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  • Author: Andrei Radu x
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Abstract

Arch bridges are slender structures and can be efficiently used in the range of medium to large spans. These structures have an improved aesthetic aspect and in the same time a low construction height, with obvious advantages regarding reduced costs in the infrastructuers and their foundations.

For this type of structures usually composite or orthotropic decks are used. Lately, innovative solutions have been used in designing arch bridges, especially discarding the top wind bracing system. The level of axial forces and bending moments in the arches and tie imply the design of sections with sufficient stiffness and strength in both directions in order to ensure the general stability of the arches, without the need for top wind bracing. Moreover, the cross section of the arches is not constant, but shifts in accordance with the variation of the bending moments, in order to ensure their lateral stability.

This paper studies a road bridge with parallel Bowstring arches, with a span of 108m and a carriageway 7.00m wide, sustained by a deck made up of crossbeams 2m apart and a concrete slab. The main beams are held by ties arranged in the Langer system, 10 to 14m apart from each other. The sag of the arches is 18m high.

The analyzed structure was proposed for construction in the city of Oradea and is used for crossing the “Crişul Repede” river, between Oneştilor street on the left bank and the Sovata, Fagului and Carpaţi streets on the right bank.

The performed analyses have the following two main objectives: to establish the critical load for which the failure of the arches occurs by instability and to underline the influence of different wind bracing systems on the bridge’s collapse loads respectively.

Abstract

During the last years, in Romania and Bulgaria, an acceleration of existent disparities took place compared to the European Union countries as regards the occupational labor structures and an decreased evolution of the active population migration to other EU states. Starting from these considerations, the present paper shows an analysis of general and specific aspects of the labor market in the two neighbouring countries, starting from the general analysis, at national level, continuing with the regional analysis until the local analysis of the labor market, at cross border level. In Romania, in 2016, an employment rate of the population at work age (15-64 years old) was of 61.6%, to an active population of 8,979 thousand persons, of which 8,449 thousand employed persons and 530 thousand were unemployed. In Bulgaria, in 2016 the active population was of 3,264 thousand persons, respectively, 53.3%, of which 3,199.6 thousand employed persons and 64.4 thousand unemployed. The employment rate of the work was of 68.7%.. There are still signs that in the two countries the legislation complies to the realities and needs in practice.

Abstract

Accounting it’s an important component of the economic information system. E. Horomnea believes that through specific means and procedures, accounting provides: clarifications of the past and the present of the economic entities, pertinent analyzes that are directed to the market; provides guidance on the strategic future; provides motivations and solutions for the decisions made. This article will analyze the evolution of managerial accounting from traditional costing to the new guidelines, when the issue of creating added value and managing third parties needs represents the future of any information system. After 1987 there are continuous changes and concerns, not only at Romanian level but at world wide scale.

Abstract

Wireless mobile telecommunications are of growing importance and an enabler for the Internet of Things. Most networks are IP based or moving to an IP based infrastructure, including the latest 4G LTE and the future 5G networks. Understanding and being able to predict the behavior and performance of such networks in various scenarios and conditions is critical. This drives the need to study IP impairments in wireless telecommunications networks and to assess their impact on network and service performance. One method is to emulate/generate IP impairments while observing and measuring their impact on network performance. In this paper the authors analyze the challenges associated with analyzing the behavior of mobile wireless networks. They discuss the importance and benefits of IP impairments testing and mention the high cost of dedicated IP impairment emulators for telecommunications. A flexible and affordable solution is proposed for educational purposes and the study of IP impairments on wireless telecommunication networks.

Abstract

This article introduces the topic of armed non-state actors and briefly summarizes the contributions to this special issue.

Abstract

Introduction

Five-minute heart-rate variability (HRV) measurement is a useful tool for assessing the autonomic nervous system (ANS) balance in humans, but there are no studies on healthy dogs. The aim of the study was, therefore, to provide the reference ranges in small and medium-sized breeds for short-term HRV time and frequency domain (TFD) analyses.

Material and Methods

A total of 79 healthy dogs were included in the study between 2015 and 2019. Grouping by age with the breakpoint at six years and subgrouping by reproductive status and sex was imposed. All the dogs were included after physical and cardiological examinations and blood analyses. The TFD of HRV were analysed from a five-minute-long digital ECG recording after removal of non-sinus complexes.

Results

There were no statistically significant differences in any TFD parameters between age, reproductive status or sex groups. A mild increase in all time domain parameters and the high-frequency (HF) band was observed in older dogs, and the low frequency (LF):HF ratio decreased in these dogs. In males, the time domain parameters and HF band increased slightly.

Conclusion

The normal ranges for HRV derived from short-term ECG recording in the usual clinical environment now have proposed reference ranges. Our findings suggest that accommodation time, age, sex, or reproductive status do not influence the results derived from these recordings, indicating that this method is reliable for assessing the ANS function in small and medium-sized dog breeds.

Abstract

The sewage sludge from wastewater treatment plant of Iasi, a city with 300,000 inhabitants, for domestic and industrial origin, was stored in a mud pond arranged on an area of 18,920 m2. Chemical analyzes of the sludge showed that, of all the chemical elements determined, only Zn is found at pollutant level (5739 mg∙kg-1), i.e. almost 30 times more than the maximum allowable limit for Zn in soil and 45 times more than the Zn content of the soil on which the mud pond has been set. Over time, the content of Zn in the mud pond, but also from soil to which it has been placed, has become upper the normal content of the surrounding soil up to a depth of 260 cm. On the other hand, the vegetation installed on sewage sludge in the process of mineralization, composed predominantly of Phragmites, Rumex, Chenopodium, and Aster species had accumulated in roots, stems and leaves Zn quantities equivalent to 1463 mg Kg-1, 3988 mg Kg-1, 1463 mg Kg-1, respectively, 1120 mg∙Kg-1. The plants in question represents the natural means of phytoremediation, and sewage sludge as such may constitute a fertilizer material for soils in the area, on which Zn deficiency in maize has been recorded. In addition, the ash resulted from the incineration of plants loaded with zinc may constitute, in its turn, a good material for fertilizing of the soils that are deficient in zinc.

Abstract

This study aims to identify if there is a relation between postural balance and the accuracy of 7 meters throws in handball. There is an increase need to improve the success of the 7 meters throw, due to its impact regarding a win or loss over the past years during high-end competitions. Subjects: 173 subjects were involved in this study, 123 males and 50 females with the ages between 18 and 21 years old. Materials: We’ve conducted the balance test using the AMTI NETforce BP 400600 force platform and for the accuracy test we’ve conducted a shooting trial that quantified the spread of a series of throws from the 7 meters mark. We’ve observed the radial dislocation, area and length of the center of pressure for the balance test and for the shooting trial we’ve measured the distance of the throw from a preset spot. Results: There were no correlation between the important factors of balance like Dislocation, Area, Length, and throwing percentage for the Circle, Area 1, Area 2, Missed balls. Instead, between the 3 important factors of balance, there are strong and positive correlations, drawing the conclusion that when we have big numbers for center of gravity deviations, total trajectory (cm2) and the area values, the chances to score a goal from 7 meters are lower. Conclusions: The results of the study confirm the hypothesis. The objectives for a future study is to find ways/methods to improve the general balance, in order to increase the efficiency for the 7 meters throwing.

Abstract

The paper deals with the modal analysis and frequency response analysis of a bucket wheel excavator (BWE) boom, obtained by simulation, based on a virtual model of an existing BWE boom. The boom, which generally is realized as a spatial truss, is the most vulnerable subsystem of the BWE, being submitted to severe operational loads characterized by very pronounced cyclical, dynamic and stochastic variability. This vulnerability is the consequence of its shape and constructive parameters and the nature, source and character of the external exciting loads to which it is exposed. The classical approach recommended by standards and norms cannot predict the occurrence of failures caused by vibration, which produces fatigue due to the load’s cyclical variability and the deformation produced by resonant vibration of some constitutive elements. As exciting load we considered the operational forces acting on the bucket wheel. In this manner we can take into account the constructive features – with modal analysis, and the vibration regime – with frequency response analysis. The proposed method is useful both in the design phase of new load-bearing structures of truss type subjected to high-variability forces, and also in refurbishment or improvement phases of the existing structures of this kind.