The evaluation and interpretation of the behavior of construction materials under fire conditions have been complicated. Over the last few years, artificial intelligence (AI) has emerged as a ...reliable method to tackle this engineering problem. This review summarizes existing studies that applied AI to predict the fire performance of different construction materials (e.g., concrete, steel, timber, and composites). The prediction of the flame retardancy of some structural components such as beams, columns, slabs, and connections by utilizing AI-based models is also discussed. The end of this review offers insights on the advantages, existing challenges, and recommendations for the development of AI techniques used to evaluate the fire performance of construction materials and their flame retardancy. This review offers a comprehensive overview to researchers in the fields of fire engineering and material science, and it encourages them to explore and consider the use of AI in future research projects.
The reactions between Cu and the Sn2.5Ag0.8Cu solders doped with 0.03
wt.% Fe, Co, or Ni were studied. Reaction conditions included multiple reflows for up to 10 times and solid-state aging at 160
°C ...for up to 2000
h. In the multiple reflow study, Cu
6Sn
5 was the only reaction product noted for all the different solders used. Reflows using the solder without doping produced a thin, dense layer of Cu
6Sn
5. Adding Fe, Co, or Ni transformed this microstructure into a much thicker Cu
6Sn
5 with many small trapped solder regions between the Cu
6Sn
5 grains. In the solid-state aging study, both Cu
6Sn
5 and Cu
3Sn formed, but adding Fe, Co, or Ni produced a much thinner Cu
3Sn layer. Because the Cu
3Sn growth had been linked to the formation of micro voids, which in turn increased the potential for a brittle interfacial fracture, thinner Cu
3Sn layers might translate into better solder joint strength.
Knowledge of multidimensional correlation functions is crucial for understanding the anisotropy of turbulence. The two‐dimensional (2‐D) spatial correlation functions (SCFs) obtained in previous ...studies of space plasma turbulence were restricted to large‐length scales and covered a limited angular domain of the two‐point separation vector with respect to the mean magnetic field. Here we aim to derive 2‐D SCFs with smaller‐length scale and nearly full angular distribution for the fluctuations of the number density and magnetic field in magnetosheath turbulence. We use the Cluster four‐spacecraft measurements of the fluctuations with respect to a temporally and spatially varying background magnetic field to construct the 2‐D SCFs. We find that the correlation function of the density fluctuations shows a pattern similar to that of the magnetic field fluctuations, both of which appear to be composed of two populations, whereby the major population extends along the coordinate parallel to mean magnetic field (S∥) and the minor one deviates toward the perpendicular coordinate (S⊥). This pattern of 2‐D SCFs implies that the energy of magnetosheath turbulence seems to cascade, in the inertial range close to the ion scale, mostly transverse to the background magnetic field and meanwhile partly along the field (i.e., k⊥ ≫ k∥).
Key Points
First time to reveal the 2‐D correlation function in magnetosheath turbulence
Find the 2‐D correlation function to be composed of two populations
Major population for fluctuations with wave vectors transverse to B0
In conventional thermodynamics, it is widely acknowledged that the realization of an isothermal process for a system requires a quasistatic controlling protocol. Here we propose and design a strategy ...to realize a finite-rate isothermal transition from an equilibrium state to another one at the same temperature, which is named the "shortcut to isothermality." By using shortcuts to isothermality, we derive three nonequilibrium work relations, including an identity between the free-energy difference and the mean work due to the potential of the original system, a Jarzynski-like equality, and the inverse relationship between the dissipated work and the total driving time. We numerically test these three relations by considering the motion of a Brownian particle trapped in a harmonic potential and dragged by a time-dependent force.
Several studies discussed the relations between asthma and rheumatoid arthritis (RA) but the results were controversial. These studies were either questionnaire based or with small study populations. ...We aimed to examine the risk of asthma among RA patients in a nationwide population.
We conducted a cohort study using data from the National Health Insurance system of Taiwan. The RA cohort included 27 602 patients who were newly diagnosed and recruited between 1998 and 2008. Each patient was randomly frequency-matched with three people without RA on age group, sex and the year of index date from the general population. The occurrence of asthma was followed up until the end of 2010. The relative risks of asthma were estimated using Cox proportional hazard models after adjusting for age and comorbidities.
The overall incidence rate of asthma was 2.07-fold greater in the RA cohort than in the non-RA cohort (4.56 vs. 2.22 per 1000 person-years, 95% CI = 1.99-2.15). Stratified analyses by gender, age group and comorbidity revealed that the risk of asthma associated with RA was higher in females (adjusted hazard ratio (HR) = 2.18, 95% CI = 1.97-2.41), individuals younger than 40 years old (adjusted HR = 3.26, 95% CI = 2.09-5.11) and without comorbidity (adjusted HR = 2.17, 95% CI = 1.97-2.39).
Patients with RA had a significantly higher risk of developing asthma than healthy people in all sex and age subgroups. Stratified analyses indicated that there was a higher risk in women with RA than in men with RA when compared to their counterpart. Similarly, the HR of asthma associated with RA was higher in younger subjects, although the incidence rate increased with age.
Summary
PCV3 is an emerging swine virus associated with porcine dermatitis and nephropathy syndrome (PDNS), reproductive failure, respiratory diseases and systematic inflammation. Although first ...identified in 2015, the earliest case has been traced back to 2009 in the United States. In China, PCV3 infection was first detected in 2015, but little information has been available about its occurrence and prevalence there before 2015. In this study, 200 porcine clinical samples collected from 20 provinces, five autonomous regions and four municipalities between 1990 and 1999 were analysed for PCV3 infection by PCR. Results showed that 6.5% of the porcine samples collected from eight provinces and one autonomous region were PCV3 positive, with the earliest cases occurring in 1996. Nucleotide sequence analysis showed that PCV3 strains obtained in this study shared 96.6%–99.7% and 97.1%–99.4% sequence identity at the ORF2 gene and genome levels with all available reference strains from China and other countries, indicating the high genetic stability of PCV3 over the past 20 years.
Muconic acid is a valuable platform chemical with potential applications in the production of polymers such as nylon and polyethylene terephthalate (PET). The conjugate base, muconate, has been ...previously biosynthesized in the bacterial host Escherichia coli. Likewise, previous significant pathway engineering lead to the first reported instance of rationally engineered production of muconic acid in the yeast Saccharomyces cerevisiae. To further increase muconic acid production in this host, a combined adaptive laboratory evolution (ALE) strategy and rational metabolic engineering is employed. To this end, a biosensor module that responds to the endogenous aromatic amino acid (AAA) as a surrogate for pathway flux is adapted. Following two rounds of ALE coupled with an anti‐metabolite feeding strategy, the strains with improved AAA pathway flux is isolated. Next, it is demonstrated that this increased flux can be redirected into the composite muconic acid pathway with a threefold increase in the total titer of the composite pathway compared to our previously engineered strain. Finally, a truncation of the penta‐functional ARO1 protein is complemented and overexpress an endogenous aromatic decarboxylase to establish a final strain capable of producing 0.5 g L−1 muconic acid in shake flasks and 2.1 g L−1 in a fed‐batch bioreactor with a yield of 12.9 mg muconic acid/g glucose at the rate of 9.0 mg h−1. This value represents the highest titer of muconic acid reported to date in S. cerevisiae, in addition to the highest reported titer of a shikimate pathway derivative in this host.
To improve the muconic acid production in Saccharomyces cerevisiae, an adaptive laboratory evolution strategy is employed by adapting a biosensor module which responds to the endogenous aromatic amino acid as a surrogate for pathway flux. After two rounds of evolution followed by pathway optimization, a final strain capable of producing the highest titer of muconic acid reported to date in S. cerevisiae is established, in addition to the highest reported titer of a shikimate pathway derivative in this host.
Janus particles, which are named after the two-faced Roman god Janus, have two distinct sides with different surface features, structures, and compositions. This asymmetric structure enables the ...combination of different or even incompatible physical, chemical, and mechanical properties within a single particle. Much effort has been focused on the preparation of Janus particles with high homogeneity, tunable size and shape, combined functionalities, and scalability. With their unique features, Janus particles have attracted attention in a wide range of applications such as in optics, catalysis, and biomedicine. As a biomedical device, Janus particles offer opportunities to incorporate therapeutics, imaging, or sensing modalities in independent compartments of a single particle in a spatially controlled manner. This may result in synergistic actions of combined therapies and multi-level targeting not possible in isotropic systems. In this review, we summarize the latest advances in employing Janus particles as therapeutic delivery carriers, in vivo imaging probes, and biosensors. Challenges and future opportunities for these particles will also be discussed.
It has been a long‐standing debate on the nature of Elsässer variable z− observed in the solar wind fluctuations. It is widely believed that z− represents inward propagating Alfvén waves and ...interacts nonlinearly with z+ (outward propagating Alfvén waves) to generate energy cascade. However, z− variations sometimes show a feature of convective structures. Here we present a new data analysis on autocorrelation functions of z− in order to get some definite information on its nature. We find that there is usually a large drop on the z− autocorrelation function when the solar wind fluctuations are highly Alfvénic. The large drop observed by Helios 2 spacecraft near 0.3 AU appears at the first nonzero time lag τ = 81 s, where the value of the autocorrelation coefficient drops to 25%–65% of that at τ = 0 s. Beyond the first nonzero time lag, the autocorrelation coefficient decreases gradually to zero. The drop of z− correlation function also appears in the Wind observations near 1 AU. These features of the z− correlation function may suggest that z− fluctuations consist of two components: high‐frequency white noise and low‐frequency pseudo structures, which correspond to flat and steep parts of z− power spectrum, respectively. This explanation is confirmed by doing a simple test on an artificial time series, which is obtained from the superposition of a random data series on its smoothed sequence. Our results suggest that in highly Alfvénic fluctuations, z− may not contribute importantly to the interactions with z+ to produce energy cascade.
Key Points
A large drop is observed on the correlation function of z− in highly Alfvenic fluctuations by Helios and Wind
The autocorrelation function of an artificial random data series is shown to be similar to the observed ones
z− is suggested to be composed of high‐frequency white noise and low‐frequency pseudostructures in the studied cases
•Enhance Q by etch holes in 105MHz 5th order width extensional mode TPoS resonators.•Largest improvement in Q resulting from adding holes is 5.7 times on average.•Mechanism: Holes suppress ...axial-direction deformation in the supporting structures.•Effect of Q enhancement remains significant for different supporting tether lengths.•Enhancement in Q is mode selective – no enhancement at fundamental modes.
We report a unique method of using etch-holes to greatly improve the unloaded quality factor (Qu) of VHF-band low impedance laterally vibrating AlN Thin-film Piezoelectric-on-silicon (TPoS) MEMS resonators. We have validated the proposed method experimentally by applying it to fabricated devices operating at their 5th order modes with resonant frequencies of 105MHz. The largest improvement in Qu resulting from adding holes was found to be 5.7 times on average using the proposed method. The experimental results are corroborated by finite-element (FE) simulations which show that the holes re-distribute the strain energy in the resonator body. The re-distribution of strain energy consequently greatly suppresses the axial-direction deformation in the supporting beam tethers and undercut anchoring regions. Having less energy in the supporting tethers and undercut anchoring regions leads to a reduction of anchor loss and thus enhances Qu particularly when Qu is limited by anchor loss. It was also found that this effect of enhancing Qu through the proposed approach remains significant for different supporting tether lengths. Experimental results show that the increase in Qu going from plain resonators to resonators with holes is consistent regardless of tether lengths variation (i.e. the measured variation in Qu for different tether lengths is insignificant compared to the increase from adding etch holes). In comparison, no increase in Qu is observed when driving the same set of devices in their fundamental modes (22MHz) as the added holes do not suppress axial deformation in the supporting beam tethers and undercut anchoring regions as indicated by FE simulations. As such, the enhancement in Qu using the proposed approach is specific to the mode, thus offering the benefit of selectivity.
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