203 research outputs found
Investigating the Affected Factors on the Design of Display Case for Paper Work
Museum display cases are usually one of the most expensive parts in museum interior design and furniture; museum display cases are very special and have a lot of limitations in the selection of used materials. Usually, even the micrometer environment in museum shelves and display cases should be valuable in the primary control of a collection (1). The protected manuscripts in museums are particularly vulnerable in terms of vulnerability and difficulty in maintaining. The mechanisms of damage and preventive protection of these works and their changes over time depend entirely on environmental conditions (2). Display cases, as a means of protection, protect the works by increasing the security of the objects and confining them in an appropriate, stable and secure environment (3 and 4). In general, four main groups of factors cause damage to the manuscripts: 1- Physical factors 2- Chemical factors 3- Biological factors 4- Unexpected factors (5), each of which imposes specific requirements in the design and manufacture of display cases for protection. Due to the specific circumstances of these works, these requirements need to be collected and formulated in a purposeful way for the design of the display cases. This article has attempted to clarify what features each display case must have in order to be stable and to protect a manuscript by reviewing specialized texts, authoritative articles, and library resources. Finally, an example of an appropriate design based on the stated conditions is examined
Random assignments with uniform preferences: An impossibility result
Agents have uniform preferences if a weakly decreasing utility function determines each agent's preference ranking over the same order of alternatives. We show that the impossibility in the random assignment problem between strategyproofness, ordinally efficiency, and fairness in the sense of equal division lower bound, prevails even if agents have uniform preferences. Furthermore, it continues to hold even if we weaken the strategyproofness to upper-contour strategyproofness, or the ordinal efficiency to robust ex-post Pareto efficiency
Effect of operational parameters and internal recycle on rhenium solvent extraction from leach liquors using a mixer-settler
AbstractThe extraction of rhenium from molybdenite roasting dust leach solution was performed using a mixer-settler extractor by tributyl phosphate (TBP) diluted in kerosene as the extractant. In the single-stage extraction experiments, effect of the aqueous to organic phase ratios, Qa/Qo, and the number of extraction stages, N, on the rhenium extraction was studied. It was found that using the phase ratio of 1:1 in a two-stage extraction, 87.5% depletion of rhenium was obtained. The comparison of experimental results with the continuous co-current extraction showed a good agreement. The effect of internal recycle of organic phase was investigated in the phase ratio of 1:1 by changing the flow rate ratio of recycle-to-fresh organic phase, Qro/Qfo. The optimum performance was achieved in the phase ratio, Qro/Qfo, equal to 3:7. It was found that improvement in the performance of the mixer-settler for the rhenium-TBP system can be obtained in the phase ratio of 1:1when Qro/Qfo = 3:7
AN INTEGRATED MULTI-CRITERIA SCREENING FRAMEWORK TO ANALYZE FLEXIBILITY IN ENGINEERING SYSTEMS DESIGN: APPLICATIONS IN LNG INFRASTRUCTURES
Ph.DDOCTOR OF PHILOSOPH
Synthesis, Preparation and Antimicrobial Effects of Ag2S/PbSO4 Nanocomposites
The rapid and uncontrolled growth of microorganisms can lead to serious problems. With the development of nanotechnology over the last decade, golden opportunities have been created to discover the antibacterial effects of metallic nanoparticles. Metallic nanoparticles have an antibacterial effect, in addition to the inhibition effect of the particle, due to its small size, large surface area and large outer surface area. Scientists believe that nanoparticles can be used as appropriate alternative to used biochemicals.
Introduction: In the past two decades, the field of nanotechnology has grown exponentially since its birth and has made an immense impact on physical, chemical, earth and biological sciences. There has been an immense extension of nanomaterial applications and uses as a result of basic and applied research from scientists all over the world. One such class of nanomaterials are metal oxide (MeO) and metalsulfides (MeS) nanoparticles (NPs), ranging in size from 1 to 100 nm, available in different shapes and sizes.
Methods and Results: In this research, nanoparticles were first made in 1, 5 and 1.5 mg/l concentrations, then we study antimicrobial properties of nanoparticles by MIC methods and several gram-negative bacteria were examined for several nanostructures. 0.0064 g nanoparticles solved to prepare 100 cc of the medium, weigh the hinton broth 2.1 grams, and in another stock 7.6 g hinton agar in 200 cc water, Then we make microbial leachate from the tested microorganisms and compare with the half McFarland their turbidity, to the extent that they are half McFarland. Then, with a micropipette of 2.5 microns from the lagoon, remove the bacteria on the plates, and finally place the plates in the incubator for 24 hours, and the next day the results are read.
Conclusions: After making nanoparticles and investigating nanostructures on bacterial strains, we found that 32µg/ml of nanoparticles prevents the growth of bacteria in the control
Conformational changes of a chemically modified HRP
Horseradish peroxidase is an all alpha-Helical enzyme, which widely used in biochemistry applications mainly because of its ability to enhance the weak signals of target molecules. This monomeric heme-containing plant peroxidase is also used as a reagent for the organic synthesis, biotransformation, chemiluminescent assays, immunoassays, bioremediation, and treatment of wastewaters as well. Accordingly, enhancing stability and catalytic activity of this protein for biotechnological uses has been one of the important issues in the field of biological investigations in recent years. In this study, pH-induced structural alterations of native (HRP), and modified (MHRP) forms of Horseradish peroxidase have
been investigated. Based on the results, dramatic loss of the tertiary structure and also the enzymatic activity for both forms of enzymes recorded at pH values lower than 6 and higher than 8. Ellipticiy measurements, however, indicated very slight variations in the secondary structure for MHRP at pH 5. Spectroscopic analysis also
indicated that melting of the tertiary structure of MHRP at pH 5 starts at around 45° C, which is associated to the pKa of His 42 that has a serious role in keeping of the heme prostethic group in its native position through natural hydrogen bond network in the enzyme structure. According to our data, a molten globule like structure of a chemically modified form of Horseradish peroxidase at pH 5 with initial steps of conformational transition in tertiary structure with almost no changes in the secondary structure has been detected. Despite of some conformational changes in the tertiary structure of MHRP at pH 5, this modified form still keeps its catalytic activity to some extent besides enhanced thermal stability. These findings also indicated that a molten globular state does
not necessarily preclude efficient catalytic activity
Transactive Charging Management of Electric Vehicles in Office Buildings: A Dis-tributionally Robust Chance-Constrained Approach
Correlation between cortical state and locus coeruleus activity: Implications for sensory coding in rat barrel cortex
Cortical state modulates the background activity of cortical neurons, and their evoked response to sensory stimulation. Multiple mechanisms are involved in switching between cortical states including various neuromodulatory systems. Locus Coeruleus (LC) is one of the major neuromodulatory nuclei in the brainstem with widespread projections throughout the brain and modulates the activity of cells and networks. Here, we quantified the link between the LC spontaneous activity, cortical state and sensory processing in the rat vibrissal somatosensory “barrel” cortex (BC). We simultaneously recorded unit activity from LC and BC along with prefrontal electroencephalogram (EEG) while presenting brief whisker deflections under urethane anesthesia. The ratio of low to high frequency components of EEG (referred to as the L/H ratio) was employed to identify cortical state. We found that the spontaneous activity of LC units exhibited a negative correlation with the L/H ratio. Cross-correlation analysis revealed that changes in LC firing preceded changes in the cortical state: the correlation of the LC firing profile with the L/H ratio was maximal at an average lag of −1.2 s. We further quantified BC neuronal responses to whisker stimulation during the synchronized and desynchronized states. In the desynchronized state, BC neurons showed lower stimulus detection threshold, higher response fidelity, and shorter response latency. The most prominent change was observed in the late phase of BC evoked activity (100–400 ms post stimulus onset): almost every BC unit exhibited a greater late response during the desynchronized state. Categorization of the BC evoked responses based on LC activity (into high and low LC discharge rates) resulted in highly similar response profiles compared to categorization based on the cortical state (low and high L/H ratios). These findings provide evidence for the involvement of the LC neuromodulatory system in desynchronization of cortical state and the consequent enhancement of sensory coding efficiency
Robust feedback linearization control of air-feed system in PEM fuel cell against practical uncertainty
In this paper robust feedback linearization control approach based on the gap metric analysis is proposed to control a Proton Exchange Membrane Fuel Cell (PEMFC). The oxygen excess ratio ( ) is regulated through adjustment of the air supply to avoid oxygen starvation. Furthermore regulation improves the efficiency whilst more net power will be delivered. In this paper a six order state variable PEM fuel cell is used as a plant whereas the system variations and disturbances are regarded as uncertainties to configure the perturbed plant. The gap metric analysis is gained in this paper to assess the difference between the perturbed plants and that of the nominal. Results of using the nonlinear control law reveal that the proposed feedback linearization control is robust against disturbances during the oxygen excess ratio regulation.Results verify that the measurement delays in super twisting algorithm excite un-modeled dynamics because of higher frequency in the oscillations. The proposed controller eliminates influence of un-modeled dynamic and delay of actuator and sensor. Furthermore the designed controller is found capable to attenuate the practical measurement noise effect (in terms of a stochastic uncertainty) in both of the frequency spectrum and also in the overall amplitude
Signal Processing for Trace-based Anomaly Detection in Embedded Software
Embedded operating systems generate a log of operating system function calls which we refer to as traces. Trace-based anomaly detection deals with the problem of determining whether or not an instance of traces represents a normal execution scenario. Most current approaches focus on application areas outside of the embedded systems domain and thus do not take advantage of the intrinsic properties of this domain.
This work introduces Signal Processing for Trace Based Anomaly Detection (SiPTA): a novel technique for offline trace-based anomaly detection that utilizes the intrinsic feature of periodicity present in embedded systems. SiPTA uses discrete-time Fourier transform which is a crucial tool of signal processing theory as an underlying method. This Thesis describes a generic framework for mapping execution traces to channels and signals for further processing. The classification stage of SiPTA uses a comprehensive set of metrics. As this thesis demonstrates, SiPTA is particularly useful for embedded systems. More specifically, we will compare SiPTA with state-of-the-art approaches to trace-based anomaly detection based on the Markov Model and Neural Networks. This thesis also shows the technical feasibility and viability of SiPTA through multiple case studies using traces from a field-tested hexacopter, a mobile phone platform, and a car infotainment unit. In the experiments, our approach outperformed every other tested method
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