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Several solutions to the capacitated plant location problem (CPLP) commonly encountered by operations managers and researchers are evaluated. These include heuristic-based schemes, the dual ascent method and the linear programming relaxation approach. Results indicate that all methods provide accurate solutions to the CPLP.

A study was conducted to examine the application of Lagrangian relaxation functions in solving the capacitated plant location problem. The study focuses on the single source constraint provided by the location problem and considers bounds and solutions techniques. Results show that the development of a heuristic from Lagrangian problem relaxation can be used to solve combinatorial problems.

Quadratic Assignment Problems (QAPs) are the hardest of combinatorial optimization problems, with some problems of sizes of the order of 30 still remaining unsolved optimally. Solving these problems with exact optimization methods is cumbersome and hence the use of non-traditional optimization methods is advisable. The discrete version of Particle Swarm Optimization (DPSO) is a widely accepted non-conventional optimization algorithm for combinatorial optimization problems. This paper uses Taguchi's robust design approach to determine the best combination of parameters for discrete particle swarm optimization algorithm for solving quadratic assignment problems. [ABSTRACT FROM AUTHOR]

The recently evolved L-band scintillation forecast mechanism based on the characteristic features of the daytime F-region electron density fluctuations and also on the basic ionospheric conditions had been successful to a reasonable extent in forecasting the spatio-temporal map of scintillation patches. There had been a few non-compliances in the expected pattern within/outside the forecast windows. The present paper attempts to address such non-compliances and offers a plausible explanation based on neutral dynamics, especially the local time variation of vertical winds over the magnetic equator, while at the same time refining the earlier stipulated background ionospheric conditions. With the above refinements, it is anticipated that the forecast mechanism would become very robust. The present results highlight the importance of the neutral dynamical parameters and the urgent need to concentrate on the efforts to make systematic measurements of the same in order to characterize their variability. [ABSTRACT FROM AUTHOR]

The measurements carried out by Chandra׳s Altitudinal Composition Explorer (CHACE) onboard the Moon Impact Probe (MIP) of Chandrayaan I mission is used to obtain information on the 2-D distribution of the lunar atmospheric H 2 by a novel approach that makes use of the basic fact that the Moon has a Surface Boundary Exosphere (SBE).These are the ‘first’ daytime in situ measurements of lunar H 2 covering the 20°S to 88°S latitude region centered ~14°E longitude. A critical examination of the observed spatial features of the surface number density of H 2 vis-à-vis the surface topography delineated from the Lunar Laser Ranging Instrument (LLRI) in the main orbiter Chandrayaan-I, indicates that that lunar surface process may be important in introducing small scale variations in the H 2 number density. Another constituent which exhibited spatial variation in the observed partial pressure is 40 Ar and it was hypothesized that it is indicative of the spatial heterogeneity in the radiogenic activity of the Lunar interior ( Sridharan et al., 2013a ). The absolute number density at the surface and also the latitude/altitude variation of the densities that are reported for the first time, highlight the complexities of the sunlit lunar atmosphere. [ABSTRACT FROM AUTHOR]

After a fairly successful attempt to forecast the temporal evolution of L-band scintillation over a given location, Trivandrum (8.5° N, 76.91° E, dip latitude 0.5° N) (Sridharan et al., 2012, J. Atmos. Sol. Terr. Phys. 80 230–238; Bagiya et al., 2014, J. Atmos. Sol. Terr. Phys. 110–111, 15–22), an attempt has been made here to generate the spatial–temporal maps of the occurrence pattern of L-band scintillation over the Indian region. To start with, the day time fluctuations in [f 0 F 2 ] 2 are used to forecast the temporal evolution of perturbations during the course of the night over Trivandrum. Similar to the earlier studies, here too it is taken that the electron density perturbations retain their characteristics throughout night and traverse with a uniform velocity. This implies that when the integrity of wave train of electron density perturbations is retained, any particular feature that passes over Trivandrum would have crossed over another location west of Trivandrum at an earlier time only dictated by the zonal velocity. With this assumption it becomes feasible to generate the probable spatial and temporal pattern of L-band scintillation. The consequences/limitations of the above assumptions are discussed in detail. The observed relation between the total duration of spread-F and the base height of the F-region (h'F) at 1930 LT has been explained in terms of the favourable background neutral atmospheric conditions. Following Bagiya et al. (2013, J. Geophys. Res. 118, 1–8), the relation between h'F at 1930 LT and the probable maximum latitudinal extent of the spread-F enables specification of the upper limit for the latitudes likely to be affected by the scintillation. It is believed that the presented results hold enough potential to generate the reliable L-band scintillation forecast maps and provide the necessary alerts to the satellite based air navigation users. [ABSTRACT FROM AUTHOR]

A critical evaluation of the novel method suggested by Sridharan et al. (2012) to forecast L-band scintillation is made using the results from a special campaign conducted from Trivandrum (8.5°N, 76.91°E, dip latitude 0.5°N), India, during April 2012. The significance of the campaign lies in the fact that, (1) efforts are made to minimise the uncertainties due to the movement of the satellite platform (TEC and S4 observations from GNSS satellites) by choosing a recently launched GSAT-8 geostationary satellite for ionospheric scintillation in L1 band, (2) unlike the previous study (Sridharan et al., 2012) wherein the GPS derived TEC fluctuations were treated as representative of ionospheric perturbations, in the present exercise, the fluctuating component of the foF2 data from the ground based digital Ionosonde have been taken as a measure of the perturbations and (3) though both the GSAT and Ionosonde are stationary, still the ionospheric regions they represent are physically separated and in order to correlate the scintillation over the GSAT location to the forecast perturbations over the ionosonde location, the required zonal velocity of the perturbations/irregularities is estimated using GSAT and GPS scintillation data during one of the close-by GPS passes and this is taken to represent the particular solar epoch and season. Following the earlier method of Sridharan et al. (2012) the relative amplitudes and phase integrity of the perturbations have been maintained and extended throughout night. By adopting the above changes, it has been noted that the forecasting capability of L band scintillation has remarkably improved vindicating the role of perturbations in the evolution of the scintillation, thus making it more useful for practical applications. The nonoccurrence of scintillation on occasions in the prescribed time windows has also been understood based on the changes in the background conditions. A threshold upward velocity for the evening F-region as early as 1730–1830LT, has been worked out to be 5ms−1 for the ESF to get triggered and for its sustenance, a plasma scale length of <20km along with a critical base height (h׳F) of 225km have been evaluated as necessary background conditions. [ABSTRACT FROM AUTHOR]

Abstract: In the past, clues on the potential radiogenic activity of the lunar interior have been obtained from the isotopic composition of noble gases like Argon. Excess Argon (40) relative to Argon (36), as compared to the solar wind composition, is generally ascribed to the radiogenic activity of the lunar interior. Almost all the previous estimates were based on, ‘on-the-spot’ measurements from the landing sites. Relative concentration of the isotopes of 40Ar and 36Ar along a meridian by the Chandra’s Altitudinal Composition Explorer (CHACE) experiment, on the Moon Impact Probe (MIP) of India’s first mission to Moon, has independently yielded clues on the possible spatial heterogeneity in the radiogenic activity of the lunar interior in addition to providing indicative ‘antiquity’ of the lunar surface along the ground track over the near side of the moon. These results are shown to broadly corroborate the independent topography measurements by the Lunar Laser Ranging Instrument (LLRI) in the main orbiter Chandrayaan-1. The unique combination of these experiments provided high spatial resolution data while indicating the possible close linkages between the lunar interior and the lunar ambience. [Copyright &y& Elsevier]

Abstract: One of the recent developments in the form of a novel probe for simultaneous in-situ measurements of Electron density and Neutral Wind (ENWi) parameters was extensively made use of during the annular solar eclipse that passed right over the magnetic dip equatorial station, Trivandrum in India. The response of the equatorial ionosphere to the annular solar eclipse of January 2010 is investigated using the data from ENWi and other ground based instruments like digital Ionosonde, HF radar, magnetometer etc. Significant effects on the neutral wind components and electron densities during the peak phase of the eclipse are brought out by the ENWi data. A clear reversal in the zonal neutral wind is observed during the rocket flights at the peak phase of the eclipse as well as in the flight conducted 3h later. The ground magnetic field measurements revealed the reversal of electrojet during the eclipse alongwith blanketing Es layers vindicating the earlier hypothesis that blanketing Es layers manifest over magnetic equatorial regions only during periods of either weak or reversed electrojet (counter electrojet). The HF radar results independently substantiate the in situ measurements with regard to the location of the irregularities and their Doppler velocities. The regional scale changes that have been brought about by the Solar eclipse both in the neutral and ionized medium and the consequent electrodynamics are highlighted. [Copyright &y& Elsevier]

Abstract: Forecasting the occurrence of L-band scintillations has been a challenging task and, this challenge has been tackled by evolving a simple method using GPS-TEC data. For given background conditions, it has been shown that the fluctuations in the GPS-TEC truly represent the characteristic features of the perturbations that are responsible for the initiation of the plasma instability that finally culminates in to the observed irregularities. The close linkage between the perturbation features and the evolutionary pattern of the scintillations enable us to forecast ‘when’, and ‘for how long’ the L-band scintillations would occur, in addition to their ‘occurrence pattern’. The first of their kind of results take us a step closer towards operational forecasting of L-band scintillations for real time navigational purposes. [Copyright &y& Elsevier]

Abstract: A novel method for the in-situ measurement of thermospheric and ionospheric parameters has successfully been tried out by means of a new probe ENWi. The probe has been designed for neutral wind and electron density measurements up to ∼115km. ENWi was successfully flight tested on sounding rockets from Thumba, India during the recent annular solar eclipse (January 2010) that passed right over the rocket range. The present paper deals with the basic concept that has been successfully put to test for neutral wind measurements in a critical height region, thus highlighting its potential to fill up a void in the Aeronomic studies. [Copyright &y& Elsevier]

Abstract: The altitudinal/latitudinal profile of the lunar atmospheric composition on the sunlit side was unraveled for the first time by the Chandra’s Altitudinal Composition Explorer (CHACE) on the Moon Impact Probe, a standalone micro-satellite that impacted at the lunar south pole, as a part of the first Indian mission to Moon, Chandrayaan-1. Systematic measurements were carried out during the descent phase of the impactor with an altitude resolution of ∼250m and a latitudinal resolution of ∼0.1°. The overall pressure on the dayside and the neutral composition in the mass range 1–100amu have been measured by identifying 44 and 18amu as the dominant constituents. Significant amounts of heavier (>50amu) species also have been detected, the details of which are presented and discussed. [Copyright &y& Elsevier]

Abstract: Direct detection of water in its vapour phase in the tenuous lunar environment through in situ measurements carried out by the Chandra’s Altitudinal Composition Explorer (CHACE) payload, onboard the Moon Impact Probe (MIP) of Chandrayaan I mission vindicates the presence of water on the surface of the moon in form of ice at higher lunar latitudes inferred from IR absorption spectroscopy, (especially that of OH), by the Moon Mineralogy Mapper (M3) of Chandrayaan I. The quadrupole mass spectrometer based payload, CHACE, sampled the lunar neutral atmosphere every 4s with a broad latitudinal (∼40°N to 90°S, with a resolution of ∼0.1°) and altitudinal (from 98km up to impact on the lunar surface with a resolution of ∼0.25km) coverage in the sunlit side of the moon for the first time. These two (CHACE and M3) complementary experiments are shown to collectively provide unambiguous signatures for the distribution of water in solid and gaseous phases in Earth’s moon. [Copyright &y& Elsevier]

The traditional distribution planning problem in a supply chain has often been studied mainly with a focus on economic benefits. The growing concern about the effects of anthropogenic pollutions has forced researchers and supply chain practitioners to address the socio-environmental concerns. This research study focuses on incorporating the environmental impact on route design problem. In this work, the aim is to integrate both the objectives, namely economic cost and emission cost reduction for a capacitated multi-depot green vehicle routing problem. The proposed models are a significant contribution to the field of research in green vehicle routing problem at the operational level. The formulated integer linear programming model is solved for a set of small scale instances using LINGO solver. A computationally efficient Ant Colony Optimization (ACO) based meta-heuristic is developed for solving both small scale and large scale problem instances in reasonable amount of time. For solving large scale instances, the performance of the proposed ACO based meta-heuristic is improved by integrating it with a variable neighbourhood search. [ABSTRACT FROM AUTHOR]