High Temperature Viscosity Research Articles

Effect of Different Preservation Methods on some Physiochemical, Microbial and Sensory Properties of Doina as Fermented Cereal Dairy product

This study was conducted to synthesis of Doina the local cereal- dairy fermented product in Kurdestan region-Iraq by mixed Doo (skimmed butter milk) with fain burgul at size (1000-1500μm) produced from Muselly durum wheat, and storage for six months on Sun drying or Oven drying or freezing methods, the Doina mixture supplemented by Lactobacillus acidophilus and Lactobacillus plantarium as a probiotics, and identified by Commercial (API50 CHL) kit after six months of storage and evaluated the chemical, physical, microbial and sensory properties of final products. Significant difference ( P ≤ 0.05 ) between chemical composition of Doina in the different preservation methods (Sun drying, laboratory drying, Freezing) were found after storage. The rheological properties using of a sun-drying method (Traditional method) caused decreasing of gelatinization temperature in Doina mixture and it had a high amylograph maximum viscosity compared to freezing preservation method which gelatinized in high temperature and maximum viscosity in amylograph was low. There were significant differences ( P ≤ 0.05) between sensory evaluation of preserved Doina. Sun drying method had a high scores of sensory evaluation then laboratory method and freezing method.
 

Effects of Illitic Clay on the Phases, Microstructure, Physical Properties and Pyroplastic Deformation of Industrial Slag Ceramics.

Preparing ceramic materials is a meaningful way to treat and utilize industrial slags. In this work, high-performance and low-deformation industrial slag ceramics were prepared from Ti-extraction blast furnace slag and illitic clay. The phase composition and contents, microstructure, physical properties, and pyroplastic deformation of ceramic samples were investigated. With the increasing proportion of illitic clay, the main crystalline phase of ceramic samples changed from akermanite to Fe-bearing diopside. Moreover, the minor crystalline phases changed from perovskite and spinel to anorthite and titanite. The proportion of illitic clay was linearly related to the amorphous phase content. The dense microstructure comprised concentrated short-columnar and granular grains with a few isolated pores, whereas plate-like grains destroyed their denseness. An appropriate proportion of illitic clay helped to improve the physical properties, increase the high-temperature viscosity and reduce the deformation of the ceramics. The optimal proportion of illitic clay was 30%, and the prepared ceramic sample had a dense microstructure and excellent physical properties. Its bulk density was 2.82 g/cm3, bending strength was 62.17 MPa, and water absorption was 0.21%.

Quantum mechanical interpretation of the minimum viscosity of metallic liquids.

Possible fundamental quantum bounds for viscosity and many other physical properties have drawn serious considerations recently from diverse communities encompassing those studying quantum gravity, high-energy physics, condensed matter physics, strongly correlated electron systems, and "strange metals," to name a few. However, little attention has been paid by materials scientists and the fluid dynamics community, perhaps because of the general belief that quantum mechanics is of little consequence for classical fluid dynamics. Here, considering the extrapolated high-temperature viscosity of 32 metallic alloy liquids as representative of minimum viscosity, experimental results are presented and evaluated in terms of a number of quantum- and statistical-mechanics-based theories. The surprising result is that the experimental data are within one order of magnitude of estimates from those theories. That quantum mechanics could be of importance at such high temperatures in conventional classical fluids is quite interesting. Another surprise is that the minimum viscosities of metallic alloy liquids are not too different from an archetypal quantum liquid, such as He.

The effects of phosphorus pentoxide additions on the thermal, rheological, and structural properties of sodium borosilicate glass

This research has characterized the effects of P2O5 additions on the physical, chemical, thermal, rheological properties and the structure of SiO2-B2O3-Na2O glasses relevant to radioactive waste immobilization. Properties analysed include high-temperature viscosity, glass transition temperature (Tg) and structure. X-ray diffraction (XRD) confirmed a solubility limit of between 3.0 and 4.0 mol% P2O5 for the onset of crystallinity with formation of Na3PO4 and Na4P2O7 in annealed bulk glasses; and between 4.0 and 5.0 mol% P2O5 in unannealed (quenched) glasses. This difference in behaviour is attributed to the bulk glass annealing temperature being greater than Tg of phase-separated, phosphate-rich droplet phases present in the 4.0 mol% P2O5 glass, which promoted crystallization, where back scattered scanning electron microscopy (SEM) images suggested that phase separation had occurred as liquid-liquid phase separation, where there was evidence of a droplet like morphology in glasses containing between 4.0 and 6.0 molar % P2O5. However, the exact mechanism cannot be unequivocally confirmed as nucleation and growth based purely on phase morphology. Differential Thermal Analysis (DTA) and dilatometry showed modest increases in Tg with increasing P2O5 contents below the onset of crystallisation and a more substantial increase coinciding with the onset of crystallisation between 3.0 and 4.0 mol% P2O5. High-temperature viscosity measurements showed that increasing P2O5 contents led to increases in viscosity, with samples containing the highest P2O5 additions displaying non-Newtonian behaviour consistent with the presence of crystals in the melt at 950 °C. Raman difference spectra showed that the increase in P2O5 content resulted in characteristic peak intensities at 729 cm−1, 937 cm−1, 1000 cm−1, 1026 cm−1, 1109 cm−1 and 1445 cm−1 which were associated with phosphate species.

Online monitoring of oil film thickness of journal bearing in aviation fuel gear pump

As the key support of aviation fuel pumps, journal bearings are operated under extreme conditions of high temperature, high pressure and low viscosity media, therefore, the broken of the ultra-thin lubrication film is the main cause of lubrication failure and abnormal wear. However, the dynamic hydraulic lubrication (DHL) film is still blind due to the lack of non-destructive online monitoring techniques. This paper presents the study of ultrasonic-based measurement for the dynamic oil film thickness of fuel pump. The circumferential oil film thicknesses in a journal bearing are measured with the complex model and the resonance model, meanwhile, the minimum oil film thickness is extracted by fitting the measured points with the initial circle. Under varying operating conditions, the measured results are verified with classical DHL simulations, and the maximum relative error is shown to be lower than 15%.

Patient-specific 3D printed Poly-ether-ether-ketone (PEEK) dental implant system

Fused Filament Fabrication (FFF)-based 3D printing is an efficient technique for developing medical implants, but it is not very useful in developing small yet mechanically robust design-specific fixtures such as dental implants (<15 mm). Specifically, it is challenging to 3D print robust Polyetheretherketone (PEEK) small implants due to PEEK's high melting temperature and melt viscosity. However, in this study, we efficiently utilize high-temperature FFF to develop the first-of-its-kind patient-specific robust PEEK dental implants with high print resolution. Specifically, we explore the effects of critical FFF processing conditions on the mechanical properties of the implants and subsequently determine an optimized set of processing conditions that are essential in developing durable dental implant systems. Our results indicate that the 3D printed dental implants exhibit good fatigue properties and suffice the clinical and industrial requirements for dental implants. Furthermore, we prove that the 3D printed implants exhibit adequate mechanical durability even after simulated (accelerated) aging of 30 years.

Study on rheological properties of warm mix large proportion recycled asphalt

In order to explore the rheological properties of high content warm mix recycled asphalt binder, recycled asphalt was added into warm mix asphalt to prepare warm mix recycled asphalt. The optimum content of regenerant and Sasobit REDUX was determined by asphalt basic performance test and temperature scanning test. The chemical composition of recycled asphalt was studied by FITR. The rheological properties and low temperature crack resistance of warm mix recycled asphalt were analyzed by DSR and BBR tests, and the optimum content of recycled asphalt was determined. The results show that when the content of regenerant is 10%, its basic performance recovers to the level of base asphalt. Sasobit REDUX can reduce the high temperature viscosity of asphalt, and the optimum content is 1%. With the increase of recycled asphalt content, the shear modulus and phase angle of warm mix recycled asphalt gradually decrease, and its high temperature stability gradually increases. Under low frequency and high temperature conditions, warm mix recycled asphalt with 50% content has better high temperature deformation resistance. Under the action of stress, the strain accumulation decreases with the increase of the content of recycled asphalt. When the content of recycled asphalt is 50%, the ability of warm mix recycled asphalt to resist load deformation and temperature sensitivity in the middle temperature zone is similar to that of matrix asphalt, and it has good deformation resistance and low temperature crack resistance. Comprehensive analysis of the best content of recycled asphalt should be 50%, then warm mix recycled asphalt mixture has excellent road performance.

Structural and dynamic properties of MgO–Al2O3–SiO2 glasses from molecular dynamics simulations and NMR

Magnesium aluminosilicate glasses have a wide range of applications in composite fiber reinforcements, aircraft windshields, due to their excellent chemical stability and mechanical properties. In this work, molecular dynamics simulations were used to obtain the short- and medium-range structural evolution of MgO/Al2O3 in MgO–Al2O3–SiO2 glass. The structural information was verified using a combination of combining Raman and Nuclear Magnetic Resonance (NMR) spectroscopy. The composition-structure-property relationship of the MgO–Al2O3–SiO2 glasses was constructed, using high-temperature viscosity results calculated by the Einstein-Stoke equation. The results showed that with the increase of MgO/Al2O3 ratio, Mg2+ changed from charge compensator to network modifier, which led to the gradual depolymerization of the glass network. Moreover, with the gradual replacement of Si by Al in the glass network, the disorder of the glass system increases, evidenced by the high-frequency Raman bands and the average chemical shifts of [AlOn] (n = 4, 5) shift linearly. In addition, we found that the de-polymerization led to a decrease in viscosity and an increase in fragility. The viscosity is negatively correlated with both the fragility and the atomic diffusion coefficient. It provides a theoretical basis for improving the preparation process of MgO–Al2O3–SiO2 glass and optimizing the glass properties.

A novel epoxy-terminated polyethylene modified asphalt with low-viscosity and high storage stability

The storage stability of polyethylene (PE) modified asphalt is a major constraint to its wide application. In addition, PE raises the mixing and compaction temperature of asphalt, causing environmental pollution. The effective synthesis of stable and environmentally friendly PE modifiers is an important and challenging topic. We propose a strategy to reduce the molecular weight of PE while adding functionalized end group to PE. The obtained low molecular weight epoxy-terminated-polyethylene (EPE) for modified asphalt is storage stable, reduces mixing and compaction temperatures of asphalt, and reduces environmental pollution. The difference between the top and bottom softening points of asphalt containing 3 wt% and 5 wt% EPE was 1.25 °C and 0.7 °C, which exceeded most previously reported PE-modified asphalt. In addition, EPE, due to its low molecular weight, reduces the high temperature viscosity of asphalt, achieving lower mixing and compaction temperatures. Besides, dynamic shear rheometer (DSR) and multiple stress creep recovery (MSCR) data showed that the rheological properties of EPE modified asphalt were also significantly improved. This work will provide further guidance for the application of PE in asphalt.

Research on Ultra-High Viscosity Index Engine Oil: Part 1 - “Flat Viscosity” Concept and Contribution to Carbon Neutrality

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;In recent years, the realization of carbon neutrality has become an activity to be tackled worldwide, and automobile manufacturers are promoting electrification of power train by HEV, PHEV, BEV and FCEV. Although interest in BEV is currently growing, vehicles equipped with internal combustion engines (ICE) including HEV and PHEV will continue to be used in areas where conversion to BEV is not easy due to lack of sufficient infrastructures. For such vehicles, low-viscosity engine oil will be one of the most important means to contribute to further reduction of CO&lt;sub&gt;2&lt;/sub&gt; emissions. Since HEV requires less work from the engine, the engine oil temperature is lower than that of conventional engine vehicles. Therefore, the reduction of viscous resistance in the mid-to-low temperature range below 80°C is expected to contribute more to fuel economy. On the other hand, the viscosity must be kept above a certain level to ensure the performance of hydraulic devices in the high oil temperature range. In order to achieve both of these characteristics, an oil whose viscosity has smaller temperature dependency (flat viscosity oil) is required. The flat viscosity oil can be achieved by using a low-evaporative, low-viscosity base oil and an ultra-high viscosity index Viscosity Modifier. It proved the possibility to achieve fuel economy equal to or better than 0W-8 while maintaining 0W-16 equivalent high temperature viscosity. This technology is applicable for vehicles calibrated with either 0W-16 or 0W-8 without negative impact on fuel economy performance. The flat viscosity 0W-16 will improve the fuel economy of in-use vehicles calibrated with conventional 0W-16 oils in the market significantly. As a result, CO&lt;sub&gt;2&lt;/sub&gt; reduction can be achieved not only for new vehicles but also for vehicles in operation in the market that can contribute greatly to the carbon neutrality. In order for the flat viscosity oil to be widely used in the world, it is necessary to establish new engine oil specification.&lt;/div&gt;&lt;/div&gt;

Correction: Investigation of High Temperature Performance and Viscosity Characteristics of Modified and Unmodified Color Asphalt

Correction: Investigation of High Temperature Performance and Viscosity Characteristics of Modified and Unmodified Color Asphalt

New Model High Temperature Pasting Analysis of Fermented Cassava Granules

Cassava is a starchy food item eaten by millions worldwide in various forms. The product has been subjected to various analysis forms, including the viscosity capacity of different flours made from the product. In this study, cassava granules (Garri) were subjected to scanning electron microscopy (SEM) and laser diffraction particle size analysis to determine microstructure, after which the viscosity behavior was ascertained under high pressure with the new model high-temperature rapid viscosity analyzer (RVA HT 4800), which is capable of reaching a maximum of 140 °C. Viscosity comparisons were then made with the profiles obtained at 95 °C and 140 °C. The microstructure had intact starch cells and was free of extraneous materials or fungal hyphae. The granule size range was found to be 1–1800 µM. It was established that the holding, final, and setback viscosities were most affected and decreased by at least 80% when the samples were subjected to the 140 °C HT profile. The peak time at 95 °C in yellow and white Garri samples of both brands averaged nine minutes, whereas it was 5 min at 140 °C profile. The white Garri samples tolerated the high temperature better based on breakdown viscosity values and may be used for making food products that require tolerance to high temperatures. An opportunity exists to re-evaluate different Garri varieties with the new model RVA to establish behavior at very high temperatures.

Compositional and Morphological Investigations of Roman Glass from Cremation Deposits at Birdoswald Fort on Hadrian’s Wall, UK

Several different types of burial were identified during the excavation of the Roman military cemetery associated with the fort at Birdoswald, on Hadrian’s Wall (UK). Fragments of glass vessels and glass beads were recovered from many of the cremation deposits, as they were commonly used during cremation rituals, and many of these had been affected by heat. X-ray fluorescence spectroscopy and scanning electron microscopy were used to investigate the raw materials, colorants and opacifiers employed to produce the glass assemblage. Most of the large fragments are transparent with a blue-green colour, with a composition typical of recycled glass. The smaller fragments are from beads and are coloured and sometimes opaque. Colourants and opacifiers characteristic of Roman glass were added in this glass formulation, including cobalt-based compounds (blue glass), copper alloys (green glass), white calcium antimonate, and yellow lead antimonate. The multianalytical approach of this research has allowed for the distinguishing of the extreme depletion of sodium on the surface of the melted glass fragments due to the exposure to high temperatures during the cremation process, followed by surface weathering in a burial environment. Based on the chemical composition of the bulk of the samples, a model of high temperature viscosity of glass was applied in order to assess the cremation temperature in the pyre, providing relevant information about funerary rituals and cremation technology in Roman Britain.

Effect of Organic Viscosity-Reducing Warm-Mix Agent on the Performance of Rubber Asphalt

Dynamic mechanical analysis (DMA) and other evaluation methods were used to investigate the effect of WS-1, an organic viscosity-reducing temperature mixing agent, on the rheological and conventional properties of warm-mix rubber asphalt (WMRA). The results demonstrated that the WS-1 warm-mix agent exhibited an excellent viscosity-reducing effect and that, with the increasing of WS-1 content, the high-temperature viscosity of the WMRA decreased significantly. The viscosity and softening point of the WMRA increased at 60 °C simultaneously, with the softening point increasing by about 15 °C. The penetration and ductility decreased by about 1 mm and 6 cm, respectively, and the activation energy (Eη) and temperature sensitivity increased. These results indicated that WS-1 could improve the high-temperature performance of WMRA but had an adverse effect on its low-temperature performance. Upon using temperature scanning for the WMRA, the addition of WS-1 significantly increased the rutting factor (G*/sin δ) of the WMRA and greatly improved its rutting resistance within the temperature range examined. The addition of WS-1 changed the viscosity of WMRA, thus affecting the hot-storage stability of WMRA at high temperatures.

Study on the Effect of Regeneration Agent on the Viscosity Properties of Aged Asphalt.

China’s highway asphalt pavement has entered the stage of major repair, and improving the utilization rate of recycled asphalt pavement (RAP) is the main issue. The key link affecting the performance of recycled asphalt mixtures is the regeneration of aged asphalt, and the effect of the regenerant dosing on the high-temperature performance and viscosity of aged asphalt is the main content to be studied in this research. The aging behavior of asphalt seriously affects the roadworthiness of asphalt mixtures. In this study, we investigated the effect of changes in the microscopic properties of the aged asphalt on its viscosity properties during regeneration using gel permeation chromatography (GPC), Fourier-transform infrared spectroscopy (FTIR), and atomic force microscopy (AFM) as well as Brinell viscosity tests. This study simulated asphalt aging by the RTFOT test, and then we obtained an aged asphalt with a needle penetration of 30. We prepared different regenerated asphalts by adding regeneration agent with doses of 2%, 4%, and 6% to the aged asphalt. The results showed that the regeneration agent could effectively reduce the viscosity of the aged asphalt, which can play a positive role in improving the construction and ease of the aged asphalt. Rejuvenation agents affected the aging asphalt sulfoxide and carbon group indices. Moreover, rejuvenation agents can also significantly reduce the intensities of their characteristic functional group indices. The results of the AFM test showed that the increase in the dose of regeneration agent increased the number of the asphalt bee-like structures and decreased the area of individual bee-like structures. The results of the GPC test were consistent with the results of the AFM test, and the increase in the dose of regeneration agent reduced the asphalt macromolecule content. The viscosity properties and microstructure of the aged asphalt changed positively after the addition of the regeneration agent, indicating that the regeneration agent had a degrading and diluting effect on macromolecules.

Preparation of A High-Performance Frit Glaze Using High-Potassium Feldspar

In this study, a lead-free transparent frit glaze was fabricated using a high potassium feldspar ore from Northeast China. The effect of the potassium feldspar grade and compositions of CaO and ZnO content on the performance of a block glaze was studied. The study on the effects of the potassium feldspar grade on the molten glaze demonstrated that as the grade of the potassium feldspar in glaze increases, the glaze appearance, gloss, hardness, and thermal stability of the sample become better, and the roughness decreases. CaO and ZnO in glaze have good fusible effects on the performance of melt glaze: the high-temperature viscosity of glaze decreases, and the surface tension and quality of the glaze increase. Moreover, an optimal lead-free frit glaze formula was determined, which provided insight into the production of high-added-value products using complex and refractory potassium feldspar ore.

Characteristics of Thermal Parameters and Some Physical Properties of Mineral Eutectic Type: Petalite-Alkali Feldspars.

The aim of the research was to check whether the system of three fluxes based on lithium aluminium silicate and alkali feldspars has a eutectic point, i.e., with the lowest melting temperature. Lithium was introduced into the mixtures in the form of petalite, which occurs naturally in nature (Bikita Zimbabwe deposit). Using naturally occurring raw materials such as petalite, sodium feldspar, and potassium feldspar, an attempt was made to obtain eutectics with the lowest melting point to facilitate thermal processing of the mineral materials. In addition, the high-temperature viscosity of the mineral alloys and physical parameters such as density, linear shrinkage, and open porosity were studied. The study showed that in these systems, there is one three-component eutectic at 1345 °C, with the lowest viscosity of 1·105 Pas and the highest density of 2.34g/cm3, with a weight content of petalite 20%, sodium feldspar 20%, and potassium feldspar 20%.

Silicate ash-resistant novel thermal barrier coatings in gas turbines

Gas turbines, used to propel aircraft or generate electricity, are vulnerable to attack by environmental silicate debris. When silicate ash is ingested into gas turbines, it melts and may adhere to the hot-section components of gas turbines (typically operating at > 1250 °C), infiltrating into their thermal barrier coatings (TBCs). These ash-related TBC issues pose a critical hazard for aircraft aviation. Here, we have developed here a novel NdYbZr2O7 coating substrate which addresses these challenges. We have quantitatively analyzed the in-situ wetting process of three representative silicate ash compositions—CMAS, volcanic ash and fly ash, and compare their infiltration behavior in the newly-developed NdYbZr2O7 coating substrate. The widely differing chemical compositions of the three ash samples yield differences in their high temperature viscosities which in turn impact their respective propensities for wetting and infiltration. CMAS exhibits the greatest dynamic wettability due to its lower viscosity over the entire range of temperature. Volcanic ash exhibits the largest infiltration depth, probably related to the relatively high solubility of rare-earth oxides (RE2O3) in volcanic ash melt. Nevertheless, compared with a traditional YSZ coating, the NdYbZr2O7 coating exhibits a better corrosion resistance in the presence of all three silicate ash samples due to the rapid precipitation of (Nd, Yb)-apatite and c-ZrO2 phases, which build a dense reaction layer, inhibiting further melt infiltration.

Study on the viscoelastic behaviour of the modified asphalt containing multi-walled carbon nanotubes (MWCNTs) and crumb rubber (CR)

Asphalt binder plays an important role on the performance of asphalt mixture, especially for the high-temperature performance. The purpose of this research is to investigate the viscoelastic behaviours of the modified asphalt containing multi-walled carbon nanotubes and crumb rubber. By adding multi-walled carbon nanotubes and crumb rubber to the base asphalt, the multi-walled carbon nanotubes modified asphalt, crumb rubber modified asphalt and multi-walled carbon nanotubes and crumb rubber composite-modified asphalt were prepared. The high-temperature viscosity and rheological property indices were obtained through the viscosity test and small amplitude oscillatory measurement. Besides, multiple stress creep recovery test and stress relaxation test were utilized to explore creep recovery behaviours and stress relaxation characteristics of the asphalt samples. Based on the time-temperature superposition principle, the master curves of complex shear modulus and phase angle were generated. Han curves of the asphalt samples were established based on superposition principle of Blotzmann. Furthermore, the Burgers model was used to model the creep-recovery data. The relaxation functions of Maxwell model and Burgers model were applied to fit stress relaxation curves of the asphalt samples. Results indicate that, the addition of multi-walled carbon nanotubes and crumb rubber caused an increase in high-temperature viscosity, and reduce the temperature susceptibility of base binder. In addition, the permanent deformation resistance, creep-recovery behaviours and stress relaxation characteristics of asphalt were enhanced remarkably by the two modifiers modification. Lastly, the composite-modified asphalt exhibited better viscoelastic behaviours than asphalt modified with either crumb rubber or multi-walled carbon nanotubes alone.

Investigation of High Temperature Performance and Viscosity Characteristics of Modified and Unmodified Color Asphalt

Investigation of High Temperature Performance and Viscosity Characteristics of Modified and Unmodified Color Asphalt