The effects of pump pulse fluence on the output energy and amplified spontaneous emission of a femtosecond regenerative amplifier

In this paper, the effects of pump pulse fluence on the output energy and amplified spontaneous emission (ASE) of a femtosecond regenerative amplifier are investigated. One can easily enhance the output energy of laser amplifiers by increasing their pump fluence. This in turn can increase the ASE and reduce the performance of amplifiers in terms of output beam quality, beam stability, etc. This effect would eventually lead to what is called ‘temporal intensity contrast deterioration’. In this work, it is shown that an optimum state of the pump pulse fluence can indeed optimize the amount of the output energy from a regenerative amplifier without much reducing the performance of the amplifier due to the higher ASE. Temporal gain characteristics were employed to achieve this optimum value for a better design, performance, and maintenance of femtosecond laser amplifiers. The results of the current study can be effectively used in designing a wide range of regenerative amplifiers for femtosecond pulses.

IMPROVEMENT OF HELIUM IONS BEAM FORMATION AND TRANSPORT SYSTEM

Works on improvement of a beam formation and transport system from an accelerating section output to the target complex on NSC KIPT helium ions linear accelerator with output energy of 4 MeV, used for carrying out of radiating researches are continued. Results of researches spent with electromagnetic quadrupole lenses, forming a triplet are presented. Experiments with injected (120 keV) and accelerated (4 MeV) helium ions beams by means of advanced beam formation and transport system to a target are continued. The proposal on decrease in thermal loading of a triplet is formulated.

Synergy between sectoral output, energy and CO2 emission: a panel cointegration analysis of South Asia

Purpose The purpose of this study is to investigate the synergy between sectoral output, energy use and CO2 emission with other factors for a panel of South Asian economies including Afghanistan, Bangladesh, Bhutan, India, Pakistan, Maldives, Nepal and Sri Lanka. Design/methodology/approach The analysis is done using annual panel data from 1980–2019 using dynamic ordinary least squares (DOLS), fully modified OLS (FMOLS) and Toda-Yamamoto techniques. Findings Empirical findings reveal the existence of a statistically significant long-run cointegrating relationship between energy use, sectoral output such as agricultural, industry and service gross domestic product (GDP), globalization, urbanization and CO2 emission. DOLS and FMOLS result posits that in the case of the South Asian region agriculture GDP does not contribute to increasing CO2 emission while service and industrial GDP is responsible for increasing CO2 emission along with urban population, energy use and to some extent globalization. More remarkably, the contribution of the service GDP is greater than the other two sectoral outputs in increasing CO2 emission with a feedback hypothesis. Practical implications As CO2 emission is a global phenomenon with a cross-boundary effect, these empirical findings might contribute to formulating implementable energy and environmental policies to sustain growth, as well as to protect the environment in the regional context. Originality/value The study contributes to the literature by providing an empirical investigation of South Asia incorporating the contribution of sectoral output to understand the potential contribution of each sector on energy and emission. This is the first study on the South Asian context from the perspective of sectoral output, energy and emission.

Review of the Yb3+:ScBO3 Laser Crystal Growth, Characterization, and Laser Applications

Passive Q-switching is an effective approach for generating pulsed lasers, owing to its compact and additional modulation-free design. However, to compare favorably with active Q-switching and multi-stage amplification, the output energy needs to be enhanced for practical applications. Kramers Ytterbium ion (Yb3+)-doped borate crystals, with their excellent energy storage capacity, have been proven to be high-potential laser gain mediums for achieving pulsed lasers with moderate and high output energy using passive Q-switching technology. In this study, the growth, characterization, and laser generation of one Yb3+-doped borate crystal, the Yb3+:ScBO3 crystal, are systematically reviewed. The continuous-wave and passive Q-switching laser characteristics are presented in detail, and the self-pulsations derived from intrinsic ground-state reabsorption are also demonstrated. The specific characteristics and experiments confirm the potential of the Yb3+:ScBO3 crystal for future pulsed laser applications with moderate or even high energy output.

Energy Budgeting of Paddy-Pulse Cropping System in Bhadrak District of Odisha and Assessment of Emission from Paddy Straw Burning

Energy auditing of an existing production system helps to assess its energy-use and energy efficiency. The average input energy of paddy-black gram (PB) cropping system (19,862.01 MJ.ha-1) was higher than paddy-green gram (PG) (18,972.34 MJ.ha-1) cropping system in Bhadrak, Odisha. Harvesting and transport operation required highest operational energy for PG (35.57%) and PB (41.20%) farms; while, threshing and winnowing consumed the second highest input energy with 21.34% and 22.71% for PG and PB farms, followed by land preparation with 21.87% and 20.10% respectively. Linear regression data of PG and PB systems showed significant effect (p<0.05) of predictors with R2 values of 87.70% and 82.20% for total output energy and grain energy, respectively; confirming a good fit among the data. The output energy of PB cropping system was 13.91% higher than that of PG cropping system. The PB cropping system, with energy utilisation efficiency (EUE) of 10.31 and 11.82, was more energy-efficient than PG system with EUE of 9.32 and 11.01 for “NC” and “C” farms, respectively. The net energy return of PBC farm was highest with 2,04,505.31 MJ.ha-1. Amongst various pollutants emitted from paddy straw burning in Odisha; CO2 (5,51,296.0 Mg.yr-1), CO (13,102.72 Mg.yr-1), and TPM (4,908.80 Mg.yr-1) had highest share. The quantity of major GHGs (N2 O, CH4 ) released into the atmosphere through paddy straw burning was estimated as 26.43 Mg.yr-1 and 453.12 Mg.yr-1, respectively. Use of straw baler can prevent straw burning, and reduce emission from paddy fields by 2805.54 kg.ha-1 of CO2 and 66.69 kg.ha-1 of CO, 5.96 kg.ha-1 of NOx , 24.98 kg.ha-1 of TPM. Alternatively, use of mulcher can also reduce emission from paddy fields by 2924.44 kg.ha-1 of CO2 and 69.51 kg.ha-1 of CO, 6.21 kg.ha-1 of NOx , 26.04 kg.ha-1 of TPM. The cost of operation of a baler and mulcher were 8,617.0 ₹ ha-1 and 2,543.0 ₹ ha-1, respectively. Input energy and energy saved in paddy fields by baler were 820.0 MJ.ha-1 and 16,928.0 MJ.ha-1; and 266.0 MJ.ha-1 and 24,458.0 MJ.ha-1 by mulcher, respectively

4-output Programmable Spin Wave Logic Gate

To bring Spin Wave (SW) based computing paradigm into practice and develop ultra low power Magnonic circuits and computation platforms, one needs basic logic gates that operate and can be cascaded within the SW domain without requiring back and forth conversion between the SW and voltage domains. To achieve this, SW gates have to possess intrinsic fanout capabilities, be input-output data representation coherent, and reconfigurable. In this paper, we address the first and the last requirements and propose a novel 4-output programmable SW logic. First, we introduce the gate structure and demonstrate that, by adjusting the gate output detection method, it can parallelly evaluate any 4-element subset of the 2-input Boolean function set AND, NAND, OR, NOR, XOR, and XNOR. Furthermore, we adjust the structure such that all its 4 outputs produce SWs with the same energy and demonstrate that it can evaluate Boolean function sets while providing fanout capabilities ranging from 1 to 4. We validate our approach by instantiating and simulating different gate configurations such as 4-output AND/OR, 4-output XOR/XNOR, output energy balanced 4-output AND/OR, and output energy balanced 4-output XOR/XNOR by means of Object Oriented Micromagnetic Framework (OOMMF) simulations. Finally, we evaluate the performance of our proposal in terms of delay and energy consumption and compare it against existing state-of-the-art SW and 16nm CMOS counterparts. The results indicate that for the same functionality, our approach provides 3x and 16x energy reduction, when compared with conventional SW and 16nm CMOS implementations, respectively.