A Comprehensive study on Cartilage Tympanoplasty in Adhesive Otitis Media

INTRODUCTION: The management of the atelectatic ear continues to be one of the most controversial issues facing the otolaryngologist. Much of the confusion associated with this disorder stems from a poor understanding of the underlying pathophysiologic conditions that ultimately lead to changes in the tympanic membrane, resulting in atrophy, diffuse or local retractions, and cholesteatoma formation. Likewise, the lack of an accepted classification or grading scheme for the atelectatic ear has made it difficult to elucidate and predict the natural history of this disease and effectively predict those cases that will ultimately develop complications, such as cholesteatoma. The controversy is augmented by the fact that, early in the course of the disease, and even in the presence of incus erosion, hearing loss is frequently minimal and the patient, for the most part, asymptomatic. OBJECTIVE: The surgical management of adhesive otitis media is debatable. Adhesive otitis media progressing to cholesteatoma cannot be predicted, and hearing remains normal until later in the disease course. Hence surgery is done only when there is a hearing loss or frank cholesteatoma develops, where an extensive surgery may be needed. Earlier intervention is often avoided due to near normal hearing levels at this stage in some cases. Hearing results who have undergone cartilage tympanoplasty with or without ossicular reconstruction are reported for patients with adhesive otitis media. Study design: This is a prospective study. Setting: Study was done at Madras Medical College and Rajiv Gandhi Govt General Hospital, Chennai-3. Patients: A total of 30 patients (31 ears) aged 13-48 years underwent cartilage tympanoplasty with or without ossicular reconstruction. Interventions: Tympanotomy followed by cartilage reconstruction of the tympanic membrane, with ossicular reconstruction if there is any ossicular discontinuity. Main Outcome Measure(s): Post-operative pure tone average, air-bone gap for 3 frequencies (500, 1000, 2000 Hz) compared to pre-operative levels. RESULTS: There was a statistically significant improvement in hearing. CONCLUSIONS: Management of adhesive otitis media with cartilage perichondrium tympanoplasty with or without ossiculoplasty is a proven modality of treatment with successful results. Cartilage gives a tensile strength to the tympanic membrane which prevents further retractions inspite of the continuing Eustachian tube dysfunction and thus prevents cholesteatoma formation without compromising on hearing

A Review on Photo Voltaic MPPT Algorithms

A photovoltaic generator exhibits nonlinear voltage-current characteristics and its maximum power point varies with solar radiation and cell temperature. A Dc/Dc power converter is used to match the photovoltaic system to the load and to operate the PV (photo voltaic) cell array at maximum power point. Maximum Power Point Tracking (MPPT) is a process which tracks one maximum power point from PV array input, varying the ratio between the voltage and current delivered to get the most power it can. There are different techniques proposed with lot of algorithms are being used in the MPPT controller to extract the maximum power. It is very difficult for the photo voltaic designers, researchers and academic experts to select a particular MPPT technique for a particular application which requires the background knowledge and comparative features of various MPPT algorithms. This paper will be avaluable source for those who work in the photo voltaic generation, so its objective is to review the main MPPT algorithms in practice and analyzes the merits and demerits with various factors

Modeling and Performance Analysis of New Cuk Converter Topology for Photovoltaic Applications

Photovoltaic (PV) is a technical name in which radiant (photon) energy from the sun is converted to direct current (dc) Electrical Energy. PV power output is still low, continuous efforts are taken to develop the PV converter and controller for maximum power extracting efficiency and reduced cost factor. The maximum power point tracking (MPPT) is a process which tracks one maximum power point from array input, varying the ratio between the voltage and current delivered to get the most power it can. The selection of right converter for different application is a key factor for the optimum performance of the photo voltaic system. This paper details the study on state of the art in research works on Cuk power converters and their characteristics. A new cuk converter topology has also been proposed for the optimal performance of the photovoltaic system. Modeling of the PV array and simulation of basic cuk converter and the proposed cuk converter is carried out in Matlab/Simulink Software. Index Terms - PV Module, MPPT, Incremental Conductance (IC) Algorithm, Cuk converter, Optimal performanc

Simulation of III-V Material Based Steep Slope Tunnel FET for RF Harvester Application

Due to the limitation of Sub-threshold Swing (SS) of 60 mV/dec in CMOS, alternately Tunnel FETs (TFETs) are more attractive in recent years since it has high energy efficiency and better switching performance even at a reduced voltage level. Because it has the benefits of Band to Band Tunneling (BTBT) behavior of operating mechanism and achieved a steep slope characteristic of less than 60 mV/dec. Despite these merits due to the band to band tunneling, the conventional Silicon based TFET is suffered from very low and limited ON-state current due to indirect and large energy gap feature. In the indirect band gap, the conservation of momentum occurs only when the absorption and emission of a photon are required which makes the absorption coefficient lower and limits the flow of electron. To address this problem, in this paper, a Hetero-Junction Tunnel FET (HTFET) devices employing with different lower bandgap materials (InAs/GaSb and InGaAs/InP) are designed by using Silvaco TCAD device simulator. The overall DC and analog/RF performance of HTFET devices are being extracted and investigated suitable for RF energy harvesting applications. The InAs/GaSb HTFET has shown a superior in characteristics by achieving a higher ON-state current of 2.3 mA/μm at Vgs = 1V, OFF current leakage of 4.18 x 10-11 A/μm, SS of 22.18 mV/dec and cut-off frequency range from MHz to GHz in operation. Under very low ambient RF level or sub-milliwatt (< 0 dBm) level conditions, the conventional CMOS based rectifier in RF harvester shows very poor performance and probably fails to convert RF signal into DC output voltage. This is due to the SS limitation of 60 mV/dec. Hence, HTFET based RF harvester is proposed and implemented in the circuit level by using the Keysight ADS software. The result indicates that a two-stage Dickson voltage multiplier design using InAs/GaSb HTFET can able to produce a DC output of 1.9 V, 1.6 μA @ 0 to -10 dBm, maximum efficiency of 59 % @ -14 dBm, operating frequency of 850 MHz at 10 kΩ loads with a sensitivity of 0 to -25 dBm

Simulation of III-V Material Based Steep Slope Tunnel FET for RF Harvester Application

Due to the limitation of Sub-threshold Swing (SS) of 60 mV/dec in CMOS, alternately Tunnel FETs (TFETs) are more attractive in recent years since it has high energy efficiency and better switching performance even at a reduced voltage level. Because it has the benefits of Band to Band Tunneling (BTBT) behavior of operating mechanism and achieved a steep slope characteristic of less than 60 mV/dec. Despite these merits due to the band to band tunneling, the conventional Silicon based TFET is suffered from very low and limited ON-state current due to indirect and large energy gap feature. In the indirect band gap, the conservation of momentum occurs only when the absorption and emission of a photon are required which makes the absorption coefficient lower and limits the flow of electron. To address this problem, in this paper, a Hetero-Junction Tunnel FET (HTFET) devices employing with different lower bandgap materials (InAs/GaSb and InGaAs/InP) are designed by using Silvaco TCAD device simulator. The overall DC and analog/RF performance of HTFET devices are being extracted and investigated suitable for RF energy harvesting applications. The InAs/GaSb HTFET has shown a superior in characteristics by achieving a higher ON-state current of 2.3 mA/μm at Vgs = 1V, OFF current leakage of 4.18 x 10-11 A/μm, SS of 22.18 mV/dec and cut-off frequency range from MHz to GHz in operation. Under very low ambient RF level or sub-milliwatt (< 0 dBm) level conditions, the conventional CMOS based rectifier in RF harvester shows very poor performance and probably fails to convert RF signal into DC output voltage. This is due to the SS limitation of 60 mV/dec. Hence, HTFET based RF harvester is proposed and implemented in the circuit level by using the Keysight ADS software. The result indicates that a two-stage Dickson voltage multiplier design using InAs/GaSb HTFET can able to produce a DC output of 1.9 V, 1.6 μA @ 0 to -10 dBm, maximum efficiency of 59 % @ -14 dBm, operating frequency of 850 MHz at 10 kΩ loads with a sensitivity of 0 to -25 dBm

Simulation of III-V Material Based Steep Slope Tunnel FET for RF Harvester Application

Due to the limitation of Sub-threshold Swing (SS) of 60 mV/dec in CMOS, alternately Tunnel FETs (TFETs) are more attractive in recent years since it has high energy efficiency and better switching performance even at a reduced voltage level. Because it has the benefits of Band to Band Tunneling (BTBT) behavior of operating mechanism and achieved a steep slope characteristic of less than 60 mV/dec. Despite these merits due to the band to band tunneling, the conventional Silicon based TFET is suffered from very low and limited ON-state current due to indirect and large energy gap feature. In the indirect band gap, the conservation of momentum occurs only when the absorption and emission of a photon are required which makes the absorption coefficient lower and limits the flow of electron. To address this problem, in this paper, a Hetero-Junction Tunnel FET (HTFET) devices employing with different lower bandgap materials (InAs/GaSb and InGaAs/InP) are designed by using Silvaco TCAD device simulator. The overall DC and analog/RF performance of HTFET devices are being extracted and investigated suitable for RF energy harvesting applications. The InAs/GaSb HTFET has shown a superior in characteristics by achieving a higher ON-state current of 2.3 mA/μm at Vgs = 1V, OFF current leakage of 4.18 x 10-11 A/μm, SS of 22.18 mV/dec and cut-off frequency range from MHz to GHz in operation. Under very low ambient RF level or sub-milliwatt (< 0 dBm) level conditions, the conventional CMOS based rectifier in RF harvester shows very poor performance and probably fails to convert RF signal into DC output voltage. This is due to the SS limitation of 60 mV/dec. Hence, HTFET based RF harvester is proposed and implemented in the circuit level by using the Keysight ADS software. The result indicates that a two-stage Dickson voltage multiplier design using InAs/GaSb HTFET can able to produce a DC output of 1.9 V, 1.6 μA @ 0 to -10 dBm, maximum efficiency of 59 % @ -14 dBm, operating frequency of 850 MHz at 10 kΩ loads with a sensitivity of 0 to -25 dBm

Recent advances in the design and development of radio frequency-based energy harvester for powering wireless sensors: a review

Wireless sensor networks (WSNs) are spatially distributed sensor systems used to collect precise data from a large area of interest. WSN is usually deployed in the off-grid, and its widespread deployment is limited due to its requirement for the continuous and large amount of power. Energy harvesting has been recognized as a promising solution which has gained a lot of attention in recent years pertaining to enabling a self-sustainable operation of WSN. Radio Frequency (RF) is identified as an energy source that can be further used to harvest required energy for the WSN sensors. This paper outlines the motivation of RF energy harvesting for powering the WSN components. It is found that the rectenna circuit in RF harvester deals with very low amplitude of signals, and it requires further improvement in its feature and capabilities with reducing form factors. In this article, recent design and development consideration involved in rectenna circuit and corresponding performance trade-offs are being discussed. It also discusses the recent techniques involved in improving the overall power conversion efficiency of rectenna. The authors address the key challenging issues yet need to concentrate on further enhancements. This review will aid as a guide in the future, to develop an energy-efficient and high-performance RF harvester circuit, which needs to be taken to the next advance level

A novel dual electrode and gate engineered doping-less TFET for performance enhancement

Tunnel FET (TFET) is a promising device for ultra-low power applications because it has the benefits of band to band tunneling (BTBT) behavior of operating mechanism and achieving the sub-threshold swing (SS) value of less than 60mV/dec. However, it suffers from low ON state current and ambipolar in nature. In addition, it also has poor analog/RF performances. To address these problems, a novel dual electrode and a double metal gate Doping-less TFET (DEDMGDLTFET) is proposed in this work by using charge plasma technique. To improve the BTBT rate and ON-state current, a tunneling gate length (Ltg) of proper work function is created at the source-channel junction. The distance between the source and gate electrode (Lgs) is kept at a minimum of 2 nm significantly, to reduce the ambipolar behavior. To enhance the analog/RF performance, a dual electrode structure is proposed on both sides of source and drain regions to induce the carriers uniformly. By using Silvaco TCAD simulator, different n-type DLTFET structures are designed and compared. The overall DC and analog/RF performance of all the DLTFETs are investigated. The proposed DEDMGDLTFET achieved a higher ON current of5.26 x 10-7 A/µm at Vgs and Vds =0.5 V, SS of 30.27 mV/dec, Cut-off frequency range from MHZ to GHz and suppress the ambipolar order of 1010 effectively

An enhanced sensitivity RF energy harvester system using tunnel FET based rectifier

Radio Frequency (RF) energy harvesting system is a viable solution for powering ultra-low power sensors as long as there is minimal am-bient power that exists around it. However, at very low ambient RF level or under sub-milliwatt (< -20 dBm) level conditions, the RF recti-fier in the harvester system shows very poor performance and probably fails to convert RF signal into DC output voltage. This is due to the sub-threshold voltage limits or weak sensitivity of the rectifying device used in the rectifier. However, to actively operate it in sub-milliwatt level RF input, this research proposes a band-to-band tunneling behavior of Tunnel FET (TFET) device. The steep slope characteristic of TFET contributes in improving the sensitivity, output voltage, and power conversion efficiency (PCE). Keysight Advanced Design System (ADS) software is used to conduct a simulation study on our proposed idea. An LC matching network is also designed using the smith chart tool to achieve maximum sensitivity. The proposed concept achieved a maximum sensitivity of -60 dBm at UHF of 900 MHz and produced an output voltage of 350 mV at -25 dBm. A maximum PCE of 70% at -39 dBm is obtained in the 3 stage voltage multiplier