Viscosity Values Research Articles

Experimental investigation of the effects of dispersed nanoalumina additive on plastic viscosity and yield stress values of cement-based grouts with fly ash

The effects of nanoalumina (n-Al2O3) additions at various proportions by mass (0.0%, 0.3%, %0.6, 0.9%, 1.2%, and 1.5%) on plastic viscosity and yield stress values of cement-based grout replacement with fly ash at different contents (0% for control purposes, 5%, 10%, 15%, 20%, 25%, and 30%) were experimentally studied in this work. To minimize nanoalumina precipitation in free water and to provide homogeneous dispersion in water by removing these adhering nanopowders from each other, the ultrasonication method was applied in this study. Test results showed that shear thickening (dilatant) behavior was observed in all grout samples. The flowability of cement-based grouts containing fly ash considerably increases with the amount of nanoalumina added to the grout samples. The addition of nanoalumina and fly ash together in the grout mixes caused a considerable decrease in the yield stress value of these mixtures. Moreover, using all the experimental data obtained, an artificial neural network has been developed to predict the plastic viscosity and yield stress values. The developed model has been able to predict plastic viscosity with an average error rate of -0.17% and yield stress with an average error rate of 0.24%.

Optimization Study of a High-Efficiency Preservative for Ammonia-Free Concentrated Natural Rubber Latex

Ammonia is commonly used as a preservative in the production of concentrated natural rubber latex (CNRL) and latex products; however, it poses a serious risk to human health and the environment. In this study, we investigated a thioacetamide derivative (TD) as a preservative of ammonia-free CNRL and the optimization of a stabilization system comprising potassium hydroxide (KOH), lauric acid (LA), and sodium dodecyl sulfate (SDS) to enhance its preservation effect. The results revealed that an optimal amount of TD (0.03%) can effectively maintain the stability of CNRL, inhibit the increase in volatile fatty acid number (VFA number), maintain stable viscosity values, and improve the mechanical stability time (MST). However, increasing the TD dosage results in an increase in both the viscosity and VFA number and a decrease in MST. KOH was used to regulate the pH value of CNRL. It was also found that it can enhance considerably the mechanical properties of CNRL dry films and accelerates the vulcanization of vulcanized film; however, an excessive amount causes latex thickening. LA proved essential for improving the MST and reducing latex viscosity, thereby substantially enhancing the stability and processability of pre-vulcanized latex, but an excessive amount is detrimental to the curing speed and final mechanical strength. SDS can rapidly improve the MST and reduce the viscosity, but it negatively affects the surface molding of dry rubber films. In conclusion, KOH, LA, and SDS at appropriate dosages play a balancing and complementary role in the preparation of ammonia-free CNRL. Upon analyzing diverse performance metrics of CNRL, it has been determined that the optimal TD dosage ranges from 0.02 to 0.03% for maximum efficacy. The KOH dosage should be maintained within 0.1–0.15% to achieve the most favorable outcome, while the LA dosage is advisable to be kept between 0.06 and 0.1%.

Vi-PLUS: Pioneering Plane-Wave Ultrasound to Assess Breast Glandular Tissue in Healthy Women—A Pilot Study

Background/Objectives: This study pioneers the application of the ViPLUS module, utilizing plane-wave ultrasound to measure breast tissue viscosity and elasticity. The primary goal was to establish normal reference values for viscosity in healthy women. Secondary objectives included exploring correlations between breast tissue viscosity and breast density categories, hormonal influences, and menstrual cycle phases. Methods: A prospective study was conducted on 245 asymptomatic women. Viscosity and elasticity measurements were obtained using the ViPLUS module, ensuring high reliability with stringent quality control measures. Data were statistically analyzed to evaluate correlations and group differences. Results: The median viscosity value for normal breast parenchyma was 1.7 Pa.s, with no significant variations based on breast density, menopausal status, or menstrual cycle phase. A strong correlation (rho = 0.866, p < 0.001) was observed between elasticity and viscosity values. Conclusions: The findings suggest that breast viscosity is consistent across diverse physiological states, indicating its potential as an independent diagnostic marker. This parameter could be pivotal in future breast cancer screening strategies, especially for younger women and those with dense breasts.

Ultrasonic assisted enzymolysis based modification of native banana starch - A comprehensive analyses of the structural, morphological, rheological and textural properties.

Native banana starch (NS) has few limitations, such as poor solubility, low resistance to shear, temperature, and inconsistent retrogradation. This study investigates the effects of mono (α-amylase, pullulunase) and sequential enzymatic modifications of NS along with the application of ultrasound to enhance its functional attributes. Starch modified with α-amylase alone and along with ultrasound resulted the lowest amylose (20.23 %), resistant starch (28.22 %), higher rapidly digestible starch (48.92 %). Whereas pullulanase modification resulted in higher amylose (38.14 %), resistant starch (52.72 %) and therefore the better swelling power and water holding capacity. The retrogradation negatively associated with the solubility of these modified starches is outlined through the static viscosity measurements. Ultrasound enhanced the efficiency of enzymes by altering the structure of starch granules, confirmed through SEM analysis and provided differentiated thermal stability as observed through viscosity and enthalpy values from DSC. The dual sequential enzymatic treatment with ultrasound also significantly improved the starch solubility by altering the structure as evidenced through XRD and FTIR analysis. NMR 1H spectra revealed distinct variations in the anomeric peaks and hydroxyl regions of modified starches. Cluster analysis highlighted the unique characteristics of ultrasound-assisted starches.

Comparative toxicity study of hyaluronic acid fillers crosslinked with 1,4-butanediol diglycidyl ether or poly (ethylene glycol) diglycidyl ether.

Dermal fillers comprising injectable hyaluronic acid (HA) are widely used for soft tissue augmentation, often using crosslinking agents such as 1,4-butanediol diglycidyl ether (BDDE) or poly (ethylene glycol) diglycidyl ether (PEGDE). Here, we assessed the physical properties, toxicity, and inflammatory reactions of HA fillers crosslinked with either BDDE (HA-BDDE filler) or PEGDE (HA-PEGDE filler) in in vitro and in vivo investigations. The HA-PEGDE filler exhibited higher G', tan δ, G*, and complex viscosity values compared to the HA-BDDE filler, while maintaining similar cohesivity. The filler extracts were used to evaluate cytotoxicity. HA-PEGDE filler extracts exhibited reduced cytotoxicity, oxidative stress, and inflammation in human keratinocytes (HaCaTs) and fibroblasts (HDFs) than that of HA-BDDE filler extracts. In animal studies, SKH1-hairless mice were injected subcutaneously with varying volumes of fillers and euthanized at 1- and 4-weeks post-injection. Compared with the HA-BDDE filler, the HA-PEGDE filler displayed favorable biocompatibility, decreased tumor necrosis factor (TNF)-α and interleukin (IL)-1β expression and reduced inflammatory cell infiltration. Our results demonstrate that the HA-PEGDE filler has comparable rheological properties and lower toxicity than the HA-BDDE filler, suggesting its suitability as an alternative in applications where minimal inflammatory response is crucial.

CIPM key comparison of viscosity CCM.V-K4

Main textThis report describes the fourth CCM key comparison in capillary viscometry among twelve National Metrology Institutes (NMIs), of which, nine NMIs maintain an independent viscosity scale and three NMIs do not maintain an independent viscosity scale. The comparison was carried out between January 8th 2018 and April 30th 2018. Two samples of Newtonian liquids with nominal kinematic viscosities of 170 mm2/s at 20°C, 65 mm2/s at 40°C and 10 mm2/s at 100°C for sample A and 10 000 mm2/s at 10°C 4 600 mm2/s at 20°C and 120 mm2/s at 100°C for sample B. Both samples were prepared by CENAM and provided to each one of the participants NMIs. For each of the samples at three temperatures, a total number of 64 measurements were carried out by the participants. From the values reported for the viscosity measurements, the key comparison reference values (KCRV) for six data sets were calculated. The degrees of equivalence were evaluated by the difference of the reported viscosity value with the KCRV. It was found that 9 measurements (14%) showed a degree of equivalence greater than the estimated uncertainty for the degree of equivalence.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Effects of supercritical carbon dioxide‐ethanol cocoa butter addition in cocoa butter‐based salad dressings

AbstractAddition of cocoa butter containing phytosterols and antioxidants into food products can provide additional health benefit towards consumers. This work aimed to extract cocoa butter from cocoa beans using supercritical fluid extraction to formulate salad dressing containing blends of soybean oil and cocoa butter and compared it with commercial salad dressing. The most similar (insignificant different) characteristics as the control sample in terms of consistency index, flow index, apparent viscosity and crossover value were 10%–35% cocoa butter salad dressing (CBSD). In contrast, the 30% CBSD shows insignificant difference of emulsion stability compared to commercial salad dressing. The most desirable ratio of cocoa butter to be added into salad dressing was 30%. The findings may benefit the local cocoa and salad dressing producer on product diversification.

Formulation of Face Serum Combining Pedada Leaf Extract (Sonneratia caseolaris L.) and Kencur Rhizome Extract (Kaempferia galanga L.) As an Antioxidant Cosmetic Preparation

Plants containing natural bioactive compounds with antioxidant activity have the potential to be utilized and formulated into cosmetic products. Pedada (Sonneratia caseolaris L.) leaves, a type of mangrove plant and aromatic ginger (Kaempferia galanga L.) rhizomes are two plants known for their high antioxidant activity. This study aimed to formulate facial serum using a combination of pedada leaves and aromatic ginger rhizome extracts and to evaluate the antioxidant activity of the formulations. The extraction of pedada leaves and aromatic ginger rhizomes was performed using the maceration method with 96% ethanol. Antioxidant activity was determined using the DPPH method. The facial serum was formulated with combinations of pedada leaves and aromatic ginger rhizomes in ratios of 1:1 (F1), 2:1 (F2), and 3:1 (F3). The serum formulations were evaluated for organoleptic properties, homogeneity, pH, viscosity, spreadability, stability, and irritation potential. The results indicated that the IC50 values of pedada leaves and aromatic ginger rhizome extracts were 10.78 ppm and 634.41 ppm, respectively. The best combination was a 3:1 ratio, which yielded an IC50 value of 15.74 ppm. The most effective serum formulation was F2, with an IC50 value of 394.98 ppm. The pH values of serums F0, F2, and F3 were 6.23, 5.72, and 5.43, respectively, and the stability test at 5°C, 28°C, and 40°C for three months showed pH values ranging from 4.5 to 6.5. The viscosity values of serums F0, F2, and F3 were 655, 1810, and 2776 cps, respectively. Acute dermal irritation tests on rabbits indicated that serum formulations F2 and F3 showed no adverse responses

Extraction and bioactivity assessment of bio‐oil from Kappaphycus alvarezii biomass using the Bligh, Dyer and Soxhlet method

AbstractThe lipid composition and algal oil content in red macroalgae play a crucial role in sustainable biofuel and bioactive compound production. In the present study, various extraction methods including biomass pretreatment through ultrasonication and conventional lipid extraction techniques such as Bligh & Dyer and Soxhlet were employed for lipid extraction from Kappaphycus alvarezii. Among these methods, pretreatment of ultrasonication combined with solvent extraction (PT + SE) resulted in highest extraction yield of 21.5% ± 0.38%, surpassing the yield achieved by the Bligh‐Dyer method (PT + BD) and the control method, which yielded 19.42% ± 0.1% and 10.7% ± 0.15%, respectively. PT + SE oil possesses lower values in molecular weight, viscosity, and density when compared to PT + BD oil. The trans‐esterified samples of PT + BD (T1) and PT + SE (T2) respectively demonstrated greater efficiency in converting methyl esters, with T2 achieving a conversion rate of 92% ± 0.21%, while T1 achieved 84.15% ± 0.15%. It was observed that T2 had a high scavenging rate of 86.42% ± 0.22% indicating its significant ability to neutralize free radicals. In contrast, T1 exhibited a slightly lower scavenging rate of 69.56% ± 0.1%, when compared to T2. T2 sample demonstrated remarkable proteinase inhibition of 79.16% ± 0.18, comparable to salicylic acid, indicating the presence of potent anti‐inflammatory salicylic acid analogues in the algal oil. Both lipid‐extracted oil (T1and T2) showcased significant antioxidant and anti‐inflammatory activities, with T2 oil demonstrating superior inhibition of free radicals and proteinase enzymes.

Eco-Friendly Hydrogels Loading Polyphenols-Composed Biomimetic Micelles for Topical Administration of Resveratrol and Rutin

In this study, we describe the development of hydrogel formulations composed of micelles loading two natural antioxidants—resveratrol and rutin—and the evaluation of the effect of a by-product on the rheological and textural properties of the developed semi-solids. This approach aims to associate the advantages of hydrogels for topical administration of drugs and of lipid micelles that mimic skin composition for the delivery of poorly water-soluble compounds in combination therapy. Biomimetic micelles composed of L-α-phosphatidylcholine loaded with two distinct polyphenols (one non-flavonoid and one flavonoid) were produced using hot shear homogenisation followed by the ultrasonication method. All developed micelles were dispersed in a carbomer 940-based hydrogel to obtain three distinct semi-solid formulations, which were then characterised by analysing the thermal, rheological and textural properties. Olive pomace-based hydrogels were also produced to contain the same micelles as an alternative to respond to the needs of zero waste and circular economy. The thermograms showed no changes in the typical profiles of micelles when loaded into the hydrogels. The rheological analysis confirmed that the produced hydrogels achieved the ideal properties of a semi-solid product for topical administration. The viscosity values of the hydrogels loaded with olive pomace (hydrogels A) proved to be lower than the hydrogels without olive pomace (hydrogels B), with this ingredient having a considerable effect in reducing the viscosity of the final formulation, yet without compromising the firmness and cohesiveness of the gels. The texture analysis of both hydrogels A and B also exhibited the typical behaviour expected of a semi-solid system.

Calculation method of dynamic loads in plunger deep-well pumps for oil production

Relevance. Plunger units, in particular rod and rodless ones with surface and submerged drive, are widely used in the oil industry for extraction of high-viscosity emulsion from marginal wells. The main advantage of such units is the possibility to operate in conditions of highly viscous emulsions with viscosity values up to 200–300 cPs. However, there are peculiarities of plunger unit operation, which lead to some complications. One of the most widespread complications is high wellhead pressure, which leads to increased dynamic loads on pump and drive units. Qualitative and precise definition of wellhead pressure value depending on well and unit parameters will contribute to more effective design, operation and evaluation of plunger unit reliability. Known studies and methods of wellhead pressure determination have limitations related to single-factor influence of some parameter on wellhead pressure values. This approach is not suitable for taking into account the simultaneous influence of several parameters. Aim. Development of calculation methodology, which allows taking into account complex influence of well operation parameters on wellhead pressure value and dynamic loads on plunger rods. Objects. Fund of wells equipped with borehole rod pump units. Methods. Statistical and regression analysis of the stock of wells equipped with downhole rod pumping units, development of a neural network. Results. A stock of wells equipped with downhole sucker-rod pumps, the technological mode of which is provided by one of the companies of Privolzhsky federal district, was investigated as an example, on the basis of the specified stock the factors influencing the value of wellhead pressure were established and the technique on its forecasting was developed. The authors have proposed the method for discarding the data with a wide range of values when analyzing the factors affecting the wellhead pressure. The method consists in excluding the values of fluid viscosity not lying on the "hump" characteristic of the function "fluid viscosity – watercut". The authors developed the calculation method based on regression dependences and neural network. It allows forecasting more accurately the value of loads on the pump rods.

Heat treatment impact on structural-rheological properties of high-parafin oil

Relevance. The pipeline transportation of heavy oils from the extraction site to the processing point is associated with serious problems due to their high viscosity and pour point. Oil deposits form quickly during pumping and causing flow reduction in pipe. Moreover, the increased content of hydrogen sulfide and chloride salts leads to increased rate of corrosion. Structural and mechanical properties and the yield point of highly pourable paraffinic oils depend on a variety of factors, like oil thermostatting temperature. Studying the impact of the heat treatment temperature of highly paraffinic resinous oil on its mobility will allow reducing energy consumption and optimizing the technology of oil pumping and transporting in winter conditions. Aim. To identify the critical temperature ranges for heat treatment of highly paraffinic resinous oil from the Yuzhno-Mayskoe field based on the analysis of data on structural and rheological behaviors, composition of oil sediments and changes in the radii of oil aggregates formed in the studied oil under various heat treatment conditions. Methods. Oil rheological properties were determined using a HAAKE Viscotester iQ rotational viscometer with HAAKE RheoWin measuring device and control system; oil pour point was analyzed using “Kristall” low-temperature indicator of petroleum products meter; asphaltenes were isolated using the “cold” Golde method; oil composition was determined by column liquid adsorption chromatography; oil particle size was recorded by a Photocor Complex spectrometer for dynamic and static light scattering with DynaLS data processing program. Results. The authors have studied heat treatment temperature impact on the viscosity-temperature and energy characteristics of highly paraffinic tarry oil, formation and composition of asphalt, resin and paraffin deposits. They established that the critical temperature of heat treatment is 40°C. At this temperature the densest crystallization structure is formed in the studied oil, characterized by high values of both viscosity, intensive formation of sediment, activation energy of viscous flow and internal energy of destruction of the dispersed structure. It was shown that with photon correlation spectroscopy, during oil heat treatment at 40°C, a spontaneous size increase of oil aggregates occurs in the temperature range of 35–25°C.

IN VITRO ASSESSMENT OF ANTIUROLITHIATIC ACTIVITY OF APIGENIN WITH NITRIC ALGINATE VARIATION IN NANOSUSPENSION

Kidney stones are hard kidney material, such as stones that originate from minerals and salts. Alternative therapy using medicinal plants as anticalculi is an option for treating kidney stones. One plant with anticalculi activity is celery, which contains various active chemical compounds, including apigenin. Apigenin is a diuretic that can help the kidneys remove excess fluid and salt from the body. However, apigenin has low solubility in water. To overcome the limited solubility of apigenin, nanosuspensions were prepared. This study aimed to formulate a nanosuspension, evaluate its preparation, and test it in vitro. This formula uses the concentration of the suspending agent, Na. The different alginates were F0 without active substances (0%) and F1 (1%), F2 (2%), and F3 (3%). The evaluation of the preparation includes tests for pH, viscosity, specific gravity, particle size, zeta potential, and adsorption efficiency. The results showed that the preparation had an average pH value of 4-7, an average viscosity value of 78-162 cP, a specific gravity of 0.98-1.02 g/mL, the preparation had a particle size of 928–974 nm, zeta potential of-26, 3 to -41.7, and an average entrapment efficiency of 99.63%-99.64%. Apigenin nanosuspension preparations can dissolve kidney stone calcium at 1800-7800 ppm. The test results showed that the apigenin nanosuspension has the potential to dissolve calcium kidney stones. Keywords: kidney stones, apigenin, in vitro, nanosuspension

Formation of Amyloid-Like Conformational States of β-Structured Membrane Proteins on the Example of the OmpF Porin from the <i>Yersinia pseudotuberculosis</i> Outer Membrane

The work presents the results of an in vitro and in silico study of the formation of amyloid-like structures under harsh denaturing conditions by the nonspecific OmpF porin of Yersinia pseudotuberculosis (YpOmpF), a membrane protein with a β-barrel conformation. It has been shown that in order to obtain amyloid-like porin aggregates, preliminary destabilization of its structure in a buffer solution with an acidic pH value at elevated temperature, followed by long-term incubation at room temperature is necessary. After heating at 95 °C in a solution with pH 4.5, significant conformational rearrangements are observed in the porin molecule at the level of the tertiary and secondary structure of the protein, which are accompanied by an increase in the content of the total β-structure and a sharp decrease in the value of the characteristic viscosity of the protein solution. Subsequent long-term exposure of the resulting unstable intermediate YpOmpF at room temperature leads to the formation of porin aggregates of various shapes and sizes that bind thioflavin T, a specific fluorescent dye for the detection of amyloid-like protein structures. Compared to the initial protein, early intermediates of the amyloidogenic porin pathway, oligomers, have been shown to have increased toxicity to Neuro-2aCCL-131™ mouse neuroblastoma cells. The results of computer modeling and analysis of changes in intrinsic fluorescence during protein aggregation suggest that during the formation of amyloid-like aggregates, changes in the structure of YpOmpF affect not only areas with an internally disordered structure corresponding to the external loops of the porin, but also the main framework of the molecule, which has a rigid spatial structure inherent to β-barrel.

Physicochemical, Functional, Sensory, and Rheological Properties of Traditional Tarhanas from the Central Anatolian Region

Tarhana, produced in Anatolia using a variety of production techniques, is a traditional fermented product made from a mixture of yogurt, wheat flour, vegetables, and spices. Tarhana, with its high nutritional value, makes a positive contribution to human nutrition in terms of health. In this study, the chemical (moisture, ash, protein, fat, titratable acidity, salt, aw, total sugar), functional (total phenolic content, total antioxidant capacity, water and fat holding capacity), viscosity and sensory properties of tarhana produced in Aksaray, Ankara, Eskişehir, Kayseri, Konya, Nevşehir and Sivas provinces of Central Anatolia region were determined. The moisture contents of the tarhana samples were found to be 17.36-7.52%, protein contents 12.62-8.88%, ash contents 7.4-3.66%, fat contents 4.23-0.81%, titratable acidity values 21.5-7.5%, pH values 5.4-4.04. The highest viscosity value was found in Sivas Tarhana with 1721 cp. Kayseri and Konya tarhanas had the highest total phenolic content and antioxidant capacity. In terms of sensory properties, the most admired tarhana was the tarhana from Aksaray province, and the least admired tarhana was the tarhana from Ankara province. In conclusion, when we compared the tarhana commonly consumed as soup in the Central Anatolian region, it was found that the physical and chemical properties, as well as the taste preferences, varied regionally.

Initial experiences with dynamic, quality indicator-based multimodal tissue analysis (M-Ref) with parallel assessment of viscosity and shear wave elastography in liver parenchyma alterations1.

Modern ultrasound technology enables detailed tissue morphology analysis. A novel approach involves measuring viscoelasticity or viscosity. This pilot study investigates the potential of a novel high-end ultrasound system with dynamic quality indicators and the M-Ref tool. Using a novel premium high-end ultrasound system (Resona A20/Mindray), comparative investigations were conducted on 52 patients, evaluating B-mode morphology, shear wave tissue elastography (STE), and viscosity (STVi) of the liver parenchyma. The study utilized a cohort of 25 healthy volunteers as a control group. The examinations were performed intercostally using a multifrequency convex probe SC7-1U (1-7 MHz) and breath-hold technique, ensuring that at least the highest or second-highest score in the dynamic quality control (5 stars) was achieved. Measurements were made in a color-coded region with a maximum 2 cm diameter and a depth of no more than 2 cm, avoiding bile ducts or blood vessels, at a depth up 2 cm from the liver capsule. A minimum of 10 measurements were taken for each parameter: liver steatosis (based on acoustic attenuation coefficient, USAT), viscosity (STVi), and shear wave elastography (STE) with correlation to fibrosis grade. Reference values for the control group were <1.4 m/s and <5 kPa for STE, with cirrhosis criteria defined as values >2.6 m/s and >15 kPa. For steatosis, values up to 0.5 dB/cm/MHz were considered normal, while values >0.8 dB/cm/MHz indicated fatty liver. Viscosity values <1.7 Pa.s were deemed normal, with >3.6 Pa.s indicating significant abnormality. Major causes of increased viscosity included severe steatosis, active hepatitis, hepatic tumors, or post-ablative states. In all cases, a high-quality indicator score (>93%) was achieved with at least 4/5 top reference markers in green. This pilot study confirms the comprehensive capabilities of multimodal imaging for tissue characterization using B-mode, elastography, and new techniques for assessing viscoelasticity. However, extensive multicenter evaluations will be needed to definitively establish reference values specific to the type of transducer and equipment used.

Polythermal studies of the water – propylene glycol systems by densitometry, viscometry and spin probes method

Based on the determined values of density, dynamic viscosity and molar volumes, the thermodynamic activation parameters and excess thermodynamic activation parameters of viscous flow at temperatures from 293.15 K (20°C) to 313.15 K (40°C) were calculated for the mixed binary solvents water – propylene glycol (PG). Using the isotherms at 298.15 K, assumptions were made about the composition regions of binary solvents with different structural organizations. The structure of the mixed solvent has an impact on the various functional characteristics of the systems water – PG, and it could also influence the performance of medicinal products with a liquid dispersion medium. The density and excess density, as well as the dynamic viscosity and excess dynamic viscosity for systems water – PG were determined as a function of the PG concentration. Using the method of spin probes, it was demonstrated that changes in the dynamic viscosity of systems water – PG correlated with the alterations in the viscosity of the microenvironment of spin probe molecules. The viscosity of the microenvironment was also influenced by the interaction between molecules of dissolved spin probes and solvent molecules.

Study of the Effect of NaOH Type Alkaline Catalyst on the Physicochemical Characteristics of Used Cooking Oil Biodiesel

Dependence on fossil fuels causes significant environmental damage and increases costs and scarcity in the future. To overcome this problem, a transition to renewable energy is needed, one of which is biodiesel which can be obtained from used cooking oil. This study aims to convert used cooking oil that cannot be reused into biodiesel products. Biodiesel synthesis can be carried out by the transesterification process, using NaOH catalyst with concentration variations of 0.5%, 0.75%, 1%, 1.25%, and 1.5% of the total mass of oil. The test parameters are calorific value, density, viscosity and flash point as well as yield on used cooking oil biodiesel products. The test results show that the use of a catalyst concentration of 1% produces more optimal density, viscosity, and calorific value and flash point. Each value is 0.859 g / cm³, 2.34 cSt, 10,356 cal / g, and 139°C. However, the use of a catalyst concentration of 0.5% shows that the biodiesel product is less than optimal. This can be shown by the highest density, viscosity and flash point values of the catalyst concentration variations used. Each value is 0.88 g/cm3, 3.16 cSt and 178°C, while the calorific value is also low with a value of 9,689 cal/g. However, when viewed from the yield, the catalyst concentration of 0.5% produces the highest value of all catalyst concentration variations used with a value of 88%.

Hydrolysis Process of Red Sorghum Grains for Producing Bioethanol

As part of the effort to continuously enhance the development and utilization of bioenergy/bioethanol and to ensure its sustainability, using sorghum as a raw material for bioethanol production requires a study to obtain efficient hydrolysis conditions and achieve optimal bioethanol conversion. This research method is divided into two main parts: samples with pretreatment and without pretreatment. The pretreatments used NaOH solution (0.05% and 0.1%); soaking temperatures at 35,40 and 45oC; and soaking time at 30, 60, 90, and 120 minutes. The liquefaction and saccharification results with pretreatment showed a greater decrease in viscosity values after both liquefaction and saccharification, and the RS and DE results also demonstrated an increasing trend compared to samples without pretreatment. It is due to the presence of protein bodies in sorghum that inhibited hydrolysis without applying the pretreatment. The best result on the reduced sugar (RS) value achieved was 10.43%, and the DE value was 67.90%. Thus, the optimum operational condition was achieved with a sample with 0.05% NaOH soaking for 90 minutes at 45°C (A9). Subsequently, fermentation was carried out on sample A9 with pretreatment and sample without pretreatment (A0/B0). The alcohol obtained from fermentation with pretreatment was 9.5%, with a fermentation ratio (FR) of 86.97%. Meanwhile, the alcohol yield from fermentation for the sample without pretreatment was 8.9%, with an FR of 83.02%.

Preparation of Ti6Al4V Slurry for Digital Light Processing 3D Printing

Ti6Al4V powders have higher light absorption and density, which pose significant challenges for metal light curing. It is necessary to investigate the performance of Ti6Al4V slurries to achieve high‐quality green bodies. To optimize Ti6Al4V slurry for light‐curing printing, the influence of slurry components on the rheological and curing properties of slurry is studied. The viscosity values of slurries are measured under different solid loading, and it is found that the viscosity values of the slurry are proportional to the solids loading. It is found that the curing performance of the slurry with photoinitiators 819 is superior to that of the slurry with diphenyl (2,4,6‐trimethylbenzoyl) phosphine oxide as the photoinitiator 819. The effect of the concentration of dispersant KOS110 on the viscosity of slurry is measured, and the results show that the viscosity of the slurry is increased due to the bridging flocculation of the dispersant KOS110 in the slurry. It is found that green bodies can be printed successfully when the solid loading of Ti6Al4V slurry is 40 vol%, the concentrations of photoinitiator 819 and dispersant KOS110 are 1 and 3 wt%, respectively. The printing parameters are energy density of 336 mJ cm−2 and a model thickness of 20 μm.