472 research outputs found

    Particle and Bacteria Sorting in Viscoelastic Fluids Using an Elasto-Inertia-Magnetic Fractionation Method

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    Detection of harmful biological substances in food at the Point of Use (PoU) is very important for the prevention of foodborne diseases. Sample and reagent preparation at the PoU, as a necessary step before detection, is urgently needed. Portable and field-deployable sample preparation microfluidic devices for manipulating particles and biological substances in water have been widely studied. During the recent years, more attention has been given to particles separation in non-Newtonian fluids due to their rheological similarity to the prominent fluids such as food (e.g. milk) and bodily fluids (e.g. blood). However, the mechanism of particle focusing and separation in non-Newtonian fluids is less understood, mainly due to the dominance of elastic forces in such flows. Accordingly, we developed a microfluidic device to investigate the effect of elastic, inertial, and magnetic forces on the focusing of magnetic (9 and 15 m) and non-magnetic (15 m) particles in synthetic viscoelastic fluids with various viscosities. The device included a square microchannel with a side permanent magnet, expanding symmetrically downstream to a wider channel to drop the particles velocity for on-chip imaging. We investigated the effect of multiple parameters on the focusing of each particle experimentally and analytically, in order to obtain physical understanding and the best recipe in which multiplex particle or bacteria separation could be achieved with high efficiency. The studied parameters included the microchannel cross-sectional size, flow rate, fluid viscoelasticity, and magnetic field strength and exposure time. We then used the results of the parametric study to perform Triplex-Inertia-Magneto-Elastic (TIME) sorting of magnetic and non-magnetic particles with >92% purity and efficiency. To demonstrate the potential use of this method in biological applications, we immunologically conjugated two types of bacteria to magnetic and non-magnetic particles and separated them from each other in the microfluidic device with a purity and efficiency of >99%. This study provides the foundation for development of devices for separation of bio-substances in viscoelastic fluids, immunologically attached to microparticles. Our device has the potential to be used for on-site sample preparation along with a variety of biosensors to render biodetection possible at the PoU

    Damage Diagnosis of Structures Using Modal Data and Static Response

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    This paper is aimed at presenting three methods to detect and estimate damage using modal data and static response of a damaged structure. The proposed methods use modal data with and without noise or static displacement to formulate objective functions. Damage location and severity in structural elements are determined using optimization of the objective functions by the simulated annealing algorithm. These methods have been applied to three examples, namely a three-story plane frame, cantilever plate and benchmark problem provided by the IASC-ASCE Task Group on Structural Health Monitoring. Also, the effect of the discrepancy in mass and stiffness between the finite element model and the actual tested system has been investigated. The obtained results indicate that the proposed methods can be viewed as a powerful and reliable method for structural damage detection and estimation

    Study on corrosion protection of organic coatings using electrochemical techniques: developing electrochemical noise method, effective of surface preparation and inhomogeneity of organic coatings

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    This study looks into two important aspects of corrosion protection of steel by organic coatings, steel surface preparation and ionic conduction through the coating, as well as development of the electrochemical noise method as an effective assessment method. Surprising and somehow controversial previous findings at the University of Northampton showed an inverse relationship between the roughness of metal substrate and performance of paint coating. So this study was initially launched to further study the effect of metal surface preparation. Four conventional surface preparation methods including ultra high pressure (UHP) hydroblasting, wet abrasive blasting, acid pickling and emery abrasion were studied and compared to an as received control surface. A particular interest of this work was the high demand for an environmentally friendly surface preparation method, e.g. as afforded by UHP hydroblasting, to replace the traditional wet abrasive blasting method. Results of this study revealed the important role of the innate native oxide film and the deleterious effect of contaminants on the protective performance of organic coating. Also it was shown that a highly active surface and large surface profile can be deleterious if an appropriate interaction between paint and metal is not achieved. Results of this study confirmed the earlier findings and suggested the UHP hydroblasting is a successful, cost effective and environmentally friendly surface preparation method and a modern replacement for wet abrasive blasting method. In addition to the effectiveness of metal surface preparation, the ability of organic coating in preventing ions access to metal plays an equally important role in defining the anti-corrosion performance of a coated metal. Hence the mechanism of ionic conduction through organic coatings and their inhomogeneity which are normally formed in crosslinking systems was extensively studied with the aim of finding the cause of formation of the more permeable areas and the ways by which they can be prevented. Several structural and environmental parameters were examined including the coating thickness, multi-layer paint application, curing temperature, partially non-functional resin, pigmentation and solvent. Experimental results showed that the solvent degree to which can escape, the non-functional polymer parts and inherently hydrophilic functional groups of organic coatings are the main parameters causing inhomogeneity and highly ion permeable areas. A statistical model was also developed that can be used to estimate number of permeable areas or corrosion initiation sites in a large area of coating. A particular concern of this work throughout the entire study was development of the electrochemical noise measurement (ENM) in the sense of a good assessing technique for protection efficiency of a coating system. Previous studies have shown great potential of ENM as a practical technique in the field. However, the technique always involved measuring the electrochemical noise between two or three isolated electrodes which cannot be easily provided in certain applications such as submerged structures or inside storage tanks. Also involvement of two or three electrodes in the measurement induces an ambiguity in regards to which electrode dominates the result. Here an attempt was made to perform the noise measurement on a single working electrode so that it can be used in more practical situations. Preliminary results indicate this approach holds promise

    Developing a Smart Proxy for Predicting the Fluid Dynamic in DamBreak Flow Simulation by Using Artificial Intelligence

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    Multiphase flow simulations are essential methods for providing information such as the evolution of phase fraction (gas, liquid and solid), velocities, pressure, temperature and flow regimes at every time during a process. Dynamic flow simulations also help reservoir, drilling, and production engineers to develop a proper well design. DamBreak problem is one of the most well-known problems in computational fluid dynamics (CFD); it is a dynamic hydraulic phenomena and the numerical simulation requires sophisticated mathematical modeling. OpenFOAM, is used to run CFD simulations in this thesis.;One of the main issues in CFD is that the simulations are time-consuming. In this work, will use artificial intelligence (AI) to predict the behavior of the system at each time-step of the process at a lower run time. DamBreak problem is defined base on a two-dimensional rectangular tank with a barrier at the bottom, the liquid column (water in this study) at the left side of the tank behind the wall. As soon as the wall collapse, the water will pour down, resulting in complicated fluid dynamics. The main data-set, generated by OpenFOAM flow simulations, is used for building the smart proxy model (SPM), using the network toolbox in MATLAB. Neural network (NN) is applied with feed-forward back propagation method and the training algorithm is Levenberg Marquardt.;Results indicate that the smart proxy can run 3 seconds of the DamBreak process, which takes 8 hours of computational time with 4 processors when is done by using OpenFOAM, takes less than 2 minutes using the developed SPM on one processor. SPM is also capable of predicting the CFD results in non-cascading condition and up to around 40 time-steps in cascading condition with acceptable error (less than %10)

    Report on Establishing Telemedicine Services in Iran

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    The speed of technological changes, the advent of new innovations, and the increasing competition have made the use of new technologies as the focus of the business firms and government. Information technology has had a great impact on health as one of the areas in human social life by forming the information societies. Currently, all the health care processes are highly depending on technology. Whereas its management, transmission, the distance elimination, the diagnosis speed, and the disease treatment are necessary issues. These two major subjects have led to the formation of a new branch in medical sciences called telemedicine technology. Considering numerous advantages of telemedicine technology, the necessity of applying this technology in developing countries, including our country- Iran- is inevitable (1). Providing telemedicine healthcare services essentially involves extensive implications in both ICT and medical services. The range of these concepts is so broad that it may be probable to consider telemedicine as a cultural issue applying the features of communication concepts in health care offer, beyond considering it as a service. It is necessary to a simple telephone communication to establish a psychotherapeutic service, to use smart agents in a trans-continental relationship, using vital signs and various medical images to identify and even treat a patient (2). Remote patient monitoring or telemedicine provides appropriate solutions in urgent medical assistance, long distance monitoring, the management and logistics, the quality assurance and supervision, as well as preparation and training of health care professionals. Telemedicine plays an important role even in the fight against communicable diseases, as well as in helping injured people in disasters and accidents (2,5). Telemedicine has been most beneficial to various healthcare services in some countries, particularly in developing countries such as Iran which faces unbalanced distribution of resources and specialists in various fields of medical sciences, and to make it available in all over the country. Telemedicine services provide the opportunity to improve both the quality and the availability of health care services regardless of the geographical limitations. These services also present numerous socio-economic benefits considering the significant return of resources to investors, service providers and equipment providers can be highly effective in optimizing the use of existing financial and human facilities and resources (7,6). Telemedicine requires careful planning and precise management to perform and develop the goals. Therefore, to achieve the above-mentioned objectives and using telemedicine in a large scale, it is required to evaluate the problems and the performance of this system periodically by planning and making useful changes to overcome them and thereby improve the status quo. Although remote patient monitoring or telemedicine services have great potentials and provide significant long-term benefits to the healthcare system, especially in a country such as Iran that it’s not possible to uniformly distribute power and health services in all areas, the optimal use of this system requires the provision of resources and essential infrastructures in addition to resolve the problems and eliminating the shortcomings. It is also worth noting that for the useful and continuous application of this system, the geographical facilities and limitations of each satellite center should be considered as the reference when deciding to provide the necessary infrastructure. To increase the efficiency and purpose of this system, it is better to first investigate the requirements and shortages of each region in the fields of medical specialties as well as the prevalent diseases and health problems of the region, considering which disease and consultation with which of the specialized and technical services are considered. Besides, due to the recent advent of telemedicine consultation system in our country's health care system and its failure to implement routinely as a result of the inadequate acceptance by physicians, and the consulting hospitals' personnel, it is better to select the satellite centers ensured that there were sufficient psychological acceptance and the willingness to cooperate in the project and to prevent the imposition of this system on recipient counseling centers, which has a deterrent role in helping physicians and nurses work together to advance this plan. In the end, it is necessary to spend sufficient funds and using experiences obtained from the present plan, increasing the number and quality of this type of counseling to be more accurate than the evaluation of the medical consulting system, especially in terms of cost-effectiveness

    The Application of PSO in Structural Damage Detection: An Analysis of the Previously Released Publications (2005–2020)

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    The structural health monitoring (SHM) approach plays a key role not only in structural engineering but also in other various engineering disciplines by evaluating the safety and performance monitoring of the structures. The structural damage detection methods could be regarded as the core of SHM strategies. That is because the early detection of the damages and measures to be taken to repair and replace the damaged members with healthy ones could lead to economic advantages and would prevent human disasters. The optimization-based methods are one of the most popular techniques for damage detection. Using these methods, an objective function is minimized by an optimization algorithm during an iterative procedure. The performance of optimization algorithms has a significant impact on the accuracy of damage identification methodology. Hence, a wide variety of algorithms are employed to address optimization-based damage detection problems. Among different algorithms, the particle swarm optimization (PSO) approach has been of the most popular ones. PSO was initially proposed by Kennedy and Eberhart in 1995, and different variants were developed to improve its performance. This work investigates the objectives, methodologies, and results obtained by over 50 studies (2005-2020) in the context of the structural damage detection using PSO and its variants. Then, several important open research questions are highlighted. The paper also provides insights on the frequently used methodologies based on PSO, the computational time, and the accuracy of the existing methodologies

    Principles and essentials of strategic decisions

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    Decision making is one of the processes which managers are constantly dealing with. Inseparability of management from decision making is to the extent that both issues are known as each other’s synonym. In the matter of decision making, the important point is that most managers are unable to analyze their decisions and consider it as a static and not a dynamic activity. Considering this and given the importance and role of strategic decisions in an organization’s success or failure, in this study, first we are going to explain the concept of decision making and its characteristics, thoughts and opinions about it, and then to study the principles and essentials of strategic decision making and general aspects of the views stated in this regard

    Principles and essentials of strategic decisions

    Get PDF
    Decision making is one of the processes which managers are constantly dealing with. Inseparability of management from decision making is to the extent that both issues are known as each other’s synonym. In the matter of decision making, the important point is that most managers are unable to analyze their decisions and consider it as a static and not a dynamic activity. Considering this and given the importance and role of strategic decisions in an organization’s success or failure, in this study, first we are going to explain the concept of decision making and its characteristics, thoughts and opinions about it, and then to study the principles and essentials of strategic decision making and general aspects of the views stated in this regard
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