scholarly journals A Comparative Study on Skid Resistance of Concrete Pavements Differing in Texturing Technique

Materials ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 178
Author(s):  
Pawel Gierasimiuk ◽  
Marta Wasilewska ◽  
Wladyslaw Gardziejczyk
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Skid Resistance ◽  
Concrete Pavements ◽  
Aggregate Concrete ◽  
Homogeneous Groups ◽  
Significant Difference ◽  
Profile Depth ◽  
The Mean ◽  
Post Hoc

The paper presents a comparison of the skid resistance of concrete pavements textured with different techniques in the process of simulating phenomena occurring in actual road conditions. Tests were carried out on five different texturing methods for concrete pavements: burlap drag (BuD), brush drag (BrD), transverse tining (TT), longitudinal tining (LT) and exposed aggregate concrete (EAC). Changes in the skid resistance were recorded by measurements with a British pendulum tester and a circular texture meter before and during the simulation of the abrasion (1st phase of test) and polishing (2nd phase of test) of specimens using a slab polisher. The results of BPN (British pendulum number) and MPD (mean profile depth) allowed us to determine the influence of microtexture and macrotexture on skid resistance. Analysis of variance showed that the method of texturing concrete pavements has a significant influence on the mean BPN values as well as the MPD parameter at each stage of the test. In order to distinguish homogeneous groups in terms of BPN and MPD levels at the particular stages of the process, the Tukey’s HSD (honest significant difference) post-hoc test was performed. It was found that EAC obtained the most favorable results of all the tested pavement types. Due to the high value of the MPD coefficient after the test and the appropriate values of the friction coefficient, it was confirmed that the EAC pavement will be a durable solution due to the guarantee of skid resistance on high-speed roads during its service life.

scholarly journals Oxygen Saturation in the Dental Pulp of Maxillary and Mandibular Molars - Part 2

2017 ◽  
Vol 28 (6) ◽  
pp. 704-709 ◽  
Author(s):  
Carlos Estrela ◽  
Keila SA Oliveira ◽  
Ana Helena G Alencar ◽  
Fernando B Barletta ◽  
Cyntia RA Estrela ◽  
...  
Keyword(s):  
Oxygen Saturation ◽  
Dental Pulp ◽  
Oxygen Saturation Level ◽  
Significance Level ◽  
Cold Stimulus ◽  
Mandibular Molars ◽  
Maxillary Molars ◽  
Significant Difference ◽  
The Mean ◽  
Post Hoc

Abstract This study determined the oxygen saturation (SaO2) in dental pulp of healthy maxillary and mandibular molars. Mean of SaO2 was evaluated in 112 maxillary and mandibular molars using pulse oximetry. Quantitative variables were described by mean and standard deviation. Variables with symmetric distribution were compared by Student t test and Mann-Whitney test. Pearson’s correlation coefficient was used to correlate quantitative variables. Analysis of variance was used to assess differences in SaO2 levels between the molar groups, followed by post-hoc Tukey. The significance level established at p<0.05. Mean of oxygen saturation for the 112 molar dental pulps was 85.09%. There was no significant correlation (r=-0.007; p=0.977) between the mean of SaO2 of molar pulps with patient´s indicator finger (92.89%). There was a significant difference (p=0.037) between the mean of SaO2 of the first (85.76%) and second maxillary molars (81.87%), and it was not significant (p=0.1775) between the first and second mandibular molars. Maxillary molars had lower pulpal SaO2 (83.59%) than mandibular molars (86.89%) (p=0.018). The mean of the patient’s response time to the cold stimulus was 1.12 s (maxillary molars 1.25 s and mandibular molars 0.99 s)(p=0.052). There was no significant correlation between the time response of the patient to the cold stimulus and the SaO2 for molars. The mean oxygen saturation level was 85.09%. The mandibular molars presented higher SaO2 level than maxillary molars.

Analysis of Pedestrian Gait and Perception-Reaction at Signal-Controlled Crosswalk Intersections

2000 ◽  
Vol 1705 (1) ◽  
pp. 20-25 ◽  
Author(s):  
Thomas F. Fugger ◽  
Bryan C. Randles ◽  
Anthony C. Stein ◽  
William C. Whiting ◽  
Brian Gallagher
Keyword(s):  
Steady State ◽  
High Speed ◽  
Real Life ◽  
Light Illumination ◽  
Acceleration Rate ◽  
Significant Difference ◽  
Pedestrian Accident ◽  
Walking Velocity ◽  
The Mean ◽  
Walking Speeds

Pedestrian accident analysis and reconstruction remain the most difficult areas for the accident analyst. Although data relating to average pedestrian walking speeds, perception-reaction, and pedestrian accident reconstruction can be found in the literature, proper pedestrian study data pertaining to real-life situations are lacking. Pedestrians were observed at signal-controlled crosswalk intersections, and their perception-reaction to the crosswalk signal, acceleration rate to reach constant walking velocity, and average walking speed once steady state velocity is achieved were determined. Experimental test data collected regarding pedestrian gait analysis, initiation, and steady state walking speeds are presented. “Real world” pedestrian observations were gathered at a variety of intersections, ranging from busy downtown intersections to suburban intersections throughout the greater Los Angeles area. Kinematic data on pedestrian movements were obtained using high-speed digital video. A high-speed video motion analysis system was used to reduce the data and to obtain the mean acceleration and time to steady state walking velocity. Perception-reaction data collected on 288 subjects show a significant percentage of the pedestrians initiating movement within 1 s of Walk light illumination. Some differences were observed when the state of anticipation was being considered, and these results are presented. The mean acceleration (0.14 ± 0.09 g) and steady state velocity (1.36 ± 0.24 m/s) values did not demonstrate a significant difference between males and females. The width of the street or initial state of anticipation did not have an effect on either mean acceleration values or steady state velocities.

scholarly journals The Effect of Glaze Coating on Wear Resistance of Some Acrylic Denture Teeth: An In Vitro Study

2021 ◽  
Vol 13 (2) ◽  
pp. 47-51
Author(s):  
Samaneh Abbasi ◽  
Soodabe Ebrahimi ◽  
Arash Shisheian ◽  
Maryam Farhadian
Keyword(s):  
Wear Resistance ◽  
In Vitro Study ◽  
Resistance Rate ◽  
Vitro Study ◽  
Wear Rates ◽  
Denture Teeth ◽  
Significant Difference ◽  
The Mean ◽  
Post Hoc

Background: Acrylic resin teeth wear resistance has an important role in the denture longevity. This study aimed to clarify the effect of glaze coating on wear resistance of three types of artificial acrylic teeth. Methods: In this in vitro study, the wear resistance rate of three of acrylic denture teeth (GENIUS, STON and CLASSIC) was compared with Ivoclar teeth (n=25/group). The wear resistance was measured by estimating the weight loss in pre and post removing glaze coating, following 5000 cycles in the chewing simulator device. Data analysis was made using paired t test, one-way ANOVA and Tukey’s post hoc test. Results: ANOVA test showed that there was no significant difference between the mean amount of wear of GENIUS, CLASSIC, STON and IVOCLAR teeth in the first stage (P <0.061), but this difference was significant (P <0.001) in the second stage. The result of Tukey post hoc test showed that wear rates of GENIUS were significantly lower than other groups (P<0.001). Comparison between the mean wear rates of each dental group at the first and second stages showed a significant difference between average teeth wear resistance of CLASSIC, STON and IVOCLAR in the first and second stages (P <0.001). Conclusions: In conclusion, the teeth wear resistance of STON and CLASSIC were similar to IVOCLAR. Also, after removing the glaze coating, the teeth wear resistance decreased in all groups but was not statistically significant for group GENIUS.

STUDY ON THE TRIBOLOGICAL BEHAVIOR OF CUTTING TOOLS COATED WITH FILMS

2011 ◽  
Vol 25 (31) ◽  
pp. 4261-4264 ◽  
Author(s):  
MANABU YASUOKA
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Cutting Tool ◽  
Cutting Tools ◽  
High Speed Steel ◽  
Frictional Properties ◽  
Coated Tool ◽  
Significant Difference ◽  
The Difference ◽  
Pin On Disk

A hard film coat can improve a tool's performance. In this study, the frictional properties of an uncoated tool and a coated tool with TiN were measured against that of SCM440 (42 CrMo 4) steel. The results showed there was no significant difference between the friction coefficient of the high-speed steel tool and the tool coated with TiN but the friction coefficient of uncoated tool was slightly lower than that of the steel. In the second part of the study, coats of TiN , TiC , CrN , and TiAlN were deposited on high-speed steel and the wear characteristics were determined with a pin-on-disk wear examination. The differences in the friction coefficients were attributed to the difference in the wear of the slipping material. There were large differences in the adhesion characteristics on the surface of the slipping material. The author suggest that these differences influence the characteristics of the cutting tool.

scholarly journals Comparative analysis of the anterior and posterior length and deflection angle of the cranial base, in individuals with facial Pattern I, II and III

2013 ◽  
Vol 18 (1) ◽  
pp. 69-75 ◽  
Author(s):  
Guilherme Thiesen ◽  
Guilherme Pletsch ◽  
Michella Dinah Zastrow ◽  
Caio Vinicius Martins do Valle ◽  
Karyna Martins do Valle-Corotti ◽  
...  
Keyword(s):  
Deflection Angle ◽  
Cranial Base ◽  
Profile Angle ◽  
Mean Values ◽  
Anterior Cranial Base ◽  
Significant Difference ◽  
Facial Pattern ◽  
Caucasian Patients ◽  
The Mean ◽  
Post Hoc

OBJECTIVE: This study evaluated the variations in the anterior cranial base (S-N), posterior cranial base (S-Ba) and deflection of the cranial base (SNBa) among three different facial patterns (Pattern I, II and III). METHOD: A sample of 60 lateral cephalometric radiographs of Brazilian Caucasian patients, both genders, between 8 and 17 years of age was selected. The sample was divided into 3 groups (Pattern I, II and III) of 20 individuals each. The inclusion criteria for each group were the ANB angle, Wits appraisal and the facial profile angle (G'.Sn.Pg'). To compare the mean values obtained from (SNBa, S-N, S-Ba) each group measures, the ANOVA test and Scheffé's Post-Hoc test were applied. RESULTS AND CONCLUSIONS: There was no statistically significant difference for the deflection angle of the cranial base among the different facial patterns (Patterns I, II and III). There was no significant difference for the measures of the anterior and posterior cranial base between the facial Patterns I and II. The mean values for S-Ba were lower in facial Pattern III with statistically significant difference. The mean values of S-N in the facial Pattern III were also reduced, but without showing statistically significant difference. This trend of lower values in the cranial base measurements would explain the maxillary deficiency and/or mandibular prognathism features that characterize the facial Pattern III.

scholarly journals Effect of Galla Chinensis on Remineralization of Early Dentin Lesion

2020 ◽  
Vol 14 (04) ◽  
pp. 651-656
Author(s):  
Hend Mahmoud Abdel-Azem ◽  
Ahmed Fawzy Abo Elezz ◽  
Rehab Khalil Safy
Keyword(s):  
Treatment Time ◽  
Analysis Data ◽  
Environmental Scanning ◽  
X Ray ◽  
Parametric Data ◽  
Significant Difference ◽  
Ph Cycling ◽  
The Mean ◽  
Post Hoc

Abstract Objective This study aimed to investigate the efficacy of the Galla chinensis extract (GCE) on early dentin lesion remineralization. Materials and Methods Seventy-two dentin specimens were divided into three groups according to the treatment solution. In group S1, specimens were treated with GCE; in group S2, the specimens were treated with sodium fluoride (NaF); meanwhile, specimens of group S3 were treated with distilled water (DW). Each group was further subdivided into two subgroups according to the treatment time (1 minute and 5 minutes). An in vitro pH-cycling model for 12 days was done. Subsequently, surface microhardness (SMH) of the specimens, elemental analysis, and their micromorphological appearance were evaluated. Statistical Analysis Data were statistically analyzed. One-way analysis of variance was used to compare numerical (parametric) data between more than two separate groups followed by post hoc Tukey. Results There was no significant difference between the mean SMH of dentin between NaF and GCE groups. Regarding the time, the 5-minute treatment with NaF and DW groups recorded higher mean SMH value of dentin than the 1-minute treatment group. Meanwhile, for GCE groups, the 1-minute immersion recorded higher mean SMH value than the 5-minute immersion without any significant difference between them. The microhardness results were confirmed by environmental scanning electron microscope and energy dispersive X-ray analysis results. Conclusion GCE could be used as an effective alternative for dentin remineralization.

scholarly journals Safe Pedestrian Behaviours among Children Aged 7 to 9 in Malaysia

2019 ◽  
Vol 30 (2) ◽  
pp. 61-65
Author(s):  
Low Fin ◽  
Nurfatin Suhaimi ◽  
Nur Nor ◽  
Amelia Ghani
Keyword(s):  
Random Sample ◽  
Road Safety ◽  
Safety Education ◽  
The Road ◽  
Large N ◽  
Significant Difference ◽  
The Mean ◽  
Low Levels ◽  
Post Hoc ◽  
One Way Anova

The present study examined safe pedestrian behaviours according to the Malaysian Road Safety Education module among 7-year-old to 9-year-old children in Malaysia. A survey was conducted with a relatively large (n = 1206) random sample of children aged 7 to 9 years old, drawn from 24 selected schools in six states in Malaysia based on the highest numbers of crash cases. Analysis of one-way ANOVA revealed a statistically significant difference in safe pedestrian behaviours between different ages. Post hoc comparisons using the Tukey HSD test indicated that the mean score of safe pedestrian behaviours for 7-year-old children was significantly higher than that of 8-year-old children (p = .004) and 9-year-old children (p = .021). No statistically significant difference was revealed between the 8-year-olds and 9-year-olds (p = .859) at the 0.05 level. Although many children reported safe pedestrian behaviours, low levels of certain safe pedestrian behaviours were also reported – less than 30% of the children aged 7 to 9 reported to ‘always’ wear bright clothes, walk against the traffic, and wave at the drivers to cross the road. In addition, a small percentage (9.9-13.6%) of children aged 7 to 9 also reported to ‘always’ wear dark clothes at night, cross the street between parked cars, and run to cross the road. These findings may inform programs to improve children’s safe pedestrian behaviours.

scholarly journals Disentangling the role of income level on premium brand perceived quality, awareness, association, and loyalty: A comparative study within Thailand and Indonesia

2021 ◽  
Vol 18 (1) ◽  
pp. 80
Author(s):  
Komm Pechinthorn ◽  
Nico Irawan ◽  
Kyawt Shinn Thant Zin ◽  
Sineenat Suasungnern ◽  
Jirangrug Samarkjarn ◽  
...  
Keyword(s):  
Low Income ◽  
Income Level ◽  
Perceived Quality ◽  
Online Questionnaire ◽  
Significant Difference ◽  
The Mean ◽  
Post Hoc ◽  
Quality Awareness ◽  
Low Income Consumers

The level of income is one of the specific consumer conditions that susceptible to influence their brand decision-making. Unfortunately, studies on the influence of income mainly focused on price without considering the relationship between brand and consumers. This study aims to examine how brand perceived quality, awareness, association, and loyalty related to the level of income in emerging countries like Thailand and Indonesia. Premium and high-class coffee chain brands choose as the object of this study as the exponential growth of the coffee culture in both countries. A total of 283 respondents have completed an online questionnaire and verified it to be processed into the analysis of variance (ANOVA) and LSD post hoc test for multiple comparison statistical analysis. The result of this study shows that although high-income and low-income consumers in Thailand tend to have the same perceived quality toward the premium coffee brand, in general, there is a significant difference in the mean of brand perceived quality, awareness, and association between various consumers income level in Thailand. Interestingly, this study found that there is no significant difference in the mean of premium coffee brand perceived quality, awareness, association, and loyalty within the group of income levels in Indonesia. This indicates that Indonesians tend to ignore how much money they have in their pocket when it comes to coffee as the coffee culture becoming a new habit and lifestyle.

scholarly journals Estimation of Total Fluoride Concentration, Total Soluble Fluoride Concentration and pH among Various Brands of Toothpastes

2021 ◽  
Author(s):  
Praneetha D Rani ◽  
Vijaya Hegde
Keyword(s):  
Group Analysis ◽  
Fluoride Concentration ◽  
In Vitro Study ◽  
Significant Difference ◽  
The Mean ◽  
The Difference ◽  
Institute Of Technology ◽  
Level Of Significance ◽  
Post Hoc

Introduction: Fluoride toothpastes are a major reason for the decline in dental caries globally. For fluoride toothpaste to be effective, an adequate amount of Total Soluble Fluoride (TSF) must be available in the toothpastes. Aim: To determine and compare the Total Fluoride (TF), TSF and pH among various toothpaste brands. Materials and Methods: An in-vitro study was conducted during October 2019 on 20 toothpaste samples, which belonged to four groups namely, herbal toothpastes group, nonherbal toothpastes group, medicated toothpastes group and kids toothpastes group. Analysis of the samples was done at the Department of Environmental Engineering Laboratory, National Institute of Technology, Surathkal, Karnataka, India. The TF and the TSF concentration was determined using fluoride ion electrode. The pH was determined using pH meter. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS version 19.0). Analysis of variance (ANOVA) was used by Tukey’s post-hoc test to determine the difference between groups. The level of significance was kept at 0.05. Results: The results showed that there was a significant difference between the toothpaste types for mean TF concentration (p=0.004). The post-hoc test showed that there was a significant difference between herbal and nonherbal toothpastes (p=0.041) where the mean TF concentration for nonherbal toothpastes was 1095.20 ppm when compared to herbal toothpastes was 704.40 ppm. The results showed that there was a siginificant difference between the toothpaste types for Mean TSF concentration (p<0.003). There was a significant difference between medicated and kids toothpastes (p=0.024) where the mean total soluble fluoride concentration for medicated toothpastes was 938.60 ppm when compared to the kids toothpastes was 521.20 ppm. Conclusion: The present study showed that pH of all the toothpastes were either neutral or alkaline and the TSF concentration was less when compared to TF concentrations.

scholarly journals An Evaluation on Dental Students’ Performance during the First Year of Covid-19 Pandemic

2021 ◽  
pp. 84-92
Author(s):  
Hazira M Yusof ◽  
Wan Nor Syariza Wan Ali ◽  
Nusima Mohamed
Keyword(s):  
Online Learning ◽  
Final Examination ◽  
Learning Method ◽  
Learning Methods ◽  
Examination Score ◽  
Examination Performance ◽  
Significant Difference ◽  
The Mean ◽  
Final Examination Performance ◽  
Post Hoc

As with other university programs, dental school has been affected during the Covid-19 pandemic due to physical distancing and clinical restriction. Covid-19 pandemic changes the original method of study with the swift shift to online learning, which may affect students’ performance. The objective of this study was to assess the effect of online learning methods on the final examination performance for dental undergraduate students in their clinical years in a public university in Malaysia. One-way analysis of variance (ANOVA) and post-hoc Tukey tests were conducted to compare the effect of learning methods on the mean examination score, by comparing clinical students from the year of 2018 and 2019 face-to-face (f2f) learning method as compared to fully online learning in 2020. The analysis shows that there is a statistically significant difference on final exam performance at p < 0.05 for Year 3 [F (2, 102) = 11.68] and Year 5 [F(2, 95) = 22.32]. Post-hoc Tukey HSD test indicates that the mean examination result for 2019 is significantly different from 2020 and 2018 even though the same learning method was employed for the latter. There was also no statistically significant difference for when the 2020 cohort is compared to the 2018 cohort for both Year 3 and Year 5. There was no statistically significant difference in mean examination score across all cohorts for Year 4 students. Although limited in scope, the conclusion of this study was that, f2f learning method has no significant difference with online learning in terms of final examination performance.

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