Search Results (26)

The dynamic characteristics of liquid with high viscosity impact on stagnant packing are investigated by a computational fluid dynamics (CFD) method. The three-dimensional model, employing the volume-of-fluid (VOF) approach, simulates the evolution of liquid profiles and describes four interaction stages—approaching, encapsulation, uncovering, and detachment—between the liquid and the packings, including Raschig rings, Pall rings, and Cascade mini rings. Based on the analysis of liquid dynamic behavior, the effects of packing type, packing size, and liquid viscosity on the liquid holding volume, film area, and surface renewal rate of highly viscous fluid in packing are analyzed. Furthermore, a correlation is developed to predict the specific area of liquid in terms of dimensionless numbers. This work provides a fundamental reference for realizing the interfacial characteristics in packed columns involving highly viscous fluids. Full article

Performing infiltration experiments on sieved and repacked soil columns seems a generally underrated topic from a methodological point of view. This study assessed how the descriptive parameters of the infiltration process were influenced by (i) the operator; (ii) the number of replicated runs; and (iii) the soil sample preparation method. A total of 135 loam soil columns, each 20 cm high were prepared by two operators. Four packing methods, differing by the number of steps required to prepare the sample, were applied. One-dimensional infiltration runs were carried out on each soil column using a Mini-Disk Infiltrometer set at a pressure head of −3 cm. A statistical, or at least practical, similarity of the infiltration parameters obtained by the two operators was detected. Six replicated runs were found to be enough to obtain an acceptable description of the entire infiltration process. Differences between the packing methods were noticeable since infiltration parameters differed by up to 2.7 times, probably because soil compaction energy varied with the applied packing method. Two operators can achieve consistent and reproducible results using the same equipment and packing method since the number of steps in which the soil column is prepared has an appreciable effect on its hydrodynamic response. Full article

Lithium ion (Li-ion) battery packs have become the most popular option for powering electric vehicles (EVs). However, they have certain drawbacks, such as high temperatures and potential safety concerns as a result of chemical reactions that occur during their charging and discharging processes. These can cause thermal runaway and sudden deterioration, and therefore, efficient thermal management systems are essential to boost battery life span and overall performance. An electrochemical-thermal (ECT) model for Li-ion batteries and a conjugate heat transfer model for three-dimensional (3D) fluid flow and heat transfer are developed using COMSOL Multiphysics^®. These are used within a novel computational fluid dynamics (CFD)-enabled multi-objective optimization approach, which is used to explore the effect of the mini-channel cold plates’ geometrical parameters on key performance metrics (battery maximum temperature ($T_{max}$), pressure drop ($∆P$), and temperature standard deviation ($T_{\sigma }$)). The performance of two machine learning (ML) surrogate methods, radial basis functions (RBFs) and Gaussian process (GP), is compared. The results indicate that the GP ML approach is the most effective. Global minima for the maximum temperature, temperature standard deviation, and pressure drop ($T_{max}$, $T_{\sigma }$, and $∆P$, respectively) are identified using single objective optimization. The third version of the generalized differential evaluation (GDE3) algorithm is then used along with the GP surrogate models to perform multi-objective design optimization (MODO). Pareto fronts are generated to demonstrate the potential trade-offs between $T_{max}$, $T_{\sigma }$, and $∆P$. The obtained optimization results show that the maximum temperature dropped from 36.38 to 35.98 °C, the pressure drop dramatically decreased from 782.82 to 487.16 Pa, and the temperature standard deviation decreased from 2.14 to 2.12 K; the corresponding optimum design parameters are the channel width of 8 mm and the horizontal spacing near the cold plate margin of 5 mm. Full article

Self-compacting concrete (SCC), known for its excellent fluidity and self-compacting ability, is widely used in civil engineering. To enhance the comprehensive performance of SCC, dolomite powder (DP) is integrated as a substitute for cement. This study aims to analyze the impact of DP on the yield stress relationship between self-compacting mortar (SCM) and self-compacting paste (SCP) from a multi-scale perspective. A new predictive model for the yield stress relationship between SCM and SCP incorporating DP is established by improving the $n$ value in the existing ${\varphi }_{\mathrm{e}}$ model, which characterizes the sensitivity of the mortar yield stress relative to changes in the paste yield stress. By conducting mini-slump flow tests on nine sets of cement–DP mixtures, it is found that DP impacts the yield stress relationship between SCM and SCP mainly through changes in the inter-particle filling effect, and the $n$ value in the predictive model is roughly between 2.4 and 3.6. When the DP content is kept constant and the particle size is changed, the $n$ value shows a strong positive linear relationship with the packing density of the paste (${\varphi }_{\mathrm{e},\mathrm{p}}$). The relationship between $n$ and ${\varphi }_{\mathrm{e},\mathrm{p}}$ is derived using the linear fitting method, which improves the model’s predictive accuracy by 95.2%. Full article

Radar observation is an effective way to understand subsurface structures in terms of the dielectric constant, whose controlling factors include chemical composition, packing density, and water/ice content. Recently, laboratory measurements have shown that the dielectric constant of lunar regolith simulants also depends on the temperature, which has never been evaluated from remote sensing data. In this study, we estimated the dielectric constant from the Miniature Radio Frequency (Mini-RF) data on a lunar crater floor in the north polar region at two different local times (i.e., different surface temperatures). We calculated the dielectric constant using the inversion method and obtained the bolometric surface temperature from the Diviner Lunar Radiometer Experiment (Diviner) data. The histograms of the estimated dielectric constant values are different between the two local times. This could be interpreted as a result of the temperature dependence of the dielectric constant, while further evaluation of the influence of topography on the incidence angle and small surface roughness is needed. Nevertheless, our result suggests that the temperature dependence of the dielectric constant should be considered when interpreting S-band radar observations of the Moon and other celestial bodies with large surface temperature differences. Full article

Textile dyes widely used in industrial products are known as a major threat to human health and water ecological security. On the other hand, sol gel represents a principal driver of the adoption of dispersive solid-phase microextractors (d-µ SPME) for pollutants residues in water. Thus, the current study reports a new and highly rapid and highly efficient hybrid sol-gel-based sponge polyurethane foam as a dispersive solid-phase microextractor (d-µ-SPME) platform packed mini-column for complete preconcentration and subsequent spectrophotometric detection of eosin Y textile dye in wastewater. The unique porous structure of the prepared sol-gel immobilized polyurethane foams (sol-gel/PUF) has suggested its use for the complete removal of eosin Y dye (EY) from water. In the mini-column, the number (N) of plates, the height equivalent to the theoretical plates (HETP), the critical capacity (CC), and the breakthrough capacities (BC) of the hybrid sol-gel-treated polyurethane foams towards EY dye were determined via the breakthrough capacity curve at various flow rates. Under the optimum condition using the matrix match strategy, the linear range of 0.01–5 µg L⁻¹, LODs and LOQs in the range of 0.006 µg L⁻¹, and 0.01 µg L⁻¹ for wastewater were achieved. The intra-day and inter-day precisions were evaluated at two different concentration levels (0.05 and 5 μg L⁻¹ of dye) on the same day and five distinct days, respectively. The analytical utility of the absorbents packed in pulses and mini-columns to extract and recover EY dye was attained by 98.94%. The column could efficiently remove different dyes from real industrial effluents, and hence the sol-gel/PUF is a good competitor for commercial applications. The findings of this research work have strong potential in the future to be used in selecting the most suitable lightweight growing medium for a green roof based on stakeholder requirements. Therefore, this study has provided a convenient pathway for the preparation of compressible and reusable sponge materials from renewable biomass for efficient removal of EY from the water environment. Full article

The purpose of this study was to compare the effects of nutritional supplement drinks (NSDs) and nutritional education (NE) on the nutritional status and physical performance of older nursing home residents who were at risk of malnutrition. This study was a clustered, randomized, parallel, multi-center clinical trial, with 107 participants more than 65 years old and at risk of malnutrition recruited from several nursing homes in this study. Participants were divided into two groups: an NE group (n = 50) and an NSD group (n = 57). The NE group was given NE by a dietitian, while the NSD group was provided with two packs of NSD except receiving NE (Mei Balance, Meiji Holdings, Tokyo, Japan) per day as a snack between meals and before bed. Anthropometric data, blood pressure, nutritional status, blood biochemical biomarkers, and physical performance were measured before and after 12-week interventions. After 12 weeks of NE combined with NSD intervention, body weight, body-mass index, the mini nutritional assessment-short form (MNA-SF) score, walking speed, and SF-36 questionnaire score were improved in older nursing home residents at risk of malnutrition. Full article

Recently, the increased adoption of electric vehicles (EVs) has significantly demanded new energy storage systems (ESS) technologies. In this way, Lithium-ion batteries (LIB) are the mainstream technology for this application. Lithium presents several advantages compared with other chemicals because it can provide delivery energy for a long time, a long lifetime, and high density and capacity. The LIB comprises several cells connected in different configurations, such as parallel, series, or combinations. This variety of designs makes the monitoring control process more complex, complicating diagnosing and prognosis of abuses and failures. To observe these difficulties, this paper presents sixteen experiments of a mini-packing of four cells under the main abuses found in the LIB. The time series data were collected during the abuses and saved in a CSV file. The results indicated that the current, temperature, and voltage should be used to identify the external short-circuit (ESC) failures in the packing of batteries. On the other side, only the voltage signature is able to determine the Over-Charging (OC), and finally, the combination of temperature and voltage should be used to identify and locate the Over-Discharging (OD) failures in different arrangements of packing. This study also provides ways to build mechanisms to protect the cells and avoid loss of performance and safety issues. Full article

It is important to consider the thermal management of lithium-ion batteries to overcome their limitations in usage and improve their performance and life cycles. In this study, a novel cooling system for the thermal management of lithium-ion battery packs is proposed by using an inner cylinder in the cooling channel and different-shaped nanoparticles in the base fluid, which is used as the cooling medium. The performance improvements in a 20 Ah capacity battery are compared by using a water–boehmite alumina (AlOOH) nanofluid, considering cylinder-, brick-, and blade-shaped nanoparticles up to a solid volume fraction of 2%. The numerical analysis is conducted using the finite element method, and Reynolds numbers between 100 and 600 are considered. When the efficacy of the coolants utilized is compared, it is apparent that as the Reynolds number increases, both cooling media decrease the highest temperature and homogenize the temperatures in the battery. The utilization of the cylinder in the mini-channel results in a 2 °C temperature drop at Re = 600 as compared to the flat channel. A boehmite alumina nanofluid with a 2% volume fraction reduces the maximum temperature by 5.1% at Re = 200. When the shape effect of the nanofluid is examined, it is noted that the cylinder-shaped particle improves the temperature by 4.93% as compared to blade-shaped nanoparticles and 7.32% as compared to brick-shaped nanoparticles. Thus, the combined utilization of a nanofluid containing cylindrical-shaped nanoparticles as the cooling medium and a cylinder in the mini-channel of a battery thermal management system provides an effective cooling system for the thermal management of the battery pack. The outcomes of this work are helpful for further system design and optimization studies related to battery thermal management. Full article

Battery Electric Vehicles (BEVs) have an increasingly large share of the vehicle market. To ensure a safe and long operation of the mostly large underfloor-mounted traction batteries, they must be developed and tested in advance under realistic conditions. Current standards often do not provide sufficiently realistic requirements for environmental and lifetime testing, as these are mostly based on data measured on cars with an Internal Combustion Engine (ICE). Prior to this work, vibration measurements were performed on two battery-powered electric vehicles and a battery-powered commercial mini truck over various road surfaces and other influences. The measurement data are statistically evaluated so that a statement can be made about the influence of various parameters on the vibrations measured at the battery pack housing and the scatter of the influencing parameters. By creating a load profile based on the existing measurement data, current standards can be questioned and new insights gained in the development of a vibration profile for the realistic testing of battery packs for BEVs. Full article

Nitrites are metastable anions that are derived from the oxidation of ammonia by agricultural pollution, sewage, decaying protein, and other nitrogen sources. They are a recognized environmental issue due to their role in eutrophication, as well as in surface and groundwater contamination, being toxic to almost all living creatures. Recently, we reported on the high efficiency of two cationic resins (R1 and R2) forming hydrogels (R1HG and R2HG) by dispersion in water in removing anionic dyes from water by electrostatic binding. Here, aiming at developing adsorbent materials for nitrite remediation, R1, R2, R1HG, and R2HG were first tested in adsorption experiments in batches monitored by UV–Vis methods, using the Griess reagent system (GRS) in order to assess their removal efficiency by contact over time. Particularly, samples of water appositely contaminated with nitrites were analyzed by UV–Vis before and during treatment with the hydrogels. The initial concentration of nitrites was quantified (118 mg/L). Then, the removal of nitrites over time, the removal efficiency of R1HG (89.2%) and of R2HG (89.6%), their maximum adsorption (21.0 mg/g and 23.5 mg/g), as well as the adsorption kinetics and mechanisms were evaluated. Additionally, R1HG- and R2HG-based columns (h = 8–10 cm, Ø_E = 2 cm) mimicking mini-scale decontamination systems by filtration were used to rapidly filter samples of water polluted with nitrite that were under pressure. R1HG and R2GH were capable of totally removing nitrites (99.5% and 100%) from volumes of nitrite solutions that were 118 mg/L that is 10 times the volumes of resins used. Additionally, when extending filtration to increasing volumes of the same nitrite solution up to 60 times the volume of resins used, the removal efficiently of R1HG decreased, and that of R2HG remained stable at over 89%. Interestingly, both the worn-out hydrogels were regenerable by 1% HCl washing, without a significant reduction in their original efficiency. There is a lack of studies in the literature reporting on novel methods to remove nitrite from water. R1HG and especially R2HG represent low-cost, up-scalable, and regenerable column-packing materials with promise for applications in the treatment of drinking water contaminated by nitrites. Full article

For years, researchers have focused on the determination of metal ions at trace levels in environmental and food samples using analytical methods that employ techniques with low cost acquisition and maintenance and without microwave-assisted acid digestion procedures or aggressive reagents. Therefore, the present study deals with the synthesis and application of a novel, restricted-access poly(protoporphyrin-co-vinyl pyridine) adsorbent to preconcentrate copper in water samples and bovine milk that have only been subjected to pH adjusting (pH 6.0) and filtration using posterior on-line determination by FAAS. Regarding macromolecules, the restricted-access property of the adsorbent was achieved using the hydrophilic compound 2-hydroxyethyl methacrylate (HEMA). This method is based on the preconcentration of Cu²⁺ ions using a flow-injection system which is buffered with 0.05 mol L⁻¹ of Britton–Robinson (BR) at a pH of 6.0 and has a flow rate of 14.0 mL min⁻¹ through a mini-column packed with 50.0 mg of adsorbent. The elution was carried out using 0.40 mol L⁻¹ of HCl toward the FAAS detector. The developed method provided a preconcentration factor of 44.7-fold, low limits of detection (LOD) (0.90 µg L⁻¹) and quantification (LOQ) (2.90 µg L⁻¹), tolerance to interfering ions (95.0 and 103.0%), and intra-day and inter-day precision assessed as the RSD (percentage of relative standard deviation), which ranged from 3.08 to 4.80%. The restricted-access poly(protoporphyrin-co-vinyl pyridine) adsorbent demonstrated outstanding features to exclude macromolecules, bovine serum albumin (BSA), and humic acid (HA) from an aqueous medium. Lake water and bovine milk samples were analyzed by the proposed preconcentration method with minimal sample pretreatment (which was based mainly on pH adjusting and filtration using an analytical curve with external calibration), yielding recovery values from addition and recovery tests ranging from 91.7 to 101.9%. The developed method shows great advantages over previously published methods, avoiding the time-consuming use of concentrated acids in a microwave-assisted acid digestion procedure. Full article

Lithium batteries in the electric vehicles (EVs) reveal that the operating temperature and temperature uniformity within the battery pack significantly affect its performance. An efficient thermal management system is urgently needed to protect the battery module within suitable temperature range. In this study, the composite silica gel (CSG), coupled with cross-structure mini-channel cold plate (MCP) as the cooling system, has been proposed and applied in a battery module, which can provide a reliable method of controlling battery temperature with low energy consumption. The experimental and simulation results reveal that a composite silica gel-based liquid system can control the temperature below 45 °C and maintain the temperature difference within 2 °C at a 3C discharge rate. Besides, the CSG, coupled with the structure of reciprocal chiasma channels for the battery module, presents an optimum temperature-controlling performance among various cooling structures during the charge and discharge cycling process. This research is expected to provide significant insights into the designing and optimization of thermal management systems. Full article

Background: Small cigarette pack sizes contain less than 20 cigarette sticks in a pack. Smaller packs may suggest lower costs, increasing affordability among lower-income users, especially the younger generation, which could lead to tobacco-related diseases and economic costs, including human capital lost results from tobacco-attributable morbidity and mortality. This concern has caused many countries to ban the sale of single cigarette sticks or kiddie packs. However, small cigarette pack sizes were proposed recently to be reintroduced by the tobacco industry with an excuse to prevent consumers from buying illicit cigarettes. This would demean efforts in combating tobacco consumption based on the existing tobacco control policies to prevent minors from purchasing cigarettes. Given the competing influences of affordability and availability of tobacco on consumption and the dearth of evidence-based review on the impact of pack size on smoking, this systematic review was conducted to identify the link between kiddie packs and smoking specifically on the initiation of smoking, urge/tendency to buy cigarettes among the general population and attempt to reduce cigarette consumption and prevalence of smoking using kiddie packs among current smokers. Methods: We include all studies except for reviews, guidelines, conference papers, commentaries, editorials, or opinion pieces. A database search was conducted in PubMed, EMBASE, CENTRAL, Web of Science and Scopus on 27 November 2021. The results were presented in the form of narrative synthesis under four groups: initiation of smoking; urge/tendency to buy cigarettes; the prevalence of smoking, and attempt to reduce cigarette consumption. The literature search identified 1601 articles, of which 21 articles had met the inclusion criteria. The methodological quality of all included articles was determined using a validated 16-item quality assessment tool (QATSDD). The average quality score for all papers was 34.8%. Discussion: Given the diverse study settings of the articles and despite the challenges of the methodological quality of some articles, this review provides some evidence that kiddie packs may increase the urge/tendency to buy cigarettes and mixed evidence on the attempt to reduce cigarette consumption. This review also found some evidence that kiddie pack purchasing among teenage smokers was higher compared to adults. However, we are uncertain about the link between kiddie packs and smoking initiation. Nevertheless, since most studies were of low quality, further high-quality studies are needed to conclude about the impact of kiddie packs on smoking to assist the policymakers and stakeholders in formulating new policies and strengthening existing strategies related to the kiddie packs. Full article

A micro needle trap sampler (NTS) was carried by a mini quadrotor drone (Mavic Pro, DJI) to collect volatile organic compounds (VOCs) from industries. The NTS was fabricated using a 7 cm long, 22-gauge stainless steel needle by packing powdered divinylbenzene (DVB) adsorbents (60–80 mesh diameters). The telescoping sampling shaft was installed on the drone to extend the NTS beyond the downward air turbulence that was caused by the rotation of its propellers. The total mass of the sampling device, including an NTS, a telescoping shaft, a mini-air pump, and an ABS (acrylonitrile butadiene styrene) rack, was not more than 200 g. The emitted VOCs, those from a steel processing plant, including aromatic hydrocarbons (toluene of 15 ppb, ethylbenzene of 9 ppb and p-xylene 12 ppb), and those from a semiconductor processing factory, including trace amounts of methanol (1.96–2.00 ppm), acetone (0.05–0.10 ppm), and toluene (1.04–2.00 ppm), were extracted by the NTS on the drone and identified using a gas chromatography-mass spectroscopy (GC-MS) system in the laboratory. According to the results of VOC detection during the sampling flight of a drone, the stationary pollution sources were successfully identified. Full article