Capacity allocation in vertically integrated rail systems: A bargaining approach

This paper presents a game-theoretic bargaining approach to allocating rail line capacity in vertically integrated systems. A passenger rail agency negotiates with the host freight railroad to determine train schedules and the associated payment. The objective on the passenger side is to maximize utility, i.e., revenue minus costs of passenger train operations, passenger schedule delay and en-route delay; the freight side minimizes the costs of train departure delay, en-route delay, loss of demand, and track maintenance. Bargaining in both complete and incomplete information settings are considered; the latter arises because the freight railroad may withhold its private cost information. With complete information, the authors find that the equilibrium payments proposed by the passenger rail agency and the host freight railroad will each be invariant to who initiates the payment bargaining, although the actual payment does depend on who is the initiator. The equilibrium schedule maximizes system welfare. With incomplete information, the passenger rail agency may choose between pooling and separating equilibrium strategies while proposing a payment, depending on its prior belief about the cost type of the freight railroad; whereas the host freight railroad will adopt strategies that do not reveal its cost type. To identify equilibrium schedules, a pooling equilibrium is constructed along with conditions for the existence of equilibrium schedules. The authors further conduct numerical experiments to obtain additional policy-relevant insights

Assessing the impacts of state-supported rail services on local population and employment: A California case study

The State of California has been financially supporting Amtrak intercity passenger rail services since 1976. This paper studies the impacts of this support on local population and employment at both county and city levels. We use datasets which include geographic, transportation, and socioeconomic characteristics of California counties and cities from 1950 to 2010. Propensity score, one-to-one matching models are employed to draw units from the control group, which are counties/cities that do not have a state-supported Amtrak station, to match with units from the treatment group, which are counties/cities that do. Using regression analysis, we find that state-support Amtrak stations have significant effect on local population in the long term, and the effect increases with time. However, the effect on civilian employment is almost non-existent. This suggests that state-supported Amtrak services can provide quality rail mobility and accessibility, which attract people to live in a rail-accessible region. However, the economic influence seems limited

Large Negative Linear Compressibility in InH(BDC)₂ from Framework Hinging

Materials with negative linear compressibility (NLC) counterintuitively expand along one specific direction coupled to the volume reduction when compressed uniformly. NLC with a large value is desired for compression and materials science. However, NLC is generally smaller than −20 TPa^–1. High-pressure X-ray diffraction experiments reveal that the β-quartz-like InH­(BDC)₂ generates an extreme NLC (−62.4 TPa^–1) by framework hinging. InH­(BDC)₂ is much safer and lower-cost than Au⁺/Ag⁺ and CN^–-containing materials that dominated the fields of large NLC. This work reconfirms that a negative thermal expansion flexible framework could likely exhibit large NLC. Moreover, a large NLC could be anticipated to arise from β-quartz-like or related frameworks composed of rigid linear ligands and flexible framework angles

Near Zero Area Compressibility in a Perovskite-Like Metal–Organic Frameworks [C(NH₂)₃][Cd(HCOO)₃]

Materials with zero area compressibility (ZAC) can keep their crystal uncompressed in two specific directions upon uniform compression. High-pressure angle-dispersive X-ray powder diffraction (ADXRD) experiments reveal a ZAC phenomenon in the <i>ab</i>-plane in crystal of a formate-based perovskite, [C­(NH₂)₃]­[Cd­(HCOO)₃]. The ZAC behavior is ascribed to the unique rhombohedral [Cd­(HCOO)₃]⁻ frameworks and confirmed by density functional theory (DFT) calculations. For the first time, a near ZAC single material is explicitly reported. This study opens up an exciting research field on pressure-resistant materials. We anticipate more ZAC materials to be discovered in the following explorations under the inspiration of this work

Pressure-Induced Structural and Optical Properties of Organometal Halide Perovskite-Based Formamidinium Lead Bromide

Organometal halide perovskites (OMHPs) are attracting an ever-growing scientific interest as photovoltaic materials with moderate cost and compelling properties. In this Letter, pressure-induced optical and structural changes of OMHP-based formamidinium lead bromide (FAPbBr₃) were systematically investigated. We studied the pressure dependence of optical absorption and photoluminescence, both of which showed piezochromism. Synchrotron X-ray diffraction indicated that FAPbBr₃ underwent two phase transitions and subsequent amorphization, leading directly to the bandgap evolution with redshift followed by blueshift during compression. Raman experiments illustrated the high pressure behavior of organic cation and the surrounding inorganic octahedra. Additionally, the effect of cation size and the different intermolecular interactions between organic cation and inorganic octahedra result in the fact that FAPbBr₃ is less compressible than the reported methylammonium lead bromide (MAPbBr₃). High pressure studies of the structural evolution and optical properties of OMHPs provide important clues in optimizing photovoltaic performance and help to design novel OMHPs with higher stimuli-resistant ability

Emission Control under Private Port Operator Duopoly

Recent trends in regulating maritime vessel emissions have negative effects on the competitiveness of many ports as regulations increase costs for shipping operators calling the ports. This paper develops analytical models to examine the emission standards set by governments for ports in their jurisdictions. Given the emission standards set by governments, which affects fuel cost experienced by shipping operators, ports determine charges for shipping operators. Unilateral, bilateral, and single-country regulation cases are investigated. Specifically, our analysis focuses on how increase in the maximum reservation price of shipping operators, port capacity, and environmental damage costs of ports affect optimal emission standards

High Pressure Structural Investigation of Benzoic Acid: Raman Spectroscopy and X‑ray Diffraction

The structural stability of benzoic acid (C₆H₅COOH, BA), a hydrogen-bonded molecular crystal, has been investigated by Raman spectroscopy and angle-dispersive X-ray diffraction (ADXRD) up to ∼18 GPa at room temperature. Under ambient conditions, benzoic acid molecules are arranged in two sets of parallel planes and held together by hydrogen bonding and van der Waals interactions. Small changes (e.g., emergence of new peaks, splitting of original peaks) can be observed in the Raman spectra at high pressures. However, no obvious changes can be observed in the X-ray diffraction measurements, which rules out any symmetry/structure changes within this pressure range. The pressure dependence of lattice parameters is presented, which shows monotonously decrease without any anomalies. The experimental isothermal pressure–volume data are well fitted by the third-order Birch–Murnaghan equation of state, yielding bulk modulus <i>B</i>₀ = 41.7(6) GPa and a first pressure derivative <i>B</i>₀^′ = 4.5(4). Axial compressibility shows obvious anisotropy, the <i>a</i> axis is more compressible than <i>b</i> and <i>c</i> axes. Moreover, the near symmetrization limit of hydrogen bonds at high pressures is proposed from the first-principles calculations. Based on the Raman, XRD, and the first-principles calculations analysis, we propose that the high pressure structural stability of benzoic acid is associated with the special hydrogen-bonded dimer structure

Pressure-Induced Structural Evolution and Optical Properties of Metal-Halide Perovskite CsPbCl₃

Metal-halide perovskites have emerged as the most promising semiconductor materials for advanced photovoltaic and optoelectronic applications. Herein, we comprehensively investigate the optical response and structural evolution of metal-halide perovskite CsPbCl₃ (ABX₃) upon compression. Band gap realized a pronounced narrowing under mild pressure followed by a sharp increase, which could be ascribed to Pb–Cl bond contraction and inorganic framework distortion, respectively. The transformation of the crystal structure is confirmed and analyzed through in situ high-pressure X-ray diffraction and Raman experiments, consistent with the evolution of optical properties. Combining with the first-principles calculations, we understand the electronic band structure changes and phase transition mechanism, which are ascribed to severe PbCl₆ octahedral titling and twisting. Our results demonstrate that the high-pressure technique can be used as a practical tool to modify the optical properties of metal-halide perovskites and maps an innovative strategy for better photovoltaic and optoelectronic device design

High-Pressure-Induced Planarity of the Molecular Arrangement in Maleic Anhydride

Maleic anhydride, an industrially important chemical, was investigated by conducting in situ high-pressure Raman scattering and synchrotron angle-dispersive X-ray diffraction (ADXRD) experiments at a pressure of up to 1.0 GPa. Drastic discontinuities of Raman modes at 0.5 GPa indicated that a phase transition occurred when pressure was elevated. This transformation is further discussed by analysis of the ADXRD results. The Raman spectra and X-ray diffraction patterns of the recovered samples indicated that this pressure-induced transformation is reversible. The calculated results by the first-principle method indicated that the pressure-induced planarity of molecular arrangement is the mechanism of this transition. This study shows that the pressure-induced phase transition of maleic anhydride at 0.5 GPa is derived from supramolecular rearrangements

Pressure-Induced Phase Transition of Hydrogen Storage Material Hydrazine Bisborane: Evolution of Dihydrogen Bonds

We report the high-pressure behavior of dihydrogen-bonded hydrogen storage material hydrazine bisborane (BH₃N₂H₄BH₃, HBB) via in situ angle-dispersive X-ray diffraction (ADXRD) and Raman spectroscopy in a diamond anvil cell up to 2.0 GPa. A reversible phase transition at 0.4 GPa was confirmed by ADXRD experiments. The Rietveld refinement showed the high-pressure phase was consistent with the crystal structure of α′-phase (low-temperature phase). Through the analysis of structure changes, Raman spectroscopy, and the Hirshfeld surface, we studied the evolution of dihydrogen bonds under high pressure and attributed the pressure-induced phase transition to the distortion and rotation of the NH₂–NH₂ group. This work will further the understanding of the characteristics of dihydrogen bonds and provide some contribution to future hydrogen storage applications of HBB