CCSD(T) Study of CD3-O-CD3 and CH3-O-CD3 Far-Infrared Spectra

From a vibrationally corrected 3D potential energy surface determined with highly correlated ab initio calculations (CCSD(T)), the lowest vibrational energies of two dimethyl-ether isotopologues, 12CH3–16O–12CD3 (DME-d3) and 12CD3–16O–12CD3 (DME-d6), are computed variationally. The levels that can be populated at very low temperatures correspond to the COC-bending and the two methyl torsional modes. Molecular symmetry groups are used for the classification of levels and torsional splittings. DME-d6 belongs to the G36 group, as the most abundant isotopologue 12CH3–16O–12CH3 (DME-h6), while DME-d3 is a G18 species. Previous assignments of experimental Raman and far-infrared spectra are discussed from an effective Hamiltonian obtained after refining the ab initio parameters. Because a good agreement between calculated and experimental transition frequencies is reached, new assignments are proposed for various combination bands corresponding to the two deuterated isotopologues and for the 020 → 030 transition of DME-d6. Vibrationally corrected potential energy barriers, structural parameters, and anharmonic spectroscopic parameters are provided. For the 3N – 9 neglected vibrational modes, harmonic and anharmonic fundamental frequencies are obtained using second-order perturbation theory by means of CCSD and MP2 force fields. Fermi resonances between the COC-bending and the torsional modes modify DME-d3 intensities and the band positions of the torsional overtones

Analysing the impact of climate change on hydrological ecosystem services in laguna del sauce (Uruguay) using the swat model and remote sensing data

Assessing how climate change will affect hydrological ecosystem services (HES) provision is necessary for long-term planning and requires local comprehensive climate information. In this study, we used SWAT to evaluate the impacts on four HES, natural hazard protection, erosion control regulation and water supply and flow regulation for the Laguna del Sauce catchment in Uruguay. We used downscaled CMIP-5 global climate models for Representative Concentration Pathways (RCP) 2.6, 4.5 and 8.5 projections. We calibrated and validated our SWAT model for the periods 2005 2009 and 2010 2013 based on remote sensed ET data. Monthly NSE and R2 values for calibration and validation were 0.74, 0.64 and 0.79, 0.84, respectively. Our results suggest that climate change will likely negatively affect the water resources of the Laguna del Sauce catchment, especially in the RCP 8.5 scenario. In all RCP scenarios, the catchment is likely to experience a wetting trend, higher temperatures, seasonality shifts and an increase in extreme precipitation events, particularly in frequency and magnitude. This will likely affect water quality provision through runoff and sediment yield inputs, reducing the erosion control HES and likely aggravating eutrophication. Although the amount of water will increase, changes to the hydrological cycle might jeopardize the stability of freshwater supplies and HES on which many people in the south-eastern region of Uruguay depend. Despite streamflow monitoring capacities need to be enhanced to reduce the uncertainty of model results, our findings provide valuable insights for water resources planning in the study area. Hence, water management and monitoring capacities need to be enhanced to reduce the potential negative climate change impacts on HES. The methodological approach presented here, based on satellite ET data can be replicated and adapted to any other place in the world since we employed open-access software and remote sensing data for all the phases of hydrological modelling and HES provision assessment. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.This work has received funding from the European Union’s Horizon 2020 research and innovation programme within the framework of the project SMARTLAGOON under grant agreement No. 101017861. This study was also supported by the State Research Agency of Spain through the excellence certification María de Maeztu (Ref. MDM-2017-0714). Celina Aznarez was supported by the Doctoral INPhINIT–INCOMING program, fellowship code (LCF/BQ/DI20/11780004), from “la Caixa” Foundation (ID 100010434). Javier Senent-Aparicio was supported by the training grant (21201/EE/19) awarded by the Séneca Foundation in the framework of the Jimenez de la Espada Mobility, Cooperation and Internationalization Program. Adrián López-Ballesteros was supported by the Spanish Ministerio de Educación, Cultura y Deporte with an FPU grant (FPU17/00923). Juan Pablo Pacheco was supported by the Sino-Danish Center–Aarhus University, the University of the Chinese Academy of Sciences and the University of the Republic, Uruguay. This work has received funding from the European Union?s Horizon 2020 research and innovation programme within the framework of the project SMARTLAGOON under grant agreement No. 101017861. This study was also supported by the State Research Agency of Spain through the excellence certification Mar?a de Maeztu (Ref. MDM-2017-0714). Celina Aznarez was supported by the Doctoral INPhINIT?INCOMING program, fellowship code (LCF/BQ/DI20/11780004), from ?la Caixa? Foundation (ID 100010434). Javier Senent-Aparicio was supported by the training grant (21201/EE/19) awarded by the S?neca Foundation in the framework of the Jimenez de la Espada Mobility, Cooperation and Internationalization Program. Adri?n L?pez-Ballesteros was supported by the Spanish Ministerio de Educaci?n, Cultura y Deporte with an FPU grant (FPU17/00923). Juan Pablo Pacheco was supported by the Sino-Danish Center?Aarhus University, the University of the Chinese Academy of Sciences and the University of the Republic, Uruguay. The authors acknowledge Paper Check Proofreading and Editing Services for proofreading the manuscript

A new ab initio potential energy surface for the collisional excitation of N2H(+) by H2

10 pags.; 14 figs.© 2015 AIP Publishing LLC. We compute a new potential energy surface (PES) for the study of the inelastic collisions between N2H+ and H2 molecules. A preliminary study of the reactivity of N2H+ with H2 shows that neglecting reactive channels in collisional excitation studies is certainly valid at low temperatures. The four dimensional (4D) N2H+–H2 PES is obtained from electronic structure calculations using the coupled cluster with single, double, and perturbative triple excitation level of theory. The atoms are described by the augmented correlation consistent triple zeta basis set. Both molecules were treated as rigid rotors. The potential energy surface exhibits a well depth of ≃2530 cm−1. Considering this very deep well, it appears that converged scattering calculations that take into account the rotational structure of both N2H+ and H2 should be very difficult to carry out. To overcome this difficulty, the “adiabatic-hindered-rotor” treatment, which allows para-H2(j = 0) to be treated as if it were spherical, was used in order to reduce the scattering calculations to a 2D problem. The validity of this approach is checked and we find that cross sections and rate coefficients computed from the adiabatic reduced surface are in very good agreement with the full 4D calculationsThis research was supported by the CNRS national program “Physique et Chimie du Milieu Interstellaire.” F.L. and Y.K. also thank the Agence Nationale de la Recherche (ANR-HYDRIDES), contract No. ANR-12-BS05-0011-01. We acknowledge Laurent Pagani for stimulating this work.Peer Reviewe

An analysis of the methyl rotation dynamics in the S0 (X̃ 1A1) and T1 (ã 3A2) states of thioacetone, (CH3)2 CS and (CD 3)2 CS from pyrolysis jet spectra

Jet-cooled, laser-induced phosphorescence excitation spectra (LIP) of thioacetone (CH3)2CS/(CD3)2 CS have been recorded over the region 16 800-18 500 cm-1 using the pyrolysis jet spectroscopic technique. The responsible electronic transition, T 1 ←-S0, ã 3 A ″ ← X̃ 1A1, results from an n → π* electron promotion and gives rise to a pattern of vibronic bands that were attributed to activity of the methyl torsion and the sulphur out-of-plane wagging modes. The intensities of the torsional and wagging progressions in the excitation spectra were interpreted in terms of a C2υ-Cs molecular distortion of the triplet molecule from its singlet ground state equilibrium structure. A complete unrestricted Hartree-Fock (UHF) ab initio molecular orbital (MO) structural optimization of the T1 state predicted that the sulphur was displaced by 27.36° from the molecular plane and the methyl groups were rotated by 10.93° in clockwise-counterclockwise directions. Restricted Hartree-Fock (RHF) calculations were used to generate the F(θ1,θ2) potential surface governing methyl rotation for the S0 state. This was incorporated into a two-dimensional Hamiltonian, symmetrized for the G36 point group and solved variationally for the torsional frequencies. The calculated frequencies of 159.97/118.94 for the ν17 (b1) mode of S0 (CH3)2CS/(CD3)2 CS were found to agree with the experimental values, 153.2/114.7 cm-1. © 1991 American Institute of Physics.The authors are grateful to the Natural Sciences and Engineering Research Council of Canada for financial support of this work. D. J. C. acknowledges the support of the National Science Foundation through Grant No. CHE-8914403.Peer Reviewe

The Mission Assessment Post Processor (MAPP): A New Tool for Performance Evaluation of Human Lunar Missions

The National Aeronautics and Space Administration s (NASA) Constellation Program paves the way for a series of lunar missions leading to a sustained human presence on the Moon. The proposed mission design includes an Earth Departure Stage (EDS), a Crew Exploration Vehicle (Orion) and a lunar lander (Altair) which support the transfer to and from the lunar surface. This report addresses the design, development and implementation of a new mission scan tool called the Mission Assessment Post Processor (MAPP) and its use to provide insight into the integrated (i.e., EDS, Orion, and Altair based) mission cost as a function of various mission parameters and constraints. The Constellation architecture calls for semiannual launches to the Moon and will support a number of missions, beginning with 7-day sortie missions, culminating in a lunar outpost at a specified location. The operational lifetime of the Constellation Program can cover a period of decades over which the Earth-Moon geometry (particularly, the lunar inclination) will go through a complete cycle (i.e., the lunar nodal cycle lasting 18.6 years). This geometry variation, along with other parameters such as flight time, landing site location, and mission related constraints, affect the outbound (Earth to Moon) and inbound (Moon to Earth) translational performance cost. The mission designer must determine the ability of the vehicles to perform lunar missions as a function of this complex set of interdependent parameters. Trade-offs among these parameters provide essential insights for properly assessing the ability of a mission architecture to meet desired goals and objectives. These trades also aid in determining the overall usable propellant required for supporting nominal and off-nominal missions over the entire operational lifetime of the program, thus they support vehicle sizing

Numerical Simulation of the Flow Inside a Scroll Compressor Equipped with Intermediate Discharge Valves

This paper presents the results of CFD simulations of the compression process of a scroll compressor. The compressor geometry accounts for the final scroll gas pockets, two Intermediate Discharge Valves (IDVs), the central discharge zone and the upper shell. The numerical model uses a real gas equation of state to determine gas properties during the compression process and accounts for the motion of the orbiting scroll and IDVs using a mesh smoothing and remeshing algorithm. The IDVs are represented as a spring mass system with their movement controlled via the pressure difference around the valve. Appropriate pressure based boundary conditions are used at entry to the third gas pocket and at the exit of the upper shell. An initial analysis of the results has shown that it is possible to achieve time accurate results of the pressure field throughout the flow domain and also determine the impact of the IDVs on scroll performance. The results will also enable a more thorough analysis of the fluid flow and compression process inside the scroll in order to improve its performance

La construcción de la bóveda de arista rectangular en el tratado de Gelabert: teoría y práctica

The groin vault is one of the most common types of vaults in Spain, designed to cover square spaces. When the groin vault is arranged on a rectangular plan, the vaulting system must be adapted to the new situation. This new arrangement multiplies the problems, entailing in different constructive solutions. This paper analyzes the theoretical model of the rectangular groin vault as proposed in stonecutting treatises (16th-18th centuries), focusing on the manuscript by Joseph Gelabert (17th century), and its relationship with vaults built in Palma de Mallorca from the 16th to the 18th century. Special attention is paid to the carving of the pieces of the groins by means of templates and their relationship to the “problem of the solid angle”, providing new data on a drawing in the manuscript of Hernán Ruiz the Younger (16th century).Entre los tipos de bóvedas más habituales del renacimiento español está la bóveda de arista, concebida para cubrir recintos cuadrados. Cuando la bóveda de arista se dispone sobre una planta rectangular, es necesario que el sistema de abovedamiento se adapte a esta nueva situación, lo que multiplica los problemas, dando lugar a diversas soluciones constructivas. Este artículo analiza el modelo teórico de bóveda de arista rectangular propuesto por los tratados de cantería de los siglos XVI-XVIII, centrándose en el manuscrito del mallorquín Joseph Gelabert (s. XVII), y su relación con bóvedas de este tipo construidas en la ciudad de Palma de Mallorca entre los siglos XVIXVIII. Se presta especial atención al problema de la labra de las dovelas de la arista por medio de plantillas y su relación con el “problema del ángulo sólido”, aportando nuevos datos sobre un dibujo del manuscrito de Hernán Ruiz el Joven (s. XVI)

Patients' satisfaction with community treatment: a pilot cross-sectional survey adopting multiple perspectives.

ACCESSIBLE SUMMARY: Patients' satisfaction is scarcely studied within the context of community treatment for adolescents. Thus, this study adopts a multiple perspective on patients' satisfaction (including service users as well as staff members). The results highlighted that all informants (patients, foster carers in foster homes and professional caregivers from community treatment teams) perceived the patients to be satisfied, with foster carers reporting the highest patient satisfaction rate. Considering the patient satisfaction rate from multiple perspectives provides complementary understandings. Clinical outcomes and, specifically, a reduction in emotional difficulties were related to patient's satisfaction, but only from the patients' perspective. ABSTRACT: Community treatment (CT) teams in Switzerland provide care to patients who are unable to use regular child and adolescent mental health services (i.e. inpatient and outpatients facilities). No study has considered patients' self-rated satisfaction alongside with staff members' perspectives on patient satisfaction. Thus, adopting a cross-sectional survey design, we collected patients' satisfaction using the Client Satisfaction Questionnaire (CSQ-8), rated by multiple informants (patients, foster carers in foster homes and professional caregivers from CT teams). Professional caregivers assessed clinical outcomes using the Health of the Nation Outcome Scale for Children and Adolescents. The results indicated that all informants were satisfied with the community treatment teams. The satisfaction scores were not correlated across informants; however, the alleviation of emotional symptoms was correlated with patients' satisfaction. This study indicated that the use of a combined approach including the views of service users and professionals gives important complementary information. Finally, in our sample, lower emotional symptoms were linked to enhanced patient satisfaction. This study demonstrated the importance of considering multiple perspectives to obtain the most accurate picture of patients' satisfaction. Second, focusing on the reduction of emotional symptoms might lead to a higher degree of patients' satisfaction

Laboratory and tentative interstellar detection of trans-methyl formate using the publicly available Green Bank Telescope PRIMOS survey

The rotational spectrum of the higher-energy trans conformational isomer of methyl formate has been assigned for the first time using several pulsed-jet Fourier transform microwave spectrometers in the 6-60 GHz frequency range. This species has also been sought toward the Sagittarius B2(N) molecular cloud using the publicly available PRIMOS survey from the Green Bank Telescope. We detect seven absorption features in the survey that coincide with laboratory transitions of trans-methyl formate, from which we derive a column density of 3.1 (+2.6, -1.2) \times 10^13 cm-2 and a rotational temperature of 7.6 \pm 1.5 K. This excitation temperature is significantly lower than that of the more stable cis conformer in the same source but is consistent with that of other complex molecular species recently detected in Sgr B2(N). The difference in the rotational temperatures of the two conformers suggests that they have different spatial distributions in this source. As the abundance of trans-methyl formate is far higher than would be expected if the cis and trans conformers are in thermodynamic equilibrium, processes that could preferentially form trans-methyl formate in this region are discussed. We also discuss measurements that could be performed to make this detection more certain. This manuscript demonstrates how publicly available broadband radio astronomical surveys of chemically rich molecular clouds can be used in conjunction with laboratory rotational spectroscopy to search for new molecules in the interstellar medium.Comment: 40 pages, 7 figures, 4 tables; accepted for publication in Ap

Natural and sail-displaced doubly-symmetric Lagrange point orbits for polar coverage

This paper proposes the use of doubly-symmetric, eight-shaped orbits in the circular restricted three-body problem for continuous coverage of the high-latitude regions of the Earth. These orbits, for a range of amplitudes, spend a large fraction of their period above either pole of the Earth. It is shown that they complement Sun-synchronous polar and highly eccentric Molniya orbits, and present a possible alternative to low thrust pole-sitter orbits. Both natural and solar-sail displaced orbits are considered. Continuation methods are described and used to generate families of these orbits. Starting from ballistic orbits, other families are created either by increasing the sail lightness number, varying the period or changing the sail attitude. Some representative orbits are then chosen to demonstrate the visibility of high-latitude regions throughout the year. A stability analysis is also performed, revealing that the orbits are unstable: it is found that for particular orbits, a solar sail can reduce their instability. A preliminary design of a linear quadratic regulator is presented as a solution to stabilize the system by using the solar sail only. Finally, invariant manifolds are exploited to identify orbits that present the opportunity of a ballistic transfer directly from low Earth orbit