Full W-band MMIC medium power amplifier

A full W-band, MMIC amplifier has been tested on-wafer. The chip delivers 25-43 mW with 6.2±1.2 dB associated large-signal gain across 75-110 GHz when input power is held constant at 8 mW. This is the widest bandwidth MMIC amplifier ever published that delivers at least 25 mW over the entire W-band

Empirical load-line capacitance models for HEMT

Models for describing the gate-source and gate-drain capacitances' variation along a resistive load line have been proposed. They are charge conservative and consistent with the small-signal model at bias points along the load line. The extraction procedure for the models' parameters is fast and intuitive. The models can be implemented easily in most circuit simulator programs

Novel technique of phase velocity equalization for microstrip coupled-line phase shifters

By properly selecting the characteristic impedance and electrical length of the linking line between the coupled lines, phase velocity compensation for microstrip coupled-line phase shifters can be achieved. This technique does not introduce extra element or modification to the coupling in the main coupled lines. It is simple to implement and it has the potential to be used at mm-wave frequencies

Testing Alternative Theories of the Property Price-Trading Volume Correlation

This article examines the correlation between the real housing price and trading volume. Contrary to the predictions of standard rational expectation models, a robust positive correlation between the two variables is identified. While no clear lead-lag relationship is found in the raw data, which is more consistent with the downpayment effect model, the medium-run component of the trading volume tends to lead (and Granger cause) the corresponding component of the property price, which is more consistent with the search theoretic model. An explanation for this difference in behavior is suggested and several future research directions are provided.

Physically-Realizable Uniform Temperature Boundary Condition Specification on a Wall of an Enclosure: Part II – Problem Solution

Temperature measurements along one side of the rectangular plate showed severe temperature non-uniformity along one side of a wall of a cubical experimental apparatus where the uniform temperature was physically desired. Despite proper planning and analyses, this non-uniformity was high enough that a benchmark study could not be carried out to the desired accuracy of about one percent error. This paper presents and extends analyses made previously based on the modifications to the original design of the apparatus to reduce the temperature non-uniformity on the wall by adding an auxiliary heater around a wall where the uniform temperature was desired. A detailed mathematical analysis shows significant reduction in temperature non-uniformity from about four percent (based on the initial design) to less than one percent (for the modified design). By examining the temperature difference between two locations on the plate, the predicted temperature difference obtained through mathematical analyses show excellent agreement with the measured temperature difference. The temperature non-uniformity along the boundary of a wall was reduced to less than one percent of the overall temperature difference

Physically-Realizable Uniform Temperature Boundary Condition Specification on a Wall of an Enclosure: Part I – Problem Investigation

Designing an experimental apparatus requires considerable amount of planning. Despite proper planning, one can easily overlook a design such as the standard uniform temperature boundary condition applied to all or portion of a wall of an experimental apparatus. Although this boundary condition is mathematically simple and precise, achieving it physically may not be that simple. This paper addresses one such three-dimensional natural convection heat transfer apparatus that was designed to measure benchmark Nusselt numbers at various Rayleigh numbers with uniform temperatures specified at two walls of the enclosure. It was found that the effect of thermal spreading/constriction resistance on one wall where this uniform temperature condition was prescribed was significant, and as a result, the uniform temperature profile based on the initial design was not physically achieved. In support of this non-uniform temperature observation, this paper presents a thermal resistance model of a plate (which is a portion of this overall heat transfer apparatus) to explain the observed temperature non-uniformity. The results obtained from the current model are validated with measured data, and in terms of a temperature difference between two locations on the plate, the approximate analytical solution is well within the experimental error of 0.03K

Internet of Things (IoT) enabled water monitoring system

Water is always a crucial part of everyday life. Due to global environmental situation, water management and conservation is vital for human survival. In recent times, there were huge needs of consumer based humanitarian projects that could be rapidly developed using Internet of Things (IoT) technology. In this paper, we propose an IoT based water monitoring system that measures water level in real-time. Our prototype is based on idea that the level of the water can be very important parameter when it comes to the flood occurrences especially in disaster prone areas. A water level sensor is used to detect the desired parameter, and if the water level reaches the parameter, the signal will be feed in realtime to social network like Twitter. A cloud server was configured as data repository. The measurement of the water levels are displayed in remote dashboard

Processing of strong flux trapping high T(subc) oxide superconductors: Center director's discretionary fund

Magnetic suspension effect was first observed in samples of YBa2Cu3O7/AgO(Y-123/AgO) composites. Magnetization measurements of these samples show a much larger hysteresis which corresponds to a large critical current density. In addition to the Y-123AgO composites, recently similar suspension effects in other RE-123/AgO, where RE stands for rare-Earth elements, were also observed. Some samples exhibit even stronger flux pinning than that of the Y-123/AgO sample. An interesting observation was that in order to form the composite which exhibits strong flux trapping effect the sintering temperature depends on the particular RE-123 compound used. The paper presents the detailed processing conditions for the formation of these RE-123/AgO composites, as well as the magnetization and critical field data

Synergistic co-cultivation of activated sludge and microalgae in enhancing lipid production and N-laden wastewater treatment

The influence of inoculation ratios of activated sludge and microalgae were investigated in this study in the aspects of biomass yield, lipid yield and total nitrogen (TN) removal efficiency. It was observed that mixed culture of activated sludge/microalgae with the ratio 1:1 and 1:0.75 achieved a maximum lipid production up to 0.144 g/L and 0.133 g/L as compared with microalgae culture alone, which was only 0.081 g/L. The highest total nitrogen (TN) removal was observed with 1:1 and 1:0.75 ratios of activated sludge/microalgae cultures ranging from 96.3-96.9% removal efficiency, which was an improvement of about 90% removal efficiency compared to the activated sludge culture (6.25±0.08%). The flocculation efficiency was generally improved in mixed cultures of activated sludge andmicroalgae in comparison with only activated sludge culture and microalgae culture alone.Keywords: activated sludge; microalgae; co-cultivation; lipid; nitrogen removal

Empirical load-line capacitance models for HEMT

Models for describing the gate-source and gate-drain capacitances' variation along a resistive load line have been proposed. They are charge conservative and consistent with the small-signal model at bias points along the load line. The extraction procedure for the models' parameters is fast and intuitive. The models can be implemented easily in most circuit simulator programs