Passenger facility charge vs. airport improvement program funds: A dynamic network DEA analysis for U.S. airport financing

Chang, Y.T.,Park, H.,Zou, B.,Kafle, N. Elsevier Science Ltd ; Pergamon ; Elsevier Science 2016 TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANS Vol.88 No.-

<P>Passenger Facility Charge (PFC) and the Airport Improvement Program (AIP) are two major sources to finance U.S. airports. This paper develops a novel dynamic network DEA framework to investigate the substitutability between PFC and AIP funds. We find that the studied U.S. airports can substitute PFC for 8-35% of the current AIP funds and contribute significantly to the proposed plan of the US congress to cut AIP funding. In addition, the amount of PFC-for-AIP funds substitution negatively correlates with the productive efficiency of airports. The findings send an important message for future policy reforms on U.S. airport financing. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Supply chain coordination with a single supplier and multiple retailers considering customer arrival times and route selection

Moon, I.,Feng, X. Elsevier Science Ltd ; Pergamon ; Elsevier Science 2017 TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANS Vol.106 No.-

<P>We address a novel decentralized supply chain with one supplier and multiple independent retailers based on the practice of several supply chains in the real world. Coordination of such a supply chain has rarely been studied. Despite overcoming the well-known double marginalization, the supplier's route selection can obstruct supply chain coordination. We present a wholesale-price-and-carpooling contract to coordinate such a supply chain. We demonstrate supply chain coordination under such a contract and show that the profit along the supply chain can be arbitrarily allocated. We show that the popular revenue-sharing contract may lose flexibility in profit allocations. (C) 2017 Elsevier Ltd. All rights reserved.</P>

Warehouse capacity sharing via transshipment for an integrated two-echelon supply chain

Feng, X.,Moon, I.,Ryu, K. Elsevier Science Ltd ; Pergamon ; Elsevier Science 2017 TRANSPORTATION RESEARCH PART E-LOGISTICS AND TRANS Vol.104 No.-

<P>Warehouse capacity constraint has been one obstacle to achieving the channel-wide optimal decision in inventory management. We studied an integrated inventory model consisting of a single vendor and multiple buyers with warehouse capacity sharing via transshipment. We proposed an optimal transshipment policy by developing nonlinear programming models and genetic algorithms as well as obtaining Karush-Kuhn-Tucker points. This inventory policy can significantly reduce the channel-wide cost and the performance is influenced by the consideration of fixed transshipment costs. Sensitivity analyses show that parameters have different impacts on the channel-wide cost and the performances of the algorithms. (C) 2017 Published by Elsevier Ltd.</P>

Spatiotemporal analysis of snow cover variations at Mt. Kilimanjaro using multi-temporal Landsat images during 27 years

Park, S.H.,Lee, M.J.,Jung, H.S. Elsevier Science Ltd ; Pergamon 2016 Journal of Atmospheric and Solar-Terrestrial Physi Vol.143 No.-

<P>The Landsat TM and ETM+ images have been acquired for the long period from the 1980s until the present with the temporal resolution of a 16-day repeat cycle from the visible, near infrared (NIR), short wave infrared (SWIR) and thermal infrared (TIR) bands. The Landsat multi-temporal images have been successfully used to monitor variations of the Earth surface during 27 years. In this paper, we observe the variations of (1) the snow cover area, (2) the snowline height and (3) the land surface temperature (LST) lapse rate at Mt. Kilimanjaro using a total number of 15 Landsat-5 TM and Landsat-7 ETM+ images from June 1984 July 2011. Segmentation of normalized difference snow index (NDSI) images with a threshold of 0.6 is used to extract snow cover. Snowline altitude is then determined by combining the snow cover classification maps with a digital elevation model (DEM). And the LST lapse rate is also calculated from the TIR band in the forest area. The results from this study show that (1) the snow cover area largely decreases from 10.1 km(2) to 2.3 km(2) during about 27 years, which corresponds to a 77.2% reduction, (2) the snowline height rose from 4760 m to 5020 m by about 260 m, and (3) the LST lapse rate shifted from -5.2 degrees C/km to 2.7 degrees C/km. This study demonstrates that multi-temporal Landsat images can be successfully used for the spatiotemporal analysis of long-term snow cover changes. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Energy recovery from microalgal biomass via enhanced thermo-chemical process

Kwon, E.E.,Yi, H.,Kwon, H.H. Pergamon ; Elsevier Science Ltd 2014 Biomass & bioenergy Vol.63 No.-

<P>This work showed that microalgae having low lipid content has high potential for energy recovery via thermo-chemical processes. As an example, Microcystis aeruginosa (M. aeruginosa) was considered and tested. Specifically, this work verified that the growth rate of M. aeruginosa was extremely fast compared to other microalgae (as a factor of 10). Moreover, this work investigated the CO2 co-feed impact on thermo-chemical processes (pyrolysis/ gasification) using M. aeruginosa. Introducing CO2 in the thermo-chemical process as reaction media or feedstock can enhance the efficiency of thermo-chemical processes by expediting the cracking capability of condensable hydrocarbons (tar). The generation of CO was enhanced as a factor of similar to 2. Further generation of H-2 could be achieved in the presence of CO2. Thus, utilizing CO2 as reaction media or chemical feedstock can modify the end products into environmentally benign and desirable ones. The CO2 co-feed impact on thermo-chemical processes with lingo-cellulosic biomass can be universally applied. (C) 2014 Elsevier Ltd. All rights reserved.</P>

Impacts of air-sea exchange coefficients on snowfall events over the Korean Peninsula

Kang, J.Y.,Kwon, Y.C. Elsevier Science Ltd ; Pergamon 2016 Journal of Atmospheric and Solar-Terrestrial Physi Vol.146 No.-

<P>Snowfall over the Korean Peninsula is mainly associated with air mass transformation by the fluxes across the air-sea interface during cold-air outbreaks over the warm Yellow Sea. The heat and momentum exchange coefficients in the surface flux parameterization are key parameters of flux calculations across the air-sea interface. This study investigates the effects of the air-sea exchange coefficients on the simulations of snowfall events over the Korean Peninsula using the Weather Research and Forecasting (WRF) model. Two snowfall cases are selected for this study. One is a heavy snowfall event that took place on January 4, 2010, and the other is a light snowfall event that occurred on December 2324, 2011. Several sensitivity tests are carried out with increased and decreased heat and momentum exchange coefficients. The domain-averaged precipitation is increased (decreased) with increased (decreased) heat exchange coefficient because the increased (decreased) surface heat flux leads to more (less) moist conditions in the low level of the atmosphere. On the other hand, the domain-averaged precipitation is decreased (increased) with increased (decreased) momentum exchange coefficient because the increased (decreased) momentum coefficient causes reduction (increase) of wind speed and heat flux. The variation of precipitation in the heat exchange coefficient experiments is much larger than that in the momentum exchange coefficient experiments because the change of heat flux has a more direct impact on moisture flux and snowfall amount, while the change of momentum flux has a rather indirect impact via wind speed changes. The low-pressure system is intensified and moves toward North when the heat exchange coefficient is increased because warming and moistening of the lower atmosphere contributes to destabilize the air mass, resulting in the change of precipitation pattern over the Korean Peninsula in the heat exchange coefficient experiments. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Study of rain attenuation in Ka band for satellite communication in South Korea

Shrestha, S.,Choi, D.Y. Elsevier Science Ltd ; Pergamon 2016 Journal of Atmospheric and Solar-Terrestrial Physi Vol.148 No.-

<P>The important factor to be considered in the link budget estimation for satellite communication systems, operating at frequencies above 10 GHz is the rain attenuation. Scattering and absorption are the main concern for system designers at these frequency bands. This has resulted in the need for suitable prediction models that can best provide estimates of attenuation due to rain with available information of rain attenuation data. Researchers have developed models that can be used to estimate 1-min rainfall attenuation distribution for earth space link but there is still some confusion with regard to choosing the right model to predict attenuation for the location of interest. In this context, the existing prediction models need to be tested against the measured results. This paper presents studies on rain attenuation at 19.8 GHz, which specifies the performance parameters for Ka-Band under earth space communication system. It presents the experimental result of rain rates and rain-induced attenuation in 19.8 and 20.73 GHz for vertical and circular polarization respectively. The received signal data for rain attenuation and rain rate were collected at 10 s intervals over a three year periods from 2013 to 2015. The data highlights the impact of clear air variation and rain fade loss. Rain rate data was measured through OTT Parsivel. During the observation period, rain rates of about 50 mm/h and attenuation values of 11.6 dB for 0.01% of the time were noted. The experimental link was set up at Korea Radio Promotion Association, Mokdong, Seoul. Out of several models, this paper present discussion and comparison of ITU-R P.618-12, Unified Method, Dissanayake Allnutt and Haidara (DAH), Simple Attenuation (SAM), Crane Global and Ramachandran and Kumar models. The relative error margin of 27.51, 89.84,72.46% and 67.24, 130.84, 166.48% are obtained for 0.1%, 0.01% and 0.001% of the time for 19.8 and 20.73 GHz under vertical and circular polarization respectively from ITU-R P. 618-12 method which has been analyzed in the further section of this article. In order to obtain the better approximation of rain induced attenuation, the suitable method is proposed for earth space link whose efficiency have been compared with prominent rain attenuation models. The method provides useful information for system engineers and researchers in making a decision over the choice of suitable rain attenuation prediction method for earth space communication operating in the South Korea region. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Characterization of cell wall structure in dilute acid-pretreated biomass by confocal Raman microscopy and enzymatic hydrolysis

Na, B.I.,Chang, S.J.,Lee, K.H.,Lee, G.,Lee, J.W. Pergamon ; Elsevier Science Ltd 2016 Biomass & bioenergy Vol.93 No.-

<P>The chemical and ultrastructural properties of cell walls were investigated to determine the effect of dilute acid pretreatment on the hydrolysis of lignocellulosic biomass. Confocal Raman microscopy was used to gain a clear understanding of how dilute acid pretreatments destroy lignocellulosic cell walls. Total fermentable sugar (glucose and xylose) was high in oxalic acid hydrolysate (26.18 g/L) compared to that in sulfuric acid hydrolysate (24.34 g/L). Chemical composition of the pretreated biomass differed slightly according to the acid catalyst used. Oxalic acid pretreatment was effective for enzymatic hydrolysis, with 29.46 g/L of total fermentable sugar after 96 h. Optical microscopy showed that dilute acid pretreatment significantly changed cell wall structure, and broken and crushed cell walls could be clearly seen during pretreatment. Based on confocal Raman peak intensity, the ratio of lignin/cellulose [I(1600)/I(900)] was low for oxalic acid-pretreated biomass compared to sulfuric acid-pretreated biomass. (C) 2016 Elsevier Ltd. All rights reserved.</P>

Chlorella sorokiniana HS1, a novel freshwater green algal strain, grows and hyperaccumulates lipid droplets in seawater salinity

Kim, B.H.,Ramanan, R.,Kang, Z.,Cho, D.H.,Oh, H.M.,Kim, H.S. Pergamon ; Elsevier Science Ltd 2016 Biomass & bioenergy Vol.85 No.-

<P>Salinity is a major abiotic stress for terrestrial plants and freshwater microalgae alike. The most notable physiological response of microalgae like Dunaliella to salinity stress is reduced photosynthesis and production of carotenoids. Here, we report isolation and characterization of a novel freshwater microalgal strain, Chlorella sorokiniana HS1, which grows and hyperaccumulates lipid droplets (LD) in hypersaline conditions greater than seawater salinity. Other freshwater Chlorella strains tested neither grew nor possessed high LD levels in high salt concentration. C. sorokiniana HS1 displayed increase in cell size (200%) and LD, resulting in increased biomass and lipid productivity, respectively, with altered but favourable fatty acid methyl ester composition under salinity stress. Experimental analyses reveal definitive shift from proteins and starch to LD synthesis as well as chlorophyll degradation, response analogous to nitrogen starvation. Acute salt stress (<6 h) in seawater salinity or above resulted in instant accumulation of LD. C. sorokiniana HS1 allows for two phase cultivation, growth phase in freshwater and stress induction phase in seawater for biodiesel production. This strain would therefore significantly reduce costs and production constraints associated with stress induction. (C) 2015 Elsevier Ltd. All rights reserved.</P>

Comparing the influence of acetate and chloride anions on the structure of ionic liquid pretreated lignocellulosic biomass

Kim, H.,Ahn, Y.,Kwak, S.Y. Pergamon ; Elsevier Science Ltd 2016 Biomass & bioenergy Vol.93 No.-

<P>The effect of the anion type, in an ionic liquid, on the transition of the crystalline structure when lignocellulose was pretreated in 1-ethyl-3-methylimidazolium acetate (EmimOAC) or 1-ethyl-3-methylimidazolium chloride (EmimCl) was studied. The influence of the pretreatment on the composition, the molecular structure, and the crystalline structure was observed using Fourier-transform infrared (FT-IR) compositional analysis, thermogravimetric analysis (TGA), rheological behavior, and Xray diffraction (XRD). Compared to EmimCl, EmimOAC pretreatment substantially decreased the lignin and hemicellulose contents. The pretreatment also significantly changed the entanglement or cross-linking state of polymer chains in the lignocellulose solution. The changes in lignin content and the transformation from cellulose I to II were dependent on the anion type of the ionic liquid. The pretreated samples were recrystallized to cellulose II only in EmimOAC, whereas the samples pretreated with EmimCl had both cellulose I and II structures present at the same time. (C) 2016 Published by Elsevier Ltd.</P>