scholarly journals Measurement analysis of braking forces and braking coefficient at different loads of a passenger vehicle

2021 ◽  
Vol 1208 (1) ◽  
pp. 012018
Author(s):  
Ramo Halilagić ◽  
Nedim Hodžić
Keyword(s):  
Relative Difference ◽  
Front Axle ◽  
Test Results ◽  
Passenger Vehicle ◽  
Front Passenger ◽  
Measurement Analysis ◽  
Braking Force ◽  
The Stability ◽  
Inspection Station ◽  
Increasing Load

Abstract This paper presented an analysis of the braking force efficiency, i.e. its intensity in the case. It presented an analysis of the efficiency of braking forces, i.e. their intensity in the case when the load of a passenger vehicle was gradually changing. The change in the load of the vehicle was done by varying the number of passengers in it from one to five which is a feature of a higher number of M1 category vehicle. By increasing in the number of passengers the weight of the vehicle varied by approximately 75kg per passenger. The experimental test was performed in the technical inspection station, i.e. on standard rollers for the brake system testing. The test results shown that the relative difference of braking forces occurred on the front axle during intensive braking and that the braking coefficient was the lowest of about 69.94% in the case when only the driver was in the vehicle. It increased with increasing load, i.e. the number of passengers in the vehicle up to 85.91% and then dropped by increasing the rear passenger behind the driver and front passenger to 80.43% which can affect the stability of the vehicle when braking in the event of a dangerous traffic situation.

scholarly journals Car braking effectiveness after adaptation for drivers with motor dysfunctions

2021 ◽  
Vol 11 (1) ◽  
pp. 617-623
Author(s):  
Adam Sowiński ◽  
Tomasz Szczepański ◽  
Grzegorz Koralewski
Keyword(s):  
Efficiency Index ◽  
Mathematical Function ◽  
Test Results ◽  
Braking Performance ◽  
Braking System ◽  
System Adaptation ◽  
Parametric Description ◽  
Limited Power ◽  
Braking Force ◽  
Selection Of

Abstract This article presents the results of measurements of the braking efficiency of vehicles adapted to be operated by drivers with motor dysfunctions. In such cars, the braking system is extended with an adaptive device that allows braking with the upper limb. This device applies pressure to the original brake in the car. The braking force and thus its efficiency depend on the mechanical ratio in the adapting device. In addition, braking performance depends on the sensitivity of the car’s original braking system and the maximum force that a disabled person can exert on the handbrake lever. Such a person may have limited power in the upper limbs. The force exerted by the driver can also be influenced by the position of the driver’s seat in relation to the handbrake lever. This article describes the research aimed at understanding the influence of the above-mentioned factors on the car braking performance. As a part of the analysis of the test results, a mathematical function was proposed that allows a parametric description of the braking efficiency index on the basis of data on the braking system, adaptation device, driver’s motor limitations, and the position of the driver’s seat. The information presented in this article can be used for the preliminary selection of adaptive devices to the needs of a given driver with a disability and to the vehicle construction.

Design of combined brake system for light weight scooters

2021 ◽  
pp. 095440702110240
Author(s):  
Yuan-Ting Lin ◽  
Chyuan-Yow Tseng ◽  
Jao-Hwa Kuang ◽  
Yeong-Maw Hwang
Keyword(s):  
Ride Comfort ◽  
Brake System ◽  
Force Distribution ◽  
Test Results ◽  
Systematic Method ◽  
Braking Performance ◽  
Evaluation Indexes ◽  
Low Costs ◽  
Braking Force ◽  
Good Agreement

The combined brake system (CBS) is a mechanism that links the front and rear brakes for scooters. For two-wheeled scooters, a CBS with appropriate braking force distribution can reduce the risk of crashing accidents due to insufficient driving proficiency. The design of the braking force distribution for a CBS is challenging to the designer because it has to fulfill many requirements such as braking performance, ride comfort, reliability, and low costs. This paper proposes a systematic method to optimize the parameters of CBS. The evaluation indexes for the design are first discussed. The steps to determine the critical parameter to meet the indexes and a method to predict braking performance are developed. Finally, driving tests are carried out to verify the effectiveness of the proposed method. Experimental results showed that the deceleration of the tested scooter equipped with the designed CBS achieves an average mean fully developed deceleration (MFDD) of 5.246 m/s2, higher than the homologation requirement. Furthermore, the proposed method’s prediction of braking performance is in good agreement with the test results, with errors <1%.

scholarly journals Analytical and Experimental Investigation of the Stability of the Rotor-Bearing System of a New Small Turbocharger

1987 ◽  
Author(s):  
H. R. Born
Keyword(s):  
Experimental Investigation ◽  
Dynamic Stability ◽  
Squeeze Film ◽  
Test Results ◽  
Flow Capacity ◽  
Squeeze Film Dampers ◽  
Rotor Bearing ◽  
The Stability ◽  
Turbine Design ◽  
Bearing System

This paper presents an overview of the development of a reliable bearing system for a new line of small turbochargers where the bearing system has to be compatible with a new compressor and turbine design. The first part demonstrates how the increased weight of the turbine, due to a 40 % increase in flow capacity, influences the dynamic stability of the rotor-bearing system. The second part shows how stability can be improved by optimizing important floating ring parameters and by applying different bearing designs, such as profiled bore bearings supported on squeeze film dampers. Test results and stability analyses are included as well as the criteria which led to the decision to choose a squeeze film backed symmetrical 3-lobe bearing for this new turbocharger design.

Durability of BFRP and Hybrid FRP Sheets under Freeze-Thaw Cycling

2010 ◽  
Vol 163-167 ◽  
pp. 3297-3300 ◽  
Author(s):  
Jia Wei Shi ◽  
Hong Zhu ◽  
Zhi Shen Wu ◽  
Gang Wu
Keyword(s):  
Mechanical Properties ◽  
Test Data ◽  
Mechanical Characteristics ◽  
Test Results ◽  
Freeze Thaw ◽  
Frp Composites ◽  
Test Parameters ◽  
The Stability ◽  
Better Than

Coupon tests were conducted to investigate the mechanical characteristics of basalt FRP (BFRP) sheet, basalt-carbon hybrid FRP sheets and the corresponding epoxy rein under the effect of freeze-thaw cycling. FRP sheets and epoxy rein coupons were subjected to up to 200 and 250 freeze-thaw cycles respectively. Test parameters included the number of freeze-thaw cycles and the types of FRP composites. Test results show that (1) BFRP sheet perform better than CFRP or GFRP sheets under high freeze-thaw cycles; (2) exposed hybrid FRP sheets not only show very little loss in mechanical properties, but also contribute to the stability of test data; (3) mechanical properties of rein epoxy decrease significantly with increasing freeze-thaw cycles.

scholarly journals Behaviour of eccentrically inclined loaded rectangular foundation on reinforced sand

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Sujata Gupta ◽  
Anupam Mital
Keyword(s):  
Bearing Capacity ◽  
Loading Conditions ◽  
Test Results ◽  
Bearing Capacity Ratio ◽  
Reinforced Sand ◽  
The Core ◽  
Capacity Ratio ◽  
Core Boundary ◽  
Rectangular Foundation ◽  
Increasing Load

Abstract This study presents the behaviour of model footing resting over unreinforced and reinforced sand bed under different loading conditions carried out experimentally. The parameters investigated in this study includes the number of reinforced layers (N = 0, 1, 2, 3, 4), embedment ratio (Df /B = 0, 0.5, 1.0), eccentric and inclined ratio (e/L, e/B = 0, 0.05, 0.10, 0.15) and (a = 0°, 7°, 14°). The test sand was reinforced with bi-axial geogrid (Bx20/20). The test results show that the ultimate bearing capacities decrease with axial eccentricity and inclination of applied loads. The test results also show that the depth of model footing increase zero to B (B = width of model footing), an increase of ultimate bearing capacity (UBC) approximated at 93%. Similarly, the multi-layered geogrid reinforced sand (N = 0 to 4) increases the UBC by about 75%. The bearing capacity ratio (BCR) of the model footing increases with an increasing load eccentricity to the core boundary of footing; if the load eccentricities increase continuity, the BCR decreases. The tilt of the model footing is increased by increasing the eccentricity and decreases with increasing the number of reinforcing layers.

scholarly journals Analysis and Calculation of Stability Coefficients of Cross-Laminated Timber Axial Compression Member

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4267
Author(s):  
Qi Ye ◽  
Yingchun Gong ◽  
Haiqing Ren ◽  
Cheng Guan ◽  
Guofang Wu ◽  
...  
Keyword(s):  
Bearing Capacity ◽  
Axial Compression ◽  
Calculation Method ◽  
National Standards ◽  
Test Results ◽  
Average Deviation ◽  
Stability Coefficient ◽  
Cross Laminated Timber ◽  
Stability Bearing Capacity ◽  
The Stability

Cross-laminated timber (CLT) elements are becoming increasingly popular in multi-storey timber-based structures, which have long been built in many different countries. Various challenges are connected with constructions of this type. One such challenge is that of stabilizing the structure against vertical loads. However, the calculations of the stability bearing capacity of the CLT members in axial compression in the structural design remains unsolved in China. This study aims to determine the stability bearing capacity of the CLT members in axial compression and to propose the calculation method of the stability coefficient. First, the stability coefficient calculation theories in different national standards were analyzed, and then the stability bearing capacity of CLT elements with four slenderness ratios was investigated. Finally, based on the stability coefficient calculation formulae in the GB 50005-2017 standard and the regression method, the calculation method of the stability coefficient for CLT elements was proposed, and the values of the material parameters were determined. The result shows that the average deviation between fitting curve and calculated results of European and American standard is 5.43% and 3.73%, respectively, and the average deviation between the fitting curve and the actual test results was 8.15%. The stability coefficients calculation formulae could be used to predict the stability coefficients of CLT specimens with different slenderness ratios well.

scholarly journals Stability and Emission Characteristics of Diesel-Ethanol-Coconut Methyl Ester Blends for the Diesel Engines

2015 ◽  
Vol 14 (2) ◽  
pp. 1
Author(s):  
Tanti Ardiyati ◽  
Nathaniel P. Dugos ◽  
Susan A. Roces ◽  
Masaaki Suzuki ◽  
Kusnanto Kusnanto
Keyword(s):  
Methyl Ester ◽  
Diesel Engines ◽  
Emission Characteristics ◽  
Test Results ◽  
Fuel Blends ◽  
Fuel Consumption Rate ◽  
Efficient Combustion ◽  
Smoke Opacity ◽  
The Stability ◽  
Blended Fuels

The stability and emission characteristics of diesel-ethanol-coconut methyl ester (CME) blends were studied to determine the most suitable fuel blends to be applied in diesel engines. This is done in order to assess the potential of the blends as a substitute for commercially available diesel fuel used in diesel engine. The stability results of the blends using 100% and 99.5% ethanol purity showed that the fuel blends containing ethanol up to 10% and CME of 5% and greater exhibited high mutual solubility at any temperature range and were resistant to microbial growths after 3 months storage. Engine operations at low speed especially at idle-no load and using a bigger size engine lead to a minimum ignition delay and result in lower fuel consumption rate. The emission test results with the new- blended fuels showed a reduction in CO2 and increasing percentage by volume of CO2 compared to commercially available diesel. The blends could deliver an efficient combustion and could run efficiently since production of the CO2 gases is higher than that of CO. The blends of 80% diesel, 5% ethanol, 10% CME; and 80% diesel, 10% ethanol, 10% CME could reduce the smoke opacity compared to commercially available diesel.

scholarly journals Lyapunov Based Estimation of Flight Stability Boundary under Icing Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Binbin Pei ◽  
Haojun Xu ◽  
Yuan Xue
Keyword(s):  
Equilibrium Point ◽  
External Disturbance ◽  
Stability Boundary ◽  
Wind Tunnel Test ◽  
Test Results ◽  
Theoretical Support ◽  
Effect Model ◽  
Short Period ◽  
The Stability ◽  
Period Model

Current fight boundary of the envelope protection in icing conditions is usually defined by the critical values of state parameters; however, such method does not take the interrelationship of each parameter and the effect of the external disturbance into consideration. This paper proposes constructing the stability boundary of the aircraft in icing conditions through analyzing the region of attraction (ROA) around the equilibrium point. Nonlinear icing effect model is proposed according to existing wind tunnel test results. On this basis, the iced polynomial short period model can be deduced further to obtain the stability boundary under icing conditions using ROA analysis. Simulation results for a series of icing severity demonstrate that, regardless of the icing severity, the boundary of the calculated ROA can be treated as an estimation of the stability boundary around an equilibrium point. The proposed methodology is believed to be a promising way for ROA analysis and stability boundary construction of the aircraft in icing conditions, and it will provide theoretical support for multiple boundary protection of icing tolerant flight.

scholarly journals SYNTHESIS AND STABILITY OF RESVERATROL-CONJUGATED GOLD NANOPARTICLES MODIFIED WITH POLYETHYLENE GLYCOL

2020 ◽  
pp. 230-236
Author(s):  
RADITYA ISWANDANA ◽  
RICHA NURSELVIANA ◽  
SUTRIYO SUTRIYO
Keyword(s):  
Particle Size ◽  
Gold Nanoparticles ◽  
Polyethylene Glycol ◽  
Zeta Potential ◽  
High Performance ◽  
Entrapment Efficiency ◽  
Test Results ◽  
Novel Method ◽  
The Stability ◽  
Phosphate Buffered Saline

Objective: Gold nanoparticles (AuNPs) are highly useful for drug delivery, but their application is limited by their stability as they readily aggregate.This issue can be prevented by adding a stabilizing agent such as resveratrol (RSV), which is a polyphenol derived from plants, that is used to preventcancer. Therefore, we propose a novel method to prepare stable RSV-conjugated nanoparticles modified with polyethylene glycol (RSV-AuNP-PEG).Methods: In the first step, the Turkevich method was used to synthesize the AuNPs. Then, PEG was added as stabilizer agent and conjugated with RSV.The synthesized conjugates were characterized using ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, particle sizeanalysis, and high-performance liquid chromatography.Results: The obtained RSV-AuNP-PEG had a particle size of 83.93 nm with a polydispersity index (PDI) of 0.562 and formed a translucent purple-redfluid in solution. The zeta potential was −22.9 mV, and the highest entrapment efficiency was 75.86±0.66%. For comparison, the RSV-AuNP solutionwas purple and turbid, the particle size was 51.97 nm with a PDI of 0.694, and the zeta potential was −24.6 mV. The stability test results showed thatthe storage stability of RSV-AuNP-PEG was better than that of AuNP-RSV. Further, the RSV-AuNP-PEG was shown to be most stable in 2% bovine serumalbumin (BSA) while the AuNP-RSV was most stable in 2% BSA in phosphate-buffered saline pH 7.4.Conclusion: These results show that modification of RSV-conjugated AuNPs with PEG effectively prevents their aggregation in storage, but only incertain mediums.

scholarly journals Stability of Glucose Concentrations in Frozen Plasma

2020 ◽  
pp. 193229682096365
Author(s):  
Stefan Pleus ◽  
Guido Freckmann ◽  
Annette Baumstark ◽  
Cornelia Haug
Keyword(s):  
Venous Blood ◽  
Relative Difference ◽  
Plasma Samples ◽  
Conflicting Information ◽  
Long Term Storage ◽  
The Stability ◽  
Relative Differences ◽  
Frozen Plasma ◽  
Laboratory Analyzer

Background: Conflicting information is available regarding the stability of glucose concentrations in frozen plasma samples. Clinical trials could benefit from such long-term storage because it would allow usage of a central laboratory with higher-quality laboratory analyzers in contrast to mobile analyzers in a decentralized setting. Methods: In this study, venous blood samples were collected in lithium-heparin gel tubes. Plasma was separated immediately after blood was drawn, and from each of the 21 plasma samples, 6 aliquots were prepared for measurement at 6 time points: immediately and after 2, 4, 6, 8, and 12 weeks. Between sampling and measurement, aliquots were stored at less than −20°C. Transport on dry ice was simulated by placing aliquots in a −80°C freezer for 5 days between weeks 8 and 12. Measurements were performed on a hexokinase-based laboratory analyzer. Average relative differences and corresponding 99% confidence intervals (CIs) were calculated between the stored aliquots’ and the immediately measured aliquots’ glucose concentrations. Glucose concentrations were deemed stable as long as average relative differences were ≤±2.5%. Results: Over the whole 12-weeks duration, the largest average relative difference was −1.82% (99% CI: –2.25% to −1.39%). Shorter storage durations tended to lead to less bias. Conclusion: In this study, the stability of glucose concentrations in frozen plasma samples obtained with lithium-heparin gel tubes could be shown for up to 12 weeks. Future studies should be performed to assess whether this is independent of the glucose analyzer and the type of sampling tube used.

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