1,356 research outputs found

    ETUDE DE L’ISOTHERME 25 °C DU SYSTEME QUASI QUATERNAIRE H2O - Zn(NO3)2,6H2O – Cu(NO3)2,3H2O - NH4NO3 II- ISOPLETHES : 41 MASSE % Cu(NO3)2, [MASSE DE NH4NO3] = -10/9 [MASSE DE Zn(NO3)2] + 100, [MASSE DE H2O] = 0.5702 [MASSE DE ZN(NO3)2] + 0.2879[ MASSE DE

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    The solid-liquid equilibria of the quasi quaternary system H2O Zn(NO3)2,6H2O Cu(NO3)2,3H2O-NH4NO3 were studied at 25°C by using a synthetic method based on conductivity measurements. Three isoplethic sections has been established at 25°C and the stable solid phases which appear are: NH4NO3 (IV), Zn(NO3)2,6H2O, Cu(NO3)2,3H2O and metastable Cu(NO3),2.5H2O. Neither double salts, nor mixed crystals are observed at these temperature and composition range

    Vulnerability analysis of satellite-based synchronized smart grids monitoring systems

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    The large-scale deployment of wide-area monitoring systems could play a strategic role in supporting the evolution of traditional power systems toward smarter and self-healing grids. The correct operation of these synchronized monitoring systems requires a common and accurate timing reference usually provided by a satellite-based global positioning system. Although these satellites signals provide timing accuracy that easily exceeds the needs of the power industry, they are extremely vulnerable to radio frequency interference. Consequently, a comprehensive analysis aimed at identifying their potential vulnerabilities is of paramount importance for correct and safe wide-area monitoring system operation. Armed with such a vision, this article presents and discusses the results of an experimental analysis aimed at characterizing the vulnerability of global positioning system based wide-area monitoring systems to external interferences. The article outlines the potential strategies that could be adopted to protect global positioning system receivers from external cyber-attacks and proposes decentralized defense strategies based on self-organizing sensor networks aimed at assuring correct time synchronization in the presence of external attacks

    MODELING OF THE INFLUENCE OF THERMIC TREATMENT UPON THE MECHANICAL PROPERTIES OF ALUMINUM-TIN ALLOYS

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    In order to master and improve the quality and properties of the final products, the major industrial challenge lies in the possibility of controlling the morphology, size of microstructures that reside within the molded pieces, as well as their defects; this is the fundamental reason according to which we are more and more interested in mastering the growth and germination of such alloys, as well as the developing structures, at the time of solidification process. The modeling reveals as a valuable aid in the mastery of the formation of such heterogeneousness: segregation cells that are incompatible with industrial requirements. The whole work focuses upon the modeling of the segregation phenomenon of the four hypoeutectic alloys, Al1%Sn, Al2%Sn, Al3%Sn and Al4%Sn, as well as the tin effect upon certain mechanical properties of aluminum. Usually, the microstructure and mechanical behavior of such alloys as Al-Sn are directly influenced by some parameters such as composition, cooling velocity and homogenization process

    Developmental trends in voice onset time: some evidence for sex differences

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    This study reports on an investigation into the voice onset time (VOT) patterns of the plosives /p b t d/ in a group of 30 children aged 7 (n = 10), 9 (n = 10) and 11 (n = 10) years. Equal numbers of girls and boys participated in the study. Each child named a series of letter objects to elicit /p b t d/ in a syllable onset position with a fixed vowel context. VOT data were examined for age, sex and plosive differences with the following hypotheses: Firstly, that there would be sex differences in the VOT patterns of preadolescent children. Secondly, that the sex differences in VOT patterns would be linked to age and development, and that these would eventually become marked by the age of 11 years, by which time adult-like VOT values should have been achieved. Finally, that the extent of sex and age differences would be dependent upon the plosive being investigated. Results indicated patterns of decrease with age in the VOT values of /p b/ for the boys, with some evidence of increases in the VOT values of /t/ for the girls. In addition, 'voiced' and 'voiceless' cognates showed a more marked bimodal distribution in the girls' VOT patterns. This bimodal distribution was investigated by examining the degree of difference between the VOT values of voiced and voiceless cognate pairs /p b/ and /t d/, and examining the effects of age, sex and cognate pair. These results indicated that more marked sex differences in the 'voiced'/'voiceless' contrast emerged between the data of the 9- and 11-year-olds, a pattern, which was more marked for the alveolar plosives. These preliminary results confirmed all three hypotheses. The findings are presented and discussed both within a developmental and sociophonetic framework

    Managing Forest Conflicts: Perspectives of Indonesia's Forest Management Unit Directors

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    Recent expansion of the forestry and plantation sectors in Indonesia has intensified agrarian and natural resource conflicts, and created increased awareness of the social, economic and environmental impacts of these disputes. Addressing these disputes is a critical issue in advancing Indonesia's commitment to sustainable forest management. The Forest Management Units (Kesatuan Pengelolaan Hutan, or KPH), have become the pivotal structural element for managing all state forests at the local level, with responsibility for conventional forest management and policy implementation (establishing management boundaries, conducting forest inventory, and developing forest management plans), as well as the legal mandate to communicate and work with indigenous people and local communities. This paper presents the results of a national survey of all currently functioning KPH units, the first of its kind ever conducted with KPH leadership, to obtain a system-wide perspective of the KPHs' role, mandate, and capacity for serving as effective intermediaries in managing forest conflicts in Indonesia. The survey results show that the KPHs are still in a very initial stage of development, and are struggling with a complex and rapidly evolving policy and institutional framework. The most common conflicts noted by respondents included forest encroachment, tenure disputes, boundary conflicts, and illegal logging and land clearing. KPH leadership views conflict resolution as among their primary duties and functions, and underscored the importance of more proactive and collaborative approaches for addressing conflict, many seeing themselves as capable facilitators and mediators. Overall, these results juxtapose a generally constructive view by KPH leadership over their role and responsibility in addressing forest management conflicts, with an extremely challenging social, institutional, and political setting. The KPHs can certainly play an important role as local intermediaries, and in some cases, as facilitative mediators in resolving local conflicts, but only with a more concerted effort from central and provincial government authorities to provide greater consistency in policies and regulations, improved policy communication, and a sustained commitment to strengthening the capacity of individual KPHs

    Uncertainty in pore size distribution derived from adsorption isotherms: I. classical methods

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    Procedures for propagation of uncertainty in pore size distribution calculation based on classical methods for both micro and mesoporous materials are described. Uncertainty in experimental adsorption isotherm data and uncertainty in temperature are introduced as the main sources for uncertainty in height and position of peaks of PSD determined via classical mesopore size distribution determination method. Uncertainty in PSD derived from classical micropore size distribution methods mainly arises from uncertainty in experimental isotherm data. Calculation step size is shown to have some effects on magnitude of uncertainty in micropore calculation. Micropore size distribution calculations are also highly sensitive to the adsorptive molecular diameter

    Entretien des cathéters à chambres implantables

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    Le cathéter à chambre implantable (CCI) est un dispositif sous cutané relié à une voie centrale par l’intermédiaire d’un cathéter. La ponction de ce dispositif sous cutané permet ainsi un accès direct à la voie centrale. Une fois mise en place, le CCI peut être portée pendant des années permettant ainsi des utilisations multiples. Les CCI, utilisés depuis une vingtaine d’années, se sont avérés indispensables dans la prise en charge des patients nécessitant des traitements répétés et de longue durée. En effet, ils peuvent être utilisés pour des prélèvements sanguins, des perfusions, des transfusions et l’administration de médicaments. Ce dispositif a l’avantage de préserver le capital veineux du patient et d’assurer un confort pour le malade et pour le personnel médical. Cependant, l’utilisation de ce dispositif doit se faire avec le maximum de précautions afin de prévenir d’éventuelles complications. Ceci sous entend une maîtrise des techniques de manipulation des CCI et une connaissance parfaite des incidents et accidents possibles et de leur prise en charge. Nous allons d’abord traiter la technique de ponction des CCI et aborder par la suite les complications les plus fréquentes et leur prise en charge

    Impact of body composition analysis on male sexual function: A metabolic age study

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    Introduction: Metabolic Age (MetAge) and body composition analysis may reflect an individual’s metabolic status, which is believed to influence male sexual and gonadal functions. Although erectile dysfunction (ED) and hypogonadism are increasingly prevalent with age, they are also detected among younger men. This study aims to assess the impact of MetAge and body composition on male sexual and gonadal status overall, and particularly in men younger than 40 years of age. Methods: This was a cross-sectional study of 90 male healthcare workers, between the ages of 18-55, randomly selected based on their corporation numbers. In addition to Bioelectric Impedance Analysis, subjects were requested to fill the International Index of Erectile Function questionnaire (IIEF-5) and to provide an early morning serum testosterone (T) sample. Results: The mean participants’ age was 39.4 ± 9.4 years, MetAge was 45.54 ± 10.35 years, serum T level was 13.68 ± 4.49 nmol/L and BMI was 28.8 ± 4.7 kg/m2. Significant negative correlations were obtained between serum T, MetAge, body weight and fat composition. Significant negative correlations between the IIEF-5 score, MetAge, and fat composition, were only reported in subjects <40 years of age. Significantly lower T levels (p=0.002), significantly older MetAge (p=0.034), and higher BMI (p=0.044) and degree of obesity (p=0.042) were observed in participants <40 years with erectile dysfunction (ED) compared to their counterparts without ED. Discussion: MetAge and body composition parameters significantly impact the androgenic state. ED in men <40 years is associated with lower T levels, older MetAge and higher BMI and degree of obesity

    INFLUENCE DU TRAITEMENT THERMIQUE ET MECANIQUE SUR LES PROPRIETES MECANIQUES ET STRUCTURALES DES ACIERS AU MANGANESE MOULES.

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    Molded Steel with manganese have approximately 1,2% C and 12% Mn, this high proportion of manganese gives to this alloy a stable austenitic structure on a room temperature. The experimental methods used for metallurgical studies are spark optical emission spectroscopy, optical microscopy, scanning electron microscopy, micro-hardness and hardnesss test. Steel 1 is heat-treated constitued by 15,516 % of manganese, 2,677 % of chromuim and 1,286 % of carbon. Steel 2 is mechanically treated contains 13,454 % of manganese, 1,721 % of chromuim and 1,213 % of carbon . Steel 1 has sustained quench at 1070°C, for two differents maintaining times on oven 30 and 50 minutes for a thickness of 150 millimeters then for two differents thickness 100 and 150 millimeters for a time of 50 minutes. When maintaining time on the oven increase for low dimension, surface’s alloy become more ductile. We have applied a mechanical treatement manually on steel 2 surface, his hardness increase significantly

    Intelligent Passive Anti-Islanding Protection for Doubly Fed Induction Generators

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    Abstract The integration of wind generation units into power system introduces several issues including islanding operation
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