Research on the Efficiency and Economic Impact of Energy-Saving Transformation of Residential Buildings in Different Climatic Regions of China

In China, the transformation of existing buildings is confronted with various problems in aspects ranging from technology to policy and even to economic efficiency, which restrains the pace of existing building transformation. Aiming at these conditions, a building model is established with simulation software in the research herein to deeply analyze the energy-saving effect of building envelope transformation in different climatic regions and its economic efficiency based on regional and national policies. The research results show that any single technology is difficult to completely satisfy the requirements of current energy efficiency standards, and technical measures should be taken according to different climatic regions. For the northern heating area, the building envelope transformation must be carried out simultaneously with the transformation of heat metering. Policy formulation and fund determination for the energy-saving transformation of existing buildings in China should be more flexible based on transformation effect and rely more on social and commercial forces rather than solely on the promotion of government

A novel method to enhance the sensitivity for two-degrees-of-freedom straightness measurement

A low cost and high precision system which can measure two-degrees-of-freedom straightness simultaneously is proposed based on a laser collimator. In the system, a miniature fiber coupled diode laser generates a collimating beam. The sensitivity of the straightness error measurement is magnified by a factor of 4 compared with the lateral movement of the retro-reflector itself after the multi-reflections. A Renishaw ML10 laser interference measurement system was used to verify the developed system in a series of experiments in the laboratory environment. Experimental results agree with the expected results. The two-dimensional straightness error measurement had linear correlativity close to 1 and the standard one-to-one deviation error was better than 0.32 µm obtained over a travel range of 600 µm.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58131/2/mst7_12_014.pd

Long-Term Stable Online Acetylene Detection by a CEAS System with Suppression of Cavity Length Drift

A trace acetylene (C2H2) detection system was demonstrated using the cavity-enhanced absorption spectroscopy (CEAS) technique and a near-infrared distributed feedback (NIR-DFB) laser. A Fabry⁻Perot (F⁻P) cavity with an effective optical path length of 49.7 m was sealed and employed as a gas absorption cell. Co-axis cavity alignment geometry was adopted to acquire a larger transmitted light intensity and a higher sensitivity compared with off-axis geometry. The laser frequency was locked to the cavity fundamental mode (TEM00 mode) by using the Pound⁻Drever⁻Hall (PDH) technique continuously. By introducing a cavity length-locking loop, the drift of the cavity length was suppressed, and the stability of the system was enhanced. To demonstrate the efficacy of the system, a C2H2 absorption spectrum near 6534.36 cm−1 was acquired by tuning the laser operation temperature. Measurements of C2H2 samples with different concentrations were carried out, and a good linear relationship between C2H2 concentration and the cavity-transmitted signal voltage was observed. The measurement results showed the system could work stably for more than 2 h without major fluctuations. The Allan variance analysis results demonstrated a detection limit of 9 parts-per-billion (ppb) with an averaging time of 11 s corresponding to a minimum detectable absorption coefficient of 1.1 × 10−8 cm−1

Simultaneous Measurement Method and Error Analysis of the Six Degrees-of-Freedom Motion Errors of a Rotary Axis

Error measurement of a rotary axis is the key to error compensation and to improving motion accuracy. However, only a few instruments can measure all the motion errors of a rotary axis. In this paper, a device based on laser collimation and laser interferometry was introduced for simultaneous measurement of all six degrees-of-freedom motion errors of a rotary axis. Synchronous rotation of the target and reference rotary axes was achieved by developing a proportional⁻integral⁻derivative algorithm. An error model for the measuring device was established using a homogeneous transformation matrix. The influences of installation errors, manufacturing errors, and error crosstalk were studied in detail, and compensation methods for them were proposed. After compensation, the repeatability of axial and radial motion errors was significantly improved. The repeatability values of angular positioning error and of tilt motion error around the y axis and x axis were 28.0″, 2.8″, and 3.9″. The repeatability values of translational motion errors were less than 2.8 μm. The comparison experiments show that the comparison errors of angular positioning error and tilt motion error around the y axis were 2.3″ and 2.9″, respectively. These results demonstrate the effectiveness of our method and the error compensation model

A Method for Simultaneously Measuring 6DOF Geometric Motion Errors of Linear and Rotary Axes Using Lasers

A novel method for simultaneously directly measuring six-degrees-of-freedom (6DOF) geometric motion errors of CNC machine tools was proposed, and a corresponding measurement system was developed. This method can not only be applied for measuring a linear axis, but also for a rotary axis. A single-mode fiber was used to separate the measuring unit from the laser source in order to ensure system thermal stability and measurement accuracy. The method has the advantages of high efficiency and good accuracy, and requires no complicated decoupling calculation. The positioning error of the linear axis and radial motion error of the rotary axis are measured by laser interferometry and other 5DOF geometric motion errors by laser collimation. A series of experiments were performed to verify the feasibility and effectiveness of the developed measurement system

Ontology-Based Architecture Process of System-of-Systems: From Capability Development to Operational Modeling

System-of-systems (SoS) architecture is crucial in managing complex and interconnected systems. However, the description and modeling of SoS architecture pose significant challenges and require a structured and organized approach. In this study, a metamodel for SoS architecture that considers both structural and behavioral perspectives is defined. The metamodel is then mapped to ontologies that are enhanced with a flow-based extension to characterize architecture views. On this basis, an SoS capability ontology (SoSCO) and an SoS operational ontology (SoSOO) are built with factors, relationships, and flows. A four-step architecture process for developing capabilities and a five-step architecture process for operational modeling are provided based on the ontologies. The proposed approach is applied in a search and rescue case study, demonstrating its ability to improve operability in the early design stage. The process is implemented using the Unified Architecture Framework (UAF) so that various stakeholders and engineers can better understand and develop an SoS