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Purpose: This article reports the clinical outcomes observed in a large number of patients receiving block bone allograft used for sinus augmentation and delayed implant placement. Patients and Methods: In total, 28 patients (13 males) with a mean age of 49.8 ±10.1 years (range: 33‑67 years) were included in this case series. All selected patients suffered from severe alveolar ridge atrophy in the posterior maxilla and required bone augmentation procedures, followed by implant placement after 6 months. All patients were followed for 18 months after the grafting, with scheduled monthly visits and/or more frequent visits if required. The survival rates for both the bone blocks and placed implants were then evaluated. Results: A total of 42 blocks and 90 implants were placed. Only one bone graft and 5 implants failed; the survival rate was 97.2% and 95.5% for the bone grafts and implants, respectively. The graft failed due to the onset of post‑surgical infectious sinusitis, while in some patients’ implants showed absence of osteointegration at the end of the healing phase. Of note, all failed implants were observed in heavy smokers; in all other patients, blocks and implants were successful. Conclusions: This preliminary case series suggests that the grafting of bone allograft followed by delayed implant placement may be a promising strategy for sinus augmentation. More extended and larger follow‑up studies are needed to confirm this preliminary data. [ABSTRACT FROM AUTHOR]

In this paper, a new thermal model based on the Fourier series solution of heat conduction equation has been introduced in detail. 1-D and 2-D Fourier series thermal models have been programmed in MATLAB/Simulink. Compared with the traditional finite-difference thermal model and equivalent RC thermal network, the new thermal model can provide high simulation speed with high accuracy, which has been proved to be more favorable in dynamic thermal characterization on power semiconductor switches. The complete electrothermal simulation models of insulated gate bipolar transistor (IGBT) and power diodes under inductive load switching condition have been successfully implemented in MATLAB/Simulink. The experimental results on IGBT and power diodes with clamped inductive load switching tests have verified the new electrothermal simulation model. The advantage of Fourier series thermal model over widely used equivalent RC thermal network in dynamic thermal characterization has also been validated by the measured junction temperature. [ABSTRACT FROM AUTHOR]

The requirements for driving gallium nitride (GaN) heterostructure field-effect transistors (HFETs) and the design of a resonant drive circuit for GaN power HFET switches are discussed in this paper. The use of wideband III-nitride (such as GaN) devices today is limited to telecom and low-power applications. The current lack of high-frequency high-power drivers prevents their application in power converters. The proposed circuit is based upon resonant switching transition techniques, by means of an LC tag, to recover part of the power back into the voltage source in order to reduce the power loss. This circuit also uses level shifters to generate the zero and negative gate-source voltages required to turn the GaN HFET on and off, and it is highly tolerant to input-signal timing variances. The circuit reduces the overall power consumed in the driver and thus reduces the power loss. This is particularly important for high-frequency driver operation to take full advantage, in terms of efficiency, of the superior switching speed of GaN devices. In this paper, the topology of the low-power-loss high-speed drive circuit is introduced. Some simulation results and preliminary experimental measurements are discussed. [ABSTRACT FROM AUTHOR]

Although insulated-gate bipolar-transistor (IGBT) turn-on losses can be comparable to turn-off losses, IGBT turn-on has not been as thoroughly studied in the literature. In the present work IGBT turn on under resistive and inductive load conditions is studied in detail through experiments, finite element simulations, and circuit simulations using physics-based semiconductor models. Under resistive load conditions, it is critical to accurately model the conductivity-modulation phenomenon. Under clamped inductive load conditions at turn-on there is strong interaction between the IGBT and the freewheeling diode undergoing reverse recovery. Physics-based IGBT and diode models are used that have been proved accurate in the simulation of IGBT turn-off. [ABSTRACT FROM AUTHOR]

This paper presents the application of compact insulated gate bipolar transistor and p-i-n diode models, including features such as local lifetime control and field-stop technology, to the full electrothermal system simulation of a hybrid electric vehicle converter using a lookup table of device losses. The vehicle converter is simulated with an urban driving cycle (the Federal Urban Driving Schedule), which is used to generate transient device temperature profiles. A methodology is also described to explore the converter reliability using the temperature profile, with rainflow cycle counting techniques from material fatigue analysis. The effects of ambient temperature, driving style, and converter design on converter reliability are also investigated. [ABSTRACT FROM AUTHOR]

Intraoral bone defects may be treated using autologous grafts, homologous grafts, heterologous grafts or synthetic products. Autologous bone is now considered the gold standard for bone grafting procedures. Homologous fresh frozen bone, provided by bone banks, is frequently utilized by orthopaedic surgeons because it is considered a safe material from immunological and viral points of view.In the cases reported here, homologous bone was used to repair some osseous defects without changing the surgical protocol utilized for autologous bone procedures. The main advantages of this strategy are low morbidity, shorter surgical times, more comfort and less risk of infection for the patient as well as the greater availability of bone. [ABSTRACT FROM AUTHOR]

In this paper, a parameter extraction procedure for high-voltage diodes with local lifetime control is proposed. It is designed for use with the physics-based diode model described in Part I, which is capable of simulating diodes with local lifetime control. The parameter extraction procedure described requires a forward characteristic and a reverse recovery measurement. The parameter extraction procedure is illustrated using finite-element simulations. The physics-based model using the parameters extracted is then compared with experimental results. [ABSTRACT FROM AUTHOR]

This paper presents the development and implementation of a physics-based diode model which can simulate aspects of high-voltage diodes such as snappy recovery during punch-through and the modified carrier density profile due to local lifetime control. It uses a Fourier series solution for the ambipolar diffusion equation in the lightly doped base region. The model is compared with finite-element device simulations. A parameter extraction procedure for the diode with lifetime control is proposed in Part II. [ABSTRACT FROM AUTHOR]

Recently, a simulation method for power electronic devices has emerged, which has high accuracy and short run times based on a Fourier model of the devices physics. This paper describes the use of the Fourier models for diodes and insulated gate bipolar transistors (IGBTs) and implementation in MATLAB and Simulink in a formal optimization strategy. In particular, this paper investigates coupled circuit, diode, and IGBT behavior. Conclusions are drawn concerning device loading and circuit design, particularly the role stray inductance. [ABSTRACT FROM AUTHOR]

This paper presents a practical destruction-free parameter-extraction methodology for a new physics-based circuit simulator buffer-layer integrated gate-commutated thyristor (IGCT) model. Most key parameters needed for this model can be extracted by one simple clamped inductive-load switching experiment. To validate this extraction method, a clamped inductive-load switching experiment was performed, and corresponding simulations were carried out by employing the IGCT model with parameters extracted through the presented methodology. Good agreement has been obtained between the experimental data and simulation results. [ABSTRACT FROM AUTHOR]

A practical and accurate parameter extraction method is presented for the Fourier-based-solution physics-based insulated gate bipolar transistor (IGBT) and power diode models. The goal is to obtain a model accurate enough to allow switching loss prediction under a variety of operating conditions. In the first step of the extraction procedure, only one simple clamped inductive load test is needed for the extraction of the six parameters required for the diode model and of the 12 and 15 parameters required for the nonpunch-through (NPT) and punch-through (PT) IGBT models, respectively. The second part of the extraction procedure is an automated formal optimization step that refines the parameter estimation. Validation with experimental results from various structures of IGBT demonstrates the accuracy of the proposed IGBT and diode models and the robustness of the parameter extraction method. [ABSTRACT FROM AUTHOR]

The integration of a series active filter with a 12-pulse diode rectifier can provide a cost-effective and efficient means of supply current harmonic-free ac/dc conversion. Controlling the series active filter as a frequency-selective impedance requires low delays and is not well suited for digital control. This paper suggests a current-mode control strategy to allow full digital control of the active filter. The suggested current-mode control method for supply current balancing and voltage regulation is verified experimentally. [ABSTRACT FROM AUTHOR]

Presents a study that examined circuit simulator models for the diode and insulated gate bipolar transistor (IGBT) with full temperature dependent features. Simulation of the distributed charge; Results of the study; Conclusion.

Presents a study which developed an electrothermal physics-based model for the field-stop insulated gate bipolar transistor. Characteristics of the model; Analytical description of the field-stop layer; Details of the experimental and simulation results.

Presents a method of rapid prototyping of digital controls for power electronics. Virtual test bed (VTB) environment; Proposed design approach; Co-simulation between VTB and Matlab/Simulink.

Presents information on a study that assessed wide bandgap semiconductors for power devices. Optimal semiconductor materials; Critical electric field and bandgap energy; Specific on-resistance calculation and comparison.

Presents a study which proposed a discontinuous conduction mode electronic ballast topology as solution to the problem regarding the radiated noise created by the high frequency current flowing through the fluorescent lamp. Information on the three different types of ballasts; Description of the proposed topology; Conclusion.

Flow boiling with dielectric coolant is not only a highly desirable approach for effective electronic cooling but is also notorious for its poor scalability. Most current flow boiling enhancement strategies are based on silicon substrates with footprint areas less than 1 cm2, which greatly limits their applications to large-size electronics. This study developed a scalable channel configuration to facilitate efficient flow boiling on large copper substrates (∼10 cm2), in which the channel walls are formed by porous pin-fin arrays. This type of hybrid capillary wall makes up for the limitation of conventional machining in creating intricate features, making it scalable and feasible for developing large-size, two-phase cold plates. Moreover, effective two-phase separation and sustainable film evaporation have been realized in the current work. As a result, the proposed structure achieved a 512% increase in heat dissipation when the heating area scales up 480% from the silicon microchannels with micro-pin-fin arrays. Experiments showed a base heat flux of 106.1 W/cm2 was dissipated over a heating area of 9.6 cm2 using the dielectric fluid HFE-7100 at a mass flux of 247 kg/m2 s. It outperformed most existing metallic flow boiling heat sinks using the same coolant at a similarly high coefficient of performance as small-size enhanced silicon microchannels. [ABSTRACT FROM AUTHOR]

Looks at gays in Cuba as portrayed in the motion picture `Fresa y Chocolate,' with reference to the Cuban reconciliation. Information on Jesus Diaz's 1985 melodrama `Lejania;' and `Vidas paralelas,' by Pastor Vega; Indepth look at `Fresa y Chocolate.'

Presents an overview of the achievement of Nobel Prize for Literature awardee Octavio Paz. Affinity with surrealists; Years in the United States and Europe, and a brief sojourn in the orient; Stature and influence as accounted by his `universalist poetics' and his being a `literary one-man band.'

Discusses the revised version of an essay `Cuba at the Crossroads: The Future of Democracy in Cuba,' called the `Unburnt Bridges' sponsored by James Dickey Center for International Understanding at Dartmouth College, Hanover, New Hampshire. Various parts of the essay dealing with the leaders of Cuba; Details of the same.