The characteristics of weather-related wind load parameters and wind 2 power quality over the Dabanchen strong gale area

Analysis of data from cup and ultrasonic anemometers on a 100 m-tall wind mast in the Dabanchen Canyon reveals that the turbulence intensities, gust factors, and peak factors measured by cup anemometers tend to be severely undervalued compared to longitudinal values from an ultrasonic anemometer, and onsite three-dimensional measurement data are preferred for weather-related wind load calculation. This difference is related to the rotating responses of cup anemometers during wind speed acceleration or deceleration and the higher vertical fluctuation speeds driven by dynamic interactions with the sloped canyon terrain. The higher lateral turbulence is key consideration for determining wind turbine classes in Danbanchen strong wind area. The longitudinal gust and peak factors under wind speeds exceeding 25.0 m s−1 are comparable with those of typhoon-prone open, flat regions. The chances of high turbulence and unstable stratification convective processes are very high; thus, wind power collection efficiencies are not high. Except the longitudinal turbulence integral scale, China’s wind-resistance codes are not applicable due to occasional undesirable strong gales with extraordinary turbulence structures. The measured vertical power spectral density of fluctuating wind in the high-frequency domain cannot reflect the rapidly adapting features of the vast terrain under strong gales.

The characteristics of weather-related wind load parameters and wind power quality over the Dabanchen strong gale area

Analysis of data from cup and ultrasonic anemometers on a 100 m-tall wind mast in the Dabanchen Canyon reveals that the turbulence intensities, gust factors, and peak factors measured by cup anemometers tend to be severely undervalued compared to longitudinal values from an ultrasonic anemometer, and onsite three-dimensional measurement data are preferred for weather-related wind load calculation. This difference is related to the rotating responses of cup anemometers during wind speed acceleration or deceleration and the higher vertical fluctuation speeds driven by dynamic interactions with the sloped canyon terrain. The higher lateral turbulence is key consideration for determining wind turbine classes in Danbanchen strong wind area. The longitudinal gust and peak factors under wind speeds exceeding 25.0 m s−1 are comparable with those of typhoon-prone open, flat regions. The chances of high turbulence and unstable stratification convective processes are very high; thus, wind power collection efficiencies are not high. Except the longitudinal turbulence integral scale, China’s wind-resistance codes are not applicable due to occasional undesirable strong gales with extraordinary turbulence structures. The measured vertical power spectral density of fluctuating wind in the high-frequency domain cannot reflect the rapidly adapting features of the vast terrain under strong gales.

Performance Assessment of Reference Modelling Methods for Defect Evaluation in Asphalt Concrete

The deterioration of road conditions and increasing repair deficits pose challenges for the maintenance of reliable road infrastructure, and thus threaten, for example, safety and the fluent flow of traffic. Improved and more efficient procedures for maintenance are required, and these require improved knowledge of road conditions, i.e., improved data. Three-dimensional mapping presents possibilities for large-scale collection of data on road surfaces and automatic evaluation of maintenance needs. However, the development and, specifically, evaluation of large-scale mobile methods requires reliable references. To evaluate possibilities for close-range, static, high-resolution, three-dimensional measurement of road surfaces for reference use, three measurement methods and five instrumentations are investigated: terrestrial laser scanning (TLS, Leica RTC360), photogrammetry using high-resolution professional-grade cameras (Nikon D800 and D810E), photogrammetry using an industrial camera (FLIR Grasshopper GS3-U3-120S6C-C), and structured-light handheld scanners Artec Leo and Faro Freestyle. High-resolution photogrammetry is established as reference based on laboratory measurements and point density. The instrumentations are compared against one another using cross-sections, point–point distances, and ability to obtain key metrics of defects, and a qualitative assessment of the processing procedures for each is carried out. It is found that photogrammetric models provide the highest resolutions (10–50 million points per m2) and photogrammetric and TLS approaches perform robustly in precision with consistent sub-millimeter offsets relative to one another, while handheld scanners perform relatively inconsistently. A discussion on the practical implications of using each of the examined instrumentations is presented.

Surface Profilometry

As outlined in the previous chapter, existing technologies for surface profilometry show certain drawbacks in terms of resolution, dynamic measurement range, three-dimensional measurement capabilities and speed. The following chapter introduces a novel approach to surface profilometry which aims to provide solutions to the problems named. The basic setup for all experiments is centered around a two-beam interferometer of the Michelson type.

Morphological Measurement of the Femoral Anterior Bow in Chinese Population Based on Three-Dimensional Computed Tomography

Purpose. The femoral anterior bow is an important factor in matching a femoral implant to a femur. However, its morphology in the Chinese population has rarely been reported. In this study, a three-dimensional measurement approach was adopted to provide accurate data. The aim was to supply a reference for designing a long-stemmed femoral prosthesis that is more suitable for Chinese people. Methods. Computed tomography data were collected from both lower limbs of 96 normal volunteers and reconstructed into a three-dimensional model using Mimics software. The parameters of the femoral anterior bow were measured using medical image analysis software. Statistical analysis was conducted using independent-samples and paired-samples t -tests with SPSS software. Results. All the indexes showed significant sexual difference ( P < 0.05 ). The minimum cross-sectional area of the femoral medullary cavity was larger in men ( 10.77 ± 1.53 mm) than in women ( 9.79 ± 1.27 mm). The distance from the position of the maximum curvature to the lower edge of the lesser trochanter was also larger in men ( 60.93 ± 5.81 mm) than in women ( 56.31 ± 2.80 mm). However, the curvature of the femoral medullary cavity centerline was larger in women ( 883.57 ± 249.74 mm) than in men ( 958.79 ± 266.61 mm). The femoral anterior bow morphological indexes of Chinese subjects were different from the published data for other populations. There were no significant differences between left and right femoral anterior bows in either sex ( P > 0.05 ). Conclusion. The three-dimensional measurement approach adopted in this study is more convenient and accurate than previous conventional methods, with high repeatability. The morphological indexes of the femoral anterior bow in this research suggest that population characteristics should be taken into account. This study will provide references for the design of long-stemmed femoral prostheses in the Chinese population.

Development of automatic inspection device for pipe inner surface

Aiming at the problem of 3D measurement of the inner surface of pipe, this paper develops a new structure of pipe inspection device inside the pipe based on the principle of laser triangulation. The device is composed of motion mechanism and image acquisition system. The three-dimensional shape of the inner surface is reconstructed the image pixel offset. The detection device driven by the motion mechanism can realize the automatic detection of different positions. The experiment shows the steps of the three-dimensional measurement of the inner surface of the pipe, verifies the feasibility of this method.

Embedded Design of 3D Image Intelligent Display System Based on Virtual Reality Technology

The previous 3D image intelligent display system is large in size and poor in accuracy, and the display effect and synchronization cannot meet the needs of users. Aiming at this phenomenon, a 3D image embedded intelligent display system based on virtual reality technology is designed. In recent years, with the rapid development of computer technology, three-dimensional measurement technology has become increasingly mature, and three-dimensional information technology has emerged in different fields in real life. With the development of computer science and automatic control technology, more and more intelligent robots appear in production and life. As an important subsystem of intelligent robot systems, the vision system is also receiving more and more attention. The three-dimensional imaging system projects a structured grating on the surface of the target object, uses a digital sensor to collect the deformed structured light image modulated by the surface of the object, and comprehensively uses image processing technology and precision measurement technology to achieve noncontact three-dimensional measurement of the object. This method of number of three-dimensional coordinates has the advantage of not being damaged, high efficiency, high degree of automation, low cost, etc. It has very important significance and broad application prospects for improving product quality and manufacturing efficiency and reducing production costs. Through the investigation and analysis of the existing 3D image intelligent display system embedded, this paper designs and realizes the 3D image intelligent display embedded system, which includes a high-speed structured light projection module, an embedded image acquisition and processing module, and a 3D reconstruction module. Among them, the embedded 3D imaging image acquisition and processing system is an important part of the embedded 3D measurement system, which provides a certain theoretical and practical basis for future in-depth research. The experimental results in this article show that the acquisition module takes 1.934 s to obtain the folded phase of the measured object through phase demodulation and the algorithm, while the phase demodulation and unfolding takes 2.068 s. Therefore, the algorithm needs to be further optimized to speed up the image processing speed and reflect the real-time effect of the system.

Bowel habits and gender correlate with colon length measured by CT colonography

Purpose CT colonography enables three-dimensional measurement of colon length. However, previous studies using CT colonography have not examined the association with gender, age, physique, a history of laparotomy and bowel habits, all possible contributory factors to colon length. The aim of this study is to investigate factors associated with colon length. Materials and methods We conducted a post hoc analysis based on data obtained from a previous multi-center trial including 321 patients with positive fecal immunochemical tests who underwent CT colonography. Colon length was measured using a computer-generated center line and was divided at the iliac crest level into the distal and proximal colons. Bowel habits were classified into three groups: A—daily; B—once every 2 or 3 days; and C—less than once in 3 days. Statistical comparison was made using one-way ANOVA with Bonferroni’s correction. Results A total of 295 patients were analyzed. The entire colon length (cm, mean ± standard deviation) of individual patients was 150.3 ± 18.5 cm and ranged from 109.7 to 195.9 cm. The female colon was significantly longer than the male colon (154.3 ± 18.1 cm vs. 147.1 ± 18.3 cm; p = 0.022). Colon length showed trends associated with age (p = 0.18) and a history of laparotomy (p = 0.14). According to bowel habits, the entire colon measured 147.4 ± 17.9 in group A, 154.7 ± 18.5 in group B and 158.6 ± 18.3 in group C, and significant differences were observed for “A vs. C” (p = 0.002) and “A vs. B” (p = 0.014). In subgroup analysis by colon segment, the proximal colon trended similarly to the entire colon while there were no trends for the distal colon. Conclusions This study has clearly demonstrated that bowel habits and gender both correlate with the length of the entire colon measured by CT colonography, and in particular, the proximal colon. Secondary abstract Using CT colonography, we measured the colon length in 295 patients. The entire colon length was 150.3 ± 18.5 cm on average. Females and constipated (less frequent defecation) patients have a significantly longer colon, and in particular, the proximal colon. Colon length showed trends associated with age and a history of laparotomy.