Fractal Analysis of Fuel Nozzle Surface Morphology Based on the 3D-Sandbox Method.

The dual oil circuit centrifugal fuel nozzle is made of martensitic stainless steel, which has complex morphological characteristics. The surface roughness characteristics of the fuel nozzle directly affect the degree of fuel atomization and the spray cone angle. The surface characterization of the fuel nozzle is investigated by the fractal analysis method. A sequence of images of an unheated treatment fuel nozzle and a heated treatment fuel nozzle are captured by the super-depth digital camera. The 3-D point cloud of the fuel nozzle is acquired by the shape from focus technique, and its three-dimensional (3-D) fractal dimensions are calculated and analyzed by the 3-D sandbox counting method. The proposed method can characterize the surface morphology well, including the standard metal processing surface and the fuel nozzle surface, and the experiments show that the 3-D surface fractal dimension is positively correlated with the surface roughness parameter. The 3-D surface fractal dimensions of the unheated treatment fuel nozzle were 2.6281, 2.8697, and 2.7620, compared with the heated treatment fuel nozzles dimensions of 2.3021, 2.5322, and 2.3327. Thus, the 3-D surface fractal dimension value of the unheated treatment is larger than that of the heated treatment and is sensitive to surface defects. This study indicates that the 3-D sandbox counting fractal dimension method is an effective method to evaluate the fuel nozzle surface and other metal processing surfaces.

3D Measurement Method for Saturated Highlight Characteristics on Surface of Fuel Nozzle.

Saturated highlights on metal surfaces reduce the detection accuracy of fuel nozzles. In this paper, we propose an image inpainting method with a saturated highlight based on the statistics of similar patches used in prior segmentation of the subregion. The sequence image acquisition is based on the shape from focus in the five-axis platform. By our method, the focus measure (FM) operator and the window size are evaluated using the sharpness evaluation curve and calculating time. We observe that the detection accuracy is improved when the highlight area is filled by the highlight-free area within the same segmentation region. There are fewer deviation points in the three-dimensional (3D) point cloud that are extracted from the sequence images. The inlet circle and the outlet circle of the fuel nozzle are both detected by the two-dimensional (2D) Hough Transform (HT) method. Our experiments show that the method yields better results in 3D detection of the key parameters of fuel nozzles with the saturated highlight characteristics.

Benefits of applying virtual reality in pelvic movement training through a Wii Fit: a randomized controlled trial.

BACKGROUND: Pelvic movement training has become compulsory for part of medical students. An increasing amount of research has focused on the influence of virtual reality (VR) on learning effectiveness. However, its application to pelvic floor muscles or pelvic movement training is still in its infancy. We compared the effectiveness of conventional pelvic movement training with or without VR-assisted pelvic movement training for student learning. METHODS: We recruited 44 university students (16 male and 28 female participants; average age = 19.7 ± 0.31 years) who had not previously received pelvic movement education or training. The participants were randomly assigned into traditional and experimental groups to acquire pelvic movements and relevant knowledge. The traditional group received conventional classes (about 15 min), whereas the experimental group received both conventional classes and VR-assisted teaching (additional VR session took approximately 25-45 min depending on the speed of movement of each participant). The participants were asked to control the trajectory of the centre of pressure on the Wii Fit balance board and build-in games to learn pelvic movements. We conducted evaluations before, immediately after, and 2 weeks after the experiment, based on the scores of written and practical examinations. The experimental group was also asked to complete a questionnaire during the posttest. RESULTS: We carried out two-way repeated measures ANOVA and discovered that the written examination scores indicated a significant Time × Group interaction (p=0.015). In each group, the written and practical examinations in the posttest and follow-up test exhibited significantly improved results compared with the baseline value (p <0.001, except for traditional group of written exam in follow up test vs. baseline p=0.001). The written examination in the follow-up test did not decline significantly compared with those in the posttest, but the practical examination in the follow-up test was decline significantly compared with those in the posttest (p=0.033). The experimental group had superior overall performance in the practical examinations than the traditional group (experimental group: mean = 76.27, 95% confidence level [CI] = 70.84-81.71; traditional group: mean = 64.21, 95% CI = 58.78-69.65). No significant difference in the written examination between two groups. The percentage for agreement ratio on the usefulness, ease of use, users' intention to continue using the VR-assisted teaching is high (95.5-100%). CONCLUSIONS: The results of this study suggested that conventional and conventional + VR teaching were both effective. However, the incorporation of VR stimulated learning motivation and facilitated precise performance of pelvic movements. It is recommended that pelvic floor muscles training could be supplemented with VR or games to increase students' motivation and understanding how to perform pelvic movements.

Seasonal variation in the frequency of venous thromboembolism: An updated result of a meta-analysis and systemic review.

OBJECTIVE: Venous thromboembolism, including deep vein thrombosis and pulmonary embolism, is likely to cause the death of both medical and surgical patients. Despite some evidence of seasonal variation in the incidence of venous thromboembolism, the existing studies obtain contradictory results. A temporal pattern for pulmonary embolism is known, but data on deep vein thrombosis are inconclusive. The purpose of this study is to make a meta-analysis and systematically review the literature about seasonal variations of pulmonary embolism and/or deep vein thrombosis in order to objectively diagnose venous thromboembolism. METHODS: According to dichotomous data, risk ratios (RRs) and 95% confidence intervals (CIs) were used to compare the incidence of venous thromboembolism in different seasons. The research was classified according to pulmonary embolism mortality, pulmonary embolism/deep vein thrombosis incidence, latitude/elevation/climatic types, and monthly incidence for four subgroup comparisons. There were a total of 23 eligible studies, in which 40,309 patients with venous thromboembolism were compared. RESULTS: The pooled total venous thromboembolism incidence was 27.2% in winter, 23.1% in spring, 24.6% in summer, and 25.1% in autumn. According to the results of pooled analysis, the incidence of venous thromboembolism in winter was much higher than that in summer (RR = 1.12, 95% CI: 1.01-1.24, adjusted P = .04), especially deep vein thrombosis. Moreover, the incidence of venous thromboembolism in summer and autumn was lower than that in winter in low-latitude (<200 m) areas and median low-latitude (0-50°-N) areas. Interestingly, the frequency of pulmonary embolism mortality was the largest in spring and smallest in summer (spring > winter ≈ autumn > summer). For monthly data, a statistically significantly lower incidence of venous thromboembolism was observed in May and July than in October. CONCLUSIONS: The study revealed a significantly higher incidence of venous thromboembolism and deep vein thrombosis in winter than in summer. Pulmonary embolism mortality occurred more frequently in spring than during other seasons. A statistically significantly lower incidence of venous thromboembolism was observed in May and July compared with that in October.

A Scoping Review of The Efficacy of Virtual Reality and Exergaming on Patients of Musculoskeletal System Disorder.

To assess the effects of virtual reality on patients with musculoskeletal disorders by means of a scoping review of randomized controlled trials (RCTs). The databases included PubMed, IEEE, and the MEDLINE database. Articles involving RCTs with higher than five points on the Physiotherapy Evidence Database (PEDro) scale were reviewed for suitability and inclusion. The methodological quality of the included RCT was evaluated using the PEDro scale. The three reviewers extracted relevant information from the included studies. Fourteen RCT articles were included. When compared with simple usual care or other forms of treatment, there was significant pain relief, increased functional capacity, reduced symptoms of the disorder, and increased joint angles for the virtual reality treatment of chronic musculoskeletal disorders. Furthermore, burn patients with acute pain were able to experience a significant therapeutic effect on pain relief. However, virtual reality treatment of patients with non-chronic pain such as total knee replacement, ankle sprains, as well as those who went through very short virtual reality treatments, did not show a significant difference in parameters, as compared with simple usual care and other forms of treatment. Current evidence supports VR treatment as having a significant effect on pain relief, increased joint mobility, or motor function of patients with chronic musculoskeletal disorders. VR seems quite effective in relieving the pain of patients with acute burns as well.

Seasonal incidence of ruptured abdominal aortic aneurysm and the influence of atmospheric pressure: a systematic review and meta-analysis.

Ruptured abdominal aortic aneurysm (rAAA) is a life-threatening condition with a high mortality rate. Seasonal variations in the incidence of rAAA and the influence of atmospheric pressure have been studied throughout decades; however, the conclusions are contradictory. Therefore, we aimed to conduct a meta-analysis and systematic review of literature on seasonal variations in rAAA incidence and the influence of atmospheric pressure. Studies investigating seasonal variations in rAAA incidence and influence of atmospheric pressure were retrieved. For dichotomous data, we generated risk ratios (RRs) and 95% confidence intervals (CIs) for rAAA incidence compared among seasons. The studies were subdivided according to latitude, elevation, and climatic types, for subgroup comparisons. Studies reporting monthly incidence and seasonal mortality were further investigated. For continuous data, standardized mean differences (SMDs) and 95% CIs were generated for atmospheric pressure comparisons. Twenty-four eligible studies were included, comprising a total of 38,506 patients with rAAA. Pooled rAAA incidence was 25% in spring, 23% in summer, 26% in autumn, and 26% in winter. Pooled analysis demonstrated a statistically significant higher rAAA incidence in winter than in summer (RR 1.10, P = 0.04) and in autumn than in summer (RR 1.11, P < 0.00001). However, there was no statistically significant difference among other seasons. In the study of the influence of atmospheric pressure, no statistically significant difference was observed. In conclusion, our study revealed a higher incidence of rAAA in autumn and winter than in summer; however, atmospheric pressure was found to exert no influence.

Impact of ambient temperature and atmospheric evaporation on the incidence of acute deep venous thrombosis in the northeast of China.

BACKGROUND: Meteorological variables have been reported to be associated with increased morbidity; however, fewer studies have study the correlations between the occurrences of acute deep venous thrombosis (DVT) and meteorological variables. METHODS: Data relating to hospital admissions with DVT in Shenyang were collected retrospectively for a ten year period for which corresponding meteorological recordings were available. Using a time-series design and distributed lag nonlinear models (DLNM), we estimated the relative risk (RR) of DVT presentation associated with mean daily temperatures, including cumulative RR for a 28-day period, and RR for individual daily lags through 28 days. RESULTS: We found significant seasonal variation in DVT with a winter peak. A significant correlation was found between the ambient temperature and the number of hospital admissions for DVT. The lower the average, minimal, and maximal ambient temperature, the higher the incidence of DVT (P=0.001, P=0.002, and P<0.001). Furthermore, high evaporation (P=0.026) and high vapor pressure (P=0.003) on the date of admission was associated with an increase in the rate of presenting with DVT. Based on a time-series analysis, this study showed that the associations between mean daily temperature and DVT presentation were not monotonic. Compared to centered temperature at 8 °C, the cumulative 28-day (lag 0 to lag 27) RR was significantly elevated at -16 °C, -15 °C, -14 °C, and -13°C for DVT (P<0.05). To the extreme low temperature (-17.7 °C) in Shenyang, the RR of cumulative 8-day (lag 0 to 7 days) was remarkably increased for DVT (RRlag8-day=1.03, 95% CI: 1.01-1.05). For the extreme high temperature, nevertheless, no particular finding was detected regarding acute and prolonged effects for DVT. CONCLUSIONS: In general, low ambient temperature was significantly associated with DVT presentations in comparison with that of high temperature. The effects of cold were delayed by one week. DVT is particularly associated with high evaporation and high vapor pressure.

The effect of ambient temperature on the onset of acute Stanford type B aortic dissection.

BACKGROUND: The aim of this work was to study the associations between weather conditions and the occurrence of type B acute aortic dissections (ABAD). PATIENTS AND METHODS: This study was a retrospective review of all ABAD cases between January 1st, 2006 and December 31st, 2015. Using a time-series design and distributed lag non-linear models (DLNM), we estimated the relative risk (RR) of ABAD presentation associated with mean daily temperatures, including cumulative RR for a 28-day period, and RR for individual daily lags through 28 days. RESULTS: A total of 213 patients were admitted with ABAD. A significant association was found between the daily maximal temperature and the number of hospital admissions for ABAD. The lower the maximal temperature, the higher the incidence of ABAD (P = 0.044). Furthermore, the onset of ABAD was higher in winter than in summer and autumn (P = 0.009 and P = 0.001). Based on a time-series analysis, this study showed that the associations between mean daily temperature and ABAD presentation were not monotonic. Compared to the centered temperature at 8°C, the cumulative 28-day (lag 0 to lag 27) RR was significantly elevated at - 20 °C and - 19 °C for ABAD (RR = 1.39; 95%CI: 1.02, 1.98 and RR = 1.36; 95%CI: 1.02, 1.98). At the extreme low temperature (- 17.7 °C) in Shenyang, the cumulative 14-day (lag 0 to 13 day) and 21-day (lag 0 to 20 day) RR were remarkably increased for ABAD (RRlag14-day = 1.34; 95%CI: 1.08, 1.40 and RRlag21-day = 1.06; 95%CI: 1.06, 1.23). For the extreme high temperature, however, no particular finding was detected regarding acute and prolonged effects on ABAD. CONCLUSIONS: In general, low ambient temperature was significantly associated with ABAD presentations in comparison with high temperature. The effects of cold were delayed by two weeks and persisted for a few days.