1,720,963 research outputs found
Etude de La vulnérabilité à la pollution chimique des eaux souterraines (ZNS) de la région d’Ouargla, Sud-Est Algérien
No full textDans la cuvette d’Ouargla, la pollution des eaux souterraines est un sujet qui inquiète les habitants et les autorités. Ce travail consiste à étudier les causes de pollution des eaux souterraines (ZNS). Nous avons procédé à l’échantillonnage puis à l’analyse, sur site et au laboratoire, de plusieurs puits de la cuvette, afin d’aboutir a une base des données pour résoudre les problèmes qui caractérisent cette dernière. D’après les analyses des eaux souterraines nous avons traité la vulnérabilité des eaux de la cuvette à la pollution ; la carte d’évolution de l’indice de pollution est d’une importance capitale pour la protection contre la pollution
Influence of Natural Fractures on Oil Production of Unconventional Reservoirs
No full textAbstractIn recent years, awareness of the role of fractures on the production and recovery of hydrocarbons has become increasingly strong in the oil community.To shed light on this question, this paper examines the fractures characterization and their effects on production and enhanced oil recovery; also, it deals with characterization of specific features of fractured reservoirs, using different tools as cores analysis and 3D imagery.The effect of fractures on well productivity is explained and in this point, we have taken the data of wells production from a single reservoir to put these wells at the same overburden conditions. We have selected as example “El Gassi” field to follow the evolution of gas/oil ratio (GOR) according to wells daily production.To analyze the effect of the injection on the daily production of the field, we have compared the evolution of the production of three tanks, two fractured reservoirs and a third non-fractured (consolidated). We took the “El Gassi” and “Rhourde El Bagel” fields as fractured reservoirs, and “Hassi Berkin” field as consolidated one. Then we have treated the impact of fractures on assisted oil recovery; we have studied the response of production at “Rhoud El Bagel” field after gas injection.Data analysis of the production of these three Algerian fields shows that there is no direct apparent relationship between the intensity of fractures and average production. A change in the recovery mode is required by the orientation to water injection or water alternating gas “WAG” process
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Surface water and groundwater quality assessment using the WQI method and human health risk assessment (HHR) in the lower seybouse (Annaba Plain), northeast Algeria
No full textThis study was carried out to investigate the current status of surface water and groundwater quality in Lower Seybouse and Annaba Plain, NE Algeria. 36 surface water and groundwater samples were collected in this area, and various physicochemical parameters were analysed. The quality of surface water and groundwater for drinking and the associated health risks were assessed using a Water Quality Index (WQI) and a Human Health Risk Assessment (HHRA) model. The results show that all samples are alkaline with the EC values ranging from 1139 to 5555 μS/cm. The ionic dominance pattern was in the order of Na+ > Mg2+ > Ca2+ > K+ for cations and Cl– > HCO3 – > SO4 2 – > NO3 – for anions, respectively. The dominant water types are SO4-Cl-Ca-Mg and SO4-Cl-Na, formed by dissolution of evaporative and carbonate-rich material. All samples are unsuitable for drinking, with 1 sample classified as poor (rank = 4) and 35 samples as extremely poor (rank = 5). These samples are mainly located near the Seybouse Wadi, which is a natural outlet for wastewater from human activities. The assessment of non-carcinogenic risk showed that the Hazard Index (HI) for males ranged from 0.12 to 1.01 with a mean of 0.30 and only one sample exceeded value 1. For females, the HI was between 0.16 and 1.28 for females, with a mean of 0.39. The risk for children was even higher, ranging from 0.41 to 3.28, with a mean of 1.03, suggesting that children are more vulnerable to water contamination. The Carcinogenic Risk (CR) values for Pb ranged from 10–3 to 8.6 · 10–3, with a mean of 2.6 · 10–3 for males, and between 1.4 · 10–3 to 10–2, with a mean of 3.3 · 10–3 for females, while for children the CR values ranged from 3.5 · 10–3 to 2.7 · 10–3, with a mean of 8.4 · 10–3, indicating that no possible CR from water drinkin
Study of Mineral and Organic Pollution of the Unsaturated Zone (UZ) of the Bowl Ouargla, Southeast Algerian.
No full textAbstractIn the bowl of Ouargla, pollution of groundwater is the main topic that worries people and authorities. This work is to study the causes of groundwater pollution (UZ). We conducted sampling and analysis on site and in the laboratory, the number of wells in the basin in order to achieve has a database to solve the problems which characterize the latter. Based on analyzes of groundwater vulnerability we treated water bowl pollution, map the evolution of the pollution index is of utmost importance for the protection against pollution
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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