scholarly journals Critical Gap Comparison between One-, Two-, and Three-Lane Roundabouts in Qatar

2020 ◽  
Vol 12 (10) ◽  
pp. 4232
Author(s):  
Khaled Shaaban ◽  
Hassan Hamad

A critical gap value of a roundabout is mainly affected by the interactions between the circulating vehicles and vehicles entering the roundabout. These interactions are impacted by many factors, including the number of circulating lanes, the aggressiveness of local drivers, vehicle types, and the number of approaching lanes. Therefore, it is essential to locally investigate critical gap values before conducting any studies to improve capacity and delay at roundabouts. The purpose of this study is to measure and compare the critical gap values for different types of roundabouts in Qatar. More than 10,000 measurements were collected. The results showed that the critical gap values were 2.24 s, 2.55 s, and 2.40 s for the one-, two-, and three-lane roundabouts, respectively. These values are also quite low when compared to values calculated in other countries, which can be an indication of driver aggressiveness and risky behavior. The study is one of the first efforts to compare three types of roundabouts and to understand the difference in operation between them in this region. The results of this study can help engineers, planners, and public agencies to plan, study, and design similar facilities.

2020 ◽  
Vol 12 (9) ◽  
pp. 3858 ◽  
Author(s):  
Magda Sibley ◽  
Antonio Peña-García

This paper presents the first comparative study of its type of the performance of light pipes with different types of apertures: a flat glass versus a bohemian crystal dome. Measurements were taken at 20-minute intervals over a period of one year in the bathrooms of two newly built identical houses of the same orientation located in Manchester, UK. The comparative analysis of the data collected for both light pipes types reveals that the crystal domed aperture consistently outperforms the flat glass one. Furthermore, the difference in the recorded horizontal illuminance is most marked during the winter months and at the end of the one-year experiment, indicating that the crystal dome has better performance for low incident winter light and higher resistance for the long term effect of weathering and pollution. This study provides strong evidence based on long term real measurements. Such evidence informs architects’ decisions when weighing up the aesthetic considerations of a flat glass aperture versus the higher illumination levels afforded by a crystal dome aperture with higher resistance to weathering and pollution.


2014 ◽  
Vol 8 (2) ◽  
Author(s):  
Simone Elisabeth Lang

AbstractIn describing the position of the narrator, research in literary studies generally follows Gérard Genette’s pioneering theory of narrative in distinguishing between the homo- and heterodiegetic type of narrator. This categorization is not sufficient to allow the position of the narrator to be described properly. The different ways in which the terms are used in literary studies reveal a shortcoming in the distinction behind them. Even in Genette’s work, there is a contradiction between the definition and the names of the two categories: Genette defines homo- and heterodiegesis with reference to the narrator’s presence in the narrated story, whereas he elsewhere states that the diegesis (in the sense of FrenchThe present article aims to do just that, starting from a theoretical standpoint. Thus, the different types of narrator that are possible are sketched in outline, and then explained with the help of examples.I begin by exposing the problems that result from using the terms in Genette’s manner (1), in order then to develop a list of possible narratorial standpoints based on the one hand on the involvement of the narratorial instance in the narrated world and on the other on its involvement in the story. By establishing separation of the two aspects as a ground rule in this way, a number of misunderstandings that are due to the varied ways in which the terminology has been used to date can be overcome.There follows a description of those cases that are unambiguously hetero- and homodiegetic (2), after which the problematic cases are considered (3), yielding the different types of homodiegetic narration that are possible. This latter set of distinctions will, like the others, shed light on the contours of the different narratorial positions and thus be capable of being put profitably into practice in textual interpretation. Accordingly, what is suggested is a way of using the terms that is first unambiguous and second beneficial to the interpretation of works, thus doing justice to the heuristic importance of narratology (see Kindt/Müller 2003; Stanzel 2002, 19).Thus, whereas the concept of diegesis provides the foundation for a distinction based on an ontological criterion that divides homo- and heterodiegesis from each other, the relationship between story and narrator is used to describe various types of homodiegetic narration. In the process, there come to light two types that are distinguished from each other by involvement in events (›homodiegetic, in the story‹ and ›homodiegetic, not in the story‹ narrators). If the narrator is not involved in events, the question arises of whether it would in principle have been possible for him to be involved in events, which is the norm with ›homodiegetic, not in the story‹ narrators, or whether a physical impossibility is the reason for his lack of involvement in the story. A special case of the ›homodiegetic, not in the story‹ narrator can be derived from this: peridiegetic narration: whereas narratorial instances of the ›homodiegetic, in the story‹ and ›homodiegetic, not in the story‹ types could in principle have been involved in the action and those of the ›homodiegetic, in the story‹ type actually were, peridiegetic narrators are marked by the fact that they cannot have been involved in the events.In summary, it will be shown that the concept of homodiegesis – in particular in the form in which it has previously been used, where links with the action and appearance in the story were not kept distinct – is in effect an umbrella term that brings together a number of possible forms. There is a prominent distinction between the ›homodiegetic, in the story‹ and the ›homodiegetic, not in the story‹ types of narrator (these types are represented in the present article by the old lawyer in Leo Perutz’s »The Beaming Moon« and the narrator who is a friend of Nathanael in E. T. A. Hoffmann’s »Sandman« respectively). The different degrees of homodiegetic narrator, which have often been mentioned in previous research and are defined by the strength of the character’s presence in the narrated world (from an uninvolved witness to an autodiegetic protagonist), are also to be situated between these two poles.It will also be shown in the process that the case of the narrator who is, for reasons of physical difference, not involved in events (the peridiegetic narrator) should be treated as a form of homodiegesis (for instance the schoolmaster in Theodor Storm’s


Author(s):  
Hilary B. Moore

There are two types of ground at Port Erin, differing widely in the general environmental conditions, and each with a characteristic type of urchin on it. The difference is sufficiently well marked for the local fishermen, who collect the urchins for sale to summer visitors, to distinguish them as different types. The littoral urchins from the Breakwater are larger and thicker shelled than those from the Breast. Their gonads reach a greater maximum size, and, in fact, never fall as low even as the maximum volume for the Breast urchin gonads. This difference is probably correlated with the much greater food supply on the Breakwater, since the gonad is the one organ of the body in which the animal can store reserve food material. Spawning commences in March or April and lasts for about two months, but is slightly earlier on the Breakwater than on the Breast. Ripening also takes place considerably earlier in both sexes on the littoral ground. Spawning seems to set in at a temperature of about 7° C., and the colder winter of 1931, compared with 1932, was associated with a later ripening and spawning, i n the former year. Similarly it is suggested that the slightly later spawning on the Breast than on the Breakwater is correlated with the slightly later rise in the temperature of the water on the deeper water ground in the spring.


2021 ◽  
Vol 263 ◽  
pp. 04011
Author(s):  
Evgeny Alekseev ◽  
Svetlana Shambina

The widespread use of reagent coagulation in the technology of purification of natural and waste waters is due to the complexity of the chemical composition and phase-dispersed state of the aqua systems of these waters, on the one hand, and the multifactorial action of coagulants on them, on the other. The mechanisms of interaction between coagulants and pollutants of wastewater which are in different phase-dispersed states include the physicochemical phenomena of coagulation, heterocoagulation, adagulation and sorption. The physicochemical concept “coagulation” reflects only one mechanism of coagulants’ action on pollutants. This leads to the appearing of the problem in terminological description of the physicochemical processes’ combined action when adding coagulants to the water being cleaned. The purpose of the study is to justify the use of universal indicators characterizing the multifactorial nature of the coagulation process, its formalization and quantitative assessment. The solution of the problem is to use the concept of “coasorption”, which determines the multifactorial nature of the interaction between coagulants and pollutants, and to use the technological indicator “specific coasorption”, which establishes a quantitative relationship between the pollutants’ indicators and the dose of coagulant. The test coagulation’s results of two different types of synthetic dyes’ solutions using aluminum salts reflect the difference in the mechanisms of their interaction with the coagulant. The formula for coasorption isotherm can be used to determine the required doses of reagents for coagulation of water basing on the initial and residual content of pollutants in the purified waters.


Author(s):  
Milica Čolović ◽  
Aleksandar Gadžić ◽  
Radovan Ilić ◽  
Marko Petrović

The main aim of this research is to investigate the relationship between the characteristic ways of overcoming the midlife crisis and the various ways of fatigue elimination. More precisely, to examine the correlation between denial by escape, denial by overcompensation, decompensation, and creative and successful coping with the crisis on the one hand and fatigue elimination with chemical stimulants, with psychological stimulation and with physical activity (PA) and active rest on the other, as well as the gender differences within these variables. The sample consisted of 300 middle-aged people, aged between 40 and 64, uniform by gender. The following instruments were used: A list of the respondents’ basic biodata, the Midlife Crisis Scale and an evaluation scale representing the basic techniques of fatigue elimination in participants from different categories specifically designed for the research. Since the score distribution on the tested variables statistically deviate from normal distribution, non-parametric techniques were used. Pearson's correlation coefficient was applied for determining the connection between variables and the Mann Whitney U test for testing the difference between the groups of participants. The obtained results show that there is a statistically significant correlation between adequate PA, as a way of fatigue elimination, and the creative and successful coping with the crisis, as well as a moderate connection between different types of passive rest and decompensation, especially in women. It can be concluded that moderate, well-prescribed, and age-appropriate PA, as an important form of active rest, is connected with the most optimal way of coping with a midlife crisis.


Author(s):  
Sandra Halperin ◽  
Oliver Heath

This chapter deals with the first step of the research process: the formulation of a well-crafted research question. It explains why political research should begin with a research question and how a research question structures the research process. It discusses the difference between a topic or general question, on the one hand, and a focused research question, on the other. It also considers the question of where to find and how to formulate research questions, the various types of questions scholars ask, and the role of the ‘literature review’ as a source and rationale for research questions. Finally, it describes a tool called the ‘research vase’ that provides a visualization of the research process, along with different types of questions: descriptive question, explanatory question, predictive question, prescriptive question and normative question.


2018 ◽  
Vol 7 (12) ◽  
pp. 480 ◽  
Author(s):  
Taras Agryzkov ◽  
Francisco Pedroche ◽  
Leandro Tortosa ◽  
José Vicent

Identifying the influential nodes in complex networks is a fundamental and practical topic at the moment. In this paper, a new centrality measure for complex networks is proposed based on two contrasting models that have their common origin in the well-known PageRank centrality. On the one hand, the essence of the model proposed is taken from the Adapted PageRank Algorithm (APA) centrality, whose main characteristic is that constitutes a measure to establish a ranking of nodes considering the importance of some dataset associated to the network. On the other hand, a technique known as two-layers PageRank approach is applied to this model. This technique focuses on the idea that the PageRank centrality can be understood as a two-layer network, the topological and teleportation layers, respectively. The main point of the proposed centrality is that it combines the APA centrality with the idea of two-layers; however, the difference now is that the teleportation layer is replaced by a layer that collects the data present in the network. This combination gives rise to a new algorithm for ranking the nodes according to their importance. Subsequently, the coherence of the new measure is demonstrated by calculating the correlation and the quantitative differences of both centralities (APA and the new centrality). A detailed study of the differences of both centralities, taking different types of networks, is performed. A real urban network with data randomly generated is evaluated as well as the well-known Zachary’s karate club network. Some numerical results are carried out by varying the values of the α parameter—known as dumping factor in PageRank model—that varies the importance given to the two layers (topology and data) within the computation of the new centrality. The proposed algorithm takes the best characteristics of the models on which it is based: on the one hand, it is a measure of centrality, in complex networks with data, whose calculation is stable numerically and, on the other hand, it is able to separate the topological properties of the network and the influence of the data.


Author(s):  
Tathagatha Khan ◽  
Adheesh Kumar Vivek ◽  
Smruti Sourava Mohapatra

Critical gap is a crucial factor for capacity estimation and safety evaluation at uncontrolled mid-block median openings (MBMOs). The U-turning vehicle makes a U-turn when a sufficient gap between two fast-moving vehicles is available in the approaching through traffic (ATT) stream. Even though, worldwide, temporal gaps are extensively used, the spatial gap is an important parameter that significantly affects minor street vehicles’ safety (U-turning vehicles in this study). The present research, undertaken in India, focuses on estimating the temporal and spatial critical gap of U-turning vehicles at uncontrolled MBMOs. The collected data were analyzed for six different types of U-turning vehicles at varying approaching through traffic volume (ATTV). For critical gap estimation, four different critical gap estimation techniques, namely, modified Raff method (MRM), Ashworth method, binary logit model (BLM) method, and occupancy time (OT) method were employed, separately. From the analysis, temporal and spatial critical gaps were observed to vary between different types of vehicle, and it was also observed to vary with ATTV. The critical gap values of this study were found to be smaller than the critical values reported in developed countries, signifying the aggressive driving nature of drivers in developing countries. A detailed appraisal of the different critical gap estimation methods has been carried out. From this analysis, the OT method was found to provide the closest critical gap values with the published literature compared with other methods. Lastly, the findings from the present study will be useful for capacity estimation and safety evaluation at MBMO.


2020 ◽  
Vol 65 (4) ◽  
pp. 189-208
Author(s):  
Katharina Gerhalter ◽  
Stefan Koch

Adverbials with Adjectival Basis in Brazilian Portuguese and Their Frequency in Spoken and Written Language. The present paper focuses on the use of adverbs with an adjectival lexical base in spoken and written present-day Brazilian Portuguese. We compare the frequencies of three different types of adverbials: adverbs in mente (e.g. absolutamente), adjective-adverbs (e.g. alto in falar alto ‘speak loudly’) and prepositional phrases with adjectives as the post-prepositional element (e.g. de novo), the latter being the main focus of this study. The analysis is based on the Discurso & Gramática-corpus, which consists of oral interviews of 170 informants and their written texts on the same topic as the one in the interviews. The data shows that prepositional phrases are less frequent (in terms of type and token frequency) than adjective-adverbs and adverbs ending in mente. Regarding the difference between spoken and written language, adverbs in mente occur remarkably more often in written texts while adjective-adverbs are more frequent in spoken language. Prepositional phrases, instead, occur equally in both codes. Finally, we draw the conclusion that prepositional phrases form a small but stable inventory of lexicalised forms, which are not marked for any code.


1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.


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