Search results for "Civil Engineering"
showing 10 items of 1216 documents
Green Synthesis, Molecular Characterization and Associative Behavior of Some Gemini Surfactants without a Spacer Group.
2013
A series of new gemini surfactants without a spacer group, disodium 2,3-dialkyl-1,2,3,4-butanetetracarboxylates, were synthesized in a green chemistry context minimizing the use of organic solvents and applying microwaves (MW) when activation energy was required. Once the desired architecture was confirmed by means of the nuclear magnetic resonance technique (1H-NMR, 1H-1H COSY) for all the studied surfactants, the critical micellization concentration was determined by conductance measurements. The diffusion coefficient of micelles formed by the four compounds was characterized using pulsed field gradient (PFG)-NMR. Diffusion coefficients were found to be dependent on the concentration and …
The household location in multicenter urban spaces
1991
In multicenter urban spaces, the household location problem is to find an optimal location taking into account the locations of several economic centers.In this article, we show that the usual model, maximizing a residential utility under a budget spatial constraint, can’t give a satisfactory solution.So, we construct a fuzzy spatial model, including imprecision in consumer’s behavior. This model allows us to find an optimal location in a multicenter urban setting. Then, an empirical study illustrates the performances of the fuzzy model.
Using GIS for management of conflicts in natural protected area in Cindrel mountains
2021
This study reflects the possibility of using the GIS technology for the management and resolution of conflicts between stakeholders in the management of protected natural areas that cover large surfaces, such as Natura 2000 sites. The research is accomplished in Frumoasa site from Cindrel Mountains, where a conflict of a legal nature was analysed, in the extinguishment of which the technology of geographical information systems was used. In this sense, the presence of the species and habitats that are found on the surface of the incriminated forest was analysed and the comparison with the list of species and habitats that was the basis for declaring the surface as a nature 2000 site. In the…
Optimized Handover Algorithm Based on Stackelberg Games in CBTC Systems for Urban Rail Transit
2014
Communications Based Train Control (CBTC) systems have become indispensable for train operation to improve the safety and efficiency of train running to the utmost extent at present. In this paper, the problem of train handover in wireless LAN of CBTC systems for urban rail transit was taken into consideration, which was formulated as a market competition with Stackelberg games and cooperative diversity to obtain the reasonable resource allocation for trains. Under the environment of continuous train-to-wayside communications with high reliability, the successful train handover probability was analyzed in detail. Firstly, the relay triggering during handover was introduced, and the price st…
Considerations Regarding the Analysis and Interpretation of Traumatic Lesional Mechanisms in Road Accidents
2021
According to statistics, road transportation is the most dangerous means of transportation and also the costliest in terms of human lives and material damage. The increase of road safety is a priority goal of the European Commission and an area of high interest for Romania, which is unfortunately placed very high in the hierarchy of countries with a high number of deaths resulting from road accidents. This study presents the mechanisms of the generation of traumatic injuries and also analyses the manner of interpreting these mechanisms in the case of road accidents, both from the perspective of law enforcement and from the perspective of specialists in road transportation, who analyse and i…
First hints of pressure waves in a helical extragalactic jet: S5~0836+710
2014
One of the open questions in extragalactic jet Astrophysics is related to the nature of the observed radio jet, namely whether it traces a pattern or the flow structure itself. In this paper I summarize the evidence collected for the presence of waves in extragalactic jets. The evidence points towards the peak of emission in helical jets corresponding to pressure-maxima of a wave that is generated within the core region and propagates downstream. Making use of a number of very long baseline interferometry (VLBI) observations of the radio jet in the quasar S5~0836+710 at different frequencies and epochs, Perucho et al. (2012) were able to observe wave-like behavior within the observed radio-…
Shear design of high strength concrete beams in MRFs
2019
This paper presents the criteria for the shear design of high strength concrete (HSC) beams in moment resisting frames (MRFs). The formulation of an analytical model is provided for the case of beams with longitudinal reinforcement in the presence of transverse stirrups. The model is of additive type, in the meaning that the shear resistance of the beam is evaluated as the sum of several contributions. In particular, the contribution of concrete, longitudinal rebars, and transversal reinforcement are taken into account. Furthermore, for assessing the concrete contribution, a classical approach is followed, according to which two effects arise in the shear mechanism: the arc and the beam eff…
Some considerations on adapting academic qualifications to the Romanian labor market
2017
The paper presents the results of some research carried out by the authors during the activities of the “Academic Entrepreneurial Laboratory – Progress through Innovation and Practice – (Univers Practic)” and seeks to evince certain key aspects pertaining to the adaptation of university qualifications to the needs of the Romanian workforce. First, the general context of higher education and the current state of affairs, as reflected by the analysis of relevant works in the field are presented. This is followed by a presentation of the main results of a questionnaire-based study that evinces the opinions of students, graduates, and company managers with regard to the necessity of adapting ac…
Deep and Meaningful E-Learning with Social Virtual Reality Environments in Higher Education: A Systematic Literature Review
2021
Deep and meaningful learning (DML) in distant education should be an essential outcome of quality education. In this literature review, we focus on e-learning effectiveness along with the factors and conditions leading to DML when using social virtual reality environments (SVREs) in distance mode higher education (HE). Hence, a systematic literature review was conducted summarizing the findings from thirty-three empirical studies in HE between 2004 (appearance of VR) and 2019 (before coronavirus appearance). We searched for the cognitive, social, and affective aspects of DML in a research framework and studied their weight in SVREs. The findings suggest that the use of SVREs can provide aut…
Development of a conceptual model of sustainable building from a university
2021
Introduction: In this paper, the authors aim is to develop a conceptual model that aims to facilitate the processes of implementing sustainability and / or assessment of sustainable performance in a Higher Education Building (HEB). The conceptual model could also be used to compare two or more buildings of higher education in terms of sustainability. Methodology: The authors started the scientific research with the literature review in order to identify and analyze the most relevant aspects that are frequently assess and could influencing the components of sustainability in higher education institutions. These aspects were clustered into categories and for each of them were established obje…