230 research outputs found
Realization of Low-Voltage Modified CBTA and Design of Cascadable Current-Mode All-Pass Filter
In this paper, a low voltage modified current backward transconductance amplifier (MCBTA) and a novel first-order current-mode (CM) all-pass filter are presented. The MCBTA can operate with ±0.9 V supply voltage and the total power consumption of MCBTA is 1.27 mW. The presented all-pass filter employs single MCBTA, a grounded resistor and a grounded capacitor. The circuit possesses low input and high output impedances which make it ideal for current-mode systems. The presented all-pass filter circuit can be made electronically tunable due to the bias current of the MCBTA. Non-ideal study along with simulation results are given for validation purpose. Further, an nth-order cascadable all-pass filter is also presented. It uses n MCBTAs, n grounded resistors and n grounded capacitors. The performance of the proposed circuits is demonstrated by using PSPICE simulations based on the 0.18 µm TSMC level-7 CMOS technology parameters
Current and Voltage Mode Multiphase Sinusoidal Oscillators Using CBTAs
Current-mode (CM) and voltage-mode (VM) multiphase sinusoidal oscillator (MSO) structures using current backward transconductance amplifier (CBTA) are proposed. The proposed oscillators can generate n current or voltage signals (n being even or odd) equally spaced in phase. n+1 CBTAs, n grounded capacitors and a grounded resistor are used for nth-state oscillator. The oscillation frequency can be independently controlled through transconductance (gm) of the CBTAs which are adjustable via their bias currents. The effects caused by the non-ideality of the CBTA on the oscillation frequency and condition have been analyzed. The performance of the proposed circuits is demonstrated on third-stage and fifth-stage MSOs by using PSPICE simulations based on the 0.25 µm TSMC level-7 CMOS technology parameters
Lossy/Lossless Floating/Grounded Inductance Simulation Using One DDCC
In this work, we present new topologies for realizing one lossless grounded inductor and two floating, one lossless and one lossy, inductors employing a single differential difference current conveyor (DDCC) and a minimum number of passive components, two resistors, and one grounded capacitor. The floating inductors are based on ordinary dual-output differential difference current conveyor (DO-DDCC) while the grounded lossless inductor is based one a modified dual-output differential difference current conveyor (MDO-DDCC). The proposed lossless floating inductor is obtained from the lossy one by employing a negative impedance converter (NIC). The non-ideality effects of the active element on the simulated inductors are investigated. To demonstrate the performance of the proposed grounded inductance simulator as an example, it is used to construct a parallel resonant circuit. SPICE simulation results are given to confirm the theoretical analysis
Talent and student private rented sector bottlenecks: a preliminary UK investigation
Purpose – The purpose of this paper is to sketch the UK housing backdrop, review the student private rented sector (PRS) and assess the experience of post-graduate university student tenants in the PRS.
Design/methodology/approach – A literature review puts the issues of student-PRS
responsiveness into context and helps to untangle some UK housing issues. The private sector’s size, growth and performance is assessed by reviewing secondary data. In-depth interviews were then conducted at a regional university campus.
Findings – The study confirms accumulating evidence of an unbalanced UK housing market. The study identified four main PRS issues: first, rapid university expansion without accompanying residential construction has sparked rampant PRS growth with, second, quality issues, third, in tight letting market conditions, rented agent service levels fell and fourth, part of the problem is complex PRS management procedures.
Research limitations/implications – The research has three noteworthy limitations. First, the macroeconomic analysis integrated secondary research without independent modelling. Second, the views of letting agents, university property managers, planning officers or landlords were not canvassed. Finally, the pilot interviews were geographically restricted.
Practical implications – When they expand, universities, local authorities and industry players need to give due consideration to plan for, design and develop quality student accommodation. Over-reliance on the PRS without informed oversight and coordination could undermine student experience and erode long-term UK competitiveness.
Social implications – The lack of quality student rented accommodation mirrors a general housing malaise around affordability, polarisation and sustainable “dwelling”. Standards and professionalism in the rented sector is part of the overall quality mix to attract global talent.
Originality/value – The preliminary investigation uses mixed-methods to investigate PRS service delivery. It illustrates the interplay between professional property management and wider issues of metropolitan productivity, sustainability and resilience
Comparison of mathematical models and artificial neural networks for prediction of drying kinetics of mushroom in microwave vacuum dryer
Drying characteristics of button mushroom slices were determined using microwave vacuum drier at various powers (130, 260, 380, 450 W) and absolute pressures (200, 400, 600, 800 mbar). To select a suitable mathematical model, 6 thin-layer drying models were fitted to the experimental data. The fitting rates of models were assessed based on three parameters; highest R2, lowest chi square () and root mean square error (RMSE). In addition, using the experimental data, an ANN trained by standard back-propagation algorithm, was developed in order to predict moisture ratio (MR) and drying rate (DR) values based on the three input variables (drying time, absolute pressure, microwave power). Different activation functions and several rules were used to assess percentage error between the desired and the predicted values. According to our findings, Midilli et al. model showed a reasonable fitting with experimental data. While, the ANN model showed its high capability to predict the MR and DR quite well with determination coefficients (R2) of 0.9991, 0.9995 and 0.9996 for training, validation and testing, respectively. Furthermore, their predictions Mean Square Error were 0.00086, 0.00042 and 0.00052, respectively
All-Pass Sections with High Gain Opportunity
In this paper, two new circuits for realizing firstorder voltage-mode (VM) all-pass section (APS) with variable gain are presented. The first proposed filter uses a single differential difference current conveyor (DDCC), one grounded capacitor and three resistors. The second proposed filter consists of two DDCCs, three grounded resistors and one grounded capacitor. It provides highinput and low-output impedances and can provide high gain. Both of the proposed circuits do not require any element matching condition. Moreover, oscillator circuits with minimum number of active and passive elements are derived from the proposed APSs. The proposed circuits are tested experimentally or by simulation using SPICE program to confirm the theory
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A model-based comparison of three theories of audiovisual temporal recalibration
Observers change their audio-visual timing judgements after exposure to asynchronous audiovisual signals. The mechanism underlying this temporal recalibration is currently debated. Three broad explanations have been suggested. According to the first, the time it takes for sensory signals to propagate through the brain has changed. The second explanation suggests that decisional criteria used to interpret signal timing have changed, but not time perception itself. A final possibility is that a population of neurones collectively encode relative times, and that exposure to a repeated timing relationship alters the balance of responses in this population. Here, we simplified each of these explanations to its core features in order to produce three corresponding six-parameter models, which generate contrasting patterns of predictions about how simultaneity judgements should vary across four adaptation conditions: No adaptation, synchronous adaptation, and auditory leading/lagging adaptation. We tested model predictions by fitting data from all four conditions simultaneously, in order to assess which model/explanation best described the complete pattern of results. The latency-shift and criterion-change models were better able to explain results for our sample as a whole. The population-code model did, however, account for improved performance following adaptation to a synchronous adapter, and best described the results of a subset of observers who reported least instances of synchrony
In vivo evaluation of the combination effect of near-infrared laser and 5-fluorouracil-loaded PLGA-coated magnetite nanographene oxide
Magnetite nanographene oxide has exhibited great potential in drug delivery and photothermal therapy (PTT) for cancer treatment. Here we developed 5-fluorouracil-loaded poly (lactic-co-glycolic acid)-coated magnetite nanographene oxide (NGO-SPION-PLGA-5-Fu) to simplify combined PTT and chemotherapy in one complex. The nanocarrier was synthesized using a modified O1/W1/O2/W2 multiple emulsion solvent evaporation method and was characterized for size, zeta potential, drug loading, in vitro and in vivo release. In this paper, in vivo suppression effect of PTT and chemotherapy using this synthesized magnetite nanographene oxide was studied. The in vitro release of 5-Fu from nanoparticles showed that 41.36 of the drug was released within 24�h. In vivo release showed that 5-Fu has a sustained release profile and prolonged lifetime in the rabbit plasma. Remarkably, a single injection of NGO-SPION-PLGA-5-Fu and 808�nm near-infrared laser (NIR) irradiation for 3�min effectively suppressed the growth of tumours compared with 5-Fu alone (p�<�.01). Magnetic resonance imaging (MRI) confirmed that the magnetic nanographene oxide was effectively targeted to the tumour site. Therefore, NGO-SPION-PLGA-5-Fu showed excellent PTT efficacy, magnetic targeting property, and MRI ability, indicating that there is a great potential of NGO-SPION-PLGA-5-Fu for cancer theranostic applications. © 2018 Informa UK Limited, trading as Taylor & Francis Grou
The first report of the genus and species of Florithrips traegardhi (Thysa.: Thripidae) from Iran
A faunistic study of the order Thysanoptera was conducted in cereal crop fields of the southwestern Iranian province of Khuzestan during 2007-2009. The species Florithrips traegardhi (Trybom) was collected from various grasses including corn, rice and wheat and later found its genus and species are new records for Iran
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