Observation of coherent population trapping in a V-type two-electron system

We observe coherent population trapping (CPT) in a two-electron atom---$^{174}$Yb---using the $\rm {^1S_0,F=0} \rightarrow {^3P_1,F'=1}$ transition. CPT is not possible for such a transition according to one-electron theory because the magnetic sublevels form a V-type system, but in a two-electron atom like Yb, the interaction of the electrons transforms the level structure into a $\Lambda$-type system, which allows the formation of a dark state and hence the observation of CPT. Since the two levels involved are degenerate, we use a magnetic field to lift the degeneracy. The single fluorescence dip then splits into five dips---the central unshifted one corresponds to coherent population oscillation, while the outer four are due to CPT. The linewidth of the CPT resonance is about 300 kHz and is limited by the natural linewidth of the excited state, which is to be expected because the excited state is involved in the formation of the dark state.Comment: 5 pages, 5 figures, 2 table

Analysis of Nebivolol hydrochloride and Valsartan in Pharmaceutical Dosage Form by High Performance Thin Layer Chromatographic Method

A simple, accurate and precise high performance thin layer chromatographic method has been developed for the estimation of Valsartan and Nebivolol hydrochloride simultaneously from a tablet dosage form. The method employed silica gel 60 F254 pre-coated plates as stationary phase and a mixture of Ethyl acetate: Methanol: Ammonia (6.5:2.5:0.5 %v/v/v) as mobile phase. Densitometric scanning was performed at 280 nm using a Camag TLC scanner 3. Beer’s law was obeyed in the concentration range of 800ng/spot-2400ng/spot for Nebivolol hydrochloride and 200ng/spot-1000ng/spot for Valsartan. The Retention factor for Nebivolol hydrochloride is 0.75 ± 0.04 and is 0.27 ± 0.01 for Valsartan . The method was validated as per ICH Guidelines, proving its utility in estimation of Valsartan and Nebivolol hydrochloride in combined dosage form

Observation of the nuclear magnetic octupole moment of 173^{173}Yb from precise measurements of hyperfine structure in the 3P2{^3P}_2 state

We measure hyperfine structure in the metastable ${^3P}_2$ state of $^{173}$Yb and extract the nuclear magnetic octupole moment. We populate the state using dipole-allowed transitions through the ${^3P}_1$ and ${^3S}_1$ states. We measure frequencies of hyperfine transitions of the ${^3P}_2 \rightarrow {^3S}_1$ line at 770 nm using a Rb-stabilized ring cavity resonator with a precision of 200 kHz. Second-order corrections due to perturbations from the nearby ${^3P}_1$ and ${^1P}_1$ states are below 30 kHz. We obtain the hyperfine coefficients as: $A=-742.11(2)$ MHz, $B=1339.2(2)$ MHz, which represent two orders-of-magnitude improvement in precision, and $C=0.54(2)$ MHz. From atomic structure calculations, we obtain the nuclear moments: quadrupole $Q=2.46(12)$ b and octupole $\Omega=-34.4(21)$ b\,$\times \mu_N$.Comment: 5 pages, 1 figur

Assessment of potential rooftop solar PV electricity at a suburban scale, and a comparative analysis based on topographical obstruction and seasonality

Long-term climate change mitigation calls for a switch from the current global non-renewable energy system to low greenhouse gas (GHG) emission energy solutions. Many nations have started adopting energy-efficient technology as part of their climate change programs and the built environment has been identified as a key lever for reducing emissions linked to energy efficiency. Building rooftop photovoltaic (PV) system is an effective technology to reduce emissions through the use of solar energy. In recent years, rooftop PV systems have become the main source of solar-generated energy, and forecasting their output is critical when assessing a site\u27s PV energy potential. However, integrating topographical features with seasonal considerations to estimate solar PV energy is challenging. There are some studies available that estimate solar PV energy on rooftops using geospatial tool modeling, but these have limitations in functionality, accuracy, and calculation speed. This study uses a geospatial tool to assess the solar PV potential of suitable rooftops in the suburbs of Wollongong, Australia, namely, Wombarra and Cringila. The model used in this study compares the energy potential of these two suburbs based on the topographical feature (escarpment), seasonality, rooftop slope, and aspect. The digital surface model (DSM) is created using LiDAR data, and then the DSM, building footprints, and suburb boundaries data are used to calculate the solar PV energy potential. A total of 1594 buildings from two suburbs were considered. Subsequently, solar radiation modeling for four common seasons in a year and a comparison of solar radiation output, suitable rooftop area, and electricity output are being done for both suburbs. Wombarra\u27s building rooftops are shadowed by the escarpment, whereas Cringila\u27s aren\u27t. Even though the weather in both suburbs is similar, the escarpment\u27s shadow affects solar PV energy output. Wombarra has 178 kWh/m2/building lesser yearly solar radiation than Cringila. Hence, Cringila offers more solar rooftop installation potential per building. The average annual potential electricity generation per dwelling in Wombarra is 20.6 kWh/m2/day, and the same for Cringila is 27.6 kWh/m2/day. The outcome reveals that 1352 building rooftops, with a usable area of 75481 m2, are the best locations for installing solar panels. According to the Australian Government\u27s Energy Made Easy statistics, the annual electricity consumption per household in Wollongong is 5707.6 kWh (Australian Energy Regulator 2022). The estimated yearly electricity production is 12705 Mwh (Wombarra: 2778.3 Mwh, Cringila: 9926.7 Mwh), which would be sufficient to meet local electricity consumption. An excess of 17% from Wombarra and 48% from Cringila can be exported back to the grid, which can be used by 3 neighbouring areas. Tiseo (2021) reported that Australia\u27s power sector released 656.4 grams/kWh of CO2 in 2020. Therefore, solar PV panels on all suitable rooftops of both suburbs could prevent 8339.5 tonnes of CO2 emissions. To achieve the goal of clean energy, future development can use the study\u27s findings as a guide. The proposed approach can assist in influencing policies and subsidies to boost deployment. This research can be made more in-depth by taking into account social and economic factors like consumer choices and return on investment, and physically inspecting specific building rooftop impediments

High Dependency on Quacks – Is There a Gap in the Public Health Care Delivery System? Reflections from a District Located in the Thar Desert (India)

This paper tries to analyse the availability and role of public health care services provided by the public sector in India. In addition, it also explores the reasons behind the high dependency on quacks in the study area. Data was acquired through in-depth interviews of 610 respondents with the help of a structured questionnaire from September to December 2010. Here, an attempt has been made to probe the pattern of utilization of health care services available at public health facilities by the sample respondents. It has been assessed in relation to socio-economic and demographic characteristics of the interviewees which exert significant influence on the utilization of health care facilities. The study finds that the number of CHCs/PHCs/Sub-centres in the study area is not adequate to meet the health needs (medical advice or treatment) of entire the population. The results recommend improving the availability and accessibility of health care facilities in the area under study

Development of a heterogeneously catalyzed chemical process to produce biodiesel

It is well known fact that energy is a big issue for this world and substantial amount of research is going on worldwide for alternative fuels that are environmentally friendly, especially because of the fact that crude petroleum reserves are dwindling. Also, research on alternative fuels is essential for increased energy security. Biodiesel is a renewable, biodegradable, and nontoxic fuel. At present, when homogeneous catalysts are used, biodiesel is primarily produced in batch reactors in which the required energy is provided by heating accompanied by mechanical mixing. Alternatively, ultrasonic processing could be an effective way to attain required mixing while providing the necessary activation energy. We found that, using ultrasonication, a biodiesel yield in excess of 99% can be achieved in a short time duration of five minutes or less in comparison to one hour or more using conventional batch reactor systems. Homogeneous acid or base catalysts dissolve fully in the glycerol layer and partially in the fatty acid methyl esters (biodiesel) layer during the triglyceride transesterification process. Heterogeneous (solid) catalysts, on the other hand, can prevent catalyst contamination making product separation much easier. In the present work, one of the objective was to determine the transesterification kinetics of different pure metal oxide catalysts, mixed metal oxide catalysts, layered double hydroxides with their corresponding yield is presented. It was found that heterogeneous catalysts require much higher temperatures (215oC) and pressures to achieve acceptable conversion levels compared to homogeneous catalysts. For some of the mixed metal oxide solid catalysts a conversion level of 99% was observed. The present study also deals with the catalyst characterization on the basis of their acidity/ basicity and site strength, and surface area. Finally the deoxygenation of fatty acid methyl esters was carried out in order to upgrade the biodiesel. As a result, several aliphatic and aromatic hydrocarbons were detected in the mass spectrometric studies. This dissertation consists of five chapters. Chapter I presents a brief introduction to biodiesel production and the objectives of the study. Chapter II contains a review of literature. Chapter III contains the materials and methods used in this study. In this chapter different principles and theories will be mentioned with regard to the use of ultrasonication towards biodiesel production, reaction kinetics of biodiesel production, catalyst characterizations and thermodynamic analysis of deoxygenation of fatty acid methyl esters. Chapter IV presents the results and its discussions. Finally, Chapter V discusses the summary and conclusions of the study

Precise measurement of hyperfine structure in the 2P1/2{2P}_{1/2} state of 7^{7}Li using saturated-absorption spectroscopy

We report a precise measurement of the hyperfine interval in the ${2P}_{1/2}$ state of $^{7}$Li. The transition from the ground state ($D_1$ line) is accessed using a diode laser and the technique of saturated-absorption spectroscopy in hot Li vapor. The interval is measured by locking an acousto-optic modulator to the frequency difference between the two hyperfine peaks. The measured interval of 92.040(6)~MHz is consistent with an earlier measurement reported by us using an atomic-beam spectrometer [Das and Natarajan, J.\ Phys.\ B {\bf 41}, 035001 (2008)]. The interval yields the magnetic dipole constant in the $P_{1/2}$ state as $A=46.047(3)$, which is discrepant from theoretical calculations by $>80$~kHz.Comment: 5 pages, 3 figure