Viscosity Measurements Research Articles

New empirical correlations for the viscosity of selected organic phase change materials

Although there are many methods and instruments for measuring viscosity, it is still difficult to determine a reliable value of the dynamic viscosity of complex chemicals such as paraffins and fatty acids. This is due to the complex and heterogeneous structure of these compounds in the case of commercial products. On the other hand, the measuring instrument should be selected very carefully, including its measuring principle and measuring range. This paper presents results of viscosity measurements of three organic PCMs (phase change materials) obtained in four different research institutions. Commercial products: paraffin, myristic acid (97%) and mixture of palmitic acid (55%) and stearic acid (45%) were selected as PCMs. Four different viscometers, namely Fungilab V-Pad, Rheotest LK 2.2, Rheometer Anton Paar MCR 102, and Brookfield DV-II + Pro have been used to determine temperature dependent dynamic viscosity of the tested PCMs. Using a large database of present measurement results, correlations were developed to calculate the dynamic viscosity of fatty acids and paraffins, which predict the experimental data within a band of ±20%.

Effect of tertiary processing on physical, optical, phytochemical as well as rheological properties of high-protein rice.

The first high-protein rice variety of India, CR Dhan 310, developed at ICAR-NRRI, Cuttack is being selected for the study. It contains 10.1% protein in milled rice as compared to 6-7% protein content in the milled rice of any other normal variety. It has intermediate amylose content (25.1%), medium bold grains rich in protein (10.1%) The significant changes in properties of raw and parboiled rice on processing were studied at statistical differences of p ≤ 0.05. These properties included physical, optical, antioxidant and rheological properties which changed with different processing techniques. All the three processes namely, puffing, popping and flaking increased the dimensions as compared to the raw rice. Peak viscosity measurements demonstrated the breakdown of starch molecules, with white rice having the greatest value (4145 cP) and popped rice having the lowest value (2017 cP) as a result of the starch granules being gelatinized during the production of popped rice. Highest anthocyanin content (2.93 mg/100 g) was observed in puffed rice, phenolic content (347.93 mg/100 g) was highest in popped rice and flaked/flattened rice showed highest flavonoid content (127.12 mg/100 g) indicating that tertiary processing of rice obtained higher values of phytochemicals when compared to the plain high-protein rice. This indicates that the processed products of rice can be consumed directly as ready-to-eat or can be used in preparation of other functional foods to combat malnutrition and build nutritional security. The study indicates that processing could improve the nutritional quality of the rice products.

Optical knife-edge detection for micropillar-based microfluidic viscometer

We demonstrate the use of an optical knife-edge technique in micropillar-based microfluidic chips, which are intended for viscosity measurements. Our demonstrations rely on the use of a single photodiode, offering a significant cost, form factor and computational efficiency advantage over CMOS camera detection. Our readout methodology involves the utilization of pillars as waveguides, such that a laser is coupled from the backside of the fluidic chip, while the output light is monitored with a photodiode using knife-edge detection. The bending of the pillars due to applied flow alters the observed light intensity, from which the bending angle could be deduced. We present ray-tracing simulations and conduct proof-of-concept experiments on a micropillar-based microfluidic chip. The bending of the pillar observed with the knife-edge technique matches well with that observed with a camera. With further development, the proposed methodology can be employed as a compact and low-cost point-of-care instrument for real-time viscosity measurements.

Predicting nonradiative decay barrier of BODIPY dye in polar environment by applying ONIOM multiscale method

Fluorescent molecular sensors are widely used in biological research. They allow straightforward viscosity, temperature or polarity measurements at the microscopic level, including live cells. Maps of desired physical properties can be obtained by applying fluorescence lifetime imaging microscopy (FLIM) to cells. One of the most important properties of a cell is viscosity, as it affects other parameters, such as the rate of biochemical reactions and particle diffusion. Boron-dipyrromethene (BODIPY) compounds are widely used for viscosity measurements, but current variants have the undesirable sensitivity to polarity, and more suitable alternatives are being sought using theoretical computations. The polarizable continuum model (PCM) used in previous studies did not adequately take into account the influence of the polar environment when calculating the BODIPY activation energy associated with polarity sensitivity. After applying the multilayer ONIOM method in polar and non-polar environments, the calculated maximum wavelengths of the fluorescence spectra of the 8PhBODIPY compound were closer to the experimental results compared to PCM. The activation energy was also calculated, its value in polar and non-polar environments qualitatively corresponded to the experimental results, and the quantitative agreement was reached using the empirical correction.

Synthesis of Novel [{(2-Amino-5-Nitro-N-[(E)-Thiophen-2-yl-Methylidene]Aniline-κ3N1:N4:S)(Sulphato-κ2O1:O3)}Zinc(II)] Complex with Physico-Chemical and Biological Perspective Exploration: A Combined Experimental and Computational Studies.

A novel metal complex was synthesized using freshly prepared 2-Amino-5-nitro-N-[(E)-thiophen-2-yl-methylidene]aniline ligand with Zn (II) sulphate heptahydrate in a 1:1 molar ratio. The ligand and the complex were characterized using different spectroscopic techniques, and the complex was assigned a distorted square pyramidal geometry. Additionally, DNA binding assays and antibacterial activity were used to assess the biological perspectives for the synthesized complex, including the ligand and complex which was further confirmed by molecular docking. Fluorescence Spectroscopy, viscosity measurement, and adsorption measurement were used to investigate the interaction of the Zn (II) complex with CT-DNA. A comparativein vitroantibacterial activity study againstEscherichia coli, Klebsiella pneumoniae,Bacillus subtilis,andStaphylococcus aureusstrains were studied with free ligand and Zn (II) metal complex. The stable geometry of the complex was additionally established through computational simulation utilizing density functional theory, which was followed by the calculation of several electronic properties. The ADMET characteristics of the complex and ligand were also assessed using ADMET analysis. The in-silico ADMET properties pointed to a significant drug-likeness feature in the synthesized compounds, based on the Lipinski criteria.

Evaluation of the Stability of Newborn Hospital Parenteral Nutrition Solutions.

(1) Background: parenteral nutrition (PN) solutions are an extremely complex mixture. It is composed of a multitude of chemical elements that can give rise to a large number of interactions that condition its stability and safety. The aim of this study was to evaluate the stability of PN solutions for preterm infants. (2) Methods: eight samples were prepared according to the protocol for prescribing PN in preterm infants. Samples PN1-PN7 had the normal progression of macronutrients and standard amounts of micronutrients for a 1 kg preterm infant. The PN8 sample had a high concentration of electrolytes, with the idea of forcing stability limits. Samples were stored both at room temperature and under refrigeration. Measurements of globule size, pH, density, and viscosity were performed in both storage protocols on different days after processing. (3) Results: the changes in the composition of the samples did not affect the evolution of the stability at the different measurement times and temperatures. Viscosity was affected by the compositional changes made in the PN samples, but no alterations due to time or temperature were observed. Density and pH remained stable, without significant changes due to time, storage temperature, or different composition. (4) Conclusion: all samples remained stable during the study period and did not undergo significant alterations due to compositional changes or different experimental conditions.

Electrospun PLLA/PEI nanofibers for controlled drug release behaviors and antibacterial efficiency

This study focused on the poly(L-lactic acid) (PLLA) polymer matrices by adding branched polyethyleneimine (PEI) as an aminolysis agent. Electrospun nanofibers were made by blending PLLA and PEI at various weight ratios (85-15, 75-15, and 65-35) and mixing times (0.5 h, 1 h, and 2 h). Amine groups were introduced into the nanofiber matrices, as confirmed by Fourier-transform infrared (FTIR) spectroscopy. The PLLA-PEI reaction was affected by mixing time, as shown by rheological measurements of absolute viscosity and surface tension. As a result, the nanofiber diameters decreased up to 42% and 89% with longer mixing time and higher PEI content, respectively. The aminolysis reaction rate increased up to 6.6 times with more PEI. Furthermore, the nanofibers had improved host-guest interactions, as demonstrated by contact angle, drug release, dye adsorption and water adsorption tests. The drug-loading capacity of the nanofibers was enhanced by PEI modification, as indicated by the release profile of tetracycline hydrochloride. The nanofibers also revealed more than 99.99% antibacterial activity due to the presence of the amine groups in PEI. Optimum mixing time and polymer ratio were proved to be substantial parameters to reach appropriate nanofiber and improve spinnability for further biomedical applications.

Fluorescent Probe for Investigating the Mitochondrial Viscosity and Hydrogen Peroxide Changes in Cerebral Ischemia/Reperfusion Injury.

Cerebral ischemia-reperfusion injury (CIRI), a cause of cerebral dysfunction during cerebral infarction treatment, is closely associated with mitochondrial viscosity and hydrogen peroxide (H2O2). However, the accurate measurement of mitochondrial viscosity and H2O2 levels in CIRI is challenging because of the lack of sufficient selectivity and blood-brain barrier (BBB) penetration of existing monitoring tools related to CIRI, hampering the exploration of the role of mitochondrial viscosity and H2O2 in CIRI. To address this issue, we designed an activatable fluorescent probe, mitochondria-targeting styryl-quinolin-ium (Mito-IQS), with excellent properties including high selectivity, mitochondrial targeting, and BBB penetration, for the visualization of mitochondrial viscosity and H2O2 in the brain. Based on the real-time monitoring capabilities of the probe, bursts of mitochondrial viscosity and H2O2 levels were visualized during CIRI. This probe can be used to monitor the therapeutic effects of butylphthalein treatment. More importantly, in vivo experiments further confirmed that CIRI was closely associated with the mitochondrial viscosity and H2O2 levels. This discovery provides new insights and tools for the study of CIRI and is expected to accelerate the process of CIRI diagnosis, treatment, and drug design.

Effects of liquid-to-solid ratio and gamma irradiation on the rheology and cytocompatibility of a beta-tricalcium phosphate-based injectable bone substitute

Injectable bone substitute (IBS) materials are commonly used to fill irregular-shaped bone voids in non-load-bearing areas and can offer greater utility over those which are in prefabricated powder, granule, or block forms. This work investigates the impact of liquid-to-solid ratio (LSR) on the rheology and cytocompatibility of IBSs formulated from bioactive glass particles and β-tricalcium phosphate (β-TCP) in glycerol and poly(ethylene glycol) (PEG). IBS formulations of varying LSR were prepared and packed in 3 cc open-bore syringes and sterilized via gamma irradiation (10 kGy, 25 kGy). Gamma-irradiated formulations with high PEG content required the highest (73 N) mechanical force for injection from syringes. Oscillatory viscosity measurements revealed that the viscosity of samples was directly proportional to glycerol content. PEG and glycerol displayed competing effects on the washout resistance and cohesiveness of samples, which were based on total weight loss in media and Ca2+ ion release, respectively. Cell viability in 24-h extracts of 10 kGy gamma-sterilized and 25 kGy gamma-irradiated samples were 22.94% and 56.53%, respectively. The research highlights the complex interplay of IBS components on IBS rheology and, moreover, the cytotoxicity behaviors of beta-tricalcium phosphate-based injectable bone substitutes by in vitro experiments.

New Viscometers for Measuring the Viscosity of Liquids

This article’s goal is to present a viscometer that makes use of a novel viscometry measurement technique. The post will also suggest brand-new vibration viscometers. The development of new viscometers has allowed for the continuous and instantaneous measurement of liquid viscosity. The viscosity can be precisely measured automatically using these viscometers, which are made for industrial application. These viscosity measurement tools can currently be applied to a number of different tasks, including the research of recently developed oil products, the choice of the best flow characteristics for different transfer situations, and the advancement and refinement of fuel preparation techniques.

A PEGylated PVDF Antifouling Membrane Prepared by Grafting of Methoxypolyethylene Glycol Acrylate in Gama-Irradiated Homogeneous Solution.

In this study, methoxypolyethylene glycol acrylate (mPEGA) served as a PEGylated monomer and was grafted onto polyvinylidene fluoride (PVDF) through homogeneous solution gamma irradiation. The grafting process was confirmed using several techniques, including infrared spectroscopy (FTIR), thermodynamic stability assessments, and rotational viscosity measurements. The degree of grafting (DG) was determined via the gravimetric method. By varying the monomer concentration, a range of DGs was achieved in the PVDF-g-mPEGA copolymers. Investigations into water contact angles and scanning electron microscopy (SEM) images indicated a direct correlation between increased hydrophilicity, membrane porosity, and higher DG levels in the PVDF-g-mPEGA membrane. Filtration tests demonstrated that enhanced DGs resulted in more permeable PVDF-g-mPEGA membranes, eliminating the need for pore-forming agents. Antifouling tests revealed that membranes with a lower DG maintained a high flux recovery rate, indicating that the innate properties of PVDF could be largely preserved.

Effect of starting materials’ dispersion on the properties of AlN powder synthesized by carbothermal reduction and nitridation

This study examined the effects of starting material dispersion on the formation of AlN powder synthesized by carbothermal reduction-nitridation (CRN) route. After preparing aqueous and non-aqueous slurries containing 6.5 vol % of Al2O3 and carbon black powder with/without a dispersant, the particle dispersion was evaluated by sedimentation and viscosity measurements. The zeta potential was also measured to determine the optimal dispersion conditions for electrostatic repulsion because carbon black is challenging to disperse in water, owing to its low surface charge and poor wettability. The aqueous slurry prepared with 5 wt % Gen0451 dispersant at pH = 10 showed the highest degree of dispersion. Complete AlN conversion was achieved by nitridation at 1600 °C for 6 h under 10 L/min N2 flow. This result clearly showed the importance of starting material dispersion on the synthesis of AlN by CRN, demonstrating the feasibility of aqueous processing instead of conventional solvent-based processing.

1‐Benzyl‐1H‐indazol‐3‐ol Copper(II) Derivatives as Anticancer Agents: In‐vitro Interaction with DNA/BSA, DFT, Molecular Docking and Cytotoxicity on MCF7 Cells

AbstractA set of three copper(II) complexes C28H24CuN4O2 [CuL1], C24H22CuN4O [CuL2] and C26H22CuN4O [CuL3] incorporated with ligands 1‐benzyl‐1H‐indazol‐3‐ol, 2,2′‐bipyridyl and 1,10‐phenanthroline have been synthesized, characterized and subjected for biomedical applications. New copper(II) derivatives were characterized by FTIR, EPR and HRMS spectral tools. Cyclic voltammograms were recorded to ascertain redox potential and UV‐Vis and Fluorometer were employed to establish photophysical properties of all the new copper(II) complexes. Further, these derivatives of Cu(II) were subjected for DNA and BSA binding studies by using absorption‐emission spectral methods and viscosity measurements as well as by molecular docking. DFT studies of the above‐mentioned derivatives suggested square planar geometry along with other relevant molecular investigations. Eventually, these new Cu(II) complexes have been tested with DPPH and MTT assay to determine the cytotoxicity against MCF7 cell lines to observe remarkable potency with IC50 values 80.68 μg/ml, 49.40 μg/ml and 45.91 μg/ml, respectively.

Optimization and degradation studies of cellulose transesterification to palmitate esters in superbase ionic liquid

Cellulose palmitates (CPs) were synthesized with varying degrees of substitution (DS) via a catalyst-free, homogeneous transesterification of cellulose in a novel superbase ionic liquid (SB-IL) system, specifically 5-methyl-1,5,7-triaza-bicyclo[4.3.0]non-6-enium acetate [mTBNH][OAc], combined with dimethyl sulfoxide (DMSO) as a co-solvent, using vinyl palmitate as the acylating agent. We examined the influence of reaction temperature, reaction time, and the molar ratio of vinyl palmitate to anhydroglucose unit (AGU) on the DS, which ranged from 0.5 to 2.3 under the given conditions. Notably, the reaction order of the three hydroxy groups was C6–OH > C2–OH > C3–OH. To elucidate the chemical structure of CPs and confirm the transesterification process, various spectroscopic techniques including 1H nuclear magnetic resonance (NMR), 13C NMR, heteronuclear single quantum correlation (HSQC), and solid-state NMR were employed. Higher reaction temperatures and extended reaction times led to a decrease in the DS of CPs, potentially due to the degradation of some of the involved chemicals during the transesterification process. We also investigated the stability of the pure ionic liquid (IL) and the IL + DMSO solvent system at elevated temperatures by heating them at 100 °C for 5 h, confirming their chemical integrity through 1H NMR analysis. Additionally, we assessed the compatibility between the solvent system and cellulose by subjecting a mixture of cellulose and the solvent system to 100 °C for 5 h. To compare the structures of untreated cellulose and regenerated cellulose, Fourier transform infrared (FT-IR) spectroscopy was employed. Furthermore, we determined the molar mass of both untreated cellulose and regenerated cellulose, as well as CPs synthesized at higher reaction temperatures and longer durations, using intrinsic viscosity measurements. Lastly, we examined the solubility properties of CPs.

Switchable Redox and Thermo-Responsive Supramolecular Polymers Based on Cyclodextrin-Polyoxometalate Tandem.

Supramolecular polymers built from stimuli-responsive host-guest interactions represent an attractive way of tailoring smart materials. Herein, we exploit the chaotropic effect of polyoxometalates and related host-guest properties to design unconventional polymer systems with reversible redox and thermo-responsive sol-gel transition. These supramolecular networks result from the association of cyclodextrin-based oligomers and Keggin-type POMs acting as electro-active crosslinking agents. The structure and the dynamics of such self-assembly systems have been investigated using a multiscale approach involving MALDI-TOF, viscosity measurements, cyclic voltammetry, 1H-NMR (1D and DOSY), and Small-Angle X-ray Scattering. Our results reveal that the chaotropic effect corresponds to a powerful and efficient force that can be used to induce responsiveness in hybrid supramolecular oligomeric systems.

Hyperstretching in elongational flow of densely grafted comb and branch-on-branch model polystyrenes

Strain hardening of long-chain branched polymers in elongational flow occurs due to the stretch of the backbone chain between branch points. With an increasing number of side arms, the length of the backbone chain segment between two branch points of a comb decreases. Of particular interest is the case when the number Nb of arms per entanglement length of the polymer is larger than one. This leads not only to larger strain hardening but also to hyperstretching, i.e., the elongational stress growth shows an enhanced increase with strain. We consider elongational data reported by Abbasi et al. [Macromolecules 50(15), 5964–5977 (2017)] and Faust et al. [Macromol. Chem. Phys. 224(1), 2200214 (2023)] on a series of comb and branch-on-branch polystyrene (PS) melts with the average number Nb of branches per entanglement segment of the backbone ranging from Nb = 0.2 to Nb = 9.5. In addition, we present measurements of the elongational viscosity of two PS combs with Nb = 4.7 as well as of blends consisting of 5 to 50 wt. % of a PS comb and a monodisperse linear PS. Analysis by the hierarchical multimode molecular stress function model shows that while backbone chains of loosely grafted combs with Nb < 1 are stretched affinely in elongational flow, backbone chains of more densely grafted combs with Nb > 1 show increasing hyperstretching with increasing Nb. The elongational data of the comb/linear blends confirm that hyperstretching is an intrinsic property of the comb macromolecule with Nb > 1, independent of its concentration in the blend. While this is of considerable interest from a modeling point of view, hyperstretching causing an enhanced increase of the elongational stress growth can also have a significant impact on the processability of polymers, and quantification of this effect is, therefore, important.

Enhancing Mucoadhesive Properties of Gelatin through Chemical Modification with Unsaturated Anhydrides.

Gelatin is a water-soluble natural polyampholyte with poor mucoadhesive properties. It has traditionally been used as a major ingredient in many pharmaceuticals, including soft and hard capsules, suppositories, tissue engineering, and regenerative medicine. The mucoadhesive properties of gelatin can be improved by modifying it through conjugation with specific adhesive unsaturated groups. In this study, gelatin was modified by reacting with crotonic, itaconic, and methacrylic anhydrides in varying molar ratios to yield crotonoylated-, itaconoylated-, and methacryloylated gelatins (abbreviated as Gel-CA, Gel-IA, and Gel-MA, respectively). The successful synthesis was confirmed using 1H NMR, FTIR spectroscopies, and colorimetric TNBSA assay. The effect of chemical modification on the isoelectric point was studied through viscosity and electrophoretic mobility measurements. The evolution of the storage (G') and loss (G'') moduli was employed to determine thermoreversible gelation points of modified and unmodified gelatins. The safety of modified gelatin derivatives was assessed with an in vivo slug mucosal irritation test (SMIT) and an in vitro MTT assay utilizing human pulmonary fibroblasts cell line. Two different model dosage forms, such as physical gels and spray-dried microparticles, were prepared and their mucoadhesive properties were evaluated using a flow-through technique with fluorescent detection and a tensile test with ex vivo porcine vaginal tissues and sheep nasal mucosa. Gelatins modified with unsaturated groups exhibited superior mucoadhesive properties compared to native gelatin. The enhanced ability of gelatin modified with these unsaturated functional groups is due to the formation of covalent bonds with cysteine-rich subdomains present in the mucin via thiol-ene click Michael-type addition reactions occurring under physiologically relevant conditions.

Oat-based milk alternatives: the influence of physical and chemical properties on the sensory profile.

Oat-based milk alternatives (OMAs) have become increasingly popular, perhaps due to their low allergenicity and preferred sensory attributes when compared to other milk alternatives. They may also provide health benefits from unique compounds; avenanthramides, avenacosides, and the dietary fibre beta-glucan. This has led to a variety of commercial options becoming available. Being a fairly new product, in comparison to other plant-based milk alternatives (PBMAs), means little research has been undertaken on the sensory profile, and how it is influenced by the physical and chemical properties. This study investigated the sensory, physical and chemical profiles of current commercially available OMAs, that varied in fortification, use of stabilisers, and oat content. The volatile compounds and their respective aromas were analysed using solid phase microextraction followed by gas chromatography mass spectrometry (GC-MS) and gas chromatography-olfactometry (GC-O). Liquid chromatography mass spectrometry (LC-MS) was used for identification of avenanthramides and avenacosides. Particle size and polydispersity index (PDI) were analysed using a Mastersizer and Zetasizer, respectively, with colour analysis carried out using a colourimeter, and viscosity measurements using a rheometer. Descriptive sensory profiling was used to assess the impact on the sensory characteristics of the different samples and the sensory data acquired were correlated with the instrumental data. Samples with smaller particle size appeared whiter-both instrumentally and perceptually. The only clear plastic packaged product differed substantially in volatile profile from all other products, with a higher abundance of many volatile compounds, and high overall perceived aroma. Avenanthramides and avenacosides were present in all samples, but differed significantly in abundance between them. The results suggested smaller particle size leads to whiter colour, whilst differences in processing and packaging may contribute to significant differences in aroma. Astringency did not differ significantly between samples, suggesting that the variation in the concentrations of avenacosides and avenanthramides were below noticeable differences.

Dynamic Simulation Platform Aids Deep Transient Tests, Well-Control Safety

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215454, “Enhancing Well-Control Safety With Dynamic Well-Control Cloud Solutions: Case Studies of Successful Deep Transient Tests in Southeast Asia,” by M. Ashraf Abu Talib, SPE, M. Shahril Ahmad Kassim, and Izral Izarruddin Marzuki, SPE, Petronas, et al. The paper has not been peer reviewed. _ The complete paper addresses challenges related to well control and highlights the successful implementation of deep transient tests (DTT) in an offshore well performed with the help of a dynamic well-control simulation platform. The paper aims to provide insights into the prejob simulation process, which ensured a safer operation from a well-control perspective. Additionally, a comparison between simulated and actual sensor measurements during the DTT operation is presented. DTT DTT is a formation-testing (FT) method that allows pressure transient tests that reach deeper into the formation compared with conventional interval pressure transient tests (IPTT). DTT enables the testing of formations with higher permeability, greater thickness, and lower viscosity and real-time measurement of crucial parameters. During a DTT, formation fluid is pumped from the reservoir; upon stopping the pump, the formation pressure begins to recover as fluid further from the wellbore replaces the extracted fluid. By analyzing the resulting pressure transient, properties such as formation permeability, permeability anisotropy, and other characteristics can be determined. DTT allows for a better understanding of reservoir characteristics and rock heterogeneity. When properly designed and executed, DTT can reveal potential baffles and boundaries within the radius of investigation. A further advantage of DTT over drillstem tests (DST) is its minimal fluid flow, which allows for the attainment of objectives while contributing to the United Nations sustainable development goals. In DTT operations, the FT tool is connected to the drillpipe through a circulating sub and a slip joint. The circulating sub plays a critical role in DTT operations because it enables the continuous mixing of pumped formation fluid with circulated mud and facilitates its transportation to the surface (Fig. 1). Typically, a constant circulation rate ranging from 100 to 250 gal/min is maintained. During circulation, the annular preventer is closed and the mud/hydrocarbon mixture is directed through the choke line to the mud/gas separator (MGS) once it reaches the surface. No formation fluids are flared during DTT operations. Instead, the circulated oil is retained in the mud and only small amounts of gas are vented. By use of a slip joint, the FT remains anchored to the borehole wall. A high-resolution pressure gauge is used to capture and interpret even minor pressure fluctuations during the pressure transient buildup.

Determining the bulk viscosity in clay–sand mixtures: A combined investigation with slump tests and lattice Boltzmann simulations

Viscosity measurements for clay slurry and sand mixtures can be challenging for standard rheometers because of the sand particles. To solve this, we suggest combining slump test experiments with numerical simulations. Slump tests are performed on clay–sand mixtures, with the sand's volume fraction varying between 0≤ϕ≤0.32. The run-out distance of the slump is tracked over time using a high-speed camera. By comparing the results of lattice Boltzmann simulations with the experimental data, we can accurately estimate the mixture's overall viscosity. Our findings reveal that fluid consistency increases significantly with ϕ, consistent with predictions made by the Maron–Pierce formula.