Absorption spectrum in the wings of the potassium second resonance doublet broadened by helium

We have measured the reduced absorption coefficients occurring in the wings of the potassium 4S-5P doublet lines at 404.414 nm and at 404.720 nm broadened by helium gas at pressures of several hundred Torr. At the experimental temperature of 900 K, we have detected a shoulder-like broadening feature on the blue wing of the doublet which is relatively flat between 401.8 nm and 402.8 nm and which drops off rapidly for shorter wavelengths, corresponding to absorption from the X doublet Sigma+ state to the C doublet Sigma+ state of the K-He quasimolecule. The accurate measurements of the line profiles in the present work will sharply constrain future calculations of potential energy surfaces and transition dipole moments correlating to the asymptotes He-K(5p), He-K(5s), and He-K(3d).Comment: 2 figure

Cusp satellite bands in the spectrum of Cs

We report measurements and a theoretical explanation of the cusp-shaped satellite bands in the blue wing of the cesium D2 resonance line which have been observed for the first time. The bands are identified as $1 ^{3}\!\Pi _{g}(2_{g},1_{g},0_{g}^{+},0_{g}^{-})\leftarrow a ^{3}\Sigma _{u}^{+}(1_{u},0_{u}^{+})$ transitions where the upper state dissociates into the 6 2P$_{3/2} + 6 ^{2}$S1/2 atomic asymptote. The experiment has been performed using a standard absorption setup, computer controlled data acquisition and computer data processing. We have shown that the peculiar shape of the $1 ^{3}\!\Pi _{g}(0_{g}^{+})-a ^{3}\Sigma _{u}^{+}(1_{u})$ difference-potential curve is solely responsible for the spectrum containing the cusp-shaped satellite bands. The appearance of these satellite bands has been discussed and explained relating the theory of satellite bands to the catastrophe theory. The shape of the line wing and of the satellite bands have been calculated using the Fourier transform technique. To ensure a more stringent comparison between the experimental and the theoretical spectrum, we have analyzed and compared the derivatives of the measured and the calculated satellite band shape. On the contrary to the customary direct comparison between the measured and the calculated absorption coefficient, the derivative clearly shows all differences and resemblances between satellite band profiles. The degree of coincidence of the experimentally observed and the theoretically calculated satellite band shape can be used as an ultimate check on the assessment of the quality of potential-energy curves involved in the formation of satellite bands

MAXIMA IN POTENTIAL CURVES OF Cs2Cs_{2} MOLECULES

Goran Pichler is a JILA visiting fellow 1977-1978. Permanent address: Institute of Physics, Zagreb, Yugoslavia.""Author Institution: Joint Institute for Laboratory Astrophysics; Institute of Physics; Institute of Physics, Instit\'ut f\'ur Experimentalphysik der Universit\'at KielA discussion is provided for the explanation of the five salellite bands observed in the very for wings of the self-broadened D1 and D2 cesium resonance lines. It seems that the Van der Waals type interaction, avoided crossings and exchange interaction contribute to a bending downwards of initially repulsive resonance interaction curves $2_{g}, 1_{g}, 1_{u}, 0_{g}^{-}$ and $0_{g-}^{+}$. This results in the formation of the five maxima, which correspond to the five observed satellites in the far quasistatic wings. One of the maxima is identified as a hump in the $B^{1}\Pi_{u}$ (or $1_{u}$) potential curve with the relevant height above $^{2}P_{3/2} + ^{2}S_{1/2}$ level of about $250\, cm^{-1}$, which well agrees with the height of about $254\, cm^{-1}$ obtained by the extrapolation procedure from the $x^{1}\Sigma_{g}^{+} - B^{1}\Pi_{u}$ bands of the $Cs_{2}$ molecule by Kusch and Hessel. Possible implications of the present model Lo other alkali dimers will be discussed

Effect of COVID-19 on biodiesel industry: A case study in Indonesia and Malaysia

Indonesia and Malaysia are currently holding prominent roles in the global palm oil market. Both countries are the top two palm oil producers in the world and have ambitious targets to increase the palm oil-based biodiesel mandate. In Indonesia, the current programme of blending 20 per cent palm oil into 80 per cent diesel (B20) increases to B30 in 2020. Likewise, Malaysia plans to increase its biodiesel mandate from B10 to B20 in 2020. However, the outbreak of COVID-19 has infected millions and brought the global economy to a near-deadlock. The effect is particularly severe in the fuel industry owing to movement restrictions and the historic drop in oil prices. Evaluating the impact of the COVID-19 on the biodiesel industry is crucial for policymakers but challenging as the pandemic has evolved with intense speed. This article aims to discuss the impact of COVID-19 on the Indonesian and Malaysian biodiesel industry. In addition to that, a number of possible solutions to overcome the challenges were addressed and proposed. Despite severely affected by COVID-19, both Indonesia and Malaysia can use this momentum to improve and strengthen their biodiesel sector. Given its fiscal deficit, Indonesia should postpone its biodiesel blending mandate as the subsidy to support the programme can worsen the country’s financial stability. In Malaysia, where labour shortage is prevalent, modernising plantations with automated equipment, for instance, could potentially remove the dirty and dangerous stereotypes associated with plantation works, thus attracting more locals to work in the palm oil plantation and solving the labour shortage. This paper also briefly addresses the adoption of Industry 4.0 and Circular Economy for the palm oil biodiesel industry

Review of artificial neural networks for gasoline, diesel and homogeneous charge compression ignition engine: Review of ANN for gasoline, diesel and HCCI engine

In automotive applications, artificial neural network (ANN) is now considered as a favorable prediction tool. Since it does not need an understanding of the system or its underlying physics, an ANN model can be beneficial especially when the system is too complicated, and it is too costly to model it using a simulation program. Therefore, using ANN to model an internal combustion engine has been a growing research area in the last decade. Despite its promising capabilities, the use of ANN for engine applications needs deeper examination and further improvement. Research in ANN may reach its maturity and be saturated if the same approach is applied repeatedly with the same network type, training algorithm and input–output parameters. This review article critically discusses recent application of ANN in ICE. The discussion does not only include its use in the conventional engine (gasoline and diesel engine), but it also covers the ANN application in advanced combustion technology i.e., homogeneous charge compression ignition (HCCI) engine. Overall, ANN has been successfully applied and it now becomes an indispensable tool to rapidly predict engine performance, combustion and emission characteristics. Practical implications and recommendations for future studies are presented at the end of this review