Reinforcement Calculation of Circular and Annular Cross Section

Circular and annular cross-section is one of the more common cross-section forms, such as water towers, piers, etc. But reinforcement calculation of these crosssections is dual, the nonlinearity in width change and the nonlinear stress-strain relationship of concrete and reinforcement, which brings inconvenience to the calculation. In this paper, the corresponding calculation formulas are analytically derived and practical design charts (nomograms) are obtained. Based on stress-stain curve of concrete and reinforcement, five strain distribution regions were constructed. Via strains stress can be determined and then via the stress internal force can be computed, without application of the traditional equivalent rectangular stress block in concrete compression zone. The obtained dimensionless design charts can be applied to all load cases, such as uniform tension, tension with a small and large eccentricity, pure bending, compression with a large and small eccentricity and uniform compression. The calculation by using the design charts is simple and quick

Investigation on the Temperature Control Accuracy of a Print Head for Extrusion 3D Printing and Its Improved Design

For the extrusion 3D printing process, the printing temperature has a significant impact on the filament formation process because the rheological properties of the printed materials are extremely thermal sensitive, which requires a high temperature control accuracy of the print head. This paper presents a numerical and experimental investigation on the temperature field of a homemade print head. A finite element simulation model for analyzing the temperature field of the print head was established, by which the temperature distribution inside the print head can be acquired. Moreover, to improve the temperature control accuracy, an improved configuration was proposed, and two schemes were compared. The temperature control error dropped from 28% to 6.2% with the improved print head, which was verified experimentally. Furthermore, printing trials were conducted by the optimized print head. The filament diameter could be regulated by changing the temperature of the print head, which validates the feasibility to control the filament diameter during the extrusion process via temperature regulation

Developing A Case-Based Reasoning Model for Safety Accident Pre-Control and Decision Making in the Construction Industry

Case-based reasoning (CBR) has been extensively employed in various construction management areas, involving construction cost prediction, duration estimation, risk management, tendering, bidding and procurement. However, there has been a dearth of research integrating CBR with construction safety management for preventing safety accidents. This paper proposes a CBR model which focuses on case retrieval and reuse to provide safety solutions for new problems. It begins with the identification of case problem attribute and solution attribute, the state of hazard is used to describe the problem attribute based on principles of people’s unsafe behavior and objective’s unsafe state. Frame-based knowledge representation method is adopted to establish the case database from dimensions of slot, facet and facet’s value. Besides, cloud graph method is introduced to determine the attribute weight through analyzing the numerical characteristics of expectation value, entropy value and hyper entropy value. Next, thesaurus method is employed to calculate the similarity between cases including word level similarity and sentence level similarity. Principles and procedures have been provided on case revise and case retain. Finally, a real-world case is conducted to illustrate the applicability and effectiveness of the proposed model. Considering the high potential for pre-control and decision-making of construction safety accident, the proposed model is expected to contribute safety managers to take decisions on prevention measures more efficiently

Novel Variant Serotype of Streptococcus suis Isolated from Piglets with Meningitis

Choir apse, general view of the upper apse; Little remains of the abbey's important and influential medieval glazing. The windows of the Rayonnant choir and nave, probably the most important 13th-century ensemble in the Paris region before the glazing of the Sainte-Chapelle, were destroyed in the Revolution. They are documented only in a sketch, one of a series (Compiègne, Mus. Mun. Vivenel) made in 1794-1795 by Charles Percier, and the reliability of even this has been challenged (Lillich). Most of the glass outside of the ambulatory was reconstructed during the 19th century. Source: Grove Art Online; http://www.groveart.com/ (accessed 2/3/2008

Toxicity of Pekinenin C from Euphorbia Pekinensis Radix on Rat Small Intestinal Crypt Epithelial Cell and Its Apoptotic Mechanism

Pekinenin C is a casbane diterpenoid separated from the root of the traditional Chinese medicine, Euphorbia pekinensis Rupr., which is used as drug for the treatment of edema, ascites, and hydrothorax. Whereas pekinenin C exhibits severe cytotoxicity, the exact toxicity mechanism is unclear. In this study, the effects of pekinenin C on cell inhibition, cell cycle, and cell apoptosis were examined to explain its toxic mechanism. The proliferation of IEC-6 cells was accessed via MTT colorimetric assay after incubated with different concentrations of pekinenin C. Pekinenin C-treated IEC-6 cells labeled with RNase/PI and Annexin V/PI were analyzed by flow cytometric analyses for evaluation of cell cycle distribution and cell apoptosis, respectively. The apoptosis mechanism of pekinenin C on IEC-6 was investigated through assaying the activities of caspase-3, 8, 9 by enzyme-linked immunosorbent assay (ELISA), protein expression of Bax, Bcl-2, apoptosis-inducing factor (AIF), Apaf-1, Fas-associated death domain (FADD) and type 1-associated death domain (TRADD) by Western-blot, mRNA expression of Fas receptor (FasR), Fas ligand (FasL), tumor necrosis factor receptor (TNFR1) and NF-κB by RT-PCR. The results showed that pekinenin C has exhibited obvious IEC-6 cells toxicity and the IC50 value was 2.1 μg·mL−1. Typical apoptosis characteristics were observed under a transmission electron microscopy, and it was found that pekinenin C could cause G0/G1 phase arrest in IEC-6 cells in a dose-dependent manner and induce apoptosis of IEC-6 cells. Additionally, pekinenin C could increase the expressions of Bax, AIF, Apaf-1, FasR, FasL, TNFR1 and NF-κB, suppress the expression of Bcl-2, FADD and TRADD, then activate caspase-3, 8, 9 cascades, and at last result in apoptosis. These results demonstrated that pekinenin C effectively promoted cell apoptosis, and induced IEC-6 cells apoptosis through both the mitochondrial and death receptor pathways

Monitoring Liquid Level of Blast Furnace Hearth and Torpedo Ladle by Electromotive Force Signal

The state of a blast furnace hearth, especially the liquid level of hot metal and slag during the tapping process, is of crucial importance with respect to a long campaign blast furnace. In practice, the state of the hearth is evaluated mainly by the experience of operators. In this paper, the electromotive force (EMF) is used to monitor the liquid level of a laboratory scale of blast furnace hearth and the effect of liquid level, EMF sensors position and the thickness of refractory on EMF signals are tested using a single layer of water and double layers of water and oil. After laboratory experiments, the electromotive force (EMF) is used to monitor the liquid level of torpedo ladle successfully. Laboratory experimental results show that the change in liquid level can be characterized by EMF signal. The state of liquid surface and local thermal state cause the EMF signal to vary in the circumferential direction of the vessel. Furthermore, the EMF signal magnitude decreases with the decrease of the thickness of the graphite crucible. Finally, the main conclusions of the laboratory experiment are supported by the torpedo ladle experiment