Determining the heat flux absorbed by satellite surfaces with temperature data

This study aims to determine the heat flux absorbed by satellite surfaces with the use of temperature data acquired from the satellite. This process is the first step in the development of an attitude determination method, which is currently being conducted by the authors. The principles of heat flux determination and its limitations are explained. A simple heat flux sensor is proposed in this study to address such limitations. With sufficient temperature data, an inverse solution of the energy equation can be used to determine the heat fluxes absorbed by heat flux sensors. The accuracy of the method depends on the resolution of the sensors used to acquire temperature data. The effects of temperature sensor resolution on the accuracy of the results are discussed in this paper.     

Development of an inductive encoder for simultaneous measurement of two-dimensional displacement

Two-dimensional measurements are usually performed by two one-dimensional devices. In this paper, a simple method is developed, which can directly measure the displacements in two dimensions. The measurement is based on inductive method where a flat coil moves on another flat coil and the induced voltages give the displacements in x and y directions. In this research, five flat coils with special patterns are used. One is stationary and four others make the moving part. When moving part moves on the stationary surface, two of the moving coils detect the displacement in x direction and the other two detect the displacement in y direction. The patterns of the coils are designed in a way that there is no interference between axes, i.e., movement in one dimension has no effect on data of other dimension. The experimental results show the effectiveness of the concept. Resolution of 10 μm and no interference between axes are achieved. Better resolution is expected if more precise experimental device is provided.     

Computer-aided design of structures using LISP

An experimental knowledge-based expert system, called SSPG. is presented for design of stiffened steel plate girders, using the LISP programming language. Employing previously acquired knowledge of the optimum span-to-web depth ratios, SSPG is capable of yielding a “practical” minimum weight design without performing a costly formal optimization. This research indicates the effectiveness of the LISP language for computer-aided design of structures where not only subjective knowledge and heuristics are needed but also substantial numerical computations are involved.     

Interactive microcomputer-aided design of circular suspension cable roofs

This paper presents interactive computer-aided design of circular suspension cable roofs. A microcomputer program developed in Advanced BASIC and according to the principles of structured programming is presented. The program can display/plot the plan of cable roof, the elevation of the structure including the loading on the cables and the cross-section of the reinforced concrete compression ring. The interactive program helps the user to explore many design alternatives rapidly and arrive at a practically optimum design.     

Antioxidase-Like Nanobiocatalysts with Ultrafast and Reversible Redox-Centers to Secure Stem Cells and Periodontal Tissues

Exploration of efficient antioxidase-like reactive oxygen nanobiocatalysts (ROBCs) is a major challenge in combating oxidative stress-related diseases. Herein, the molecularly well-defined Ru-porphyrin-networks (Ru-Por-Net)-based ROBCs with ultrafast and reversible redox-centers for catalytic elimination of reactive oxygen species (ROS) are reported. Owing to the large π-conjugated networks, Ru–N coordination structures, and unique electronic and redox properties of atomic Ru sites, the Ru-Por-Net-based ROBCs exhibit exceptional catalytic ROS-scavenging activities. It is considerably more efficient than recently reported state-of-the-art anti-ROS biocatalysts. Notably, a new nucleophilic attack pathway to eliminate H₂O₂ and produce O₂ is proposed via theoretical calculations, and the desorption of the OO* process is identified as the rate-determining step of atomic Ru centers. Cellular studies reveal that the new ROBCs can efficiently secure the survival, adhesion, spreading, and differentiation of the stem cells in high-ROS-level microenvironments. In vivo rat periodontitis treatments further demonstrate their superior anti-ROS therapeutic effects. This study provides significant insights into the crucial functions of Ru–N coordinated porphyrin-networks in catalytic ROS-scavenging and offers a new strategy to engineer high-performance antioxidase-like nanobiocatalysts for stem cell-based therapies and inflammatory diseases.     

Preparation and investigation of properties of deproteinized natural rubber nanocomposites incorporating functionalized nano-alumina by in situ emulsion polymerization

The present study reports the preparation, characterization, and investigation of properties of DNR/f-Al₂O₃ nanocomposites through an in situ emulsion polymerization technique. The method consists of the dispersion of pretreated nano-alumina (f-Al₂O₃ NPs) onto deproteinized natural rubber (DNR) latex, followed by the polymerization reaction with the K₂S₂O₈/K₂S₂O₅ redox initiation system, after deproteinization of natural rubber using urea in the presence of a surfactant. To improve the compatibility and reactivity of the nanofillers with DNR latex, the nano-alumina surface was treated with 3-methacryloxypropyltrimethoxysilane (MPS) to produce f-Al₂O₃ NPs. The thermo-gravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy approved that the MPS was bound onto the surface of Al₂O₃ NP. The resulting nanocomposites were characterized using standard techniques for physical properties and structural morphology, including X-ray diffraction (XRD) analysis, FTIR spectroscopy, scanning electron microscopy (SEM), and TGA. The SEM images showed a homogeneous distribution of f-Al₂O₃ NPs throughout DNR matrix. Due to such monodisperse particles, the DNR/f-Al₂O₃ nanocomposite films revealed significant enhancement in thermal stability with increasing nano-alumina loading as compared with the neat DNR.