Design and test of the airflow adjustment test bench for orchard air-assisted spraying

The aim was to assess the influence of moderate cigarette-smoking on the clinical (bleeding on probing [BoP] and probing depth [PD]) and radiographic (crestal bone resorption [CBR]) around cement- and screw-retained dental implants at 5 years’ follow-up. A questionnaire was used to collect information about age, gender, smoking history, duration of implants in function, jaw location of the implant, and daily toothbrushing and flossing. Peri-implant BoP, PD and CBR were measured in all groups. Group comparisons were performed using one-way analysis of variance and for multiple comparisons, the Bonferroni Post hoc adjustment test was performed. Level of significance was set at P<0.05. Forty-eight patients (25 smokers and 23 non-smokers) had cement-retained dental implants; and 48 (24 smokers and 24 non-smokers) had screw-retained dental implants. Among patients with cement and screw-retained dental implants, PD (P<0.05) and CBR (P<0.05) were significantly higher among smokers than non-smokers. The peri-implant sites that demonstrated BoP were statistically significantly higher among non-smokers (P<0.05) than smokers among patients with cement- and screw-retained dental implants. There was no statistically significant difference in peri-implant PD and CBR among smokers with cement- and screw-retained dental implants. Among non-smokers with cement and screw-retained dental implants, there was no statistically significant difference in BoP, PD and CBR. Cigarette-smoking is associated with an increased PD and CBR around cement- and screw-retained dental implants. Cigarette-smoking increases peri-implant soft tissue inflammation as well as loss of crestal bone and this relationship is independent of the type of implant retention protocol used.The author recommends that cement- and screw-retained dental implants are suitable for prosthesis restoration in non-smokers. Further studies on dual-smokers (individuals smoking cigarettes and other forms of tobacco products) are needed related to the clinicoradiographic inflammatory parameters around cement- and screw-retained dental implants

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Investigations of Road Wear Caused by Studded Tires

Tire Science and Technology ◽

10.2346/tire.14.420101 ◽

2014 ◽

Vol 42 (1) ◽

pp. 2-15

Author(s):

Johannes Gültlinger ◽

Frank Gauterin ◽

Christian Brandau ◽

Jan Schlittenhard ◽

Burkhard Wies

Keyword(s):

Traffic Safety ◽

Test Bench ◽

Operating Conditions ◽

Test Method ◽

Analytical Models ◽

The Road ◽

Driving Speed ◽

Major Factors ◽

Tire Friction ◽

Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

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Analysis of the Impact of the Frequency Range of the Tensometer Bridge and Projectile Geometry on the Results of Measurements by the Split Hopkinson Pressure Bar Method

Metrology and Measurement Systems ◽

10.2478/mms-2013-0047 ◽

2013 ◽

Vol 20 (4) ◽

pp. 555-564 ◽

Cited By ~ 12

Author(s):

Wojciech Moćko

Keyword(s):

Test Bench ◽

Split Hopkinson Pressure Bar ◽

Dynamic Deformation ◽

Spectral Width ◽

Hopkinson Pressure Bar ◽

Computing Environment ◽

Split Hopkinson ◽

Pressure Bar ◽

The Impact ◽

Bench Model

Abstract The paper presents the results of the analysis of the striker shape impact on the shape of the mechanical elastic wave generated in the Hopkinson bar. The influence of the tensometer amplifier bandwidth on the stress-strain characteristics obtained in this method was analyzed too. For the purposes of analyzing under the computing environment ABAQUS / Explicit the test bench model was created, and then the analysis of the process of dynamic deformation of the specimen with specific mechanical parameters was carried out. Based on those tests, it was found that the geometry of the end of the striker has an effect on the form of the loading wave and the spectral width of the signal of that wave. Reduction of the striker end diameter reduces unwanted oscillations, however, adversely affects the time of strain rate stabilization. It was determined for the assumed test bench configuration that a tensometric measurement system with a bandwidth equal to 50 kHz is sufficient

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