 supply system was developed using this catalyst. Co-Cu-B can facilitate stable hydrogen production from NaBH4, yielding a consistent power output ranging from 0 to 100 W. This work provides a new pathway for developing high-efficiency monolithic self-supported catalysts for industrial applications.

A novel, compact, monopole apple-shaped, triple-band metamaterial-printed wearable antenna backed by a uniplanar compact electromagnetic bandgap (UC-EBG) structure is introduced in this paper for wearable wireless and medical body area network (WBAN/MBAN) applications. A tri-band UC-EBG structure has been utilized as a ground plane to minimize the impact of antenna radiation on the human body and improve antenna performance for the proposed wearable antenna. Metamaterial triangular complementary split ring resonators (TCSRRs) are incorporated into the antenna and UC-EBG structure, resulting in a compact UC-EBG-backed antenna with an overall size of 39 × 39 × 2.84 mm3 (0.41 λg × 0.41 λg × 0.029 λg). The printed textile antenna operates at 2.45 GHz for the wireless local area network (WLAN), 3.5 GHz for 5G new radio (NR), and 5.8 GHz for the industrial, scientific, and medical (ISM) bands with improved gain and high-efficiency values. Furthermore, the performance of the antenna is analyz... [more]

Pain, a prevalent clinical symptom, significantly demands attention in the current public health system due to its profound impact on patients’ quality of life, daily activities, and economic circumstances. Despite being a pervasive issue, many forms of pain remain ineffectively addressed, hence posing an enormous burden on patients. Pharmaceutical treatments, the first-line approach for various forms of pain, continue to face considerable challenges due to their limited efficacy, lack of long-lasting effects, and adverse side effects. In recent years, the rapid advancements in science and technology, especially the incorporation of micro and nano technologies across various domains, have accelerated the development of novel therapeutics. This review underscores the merits and drawbacks of different pharmacological strategies for pain management. It focuses on the research progress and applications of poly (lactic-co-glycolic acid)(PLGA) as drug delivery carriers, elucidating their pot... [more]

A large number of construction practice projects have found that there are many joints and microcracks in rock, concrete, and other structures, which cause the complexity of rock mechanical properties and are the main cause of geological or engineering disasters such as earthquakes, landslides, and rock bursts. To establish a rock fracture toughness evaluation method and understand the distribution range of fracture toughness of Longmaxi Formation shale, this study prepared three-point bending semi-circular disk shale samples of Longmaxi Formation with different crack inclination angles. The dimensionless fracture parameters of the samples, including the dimensionless stress intensity factors of type I, type II, and T-stress, were calibrated using the finite element method. Then, the peak load of the samples was tested using quasi-static loading, and the load−displacement curve characteristics of Longmaxi Formation shale and the variation in fracture toughness with crack inclination an... [more]

In this study, two types of recycling scenarios are assessed for spent battery materials using froth flotation. The first is for a single cathode chemistry and would be considered as the most likely scenario for a large battery manufacturer, who takes back their own batteries for reprocessing. The second scenario is for mixed cathode chemistry, and this would be the most likely scenario for regional reprocessing. The mixed spent battery materials assessed in this work were sourced from such an industrial recycling operation in Australia. Good results were obtained for both recycling scenarios. The anode recovery and anode grade in the final concentrate for both materials evaluated were for the single spent battery material 80.1% and 90.3%, respectively, and for the mixed spent battery material, 77.4% and 82.0%, respectively. For the final tailings, the cathode grades for both materials tested were 93.9% and 87.1%, respectively, with the lower grade for the mixed spent battery attribute... [more]

The use of alumina-containing nepheline raw materials as an alternative source of alumina is relevant in the context of the limited bauxite reserves in Kazakhstan. Nepheline processing can result in products such as alumina, sodium and potassium salts, silicate products and rare metals. In terms of economic value, alumina is the most important. This article considers an advanced technology for nepheline processing for the extraction of alumina that is first purified from potassium. The application of calcium sulphate and calcium oxide as additives to the nepheline raw materials is studied. The optimal conditions for two-stage leaching with calcium additives in the form of calcium sulphate and calcium hydroxide are determined.