鼻声反射仪联合鼻阻力计在鼻中隔偏曲鼻通气功能客观评估中的应用

目的探讨鼻声反射仪联合鼻阻力计在鼻中隔偏曲鼻通气功能客观评估中的应用价值。方法将鼻中隔偏曲患者40例作为试验组,同期选择健康体检人群40例作为对照组,两组人群均采用鼻声反射仪、四相鼻阻力计测量鼻通气功能。结果试验组的V2-5、V5-7容积显著低于对照组,试验组的鼻腔距前鼻孔的距离(MD)显著高于对照组(P<0.05);试验组的吸气有效阻力(Reffin)、呼气有效阻力(Reffex)、吸气顶点阻力(VRin)和呼气顶点阻力(VRex)均显著高于对照组(P<0.05)。结论鼻声反射仪联合鼻阻力计可有效评估鼻中隔偏曲鼻腔容器及气道受阻情况,是一种客观评价通气功能的有效方式。

鼻阻力计评估鼻中隔偏曲矫正术后疗效的观察与护理

[目的]探讨鼻阻力计评估鼻中隔偏曲矫正术后疗效的观察与护理。[方法]对60例鼻中隔偏曲病人行鼻中隔偏曲矫正术,采用鼻阻力计结合视觉模拟评分法(VAS)评估鼻中隔偏曲矫正术手术效果。[结果]与术前比较,鼻中隔偏曲病人在术后12h鼻气道阻力及VAS评分均降低(P<0.05)。[结论]采用鼻阻力计能较好评估鼻中隔偏曲矫正术前后鼻腔气道阻力的改变情况,同时采用VAS对鼻中隔偏曲病人进行评分,能准确、客观地评估鼻中隔偏曲矫正术的疗效。

鼻声反射仪联合鼻阻力计在维吾尔族鼻中隔偏曲鼻通气功能评估中的应用

目的研究鼻声反射仪联合鼻阻力计在维吾尔族患者鼻中隔偏曲鼻通气功能评估中的应用方法及其效果。方法选取2016年1月至12月接收治疗的鼻中隔偏曲患者88例,根据民族分为维吾尔族组45例和汉族组43例。两组患者均给予鼻声反射仪联合鼻阻力计检测,观察比较两组患者鼻腔总鼻阻力(RM)值(R总)、阻塞侧鼻腔RM值(R阻塞)与非阻塞侧鼻腔RM值(R非阻塞),观察比较两组患者双侧鼻腔第一狭窄面积(Min1)、第二狭窄面积(Min2)、最小截面积(MCA)和最小截面积所处位置到前鼻孔的距离(DCAN),观察比较两组患者双侧0～2 cm(V0～2)、2～5 cm(V2～5)、0～5 cm(V0～5)鼻腔容积。结果维吾尔族患者R总[(1. 43±0. 41) Pa·cm^(-3)·s^(-1)]、R阻塞[(6. 38±1. 49) Pa·cm^(-3)·s^(-1)]、R非阻塞[(1. 97±0. 45) Pa·cm^(-3)·s^(-1)]均明显大于汉族患者[(0. 36±0. 10) Pa·cm^(-3)·s^(-1)、(1. 42±0. 35) Pa·cm^(-3)·s^(-1)、(0. 54±0. 13) Pa·cm^(-3)·s^(-1),P均<0. 05];阻塞侧与非阻塞侧Min1、Min2、MCA、DCAN在两组间比较差异均无统计学意义(P均> 0. 05),其中71例(80. 68%)的患者双侧鼻腔MCA都出现在Min1,17例(19. 32%)患者双侧鼻腔MCA出现在Min2(其中维吾尔族组阻塞侧5例,非阻塞侧3例;汉族组非阻塞侧9例,阻塞侧0例)。阻塞侧鼻腔容积中,V0～2、V2～5及V0～5在两组患者间比较差异均无统计学意义(P均> 0. 05)。非阻塞侧鼻腔容积中,V0～2在两组患者间比较差异无统计学意义(P> 0. 05)。维吾尔族患者V2～5[(5. 26±1. 47) cm-3]、V0～5[(7. 08±1. 58) cm-3]均大于汉族患者[(4. 32±1. 13) cm-3、(6. 16±1. 91) cm-3,P <0. 01,P <0. 05]。两组患者双侧鼻腔总容积比较无统计学差异(P> 0. 05),汉族组为(10. 95±2. 73) cm-3,维吾尔族组为(11. 27±2. 69) cm-3。结论鼻声反射仪联合鼻阻力计可有效检测鼻中隔偏曲患者的鼻通气功能情况,相对来说,维吾尔族患者的偏曲程度更为严重。

Calculation mode of side friction for large open caisson

To overcome the problems in design methodologies and construction control measures for the large open caisson, systematic research was conducted on the side friction calculation mode of the large open caisson. Based on the field monitoring data of lateral soil pressure on the side wall of the open caisson for the southern anchorage of the Maanshan Yangtze River Highway Bridge, the statistical result of the side friction under different buried depths of the cutting edge of the open caisson was back-analyzed; and the side friction distribution of the large open caisson was underlined. The analysis results indicate that when the buried depth of the cutting edge is smaller than a certain depth H0, the side friction linearly increases with the increase in the buffed depth. However, as the buffed depth of the cutting edge is larger than H0, the side friction shows a distribution with small at both ends and large in the middle. The top of the distribution can be regarded as a linear curve, while the bottom as a hyperbolic curve. As the buffed depth of cutting edge increases continuously, the peak value of the side friction linearly increases and the location of the peak value gradually moves down. Based on the aforementioned conclusions, a revised calculation mode of the large open caisson is presented. Then, the calculated results are compared with the field monitoring data, which verifies the feasibility of the proposed revised calculation mode.

4900m^3/h空分运行工况异常原因分析及处理

介绍杭钢气体厂4900 m3/h空分引起运行工况异常的原因过冷器污氮、纯氮通道堵塞,对空分设备正常运行带来影响。文章简介了该空分设备的工艺流程,详细叙述了发生运行工况异常的原因,阐述了处理措施及效果检查。

Impedance force control for position controlled robotic manipulators under the constraint of unknown environments

A force control strategy for position controlled robotic manipulators is presented. On line force feedback data are employed to estimate the local shape of the unknown constraint. The estimated vectors are used to generate the virtual reference trajectory for the target impedance model that is driven by the force error to produce command position. By following the command position trajectory the robotic manipulator can follow the unknown constraint surface while keeping an acceptable force error in a manner depicted by the target impedance model. Computer simulation on a 3 linked planar manipulator and experimental studies on an Adept 3, an SCARA type robotic manipulator, are conducted to verify the force tracking capability of the proposed control strategy.

Discussion of Grid Generation for Catamaran Resistance Calculation

In order to get some useful parameters for grid generation of catamaran, the CFD software FLUENT is used to investigate the main effects of grid generation on flow field calculation. The influences of some elements are investigated with a series of calculations in the present paper, and some alteratives are proposed. The proposed alteratives based on the analysis of the effects are used for a catamaran resistance calculation, comparisons of the calculated results with experimental data show good agreement. It shows that the research result of this paver is useful for the numerical calculation of catamaran.

Simulation of Hydrodynamic Performance of Drag and Double Reverse Propeller Podded Propulsors

The unsteady performance of drag and double reverse propeller podded propulsors in open water was numerically simulated using a computational fluid dynamics （CFD） method. A moving mesh method was used to more realistically simulate propulsor working conditions, and the thrust, torque, and lateral force coefficients of both propulsors were compared and analyzed. Forces acting on different parts of the propulsors along with the flow field distribution of steady and unsteady results at different advance coefficients were compared. Moreover, the change of the lateral force and the difference between the abovementioned two methods were mainly analyzed. It was shown that the thrust and torque results of both methods were similar, with the lateral force results having the highest deviation

A Havelock Source Panel Method for Near-surface Submarines

A panel method is described for calculating potential flow around near-surface submarines. The method uses Havelock sources which automatically satisfy the linearized free-surface boundary condition. Outputs from the method include pressure field, pressure drag, wave resistance, vertical force, trim moment and wave pattern. Comparisons are made with model tests for wave resistance of Series 58 and DARPA SUBOFF hulls, as well as with wave resistance, lift force and trim moment of three length-to-diameter variants of the DSTO Joubert submarine hull. It is found that the Havelock source panel method is capable of determining with reasonable accuracy wave resistance, vertical force and trim moment for submarine hulls. Further experimental data are required in order to assess the accuracy of the method for pressure field and wave pattern prediction. The method is implemented in the computer code“HullWave”and offers potential advantages over RANS-CFD codes in terms of speed, simplicity and robustness.

A simplified approach for negative skin friction calculation of special-shaped pile considering pile-soil interaction under surcharge

A simplified approach was proposed to analyze the negative skin friction calculation of special-shaped pile considering pile-soil interaction under surcharge. Based on the concentric cylinder shearing theory, considering the changes of pile shape(such as, taper angle and diameters of pile base, etc.), the load-transfer of special-shaped pile was built. The accuracy of the developed simplified approach was verified by numerical simulation model with the same condition. Then, the influence factors, such as, taper angles, the diameter of pile base, surcharge, and pile-soil interface parameters were analyzed and discussed. The results show that the developed simplified approach can calculate NSF of special-shaped pile under surcharge effectively. A limited parametric study indicates that in many practical situations special-shaped piles(such as belled wedge pile shown in this work) offer a design option that is more economical than traditional uniform cross-section piles.

Evaluation of asphalt-aggregate adhesion using surface free energy theory

In order to take a precise and objective evaluation on asphalt-aggregate adhesion, this paper analyzed the function at asphalt- aggregate interface using surface free energy theory. Two asphalts and two aggregates were selected and their surface free energy parameters, FLW, F and F-, were measured by the Wilhelmy plate method and the column wicking technique, respectively. Then, the resistance to moisture damage of asphalt mixture were predicted using calculated asphalt-aggregate adhesive bond energy and asphalt cohesive bond energy. The results show that moisture damage is a thermodynamically favorable phenomenon. Asphalt with a great acid-base polar component and a low Lifshitz-van der Waals apolar component always exhibits perfect cohesion.

Estimation of Added Resistance for Large Blunt Ship in Waves

Under the background of the energy saving and emission reduction, more and more attention has been placed on investigating the energy efficiency of ships. The added resistance has been noted for being crucial in predicting the decrease of speed on a ship operating at sea. Furthermore, it is also significant to investigate the added resistance for a ship functioning in short waves of large modern ships. The researcher presents an estimation formula for the calculation of an added resistance study in short waves derived from the reflection law. An improved method has been proposed to calculate the added resistance due to ship motions, which applies the radiated energy theory along with the strip method. This procedure is based on an extended integral equation （EIE） method, which was used for solving the hydrodynamic coefficients without effects of the irregular frequency. Next, a combined method was recommended for the estimation of added resistance for a ship in the whole wave length range. The comparison data with other experiments indicate the method presented in the paper provides satisfactory results for large blunt ship.

Development of Cubic Bezier Curve and Curve-Plane Intersection Method for Parametric Submarine Hull Form Design to Optimize Hull Resistance Using CFD

Optimization analysis and computational fluid dynamics （CFDs） have been applied simultaneously, in which a parametric model plays an important role in finding the optimal solution. However, it is difficult to create a parametric model for a complex shape with irregular curves, such as a submarine hull form. In this study, the cubic Bezier curve and curve-plane intersection method are used to generate a solid model of a parametric submarine hull form taking three input parameters into account： nose radius, tail radius, and length-height hull ratio （L/H）. Application program interface （API） scripting is also used to write code in the ANSYS DesignModeler. The results show that the submarine shape can be generated with some variation of the input parameters. An example is given that shows how the proposed method can be applied successfully to a hull resistance optimization case. The parametric design of the middle submarine type was chosen to be modified. First, the original submarine model was analyzed, in advance, using CFD. Then, using the response surface graph, some candidate optimal designs with a minimum hull resistance coefficient were obtained. Further, the optimization method in goal-driven optimization （GDO） was implemented to find the submarine hull form with the minimum hull resistance coefficient （Ct）. The minimum C, was obtained. The calculated difference in （7, values between the initial submarine and the optimum submarine is around 0.26%, with the C, of the initial submarine and the optimum submarine being 0.001 508 26 and 0.001 504 29, respectively. The results show that the optimum submarine hull form shows a higher nose radius （rn） and higher L/H than those of the initial submarine shape, while the radius of the tail （r1） is smaller than that of the initial shape.

Optimal design of FRMSM to decrease detent force

An optimal configuration of the flux-reversal linear synchronous motor (FRLSM) with the optimal number of attachment permanent magnets (PMs) was presented. The optimal model of 2 000 N was designed to reduce the detent force by redesigning the air-gap structure and skewing. The design parameters,mover PMs and stator core,were selected for optimal design by DOE. The thrust and the detent force of the designed optimal models were compared by finite element analysis (FEA). As a result,the thrust of the optimal model is slightly decreased by 1.97% compared with the basic model,and the detent force of the optimal model is greatly decreased by 88.47% compared with the basic model.

Test Series Results of Varying Yaw and Roll Angles of Trimaran Amas

This paper illustrates the reasons behind the research strategy that has led to a new generation of trimaran hulls by minimizing the hull＇s drag-design approach. The objective of this study was to search for the optimal side-hull yaw and roll angle to minimize induced drag of trimarans a^d so to investigate the differences in the performance results of a trimaran hull. Specifically, this research has been based on a critical analysis of the diversity of ama yaw and roll angles and outriggers positioning. Then, the paper will be comparing the results of the test series of the yaw and roll angles of trimaran areas. Design and towing tank test of a scaled trimaran model will be illustrated and compared along with some key and relevant results. The term ＂ama＂ is a word in the Polynesian and Micronesian languages to describe the outrigger part of a canoe to provide stability.

An Innovative Hullform Design Technique for Low Carbon Shipping

Combining modem Computational Fluid Dynamics （CFD） evaluator with optimization method, a new approach of hullform design for low carbon shipping is presented. Using the approach, the designers may find the minimum of some user-defined objective functions under constrains. An example of the approach application for a surface combatant hull optimization is demonstrated. In the procedure, the Particle Swarm Optimization （PSO） algorithm is adopted for exploring the design space, and the Bezier patch method is chosen to automatically modify the geometry of bulb. The total resistance is assessed by RANS solvers. It＇s shown that the total resistance coefficient of the optimized design is reduced by about 6.6% comparing with the original design. The given combatant design optimization example demonstrates the practicability and superiority of the proposed approach for low carbon shipping.

Proof of Concept MFD Optimization of the Aftbody Geometry of Axisymmetric Slender Body Based on Wave Drag Considerations

A comprehensive, universally valid, elegant and yet simple method to design slender axisymmetric body of minimum wave drag in transonic and supersonic flows is developed. Computational aerodynamics is also used as a tool for numerical experiments in gaining physical understanding of the drag mechanism due to the geometry of the aftbody, such as the correlation between wave drag and wave distribution of the aftbody geometry. The method utilizes MFD （modified feasible direction） based optimization program, along with the linear slender body aerodynamics, for its elegance and generic optimization convenience. The efforts are focused on inviscid flow. A practical method of reducing the wave drag of a given body is developed for both bodies with pointed end and with base area, using shock wave generator at a particular location on the aftbody. The results show that the MFD optimization program can be effectively utilized in an aerodynamic optimization problem.

A B-Spline Method Used to Calculate Added Resistance in Waves

Making an exact computation of added resistance in sea waves is of high interest due to the economic effects relating to ship design and operation. In this paper, a B-spline based method is developed for computation of added resistance. Based on the potential flow assumption, the velocity potential is computed using Green＇s formula. The Kochin function is applied to compute added resistance using Maruo＇s far-field method, the body surface is described by a B-spline curve and potentials and normal derivation of potentials are also described by B-spline basis functions and B-spline derivations. A collocation approach is applied for numerical computation, and integral equations are then evaluated by applying Gauss–Legendre quadrature. Computations are performed for a spheroid and different hull forms; results are validated by a comparison with experimental results. All results obtained with the present method show good agreement with experimental results.

New method of designing anti-slide piles——the strength reduction FEM

At present,the thrust of an anti-slide pile can be worked out with some calculation methods. However,the resistance in front of the pile,the distributions of resistance and thrust,and appropriate pile length cannot be easily obtained. In this paper,the authors applied the strength-reduction finite element method (FEM) to several design cases of anti-slide piles. Using this method,it is possible to take the pile-soil interactions into consideration,obtain reasonable resistance in front of pile and the distributions of thrust and resistance,and reasonable lengths of anti-slide piles. In particular,the thrust and resistance imposed on embedded anti-slide piles can be calculated and composite anti-slide pile structures such as anchored piles and braced piles can be optimized. It is proved through the calculation examples that this method is more reliable and economical in the design of anti-slide pile.

A Practical Hull Form Design of Ferry Using Hybrid Scheme Method and Performing Experiment

Prediction of ship performance in preliminary ship design is an important consideration. It could guarantee ship in safe and comfort. However, many design works did not involve simultaneously ship performances predictions in preliminary design. Moreover, ship designers sometimes modified a ship form to obtain proper design without ship performance consideration. Therefore, this study concerns on predictions of total resistance and added wave resistance of a ferry using a hybrid particle-grid method and then its motions response after modifying bow and stern parts by conducting experiment. Research results show total resistance and added wave resistance have a significant different, therefore, it would be an important consideration in determining ship powering in preliminary ship design. The non-dimensional added wave resistance increases in increasing wave length from λ/Lpp = 0.5 to 1.0 and it decreases after L/λ = 1.0. In addition, it tends to decrease caused by increasing ship speed. The comparison of averaged heave and pitch amplitudes between basic forms after modifying bow and stem parts is quiet similar. However, the rolling amplitude of the modified form is significantly higher comparing with the basic form. We conclude that a ship could be design in preliminary design take into account performances predictions by using numerical method and experimental work.