به جمع مشترکان مگیران بپیوندید!

تنها با پرداخت 70 هزارتومان حق اشتراک سالانه به متن مقالات دسترسی داشته باشید و 100 مقاله را بدون هزینه دیگری دریافت کنید.

برای پرداخت حق اشتراک اگر عضو هستید وارد شوید در غیر این صورت حساب کاربری جدید ایجاد کنید

عضویت

فهرست مطالب h. wang

  • Y. Long *, H. Wang, R. Wang, B. He, Q. Fu, R. Zhu
    The high-speed centrifugal pump plays a crucial role in fields such as aerospace and petrochemical industries, owing to its characteristics of elevated rotational speed and high head. During high-speed operation, the centrifugal pump is prone to cavitation, which alters the fluid flow state within the pump, leading to vibrations, noise, and a sudden decrease in pump head and efficiency. Simultaneously, the collapse of cavitation bubbles generates impact pressure that can damage the pump's internal flow components, significantly reducing its operational lifespan and causing severe consequences. Moreover, under constant-flow conditions, the absolute and relative velocities of the fluid at the impeller inlet are functions of the suction pipe diameter. Therefore, there exists an optimal value for the impeller inlet diameter to enhance the centrifugal pump's resistance to cavitation. Similarly, the different geometric and structural parameters of the inducer also influence the hydraulic performance of the centrifugal pump. The focus of this study is on the external characteristics and internal flow patterns of an optimized high-speed centrifugal pump. In this paper, the entire flow field of the model pump is numerically simulated using ANSYS CFX software. The performance and overall flow field state of the high-speed centrifugal pump under different impeller configurations and inlet diameters are explored. The influence of blade wrap angle and inlet diameter on the high-speed centrifugal pump is revealed, providing a theoretical basis for subsequent optimal design.
    Keywords: High-Speed Pumps, Cavitation Performance, Multi Condition Operation, Hydraulic Performance}
  • H. Wang *, H. Ding

    A confirmatory method for the determination of tetracycline antibiotics (TCs) in Chinese mitten crab has been developed for the first time. The method comprises two stages: pretreatment of the samples and instrumental analysis. The samples are treated with Na2EDTA–McIlvaine buffer followed by extraction. The extract is then analyzed with ultra-performance liquid chromatography tandem high-resolution mass spectrometry (UPLC-HRMS). Four mostly used TCs, including tetracycline, oxytetracycline, chlortetracycline, and doxycycline, were detected in 10 min. The specificity was confirmed via the retention time and their high-resolution mass spectra. In the range of 50-500 μg/kg, the linear regression coefficients (R2) for all analytes were greater than 0.9985. Recoveries at three concentration levels were between 90.3% and 106.2%. The within-laboratory reproducibility was precise. The decision limit (CCα) and detection capability (CCβ) of the method were determined using the permitted limit (100 μg/kg) of TCs. The detection results of TCs in 12 batches of Chinese mitten crab showed that no target residues were detected. This comprehensive method is compliant with the 2002/657/EC decision. It could be applied for the determination of TCs in Chinese mitten crab samples and potentially in other aquatic products.

    Keywords: Tetracycline, Confirmatory Method, Chinese Mitten Crab, UPLC, HR-MS}
  • W. Cao, X. Yang *, H. Wang, X. Leng
    To investigate the gas-liquid two-phase flow characteristics in an emergency rescue drainage pump, the MUSIG model was adopted to analyze the effect of the gas phase on the internal flow characteristics of the pump. The results show that the gas phase predominantly accumulated in the impeller region, with significant tendencies for large diameter bubbles to fragment into smaller diameter bubbles. The bubbles of the impeller blades converged towards the middle zone of the blade near the hub, forming an air pocket that obstructed the flow passage through the impeller. Such findings ultimately resulted in a loss of pump performance. Moreover, as the diameter of inlet bubble increased, there was a greater tendency for the gas phase to converge into a concentration distribution, leading to unfavorable flow conditions in the pump. This phenomenon ultimately led to a decline in pump performance and may have resulted in the loss of water conveyance functionality. Meanwhile, the Ω method was used to investigate the vortex flow within the drainage pump under different gas contents. As the inlet gas volume fraction increased, the vortex area expanded and the vortex tended to fragment into multiple smaller pieces, resulting in the formation of more complex structures.
    Keywords: Gas-Liquid Two-Phase Flow, MUSIG Model, Gas Phase Diameter, Vortex}
  • G. Yang, L. Gao *, C. Ma, H. Wang, N. Ge
    To improve the aerodynamic characteristics of compressor blades, a novel asymmetric leading edge (ASYLE) has been introduced and shown to offer superior performance. However, the aerodynamic robustness of such specially designed leading edge (LE) remains unclear due to the considerable uncertainty problems it presents. This paper investigates the robustness of ASYLE blade under both geometric and operational uncertainties. Profile deviations within ±0.05mm were introduced to investigate the influence of manufacturing errors. In addition, the perturbated inflow angles between ±0.375° were considered for uncertain inflow conditions. The statistic aerodynamic performance as well as operating dispersibilities at Ma=0.7 were obtained by the non-intrusive polynomial chaos (NIPC) method. The results show that considering uncertain profile errors, the operating range of ASYLE blade is 2.3° wider than original leading edge (ORILE) blade and the dispersion of total pressure loss can be reduced by 53.1% at β1=45.8°. Regarding uncertain inflow angle variations, the total pressure loss dispersion of ASYLE blade can be reduced by 93.8% at β1=50.8°. The ASYLE shows better overall aerodynamic robustness than ORILE upon considering uncertainty limits. The influence propagations in the flow fields of both uncertainties were further analysed, which revealed that the variations of separation bubble structure near LE are the direct cause to the aerodynamic uncertainties. The ASYLE design effectively controls the size and variation of LE separation bubble and thus demonstrates better aerodynamic robustness.
    Keywords: Asymmetric leading edge, Aerodynamic robustness, Profile error, Inflow angle perturbation, Uncertainty quantification}
  • T. Guo, Y. Yu, H. Wang, B. Zhou, X. Zhang, D. Zhang, H. Li*, Z. Sun
    Background

    To investigate the use of uniportal video-assisted thoracoscopic surgery (U-VATS) in the treatment of non-small cell lung cancer (NSCLC).

    Materials and Methods

    A total of 82 patients with early NSCLC in our hospital from May 2019 to January 2021 were enrolled to this study. Forty-one patients treated with spontaneous breathing U-VATS were the research group (RG), and 41 with conventional thoracoscopy were the control group (CG). Fasting peripheral blood was drawn from patients before (T0), one (T1) and three days after surgery (T2), respectively. White blood cells (WBC), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), matrix metalloproteinase-9 (MMP-9) and T-lymphocyte subsets were measured in the blood. In addition, we counted the conversion rate to open chest and tracheal intubation in the RG, and compared the operation time, intraoperative bleeding, chest drainage, chest tube retention time, antibiotic application time, postoperative hospital stays and complications between groups. Finally, a 1-year prognostic follow-up was performed to record overall survival, chemotherapy rate, and recurrent metastasis rate.

    Results

    At T1, WBC, IL-6, TNF-α, and MMP-9 were lower in the RG than in the CG, while immune function was better in the RG at T1 and T2 (P<0.05). Complication rates were lower in the RG than in the CG when compared (P>0.05). The prognosis of 1-year overall survival, chemotherapy rate, and recurrence rate were not different between the two groups (P>0.05).

    Conclusion

    Spontaneous breathing U-VATS can effectively reduce the inflammation and enhance the stability of immune function in NSCLC patients undergoing surgery.

    Keywords: Video-assisted thoracic surgeries, non-small cell lung cancer, immune system phenomena, inflammation, postoperative complications}
  • H. W. Fan, Z. G. Huang *, H. Wang, Z. H. Chen, X. Y. Liu, F. J. Xiao, R. X. Qiu
    The hollow projectile is a new type of projectile that has complex water entry hydrodynamics characteristics and has attracted significant attention in recent years. As such, it is important to investigate the effects of different entry velocities and aperture diameters on the cavity morphology, cavitation, dynamics, and motion characteristics of hollow projectiles when entering water at high speeds. In this study, four stages of an open cavity, cavity stretching, cavity closure, and cavity contraction in the water entry processes of a hollow projectile at 50–200 m/s and four aperture diameter projectiles at 100 m/s were studied using the volume of fluid (VOF), realizable k-ε turbulence, and Schnerr-Sauer cavitation model. With an increase in the speed, the depth of the cavity closure increases, thereby advancing the closure time. The timing of the surface closure at 50 m/s is clearly different from that at 100–200 m/s. Cavitation is not obvious and is near the cavity wall at 50 m/s, although the entire cavity is almost filled with vapor at 100–200 m/s. The friction resistance has two step points when impacting the water surface and entering the water completely. As the velocity increases or the aperture ratio reduces, the splash is higher, the cavity volume is larger, the cavitation phenomenon is more obvious, the cavity closure time is delayed, and the frictional resistance of the projectile is greater. The results of this study can guide the production and application of hollow projectiles in the future.
    Keywords: Hollow projectile, High-speed water entry, Cavity shape, fluid dynamics, Numerical calculation}
  • Z. Tang, H. Wang, S. Liu*, D. Lu, Y. Tang

    In order to improve the intelligent mechanized harvesting ability of small green vegetables, a self-propelled small green vegetables intelligent combine harvester was designed according to its planting mode and agronomic requirements. It can simultaneously meet the requirements of mechanized harvesting operations for cutting, clamping and conveying, and collecting of small green vegetables. Additionally, this model adopts the electric drive chassis of the pure electric drive intelligent battery management system based on BMS technology, which realizes the intelligent balance matching of power. The harvester adopts the intelligent control system controlled by PLC to automatically detect the walking speed of the machine, the height of the cutter and the transmission speed, etc., so as to realize the rapid matching of each working part. It was found that the proportion of electricity consumption of the harvester in two hours was 23%, with an average harvesting efficiency of 0.16 hm²/h. Besides, the average loss rate was 4.22% during the normal operation of the harvester. This study provides a reference basis for the intelligent mechanized harvesting of small green vegetables.

    Keywords: Electric walking chassis, Human-machine interface, Intelligent control system, Vegetable harvesting, Self-propelled harvester}
  • H. Wang *, Q. F. Ying, E. Lichtfouse, C. G. Huang
    Gradient metal foam is an advanced heat transfer material that decreases resistance to bubble escape and enhances the transfer of boiling heat. In this study, boiling heat transfer and bubble behavior were studied in an experimental set-up with copper foam bilayers configurated either in positive or inverse gradients, utilizing deionized water as working fluid. Positive gradient refers to arranging metal foam layers with high pore density at the bottom, above the heat source, and low pore density on the top. Results show that the heat transfer is higher for gradient metal foam surfaces, of 6.14×105 W/m2, versus a uniform metal foam surface, of 3.94×105 W/m2. For the positive gradient configuration, boiling heat transfer performance first increased with the pore density, then decreased when the pore density was higher than 60 pores per inch (PPI). By contrast, for the inverse gradient, the heat transfer performance was nearly constant with increasing pore density. At the low pore density, the inverse gradient performed better than the positive gradient during the whole boiling process. At high pore density, the positive gradient structure performed better in heat transfer at the early boiling stage. Three main types of bubble escape were observed: For the positive gradient bilayer, the bubbles moved up or down without lateral interference. In contrast, for inverse gradient, the bubbles mostly escape from the sides, which is easy to induce bubble merging. The inverse gradient surface generates larger bubbles, while the positive gradient surface produces a higher frequency of bubble detachment. Accordingly, two liquid replenishment models are proposed: for the positive gradient, external liquid replenishes from the side into the copper foam, while for inverse gradient, the liquid is mainly replenished from the top.
    Keywords: Gradient copper foam, Liquid replenishment, Bubble behavior, Heat transfer enhancement, Multiphase flow}
  • H. Wang *, R. Rodriguez-Lopez
    The theory of interval-valued difference equations under $gH$-difference is an interesting topic, since it can be applied to study numerical solutions to interval-valued or fuzzy-valued differential equations. In this paper, we estimate the number of solutions to a class of first-order interval-valued difference equations under $gH$-difference, which reveals the complexity of the stability analysis in this area, as well as the difficulty for prediction and control problems. Then, based on the relative positions of initial values and equilibrium points, we provide sufficient conditions for the existence of convergent solutions. We also provide examples to illustrate the validity of our results.
    Keywords: Interval-valued difference equations, gH-difference, equilibrium points, Convergence}
  • R. Wang, Z. LI, Y. Wang, H. Wang*

    Pulmonary ventilation/perfusion (V/Q) scintigraphy is often used for the diagnosis of pulmonary embolism. However, it should be noted that the perfusion defect shown by pulmonary perfusion imaging is not the only manifestation of pulmonary embolism. Any disease that causes pulmonary vasculature stenosis and occlusion can cause pulmonary blood flow perfusion impaired. We report a case of fibrosing mediastinitis (FM) with pulmonary hypertension as a complication of pulmonary artery and pulmonary vein stenosis. Based on clinical symptoms, laboratory test and multiple radiographic findings, the diagnosis of FM was established. The patient underwent balloon dilation and stent implantation of right upper lobe pulmonary vein, as well as balloon dilatation of right upper lobe pulmonary artery, whose symptoms was immediately improved during the following investigation.

    Keywords: pulmonary perfusion scintigraphy, fibrosing mediastinitis, pulmonary artery stenosis, pulmonary vein stenosis, interventional therapy, SPECT, CT}
  • Z. Yang, B. Liu, X. Mao *, B. Zhang, H. Wang
    We perform a thorough numerical analysis of the impact of inflow conditions on the aerodynamic performance of a tandem cascade. In particular, we investigate the effects of the incidence angle and the inlet boundary layer (IBL) thickness on the three-dimensional flow field structure and aerodynamic performance. Our results show that the gap flow strength of the tandem cascade decreases with the increase of incidence angle, and it can effectively reduce the mixing of the wakes of the forward blade (FB) and rear blade (RB). In turn, this prevents the passage vortex (PV) in the RB passage from developing along the circumferential direction. The occurrence of IBL does not modify the effects of the incidence angle on the tandem cascade, however, it reduces the load of the RB and the gap flow strength near the endwall. Under all incidence angles, IBL increases the total pressure loss of the tandem cascade, and decreases the static pressure rise (except for an incidence angle equal to -6°). The maximum loss increment is at 2° incidence angle, and the maximum static pressure rise decrement is at 6° incidence angle (Thick-IBL condition) or 7° incidence angle (Thin-IBL condition). Furthermore, we found that the presence of IBL changes the minimum loss condition from 0° (design condition) to -2° incidence angle. Our results thus indicate that in the practical engineering application of the tandem cascade, the reality that IBL degrades the tandem cascade performance in the full incidence angle range should be considered. And the strong endwall secondary flow effect caused by IBL should be considered in the tandem cascade three-dimensional design, so that the tandem cascade two-dimensional performance advantage can be better played.
    Keywords: Tandem cascade, Inlet boundary layer, Total pressure loss, Corner separation, Compressor}
  • H. Chen, Y. Shao, H. Wang, H. Gu, Y. Duan, A. Feng, Y. Huang, C. Chen*, Z. Xu
    Background

    To investigate the performance of Auto-Planning intensity modulated radiation therapy (IMRT) plans for patients with central lung cancer and to determine whether Auto-Planning improves the quality of IMRT plans.

    Materials and Methods

    Thirty patients treated with IMRT for central lung cancer were replanned with the Pinnacle3 Auto-Planning module. The dose distribution at the target, organ at risk (OAR) sparing, dose falloff in the five rings outside of target, monitor units (MUs), planning time, and dosimetric verification in terms of the γ passing rate were evaluated. A Wilcoxon signed-rank test was performed to assess differences between groups (p<0.05).

    Results

    The target homogeneity in the Auto-Planning were significantly better than that in the manual plans, the target conformity in both groups were similar. The Auto-Planning plans yielded lower V5, V10, V13, V20, V30, V40 values, mean lung dose of total lung (p<0.01), and Dmax of spinal cord (p<0.01) and V30 of heart (p<0.01). No significant difference was found for the V40 of the heart (p=0.203). The Auto-Planning module reduced the Dmean, D2 and D5 values in all rings outside of PTV. The planning time was 52.5% shorter for Auto-Planning plans than for manual plans (p<0.01), and 4.4% additional MUs were required with Auto-Planning. No difference was observed for the γ passing rate.

    Conclusion

    Auto-Planning for central lung cancer could improve homogeneity of target volumes, significantly delivery lower dose to OARs and steeper dose falloff outside of tumors while reducing the planning time.

    Keywords: Pinnacle auto-planning, IMRT, lung cancer}
  • Y. Shao, H. Chen, H. Wang, Y. Cheng, Z. Zhu, W. Zhuo, Q. Kong, Z. Xu*
    Background

    To investigate the maximum distance from lesions to the single-isocenter that can ensure the accuracy of dose delivery for single-isocenter/two-lesions intensity modulated radiotherapy (IMRT) lung stereotactic body radiation therapy (SBRT).

    Materials and Methods

    We employed a lung phantom made of acrylic material. Sixteen gross tumor volumes (GTVs) of the same shape and size were delineated on the CT images. The single-isocenter was placed on the center of the first GTV (GTV1). Six GTV centers were located at left and were 2-7 cm away from the single-isocenter. Nine GTV centers were in the 45° direction and were 2-10 cm away from the single-isocenter. Plans were created for the first planning target volume (PTV1) and other fifteen PTVs separately with the same isocenter. Compass was used to verify the treatment plans. γ analysis was carried out with criteria of 2% / 2 mm. The passing rate shall over than 90%. If the passing rate of γ analysis was lower than 90%, two-isocenter plan was created and carried out γ analysis as well.

    Results

    According to the γ analysis, when the distance from lesions to the single-isocenter was more than 6cm, both in the horizontal or 45° direction, the passing rate was lower than 90%. Based on γ analysis, two-isocenter plans were created. After verification, the passing rate was higher than 90%.

    Conclusions

    The maximum distance of using single-isocenter to treat multiple lung lesions is 5 cm. The result provides a reference for our center and other centers when using this technique to treat multiple lung lesions.

    Keywords: Multiple lung lesions, single-isocenter, SBRT, dose accuracy}
  • H. Wang, B. Liu, B. Zhang, Z. Chen

    It has been proved that suitable slot structure of compressor slotted blade can generate high-momentum jet flow through pressure difference between the pressure and suction surface, the slot jet flow can reenergize the local low-momentum fluid to effectively eliminate the flow separation. In order to investigate and evaluate the impact of full-span slot and blade-end slot on the performance of the post-loaded blade, which has serious flow separation on the suction surface both near blade midspan and endwall, a diffusion stator cascade with large camber angle is selected as the research object. Firstly, the blade-end slotted scheme and the full-span slotted scheme are set up. Then the performance of datum cascade and two slotted cascades is computed in the wide incidence angle range of -8º to 6º at the Mach number of 0.7, the corresponding blade-chord-based Reynolds number 𝑅𝑒𝐶 is 7.7 × 105 . Finally, the performance of the three cascades is analyzed and compared. The results show that, in the computational incidence angle range, both of the two slotted schemes can reduce the total pressure loss for datum cascade and enhance its pressure diffusing capability. However, compared with the blade-end slot, the full-span slot has a better comprehensive control effect on the corner separation and the boundary layer separation near blade midspan, hence, compared with those of blade-end slotted cascade, the total pressure loss coefficients and the static pressure coefficients of full-span slotted cascade are respectively further decreased and increased. Under the blowing effect of full-span slot jet, the total pressure loss coefficients of datum cascade are significantly decreased, ranging as high as 21.2%, 23.1%, 24.5% and 23.4% under the incidence angles of 0°, 2°, 4° and 6°, respectively. The full-span slotted scheme has a better adaptability to wide incidence angle range, it can effectively broaden the available incidence angle range for datum cascade.

    Keywords: Flow separation, Blade-end slot, Full-span slot, Post-loaded blade, Total pressure loss, Pressurediffusing capability}
  • H. Wang, B. Liu†, B. Zhang

    Suitable slot structure of the compressor blade can generate high-momentum jet flow through pressure difference between the pressure and suction surface, it has been proved that the slot jet flow can reenergize the local low-momentum fluid to effectively suppress the flow separation on the suction surface. In order to explore a slotted method for better comprehensive suppressing effects on the boundary layer separation near blade midspan and the three-dimensional corner separation, a diffusion stator cascade with large camber angle is selected as the research object. Firstly, the Slotted_1 and Slotted_2 whole-span slotted schemes are set up, then the Slotted_3 scheme with whole-span slot and blade-end slots is proposed, finally the performance of original cascade and slotted cascades is computed under a wide range of incidence angles at the Mach number of 0.7. The results show that: in the full range of incidence angles, compared with the whole-span slotted cascades, the development of the endwall secondary flow on the suction surface of Slotted_3 cascade is effectively suppressed, the degree of the mutual interference between the secondary flow and the main flow is reduced. Besides, on the suction surface of Slotted_3 cascade, the boundary layer separation near blade midspan and the corner separation are basically eliminated. As a result, compared with those of original cascade, the total pressure losses of Slotted_3 cascade are reduced in the full range of incidence angles, and its operating range of incidence angles is broadened. Moreover, compared with the whole-span slotted schemes, Slotted_3 scheme has a better adaptability to wide range of incidence angles.

    Keywords: High-momentum jet, Boundary layer separation, Three-dimensional corner separation, Whole-spanslot, Blade-end slots, Total pressure loss}
  • X. Xu, J. Wang, Q. Yang, H. Liu, H. Wang

    A preheating exchanger is developed for improving acidic water degassing. Reasonable optimization of dualinlet swirl heating tubes is analyzed by computations of the flow and heat transfer. The comparisons of the swirl number and circumferential average Nusselt number between isobaric injection and isokinetic injection are performed. Inlet area ratios ranging from 0.1 to 0.9 exhibit an important influence on the flow phenomena and the heating performance. A lower value of inlet area ratio leads to the tendency for the fluid passing through inlet 2 to move upstream of inlet 2 and results in more vortex pairs between inlets 1 and 2. An inlet area ratio value of 0.5 exhibits the largest global average Nusselt number, normalized Nusselt number, and thermal performance factor. The optimized inlet area ratio is suitable for improving the degassing efficiency

    Keywords: Preheating degassing, Dual-inlet swirl, Flow, heat transfer, Numerical simulations}
  • در این مقاله، وجود جوابهای معادلات دیفرانسیل بازه – مقدار مرتبه اول، با محدودیتهای طول را تحت gH-دیفرانسیل پذیری مورد ملاحظه قرار میدهیم. با استفاده از نظریه نقطه ثابت نگاشته ای فشرده روی فضاهای متریک، برخی از شرایط کافی برای وجود جوابها را ارایه میدهیم. در پایان این مقاله، برای نشان دادن نتایج مثالهایی ارایه شده است.

    H. Wang*, R. Rodr´ıguez-L´opez

    In this paper, we consider the existence of solutions to first-order interval-valued differential equations with length constraints under gH-differentiability. By using the fixed point theory of compact maps on metric spaces, we provide some sufficient conditions for the existence of solutions. At the end of this paper, we show some examples to illustrate our results.

    Keywords: Interval-valued differential equations, gH-differentiability, length constraints, switching points}
  • J. Sahandi, P. Sorgeloos, H. Xiao, H. Wang, Z. Qi, Y. Zheng, X. Tang*

    Because of the importance of rotifers as an adequate live food in larviculture, this study was conducted to evaluate probiotic potency of four microorganisms, Candida parapsilosis, Pseudoalteromonas flavipulchra, Lactobacillus sakei and Bacillus natto on suppression of Vibrio species and increasing population growth, enzymes activity and nutrients retention in the rotifer, Brachionus plicatilis. Four experimental and a control treatment, each with four replicates, with the concentration of 108 CFU/mL-1 for each strain were applied. The results demonstrated that L. sakei and B. natto successfully suppressed Vibrio in experimental treatments and increased population growth and nutrients retention. The longevity of B. natto was recorded as the best in long-term inoculation than other treatments and the control in a way that after 8 days of rotifers starvation, the count of B. natto increased. The findings showed that the two bacteria, B. natto and L. sakei, appear to be a promising probiotic for rotifers in suppressing Vibrio and also in increasing population growth, nutrients retention, enzymes activity and long-term inoculation in rotifers.

    Keywords: Rotifer, Suppression, Vibrio, Enzyme, Brachionus, Probiotic}
  • Y.C. Ying, J.F. Cheng, H. Wang, H.L. Gu, H. Chen, Y. Shao, Y.H. Duan, A.H. Feng, X.L. Fu, H. Quan*, Z.Y. Xu
    Background

    The grading evaluation of atlas based auto-segmentation (ABAS) of organs at risk (OARs) in thorax was studied.

    Materials and Methods

    Forty patients with thoracic cancer were included in this study, and for each thirteen thoracic OARs were delineated by an experienced radiation oncologist. The patients were randomly grouped into the training and the test dataset (20 each). The investigated ABAS strategies included single-atlas (Single), majority voting with 5 atlas matches (MV5) and simultaneous truth and performance level estimation (STAPLE) with 5 atlas matches (ST5). The Dice similarity coefficient (DSC), the difference of the Euclidean distance between centers of mass (ΔCMD), the difference of volume (ΔV), maximum Hausdorff distance (MHD) and average Hausdorff distance (AHD) between auto-segmented and manual contours were calculated.

    Results

    Most of the index values (33/65) of ST5 were optimal. There were differences in the grading results for the five indexes. With DSC, five, four and four OARs were graded into Level 3, Level 2 and Level 1, respectively. The mean DSC values ranged from 0.88 to 0.96, from 0.73 to 0.79, and from 0.53 to 0.62 for the Level 3, Level 2 and Level 1, respectively.

    Conclusion

    Grading evaluation of ABAS of thoracic OARs based on the DSC proved to be feasible and relatively more reliable. The thoracic OARs auto-segmentation was divided into three levels based on the DSC. Level 3 OARs can be auto-segmented, Level 2 OARs delineations need to be manually modified after the auto-segmentation, and Level 1 OARs are not recommended for the auto-segmentation.

    Keywords: Atlas based auto-segmentation, grading evaluation, thorax, organs at risk}
  • H. Wang, H. Chen, Y. Shao, J.M. Wang, J.D. Guo, X.W. Cai, X.I. Fu, Z.Y. Xu*
    Background

    The pattern of interfractional tumor changes during limited disease small-cell lung cancer (LD-SCLC) radiotherapy is not clear, The study was to evaluate tumor changes based on interfractional CBCT images and it’s impact on dosimetry.

    Material and Method

    We analyzed tumor changes and it’s dosimetry impact for 30 LD-SCLC patients who were treated with concurrent chemoradiotherapy(cCRT). CBCT images were acquired for each patient every five fractions before each treatment. The grass tumor volume(GTV) and total lung were adapted to create the GTVn and total lungn based on CBCTn. Dose was recalculated for every CBCT fraction. The impact on target dose coverage and lung sparing was also evaluated while relevant tissue's CT density correction was done on plan CT combined with tumor changes adapted by fraction’s CBCT images.

    Results

    Mean GTV volume of each CBCT fraction reduced,and mean GTV volume of 7th CBCT fraction shrank nearly 10% compared to 1st fraction. The centroid positions of left/right tumors moved towards the right/left direction gradually. Most left/right tumor borders had a trend of rightward/leftward shrinkage. Target dose coverage and lung tissue dose volume increased through fractions. CT image density correction slightly increased the target dose coverage and lung tissue dose volume.

    Conclusion

    Tumor shrinkage was seen for LD-SCLC patients, it’s related to the tumor's initial volume and location. It is appropriate that most LD-SCLC patients should be intervened at 21st radiotherapy fraction.

    Keywords: Tumor shrinkage, interfractional cone beam CT, dosimetry, limited disease (LD) small-cell lung cancer}
  • Z. Zhang, H. Wang, J. Ma*, X. Ling

    In textile printing and dyeing industry, a novel type of separator called high gravity rotary gas-liquid separator (HGRGS) is designed, which includes a rotary drum with multi-layer fins and an impeller. First, the structure and separation principle of HGRGS are introduced in this paper. Then, the flow field and separation efficiency are studied by CFD techniques. To ensure the accuracy of the numerical simulation, the results are verified by the available experimental data. Compared with the typical cyclone, the maximum pressure drop reduction rate in HGRGS is 64.7% when the gas enters at 10 m/s. Besides, for droplets less than 5 μm, the separation performance in HGRGS is more efficient and it will be greatly improved by 30% for 1 μm droplets. The numerical results also show that the tangential velocity inside the rotary drum is linear with the radius and the higher the rotating speed, the greater the tangential velocity. Moreover, the maximum tangential velocity between the forced and quasi-free vortex has moved to the vicinity of the outer wall, which is beneficial for droplets to move outward. Additionally, the droplets in HGRGS can be captured with enough residence time owing to the lower axial velocity than that in a typical cyclone.

    Keywords: High gravity, Gas-liquid separator, Rotary drum, Pressure drop, Separation efficiency, Simulation}
  • D. Hwang, K. Ahn*, Y. Yoon
    An experimental study has been carried out to investigate the effects of inlet velocity, equivalence ratio, and acoustic forcing on flame lengths and flame center lengths in a dump combustor. A premixed gas of ethylene and air was supplied to a combustor through an inlet section and an acoustic driver was used to generate acoustic forcing to simulate unstable combustion. By changing these parameters, combustion tests were performed and flame images were taken using an ICCD camera with a bandpass filter corresponding to a CH* chemiluminescence band. Flame lengths/flame center lengths were obtained from the flame images and were analyzed with respect to dimensional parameters. For a more general finding, the flame length and flame center length were normalized by the inlet width. The dimensional parameters were also replaced with nondimensional parameters such as the Reynolds number, Strouhal number, Damköhler number, and normalized inlet velocity fluctuation, since dimensional parameters have a complex influence on these non-dimensional parameters. The normalized flame lengths and flame center lengths could be expressed well as a function of the non-dimensional parameters. It was found that an increase in the Reynolds number and a decrease in the Strouhal number, Damköhler number and normalized inlet velocity fluctuation caused the flame length/flame center length to become greater.
    Keywords: Flame length, Flame center length, Dump combustor, Combustion instability, Turbulent vortex flame}
  • Mohammad Taher Rajabi, Konstantinos Papageorgiou, Mehryar Taban, Catherine J. Hwang, Robert A. Goldberg
    PurposeTo present the qualitative and quantitative ultrasonographic findings of lower eyelid compartments in patients with chronic thyroid associated ophthalmopathy (TAO) compared to normal subjects.
    MethodsIn a prospective study, dynamic and static ultrasonographic investigation, applying high resolution (15 MHz) ultrasound was performed to assess the lower eyelid, in 15 TAO patients that were in chronic phase and 10 normal subjects. The thickness and echogenisity of dermis, orbicular oculi muscle, lower eyelid retractor muscle, lower eyelid fat pads, and their qualitative relationships during vertical excursion of the globe were evaluated in static and dynamic investigation. Correlation of ultrasonic and clinical findings was evaluated.
    ResultsThe mean age of the patients was 41.82 ± 7.4 years, and the controls were age-matched (mean age, 42.8 ± 5.6 years). Mean proptosis of the involved eyes was 3.3 mm, and mean lower lid retraction was 2.4 mm in chronic TAO group. Pattern of fat motion was blocky in chronic TAO patients compared to normal jelly motion of the fat in normal cases. In analyzing the range of motion, the difference was significant in the motion of both superficial and deep fat pockets between the two groups (P ConclusionDevelopment of a series of static and dynamic changes in ultrasound is related to the clinical findings in chronic phase of TAO. The limitation of motion and fibrotic changes of lower eyelid fat pads were more detectable in cases with a more severe proptosis and lower lid retraction. It is considered that ultrasound findings can be a representative of the severity of involvement in the chronic phase of the TAO.
    Keywords: Thyroid associated ophthalmopathy, Lower lid retraction, Ultrasonography, Lower lid fat pads}
  • K. C. Hsu, S. R. Hwang, K. L. Tseng*
    In this paperý, ýwe shall establish some extended Simpson-type inequalitiesý ýfor differentiable convex functions and differentiable concave functionsý ýwhich are connected with Hermite-Hadamard inequalityý. ýSome error estimatesý ýfor the midpointý, ýtrapezoidal and Simpson formula are also givený.
    Keywords: Hermite-Hadamard inequalityý, ýSimpson inequalityý, ýmidpointý ýinequalityý, ýtrapezoid inequalityý, ýconvex functioný, ýconcave functionsý, ýspecial meansý, ýquadrature rulesý}
  • Investigating Reworks in Green Building Construction Projects: Magnitude, Influential Factors, and Solutions
    B. G. Hwang, M. Shan, E. K. Tan
    Rework is a stubborn issue in the construction industry, and it has been drawing considerable attention from the industry and academia over the past decades. However, so far, little effort has been made to investigate reworks in green building construction projects. This study aims to assess the status quo of rework in green building construction projects in Singapore, identify and evaluate the rework factors in green building construction projects, compare their criticalities with those in the conventional counterparts, and propose a set of feasible solutions. To achieve these aims, a questionnaire survey was administered, and data collected from 30 different construction companies were analyzed. Results showed that, compared to conventional building construction projects, green building construction projects tended to have a lower incidence of rework, but suffered more from the rework’s adverse impacts in terms of cost overrun and schedule delay. Results also showed that the top four most critical rework factors in green building construction projects were “owner change”, “design change”, “design error/omission” and “contractor’s error/omission”. In addition, this study proposed five practical solutions that can help curb reworks in green building construction projects. This study contributes to the body of knowledge by examining the rework problem in green building construction projects. Meanwhile, this study contributes to the industry by providing the practitioners with an in-depth understanding of rework in green building construction projects. The specific solutions proposed by this study can also offer the industry practitioners direct help in reducing works in such projects.
    Keywords: Rework, Rework factors, Solutions, Green building construction projects}
نمایش عناوین بیشتر...
بدانید!
  • در این صفحه نام مورد نظر در اسامی نویسندگان مقالات جستجو می‌شود. ممکن است نتایج شامل مطالب نویسندگان هم نام و حتی در رشته‌های مختلف باشد.
  • همه مقالات ترجمه فارسی یا انگلیسی ندارند پس ممکن است مقالاتی باشند که نام نویسنده مورد نظر شما به صورت معادل فارسی یا انگلیسی آن درج شده باشد. در صفحه جستجوی پیشرفته می‌توانید همزمان نام فارسی و انگلیسی نویسنده را درج نمایید.
  • در صورتی که می‌خواهید جستجو را با شرایط متفاوت تکرار کنید به صفحه جستجوی پیشرفته مطالب نشریات مراجعه کنید.
درخواست پشتیبانی - گزارش اشکال