Trends in Cardiac Pacemaker Batteries

Batteries used in Implantable cardiac pacemakers-present unique challenges to their developers and manufacturers in terms of high levels of safety and reliability. In addition, the batteries must have longevity to avoid frequent replacements. Technological advances in leads/electrodes have reduced energy requirements by two orders of magnitude. Micro-electronics advances sharply reduce internal current drain concurrently decreasing size and increasing functionality, reliability, and longevity. It is reported that about 600,000 pacemakers are implanted each year worldwide and the total number of people with various types of implanted pacemaker has already crossed 3 million. A cardiac pacemaker uses half of its battery power for cardiac stimulation and the other half for housekeeping tasks such as monitoring and data logging. The first implanted cardiac pacemaker used nickel-cadmium rechargeable battery, later on zinc-mercury battery was developed and used which lasted for over 2 years. Lithium iodine battery invented and used by Wilson Greatbatch and his team in 1972 made the real impact to implantable cardiac pacemakers. This battery lasts for about 10 years and even today is the power source for many manufacturers of cardiac pacemakers. This paper briefly reviews various developments of battery technologies since the inception of cardiac pacemaker and presents the alternative to lithium iodine battery for the near future

Acceleration Profiles and Processing Methods for Parabolic Flight

Parabolic flights provide cost-effective, time-limited access to "weightless" or reduced gravity conditions experienced in space or on planetary surfaces, e.g. the Moon or Mars. These flights facilitate fundamental research - from materials science to space biology - and testing/validation activities that support and complement infrequent and costly access to space. While parabolic flights have been conducted for decades, reference acceleration profiles and processing methods are not widely available - yet are critical for assessing the results of these activities. Here we present a method for collecting, analyzing, and classifying the altered gravity environments experienced during a parabolic flight. We validated this method using a commercially available accelerometer during a Boeing 727-200F flight with $20$ parabolas. All data and analysis code are freely available. Our solution can be easily integrated with a variety of experimental designs, does not depend upon accelerometer orientation, and allows for unsupervised and repeatable classification of all phases of flight, providing a consistent and open-source approach to quantifying gravito-intertial accelerations (GIA), or $g$ levels. As academic, governmental, and commercial use of space increases, data availability and validated processing methods will enable better planning, execution, and analysis of parabolic flight experiments, and thus, facilitate future space activities.Comment: Correspondence to C.E. Carr ([email protected]). 15 pages, 4 figures, 3 supplemental figures. Code: https://github.com/CarrCE/zerog, Dataset: https://osf.io/nk2w4

Invention into the AC Voltage Regulator with V/F Technique for Induction Motor Starting Applications

Modern electrical motors are available in many different forms with different mounting arrangements. To ensure a long life for the motor it is important to select it with correct degree of protection when operating under heavy duty conditions in a severe environment. Smooth starting is also one of major considerations to get long life and optimum efficiency. The conventional method to start an asynchronous motor with a soft starter is by reducing the voltage of the motor by varying the voltage “off time”. The “off time” could for example be controlled to achieve a desired maximum current level or a constant driving torque.  Even if the voltage is reduced the fundamental frequency of the voltage is equal to the supply voltage frequency. That gives a large difference between angular speed of supply voltage and angular speed of the rotor during start. Due to the large difference in angular speed the motor flux will be low and thereby also the ability to produce torque. Instead of using the conventional control method with a reduced voltage it is possible to use a method with controlled flux similar to frequency inverters for soft-starters. As the soft-starter does not have the intermediate DC energy storage the applied voltage vector has to be directly modulated from the mains supply

EVALUATION OF THE EFFECT OF ELEVATED CO2 ON BIOEFFICACY OF BUPROFEZIN INSECTICIDE AGAINST BROWN PLANT HOPPER, Nilaparvata lugens (STÅL)

The effect of elevated CO2 (570±25ppm) on the brown plant hopper (BPH) population, rice yield parameters, and efficacy of buprofezin (0.05%) in terms of spray volume was studied in an open top chamber (OTCs) during rainy season 2017 and 2018. The pest population was observed to be higher during 2017 compared to the rainy season of 2018. Under elevated CO2, rice plants had more vegetative tillers (18%) and reproductive tillers (22.1%), but there was a decrease in 1000-seed weight (11.2%), seed number per panicle (3.91%), and grain yield (18.8%) in comparison to ambient CO2 grown rice plants. The spray volumes of 700, 600, 500, and 400 l/ha each caused higher BPH mortality under ambient CO2 compared to elevated CO2. A spray volume of 500 l/ha did not prove as effective under elevated CO2 as under ambient CO2. Lower efficacy of spray volume of 500 l/ha under elevated CO2 could be ascribed to higher canopy size under elevated CO2 due to higher tillering. Increased crop canopy size under elevated CO2 may thus require higher spray volume to ensure proper coverage. Results of the study suggested a need to revise spray volume recommendations to facilitate effective management of BPH under climate change