Vacuum-UV spectroscopy of interstellar ice analogs. II. Absorption cross-sections of nonpolar ice molecules

Dust grains in cold circumstellar regions and dark-cloud interiors at 10-20 K are covered by ice mantles. A nonthermal desorption mechanism is invoked to explain the presence of gas-phase molecules in these environments, such as the photodesorption induced by irradiation of ice due to secondary ultraviolet photons. To quantify the effects of ice photoprocessing, an estimate of the photon absorption in ice mantles is required. In a recent work, we reported the vacuum-ultraviolet (VUV) absorption cross sections of nonpolar molecules in the solid phase. The aim was to estimate the VUV-absorption cross sections of nonpolar molecular ice components, including CH4, CO2, N2, and O2. The column densities of the ice samples deposited at 8 K were measured in situ by infrared spectroscopy in transmittance. VUV spectra of the ice samples were collected in the 120-160 nm (10.33-7.74 eV) range using a commercial microwave-discharged hydrogen flow lamp. We found that, as expected, solid N2 has the lowest VUV-absorption cross section, which about three orders of magnitude lower than that of other species such as O2, which is also homonuclear. Methane (CH4) ice presents a high absorption near Ly-alpha (121.6 nm) and does not absorb below 148 nm. Estimating the ice absorption cross sections is essential for models of ice photoprocessing and allows estimating the ice photodesorption rates as the number of photodesorbed molecules per absorbed photon in the ice.Comment: 9 pages, 6 figures, 7 table

A modified leapfrog scheme for shallow water equations

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Computers & Fluids 52 (2011): 69-72, doi:10.1016/j.compfluid.2011.08.019.In the 1D linearized shallow water equations, the Courant number should be < 0.5 for stability in the original Leapfrog (LF) scheme. Here, we propose using the time-averaged heights in the pressure gradient force in the momentum equations. The stability analysis shows that the new scheme is neutral when Courant number <1. The scheme is 2nd order accurate in both time and space. It does not require iterations and can be easily applied in 2D or 3D wave equations. The numerical simulations for 2-D linearized shallow water equations are consistent with those obtained from a 2-time-step semi-implicit scheme

Causes of delays in the construction phase of Chinese building projects

Purpose: Delays during construction are one of the common scenarios in the construction industry. The purpose of this paper is to identify the primary causes of delays in the construction phase of building construction projects in China. Design/methodology/approach: Questionnaire survey approach was adopted across the four typical cities in China, namely, Beijing, Shanghai, Chongqing and Shenzhen. In total, 115 sets of valid responded questionnaires were collected and analyzed. Findings: The results show that the causes of variations, delays in progress payments, exceptionally low bids and subcontractors’ poor performance and communication issues were the most important causes of delays in China. Originality/value: This research is the first questionnaire survey on the causes of delays in the construction phase of building construction projects in China. The comparative analysis shows two unique causes of delays in the Chinese construction industry, such as “difficulty in claiming indemnity” and “unreasonable upfront capital demanded by client.” It also reveals different ranked causes of delays as per distinguished political and economic situations in China. The research findings can be referred by construction projects in other countries that are funded or partnered with China

A Bibliometric Review on Risk Management and Building Information Modeling for International Construction

International construction is complicated and involves high risks. However, with the development of technological innovation, Building Information Modeling (BIM) emerged and seems to be able to address certain risks. To understand BIM applications in risk management for international construction, a state-of-the-art review is required. Therefore, this paper aims to identify the research trends and opportunities for risk management in BIM-enabled international construction by reviewing 526 peer-reviewed journal articles for the years 2007-2017. Thus five steps of bibliometric analysis were conducted based on the proposed frameworks of BIM risk management in international construction (BIM-RM-INTL). The results show that the popularization of BIM not only attracts all stakeholders' interests but also brings some risks. For example, financial factors are hard to detect and control through BIM, information loss during transmission stands out, and BIM has no unified standards and regulations for international construction. The research has mapped existing research results and their relationships for future risk management in BIM-enabled international construction

Larkin-Ovchinnikov-Fulde-Ferrell phase in the superconductor (TMTSF)2ClO4: Theory versus experiment

We consider a formation of the Larkin-Ovchinnikov-Fulde-Ferrell (LOFF) phase in a quasi-one-dimensional (Q1D) conductor in a magnetic field, parallel to its conducting chains, where we take into account both the paramagnetic spin-splitting and orbital destructive effects against superconductivity. We show that, due to a relative weakness of the orbital effects in a Q1D case, the LOFF phase appears in (TMTSF)$_2$ClO$_4$ superconductor for real values of its Q1D band parameters. We compare our theoretical calculations with the recent experimental data by Y. Maeno's group [S. Yonezawa et al., Phys. Rev. Lett. \textbf{100}, 117002 (2008)] and show that there is a good qualitative and quantitative agreement between the theory and experimental data.Comment: 4 pages, 1 figur

Router Agent Technology for Policy-Based Network Management

This innovation can be run as a standalone network application on any computer in a networked environment. This design can be configured to control one or more routers (one instance per router), and can also be configured to listen to a policy server over the network to receive new policies based on the policy- based network management technology. The Router Agent Technology transforms the received policies into suitable Access Control List syntax for the routers it is configured to control. It commits the newly generated access control lists to the routers and provides feedback regarding any errors that were faced. The innovation also automatically generates a time-stamped log file regarding all updates to the router it is configured to control. This technology, once installed on a local network computer and started, is autonomous because it has the capability to keep listening to new policies from the policy server, transforming those policies to router-compliant access lists, and committing those access lists to a specified interface on the specified router on the network with any error feedback regarding commitment process. The stand-alone application is named RouterAgent and is currently realized as a fully functional (version 1) implementation for the Windows operating system and for CISCO routers

IMECE2002-32487 AN ANTHROPOMETRIC ARM FOR THE HUMANOID ROBOT: DESIGN AND ANALYSIS OF THE TYCHE-ARM

Abstract: This paper is concerned with the development of an anthropometric robot arm for the humanoid robotTyche. The design was based on physiology and anthropometry of the human arm. The Tyche-arm uses a skew-pantograph mechanism, as the control device, that helps in magnifying the input. The link lengths of the structure are determined based on topological studies and avoidance of the singularity condition. A fault tolerant design for the linear actuator is incorporated in the design. The kinematic and dynamic analyses of the Tyche-arm are performed on the weight lifting activity, with the upper arm fixed in five different positions. The kinematic parameters, axial forces in the links and the torques for each joint are obtained and plotted with respect to time

Iterative Design and Usability Testing of the iMHere System for Managing Chronic Conditions and Disability

A novel mobile health platform, Interactive Mobile Health and Rehabilitation (iMHere), is being developed to support wellness and self-management among people with chronic disabilities. The iMHere system currently includes a smartphone app with six modules for use by persons with disabilities and a web portal for use by medical and rehabilitation professionals or other support personnel. Our initial clinical research applying use of this system provides insight into the feasibility of employing iMHere in the development of self-management skills in young adults (ages 18-40 years) with spina bifida (Dicianno, Fairman, McCue, Parmanto, Yih, et al., 2015). This article is focused on describing the iterative design of the iMHere system including usability testing of both the app modules and clinician portal. Our pilot population of persons with spina bifida fostered the creation of a system appropriate for people with a wide variety of functional abilities and needs. As a result, the system is appropriate for use by persons with various disabilities and chronic conditions, not only spina bifida. In addition, the diversity of professionals and support personnel involved in the care of persons with spina bifida (SB) also enabled the design and implementation of the iMHere system to meet the needs of an interdisciplinary team of providers who treat various conditions. The iMHere system has the potential to foster communication and collaboration among members of an interdisciplinary healthcare team, including individuals with chronic conditions and disabilities, for client-centered approach to support self-management skills.