Initial cooling of pavements and the development of pavement cooling charts

1990 ◽  
Vol 17 (1) ◽  
pp. 94-101 ◽  
Author(s):  
S. White ◽  
G. Heiman ◽  
G. Huber ◽  
R. Besant ◽  
A. Bergan
Keyword(s):  
Asphalt Concrete ◽  
Initial Temperature ◽  
Weather Conditions ◽  
Early Spring ◽  
Cold Weather ◽  
Canadian Prairies ◽  
Factors Affecting ◽  
Final Density ◽  
The Subject ◽  
Pavement Temperature

A relatively short highway construction season exists on the Canadian prairies and typically the paving season extends from May to October. Highway engineers and contractors are continually confronted with unfavorable weather conditions during the early spring and latter parts of the fall paving season. During these periods of cooler weather, the decision as to whether or not to allow paving to continue or begin becomes very difficult, since freshly laid pavements cool quickly and proper compaction is difficult to attain. The final density obtained in a pavement depends critically on its initial temperature and cooling rate. This study researches the subject of pavement cooling and investigates the feasibility of cold-weather paving. The results of this study illustrate the significance of the factors affecting pavement cooling and provide information for improving the paving specifications used by Saskatchewan Highways and Transportation. This study also shows that the short paving season which exists in Saskatchewan can be extended under certain conditions. Extension of the construction season into colder weather will provide financial and various other benefits, not only to Saskatchewan Highways and Transportation but also to paving contractors and the general public. Key words: pavement cooling, pavement temperature, computer simulation, compaction, asphalt concrete.

Factors Affecting Overlay Ride Quality

2000 ◽  
Vol 1712 (1) ◽  
pp. 58-65
Author(s):  
Kevin K. McGhee
Keyword(s):  
Asphalt Concrete ◽  
Time Of Day ◽  
Ride Quality ◽  
Factors Affecting ◽  
Original Surface ◽  
State Highway ◽  
The Subject ◽  
Asphalt Overlays ◽  
Special Provision ◽  
Highway System

A study was conducted to identify the predominant factors that affect the achievable smoothness of asphalt overlays. The subject was approached from the perspective of a contracting entity (state highway agency). The basis of the study was a roughness survey that incorporated 4270 lane-km (2,650 lane-mi) and two full construction seasons with hot-mix asphalt concrete paving. Among the variables found to be related to the achievable smoothness were the functional classification (highway system), original surface roughness, and a special provision for smoothness. Variables that were found to be not significantly related to the smoothness achieved included surface mix type, the application of additional structural layers, the use of milling, and time-of-day restrictions on construction activities (i.e., nighttime paving).

Vulnerability of sweet cherry cultivars to continuous periods of spring frosts in Plovdiv, Bulgaria

2020 ◽  
Vol 12 (4) ◽  
pp. 348-352
Author(s):  
S. Malchev ◽  
S. Savchovska
Keyword(s):  
Sweet Cherry ◽  
Weather Conditions ◽  
Frost Damage ◽  
Cold Weather ◽  
Bud Burst ◽  
Intermediate Group ◽  
Air Temperatures ◽  
Wide Range ◽  
Group Form ◽  
Sweet Cherry Cultivars

Abstract. The periods with continuous freezing air temperatures reported during the spring of 2020 (13 incidents) affected a wide range of local and introduced sweet cherry cultivars in the region of Plovdiv. They vary from -0.6°C on March 02 to -4.9°C on March 16-17. The duration of influence of the lowest temperatures is 6 and 12 hours between March 16 and 17. The inspection of fruit buds and flowers was conducted twice (on March 26 and April 08) at different phenological stages after continuous waves of cold weather conditions alternated with high temperatures. During the phenological phase ‘bud burst’ (tight cluster or BBCH 55) some of the flowers in the buds did not develop further making the damage hardly detectable. The most damaged are hybrid El.28-21 (95.00%), ‘Van’ (91.89%) and ‘Bing’ (89.41%) and from the next group ‘Lapins’ (85.98%) and ‘Rosita’ (83.33%). A larger intermediate group form ‘Kossara’ (81.67%), ‘Rozalina’ (76.00%), ‘Sunburst’ (75.00%), ‘Bigarreau Burlat’ (69.11%) and ‘Kuklenska belitza’ (66.67%). Candidate-cultivar El.17-90 ‘Asparuh’ has the lowest frost damage values of 55.00% and El.17-37 ‘Tzvetina’ with damage of 50.60%.

Effectiveness of Flood Protection Project Valuation Methods

2015 ◽  
Vol 10 (3) ◽  
pp. 275-289
Author(s):  
Tadeusz Liziński ◽  
Marcin Bukowski ◽  
Anna Wróblewska
Keyword(s):  
Essential Element ◽  
Weather Conditions ◽  
Point Of View ◽  
Flood Protection ◽  
Costs And Benefits ◽  
Protection Measures ◽  
Investment Projects ◽  
Market Values ◽  
Project Valuation ◽  
The Subject

Projects for flood protection are increasingly the subject of investment projects in the field of water management. This is related to the increasing frequency of worldwide threats caused by extreme weather conditions, including extremely high rainfall causing floods. Technical and nontechnical flood protection measures are also increasing in importance. In the decision-making process, it is necessary to take into account both the costs and benefits of avoiding losses, including an analysis of social benefits, whose valuation of non-market goods is an essential element. A comprehensive account of projects in the field of flood protection based on the estimated costs and benefits of the investment allows the economic efficiency from a general social point of view to be determined. Previous evaluations of the effectiveness of investment projects have mainly taken into account only categories and market values. The aim of the article is to identify the possibilities to expand the values of non-market assessments and categories formulated on the basis of the theoretical economics of the environment. 

Heating up trickling filters to tackle cold weather conditions

2000 ◽  
Vol 41 (1) ◽  
pp. 163-166 ◽  
Author(s):  
W. Gebert ◽  
P.A. Wilderer
Keyword(s):  
Waste Heat ◽  
Treatment Plant ◽  
Weather Conditions ◽  
Pilot Scale ◽  
Cold Weather ◽  
Filling Material ◽  
Trickling Filter ◽  
Biofilm Thickness ◽  
Trickling Filters ◽  
Biofilm Support

The investigated effects of heating the filling material in trickling filters were carried out at the Ingolstadt wastewater treatment plant, Germany. Two pilot scale trickling filters were set up. Heat exchanger pipings were embedded in the filter media of one of these trickling filters, and the temperature in the trickling filter was raised. The other trickling filter was operated under normal temperature conditions, and was used as a control. The results clearly demonstrate that the performance of trickling filters cannot be constantly improved by heating the biofilm support media. A sustained increase of the metabolic rates did not occur. The decrease of the solubility of oxgen in water and mass transfer limitations caused by an increase of the biofilm thickness are the main reasons for that. Thus, the heating of trickling filters (e.g. by waste heat utilization) in order to increase the capacity of trickling filters under cold weather conditions cannot be recommended.

Divergent Principles of Politeness in Verbal and Non-Verbal Directive Speech Act

2018 ◽  
Vol 4 (2) ◽  
pp. 41
Author(s):  
Lindayana ◽  
Arifuddin ◽  
Halus Mandala
Keyword(s):  
High School ◽  
Qualitative Research ◽  
Learning Process ◽  
Speech Act ◽  
Senior High School ◽  
Factors Affecting ◽  
Data Source ◽  
The Subject ◽  
Directive Speech ◽  
Bahasa Indonesia

This study was conducted aiming at examining: (1) the divergent principles of politeness in students’ directive speech act (2) factors affecting politeness and impoliteness in verbal and non-verbal directive speech act produced by students at grade X in Senior High School 1 Mataram in the learning process. The subject of this study are teachers teaching Bahasa Indonesia, English, Economy, History, Math, Religion, Civic, and Science, and all students at Grade X of Science 1, Science 3 and Social 2 in Senior High School 1 Mataram. This study is a descriptive qualitative research. The data source in this study is the number of utterances produced by students and teachers in the learning process. The data were collected through observation. This study revealed that: (1) there were divergent principles of politeness in participants’ directive speech act namely single and multiple divergent principles of politeness affected by speaker intentionally accused addressees, intentionally uttered by neglecting the context, was protective to other arguments, showed emotional feeling, given critiques in impolite words and mocked at other; and (2) there were factors affecting politeness and impoliteness in verbal and non-verbal directive speech act produced by students in learning process namely linguistic factor and non-linguistic factor.

Sex of Subject, Sex of Opponent, and Opponent Ability as Factors Affecting Self-confidence in a competitive situation

1981 ◽  
Vol 3 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Charles B. Corbin
Keyword(s):  
Performance Assessments ◽  
Performance Expectations ◽  
Competitive Situation ◽  
Male And Female ◽  
Factors Affecting ◽  
Confidence Levels ◽  
Self Confidence ◽  
Mixed Factorial Design ◽  
The Subject ◽  
Sex Orientation

Male and female subjects (N = 80), ranging in age from 17 to 25 years, participated in a study designed to determine if the sex of the sex of the subject, the sex of the subject's opponent, or the perceived ability of the subject's opponent, (good vs. poor ability) affected subjects' self confidence after competing at a task (TV Pong Game) of “neutral” sex orientation. a 2 x 2 x 2 mixed factorial design, with 10 subjects assigned to each cell, was used. All subjects competed in five games against a confederate and in all cases subjects lost all but the second of the five games. Data were treated using an ANCOVA, with preperformance confidence being used as the covariate. Ragardless of sex of the opponent, females expressed postperformance confidence levels equal to males after performing against an opponent thought to be poor in ability, but they were significantly less cofident after performing against opponents perceived to be good in ability. These findings are consistent with those of Argote, Fisher, McDonald, and O'Neal (1976), who note that the performance expectations of females tend to be unstable and change with single encounters, whereas males are less likely to allow one failure to affect performance assessments.

Factors Affecting the Achievement of Students in Economic Subject

2021 ◽  
Vol 12 (3) ◽  
pp. 1330-1336
Author(s):  
Siti Hadijah Che Mat Et.al
Keyword(s):  
Teaching Methods ◽  
Teaching And Learning ◽  
Mean Value ◽  
General Interest ◽  
Factors Affecting ◽  
Teaching And Learning Environment ◽  
Learning Techniques ◽  
Economic Program ◽  
The Subject ◽  
High Level

There are various factors influencing a student’s academic achievement at any level, either primary, secondary or tertiary. These factors include attitudes, learning techniques, general interest in the subject matter, factors related to teacher, family or friends, previous achievements, teaching and learning environment and facilities, infrastructure, and teaching methods. This article explores factors affecting the achievement of student of a course offered in the economic program of universitiutaramalaysia. For this article, a total of 220 students who registered for macroeconomics course at universitiutaramalaysia were randomly selected to be the study sample. of the 220 responses, only 211 were analysed because some questionnaire forms was returned with incomplete information. these students consist of second, third and fourth year students. The study found that among the items in the lecturer preparation factor which came with high mean scores is the item "lecturer shows dedication in teaching". There is no denying that teaching and learning methods incorporating the latest technology and trends are desirable but the study shows that teaching using longstanding approach like using whiteboards is still preferable among students and gives the highest mean value of 7.44, which is a high level score. In terms of learning techniques, the study found that students are not consistent between the goals to achieve excellence with the appropriate effort taken by them. although they want to achieve high excellence in this subject but their efforts and actions are not inclined to that desire

scholarly journals Cold weather is a predisposing factor for testicular torsion in a tropical country. A retrospective study

2014 ◽  
Vol 133 (3) ◽  
pp. 187-190 ◽  
Author(s):  
Daniel de Oliveira Gomes ◽  
Rafael Rocha Vidal ◽  
Bruno Figueiredo Foeppel ◽  
Danilo Fiorindo Faria ◽  
Minori Saito
Keyword(s):  
Retrospective Study ◽  
Symptom Onset ◽  
Testicular Torsion ◽  
Weather Conditions ◽  
Cold Weather ◽  
Predisposing Factor ◽  
Tropical Country ◽  
Etiologic Role ◽  
Urological Emergency

CONTEXT AND OBJECTIVE:Testicular torsion is a medical and urological emergency because it can lead to loss of the organ. The theory of seasonal testicular torsion occurrence is based on studies from institutions located in cold and temperate regions. The objective here was to determine whether cold weather is associated with higher incidence of testicular torsion in a tropical country, such as Brazil.DESIGN AND SETTING:Retrospective study, conducted in a tertiary and teaching hospital.METHODS:Patients with acute testicular torsion confirmed by surgery between April 2006 and March 2011 were studied. Information on weather conditions at the time of symptom onset was collected.RESULTS:A total of 64 testicular torsion cases were identified. The months with the highest incidences of testicular torsion were June (16%), July (19%) and August (11%), which had the lowest mean temperatures, of 17.6 °C, 16.4 °C and 18.2 °C, respectively. Eleven percent of cases occurred during spring (October to December), 16% occurred in summer (January to March), 34% occurred in fall (April to June) and 39% occurred in winter (July to September). There was a significant association between the incidence of testicular torsion and the season (fall and winter), P < 0.001.CONCLUSIONS:Testicular torsion follows a seasonal association even in a tropical country, and is more frequent in the colder months of the year, namely fall and winter, when almost three-quarters of the cases occurred. These observations add further evidence that cold weather has an etiologic role in testicular torsion occurrence.

scholarly journals Concepts and new perspectives for long span bridges

2016 ◽  
Vol 5 (1) ◽  
pp. 75-97
Author(s):  
Fabio Brancaleoni
Keyword(s):  
Conceptual Design ◽  
Present State ◽  
Critical Parameter ◽  
State Of The Art ◽  
Span Length ◽  
Factors Affecting ◽  
Long Span Bridges ◽  
Future Developments ◽  
Long Span ◽  
The Subject

AbstractA discussion of the dominant factors affecting the behaviour of long span cable supported bridges is the subject of this paper. The main issue is the evolution of properties and response of the bridge with the size of the structure, represented by the critical parameter of span length, showing how this affects the conceptual design. After a review of the present state of the art, perspectives for future developments are discussed.

Modelling pavement temperature for winter maintenance operations

2004 ◽  
Vol 31 (2) ◽  
pp. 369-378 ◽  
Author(s):  
Aly Sherif ◽  
Yasser Hassan
Keyword(s):  
Surface Temperature ◽  
Air Temperature ◽  
Negative Impact ◽  
Weather Conditions ◽  
Statistical Modelling ◽  
Dew Point ◽  
Road Maintenance ◽  
Winter Maintenance ◽  
Pavement Surface ◽  
Pavement Temperature

Road and highway maintenance is vital for the safety of citizens and for enabling emergency and security services to perform their essential functions. Accumulation of snow and (or) ice on the pavement surface during the wintertime substantially increases the risk of road crashes and can have negative impact on the economy of the region. Recently, road maintenance engineers have used pavement surface temperature as a guide to the application of deicers. Stations for road weather information systems (RWIS) have been installed across Europe and North America to collect data that can be used to predict weather conditions such as air temperature. Modelling pavement surface temperature as a function of such weather conditions (air temperature, dew point, relative humidity, and wind speed) can provide an additional component that is essential for winter maintenance operations. This paper uses data collected by RWIS stations at the City of Ottawa to device a procedure that maximizes the use of a data batch containing complete, partially complete, and unusable data and to study the relationship between the pavement surface temperature and weather variables. Statistical models were developed, where stepwise regression was first applied to eliminate those variables whose estimated coefficients are not statistically significant. The remaining variables were further examined according to their contribution to the criterion of best fit and their physical relationships to each other to eliminate multicollinearities. The models were further corrected for the autocorrelation in their error structures. The final version of the developed models may then be used as a part of the decision-making process for winter maintenance operations.Key words: winter maintenance, pavement temperature, statistical modelling, RWIS.

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