Correction of complex three-dimensional deformities at the proximal femur using indirect reduction with angle blade plate and patient-specific instruments: a technical note

Background Corrective osteotomies for complex proximal femoral deformities can be challenging; wherefore, subsidies in preoperative planning and during surgical procedures are considered helpful. Three-dimensional (3D) planning and patient-specific instruments (PSI) are already established in different orthopedic procedures. This study gives an overview on this technique at the proximal femur and proposes a new indirect reduction technique using an angle blade plate. Methods Using computed tomography (CT) data, 3D models are generated serving for the preoperative 3D planning. Different guides are used for registration of the planning to the intraoperative situation and to perform the desired osteotomies with the following reduction task. A new valuable tool to perform the correction is the use of a combined osteotomy and implant-positioning guide, with indirect deformity reduction over an angle blade plate. Results An overview of the advantages of 3D planning and the use of PSI in complex corrective osteotomies at the proximal femur is provided. Furthermore, a new technique with indirect deformity reduction over an angle blade plate is introduced. Conclusion Using 3D planning and PSI for complex corrective osteotomies at the proximal femur can be a useful tool in understanding the individual deformity and performing the aimed deformity reduction. The indirect reduction over the implant is a simple and valuable tool in achieving the desired correction, and concurrently, surgical exposure can be limited to a subvastus approach.

A Mathematical Model for Windmilling of a Turbojet Engine

The transient windmilling characteristic of a modern turbojet engine under different flight conditions and altitudes is obtained with numerous tests conducted at an Altitude Test Facility (ATF). A simple and practical mathematical model for predicting the transient and steady-state rotational speed of a simple turbojet engine in flight has been developed. The method is derived from Froude’s momentum theory or disk actuator theory and implemented to a turbojet engine. A correction factor is introduced to match with test results of KTJ-3200 being indigenously developed by Kale R&D Inc. The present model’s predictions are compared with the test data of Microturbo TRI 60 engine and KTJ-3200 engine. The estimation of the present windmilling model fits very well with test results of two different engines within an error band of ±1.2% for various atmosphere conditions depending on flight speed, altitudes and temperature. The present model is compared with loss modeling windmilling estimation methods described in literature which requires large amount of inputs as blade angle, blade pitch and component efficiencies. The comparison with the available windmilling model at literature shows that both models capture the terminal speed estimation very well. However, the model in literature is not able to capture the transient engine speed, which is important for missile applications as the missile can be fired before the engine reaches to terminal speed. The difference between the test data and the available model during transients is up to 50%. The present model matches perfectly with test data even at transients. It is more practical and much simpler than the available windmilling model in the literature to estimate the both transient and terminal windmilling speed of the turbojet engines. The agreement between the present model, KTJ 3200 test data, windmilling method available in the literature and test data of Microturbo TRI 60 is very good for most of the ranges investigated.

PENGARUH JUMLAH DAN SUDUT PEMASANGAN SUDU TERHADAP DAYA TURBIN ANGIN SAVONIUS

The problem in Energy conservation is finding new opportunities for high-efficiency energy generation including wind power generating machines. This study aims to determine the effect of the number and curv angle of blade mounting on the output power of a Savonius type wind turbine. This low speed wind turbine is intended to get energy at the top of a multi-storey building in an urban area. Tests were carried out on a laboratory scale, using savonius wind turbines with a diameter of 400 mm and a height of 500 mm. The driving wind speed of the turbine is set between 1.5 to 8.5 m / s. While the number of blades used is 2 types, namely rotor with three blades and rotor with 4 blades, each of which is tested on 3 different types of curv angle blade. The investigation results are expected to show that the wind tubing from each experiment will give different characteristics. The results showed that there was an increase in efficiency in the savonius turbine with blades. The highest rotation and power occur when the turbine uses 2 blades and -50 curv angle of blade mounting

PENGARUH JUMLAH DAN SUDUT PEMASANGAN SUDU TERHADAP DAYA TURBIN SAVONIUS

The problem in Energy conservation is finding new opportunities for high-efficiency energy generation including wind power generating machines. Aims of this study to determine the effects of blade number and curv angle of blade mounting on the output power of a Savonius type wind turbine. This low speed wind turbine is intended to get energy at the top of a multi-storey building in an urban area. Tests were carried out on a laboratory scale, using savonius wind turbines with 400 mm diameter and 500 mm height. The driving wind speed of the turbine is set between 1.5 to 8.5 m / s. While the number of blades used is 2 types, namely rotor with three blades and rotor with 4 blades, each of which is tested on 3 different types of curv angle blade. The investigation results are expected to show that the wind tubing from each experiment will give different characteristics. This investigation results that there was increasing in efficiency in the savonius turbine with blades. The highest rotation and power occur when the turbine uses 2 blades and -50 curv angle of blade mounting

Role of Valgus Osteotomy and Fixation with Double Angle Blade Plate in the Management of Neglected and Ununited Femoral Neck Fracture

Introduction: Femoral neck fracture non union in young patients is a challenging complication as joint replacement is not readily recommended and hip salvageable procedures are relatively unsatisfactory. Valgus intertrochanteric osteotomy described by Pauwels F is one of the treatment options for management of non union of femoral neck in young patients, which was later reciprocated by other surgeons. Aim: To assess the efficacy of valgus osteotomy and fixation with double angle blade plate in the management of neglected and ununited femoral neck fracture. Materials and Methods: This was a prospective cohort study, which included 30 patients of femoral neck fracture non union in whom intertrochanteric valgus osteotomy was performed and fixed with 120° double angled blade plate. The preoperative and postoperative neck-shaft angle was compared using the paired t-test. A p-value of <0.05 indicated statistically significant result. Results: There were 22 males (73.3%) and 8 females (26.7%). Mean age of patients was 35 years. Delay in presentation ranged from 8 weeks to 58 weeks (mean 24 weeks). By Pauwel’s classification, there were 13 Type II fractures and 17 Type III fractures. Mean follow- up was 18 months (12 to 36 months). The mean preoperative neck- shaft angle of 95° (range 80-110°) increased to 132° (range 120- 140°) after surgery. In all patients, there was improvement in leg length discrepancy after osteotomy. Femoral neck fractures united in 25 patients (83.3%). Conclusion: Valgus osteotomy and fixation with 120° double angle blade plate is a reliable method for treating non union femoral neck fracture in young adults. It provides rigid internal fixation and good results.

Numerical Study on Duct Acoustic Modal and Source Flow Structure of Fan Tones With Leaned and Swept Stator

The present study is focused on the fan tone noise reduction with leaned and swept stator blade. A hybrid URANS/Goldstein’s equations method is used to calculate the unsteady flow and tone noise of a high loaded axial-flow fan. The numerical simulation results show that the fan tone noise will be increased with negative angle lean, while it will be reduced with positive lean angle. The higher the harmonic number, the larger the noise reduction with positive lean angle blade. It is found that when the stator blade sweeps back of 30 degrees, the fan tone noise at the fan inlet can be reduced by 5.5 dB, while the fan tone noise at the fan outlet can be reduced by 9.8dB. It is also found that the combined leaned and swept blade has the largest noise reduction. When the fan stator blade lean angle and sweep angle are both 30 degrees, the fan inlet tone noise can be reduced by 8.5 dB, while the fan outlet tone noise can be reduced by 17dB. The numerical simulation results indicate that the influence of blade lean and sweep on fan mass flow is less than 1% within the scope of this study. The negative lean angle of stator blade can improve the aerodynamic performance, but the positive lean angle of the stator blade will reduce the total pressure ratio and isentropic efficiency of the fan.

MODIFIED LAUTENBACH TECHNIQUE AND EXTERNAL FIXATION AS A TREATMENT FOR INFECTED NON-UNION OF THE SUBTROCHANTER FEMUR: A CASE REPORT

Infected non-union is still a challenging orthopedic case to treat. Up until present day, there is no any established protocol to treat infected non-union of femur. Infection at subtrochanter femur specifically poses extra challenge as aforementioned location is affected by great tension and compression force. In this report, we present a 20-yo woman with infected subtrochanter femur following open reduction internal fixation (ORIF)with angle blade plate (ABP) 95o. One stage surgery was performed involving implant removal, debridement, definite external fixation, and antibiotic delivery using modified Lautenbach technique. Four years after trauma, the patient was capable of independent mobilization without aid. No infection recurrence was found, and Haris Hip Score was 91 (excellent). Based on the result of this case, definite external fixation and modified Lautenbach technique in one stage surgery can be a viable option in treating infected non-union of subtrochanter femur.