Improvement In Low-temperature Performance Research Articles

Comparative investigation of nanomaterial-enhanced asphalt binders in the UAE: a multifaceted study

ABSTRACT This study explores the impact of incorporating six distinct nanomaterials into asphalt binders to determine their effectiveness in resisting permanent deformation, fatigue and thermal cracking. Additionally, the study aimed to establish the Optimum Nano Content (ONC) for each nanomaterial to achieve the best performance against these distresses. The key findings revealed that asphalt binders with 2% Carbon Nanotubes (CNT) or Nano CuO (NCO) demonstrated the best rheological properties, partially in enhancing Elastic Recovery (ER) and rutting resistance, making them ideal for use in hot climate regions. In terms of fatigue performance, all nanomodified asphalt binders, except 2% NAT, exhibited higher fatigue life (Nf) than the control, with the NCO-nanomodified asphalt binder exhibiting the highest Nf, achieving values six to seven times greater than the control. Most nanomaterials showed no noticeable improvement in low-temperature performance, where the best performance was observed for 2% CNT and 6% Nano Iron Trioxide (NIT). For rutting resistance, the ONC for most nanomaterials was approximately 2%, whereas the ONC for fatigue resistance was typically 6%. A proposed ranking system revealed that sixteen of the nanomodified asphalt binders outperformed the control, with the 2% CNT providing the best-balanced performance, while 2% NAT was the least effective.

High titanium heavy slag powder as a sustainability filler and its influence on the performance of asphalt mortar

High titanium heavy slag powder (HSP) is a typical waste with vast reserves but lacks effective disposal. This paper investigated for the first time the potential of reusing HSP as a sustainable mineral filler for asphalt mixtures. Firstly, a comprehensive comparison and analysis of the physicochemical properties of HSP and limestone powder (LSP) were conducted. Subsequently, asphalt mortars were designed, incorporating four filler-to-asphalt ratios (F/A of 0.2, 0.3, 0.4, 0.5) and five levels of HSP substitution for LSP (0%, 25%, 50%, 75%, 100%). Finally, selected properties of twenty types of asphalt mortar were tested. Compared with LSP, the HSP presented a coarser surface, more pores, smaller particle size and larger specific surface areas, which were conducive to the formation of more “structured asphalt”. Moreover, the chemical composition of HSP was complex, but it did not leach toxic elements, and the volume stability, high temperature stability, radioactivity met the requirements. However, its alkalinity was significantly lower than that of LSP, indicating weaker interactions with the asphalt. At F/A ratios of 0.2 and 0.3, the replacement of LSP with HSP resulted in a slight decrease in high temperature properties of asphalt mortars, but an improvement in low temperature performance. However, a further increase in the F/A ratio revealed an opposite trend. The properties of asphalt mortars were influenced by the combined effects of the chemical composition and physical properties of HSP. The FTIR test results indicated that no new functional groups were formed between the HSP and asphalt, suggesting primarily physical interactions.

Improved low-temperature performance of surface modified lithium-rich Li1.2Ni0.13Co0.13Mn0.54O2 cathode materials for lithium ion batteries

High capacity lithium-rich layered oxide Li1.2Ni0.13Co0.13Mn0.54O2 cathode material is considered as a most promising cathode material for lithium ion batteries. However, its application is greatly limited due to the characteristics of low initial coulombic efficiency and poor low-temperature performance. In this study, AlF3-coated Li1.2Ni0.13Co0.13Mn0.54O2 has been prepared via a facile wet chemical process. It is found that a dense AlF3 layer with a nanoscale thickness is covered on the surface of Li1.2Ni0.13Co0.13Mn0.54O2 particles, building a rapid lithium transport bridge for adjacent active materials and reducing side reaction between the electrolyte and active material. Compared to the pristine Li1.2Ni0.13Co0.13Mn0.54O2, 2% AlF3-coated sample exhibits higher discharge capacity and initial coulombic efficiency (86.7%). Meanwhile, 2% AlF3-coated sample displays obviously superior rate capability at 0 °C and higher capacity retention at −10 and −20 °C. The improvement of low-temperature performance can reasonably be attributed to the formation of the spinel structure and the LiAlO2 on the surface of the active materials, which can improve the electronic conductivity and lithium ion conductivity of the cathode material, respectively.

Understanding Improvements to Low-Temperature Rheology of Stiff Binders Modified with Epoxidized Plant–Derived Oil Materials through Analytical Chemistry

Abstract Through recent work at Iowa State University, great potential was seen from epoxidized plant oil materials, epoxidized benzyl soyate (EBS), and epoxidized methyl soyate (EMS) as fluxes/rejuvenators. This work found that improvement in low-temperature performance was greater than improvement in high-temperature performance for solvent de-asphalting (SDA) and residuum oil super critical extraction (ROSE) unit bottoms when using either EBS or EMS as compared to results from modified vacuum distillation tower bottoms with EBS and EMS. Based on these results, analytical chemistry was done using Fourier transformed infrared with attenuated total reflection and ion mobility mass spectrometry (IM-MS) equipment. Chemical analysis showed that there is indeed something in the SDA and ROSE binders that is interacting with both EBS and EMS, making them perform aggressively. The region of interest was identified from IM-MS to be between m/z 250 and m/z 400 for the SDA and ROSE binders, of which there were 35 common components where 29 of them had similar abundances in the SDA and ROSE binders.

Remarkable improvement in low temperature performance of model three-way catalysts through solution atomic layer deposition

The development of three-way catalysts with improved low temperature activity is essential for automotive catalysis. Here, we show that solution atomic layer deposition (SALD) of titania or zirconia promoters on alumina supports lowers the light-off temperatures of rhodium-based catalysts by 50–150 °C compared to a commercial benchmark three-way catalyst. X-ray diffraction, scanning transmission electron microscopy–electron energy loss spectroscopy, diffuse reflectance UV–visible spectroscopy and X-ray absorption near edge structure results indicate that titania incorporated by SALD at one monolayer loading is present primarily as atomically disperse 5-coordinate Ti4+ species. These species persist after exposure to steam and corrosive gases at temperatures up to 960 °C. Zirconia incorporated onto alumina by SALD is present as few-nanometre oxide particles and supports a three-way catalyst activity that is superior to that of Rh on either alumina or zirconia. Our results show that molecularly precise synthesis can lead to robust promotion of precious metal activity and provide a promising path towards reducing emissions from gasoline vehicles. Improving the performance of commercial three-way catalysts like rhodium on alumina is a major challenge considering the limited design space allowed for such systems. Now, solution atomic layer deposition is used to incorporate titania or zirconia promoters into this catalyst, leading to remarkable improvements in its overall performance.

The performance of asphalt mixtures modified with lignin fiber and glass fiber: A review

Abstract Low temperature thermal cracking, rutting, moisture damage and fatigue cracking are popular damages that appear in the asphalt mixture. These problems occur mainly because of the growth in the number of heavy load vehicles, design and construction errors and environmental condition that reduce the quality, performance and the service life of the pavement. Several previous studies showed that using additives like fibers to modify asphalt mixtures could enhance the efficiency and boost the quality and service life of the pavement. This paper presents a review of the role of lignin and glass fiber as a modifier in bituminous mixes. To evaluate some main mixture properties, some tests such as the low temperature bending, indirect tensile strength, the wheel loading tracking, Hamburg wheel tracking, Marshall immersion, freezing-thaw splitting, third-point bending fatigue and indirect tensile fatigue are applied to analyze rutting, low temperature cracking resistance, moisture damage resistance and fatigue resistance of asphalt mixture modified with lignin or glass fiber. Results denoted that the quality of asphalt mixture enhanced significantly by adding lignin fiber or glass fiber. Previous researches demonstrated an obvious improvement in low temperature performance in the pavement when adding 0.2–0.4% lignin fiber of asphalt mixtures, with a limited improvement of high temperature performance. On the contrary, the asphalt mixtures modified with 0.2–0.6% glass fiber of asphalt mixtures significantly improved the resistance of high temperature. So it is hard to improve all the performances of the mixture by using only a single admixture at the same time. Thus, a new way of modifying asphalt mixture that is called double-mixture technology or composite modification, which is able to enhance the overall properties of asphalt mixture.

Electrochemical Characterization of the Lithium-Ion Cells Assembled with Ester-Based Electrolyte at Low Temperature

Lithium-ion batteries (LIBs) have become promising power sources in the field of electric vehicles (EVs) and energy storage systems (ESS) due to their high energy density and long cycle life. However, poor performance of LIBs at low temperature limits their applications, and it is thus essential to improve the low temperature cycling performance. The main requirements of liquid electrolyte for LIBs are high ion conductivity, low viscosity, wide potential window and wide liquid range. One of the most important factors for improving low temperature performance of LIBs is extension of liquid phase range, which can be affected by freezing point of organic solvent. However, it is well known that carbonate-based solvents commonly used in current LIBs exhibit poor ion conductivity and low diffusivity of lithium ion in the electrode at low temperature. A lot of approaches such as using additives to form stable SEI layer and introducing co-solvent to modify electrolyte properties have been adopted to improve cell performance at low temperature. In this study, we propose ester-based solvents to improve low temperature performance of LIBs, which exhibit stable and good cycle performance at low temperature. Analysis techniques such as electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) have been implemented to understand the improvement of low temperature performance of LIBs.

Analysis of spray dynamics of urea–water-solution jets in a SCR-DeNOx system: An LES based study

Among various advanced emission control technologies used to reduce NOx emission from diesel engines, the selective catalytic reduction (SCR) technique has proven to be more efficient. However, it is still facing the improvement of low temperature performance and the avoidance of urea deposit formation due to complex spray–wall interaction process.To gain more deep understanding of these processes, a spray module is developed for the first time within a full LES framework based on an Eulerian–Lagrangian approach. It includes especially (1) a primary and a secondary breakup model along with an advanced collision model, both to account for the atomization generated close to the nozzle exit by the multi-hole circular orifice injector used and (2) a multi-component droplet evaporation model along with a two-way coupling between the carrier gaseous phase and the droplet liquid phase throughout the dilute spray region.The suggested model is applied to evaluate the dynamics of the multi-component droplets spray resulting from an adBlue injection into a hot gas cross flow inside a channel mimicking a SCR-DeNOx flow system. First, an assessment of the multi-component droplet evaporation under hot stagnant gas environment is made. Second, the results of the adBlue spray/gas phase cross flow interaction are reported in terms of comparison between experimental data (spray structure, spray angle and penetration depth, droplet size distribution and velocity) with numerical simulations. It turns out that the model designed is able to capture in a satisfactory way the spray properties in a SCR like system.

Improvement of low-temperature performance by adopting polydimethylsiloxane-g-polyacrylate and lithium-modified silica nanosalt as electrolyte additives in lithium-ion batteries

In this work, poly[dimethylsiloxane-co-(siloxane-g-acrylate)] (PDMS-A) and lithium-modified silica nanosalt (Li202) are used together as low-temperature electrolyte additives in lithium-ion batteries (LIBs), taking advantage of the electrochemical and interfacial stabilities due to their surface functional groups. Using these additives together improves the electrochemical stability and ionic conductivity of liquid electrolyte solution to over 5.5V and 4×10−4Scm−1 at −20°C, respectively. The room-temperature electrochemical performance of a conventional LIB (LiCoO2/graphite) is improved by the addition (e.g., initial discharge capacity of 95.9mAhg−1 obtained after charging at 1.0 C-rate and consequent discharging at 5.0 C-rate). The low-temperature performance is also enhanced, achieving a capacity retention ratio of 63.4% after 50 cycles at −20°C, compared to 38.7% without the additives. It is also notable that the PDMS unit commonly existing in both additives may be the main cause of the synergistic effects on the electrochemical performance due to the compatibility between PDMS-A and Li202.

Infrared spectra and rheological properties of asphalt cement containing waste engine oil residues

This paper presents a study in which the engineering properties of asphalt binder containing waste engine oil residues were evaluated through laboratory performance testing. The infrared spectra and rheological properties of asphalt binder were evaluated with Fourier transform infrared (FT-IR) spectroscopy and dynamic shear rheometer (DSR). Asphalt binder specimens containing different concentrations of waste engine oil were fabricated with two types of binder, PG64-22 and PG76-22, and were blended with two types of laboratory aged binders to simulate the inclusion of reclaimed asphalt pavements (RAP). The results from this laboratory study indicated that the inclusion of waste engine oil up to 5% significantly altered the infrared spectra and rheological properties of asphalt binder, which may lead to the improvement of low temperature performance, but would also compromise many other performance indices, such as rut resistance at high temperature, certain aspects of fatigue resistance and elastic recovery of the binder.

Improvement in −40 °C electrochemical properties of AB2 metal hydride alloy by silicon incorporation

The ultra-low temperature (−40°C) charge transferred resistance of a Laves phase based-AB2 metal hydride alloy was reduced by a factor of 5 by a partial substitution of Ni with Si in Ti12Zr21.5V10Cr7.5Mn8.1Co8.0Ni32.2−xSixSn0.3Al0.4, where x=0–4. This improvement was due to the increases in surface area from the higher leaching-rate of the oxidation product of Si and to the surface catalytic effect with the incorporation of Si. The microstructure, gaseous phase hydrogen storage, and electrochemical properties of these alloys were investigated and reported. With the addition of Si in the formula, the abundances of both C15 and TiNi minor phases increased, which resulted in decreases in both maximum gaseous phase hydrogen storage and electrochemical capacities. Some changes on the chemical compositions of the minor phases from the Si-incorporation were observed but cannot be correlated to the improvement in low-temperature performance. These changes are the transition from Zr to ZrO2, the decrease in Ti/Zr ratio in the TiNi phase, and the higher Sn-content in the TiNi phase. An amount of 1at.% of Si is recommended from the balance among capacity, bulk diffusion, surface area, and catalytic properties of the alloys. In addition, a special sample preparation method for using inductively coupled plasma analysis to determine the Si-content in the sample was developed and presented.

Modeling Species Inhibition and Competitive Adsorption in Urea-SCR Catalysts

Although the urea-SCR technology exhibits high NOx reduction efficiency over a wide range of temperatures among the lean NOx reduction technologies, further improvement in low-temperature performance is required to meet the future emission standards and to lower the system cost. In order to improve the catalyst technologies and optimize the system performance, it is critical to understand the reaction mechanisms and catalyst behaviors with respect to operating conditions. Urea-SCR catalysts exhibit poor NOx reduction performance at low temperature operating conditions (T < 150 C). We postulate that the poor performance is either due to NH3 storage inhibition by species like hydrocarbons or due to competitive adsorption between NH3 and other adsorbates such as H2O and hydrocarbons in the exhaust stream. In this paper we attempt to develop one-dimensional models to characterize inhibition and competitive adsorption in Fe-zeolite based urea-SCR catalysts based on bench reactor experiments. We further use the competitive adsorption (CA) model to develop a standard SCR model based on previously identified kinetics. Simulation results indicate that the CA model predicts catalyst outlet NO and NH3 concentrations with minimal root mean square error.

Impact of Different Types of Modification on Low-Temperature Tensile Strength and Tcritical of Asphalt Binders

The introduction of the Superpave®asphalt binder specification provided the asphalt industry with a useful guideline for choosing appropriate materials to meet the requirements of a specific climate. Acid, alkaline, and polymer modification are just some of the ways to modify asphalt to meet the Superpave specification. The direct tension test (DTT) technique was applied to study the low-temperature properties of modified asphalt in terms of DTT failure stress values and the critical cracking temperature ( Tcritical). The bending beam rheometer (BBR) usually failed to detect improvement in low-temperature performance in polymer-modified asphalt (PMA). DTT results show that elastomeric polymer modification improves the low-temperature performance of PMA. In some PMAs, the failure stress value was higher than 9.5 MPa. The DTT technique for PMA was also reviewed. The effect of acid and alkaline modifiers on asphalt materials was studied. Acid or alkaline modification of asphalt was found to be only temporary and to be reversible. Acid modification of asphalt can be reversed by reaction with alkaline materials such as lime or antistripping agents. Alkaline modification of asphalt can be reversed by reaction with acidic materials such as carbon dioxide. Alkaline also can be washed away by water. Even though the BBR suggested a slight improvement in the low-temperature performance in acid- or alkalinemodified asphalt, the DTT failure stress values and Tcritical did not confirm this improvement. A relatively simple procedure that allows detection of acid or alkaline modification of asphalt materials is described.

Thermal Physiology, Phenology, and Distribution of Tree Frogs

Seasonal and latitudinal gradients in the thermal sensitivity of jumping performance have been examined in 10 species of hylids representing five different seasonal and distributional categories. Among temperate species, low-temperature performance is best in early-breeding northern species, intermediate in later-breeding northern species, and worst in southern species. Subtropical and tropical species have progressively higher critical thermal minima, but their thermal performance curves are not much different from those of southern temperate species in other respects. Critical upper thermal limits on jumping performance are much less variable than are lower limits, and the critical thermal minimum (CTmin) is not correlated with the critical thermal maximum (CTmax) in our sample. Effectively, CTmax is relatively inflexible, and consequently an improvement in low-temperature performance (reduction in L80, the lowest temperature at which frogs can attain 80% of maximal performance) results in a widening of...