595 research outputs found

    FDD Algorithm for an AHU Reverse-Return System

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    A fault detection and diagnosis (FDD) algorithm was developed for an AHU reverse-return system for air cooling. These FDD rules were generated using simulation in three steps. Cause-effect rules were established by connecting the faults and their related effects. The FDD rules were developed for the following faults: old valve, fouled return pipe, fault in the outlet air temperature sensor, fault in the temperature sensor for the inlet temperature, bad position of the sensor for pressure difference. The effects of the involved faults were observed on four system performances. The results showed that increase in both the cooling coil rate and the pump rate appear due to faults in sensors. The inaccurate measurement of the pressure difference and the fault in the control valve do not affect the AHU outlet air temperatures. Increase in both the outlet air temperature and the pump power consumption appears due to the fouled return pipes

    Norwegian National Program for Lifetime Commissioning and Energy Efficient Operation of Buildings

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    The project β€œLife-Time Commissioning for Energy Efficient Operation of Buildings” is actually a network of industrial companies, private and public entities, and R&D organizations. The overall objective of the project is to contribute to the implementation of life-long commissioning of building HVAC systems, so that this becomes a standardized way of building, operating and maintaining the HVAC systems in Norway. The project is organized as an industry research program with minimum duration of five years. Project members pay an annual membership fee. The main goal for the project is to develop, verify, document and implement suitable tools for functional control of energy and indoor environment in buildings under continuous operation during the entire operational life of the building. This will improve energy efficiency and ensure a rational use of energy and a sound indoor environment. All achievements concerning energy improvement will also contribute to the decrease of CO2 emissions

    The Transient Jupiter Trojan-Like Orbit of P/2019 LD2 (ATLAS)

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    Comet P/2019 LD2 has orbital elements currently resembling those of a Jupiter Trojan, and therefore superficially appears to represent a unique opportunity to study the volatile content and active behavior of a member of this population for the first time. However, numerical integrations show that it was previously a Centaur before reaching its current Jupiter Trojan-like orbit in 2018 July, and is expected to return to being a Centaur in 2028 February, before eventually becoming a Jupiter-family comet in 2063 February. The case of P/2019 LD2 highlights the need for mechanisms to quickly and reliably dynamically classify small solar system bodies discovered in current and upcoming wide-field surveys.Comment: 7 pages, 3 figures. Accepted for publication in Icaru

    Experimental verification of calculated lattice relaxations around impurities in CdTe

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    We have measured the lattice distortion around As acceptor and Br donor in CdTe with fluorescence detected X ray absorption spectroscopy. We could experimentally verify the lattice relaxation with a bond length reduction of 8 around the As atom as inferred indirectly from ab initio calculations of the electric field gradient performed with the WIEN97 package in comparison with the measured value in a Perturbed Angular Correlation experiment as recently reported. We have complemented our own calculations of relaxation with WIEN97 with calculations using the FHI96md pseudo potential program which allows the use of larger super cell sizes. Encouraged by the good agreement between experiment and model calculation for As in CdTe as well as similarly for the isovalent Se in CdTe, we extended our investigation to Br in CdTe, where the electric field gradient has also been measured, and could not only verify the derived lattice expansion around Br with our EXAFS analysis but additionally observe fractions of Br in the A center as well as in a DX center configuratio

    НСкоторыС особСнности ΠΊΠΎΠ½Ρ†Π΅Π½Ρ‚Ρ€Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Ρ… ΠΊΠΎΠ»Π΅Π±Π°Π½ΠΈΠΉ Π² Ρ€Π΅Π°ΠΊΡ†ΠΈΠΈ ΠΎΠΊΠΈΡΠ»ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΠ³ΠΎ карбонилирования Ρ„Π΅Π½ΠΈΠ»Π°Ρ†Π΅Ρ‚ΠΈΠ»Π΅Π½Π°

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    Some modes of concentration oscillations in the homogeneous system KI-PdI2-CO-O2-CH3OH are described in this paper. Described modes of phenylacetylene oxidative carbonylation reaction in this system have some distinctive features. The further studies would reveal the reasons of these special modes and help one to understand in more details the mechanism of concentration oscillations of unsaturated compounds occurring in the carbonylation reactions.Π’ Π΄Π°Π½Π½ΠΎΠΉ ΡΡ‚Π°Ρ‚ΡŒΠ΅ описаны Π½Π΅ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Π΅ Ρ€Π΅ΠΆΠΈΠΌΡ‹ ΠΊΠΎΠ½Ρ†Π΅Π½Ρ‚Ρ€Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Ρ… ΠΊΠΎΠ»Π΅Π±Π°Π½ΠΈΠΉ Π² Π³ΠΎΠΌΠΎΠ³Π΅Π½Π½ΠΎΠΉ систСмС KI-PdI2-CO-O2-CH3OH. ΠžΠΏΠΈΡΡ‹Π²Π°Π΅ΠΌΡ‹Π΅ Ρ€Π΅ΠΆΠΈΠΌΡ‹ Ρ€Π΅Π°ΠΊΡ†ΠΈΠΈ ΠΎΠΊΠΈΡΠ»ΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΠ³ΠΎ карбонилирования Ρ„Π΅Π½ΠΈΠ»Π°Ρ†Π΅Ρ‚ΠΈΠ»Π΅Π½Π° Π² этой систСмС ΠΈΠΌΠ΅ΡŽΡ‚ Π½Π΅ΠΊΠΎΡ‚ΠΎΡ€Ρ‹Π΅ Ρ…Π°Ρ€Π°ΠΊΡ‚Π΅Ρ€Π½Ρ‹Π΅ особСнности. Π”Π°Π»ΡŒΠ½Π΅ΠΉΡˆΠΈΠ΅ исслСдования Π΄ΠΎΠ»ΠΆΠ½Ρ‹ Π²Ρ‹ΡΠ²ΠΈΡ‚ΡŒ ΠΏΡ€ΠΈΡ‡ΠΈΠ½Ρ‹ возникновСния этих особых Ρ€Π΅ΠΆΠΈΠΌΠΎΠ², Π° Ρ‚Π°ΠΊΠΆΠ΅ ΠΏΠΎΠΌΠΎΡ‡ΡŒ Π³Π»ΡƒΠ±ΠΆΠ΅ ΠΏΠΎΠ½ΡΡ‚ΡŒ ΠΌΠ΅Ρ…Π°Π½ΠΈΠ·ΠΌ возникновСния ΠΊΠΎΠ½Ρ†Π΅Π½Ρ‚Ρ€Π°Ρ†ΠΈΠΎΠ½Π½Ρ‹Ρ… ΠΊΠΎΠ»Π΅Π±Π°Π½ΠΈΠΉ Π² рСакциях карбонилирования Π½Π΅ΠΏΡ€Π΅Π΄Π΅Π»ΡŒΠ½Ρ‹Ρ… соСдинСний

    Cost Optimization of Ice Distribution

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    Two questions regarding minimizing fuel costs while delivering ice along a pre-set route are tackled. The first question is when demand exceeds the load of a single truck, so that a second truck of ice has to be taken to some point of the route for the driver/salesman to continue with that for the rest of the route: Is it better: 1) for the first truck to deliver starting from the costumer nearest to the base, or 2) for the first truck to start the delivery from the last costumer (the most distant from the base)? We show that the second strategy was better for the particular data looked at, and we have the basis of an algorithm for deciding which strategy is the better for a given delivery schedule. The second question concerns how best to modify a regular sales route when an extra delivery has to be made. Again, the basis for an algorithm to decide how to minimize fuel costs is derived
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