The Viscosity of Crude Oils in 1,4-Dioxan

Viscosities of crude oil solutions from 0.1 to 1.0% (v/v) have been studied in 1,4-Dioxan as a solvent at temperature ranging from 293 to 313 K. Huggins, Kraemer, Martin, and Schulz-Blaschke relations were used by viscosity data to evaluate intrinsic viscosities and viscometric constant values. Degree of viscosity reduction (DVR) was also calculated. The size of the isolated molecule was evaluated in terms of intrinsic viscosity and shows that interactions between solute and solvent decrease with the rise in temperature.     

A frequency response based structural damage localization method using independent component analysis

Vibration-based structural damage detection has been the focus of attention by many researchers over the last few decades. However, most methods proposed for this purpose utilize extracted modal parameters or some indices constructed on the basis these parameters. Our literature review revealed that few papers have employed frequency response functions (FRFs) for detecting structural damage. In this paper, a technique is presented for damage detection which is based on measured FRFs. Independent component analysis (ICA) has been implemented on the spatiotemporal responses in each frequency in order to reduce the dimension of the data. This is based on the concept that the forced harmonic response of a linear vibrating system can be fully captured utilizing a single ICA mode. A different approach is also presented in which ICA is applied to the frequency domain data. Operational deflection shapes (ODSs) have been decomposed using ICA to localize the damage. The efficiency of both methods is demonstrated through some numerical and experimental case studies.     

Bird strike analysis on a typical helicopter windshield with different lay-ups

In the current paper, bird strike to a typical helicopter windshield is investigated using smoothed particles hydrodynamic (SPH) finite element method. Five types of lay-ups in a windshield (single layer stretch acrylic, single layer glass, two-wall cast acrylic, acrylic with Polyvinyl butyral (PVB) interlayer and glass with PVB interlayer) is considered and in each case the thickness which prevents the bird from perforating the windshield is calculated. Since helicopters can have lateral movement in addition to their longitudinal movement, the effect of incident angle on the integrity of windshield is also investigated. Simulations showed that among the five cases presented, glass with PVB interlayer can be the best choice for being used in windshield against bird strike. Another conclusion is that for the same initial velocity, the angled impact can cause more damage in the windshield than the direct impact.     

Improved Krill Algorithm for Reservoir Operation

Much of the world is facing water scarcity during one or the other part of the year. Hence, water resources management and optimal operation of water resources system take on added importance these days. This study introduces an improved version of krill algorithm for reservoir operation. The algorithm is based on adding an onlooker search mechanism to avoid being trapped in local optima and then updating its position. The new krill algorithm is tested using a case study for irrigation management. The computation time is 33 s for the new algorithm but is 54, 59, and 60 s for krill algorithm, particle swarm optimization and genetic algorithm, respectively. Also, the improved krill algorithm can meet 97% of irrigation demands and has the lowest value of vulnerability index among genetic algorithm, particle swarm optimization, and simple krill algorithm. Also, the average solution of improved krill algorithm is close to the global solution. Results indicate that the improved krill algorithm has high potential for application in water resource management.     

Sensitivity analysis of offset QAM multicarrier systems to residual carrier frequency and timing offsets

This paper presents a sensitivity analysis of filter bank multicarrier (FBMC) systems to carrier frequency offset (CFO) and timing offset. Although the emphasis of the paper is on the class of FBMC systems that are based on offset quadrature amplitude modulation (OQAM), the developed results are found applicable to cosine modulated-based FBMC systems as well. We assume that coarse CFO and timing offset estimations and compensations have already been performed so that the residual CFO and timing offset are small. A simple closed-form approximation to the signal-to-interference ratio (SIR) is derived. This approximation is compared numerically with the exact SIR and confirmed to be accurate for a variety of FBMC systems with different prototype filters. The derived SIR is characterized by a pair of coefficients that are only dependent on the underlying prototype filter, thus, allows the designer to pick from the choices of the prototype filter the one that has minimum sensitivity to CFO and/or timing offset.     

Ultrastructure of Felis catus whole fetus (Fcwf-4) cell culture following infection with feline coronavirus

Feline coronavirus (FCoV) consists of two biotypes based on their growth in cell culture and their antigenicity. Infections with FCoV are highly prevalent in the cat population worldwide. In this study, Felis catus whole fetus (Fcwf-4)cell culture was infected with FCoV UPM11C/08. Virus multiplication in cell culture was monitored and examined under the transmission electron microscope. The virus particles revealed the characteristic morphology of feline FCoV represented by envelope viruses surrounded by peplomers. Virus attachment and entry into the cell occurred 15?h post-infection (pi), and the myriad of virus particles were observed both extracellularly and intracellularly after 48?h pi. Thereafter, intracellular virus particles were observed to be present in vacuoles or present freely in the cytoplasm.     

Numerical Modeling of the Performance of Thermal Interface Materials in the Form of Paste-Coated Sheets

The performance of thermal interface materials in the form of core sheets coated on both sides with a thermal paste is numerically modeled by finite-element analysis. The paste is polyol-ester-based carbon black paste and serves to improve the conformability. Good agreement is found between modeling and experimental results that involve copper proximate surfaces sandwiching the thermal interface material. The core sheets are copper, aluminum, indium, and flexible graphite. Flexible graphite (made from exfoliated graphite) is advantageous in its low elastic modulus, whereas copper and aluminum foils are advantageous in their high thermal conductivity. Indium is advantageous in its low elastic modulus compared with copper or aluminum and in its high thermal conductivity compared with flexible graphite. Among the four types of core sheet with identical thickness, coated indium foil gives the best performance for the range of foil thickness of 6 μm to 112 μm for the case of smooth (0.01 μm roughness) proximate surfaces and 117 μm to 320 μm for the case of rough (15 μm roughness) proximate surfaces. Aluminum foil gives the best performance for the thickness range of 112 μm to 2000 μm in the case of smooth proximate surfaces. For thicknesses below these ranges, flexible graphite performs the best. For thicknesses above these ranges, copper foil performs the best.     

Investigation on some physicochemical properties of guest-conjugated and -incorporated hybrid organic/inorganic linear-dendritic nanocarriers

Benzyl alcohol, as a model compound in conjugation, and 1-(2-pyridylazo)-2-naphtol (PAN), as a lipophilic dye molecule in encapsulation, were exploited using linear-dendritic ABA amphiphilic triblock copolymers, which is known as “hybrid macromolecules”, containing silicon atoms by two methods. In the first route, benzyl alcohol was attached to the Si-Cl peripheral groups of the hybrid in different generations to synthesize host-benzyl alcohol conjugates. In the second procedure, PAN as the guest molecule was incorporated into different generations of the synthesized hybrid. Binding capacity and incorporation content (IC) of different generations of the hybrid were investigated using conventional methods such as nuclear magnetic resonance and UV–vis spectroscopy. It was observed that the IC, hydrolytic behavior and the release rate from the prepared micellar structures can be tuned by either external parameters such as pH or internal parameters such as hydrophilic/lipophilic ratio by developing generations. Dynamic light scattering and transmission electron microscopy experiments depicted diameter of the prepared nanocarriers between 100 to 250 nm. The release of guest molecules from the carriers was evaluated at pH 1, 7.4 and 10. Briefly, the prepared micelles can play a role as carrier with tunable release rate without sacrificing their micellar stability.     

Change Point Estimation Methods for Control Chart Postsignal Diagnostics: A Literature Review

Control charts are the most popular monitoring tools used to distinguish between special (assignable) and common causes of variation and to detect any changes in processes. The time that a control chart gives an out‐of‐control signal is not the real time of change. The actual time of the change is called the change point. Knowing the real time of the change will help and simplify finding the assignable causes of the signal, which may be the result of a shift in the process mean or change in process variability. This article gives an overview of change point estimation in control charts, provides a classification scheme, and describes the research that has previously appeared in the literature. In addition, a gap analysis in this area provides direction for future research. Copyright © 2011 John Wiley & Sons, Ltd.     

A green route for biodiesel production from waste cooking oil over base heterogeneous catalyst

The present work describes the synthesis of porous BaSnO₃ by eco‐friendly sol‐gel method using albumin as a bio‐template agent, and its application as a solid base catalyst in biodiesel production from waste cooking oil. The physico‐chemical, textural, and morphological properties of the catalyst were evaluated by X‐ray diffraction (XRD), Brunauer‐Emmett‐Teller (BET), field emission scanning electron microscopy (FESEM), and temperature programmed desorption (TPD)–CO₂ techniques. The synthesized catalyst showed considerable stability, efficient catalytic activity, and negligible metal leaching. The satisfactory performance of the catalyst could be ascribed to the presence of basic sites of different strength on the surface of the catalyst. The catalyst produced maximum biodiesel yield of 96% at optimum reaction conditions of 90°C reaction temperature, methanol to oil molar ratio of 10:1, catalyst dosage of 6 wt%, and reaction time of 2 hours. Moreover, the catalyst showed substantial reusability up to five reaction cycles without any considerable decrease in transesterification activity.