Simple Technical Implementation Research Articles

Microplegia in paediatric hearts.

A basic prerequisite for a good surgical outcome in heart surgery is optimal myocardial protection. However, cardioplegia strategies used in adult cardiac surgery are not directly transferable to infant hearts. Paediatric microplegia, analogous to Calafiore cardioplegia used in adult cardiac surgery, offers the advantage of safe myocardial protection without haemodilution. The use of concentration-dependent paediatric microplegia is new in clinical implementation. Paediatric microplegia has been in clinical use in our institution since late 2014. It is applied via an 1/8 inch tube of a S5-HLM roller pump (LivaNova, Italy). As cardioplegic additive, a mixture of potassium (K) 20mL (2mmol/mL potassium chloride 14.9% Braun) and magnesium (Mg) 10mL (4mmol/mL Mg-sulphate Verla® i. v. 50%) is fixed into a syringe-pump (B. Braun, Germany). This additive is mixed with arterial patient blood from the oxygenator in different flowdependent ratios to form an effective cardioplegia. After microplegia application of initially 25mmol/L K with 11mmol/L Mg for 2min, a safe cardioplegic cardiac arrest is achieved, which after release of the coronary circulation, immediately returns to a spontaneous cardiac-rhythm. In the case of prolonged aortic clamping, microplegia is repeated every 20min with a reduction of the application dose of K by 20% and Mg by 30% (20mmol/L K; 8.5mmol/L Mg) and a further reduction down to a maintenance dose (15mmol/L K; 6mmol/L Mg) after additional 20min. The microplegia adapted to the needs of paediatric myocardium is convincing due to its simple technical implementation for the perfusionist while avoiding haemodilution. However, the required intraoperative interval of microplegia of approx. 20min demands adapted intraoperative management from the surgeon.

Multispectral LIF-Based Standoff Detection System for the Classification of CBE Hazards by Spectral and Temporal Features.

Laser-induced fluorescence (LIF) is a well-established technique for monitoring chemical processes and for the standoff detection of biological substances because of its simple technical implementation and high sensitivity. Frequently, standoff LIF spectra from large molecules and bio-agents are only slightly structured and a gain of deeper information, such as classification, let alone identification, might become challenging. Improving the LIF technology by recording spectral and additionally time-resolved fluorescence emission, a significant gain of information can be achieved. This work presents results from a LIF based detection system and an analysis of the influence of time-resolved data on the classification accuracy. A multi-wavelength sub-nanosecond laser source is used to acquire spectral and time-resolved data from a standoff distance of 3.5 m. The data set contains data from seven different bacterial species and six types of oil. Classification is performed with a decision tree algorithm separately for spectral data, time-resolved data and the combination of both. The first findings show a valuable contribution of time-resolved fluorescence data to the classification of the investigated chemical and biological agents to their species level. Temporal and spectral data have been proven as partly complementary. The classification accuracy is increased from 86% for spectral data only to more than 92%.

Reduction of Nonuniformity in the Thickness of a Galvanic Coating Using Disableable Anode Sections under Current Reversal Conditions

A method of reducing the nonuniformity of a galvanic coating on the basis of disableable anode sections in the inverse current reversal regime was proposed in a relatively simple technical implementation, thus providing the possibility to broaden the variety of articles treated for mass production. The galvanic process in the inverse current reversal regime with disableable anode sections was formalized by the formulation of an optimal control problem and the development of a mathematical model. Some results of computer-aided modeling were presented alongside with the results of verifying the developed mathematical model for adequacy with the use of experimental data to demonstrate the efficiency of the method proposed.

Прецизійна система термостабілізації підвищеної потужності

An analysis of principles construction of temperature stabilization and an experimental research on temperature stabilization system have been carried out. The features of design and construction of systems for automatic temperature control have been considered. A realization of highly efficient temperature controller is proposed. The principles of construction of temperature stabilization systems using Peltier thermoelectric modules are investigated. A highly effective thermal stabilization system for Peltier modules with output power >50 W without the use of expensive controllers has been developed. It is shown that the created thermostabilization system ensures stability of temperature maintenance 0,01 °С. The highly effective system of thermal stabilization optimally combines the basic specifications: high temperature stability, high energy efficiency, low current ripple TEM and low cost. The urgency of the development is due to the fact that the known temperature controllers, which provide high accuracy of the maintenance of the set temperature level in the established modes and good quality of transient processes, have a complicated technical implementation with the use of either programmable controllers or computer control. Their disadvantage is a high cost and low accuracy of temperature stabilization in the range of 0,01–0,1 С. Regulators with a simple technical implementation and low price support the accuracy of stabilizing the temperature of 0,1 С in the established modes with significant error and do not provide stability of the stabilization system in conditions of change in wide limits of the temperature of the surrounding environment. The highly stable temperature regulator proposed in the article with a relatively simple technical implementation solves this contradiction. The controller uses a one-circuit automatic temperature control system. The control loop contains a proportional-integral-differential (PID) regulator, which, in conditions of disturbing effects on the stability of maintaining the desired temperature of the object, provides the necessary change in the control signal at the input of the control circuit.

On the Tradeoff between Performance and Programmability for Software Defined WiFi Networks

WiFi has become one of the major network access networks due to its simple technical implementation and high‐bandwidth provisioning. In this paper, we studied software defined WiFi networks (SDWN) against traditional WiFi networks to understand the potential benefits, such as the ability of SDWN to effectively hide the handover delay between access points (AP) of the adoption of the SDWN architecture on WiFi networks and identify representative application scenarios where such SDWN approach could bring additional benefits. This study delineated the performance bottlenecks such as the throughput degradation by around 50% compared with the conventional WiFi networks. In addition, our study also shed some insights into performance optimization issues. All of the performance measurements were conducted on a network testbed consisting of a single basic service set (BSS) and an extended service set (ESS) managed by a single SDN controller deployed with various laboratory settings. Our evaluation included the throughput performance under different traffic loads with different number of nodes and packet sizes for both TCP and UDP traffic flows. Handover delays were measured during the roaming phase between different APs against the traditional WiFi networks. Our results have demonstrated the tradeoff between performance and programmability of software defined APs.

All-optical helicity dependent magnetic switching in Tb-Fe thin films with a MHz laser oscillator.

We demonstrate all-optical magnetic switching (AOS) in an amorphous Tb30Fe70 thin film, triggered by a 5.1 MHz laser oscillator. The magnetic layer is grown on SiO2/Si substrate. An identical magnetic film deposited on a microscope glass slide reveals no AOS but solely thermally induced demagnetization. This effect is due to heat accumulation by multiple laser pulses because of the low thermal conductivity of the glass substrate. In contrast, the use of a proper heat sink (e.g. SiO2/Si) avoids the need for low repetitive laser amplifier systems to induce AOS and paves the way for a cheap and simple technical implementation using conventional laser oscillators.

Precision programmed scanning of a planet surface by a nonrigid orbital telescope

This paper continues the study [1] of the problem of formation of program controls for a nonrigid orbital telescope with gyrodynes as actuators. In [1] the problem of program control for guidance of a nonrigid telescope to a given region was considered. In this paper, we solve the problem of calculation of control for the regime of programmed scanning of the studied domain on an underlying surface of a planet. Here, similar to [1], the direct method is used for control calculation. Along with the guarantee of problem-free feasibility of "direct" program controls for actuating force gyroscopes, the direct method makes it possible to obtain the control law with required quality, for example, time-linear control by exact calculation (without subsequent approximations), which provides it simple technical implementation; in this case gyro-units of gyrodynes are rotated with piecewise constant acceleration (for inertia-free gyrodyne model the gyro-unit rotation velocities represent control laws) [2]. If a set of inertial flywheels is used as an actuating set, the direct method of calculation makes it possible to automatically distribute control action over separate actuating elements.