Design of a dual OPAMP low offset integrator system for plasma reactor

In a fusion reactor, where tokamaks are used to confine the plasma using toroidal and poloidal magnetic fields, highly accurate magnetic measurements are a necessity for automatic control. However, due to extremities in temperature, acquiring uncorrupted signals become a challenging task. Presented in this thesis is a design of a twin operational amplifier based low offset integrating system to eliminate any error in measurement due to temperature dependent DC offset. This integrator system comprises mainly three stages after the inductive sensor. The first stage consists of a dual integrator in which the output signal from the sensor was fed to one integrator and the input terminals of the other integrator were grounded. An instrumentation amplifier which has a very high common mode rejection ratio and large input impedance was implemented in the second stage to find the differential signal between the outputs of the two integrators. Any noise arising in the environment was eliminated in the next stage by a Digital Signal Processor based Finite Impulse Response Low-Pass Filter. The first two stages of the design were simulated by using Multisim Circuit Design Suite. The low-pass filtering stage was realized on a Texas Instruments TMS320C6713 starter kit using Kaiser Windowing technique to achieve a sharp cut-off at 780Hz. To obtain a full layout of the operational amplifier based design Cadence Electronic Design Automation UMC_180 nm tool was used. The primary objective of DC offset elimination was verified through the results. KEY WORDS: Inductive Sensor, Operational Amplifier, Integrator, Instrumentation Amplifier, Low-pass Filte

Economic contribution of forest sector in Oklahoma in 2020

The Oklahoma Cooperative Extension Service periodically issues revisions to its publications. The most current edition is made available. For access to an earlier edition, if available for this title, please contact the Oklahoma State University Library Archives by email at [email protected] or by phone at 405-744-6311

Stage specific consumption and utilization of aphids, conspecific and heterospecific eggs by two species of Coccinella (Coleoptera: Coccinellidae)

Abstract. The nutritive quality of aphids, conspecific and heterospecific eggs as food for ladybirds is a controversial issue. If ladybirds find aphids more palatable than eggs then they are more likely to efficiently exploit and be biocontrol agents of aphids. If eggs of conspecific or heterospecific ladybirds are more palatable than aphids these biocontrol agents may either impede aphid pest suppression or become a threat to other species of ladybirds. Thus, prior to formulating predatory guilds of ladybirds the nutritive quality of their eggs compared to that of the target aphid needs to be determined. In this regards, the present study evaluates the nutritive quality of an ad libitum supply of: (i) pea aphid, Acyrthosiphon pisum (Harris), (ii) conspecific eggs and (iii) heterospecific eggs as food for Coccinella septempunctata (L.) and Coccinella transversalis Fabricius (Coleoptera: Coccinellidae), by determining the stage specific predation and developmental attributes of these two ladybirds reared on these diets. The conversion efficiencies and growth rates of young (first, second and third) larvae of both species of ladybirds were higher than those of fourth instar larvae and the consumption rates of fourth instar were higher than those of young larvae when fed on the three diets. When fed aphids the pre-imaginal development was faster, the consumption rates, conversion efficiencies and growth rates higher, adults bigger and mortality lower than when fed on conspecific eggs. The larvae of C. septempunctata consumed and completed their development when fed eggs of C. transversalis but the first instar larvae of C. transversalis did not consume the eggs of C. septempunctata and died of starvation. The dominance of C. septempunctata over C. transversalis in agricultural fields may be due to it consuming and utilizing aphids more efficiently and as a consequence growing faster and suffering a lower mortality along with its ability to consume and complete its development on eggs of C. transversalis. Thus, both these predators may not continue to coexist as predators of the pea aphid in agricultural fields since C. septempunctata may become a greater threat to C. transversalis in the future

Observation of Alfven wave in ICME-HSS interaction region

The Alfv\'en wave (AW) is the most common fluctuation present within the emitted solar wind from the Sun. Moreover, the interaction between interplanetary coronal mass ejection (ICME) and high-speed stream (HSS) has been observed on several occasions. However, can such interaction generate an AW? What will be the nature of AW in such a scenario remains an open question. To answer it, we have investigated an ICME-HSS interaction event observed on 21st October 1999 at 1 AU by Wind spacecraft. We have used the Wal\'en test to identify AW and estimated Elsasser variables to find the characteristics of the AWs. We explicitly find that ICME were dominant with Sunward AWs, whereas the trailing HSS has strong anti-Sunward AW. We suggest that the ICME-HSS interaction deforms the MC of the ICME, resulting in the AWs inside the MC. In addition, the existence of reconnection within the ICME early stage can also be the leading cause of the origin of AW within it

Slow and fast development in ladybirds: occurrence, effects and significance

Developmental and growth rates are known to vary in response to genetic, developmental, physiological and environmental factors. However, developmental variations that exist within a cohort under any constant rearing condition are not so well investigated. A few such prominent polymorphisms have been studied, but not the subtle ones. The current study investigates the presence of such varying rates of development, slow and fast, in a cohort reared under constant conditions in two ladybirds, <i>Cheilomenes sexmaculata</i> and <i>Propylea dissecta</i>. Our results reveal slow and fast developers in the cohorts of each species and the ratio of slow and fast developers was similar. Slow developers showed a female biased sex ratio. The two developmental variants differed significantly in juvenile duration only in the first instar and the pupal stage, though variations in developmental time were observed in all stages. Fecundity was higher in slow developers, but developmental rates did not affect egg viability. The similar ratio in both ladybirds indicates it to be a result of either presence of a constant ratio across species or an effect of the similar rearing environment

Maternal body size and age govern reproduction and offspring phenotype in the zig-zag ladybird beetle (Menochilus sexmaculatus)

Maternal effects are possible channels through which mothers provision their offspring differentially, thereby affecting offspring phenotype. We investigated maternal effects in the zig-zag ladybird beetle (Menochilus sexmaculatus (Fabricius, 1781) = Cheilomenes sexmaculata (Fabricius, 1781)) in response to body size (induced by different feeding regimes during larval development) and their age within the reproductive cycle. Different-sized females were permitted to mate and were provided with daily-replenished ad libitum prey. After mating, reproductive output and developmental duration of offspring from different oviposition days were recorded. We hypothesized that small females would lay smaller and fewer eggs than larger females, and that egg mass would also reduce with increased maternal age. In our study, the larger mothers laid more eggs per day. Small and large mothers oviposited maximally at middle age. Maternal age did not influence the egg mass, although it was slightly higher in the case of older, larger females. Offspring from old, small and large mothers developed rapidly. This nimble development could be an adaptive strategy for the use of ephemeral aphid patches. The results of the study are indicative of this ladybird species’ ability to adjust their offspring’s life-history traits, a feature more prominent in larger females.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author