Experimental and computational study of thermal behavior of PVC composites based on modified eggshell biofiller for UPVC product

Journal of Polymer Research - There are few commercially available β-nucleating agents (β-NAs) that can induce Polypropylene random copolymer (PPR) to produce large amounts of...     

Two effective methods to detect anomalies in embedded systems

Current-day embedded systems are very vulnerable to faults and defects. Anomaly detection is often the primary means of providing early indication of faults and defects. This paper presents two methods for detecting anomalies in embedded systems. The first method, buffer based detector, constructs a buffer consisting of events from a stream of data considered to be normal. Consequently, during test stage, if an event does not exist in the buffer, a miss will happen. An anomaly exists in test data provided that the hit rate of the buffer does not reach a predefined threshold. The second method namely probabilistic detector employs the probability of data events to evaluate the behavior of system. In order to measure the probability of events in the system, sampling of two events with distinct distance is done. Eventually, during test stage, the probability of events can be measured. An anomaly exists in test data provided that this probability does not reach a predefined threshold. A comparison between these two methods and other typical methods has been done based on detection coverage, area overhead and delay overhead. The experiments on 112 standard benchmarks show that the proposed methods can detect 100% of anomalies. Also, the area overhead of the proposed detectors grows linearly, while the area overhead of other typical detectors grows exponentially by the increase in one of the detector's parameters.     

Wood–high‐density polyethylene composites: Water absorption and mechanical properties

In this research, the effect of water absorption on the mechanical properties of wood/high‐density polyethylene (HDPE) composites were investigated. HDPE (44005ARPC) was used as the polymer matrix, and spruce sawdust was used as the filler at a maximum loading of 50 wt % of the total weight of each compound. All compounds contained 5 wt % magnesium stearate as a lubricant and 0.5 wt % Irgafos 168 as a heat stabilizer. Four factors in two levels were chosen [talc (filler) at levels of 5 and 15 wt %, zinc borate (fungicide) at levels of 0 and 1 wt %, maleic anhydride polyethylene (coupling agent) at levels of 4 and 6 wt %, and method of mixing (one‐step vs. two‐step mixing)], and eight compounds were prepared with an L8 Taguchi orthogonal array which has 8 combinations of levels. The effects of each factor at two levels on the diffusion constant and the tensile and bending strengths (under wet and dry conditions) were investigated by the analysis of variance of means with 90% confidence. The optimum level for each factor is reported. The results show that there was a linear correlation between the diffusion constant and tensile and bending strengths when the samples were immersed in distilled water. A higher diffusion constant resulted in much lower tensile and bending strengths with immersion in distilled water until saturation was reached. Scanning electron microscopy images confirmed good mixing when two‐steps mixing was used. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Structural optimization of four designed roof modules: Inspired by Voronax grid shell structures

Architects have been following nature in their constructions for a long time. Observations of nature reveal that it has many highly developed structures that provide scientists and engineers with a lot of useful clues for creating more efficient structures and building forms. Therefore, revealing systematic thinking about natural species is a crucial requirement for today’s buildings. A software analysis method was used to design four modules in the roof structure of the Iranian University of Science and Technology’s exhibition. The roof structure is based on the Voronax structure, which is a relaxed formof Voronoi, which is seen in the structures ofmany natural creatures. They were analyzed in terms of optimization and structural simulation using Grass-hopper plugins and tools by taking into account VonMises stress in the structural design. The results indicated that by increasing the density of Voronax cells in the areaswith high Von Mises stress concentration, a more efficient structure could be achieved in terms of load-bearing and designing predefined free-form roof structures. By analyzing predefined roof structures in an optimum way, the study took a step toward optimizing these kinds of structures.     

Mechanistic Observation of Interactions between Macrophages and Inorganic Particles with Different Densities

Many different types of inorganic materials are processed into nano/microparticles for medical utilization. The impact of selected key characteristics of these particles, including size, shape, and surface chemistries, on biological systems, is frequently studied in clinical contexts. However, one of the most important basic characteristics of these particles, their density, is yet to be investigated. When the particles are designed for drug delivery, highly mobile macrophages are the major participants in cellular levels that process them in vivo. As such, it is essential to understand the impact of particles’ densities on the mobility of macrophages. Here, inorganic particles with different densities are applied, and their interactions with macrophages studied. A set of these particles are incubated with the macrophages and the outcomes are explored by optical microscopy. This microscopic view provides the understanding of the mechanistic interactions between particles of different densities and macrophages to conclude that the particles’ density can affect the migratory behaviors of macrophages: the higher the density of particles engulfed inside the macrophages, the less mobile the macrophages become. This work is a strong reminder that the density of particles cannot be neglected when they are designed to be utilized in biological applications.