Pressure Liquid Research Articles

Retention mechanism in slalom chromatography: Perspectives on the characterization of large DNA and RNA biopolymers in cell and gene therapy.

Significant progress has been made in the last two decades in producing small (<2μm), high-purity, and low-adsorption particles, columns and system hardware, for ultra-high pressure liquid chromatography (UHPLC). Simultaneously, the recent rapid expansion of cell and gene therapies for treating diseases necessitates novel analytical technologies for analyzing large (>2 kbp) plasmid double-stranded (ds) DNA (which encodes for the in vitro transcription (IVT) of single-stranded (ss) mRNA therapeutics) and dsRNAs (related to IVT production impurities) biopolymers. In this context, slalom chromatography (SC), a retention mode co-discovered in 1988, is being revitalized using the most advanced column technologies for improved determination of the critical quality attributes (CQAs) of such new therapeutics. In this review, we first recall non-exhaustively the main currently available analytical techniques (enzyme-linked immunosorbent assay (ELISA), agarose gel electrophoresis (AGE), pulse field gel electrophoresis (PFGE), capillary gel electrophoresis (CGE), mass photometry (MP), anion-exchange chromatography (AEX), ion-pairing reversed-phase liquid chromatography (IP-RPLC), hydrophobic interaction chromatography (HIC), size-exclusion chromatography (SEC), hydrodynamic chromatography (HDC), highly converging flow ultra-filtration (HCF-UF), asymmetrical flow field-flow fractionation (AF4), mass spectrometry (MS), and atomic force microscopy (AFM)) for analyzing mixtures containing large nucleic acid biopolymers, while assessing their strengths and weaknesses. We then focus comprehensively on the SC technique, report on its past applications since its birth, and review in detail the history and evolution of the proposed retention mechanisms accounting for the observations made in SC. This includes and emphasizes the latest physico-chemical insights (shear rates in packed HPLC columns, entropic elasticity and relaxation of dsDNA, dsRNA, and mRNA biopolymers) governing the retention behavior of such biopolymers in SC. Finally, based on the recent advancements in understanding the fundamentals of retention in SC, we provide some perspectives and recent proof-of-concept for the analytical characterization by SC of large dsDNAs (plasmid digests, polymerase chain reaction (PCR) verification), the separation of supercoiled/circular and linear dsDNAs (plasmid linearization), the isolation and quantification of large dsRNAs impurities present in mRNA samples produced by IVT, and the differentiation between dsRNA conformers.

Use of laser-ablation inductively-coupled mass spectroscopy for analysis of selenosugars bound to proteins.

We previously used high pressure liquid chromatography (HPLC) coupled with Se-specific inductively coupled plasma mass spectrometry (ICP-MS) and molecule specific (ESI Orbitrap MS/MS) detection to study the increase in liver Se in turkeys and rats supplemented as selenite in high-Se (5 µg Se/g diet) and adequate-Se diets. We found that far more Se is present as selenosugar (seleno-N-acetyl galactosamine) than is present as selenocysteine (Sec) in true selenoproteins. In high-Se liver, the increase in liver Se was due to low molecular weight (LMW) selenometabolites as glutathione-, cysteine- and methyl-conjugates of the selenosugar, but also as high molecular weight (HMW) species as selenosugars decorating general proteins via mixed-disulfide bonds. To demonstrate selenosugar binding to proteins, aqueous liver extracts from animals fed Se-adequate and high-Se were subjected to SDS-PAGE and Native-PAGE with and without pretreatment with β-mercaptoethanol (βME). The separated proteins were then electrophoretically transferred to membranes, and the membranes subsequently were subjected to laser-ablation inductively-coupled mass spectroscopy (LA-ICP-MS) analysis of 78Se profiles. Without βME treatment, 78Se was widely distributed across the molecular weight profile for both SDS-PAGE and Native-PAGE, whereas βME pretreatment dramatically reduced 78Se binding, reducing the profile to true Sec-selenoproteins. This reduction was ∼50% for both high-Se rat and turkey extracts. The increased 78Se in non-βME treated samples was distributed across the full profile. The use of LA-ICP-MS indicates that selenosugar residues are bound to protein subunits of multiple sizes, and that targeted attachment of selenosugars to a single or limited number of protein subunits does not occur.

ABCB1 Polymorphism Is Associated with Higher Carbamazepine Clearance in Children.

The aim of our study was to investigate the role of ABCB1 polymorphism in the pharmacokinetics of carbamazepine (CBZ) in children. The study enrolled 47 Serbian pediatric epileptic patients on CBZ treatment. Genotyping for ABCB1 1236C<T (rs1128503), 2677G<A/T (rs2032582) and 3435C<T (rs1045642) was carried out using the TaqMan method. Steady-state CBZ serum concentrations were available from our previous study, determined by high pressure liquid chromatography (HPLC). The NONMEM software and one-compartment model were used for pharmacokinetic analysis. ABCB1 1236C<T, 2677G<A/T and 3435C<T variations were found at the frequencies of 47.9%, 48.9% and 52.1%, respectively. The equation that described population clearance (CL) was CL (L/h) = 0.175 + 0.0403 × SEX + 0.0332 × ABCB1 + 0.0176 × CYP1A2 + 0.000151 × DD where SEX has a value of 1 if male and 0 if female, ABCB1 has a value of 1 if C-G-C/T-T-T and 0 if any other ABCB1 diplotype, CYP1A2 has a value of 1 if -163A/A and 0 if -163C/C or C/A, and DD is the total CBZ daily dose (mg/day). The presence of the ABCB1 1236T-2677T-3435T haplotype is associated with an increased clearance of CBZ in pediatric epileptic patients.

Refining the Production Date of Historical Palestinian Garments Through Dye Identification

The dyes used to produce two Palestinian garments from the British Museum’s collection attributed to the late 19th–early 20th century were investigated by high pressure liquid chromatography coupled with diode array detector and tandem mass spectrometry (HPLC-DAD-MS/MS). Palestinian embroidery is a symbol of national identity and the topic of scholarly research. However, little attention has been given to the dyes and how these changed with the introduction of new synthetic formulations in the second half of the 19th century. The results revealed the use of natural indigoid blue and red madder (Rubia tinctorum), in combination with tannins. Yellow from buckthorn (probably Rhamnus saxatilis) and red from cochineal (probably Dactylopius coccus) were found mixed with synthetic dyes in green and dark red embroidery threads, respectively. Early synthetic dyes were identified in all the other colours. These include Rhodamine B (C.I. 45170), Orange II (C.I. 15510), Orange IV (C.I. 13080), Metanil Yellow (C.I. 13065), Chrysoidine R (C.I. 11320), Methyl Violet (C.I. 42535), Malachite Green (C.I. 42000), Fuchsin (C.I. 42510), Auramine O (C.I. 41000) and Methyl Blue (C.I. 42780). As the date of the first synthesis of these dyes is known, the production date of the garments was refined, suggesting that these were likely to be produced towards the end of the 1880s/beginning of the 1890s. The continuous use of historical local sources of natural dyes, alongside new synthetic dyes, is of particular interest, adding rightful nuances to the development of textile-making practices in this region.

Phytochemical profile and in vitro evaluation of cassava (Manihot esculenta Crantz) foliage as ruminant feed with/without green banana flour

Cassava (Manihot esculenta Crantz) is a crucial crop in tropics and subtropics, primarily cultivated for its tuber. However, its foliage is rich in protein and can supply essential elements for ruminants. The objective of this study was to evaluate the phytochemical compounds by Gas chromatography-MS (GC-MS) and the main phenolic by High Pressure Liquid Chromatography (HPLC) present in cassava foliage, along with the fermentation pattern using a semi-automated gas production (GP) system. The in vitro evaluation was carried out for four diets formulated as follows: T1 (alfalfa: grass hay at ratio of 30: 70); T2 (alfalfa: grass hay: banana flour 30:60:10); T3 and T4 (replaced alfalfa in T1 and T2 with cassava foliage, respectively). The addition of green banana flour aimed to increase the diets’ energy. The GC-MS results indicated that cassava foliage showed a large number of valuable bioactive components, with the biflavonoid isoginkgetin representing the major component at 25.33% of total peak area percentage. The HPLC analysis declared that rutin, gallic acid, and ferulic acid were the main phenolic compounds presented in cassava foliage ethanolic extract. The accumulative gas after 24 h of incubation was significantly lower with cassava diets compared to alfalfa diets, being 119.3 versus 130.1 ml/g DM, respectively. The degradation of both organic matter and neutral detergent fiber was significantly higher with alfalfa compared to cassava diets, while there was no significant difference between alfalfa and cassava diets on final pH, ammonia concentration and protozoal count. Banana flour inclusion, regardless of the forage type, decreased the accumulative gas after 24 h of incubation with about 9% compared with no banana addition. The use of cassava foliage in ruminant diets considered a promising protein source with valuable bioactive components that could have a positive effect on animal health and production.

Experimental measurements, thermodynamic modeling and molecular dynamics simulation of the multiphase equilibria of {1-butanol + n-butyl acetate + [EMIM][EtSO4]} systems at 101.3 kPa

Ionic liquids (ILs) are organic salts with normal melting temperatures lower than 373 K and have interesting properties to be used as environment-friendly solvents, as low volatility, high thermal stability, and easy containing and recycling ability. Besides, they are versatile molecules whose anions and cations can be changed to solubilize different organic compounds. For these reasons, ionic liquids can be used in many industrial applications, such as in separation processes as azeotropic distillation and liquid–liquid extraction, and, because of that, it is important to know the phase equilibrium behavior for equipment design for these processes. However, experimental data for systems containing ionic liquids are very scarce. This work aimed to analyze the fluid phase behavior of the 1-butanol + n-butyl acetate + [EMIM][EtSO4] system in liquid–liquid (LLE), vapor–liquid (VLE) and vapor–liquid–liquid equilibria (VLLE) at 101.3 kPa. LLE was analyzed in glass-jacketed vessels and VLE and VLLE were analyzed in a modified Othmer ebuliometer. Compositions of each phase sample were obtained from calibration curves with built-in functions of the refractive index and density. Experimental data were submitted to thermodynamic consistency tests and the consistent points were modeled with the Group Contribution Volume Translated Peng-Robinson (GC-VT-PR) and Non-Random Two-Liquid (NRTL) models. Vapor pressure and saturated liquid density data for the ionic liquid, necessary for the determination of the pure component parameters, were obtained from analytical methods. For the LLE, a phase stability test was also done to evaluate the data consistency by the Gibbs energy of the mixing surface and to determine the plait point. Molecular dynamics (MD) simulations, performed by NAMD software, were also conducted to understand the behavior of the multiphase fluid equilibria, by analyzing the structural properties of the components. Results of the thermodynamic modeling in terms of the deviations of temperature and mole fractions showed that these models were adequate to study the phase behavior of systems containing ionic liquids, while the dynamic simulations suggested that the ionic liquid molecules strongly interact with 1-butanol molecules when compared with the n-butyl acetate molecules.

Simultaneous Detection of a wide range of synthetic and natural dyes in artworks using UHPLC-PDA-HRMS

This paper presents a validated method using ultra-high pressure liquid chromatography with photodiode array detection N coupled to high-resolution mass spectrometry (UHPLC-PDA-HRMS) for the simultaneous analysis of a wide range of natural and synthetic organic colourants, including neutral, acid and basic dyes. In total, 30 natural and 62 synthetic organic dye reference samples (which contain118 compounds because some of the dyes are composed of mixtures) were analysed. The method demonstrated good linearity for the 12 dyes selected for method validation achieving correlation coefficients (R2) exceeding 0.99 for both PDA and MS detectors. Detection limits (LOD) varied from 0.23 ppm (Crystal violet) to 4.12 ppm (Amido naphthol red G) based on the UHPLC-PDA signal, and from 0.024 ppm (Diamond green G) to 0.65 ppm (Cochineal red A) based on the UHPLC-MS signal. Precision, measured by intra-day relative standard deviation (RSD) values was consistently under 5% for UHPLC-PDA and under 9% for UHPLC-MS, while inter-day RSD values were below 13% for UHPLC-PDA and below 8% for UHPLC-MS. The method's applicability was further tested on two historical artworks: a tapestry by Lanckaert (1587-1589) from the collection of the Museum De Lakenhal, Leiden, The Netherlands, and a 19th-century hip cloth from Aceh, Indonesia. Results from the case studies underscore the method's effectiveness in identifying complex mixtures of both synthetic and natural organic colourants in a single run using minute sample sizes. Beyond offering critical insights into historical dyeing procedures that support conservation work, the method also enhances understanding of technological advancements in textile production.

Phytochemical Compositions and Antioxidant Activities of Different Cultivars of Prunus salicina Lindl. in Southern China.

There are representative Prunus salicina Lindl. (plum) cultivars in the different provinces of Southern China. However, little data are available on the physiochemical characteristics of those plums. In this study, the fruit weight and size, edible rate, rate of juice, color, moisture, total soluble solids, total acids, ascorbic acid (AA), reducing sugar, polysaccharide, total polyphenols, total tannins, total anthocyanins, antioxidant activity, and phenolic composition of 11 plum varieties in Southern China were analyzed. The results showed that the content of reducing sugar, AA, polysaccharide, total polyphenols, total tannins, and total anthocyanins in different cultivars was in the range of 3.09-10.48g/100g, 2.30-14.75mg/100g dry weight (DW), 0.78-2.20g/100g, 20.73-41.18mg/g DW, 0.42-1.09mg/g DW, and 1.80-8.95mg/g DW, respectively. A total of 11 phenolic compounds were identified in plums by ultra high pressure liquid chromatography (UPLC)-QqQ-MS/MS. Cultivar "Da Pao" showed the highest level of total polyphenols, and ferric ion reducing antioxidant power values, whereas cultivar "San Hua" had the highest content of total anthocyanins, 1,1-diphenyl-2-picrylhydrazyl, and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt values. Principal component analysis separated cultivars according to their physiochemical characteristics. This study provides reference information for consumers and the further deep processing of those plums.

Prediction of Liquid Film Thickness and Pressure Gradient of Swirling Annular Flows in Vertical Pipes Based on One-Dimensional Three-Fluid Model

Prediction of Liquid Film Thickness and Pressure Gradient of Swirling Annular Flows in Vertical Pipes Based on One-Dimensional Three-Fluid Model

Microfluidic Monodispersed Microbubble Generation for Production of Cavitation Nuclei.

Microbubbles, acting as cavitation nuclei, undergo cycles of expansion, contraction, and collapse. This collapse generates shockwaves, alters local shear forces, and increases local temperature. Cavitation causes severe changes in pressure and temperature, resulting in surface erosion. Shockwaves strip material from surfaces, forming pits and cracks. Prolonged cavitation reduces the mechanical strength and fatigue life of materials, potentially leading to failure. Controlling bubble size and generating monodispersed bubbles is crucial for accurately modeling cavitation phenomena. In this work, we generate monodispersed microbubbles with controllable size using a novel and low-cost microfluidic method. We created an innovative T-junction structure that controls the two-phase flow for tiny, monodispersed bubble generation. Monodisperse microbubbles with diameters below one-fifth of the channel width (W = 100 µm) are produced due to the controlled pressure gradient. This microstructure, fabricated by a CNC milling technique, produces 20 μm bubbles without requiring high-resolution equipment and cleanroom environments. Bubble size is controlled with gas and liquid pressure ratio and microgeometry. This microbubble generation method provides a controllable and reproducible way for cavitation research.

A computational study on the sensitivity of slip constraints in the blade coating process of an electrically conducting oldroyd 4-constant fluid

The blade coating process holds significant importance due to its widespread application in manufacturing products such as newspapers, photographic film, fibers, catalogs, and magnetic storage media. Its economic impact has driven extensive research aimed at deepening the understanding of the underlying physical mechanisms, ultimately leading to improvements in process efficiency and optimization. Therefore, this article investigates the blade coating process of an electrically conducting Oldroyd 4-constant liquid with velocity slippage on the blade surface. The impression of viscous dissipation is also inspected through the energy equation. The mathematical equations are modeled with the use of lubrication approximation theory and the normalized equations of the Oldroyd 4-constant fluid and are numerically solved by the shooting method. To offer valuable insights, the pressure, pressure gradient, velocity, temperature, and load metrics are calculated and displayed in graphs and tables. It is found that liquid velocity and pressure decrease as the Hartmann number increases. As the Brinkman number increases, the temperature distribution increases, with the peak temperature appearing in the narrowest region of the flow.

Poplar Leaf Bud Resin Metabolomics: Seasonal Profiling of Leaf Bud Chemistry in Populus trichocarpa Provides Insight Into Resin Biosynthesis.

Trees in the genus Populus synthesize sticky and fragrant resins to protect dormant leaf buds during winter. These resins contain diverse phenolic metabolites, in particular hydroxycinnamate esters and methylated flavonoids. P. trichocarpa leaf bud resin is characterized by methylated dihydrochalcone aglycones. To determine how the resin profile is influenced by seasonal changes, P. trichocarpa lateral leaf bud extracts and secreted surface resin were collected monthly over a one-year cycle. The dihydrochalcones in both sets of extracts were quantified using ultrahigh pressure liquid chromatography - mass spectrometry (UPLC-MS) and other chemical changes monitored using non-targeted metabolomics by ultrahigh pressure liquid chromatography - high resolution mass spectrometry (UPLC-HRMS). The results indicate that the dihydrochalcone content changes over the seasons and that biosynthesis occurs concomitant with bud development in the summer months. Non-targeted metabolomics data confirmed a pattern of dramatic changes in the summer, and further suggested additional periods of substantive biochemical change in the resin. While overall patterns of surface-extracted resin matched that of whole bud extracts, some of the dynamics were shifted in the surface resin samples. This study provides the basis for the use of dihydrochalcones and other identified resin components as metabolic markers for more detailed investigations of resin biosynthesis, secretion and movement to the bud surface.

Does pre-existing differential pressure have an impact on poroelastic compressibilities?

The existing formulation of quasistatic poroelasticity for saturated porous materials relies on the assumption that differential pressure, defined to be the difference between the confining and liquid pressures, is zero at the reference state. This as- sumption can be problematic in problems involving swelling media, such as clay, and deep underground where pre-existing pore pressure may differ from the total pressure. Here, the quasistatic poroelastic equations are derived from only the conservation of mass for each phase and the Terzaghi effective stress principle for the case when there is a nonzero reference differential pressure. In the process, a dynamic equation for the porosity is derived, and one additional parameter representing a dimensionless reference differential pressure is introduced. Although the form of the quasistatic poroelastic equations remains the same, the poroelastic compressibilities change with the reference state’s nonzero differential pressure. The changes to these compressibil- ities are systematically outlined, and the impact on more specific classes of material are examined. The altered compressibilities imply, among other changes, that the compressional velocity is a function of the pre-existing differential pressure, which is useful to account for in dynamic measurements, but that the dependence is weak for materials with low compressibilities.

Liquid, liquid crystal, and crystal states of different shaped colloids in nonuniform fields via osmotic force balance.

We report a model to predict equilibrium density profiles for different shaped colloids in two-dimensional liquid, nematic, and crystal states in nonuniform external fields. The model predictions are validated against Monte Carlo simulations and optical microscopy experiments for circular, square, elliptical, and rectangular colloidal particles in AC electric fields between parallel electrodes. The model to predict the densities of all states of different shaped particles is based on a balance of the local quasi-2D osmotic pressure against a compressive force due to induced dipole-field interactions. The osmotic force balance employs equations of state for hard ellipse liquid, nematic, and crystal state osmotic pressures, which are extended to additional particle shapes. The resulting simple analytical model is shown to accurately predict particle densities within liquid, liquid crystal, and crystal states for a broad range of particle shapes, system sizes, and field conditions. These findings provide a basis for quantitative design and control of fields to assemble and reconfigure colloidal particles in interfacial materials and devices.

ҚАТТЫ ЦЕНТРІ БАР ДӨҢГЕЛЕК ОСЬТІК СИММЕТРИЯЛЫҚ МЕМБРАНАНЫҢ ФИЗИКАЛЫҚ ЖӘНЕ ГЕОМЕТРИЯЛЫҚ ПАРАМЕТРЛЕРІН ОҢТАЙЛАНДЫРУ

The mathematical model of an isotropic circular plate-membrane with a non-deformable fixed central disk loaded by a uniformly distributed static load is considered in a linear formulation. On this basis, the extreme problem of determining the rational physical and geometrical characteristics of an elastic element from the condition of the maximum of the target function of the thrust (permutation) force with two coupling equations in the form of the classical Huber-Genke-Mises strength hypothesis and a geometrical relation limiting the membrane thickness in accordance with the known fundamental Kirchhoff assumptions of the technical theory of small plate bending is solved. To illustrate the proposed algorithm and calculation procedure, a numerical example of the selection of optimum parameters of a manganese steel diaphragm with given dimensions of thickness and outer radius is presented. The results of the work can be used in the process of designing high-precision membrane-type pressure gauges, widely used in mechanical engineering, aviation, instrumentation, and construction in the design of pressure tanks with controlled excess pressure of gas or liquid.

Analysis of the Current Situation of Liquidity Risk Management in China's Commercial Banks and the Proposed Countermeasures

This paper discusses in depth the importance of liquidity risk management in commercial banks and the challenges it faces at a time of accelerated global economic integration. Financial globalization not only brings unprecedented development opportunities for the banking industry, but also exposes it to more complex and volatile liquidity risks. As an important part of the financial system, the sound operation of commercial banks is crucial for maintaining financial stability and healthy economic development. The article focuses on the current situation of liquidity risk management in Chinese commercial banks and reveals the core issues of weakening deposit base and loan expansion aggravating liquidity pressure through detailed analysis. Subsequently, a combination of literature review and case studies is used to analyze the dual impact of macroeconomic fluctuations and micro-management deficiencies on liquidity risk. Ultimately, the study concludes by emphasizing the key roles of the improvement of the government regulatory system and fintech in optimizing the asset and liability structure of banks and enhancing the efficacy of risk management, which together safeguard the sound operation of the financial system and the sustained and healthy development of the economy.

Analysis of the Coupling Mechanism of Liquid Cylinder Vibration Based on the Low-Speed Operating Conditions of Neural Network Model

The connection between the friction negative and related damping is on the low-speed hydraulic cylinder, which will generate the vibration and influence of the hydraulic cylinder, which inhibits the accuracy of the hydraulic equipment. In order to effectively solve this problem, this paper creates a neural network model, considering the negative damping and related damping effects under low-speed conditions, and intended the coupling mechanism of negative damping and related damping. Based on the converter of the hydraulic cylinder, the nonlinear stiffness characteristics of the sensor hydraulic cylinder were analyzed, and the requirements of the hydraulic cylinder collection were obtained according to the requirements of the energy star collection of the liquid voltage star, and the equivalent of the sensor liquid pressure cylinder was obtained. At the same time, the sensor system implements feedback control on vibration velocity and displacement based on changes in piston position, in order to analyze the coupling mechanism of hydraulic cylinder vibration under low-speed operating conditions. The results of the study show that the function of the feedback controller is systematic, and the antipity control contains the possibility of minimizing serious damage and can effectively improve the efficiency and stability of the system. In the actual manufacturing process, we studied the vibration coupling effect of the liquid cylinder under low-speed conditions, proved the change characteristics of the vibration amplitude and frequency of the hydraulic cylinder, and revealed the related damping in the vibration.

Simplified Approach to Evaluate Cavitation Intensity Based on Time Information on Imposed Pressure in Liquid

Cavitation damage is an important research topic in fluid–structure interactions, such as those being studied using the mercury target for the pulsed neutron source at the Materials Life Science Experimental Facility/Japan Proton Accelerator Complex. Hence, the estimation of cavitation damage (cavitation intensity) is required from the perspective of structural integrity. The results of previous studies suggest that the maximum radii of cavitation bubbles immediately prior to collapse are related to cavitation intensity. Therefore, we propose a method for estimating the maximum radius from the time information by measuring the vibrations of structure walls that are induced by collapsing cavitation bubbles in a confined liquid. In this study, we used a magnetic impact testing machine to experimentally investigate the cavitation bubble dynamics, directly observe the bubble collapsing behavior, and measure the induced vibration. We experimentally confirmed that the time information is useful in the estimation of the maximum radii of bubbles. Moreover, we theoretically derived a simple evaluation formula to estimate the maximum radius from the time responses of the imposed pressure in a confined liquid in a structure.

Effect of stretching ratio on the structure and enactment of porous PVDF-HFP hollow fiber membranes for CO2 absorption

Carbon dioxide (CO2) is responsible for increment of the Earth surface temperature and the subsequent environmental issues. In this regard, membrane contactor is one of the emerging technologies that can be applied for controlling CO2 emission. More specifically, the intrinsic structure of membrane plays an important role to govern the performance of CO2 absorption. In this study, considering stretching ratio (SR) as a key factor to affect membrane structural properties, highly porous poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) hollow fiber membranes were fabricated by a non-solvent induced phase separation method. The results showed that the membrane dimension and thickness were significantly reduced by optimizing the SR. The optimum membrane structure was found at SR of 1.5 where the mean pore size, CO2 permeance, collapsing pressure and liquid entry pressure of 0.032 μm, 3440 GPU, 550 kPa and 500 kPa were achieved, respectively. The prepared membranes showed open structure with overall porosity of more than 80%. The upgraded membrane at SR of 1.5 presented the maximum CO2 absorption flux of 9.8 × 10− 4 mol/m2 s and the minimum mass transfer resistance of 49,544 (m/s)−1. Furthermore, a stable CO2 absorption performance was achieved during 80 h continuous operation with a flux decline of only about 9%. The findings of this work demonstrated that by applying a cost-effective fabrication method, we can potentially enhance the PVDF-HFP membrane properties for CO2 adsorption without requiring an additional post-modification step.

Assessing the potential spray drift of a six-rotor unmanned aerial vehicle sprayer using a test bench and airborne drift collectors under low wind velocities: impact of atomization characteristics and application parameters.

The unmanned aerial spraying systems (UASS) have gained widespread use for plant protection in recent years. However, spray drift from UASS is a major concern when controlling weeds over large areas and warrants a thorough investigation. This study examined the atomization characteristics of the herbicide florpyrauxifen-benzyl under downwash airflow using a UASS spray test platform. Potential spray drift was assessed using a test bench (TB) and airborne drift collectors (ADCs) in the field under low wind speeds (<1 m s-1). Atomization characteristics were significantly affected by the spray liquid, adjuvant, nozzle type and spray pressure. The addition of an adjuvant reduced the liquid sheet length, improved physicochemical properties and increased droplet size under the downwash airflow field. Drift evaluation in the field using the TB revealed that sediment spray drift predominantly occurred from the middle to the entire length of the device when fine-to-medium droplets were produced after the sprayer passed. ADC assessment found that higher flight altitudes and finer droplets resulted in higher drift values, whereas the addition of an adjuvant and the use of an air-induction nozzle reduced drift <3 m aboveground. The combination of using TB in the target area and ADCs in the off-target area as an alternative method to determine residual droplets in the current airflow provided valuable insights into airborne drift assessment for UASS. © 2024 Society of Chemical Industry.