Circuit In Conjunction Research Articles

Paediatric ECMO: Alternative Anticoagulation Strategies for ECMO Purposes

Extracorporeal membrane oxygenation (ECMO) circuits have undergone numerous modifications pertinent to their clinical environment and tasks over time; however, identical anticoagulation strategies have remained. Unfractionated heparin (UFH) is the default anticoagulant for ECMO. Detected in 1916 and made available as a purified substance for human application in the 1930s, UFH is one of the oldest drugs still in use. To reduce the morbidity associated with circuit clotting and subsequent patient coagulopathy, the current institution has routinely been using nitric oxide (NO), which can be safely delivered through the sweep gas to the oxygenator of an ECMO circuit in conjunction with prostacyclin. By preventing platelet adhesion to artificial surfaces, mitigating the systemic inflammatory response and protection against ischaemia–reperfusion injury it may improve oxygen delivery to hypoxic tissue. Bivalirudin, a direct thrombin inhibitor, has also been used to remove or significantly reduce the use of UFH.

Compact, flexible and highly selective wideband complementary FSS with high angular stability

AbstractThis article presents a novel miniaturized (0.105λ0 × 0.105λ0) flexible complementary frequency selective surfaces (CFSS) structure with sharp band edge selectivity and very high angular stability. To explore two diverse applications as a passband and stopband filter, a novel complementary convoluted square loop (CCSL) type structure has been designed and investigated on ultrathin dielectric material of thickness 0.0023λ0. The second-order wide controllable passband with fractional bandwidth of 19.23% (−3 dB) and remarkably wide stopband of 64.7% (−10 dB) and 54.8% (−20 dB) respectively have been achieved by using a cascaded resonating structure which is composed of asymmetrical meandered CCSL array, arranged on two ultrathin dielectric layers with air foam separation. This particular format would lead to sharp band edge selectivity with steep roll-off (72.43 dB/GHz) and an excellent passband selectivity factor (0.731). An equivalent lumped LC circuit in conjunction with the transmission line model has also been adopted to comprehend the physical mechanism of the proposed single layer and double layer structures. Further, better passband and stopband angular stability at an oblique incident angle of 45° and the bending characteristics have also been investigated thoroughly for the proposed flexible CFSS to check their employability in different conformal structures with WiMAX passband and WLAN stopband application.

Treatment of hyperammonemia using in-line renal replacement and hyperosmolar therapies within an extracorporeal membrane oxygenation circuit.

After orthotopic lung transplantation, hyperammonemia can be a rare complication secondary to infection by organisms that produce urease or inhibit the urea cycle. This can cause neurotoxicity, cerebral edema, and seizures. Ammonia is unique in that it has a large volume of distribution. However, it is also readily dialyzable given its small molecular weight. As such, removal of ammonia requires renal replacement modalities that can both rapidly remove ammonia from the plasma space and allow for continuous removal to prevent rebound accumulation from intracellular stores. Prevention of iatrogenic osmotic lowering in this setting is required to prevent worsening of cerebral edema. Herein, we describe use of sequential in-line renal replacement therapy using both intermittent hemodialysis and continuous venovenous hemofiltration within an extracorporeal membrane oxygenation circuit in conjunction with higher sodium dialysate and 7.5% hypertonic saline to achieve these treatment goals.

A Fuzzy-Based Chat-bot Messenger for Home Intelligent System with Multiple Sensors

The integration of chatbot engines and home automation systems is an area that is seeing a lot of development and resources dedicated to in recent years. Many devices nowadays are constantly connected to the Internet (IoT) and this is a huge opportunity to create a software application that can manage an area of our everyday life. This paper was aimed at the design and implementation of a low-cost fuzzy-based system which converts fuzzy values to Crips values that uses weather conditions of a particular environment to function as an intelligent system in a smart home. The functions of this system is made possible with the integration of multiple sensors of Pewatron zirconia in a circuit in conjunction with fuzzy values in a chatbot messenger environment with the aid of the Telegram Bot service to control the state of electrical devices in the house based on atmospheric weather conditions. The commands to the control of electrical appliances was done by creating user interface that interfaces with the mobile devices that provides intelligent response programmed on to the Freescale S32K microcontroller with wireless fidelity. The main focus was to create a chat interface that allows the users to interact with their systems at home in their convenience(reaching the users where they already are, like Telegram, Facebook etc.), creating a system that not only allows you to control and manage your home electrical systems but also a networking system that gives you leverage of ease and faster network in terms of operation in controlling your home devices through decisions. The outcome of this fuzzy-based smart home intelligent system proved reliable and efficient more than the previously designed smart home systems based on relay and microcontroller. More so, the system reduces powe

Low-power latch comparator with accurate hysteresis control

Abstract Recent research has focused on finding ways to control hysteresis of dynamic comparators. The current proposed techniques are based on either geometrical dimension adjustment or digital control. The first case does not allow for post fabrication control, while the second has limited accuracy. This paper presents a new dynamic comparator design with external hysteresis adjustment using an analog voltage. This is achieved by proposing an architecture including control devices with a specific sizing. This is performed with no significant increase of the design complexity, keeping the power consumption as low as possible. The design is analyzed, showing that the proposed solution allows accurate hysteresis adjustment without affecting the inherent circuit properties. The dynamic comparator is also implemented using a 180 nm commercially available CMOS technology. The results show that a variation of 550 mV of the control voltage allows an accurate hysteresis adjustment ranging from 0 to 40 mV, according to the input conditions. Moreover, the simplicity of the circuit in conjunction with the use of dynamic technology have allowed the best performances to be achieved compared to the current state of the art, in terms of energy with an FoM equal to 116 fJ/decision and silicon area of 180 µm2 .

High-Efficient Broadband CPW RF Rectifier for Wireless Energy Harvesting

In this paper, the implementation of a compact, wideband, single layer, and simple RF rectifier design is discussed. The proposed rectifier configuration is based on the coplanar waveguide transmission line. The rectifier is constructed using the voltage doubler circuit in conjunction with a broadband matching network. To obtain a small circuit size, the matching circuit is constituted with a series dual-inductive lumped element. The overall rectifier dimensions are very compact $22.5\times 31\,\,\text {mm}^{2}$ . In order to accurately characterize the rectifier performance, the electromagnetic and harmonic balance simulations are conducted using the Agilent, ADS software. The comparison shows good agreement between the simulation and measurement results. For instance, the peak measured efficiency is 74.8% at 10-dBm RF input power and the corresponding simulated value is 75% with a terminal load of 1 $\text{k}\Omega $ . The efficient frequency range is extending from 0.1 to 2.5 GHz, with an efficiency of more than 45% at input power 10 dBm.

Hardware trojans in 3-D ICs due to NBTI effects and countermeasure

Going vertical as in 3-D IC design, reduces the distance between vertical active silicon dies, allowing more dies to be placed closer to each other. However, putting 2-D IC into three-dimensional structure leads to thermal accumulation due to closer proximity of active silicon layers. Also the top die experiences a longer heat dissipation path. All these contribute to higher and non-uniform temperature variations in 3-D IC; higher temperature exacerbates negative bias temperature instability (NBTI). NBTI degrades CMOS transistor parameters such as delay, drain current and threshold voltage. While the impact of transistor aging is well understood from the device point of view, very little is known about its impact on security. We demonstrated that a hardware intruder could leverage this phenomenon to trigger the payload, without requiring a separate triggering circuit. In this paper we provide a detailed analysis on how tiers of 3-D ICs can be subject to exacerbated NBTI. We proposed to embed threshold voltage extractor circuit in conjunction with a novel NBTI-mitigation scheme as a countermeasure against such anticipated Trojans. We validated through post-layout and Monty Carlo simulations using 45nm technology that our proposed solution against NBTI effects can compensate the NBTI-effects in the 3-D ICs. With the area overhead of 7% implemented in Mod-3 counter, our proposed solution can completely tolerate NBTI-induced degraded threshold voltage shift of up to 60%.

Toward a New PHY Layer Scheme for Decoding Tags Collision Signal in UHF RFID System

Tag collision is one of the most significant limitations of the RFID systems. Current anti-collision algorithms process the problem in medium access control layer as an estimation of the collided tags number. This process requires retransmission of the RN16 sequence, and hence the discarding of signals in the PHY layer. This letter shows how to use the physical signal in order to decode collided tags. The contributions of this letter are as follows: 1) a simulation model of the Ultra High Frequency RFID system using a Nexxim circuit in conjunction with a system designer using Ansoft Designer simulator platform; 2) a proposed edge transition scheme to recover collision and decode tag signals. This scheme permits us to decode collision signal of three tags, which increases the system throughput from 0.37 (slotted Aloha) to 1.37; 3) an experimental setup that was able to collect and decode the real collision tag signal thanks to our proposed edge transition scheme.

Influence of low external magnetic field on electric field induced strain behavior of 9/70/30, 9/65/35 and 9/60/40 PLZT ceramics

In this work, Pb0.91La0.09(ZrxTi1−x)0.9775O3 PLZT ceramics, where x =0.70, 0.65 and 0.60, were prepared by a solid-state mixed-oxide technique. Structural information was investigated by X-ray diffraction method. Electric field induced polarization and strain behavior of the PLZT ceramics under an influence of static magnetic field were measured by a Sawyer-Tower circuit in conjunction with Michelson interferometer at various static magnetic fields (0–30.7mT). The results showed that the imposed magnetic field affected the polarization and induced strain behaviors in PLZT ceramics More interestingly, the imposed magnetic field showed more significant influence on the PLZT ceramic composition near morphotropic phase boundary (MPB), i.e. PLZT 9/65/35. The spontaneous polarization of 180° domain switching was seen to be suppressed by the applied magnetic field.

Improvement of Power Quality by Realising Renewable Energy based Cascaded Five Level Control Power Conditioner

Renewable Energy Sources(RES) are best alternative to conventional energy source. This paper presents a Renewable energy based Shunt Active Filter circuit in conjunction with Proportional Integral (PI) and Fuzzy Logic Controller (FLC) for the power-quality improvement. In today's world the loads are highly become electronic based which produce more harmonics and EMI. The main aim of this research work is to reduce current harmonics and reactive power compensation due to the non-linear loads. This paper studies an investigation of Cascaded Five-Level Inverter (CFLI) based SAF in PS. By using CFLI the harmonics distortion can be minimized and switching losses can also be minimized as it uses minimum number of switches. Sub-Harmonics Pulse Width Modulation (SHPWM) technique with Proportional and Integral (PI) controller and D-Q reference frame theory are proposed in this paper for reactive power compensation, reducing harmonic distortion and maintaining DC capacitor voltage. The Sub-Harmonic Pulse width modulation is used for switching the switches of CFLI. The reference compensating currents for SAF are calculated by using D-Q reference frame theory and PI controller is used for capacitors dc voltage regulation for SAF. The controls are made by controlling the RES voltage level for the whole system. The results are validated through MATLAB/Simulink simulation software and TMS320F2407 DSP with SAF and without SAF.

Experimental study of an energy efficient hybrid system for surface drying

Rapid surface drying is an important and energy intensive process in food and beverage packaging industry. Usually these products are dried at low dew-point temperatures (DPT) −10 to −20 °C and low dry ball temperatures (DBT) 20–30 °C for product quality optimization. The conveyor moves at very high speeds and it is necessary to expose as much of the drying surface to the drying effect in a shortest time possible. Re-condensation is a big problem in these systems and a good drying system is that preserves the quality of the product and is energy efficient. This paper presents a feasibility study to obtain the design parameters of a hybrid dryer suited for rapid drying applications. Drying process of a re-circulation heat pump is integrated with rotary dehumidifier (desiccant wheel) system. The system employed a refrigerant circuit in conjunction with a heat reactivated desiccant wheel to provide efficient drying capability and supply low DPT conditions. To increase the economic practicality of such a hybrid system, the combined system utilises the heat dissipated by the condenser in regenerating the desiccant wheel. The study shows that the proposed hybrid system can deliver supply air at much lower DPT compared to the single refrigerant circuit and a desiccant wheel. By operating the combined system in tandem, greater amount of dehumidification could be realised due to the improved ratio of latent to total load at the hybrid. Up to 60% heat energy can be saved in rapid surface drying applications by using the proposed hybrid system.

High Precision Image Centroid Computation via an Adaptive K-Winner-Take-all Circuit in Conjunction with a Dynamic Element Matching Algorithm for Star Tracking Applications

An approach for implementing a high precision image target centroid—center of mass (COM) detection system via an adaptive K-winner-take-all (WTA) circuit in conjunction with a 2-D dynamic element matching (DEM) algorithm implementation for image sensor arrays is proposed. The proposed system outputs a high precision COM location of the most salient target in a programmable active region of the field of view (FOV) for star tracking purposes and is suitable for real time applications. The system allows target selection and locking with multiple targets tracking capability. This solution utilizes the separability property of the COM, and therefore reduces the computational complexity by utilizing 1-D circuits for the computation. The DEM algorithm, commonly used in ADC and DAC circuits, allows reducing the required WTA circuit precision to 5–6 bits, while still achieving a high output precision. Simulation results prove the concept and demonstrate the high precision COM result. In addition, a possible low-level hardware implementation is described.

An undergraduate laboratory experiment on quantized conductance in nanocontacts

We describe an undergraduate laboratory experiment on conductance steps observed to occur near integer multiples of 2e2/h as nanocontacts form and break between gold wires in loose contact. This experimental arrangement was first described by Costa-Krämer et al. [Surf. Sci. 342, L1144 (1995)]. A simple op-amp circuit in conjunction with an inexpensive storage oscilloscope suffice to observe the steps. The experiment may be extended by interfacing to a computer, which accumulates a histogram of conductance values as the wires are brought into and out of contact many times. The histogram shows peaks near integer multiples of 2e2/h. We emphasize the pedagogical issues involved in bringing an experiment from forefront condensed-matter physics research into the undergraduate laboratory.

Taking dentistry to the top of the world on a Himalayan trek.

In October 1996 the author, a dental officer, was part of a group of ten people serving in the Royal Navy who walked the Annapurna circuit in conjunction with Five Valleys Travel and Trek Aid. The Annapurna circuit is situated in the north of Nepal bordering the Kingdom of Mustang and the Peoples Republic of China. It is a grueling 20 day trek reaching the dizzy heights of 18,000 feet, passing through some of the most beautiful and immense scenery in the world. The following is a short account of his experiences.

Novel three-phase SMR converter with inherent snubber energy recovery capability

This paper describes the switch mode rectifier (SMR) having a quite new circuit configuration, which has been developed by the authors and given the name "DC clamped type SMR" (DCC-SMR). The DCC-SMR is unique in that no bilateral switching device is used in the frequency conversion circuit. Therefore, the authors have used a DC snubber circuit in conjunction with the switching device of the DCC-SMR. This DC snubber circuit features a very simple structure consisting only of a capacitor with no need for a discharge resistance or for a complicated regenerative circuit for snubber energy. This is because snubber energy is regenerated on the primary side of the high frequency (HF) transformer by the main switch. Furthermore, an innovative method has been applied for magnetic saturation-preventive control of the HF transformer. The authors carried out operational checks on the main circuit and the snubber circuit of the DCC-SMR as well as on the magnetic saturation-preventive control circuit, and through experiments confirmed a satisfactory result. We manufactured an industrial DC power supply prototype of the DCC-SMR system having a DC output of 100 kW (100 V, 1000 A), with which input/output conversion efficiency 91.6%, input power factor 0.99 and input current total harmonic distortion factor 4.6% were obtained.

Method for measuring the stochastic properties of corona and partial-discharge pulses

A new method is described for measuring the stochastic behavior of corona and partial-discharge pulses which utilizes a pulse selection and sorting circuit in conjunction with a computer-controlled multichannel analyzer to directly measure various conditional and unconditional pulse-height and pulse-time-separation distributions. From these measured distributions it is possible to determine the degree of correlation between successive discharge pulses. Examples are given of results obtained from measurements on negative, point-to-plane (Trichel-type) corona pulses in a N2/O2 gas mixture which clearly demonstrate that the phenomenon is inherently stochastic in the sense that development of a discharge pulse is significantly affected by the amplitude of and time separation from the preceding pulse. It is found, for example, that corona discharge pulse amplitude and time separation from an earlier pulse are not independent random variables. Discussions are given about the limitations of the method, sources of error, and data analysis procedures required to determine self-consistency of the various measured distributions.

Normocapnic anaesthesia for intraocular surgery.

Measurement of intraocular pressure (IOP) by applanation tonometry in 23 patients undergoing lens extraction showed that a normocapnic general anaesthetic technique with controlled ventilation of the lungs (IPPV) reliably reduced the IOP by 50% for the duration of the operative period. This was not associated with large falls in systemic arterial pressure which are often a feature of spontaneously breathing halothane anaesthesia for eye surgery. Normocapnia and IPPV were easy to achieve by use of the single-limb coaxial Bain anaesthetic breathing circuit in conjunction with an electrically driven, small, and inexpensive ventilator while the anesthetic mixture of 33% oxygen and 0.5% halothane in nitrous oxide was delivered at a rate of 70 ml/kg body weight per minute.

On the use of active coupling networks with electrically small receiving antennas

An analysis of the noise performance of an active receiving antenna system consisting of an antenna, active coupling network, and high-gain preamplifier is described. It is shown how this noise performance can be described by circular loci in the output-impedance plane of the coupling network. These loci are not restricted to the right-half plane. A coupling network having an output impedance in the left-half plane was built using a negative-impedance converter (NIC), and experimental results obtained by using this circuit in conjunction with a short monopole are presented.

Electrically small complementary pair (ESCP) with interelement coupling

Electrically small (reduced size) antennas are inherently narrow-band or inefficient, or both. A summary is presented of prior work on complementary pair antennas and the use of the coupling between the two elements to optimize the impedance match and efficiency of such structures. The design of electrically small complementary pairs is described, and preliminary measurement results are shown for monopoles. These measurements indicate a substantial improvement in gain-bandwidth product as compared to conventional matching techniques for electrically small antennas. The power delivered to the external region is analyzed for both an individual monopole, and a pair of monopoles, by establishing the scattering matrices for both cases. The potential gain is calculated for the pair over the individual monopole, and it is shown that the pair can deliver up to twice the power to the exterior region if the mutual impedance term is optimized. In addition, the complementarization circuit in conjunction with the hybrid feed can reduce the effects of mutual impedances in steerable-beam arrays. Various special cases are discussed, varying from full complementarity to zero complementarity, and general conclusions are presented on the optimization of gain-bandwidth product. Applications include small individual antennas and scatterers as well as linear, planar, or circular arrays in a variety of fixed-station or vehicular uses.

Serial solution of heat-exchanger equations without a hybrid computer

A version of the serial-solution method is proposed which enables the equations of a counterflow heat exchanger to be solved without iteration, and with essentially central difference accuracy. The method is sufficiently simple for it to be implemented using an analogue circuit in conjunction with an inexpensive purpose-built hardware system. This hardware system performs some functions normally associated with a hybrid computer, and is described briefly. Specimen results are presented.