Thermo-Elasto-Plastic Behavior of Biaxially Loaded Steel Beam-Columns Inducing Those From World Trade Center Towers

An experimental and theoretical investigation into the behavior of biaxially loaded steel beam-columns is conducted including the effects of high temperature. Systems of materially nonlinear differential equations of beam-column equilibrium are first formulated for both ambient and high temperature conditions. An iterative finite integral procedure is formulated and programmed to solve the governing differential equations. To check the validity of the theoretically predicted behavior and strength of the beam-columns, a series of forty-two laboratory tests are conducted at both ambient and high temperature up to 950°F. Upon achieving a good agreement between the predicted beam-column behavior and that observed in the experiments, the theory developed is then applied to predicting the behavior and strength of typical beam-columns which were used in the 110-story World Trade Center (WTC) buildings. Thermo-elasto-plastic stiffness degradation and load-moment interaction curves are generated for typical WTC beam-columns which existed in the impacted area during 9/11 attacks

Preparation and Photocatalytic Activity of Fe3+ - doped TiO2 Modified

Photocatalytic materials of TiO2 / coarse silica gel microspheres were prepared by sol-gel impregnation method and doped with transition metal ions Fe3+ to form Fe3+ modified TiO2 / coarse silica gel microspheres. The surface of the Fe modified photocatalytic materials were analyzed by XRD and surface scanning. Degradation of reactive dyes using X-3B dye wastewater water samples for validation tests. The results show that the photocatalytic activity of the photocatalytic material reaches the best when the Fe doping amount is 0.5%, and the most photocatalyst amount is 10g / L. The degradation rate of COD under this dosage was 72.32%. At the same time, according to the characterization analysis, it was found that Fe did not react with the photocatalytic material of TiO2 / coarse silica microspheres in the reaction, Fe increased the defect structure of TiO2 surface and promoted the formation of anatase, A red shift occurred and the corresponding range of the spectrum expanded toward the visible region. The results show that the doping of Fe affects the formation of TiO2 crystals, but increases the photocatalytic efficiency of TiO2

INFLUENCE OF RARE-EARTH DOPING ON THE ELECTRICAL PROPERTIES OF HIGH VOLTAGE GRADIENT ZnO VARISTORS

The influence of rare-earth doping on the electrical properties of ZnO varistors was investigated. In a lower doping region, the electrical properties were greatly improved with the increase of rare-earth contents. The highest voltage gradient value of 1968.0 V/mm was obtained with a rare-earth concentration of 0.06 mol. %. The microstructure of samples with different amounts of rare-earth oxides was examined and the notable decrease of grain size was identified as the origin for the increased voltage gradient. The doped rare-earth oxides dissolved at the grain boundaries and the excessive doping reduced the voltage across the single grain/grain boundary from 2.72 V to 0.91 V. The poor electrical properties in a higher doping region resulted from the degeneration of grain boundaries and the decrease of block density

Review of CD4+ T cell subsets in asthma phenotypes: molecular mechanisms and biologic treatment options

Asthma is a chronic inflammatory airway disease, mainly driven by different CD4+ T cell subsets [helper T cell (Th cell)]. CD4+ T cell subsets are a type of important immune cells, capable of secreting various cytokines, and regulating the immune response of the body to various antigens. According to the difference of secreted cytokines, CD4+ T cell subsets can be divided into subgroups such as Th1, Th2, Th17, follicular helper T cell (Tfh) and regulatory T cell (Treg), which play different roles in the occurrence and development of asthma. Biologic therapy is a new treatment method that targets specific molecules and pathways, and has provided more options for asthma patients. Biologics is a type of drugs prepared by biotechnology, which can specifically recognize and neutralize target molecules, thereby interfering with related signaling pathways. This article reviews the roles and molecular mechanisms of various CD4+ T cell subsets in asthma phenotypes, summarizes the immunopathological characteristics of eosinophilic asthma, neutrophilic asthma and mixed asthma, the clinical efficacy and safety of biologics targeting Th2, Th1, Th17, Tfh and Treg cell-related factors, and the selection and development direction of corresponding biologics. This article also discusses the role of impaired Treg cells and abnormal dendritic cells (DC cells) in the pathogenesis of asthma, as well as the potential of immunotherapy using these cells. This article aims to provide reference for the personalized selection and new drug development of biologic therapy for asthma

The Connecting Method for the Spiral Blades of Concrete Mixer Truck

For the spiral blade of the concrete mixing tank of concrete mixer truck, in order to satisfy the stirring and discharging performance, the installation angle and helix angle of the blade should be assigned according to their segmentation function. Due to the different helix angles and the installation tilt angles, a junction gap of blade is formed at the joint, resulting in the severe silting of discharge or the uneven agitation. We put forward a more reasonable solution by using the MFG (method of fitting gradient) to solve the gap connection of spiral blades. The MFG that can reduce the discharging residual rate of the mixing material has been verified by experiments and applied to actual mass production. We also make the coupling simulation of Multi-Physics Field based on simulation software 17-STARCCM+® to visually verify the scientificity of design and study the complex stresses distribution inside the actual mixing tank. Finally, we provide an up-to-date reference for the design of spiral logarithmic blade, solving the problem of the gap at the traditional spiral-blade connection

AZI23'UTR Is a New SLC6A3 Downregulator Associated with an Epistatic Protection Against Substance Use Disorders

Regulated activity of SLC6A3, which encodes the human dopamine transporter (DAT), contributes to diseases such as substance abuse disorders (SUDs); however, the exact transcription mechanism remains poorly understood. Here, we used a common genetic variant of the gene, intron 1 DNP1B sequence, as bait to screen and clone a new transcriptional activity, AZI23'UTR, for SLC6A3. AZI23'UTR is a 3' untranslated region (3'UTR) of the human 5-Azacytidine Induced 2 gene (AZI2) but appeared to be transcribed independently of AZI2. Found to be present in both human cell nuclei and dopamine neurons, this RNA was shown to downregulate promoter activity through a variant-dependent mechanism in vitro. Both reduced RNA density ratio of AZI23'UTR/AZI2 and increased DAT mRNA levels were found in ethanol-naive alcohol-preferring rats. Secondary analysis of dbGaP GWAS datasets (Genome-Wide Association Studies based on the database of Genotypes and Phenotypes) revealed significant interactions between regions upstream of AZI23'UTR and SLC6A3 in SUDs. Jointly, our data suggest that AZI23'UTR confers variant-dependent transcriptional regulation of SLC6A3, a potential risk factor for SUDs