Test System for Detailed Model of Transformers for Transient Analysis Using the Electromagnetic Transient Program (EMTP)

This paper describes a detailed model of a transformer designed to evaluate the ability of winding insulation to withstand transients. The time domain electromagnetic transient program (EMTP) was used to develop a model of the transient characteristics of the winding. It is difficult for students to use EMTP and understand simulation results. This paper contains all the data needed to develop a detailed model for transient analysis and presents basic case studies and alternative design/operating configurations.     

IR Thermographic Analysis of 3D Printed CFRP Reference Samples with Back-Drilled and Embedded Defects

Carbon-fiber composite structures may demonstrate a defective behavior due to manufacturing induced anomalies (delamination, dis-bonds) or service related defectives (impact damage, water ingress). Thus, there is a need for a relatively fast and low cost non-intrusive testing schemes such as infrared thermography (IRT). Still, thermography testing requires calibrated samples and coupons to yield best results. The presented research demonstrates the novel use of 3D printing technology to generate IRT calibration samples. In this text, two carbon fiber reinforced polymer samples are 3D printed; the first mimics a “back-drilled holes” type coupons, while the other is designed to embed air pockets similar to Teflon inserts. The generated samples are then tested using two IRT modalities; namely pulse thermography and lock-in thermography. Furthermore, the resulted thermograms are processed using a principle component analysis, to help highlight the variance of defectives in a consistent manner among the samples. This research findings offer insights on the variation of detectability between embedded and back-printed samples, which might be due to the inserts thickness.     

Poly(2-hydroxyethylmethacrylate-co-2-folate ethylmethacrylate) and Folic acid/Poly(2-hydroxyethylmethacrylate) Solid Solution: Preparation and Drug Release Investigation

Poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) was synthesized by free radical polymerization of 2-hydroxyethylmethacrylate with 2-folatethylmethacrylate and folic acid/poly(2-hydroxyethylmethacrylate) solid solutions was prepared by mixing folic acid with poly(2-hydroxyethylmethacrylate) using the solution casting method. The structure and the homogeneity distribution of folic acid in the polymer matrix are characterized by different methods. The diffusion behaviors of water and folic acid through poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) and poly(2-hydroxyethylmethacrylate) matrixes were found obey to the Fick models. The in vitro cytotoxicity assessed by microculture tetrazolium test assay and the antioxidant activity of poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) systems determined by 1,1-diphenyl-2-picryl-hydrazyl method revealed no significant toxicity of these systems and has excellent free radical scavenger property which can be as safe candidate in drug-carrier system. The solubility enhancement of folic acid in different pH media is also investigated and the results obtained reveal a maximum of 399–400?mg?L^?1. The release dynamic of folic acid from the poly(2-hydroxyethylmethacrylate-co-2-folatethylmethacrylate) containing 5?mol% of folic acid and that from folic acid/poly(2-hydroxyethylmethacrylate) system containing 10?mol% of folic acid have the best intestine/stomach ratio.     

Design of a reversible structure for memory in quantum-dot cellular automata

Complementary metal oxide semiconductor (CMOS) technology has limitations in reducing the area and size of circuits. The disadvantages of this technology include high power consumption and temperature problems. Quantum-dot cellular automata (QCA) is a new technology that can overcome these shortcomings. Reversible logic is technology used to reduce the power loss in QCA. QCA can be used to design memories that require high operating speed. In this paper, we propose a structure for the reversible memory in QCA. The proposed structure utilizes three-layer technology, which has a significant impact on circuit size reduction. The proposed structure for the reversible memory has 63% improvement in cell number, a 75% improvement in area occupancy, and a 60% reduction in delay compared to the previous best structure.     

ASM2Bogor: An approach for verification of models specified through Asmeta language

Nowadays, publish–subscribe (pub-sub) and event-based architectures are frequently used for developing loosely coupled distributed systems. Hence, it is desirable to find a proper solution to specify different systems through these architectures. Abstract state machine (ASM) is a useful means to visually and formally model pub–sub and event-based architectures. However, modeling per se is not enough since the designers want to be able to verify the designed models. As the model checking is a proper approach to verify software and hardware systems, in this paper, we present an approach to verify ASM models specified in terms of Asmeta language using Bogor—a well known model checker. In our approach, the AsmetaL specification is automatically encoded to BIR, the input language of the Bogor. Our experimental results show that in the most cases our approach generates more efficient results in comparison with the existing approach.     

SO2 Removal from Gas Streams by Ammonia Scrubbing: Process Optimization by Response Surface Methodology

Reduction of the SO₂ content by ammonia scrubbing in the incinerator of the Isfahan Refinery complex was investigated. An experimental continuous setup was designed to study the underlying process parameters affecting SO₂ capture from air. The effects of various parameters was analyzed by a systematic experimental design based on response surface methodology with central composite design. The developed response surface model was found to be useful and robust to predict the degree of desulfurization of ammonia wet flow gas disulfurization reactors. The ammonia concentration had the most significant influence on the efficiency of the desulfurization process. The square of temperature affected the efficiency more than the temperature, whereas the gas flow rate had a minor influence on the separation efficiency.     

Mathematical Model Validation of Search Protocols in MP2P Networks

Broadcasting is a basic technique in Mobile ad-hoc network (MANET), and it refers to sending a packet from one node to every other node within the transmission range. Flooding is a type of broadcast where the received packet is retransmitted once by every node. The naive flooding technique, floods the network with query messages, while the random walk technique operates by contacting the subsets of every node’s neighbors at each step, thereby restricting the search space. One of the key challenges in an ad-hoc network is the resource or content discovery problem which is about locating the queried resource. Many earlier works have mainly focused on the simulation-based analysis of flooding, and its variants under a wired network. Although, there have been some empirical studies in peer-to-peer (P2P) networks, the analytical results are still lacking, especially in the context of P2P systems running over MANET. In this paper, we describe how P2P resource discovery protocols perform badly over MANETs. To address the limitations, we propose a new protocol named ABRW (Address Broadcast Random Walk), which is a lightweight search approach, designed considering the underlay topology aimed to better suit the unstructured architecture. We provide the mathematical model, measuring the performance of our proposed search scheme with different widely popular benchmarked search techniques. Further, we also derive three relevant search performance metrics, i.e., mean no. of steps needed to find a resource, the probability of finding a resource, and the mean no. of message overhead. We validated the analytical expressions through simulations. The simulation results closely matched with our analytical model, justifying our findings. Our proposed search algorithm under such highly dynamic self-evolving networks performed better, as it reduced the search latency, decreased the overall message overhead, and still equally had a good success rate.     

High-level evidences in endodontics

Number of published medical/dental articles is growing at an exponential rate; this makes it difficult to collect all these resources and provide an organized and valuable/useful document. Systematic reviews and meta-analyses as high-level evidences are considered remedies for this concern. Continuous alterations in all fields of dental sciences necessitate the more of such high-level evidences. This study aimed on the quantity of endodontic systematic reviews and meta-analyses so far. This study began with targeted electronic searches of PubMed, and Cochrane library databases about the present systematic review and meta-analysis articles in endodontics within 2001–Jan 2012. Overall, 49 studies were systematic review and meta-analysis, the first comprised 34 articles and the latter contained seven articles; the remained eight studies had utilized both of them. Performing a topic sorting, 22 articles were about materials and techniques, 12 about pre- and post-treatment considerations, four about single/multiple visits, six with perio-prostho themes, and the five remained were of other topics. Limited number of 49 high-level evidences does not meet the expectation from endodontics as a boundless and progressive field of science. Therefore, more comprehensive and all-inclusive studies of systematic reviews and meta-analyses are compulsory in endodontics. The more the scientific-based endodontic practice, the more the high-level evidence based publications with good systematic reviews and favorable meta-analysis.     

Structural biology of HIV

The human immunodeficiency virus (HIV) genome encodes a total of three structural proteins, two envelope proteins, three enzymes, and six accessory proteins. Studies over the past ten years have provided high-resolution three-dimensional structural information for all of the viral enzymes, structural proteins and envelope proteins, as well as for three of the accessory proteins. In some cases it has been possible to solve the structures of the intact, native proteins, but in most cases structural data were obtained for isolated protein domains, peptidic fragments, or mutants. Peptide complexes with two regulatory RNA fragments and a protein complex with an RNA recognition/encapsidation element have also been structurally characterized. This article summarizes the high-resolution structural information that is currently available for HIV proteins and reviews current structure-function and structure-biological relationships.     

Evaluation of two new white silicone thermal control paints under atomic oxygen

The exterior optical surfaces of satellites are directly exposed to the harsh space environment. Thermal control paints are resistant to the conditions encountered at low earth orbit (LEO): vacuum, atomic oxygen, thermal cycling, and ultraviolet radiation. In this paper two white paints were prepared by ultrasonic dispersing method for application to space structures. The white paints include zinc-oxide-pigmented silicone elastomer SilGel 612 (U1) and a zinc-oxide-pigmented silicone elastomer RT604 (U2). These coatings are electrically non-conductive. We present the behavior of thermal control paints under atomic oxygen (AO). The effects of AO exposure were studied by the mass loss of paint specimens and complementary techniques including scanning electron microscopy (SEM) and atomic force microscopy (AFM). Also the optical degradation in the reflectance spectra, solar absorptance and thermal emittance for U1 and U2 samples before and after AO exposure were investigated. The paints have promising AO resistance properties that could be suitable for space applications.