Loading Density Research Articles

Assessment of malaria parasitemia in people living with HIV/AIDS in Kumba, Cameroon

Background: Malaria parasitemia and HIV infections are globally important public health concerns. People residing in regions where these two infections are endemic are prone to develop co-infection. Sub-Saharan Africa has the greatest burden of both diseases and Cameroon particularly the South West Region has been reported as one of the regions with the highest malaria and HIV prevalence. Hence, there is a need for continuous monitoring and epidemiologic inquiry to generate updated data on the burden of malaria parasitemia on HIV/AIDS. The aim of this study was to determine the prevalence of malaria parasitemia and the association between viral load and malaria parasite density in people living with HIV/AIDS in Kumba, Cameroon. Methods: A cross-sectional study was conducted involving 250 people living with HIV/AIDS selected from five main Community Based Organizations in Kumba during a period of 5 months from April to August 2021. Participants’ consent was obtained followed by socio-demographic and other useful data via a standardized questionnaire. Capillary blood samples were collected and Giemsa-stained blood films were examined to detect malaria parasitemia. The recent viral loads were collected from the participants’ medical files. Pearson’s chi-square was used for the comparison of proportions and correlation analysis to determine the association between parasite density and viral load. Statistical significance was set at p < 0.05. Results: An overall prevalence of malaria parasitemia in people living with HIV/AIDS in Kumba was 27.2%; [95% CI: 21.8% – 33.2%]. Among 215 participants who were HAART-experienced, 49(22.79%); [95% CI: 17.6% – 27.9%] were found to be positive for malaria parasitemia while 19(54.29%); [95% CI: 48.1% – 60.5%] out of the 35 HAART naïve individuals were positive for malaria parasitemia. This difference in prevalence was statistically significant (X2 = 15.078, df = 1, N = 250, p < 0.000). Also, malaria parasite density was significantly dependent on viral load (X2 = 61.065, df = 6, N = 49, p < 0.000). HAART-experienced participants with high viral load(>1000copies/ml) had significantly higher malaria parasite density(>400trophozoites/µL) than HAART-experienced participants with ‘not detectable’ viral load. Conclusion: The prevalence of malaria parasitemia in the study population was 27.2%. HAART naïve individuals had significantly higher malaria parasitemia prevalence and malaria parasite density than HAART-experienced individuals. Malaria parasite density was significantly dependent on viral load in HAART-experienced individuals.

β-Glucosidase Immobilized on Magnetic Nanoparticles: Controlling Biomolecule Footprint and Particle Functional Group Density to Navigate the Activity-Stability Tradeoff.

In the present work, the immobilized footprint of β-glucosidase (BGL) on silica-coated iron oxide was explored to produce reusable catalysts with flexible active sites for high activity and heightened storage stability. Synthesized iron oxide particles were coated with silica and functionalized with various densities of (3-aminopropyl)triethoxysilane (APTES) to obtain particles with amine densities ranging from 0 to 3 × 10-5 mol/g particle. The amine-modified particles were activated with glutaraldehyde, and subsequently, BGL was immobilized using either a 0.1 or 1 mg/mL enzyme solution to produce biomolecules with a large or small footprint on the particle surface. The initial activity, activity for subsequent hydrolysis cycles, activity after extended storage, and biomolecule footprint were studied as a function of APTES density and concentration of enzyme used for immobilization. At high immobilization amounts, the specific activity and footprint were reduced, but the immobilized biomolecules were stable during storage. However, at low enzyme immobilizations, the activity of the enzymes was retained, the immobilized enzymes adopted large footprints, and the storage stability increased with APTES density relative to the free enzyme. These results highlight how controlling both the protein load and functional group density can yield immobilized enzymes possessing high activity, which are stable during storage.

Synthesis of new type of nonlinear optical chromophores: The introduction of a novel aromatic amine donor 1-oxajulolidine to enhance the electro-optical activity of organic second-order nonlinear optical materials

Developing new organic second-order nonlinear optical chromophores with a new electron donor is crucial for enhancing performance of electro-optic (EO) materials. A series of new second-order nonlinear optical chromophores (J1, JS and JO) with new electron donor 1-Oxajulolidine have been designed and synthesized. Ref1, Ref2 and Ref3 with N, N-diethylaniline (DEA), 4-anisole and julolidine as electron donor had also been synthesized for comparison. The result of TGA and DSC tests suggested that the decomposition temperature of the chromophores was higher than 260 °C. As the UV–vis absorption spectra of chromophores in solution, maximum absorption (λmax) of the chromophores J1 with 1-Oxajulolidine group presented red-shift compared to Ref1 and Ref2, but blue-shift to Ref3. Nevertheless, chromophore with 1-Oxajulolidine presented more obvious solvatochromic behavior from dioxane to dichloromethane. Density functional theory had been used to calculate HOMO-LUMO energy gaps and β of these chromophores. The r33 values of guest-host EO polymers Ref1/APC, J1/APC, JS/APC and JO/APC with a loading density of 10 wt% were obtained as 7.5, 9.6, 15.3 and 13.5 pm V−1, respectively. The above result clearly indicated that r33 of J1/APC (9.6 pm V−1) was 27% higher than that of Ref1/APC (7.5 pm V−1). The electro-optic coefficient of JS with the same conjugate bridge and acceptor was higher than that of FTC in the same doping concentration. As revealed by the above results, the introduction of the polycyclic structure of 1-Oxajulolidine, containing two electron-rich atoms (N and O), could efficiently enhance the electro-optical performance. Furthermore, λmax of JS in doped film showed blue-shift compared with FTC which exhibited a promising potential for tackling nonlinearity and transparency trade-off in second-order nonlinear optical (NLO) materials.

The optimization research on the coupled of active and passive energy supplying in public institutions in China

The building sector is one of the largest energy user and carbon emitters globally. To increase the utilization rate of renewable energy and reduce carbon dioxide emissions, the optimal technical scheme of active public institutions and coupled utilization of renewable energy is studied. In this study, the energy consumption of three types of public institutions in various regions of China was simulated by using DeST building energy consumption software, combined with energy conversion efficiency and data released by the National Bureau of Statistics, and the total energy demand and total energy supply of public institutions were predicted using the load density method. Based on the coupling mechanism of the MARKAL model, the optimal proportion of renewable energy in the energy supply of public buildings in different regions is determined. Through the study of the number of public institutions in various regions of China, energy consumption characteristics, construction area, and other related data, the reverse energy flow method is creatively proposed, and the active and renewable energy coupling algorithm from the energy demand side of public institutions to the energy supply side is established. The results show that the central region has the highest utilization rate of renewable energy in the public sector, reaching 36.18%. The use of renewable energy in public buildings in hot summer and warm winter zones decreased to 35.08%, and it was 12.82% in cold zones. By 2025, the proportion of renewable energy resources in China is expected to reach 29.2%. The energy coupling model and algorithm constructed in this paper can provide a basis for the coupling macro configuration of renewable energy in public institutions in China.

Dense T-Nb2O5/Carbon Microspheres for Ultrafast-(Dis)charge and High-Loading Lithium-Ion Batteries.

Orthorhombic niobium pentoxide (T-Nb2O5) is regarded as a potential anode material for lithium-ion batteries (LIBs) due to ultrafast charge/discharge and high safety. However, the poor electronic conductivity and low mass loading of nanostructured T-Nb2O5 limit its practical application in LIBs. Herein, we design and construct dense microspheres consisting of nanostructured T-Nb2O5 embedded in amorphous N-doped carbon (Nb2O5@NC) via a facile method to achieve fast ionic and electronic transport as well as a high mass loading. The dense micro-sized particles with an interconnected carbon network avoid the low mass loading and volumetric energy density of conventional nanostructures. Interconnected pores in the range of a few nanometers are also formed in the Nb2O5@NC microspheres. Notably, at a high mass loading of 12.8 mg cm-2, Nb2O5@NC can achieve a high specific capacity of 171.5 mAh g-1 and an areal capacity of 2.05 mAh cm-2, showing its high lithium storage capacity. The intercalation reaction mechanism with a small volume change during cycling at both crystal lattice and microsphere levels is confirmed by in situ X-ray diffraction and in situ high-resolution transmission electron microscopy. The elegant structure and the electrochemical reaction mechanism disclosed in the work is important for designing ultrafast-(dis)charge electrode materials.

Nitrogen-doped hollow bowl-like carbon as highly effective sensing material for electroanalysis

Hollow carbon nanosphere (HCS) has received considerable attentions in electroanalysis owing to its unique advantages in surface area, conductivity, stability and cost, while what is ignored is that the close structure with full sphere of HCS generally causes a great loss in its utility ratio of internal surface and its loading density. In this work, a novel hollow bowl-like carbon nanomaterial (HBCs) with open macropore network, nitrogen-doped HBCs (NHBCs), was designed and used as a highly effective sensing material in electroanalysis for the first time. Selecting carbendazim (CBZ), acetaminophen (ACAP) and dopamine (DA) as three representative analytes respectively from pesticides, environmental pollutants and biomolecules, the analytical performances of NHBCs modified electrode towards these analytes were evaluated. The results demonstrated that NHBCs can exhibit much better analytical performances than nitrogen doped HCS (NHCS). After optimizing various analytical conditions, NHBCs modified electrode possesses considerably low analytical limits and wide linearities towards three analytes: 2.7 nM and 0.005 to 8.0 μM for CBZ, 4.9 nM and 0.01 to 35.0 μM for ACAP, 7.6 nM and 0.05 to 125.0 μM for DA, revealing that the as-proposed HBCs-based material has great potential applications in electrochemical sensing.

Parametric investigation of sand erosion rates in gas pipeline bends under typical industry conditions using simplified method

ABSTRACT The production and transport of sand from oil and gas wells into production and transport facilities results in flow assurance and structural problems. A critical operational issue is the erosion of oil and gas facilities by the suspended sand particles, particularly around flow diversions. This study investigated the effects of four key parameters, namely particle size, sand load, fluid velocity, and fluid density, on the rate of sand erosion in gas pipeline bends using DNV GL-RPO501 and Star CCM+ software package, a Computational Fluid Dynamics (CFD) tool developed by CD – adapco. Sand concentration and particle sizes both cause a linear increase in erosion rate. The particle sizes affected the location of maximum erosion. The single and mixture component gas densities showed an inverse linear and non-uniform relationship with erosion rate. The CFD models underpredicted erosion rates by about 90% compared to the experimental data. An exponential relation exists between the erosion rate and gas/sand velocity especially velocities above 10 m/s. The CFD method largely predicted more realistic values of erosion rate than the DNV GL-RPO501 due to some oversimplified assumptions made in the latter. The CFD tool however compared favorably with the DNV GL-RPO501 at high velocities. Both CFD and DNV GL-RPO501 models are recommended for erosion studies at higher fluid velocities, while the CFD modeling is better at lower velocities by incorporating drag and inertial forces which are important forces at low gas velocities. The particle and fluid velocity affected the sand erosion rate more than the other factors considered. However, future studies should consider modeling erosion rates under transient conditions and investigate the effects of various turbulence models. Different sand mixtures with various particle sizes and other gases such as CO2 should be considered.

Development of a Framework for Modeling Protection Mechanisms Provided By Multi-Layered Organic Coatings Applied to Aerospace Al Alloys Via Finite Element Analysis

Aluminum alloys, such as AA2024 and AA7050, are widely used in aerospace applications due to their high strength-to-weight ratio. However, because of the heterogeneous microstructure of these alloys, they are susceptible to microgalvanic corrosion and pitting in chloride-containing environments. The corrosion susceptibility is further increased when these alloys are in contact with more noble alloys, such as in locations near fasteners, where the galvanic interaction leads to accelerated corrosion attack of the less noble Al alloy. To protect these structures against corrosion attack, organic coatings are commonly used. Typical coating systems are usually composed of three layers: a conversion coating, a primer, and a topcoat. When the topcoat is breached, the primer can provide active corrosion protection by the release of inhibitors embedded in the primer. Depending on the type of inhibitor, it can provide chemical protection by the formation of a passive film on the surface of the exposed metallic area and/or provide cathodic protection by the preferential dissolution of sacrificial anodes.The efficacy of the corrosion protection provided by the multilayered coating system to Al alloys in aircraft components exposed to atmospheric corrosion is affected by a large number of variables. The dynamic environment in which the component is exposed to (e.g., relative humidity, temperature, salt loading density), the geometry of the component, the chemistry of the primer, and the type of alloy are examples of important parameters that impact the corrosion and protection mechanisms. To unravel the impact of each one of these variables and/or the synergistic effects between them, a large volume of experimental work is needed, making the prediction of coating failure, corrosion damage, and, ultimately, component lifetime, remarkably challenging. In this context, the development of computational models that can simulate corrosion and corrosion protection mechanisms is attractive, as they can be used as tool to effectively assess the large parameter space and increase efficiency of experimental work.This work focuses on developing a framework for modeling the protection mechanisms offered by chromate-based and Mg-rich primers via finite element analysis. Chemical and electrochemical protection mechanisms were modeled taking into consideration leaching of inhibitor from the primer, mass transport and the impact of the inhibitors in the electrochemistry of the Al alloys. The impact of environmental, geometric, and coating parameters on the effectiveness of the protection mechanisms was assessed. Ultimately, the framework developed will provide a better understanding of protection mechanisms of the organic coating systems and serve as a framework to study new coating systems.

Magnetic/fluorescent dual-modal lateral flow immunoassay based on multifunctional nanobeads for rapid and accurate SARS-CoV-2 nucleocapsid protein detection

The SARS-CoV-2 pandemic has posed a huge challenge to rapid and accurate diagnosis of SARS-CoV-2 in the early stage of infection. In this work, we developed a novel magnetic/fluorescent dual-modal lateral flow immunoassay (LFIA) based on multifunctional nanobeads for rapid and accurate determination of SARS-CoV-2 nucleocapsid protein (NP). The multifunctional nanobeads were fabricated by using polyethyleneimine (PEI) as a mediate shell to combine superparamagnetic Fe3O4 core with dual quantum dot shells (MagDQD). The core-shell structure of MagDQD label with high loading density of quantum dots (QDs) and superior magnetic content realized LFIA with dual quantitative analysis modal from the assemblies of individual single nanoparticles. The LFIA integrated the advantages of magnetic signal and fluorescent signal, resulting excellent accuracy for quantitative analysis and high elasticity of the overall detection. In addition, magnetic signal and fluorescent signal both had high sensitivity with the limit of detection (LOD) as 0.235 ng mL−1 and 0.012 ng mL−1, respectively. The recovery rates of the methods in simulated saliva samples were 91.36%–103.60% (magnetic signal) and 94.39%–104.38% (fluorescent signal). The results indicate the method has a considerable potential to be an effective tool for diagnose SARS-CoV-2 in the early stage of infection.

Practical Model for Short-Circuit Current Calculation of Photovoltaic Power Station Based on Improved RLS Algorithm

In recent years, with the rapid economic development, the development speed of all walks of life has entered a new level, and the power industry has also developed rapidly. Driven by market demand, China’s power transmission range and power transmission capacity will enter a new level. At the same time, the problems brought about by the development of the power system are equally severe. Due to the large load density in individual areas, the detection of short-circuit current must be improved as an important issue. The purpose of this paper is to study how to improve the practical model of short-circuit current calculation of photovoltaic power plants, so that it can be well applied to the current high-density current detection in China. Therefore, this paper improves the recursive least squares (RLS) algorithm and applies it to the practical model of short-circuit current calculation of photovoltaic power plants and describes the improvement process of the algorithm in detail. At the same time, this paper designs relevant experiments and analysis to count the data of the improved RLS algorithm in the short-circuit current calculation of the actual photovoltaic power station and combines the data of this part to test and analyze the ability of the algorithm. The experimental results in this paper show that the improved RLS algorithm has a very good improvement in the calculation accuracy of the short-circuit current calculation of photovoltaic power plants in the actual model calculation. At the same time, the calculation efficiency is also improved, and the current tracking effect is also improved by 7%.

A novel method for detection of ochratoxin A in foods—Co-MOFs based dual signal ratiometric electrochemical aptamer sensor coupled with DNA walker

Ochratoxin A (OTA) is a naturally occurring mycotoxin that poses serious threats, such as kidney damage, to human health. Therefore, we developed a DNA walker-based dual-signal electrochemical ratiometric platform for OTA detection, which could overlook the variations in environmental and instrumental factors and DNA load densities. Cobalt metal–organic frameworks (Co-MOFs) and toluidine blue were used as the electrochemical signal tag and internal reference probe, respectively. In the presence of OTA, this developed machine resulted in the DNA labelled-Co-MOFs far away from the electrode. Thus, Co-MOFs signal at −1.18 V decreased, while toluidine blue at −0.28 V increased. This proposed strategy has displayed superior sensitivity (limit of detection = 0.31 fg/mL, linear range = 1–50 ng/mL) and high reproducibility. The sensor was also applied for determining OTA content in red wine samples and the results were comparable to those of commercial enzyme-linked immunoassay kits with satisfactory results.

COF-DNA Bicolor Nanoprobes for Imaging Tumor-Associated mRNAs in Living Cells

Developing probes for the simultaneous detection of multiple tumor-associated mRNAs is beneficial for the precise diagnosis and early therapy of cancer. In this work, we prepared two COF-DNA bicolor probes at room temperature and freezing conditions and evaluated their performances in simultaneous imaging of intracellular tumor-associated mRNAs. By loading dye-labeled survivin- and TK1-mRNA recognition sequences on porphyrin COF NPs, nucleic acid-specific "off-on" nanoprobes were obtained. The nanoprobe prepared by the freezing method exhibits higher ssDNA loading density and better fluorescence quenching efficiency. Moreover, its signal-to-noise ratio is significantly higher than that prepared at room temperature, and the target recognition effect was unaffected. Significantly, the freezing-method-prepared nanoprobe has higher signal intensities in target-overexpressed cells compared to the room-temperature-prepared probe, while their signals in cells with low target expression are similar. Thus, the freezing-method-prepared nanoprobe is a promising tool for improved cancer diagnostic imaging. This work can offer new insights into the exploration of high-performance COF-based nanoprobes for multiple biomarker detection.

The Effect of Material Thickness, Load Density, External Airflow, and Relative Humidity on the Drying Efficiency and Quality of EHD-Dried Apples.

Electrohydrodynamic drying is a novel non-thermal technique for dehydrating heat-sensitive foods. However, its industrial applications are limited due to the underexplored effects of material properties and environmental conditions on product quality. For this purpose, a multifactorial experiment was designed to study the effects of material thickness, load density, external airflow, and humidity on the EHD drying efficiency and quality of apple slices. The experiments show that the intensity of EHD drying increased with a decrease in humidity, slice thickness, and load density. The effective diffusivity of apple slices with EHD drying was about 5.17·10−12 m2/s, slightly increasing with external airflow. The specific energy consumption of EHD drying was 10–12 times lower than hot air drying. The time of EHD drying at 20 °C was equivalent to hot air drying at 40 °C, but the impact of EHD drying on the product quality was significantly lower. EHD drying better preserved the color and phenolic content in dried apple slices, with less cellular damage. Hence, EHD drying can be employed in industry as a sustainable alternative to hot air drying.

Influences of Loading Density of Tobacco Drying Chamber on Drying Quality

Drying is one of the most important steps in tobacco processing because it determines the color, taste, and micronutrients in tobacco. The loading density and the arrangement of tobacco leaves in the drying chamber affect the temperature and humidity distribution of the air, thereby affecting the drying quality. In this paper, three drying cases with different tobacco weights were studied by computational fluid dynamics (CFD) simulation as well as experimental. The results show that when the loading density of the tobacco drying chamber increases, the local resistance of tobacco leaves increases sharply, and the velocity difference and temperature difference of the air in the tobacco drying chamber increases. The maximum temperature difference in the highest loading density reaches 10 K. The uneven temperature distribution of the air reduces the quality of the dried tobacco.

Transferability of Airborne LiDAR Data for Canopy Fuel Mapping: Effect of Pulse Density and Model Formulation

Canopy fuel characterization is critical to assess fire hazard and potential severity in forest stands. Simulation tools provide useful information for fire prevention planning to reduce wildfire impacts, provided that reliable fuel maps exist at adequate spatial resolution. Free airborne LiDAR data are becoming available in many countries providing an opportunity to improve fuel monitoring at large scales. In this study, models were fitted to estimate canopy base height (CBH), fuel load (CFL) and bulk density (CBD) from airborne LiDAR in a pine stand area where four point-cloud datasets were acquired at different pulse densities. Best models for CBH, CFL and CBD fitted with LiDAR metrics from the 1 p/m2 dataset resulted in an adjusted R2 of 0.88, 0.68 and 0.58, respectively, with RMSE (MAPE) of 1.85 m (18%), 0.16 kg/m2 (14%) and 0.03 kg/m3 (20%). Transferability assessment of fitted models indicated different level of accuracy depending on LiDAR pulse density (both higher and lower than the calibration dataset) and model formulation (linear, power and exponential). Best results were found for exponential models and similar pulse density (1.7 p/m2) compared to lower (0.5 p/m2) or higher return density (4 p/m2). Differences were also observed regarding the canopy fuel attributes.

Prevalence of gross lesions and handling practices in pigs and their association with pork quality, Kiambu, Kenya.

Pre-slaughter handling of pigs has been documented to affect the quality of meat though no studies have investigated this relationship in the Kenyan context. This study aimed to determine the prevalence of gross lesions and practices related to sub-optimal welfare in pigs presented for slaughter while analyzing the relationship between occurrence of these lesions and meat quality. A cross-sectional study was conducted at a medium scale, non-integrated pig abattoir supplying to the Nairobi market, with a capacity to slaughter approximately 40 pigs a day. Data on welfare-associated lesions and handling practices were obtained from 529 pig carcasses and traders respectively. 387 pork samples were collected, and their quality evaluated by measuring their pH, meat color and drip loss. These three parameters were used to classify pork into four recognized categories namely: Red, Firm, Non-exudative (RFN), Pale Soft Exudative (PSE), Dark Firm Dry (DFD) and Red Soft Exudative (RSE). Almost all pigs were inefficiently stunned as evidenced by the presence of consciousness post-stunning. The majority of pigs (82.97%) having one or more welfare-associated gross lesions. Other animal welfare malpractices observed were high loading density and inadequate rest periods between transport and slaughter. A quarter of the pork samples were of sub-optimal quality including: RSE (11.36%), PSE (2.58%) and DFD (2.58%). Multinomial logistic regression revealed that pork originating from pigs transported at a high loading density had increased odds of being classified as DFD (OR 13.41, 95% CI 2.59–69.46). The findings indicate the need to educate stakeholders in the pork value chains on improved pig handling before and during slaughter to enhance pig welfare pre-slaughter and pork quality post-slaughter. Animal welfare legislation enforcement and implementation was observed to be insufficient. There is a need to educate key stakeholders on its importance of being put into practice both from economic and welfare perspectives.

Corrosion behavior of Graphene reinforced Al-12Si coated 7075 Aluminium alloy

This paper aims at investigating the effect of graphene reinforced Al-Si coatings on the corrosion behavior of AA7075 aluminium alloy. Al - 12Si alloy powder reinforced with 0.5 and 1 wt.% graphene was plasma sprayed on AA7075 substrate. Potentiodynamic polarization measurements were performed using CHI660E-CH electrochemical workstation. It was observed that 0.5 wt.% graphene reinforced Al-Si coating enhanced the corrosion potential from –0.893 to –0.761 V and reduced the corrosion current density from 1.3×10-4 to 9.78×10-6 A/m2. The atmospheric galvanic corrosion was simulated using COMSOL Multiphysics finite element package. It was observed that AA7075 aluminium electrode potential with respect to AISI 4340 steel increased from –0.76 to –0.59 V. The least average current density of 0.95 A/m2 was observed at 95 % relative humidity and 0.0035 kg/m2 salt load density indicating the minimum corrosion rate for 0.5 wt.% graphene reinforced Al-Si coated AA7075 substrate. The simulation also confirmed that 0.5 wt.% graphene reinforcement in Al-Si coatings enhanced the corrosion behavior of AA7075 when compared with 1 wt.% graphene reinforcement.

Comparison of Temperature Characteristics of Outer Rotor Low-Speed PM Motors Considering Magnetic Load and Current Density

In the electromagnetic design process of the outer rotor of a low-speed permanent magnet motor (LSPMM), due to the different heat dissipation conditions of the stator core and the stator winding, the selection of different magnetic loads and stator current densities will produce different temperature distributions even under the same efficiency. In the existing literature, the effects of magnetic load and current density on temperature distribution are rarely studied, which makes it difficult for designers to select optimal electromagnetic parameters to achieve better temperature performance. Therefore, in this paper, the comparison of temperature characteristics considering magnetic load and current density is conducted based on an outer rotor LSPMM. Firstly, the structure and parameters of an initial scheme of a 200 kW 56 rpm motor is determined, and the electromagnetic and temperature characteristics of the initial scheme are obtained through two-dimensional finite element analysis (2D-FEA) using Ansys Maxwell and Motor-CAD software. Secondly, by comparing the temperature and loss characteristics under different magnetic loads and different current densities, the effect of magnetic load on temperature and the effect of current density on temperature are obtained. Furthermore, four different schemes are proposed, and the loss and temperature characteristics of the four schemes under rated load are also compared to obtain the comprehensive effects of magnetic load and current density on temperature. Next, a final scheme is determined based on the above analysis, and the temperature characteristics of the final scheme and the initial scheme are compared to verify the validity of the conclusions. Finally, a prototype is built and tested to verify the feasibility of the conclusions. For LSPMM design, the results and several measurements provided in this paper can help researchers to choose a better optimization scheme to achieve good temperature performance.

Cost-optimization based target reliability for fire design of insulated steel columns

Adequacy of a structural fire design can in theory be demonstrated through a probabilistic risk assessment (PRA) where the compliance with tolerability limits and the ALARP requirement are explicitly ascertained. However, explicit assessment of ALARP requirement is challenging and impractical for day-to-day designs, due to the burden of estimating uncertain future costs and current safety investment costs. For normal design conditions, the use of target reliability indices has been recommended instead. These target reliability indices however have not been defined for structural design under fire events. To address this gap, the current study demonstrates a method to derive target reliability indices for a fire-exposed structure. As a case study, an insulated steel column (with varying levels of ISO fire rating) exposed to parametric natural fires is considered. The target reliability indices are derived for the steel column for varying fire exposure scenarios, considering different fire load densities and opening factor, relating to the building occupancies. This study thus investigates the important issue of adopting target reliability indices in fire design that are cost-optimized from quantitative analyses considering natural fire exposures, which has significant implications for fire safety and rational use of resources in the construction industry.

A Highly Compressible, Elastic, and Air‐Dryable Metallic Aerogels via Magnetic Field‐Assisted Synthesis

AbstractMetallic aerogels emerge as a group of materials for various applications since they exhibit the merits of both metal and aerogel. However, their performance characteristics are largely depreciated by the poor compressibility, elasticity, and complicated preparation process. Herein, a highly compressible and air‐dryable nickel nanowire aerogel (NNWA) is prepared via a facile magnetic‐field‐assisted gelation strategy. Its unique anisotropic lamellar structure and abundant cold‐welded junctions of intertwined nanowires enable superior electric conductivity and compression fatigue resistance. Such a free‐standing NNWA featured with ultralow density (20 mg cm−3) can be directly used as electrode scaffolds for energy storage and electrocatalysis purposes even at high mass loading (e.g., 10 mg cm−2) and large current density (e.g., 1 A cm−2) with superior performance. This method represents a general strategy for producing metallic aerogels with excellent comprehensive performance and mass‐production capability, providing a versatile platform for advanced applications.