scholarly journals Dynamic interaction of military aircraft working on an cement concrete airfield pavement

2020 ◽  
Vol 2020 (2) ◽  
pp. 37-45
Author(s):  
Piotr Nita ◽  
Keyword(s):  
Dynamic Properties ◽  
Geophysical Methods ◽  
Field Tests ◽  
Vibration Measurement ◽  
Test Results ◽  
Military Aircraft ◽  
Cement Concrete ◽  
Dynamic Interactions ◽  
Airport Pavement ◽  
The Impact

The publication presents test results and analysis of the impact of military aircraft on an airport pavement made of pre-stressed panels. Three types of aircraft were used in the experiment, i.e. TS 11 ISKRA aircraft, SU 7 BM aircraft and SU-22 M4 aircraft. In the field tests, geophysical methods were used to measure the dynamic properties of the airport pavement structure. Based on the few vibration measurement methods of this type of construction that can be used, the vibration level of the pavement caused by the aircraft operating on that surface was recorded. The tests were carried out for various levels of aircraft thrust, the degree of harmfulness of the impact of generated vibrations on the pavement by sources of excitement, which were the above-mentioned aircraft, was assessed. Due to the fact that the research was one of the first to be carried out in the country, and such research is rare, there are no publications devoted to this issue also in foreign literature. Therefore, there are no reliable and credible criteria for assessing the impact of vibrations on these constructions. In the assessment of dynamic phenomena, by analogy, assessment methods and criteria related to general construction facilities were used. The most frequently used criteria for assessing dynamic interactions are based on the vibration speed criterion. The publication carried out an impact assessment based on the following criteria: vibrator scale, SWD scale and Zeller scale. Keywords: Aircraft; cement concrete Airfield pavement; Frequency

The Effect of Blade Geometry on Blade Stall Characteristics

2005 ◽  
Vol 127 (4) ◽  
pp. 496-502 ◽  
Author(s):  
R. P. J. O. M. van Rooij ◽  
J. G. Schepers
Keyword(s):  
Correction Term ◽  
Field Tests ◽  
Test Results ◽  
Wind Tunnel Experiments ◽  
Twisted Blade ◽  
The Impact ◽  
2D Airfoil ◽  
Twist Pitch ◽  
Force Characteristics ◽  
Blade Geometry

The effect of rotation has been investigated with emphasis on the impact of blade geometry on the “correction factor” in stall models. The data used came from field tests and wind tunnel experiments performed by the National Renewable Energy Laboratory and were restricted to the steady-state nonyawed conditions. Three blade layouts were available; a blade with constant chord without twist (phase II), a blade with constant chord and twist (phases III and IV), and a tapered blade with twist (phase VI). Effects due to twist and taper were determined from comparison of c n between the different blade layouts. The formulation of the stall model was rewritten so that the measured c n values could be used without reference to 2D airfoil performance. This enabled a direct comparison of the normal force characteristics between the four blade stations of the selected blade configurations. In particular, the correction term f used in stall models for rotational effects was analyzed. The comparison between the test results with a straight and a twisted blade showed that a relation for twist + pitch is required in f . In addition, a dependency offon the angle-of-attack was identified in the measurements and it is recommended that this dependency be incorporated in the stall models.

scholarly journals STUDI PENDAHULUAN BATAS MAKSIMUM KADAR LUMPUR PADA AGREGAT BETON GEOPOLIMER

2019 ◽  
Vol 18 (1) ◽  
Author(s):  
Djedjen Achmad ◽  
Desi Supriyan
Keyword(s):  
Compressive Strength ◽  
Concrete Aggregate ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
Test Results ◽  
Cement Concrete ◽  
Flexural Tensile Strength ◽  
Binder Ratio ◽  
The Impact ◽  
Water Binder Ratio

ABSTRACTHas been researched the impact of mud in aggregate on geopolymer concrete with studies using the cement concrete as a reference. In this study both of concrete are mixed with a variation of mud of 0%, 0.75%, 3% and 5.75% of the combined aggregate weight. Compressive strength of cement concrete is designed with a target of 300 kg / cm2 and geopolymer concrete is made with water binder ratio (w/b) 0.25, Molarity 12 M, the ratio of sodium silicate and sodium hydroxide 1.5. At the age of 3, 7, 14 and 28 day tested of compressive strength, while the spliting test, flexural tensile strength, and modulus of elasticity are tested at 28 days. From the test results, the higher mud content in aggregate , the mechanical properties of the concrete are decreased. Based on testing of compressive strength in cement concrete at 28 days, with a 3% mud content (the content of the reference mud) turns of compressive strength decreased by 77.356%. Of the percentage reduction on the compressive strength of the cement concrete, can be compared to the mud content in geopolymer concrete at 2.04%. Thus the maximum mud on geopolymer concrete aggregate is, for coarse aggregate of 0.68% and a maximum mud content for fine aggregate was 3.4%.Key words : Mud, aggregate, concrete, cement, geopolimer, strengthABSTRAKTelah diteliti dampak kadar lumpur pada agregat untuk beton geopolimer dengan penelitian menggunakan benda uji beton semen sebagai acuan dan beton geopolimer. Dalam penelitian ini ke dua beton tersebut dicampur dengan lumpur gabungan agregat kasar dan agregat halus dengan variasi 0 %, 0.75 %, 3 % dan 5,75 % dari berat agregat gabungan. Beton semen dirancang dengan target kuat tekan 300 kg/cm2 dan beton geopolimer dibuat dengan campuran water binder ratio (w/b) 0.25, Molaritas 12 M, perbandingan sodium silikat dan sodium hidroksida 1.5. Pada umur 3, 7, 14 dan 28 hari dilakukan uji kuat tekan, sedangkan uji kuat tarik belah, uji kuat tarik lentur, dan modulus elastisitas dilakukan pada umur 28 hari. Dari hasil uji terlihat bahwa semakin tinggi kadar lumpur pada agregat, karakteristik mekanis kedua beton tersebut mengalami penurunan. Berdasarkan pengujian kuat tekan pada beton semen umur 28 hari, dengan kadar lumpur 3 % (kadar lumpur referensi) ternyata beton semen mengalami penurunan kuat tekan sebesar 77.356 %. Dari persentase penurunan kuat tekan beton semen tersebut, diplot pada grafik kuat tekan beton geopolimer maka persentase kadar lumpur gabungan yang mengalami penurunan 77.356 % adalah 2.04 %. Dengan demikian kadar lumpur maksimum pada agregat beton geopolimer adalah, untuk agregat kasar sebesar 0.68 % dan kadar lumpur maksimum untuk agregat halus adalah 3.4 %.Kata kunci : Lumpur, agregat, beton, semen, geopolimer, kekuatan

Influence of Polymer Latex on the Interlayer Bonding Performance of Cement Concrete

2014 ◽  
Vol 1065-1069 ◽  
pp. 1780-1783 ◽  
Author(s):  
Tai Xiu Yang ◽  
Jing Zhu
Keyword(s):  
Styrene Butadiene Rubber ◽  
Butadiene Rubber ◽  
Test Results ◽  
Cement Concrete ◽  
Bonding Performance ◽  
Interface Agent ◽  
Bonding Properties ◽  
Interlayer Bonding ◽  
Styrene Butadiene ◽  
The Impact

Adding polymer into cement concrete is used to increase the interlayer bonding performance. The impact of polymer on the interlayer bonding performance was studied by shear strength and tensile strength test. The mix design of the interface agent was optimized through the tensile bending tests of different fiber and polymer dosage. The impact of casting methods and interface agent mix was studied through tests. The test results show that: adding organic fiber and polymer into cement concrete could significantly increase the interlayer bond strength. The interface agent of SBR (styrene-butadiene rubber) latex modified cement paste has better tensile bonding properties. When the ratio of cement to DB-1 latex is 3:2, it will effectively increase the interlayer bonding performance of cement concrete.

scholarly journals Research on Load Characteristics of Axle-Box Bearing Raceway under Wheel-Rail Excitation

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Xiaokang Liao ◽  
Cai Yi ◽  
Fengyu Ou ◽  
Yi Zhang ◽  
Zili Chen ◽  
...  
Keyword(s):  
Working Conditions ◽  
High Speed ◽  
Dynamic Performance ◽  
Field Tests ◽  
Contact Load ◽  
Dynamic Interactions ◽  
Load Characteristics ◽  
Track Irregularity ◽  
The Impact ◽  
Excitation Conditions

With the increasing speed of high-speed trains, the service conditions of axle-box bearing system worsen, and meanwhile, the dynamic performance of the axle-box bearing directly affects the operational safety. However, the dynamic interactions of the axle-box bearing in the traditional vehicle-track system are often ignored. In this paper, a vehicle-track coupling dynamic model considering axle-box bearing has been built, and the effectiveness of the model is proved by field tests. Dynamic performance of the axle-box bearing has been analyzed and discussed through numerical simulations under different working conditions. Comparing the roller-raceway contact load characteristics under different working conditions, results show that the peak values of roller-outer raceway contact load with wheel-polygonal excitation are basically the same with those without wheel-rail excitation. However, most of the peak values of roller-outer raceway contact force under track irregularity and comprehensive excitation conditions are far greater than those under wheel-polygonal excitation and no wheel-rail excitation conditions, which indicates that the impact of track irregularity on the contact load is dominant.

scholarly journals The Impact of Time Delays for Power Hardware-in-the-Loop Investigations

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3154
Author(s):  
Jana Ihrens ◽  
Stefan Möws ◽  
Lennard Wilkening ◽  
Thorsten A. Kern ◽  
Christian Becker
Keyword(s):  
Time Delays ◽  
Field Tests ◽  
General Concept ◽  
Hardware In The Loop ◽  
Dynamic Interactions ◽  
Case Examples ◽  
System A ◽  
Grid Interface ◽  
The Impact ◽  
Critical Process

Power hardware-in-the-loop (PHiL) simulations provide a powerful environment in the critical process of testing new components and controllers. In this work, we aim to explain the impact of time delays in a PHiL setup and recommend how to consider them in different investigations. The general concept of PHiL, with its necessary components, is explained and the benefits compared to pure simulation and implemented field tests are presented. An example for a flexible PHiL environment is shown in form of the Power Hardware-in-the-Loop Simulation Laboratory (PHiLsLab) at TU Hamburg. In the PHiLsLab, different hardware components are used as the simulator to provide a grid interface via an amplifier system, a real-time simulator by OPAL-RT, a programmable logic controller by Bachmann, and an M-DUINO microcontroller. Benefits and limitations of the different simulators are shown using case examples of conducted investigations. Essentially, all platforms prove to be appropriate and sufficiently powerful simulators, if the time constants and complexity of the investigated case fit the simulator performance. The communication interfaces used between simulator and amplifier system differ in communication speed and delay; therefore, they have to be considered to determine the level of dynamic interactions between the simulated rest of system and the hardware under test.

scholarly journals The Influence of the Aircraft Operating Fluids on the Mechanical Parameters of the Airport Surface Concrete

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3081 ◽  
Author(s):  
Wojciech Żebrowski ◽  
Paweł Wolka ◽  
Marzena Kurpinska
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Mechanical Parameters ◽  
Cement Concrete ◽  
Concrete Properties ◽  
Airport Pavement ◽  
Compressive Strength Of Concrete ◽  
Student’S T ◽  
The Impact ◽  
Student’S T Test

The authors of the article assessed the impact of operating fluids used to service aircraft on changing mechanical parameters of cement concrete intended for airport pavement. The research concerned concrete designed with the use of CEM I 42.5N LH NA low-alkali cement, broken granite aggregate, fine washed aggregate, and admixtures. The analysis included the assessment of changes in differences in endurance parameters over various research periods of up to 140 days. The obtained results allowed to carry out statistical analysis using the student’s T-test. Research has shown a significant impact of operational fluids used in aircraft on the surface concrete properties of the airport. A reduction in the compressive strength of concrete exposed to one of the tested operating liquid to a reduction of 7.2% was observed over a period of 140 days, while there was no significant impact of operating fluids on tensile strength at splitting.

scholarly journals Estimating the Impact of Texture Depth on the Roughness of Cement Concrete Airfield Pavements

2019 ◽  
Vol 49 (2) ◽  
pp. 341-362 ◽  
Author(s):  
Mariusz Wesołowski ◽  
Krzysztof Blacha
Keyword(s):  
Coefficient Of Friction ◽  
Contact Surface ◽  
Field Tests ◽  
Surface Friction ◽  
Skid Resistance ◽  
Cement Concrete ◽  
Friction Characteristics ◽  
The Coefficient Of Friction ◽  
The Impact

Abstract Appropriate skid resistance properties of airfield pavements are extremely important in terms of the safety of air operations. Their evaluation is not limited to the measurements of the coefficient of friction, which determines the roughness of a pavement, but also involves measuring the depth of the pavement texture (micro- and macrotexture), which is a component of the tire-pavement contact surface friction characteristics. It should be stressed that the current aviation documents do not contain a strict interconnection between the texture depth parameter and airfield pavement coefficient of friction criteria. Based on the result population gathered in the course of the field tests, the authors plan to determine the impact of texture on the roughness of airfield pavements.

Model estimates of the results of diabetes patients using modern glucometers with tri-color technology for displaying test results

2019 ◽  
pp. 81-89
Author(s):  
Larisa Dmitrievna Popovich ◽  
Svetlana Valentinovna Svetlichnaya ◽  
Aleksandr Alekseevich Moiseev
Keyword(s):  
Diabetes Mellitus ◽  
Type 2 Diabetes ◽  
Type 1 Diabetes ◽  
Economic Benefits ◽  
Test Results ◽  
Self Monitoring ◽  
Patients With Diabetes ◽  
The Impact

Diabetes – a disease in which the effect of the treatment substantially depends on the patient. Known a study showed that the use of glucometers with the technology of three-color display of test results facilitates self-monitoring of blood sugar and leads to a decrease in glycated hemoglobin (HbAlc). Purpose of the study: to modeling the impact of using of a glucometer with a color-coded display on the clinical outcomes of diabetes mellitus and calculating, the potential economic benefits of reducing the hospitalization rate of patients with diabetes. Material and methods. Based on data from two studies (O. Schnell et al. and M. Baxter et al.) simulation of the reduction in the number of complications with the use of a glucometer with a color indication. In a study by O. Schnell et al. a decrease of HbA1c by 0.69 percent is shown when using the considered type of glucometers, which was the basis of the model. Results. In the model, the use of a glucometer with a color-coded display for type 1 diabetes led to a decrease in the total number of complications by 9.2 thousand over 5 years per a cohort of 40 thousand patients with different initial levels of HbA1c. In a cohort of 40 thousand patients with type 2 diabetes, the simulated number of prevented complications was 1.7 thousand over 5 years. When extrapolating these data to all patients with diabetes included in the federal register of diabetes mellitus (FRD), the number of prevented complications was 55.4 thousand cases for type 1 diabetes and 67.1 thousand cases for type 2 diabetes. The possible economic effect from the use of the device by all patients with a diagnosis of diabetes, which are included in the FRD, estimated at 1.5 billion rubles for a cohort of patients with type 1 diabetes and 5.3 billion rubles for patients with type 2 diabetes. Conclusion. Improving the effectiveness of self-monitoring, which is the result of the use of glucometers with color indicators, can potentially significantly reduce the incidence of complications in diabetes and thereby provide significant economic benefits to society.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

The impact of humic and fulvic acids on the dynamic properties of liposome membranes: the ESR method

2013 ◽  
Vol 24 (2) ◽  
pp. 106-112 ◽  
Author(s):  
Dariusz Man ◽  
Izabella Pisarek ◽  
Michał Braczkowski ◽  
Barbara Pytel ◽  
Ryszard Olchawa
Keyword(s):  
Dynamic Properties ◽  
Fulvic Acids ◽  
Humic And Fulvic Acids ◽  
The Impact
Sign in / Sign up

Export Citation Format

Share Document