Study of correlation between perinatal outcome, placental coefficient and feto-placental ratio

Background: Pregnancy and birth are nature’s finest marvel wherein perfect symbiosis between the two individuals protects the little and weak one and also allows the propagation of genetic prototype of the other individual generation after generation. Placenta acts as a mirror which reflects intrauterine status of fetus. Placenta has an undisputed role in foetal development but still is grossly neglected organ which is equal to liver, lung and kidney in function.Methods: Placentae collected from labor rooms and operation theatres were studied for various parameters like weight, surface area, volume, area of calcification and infarction, number of cotyledons etc. Birth weight of babies was also noted, feto-placental weight ratio and placental coefficient was calculated.  Results: Average placental weight being 490.5 gm (range 295-660 gm). Placenta of male baby was found to be slightly heavier as compared to female babies. Birth weight of male babies was also more than female babies. Average placental surface area was found to be 225.5 sq. cm. Mean placental volume was recorded as 450.5 cu. cm. Foeto-placental weight ratio was found to be 5.41:1 irrespective of sex of the baby, 5.61:1 in case of male baby and 5.40:1 for female babies.Conclusion: The placenta is a mirror which reflects intrauterine status of the fetus.

Simulation studies for multichannel active vibration control

Traditional approach to vibration control uses passive techniques, which are relatively large, costly and ineffective at low frequencies. Active Vibration Control (AVC) is used to overcome these problems and in AVC additional sources (secondary) are used to cancel vibration from primary source based on the principle of superposition theorem Since the characteristics of the vibration source and environment are time varying, the AVC system must be adaptive. Adaptive systems have the ability to track time varying disturbances and provide optimal control over a much broader range of conditions than conventional fixed control systems. In multi channel AVC vibration fields in large dimensions are controlled and is more complicated. Therefore to actively control low frequency vibrations on large structures, multi channel AVC requires a control system that uses multiple secondary sources to control the vibration field simultaneously at multiple error sensor locations. The error criterion that can be directly measured is the sum of squares of outputs of number of sensors. The adaptive algorithm is designed to minimize this and the algorithm implemented is the quot;Multiple error LMS algorithmquot;. The best known applications of multiple channel FXLMS algorithm is in real time AVC and system identification. Additionalr applications are in the control of propeller induced noise in flight cabin interiors. In the present paper the results of simulation studies carried out in MATLAB as well as on TMS320C32 DSP processor will be brought out for a two-channel case

Compact field programmable gate array (FPGA) controller for Aircraft / Aerospace structures

The reduction of vibration in Aircraft/Aerospace structures as well as helicopter fuselage is becoming increasingly important. The active control techniques [1] using adaptive digital filters [2] are very much suitable amp; well proven. Hitherto this was being achieved using high speed Digital Signal Processors (DSPs). But the throughput requirements of these systems have strained the abilities of general purpose DSPs. The Field Programmable Gate Arrays (FPGAs) have emerged as an alternative to standard DSPs, since they13; incorporate arrays of dedicated multipliers, embedded memory amp; high speed I/O. The silicon resources of an13; FPGA lead to staggering performance gains x2013; while the fastest general purpose DSP can deliver up to 513; billion MAC/s (multiply-accumulate per second), leading FPGA devices can deliver more than 500 billion13; MAC/s x2013; thatx2019;s more than 100x faster. In the present paper attempt is made to realize the Active Controller using the Xilinx System Generator [3] on VIRTEX - 4 FPGA. System Generator is a DSP design tool from Xilinx that enables the use of The MathWorks model-based design environment, Simulink for FPGA design. Designs are captured in the DSP13; friendly Simulink modeling environment using a Xilinx specific blockset. All of the downstream FPGA13; implementation steps including Synthesis, Place and route are automatically performed to generate an FPGA13; programming file. Single channel Adaptive filter amp; system identification has been successfully implemented13; amp; Hardware Co x2013; Simulation has been carried out on Virtex-4 FPGA [4] using the XtremeDSP Development kit [5]. The methodology amp; results of this novel study are brought out in this paper

Design and development of high voltage high power operational amplifier using thick film technology

Applications of power operational amplifiers (opamps) are increasing day by day in the industry as they are used in audio amplifiers, Piezo transducer systems and the electron deflection systems. Power operational amplifiers have all the features of a general purpose opamp except the additional power handling capability. The power handling feature can be achieved using an external circuitry around a regular opamp. Normally power opamps can deliver current more than 50mA and can operate on the supply voltage more than ±25 V. This paper gives the details of one of the power opamps developed to drive the Piezo Actuators for Active Vibration Control (AVC) of aircraft/aerospace structures. The designed power opamp will work on±200V supply voltage and can deliver 200mA current

Ground Resonance Test and Response analysis of HS 748 aircraft a Preliminary report

The report deals with the preliminary results obtainer from the ground resonance test and response analysis of I1S 74" Aircraft. Comparisons of wing natural frequencies obtained from different excitations have: been made. Modal analysis results the wing are also enclosed . Recommendation for further tests the present and modified configurations of the aircraft have been include

Design and Development of Instrumentation for Active Vibration Control of Smart Aerospace Structures

Active vibration control of aerospace structures using smart concept is one of the potential areas of application, the successful implementation of which requires design, development of instrumentation. electronics, digital signal processing techniques, computers, control system, robust control law, structure with built-in sensors and actuators coupled with good analytical and system identification studies, This paper essentially deals with some of the above issues and requirements. Further, it focuses on the design, development of instrumentation catering to piezos being used as sensors and actuators on the host structure to achieve active vibration control. The implementation of active vibration control for a single channel is explained in detail. The paper concludes with the description of adaptation of the above for multi-channel vibration control

Floating point arithmetic routines for single channel microprocessor based vibration test system

The architecture of the microprocessors such as 8085/Z-8O are designed to handle integer arithmetic and do not have 13; facilities to handle real numbers. In the present application the software development for the 8085/Z-80 based vibration test and analysis system calls for extensive real number representation. With this in view as well as to achieve higher dynamic range (for better resolution of the vibratory signal) development of floating point arithmetic routines almost become mandatory. This document explains in detail different floating point arithmetic routines developed for a 8085/Z-80 processor

Application of video image processing to Aerospace Vibration Studies - A progress report

The report deals with the progress registered in the project for the period June, 1990 to Feb ., 1991, to be presented at the AR amp; DB Structures Panel

Morbidity patterns among rice mill workers: A cross sectional study

Background: India, a land of agriculture, has formed the scaffolding for many agro-based industries. Morbidity is more common among these industrial workers; hence, this study was conducted. Objectives: To study the morbidity pattern among the rice mill workers and the relationship between duration (years) of working and their morbid status. Study Design: A cross-sectional study. Materials and Methods: A pre-structured questionnaire was used to record the necessary information such as clinical history, sociodemographic profile, findings of clinical examination and performance of peak expiratory flow rate (PEFR). The study was conducted in three rice mills in an urban area under Urban Health Training Centre (UHTC), Department of Community Medicine, SSMC, Tumkur. A total of 75 workers were recruited for the study. The study was conducted in the month of October. Statistical analysis was done using Chi-square test. Results: Among these 75 workers, 42.66% had respiratory morbidity; among them, 10.66% had PEFR less than 200L/min. 26.66% had low backache and knee joint pain and 20% had generalized / musculo skeleton pain. 6.6% suffered from allergic conjunctivitis and 4% had skin allergy. Conclusion: High Prevalence of respiratory morbidity (42.66%) and 8 (10.66%) workers with decreased PEFR were found. It also showed that there was statistically significant relationship between duration (years) of working and respiratory morbid condition. This condition can be prevented by good health education and appropriate usage of safety devices, and further studies are recommended