Process Simulation of Sulfuric Acid Recovery by Azeotropic Distillation: Vapor–Liquid Equilibria and Thermodynamic Modeling

For development of the new process for the recovery of dilute sulfuric acid by azeotropic distillation proposed in our earlier publication [Li et al., <i>Ind. Eng. Chem. Res.</i>, <b>2013</b>, <i>52</i>, 3481–3489], in this paper, the vapor–liquid equilibria (VLE) for the FeSO₄ + H₂O and H₂SO₄ + FeSO₄ + H₂O systems were first determined by the quasi-static ebulliometric method. The azeotropic temperatures of the H₂SO₄ + H₂O + entrainer (cyclohexane and octane) systems were also measured. The corresponding electrolyte nonrandom two-liquid interaction parameters were obtained by regressing the experimental data with a maximum average absolute deviation of boiling points of 0.83 K. The model with newly obtained parameters was verified by comparing its prediction with the experimental azeotropic temperature for the H₂SO₄ + FeSO₄ + H₂O + C₆H₁₂ quaternary system. The temperature and sulfuric acid concentration ranges of the study were 305.9–396.9 K and 0–86.1 wt %, respectively. Following from the experimental results, semicontinuous distillation experiments for the sulfuric acid recovery were performed with cyclohexane as the entrainer. Equipped with the new parameters, Aspen Plus was adopted to carry out the process simulation for the recovery of dilute sulfuric acid by azeotropic distillation. The simulation results show that when cyclohexane was employed as the entrainer, the dilute sulfuric acid can be concentrated to 68% by a packed column containing 4 theoretical stages and with a reboiler temperature of only 361 K

Scanning Single-Molecule Fluorescence Correlation Spectroscopy Enables Kinetics Study of DNA Hairpin Folding with a Time Window from Microseconds to Seconds

Single-molecule fluorescence measurements have been widely used to explore kinetics and dynamics of biological systems. Among them, single-molecule imaging (SMI) is good at tracking processes slower than tens of milliseconds, whereas fluorescence correlation spectroscopy (FCS) is good at probing processes faster than submilliseconds. However, there is still shortage of simple yet effective single-molecule fluorescence method to cover the time-scale between submilliseconds and tens of milliseconds. To effectively bridge this millisecond gap, we developed a single-molecule fluorescence correlation spectroscopy (smFCS) method that works on surface-immobilized single molecules through surface scanning. We validated it by monitoring the classical DNA hairpin folding process. With a wide time window from microseconds to seconds, the experimental data are well fitted to the two-state folding model. All relevant molecular parameters, including the relative fluorescence brightness, equilibrium constant, and reaction rate constants, were uniquely determined

Mapping and modelling defect data from UAV captured images to BIM for building external wall inspection

With the increase of service years, external walls of high-rise buildings tend to suffer from a variety of defects which impose great safety risks. Traditional methods for inspecting high-rise building external walls require inspectors to work at height and identify defects manually, which is dangerous and inefficient. In recent years, there has been an increasing trend of using unmanned aerial vehicles (UAV) for inspecting building external walls, but how to manage the information obtained by the UAV is still a problem. In addition, although building information modelling (BIM) with rich geometric and semantic information has been applied in the construction engineering industry, BIM models usually lack updated condition data of facilities. Therefore, this paper presents a method for managing the inspection results of building external walls by mapping defect data from UAV images to BIM models and modelling defects as BIM objects. First, images of building external walls obtained by UAV are processed and useful information such as coordinates are extracted. Considering the small scale of single buildings, a simplified coordinate transformation approach is developed to transform location of real-world defects to coordinates in the BIM model. Meanwhile, a deep learning-based instance segmentation model is developed to detect defects in the captured images and extract their features. In the end, the identified defects are modelled as new objects with detailed information and mapped to the corresponding location of the related BIM component. To validate the feasibility, the proposed method has been applied to a real office building, which successfully mapped and integrated the defects of external walls with the BIM model. This study is applicable to both buildings and infrastructure, and is expected to facilitate structure inspection and decision making in maintenance with integrated data of as-is condition and as-built BIM

The proposed metabolic pathways of eleutheroside B₁ (21), rosmarinic acid-4- O-<i>β</i>-D-glucoside (56) and quercetin-3-<i>O</i>-<i>β-</i>D-glucuronide (57) in rat plasma after oral administration.

<p>The proposed metabolic pathways of eleutheroside B₁ (21), rosmarinic acid-4- O-<i>β</i>-D-glucoside (56) and quercetin-3-<i>O</i>-<i>β-</i>D-glucuronide (57) in rat plasma after oral administration.</p

Detected metabolites of 18, 21, 45, 54, 56, 57 and 64 in rat plasma after oral administration in single or extract forms.

<p>Detected metabolites of 18, 21, 45, 54, 56, 57 and 64 in rat plasma after oral administration in single or extract forms.</p

Effects of 15 metabolites (4, 18, 21, 31, 32, 36+39, 45, 55–57, 64, 82, 88, 89 and 98) on NO production in LPS-stimulated RAW264.7 macrophages.

<p>Cells were treated with LPS (1μg/ml) in the absence or presence of the constituents at different concentrations for 24 h. Amounts of NO were determined using the Griess reagent kits; ++p<0.01,control group vs LPS-stimulated group; +p<0.05,control group vs LPS-stimulated group;**P<0.01, LPS vs LPS plus constituents-treated group. B. Values shown in the graphs are mean ± standard deviation (n = 3).</p

Effects of 52, 54, 62, 63 and 101 on inflammation-related gene expression in LPS-stimulated RAW 264.7 macrophages.

<p>Cells were treated with LPS (1μg/mL) in the absence or presence of the constituents at different concentrations for 10 h. The mRNA level was analyzed using real-time PCR; ++p<0.01, control group vs LPS-stimulated group; +p<0.05, control group vs LPS-stimulated group; **P<0.01, LPS vs LPS plus constituents-treated group. Values shown in the graphs are mean ± standard deviation (n = 3).</p

The strategy for systematic screening and identification of the absorbed constituents and metabolites in <i>S</i>. <i>glabra</i> by UHPLC–LTQ-Orbitrap

<p>The strategy for systematic screening and identification of the absorbed constituents and metabolites in <i>S</i>. <i>glabra</i> by UHPLC–LTQ-Orbitrap</p

Additional file 3: of Proteomic analysis of maize grain development using iTRAQ reveals temporal programs of diverse metabolic processes

The homologs of uncharacterized proteins in maize grains (XLSX 48 kb

Additional file 1: of A statistical analysis plan for the efficiency and safety of Chinese herbal medicine used concurrently with topical therapy for psoriasis vulgaris

List of approvals from six hospitals’ ethics committees and archival filing management required in five hospitals’ ethics committees. (DOC 26 kb