scholarly journals Macrophytes as a tool for assessing the trophic status of a river: a case study of the upper Oum Er Rbia Basin (Morocco)

2021 ◽  
Vol 50 (1) ◽  
pp. 77-86
Author(s):  
Ayoub Nouri ◽  
Hammada Soumaya ◽  
Chillasse Lahcen ◽  
Haddioui Abdelmajid
Keyword(s):  
Trophic Level ◽  
Trophic Status ◽  
Biological Index ◽  
Hydrochemical Parameters ◽  
Abiotic Parameters ◽  
Macrophyte Species ◽  
Main Components ◽  
Very High ◽  
Lotic Waters

Abstract Macrophytes are one of the main components of the aquatic ecosystem. They are used in several countries as metrics for the ecological assessment of hydrosystems. The objective of our study was to evaluate the suitability of the Macrophyte Biological Index for Rivers (IBMR) to determine a trophic level in the upper Oum Er Rbia basin (Morocco) and to understand physicochemical parameters of water that govern the distribution of macrophyte species. CCA analysis was used to relate the distribution of macrophytes to hydrochemical parameters of water. The CCA analysis shows that the distribution of macrophytes was more correlated with abiotic parameters (EC, WT and DO) than nutrient parameters (PO4-P, NO3-N, NO2-N, NH3-N and CODMn). The recorded values of IBMR in the upper Oum Er Rbia basin indicate that the trophic level of the studied rivers ranged from “moderate” to “very high”. Pearson's correlation coefficient showed that the IBMR is more correlated with the abiotic parameters such as WT and EC and does not show any significant correlation with the content of PO4-P and NH3-N in water, which makes the IBMR index unreliable for assessing the trophic status related to phosphate and ammonia concentrations in our lotic waters.

scholarly journals Portable DC Supply Based on SiC Power Devices for High-Voltage Marx Generator

Electronics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 313
Author(s):  
Jacek Rąbkowski ◽  
Andrzej Łasica ◽  
Mariusz Zdanowski ◽  
Grzegorz Wrona ◽  
Jacek Starzyński
Keyword(s):  
High Voltage ◽  
Specific Area ◽  
Input Voltage ◽  
Marx Generator ◽  
Power Devices ◽  
Laboratory Setup ◽  
High Voltage Gain ◽  
Main Components ◽  
Two Stages ◽  
Very High

The paper describes major issues related to the design of a portable SiC-based DC supply developed for evaluation of a high-voltage Marx generator. This generator is developed to be a part of an electromagnetic cannon providing very high voltage and current pulses aiming at the destruction of electronics equipment in a specific area. The portable DC supply offers a very high voltage gain: input voltage is 24 V, while the generator requires supply voltages up to 50 kV. Thus, the system contains two stages designed on the basis of SiC power devices operating with frequencies up to 100 kHz. At first, the input voltage is boosted up to 400 V by a non-isolated double-boost converter, and then a resonant DC-DC converter with a special transformer elevates the voltage to the required level. In the paper, the main components of the laboratory setup are presented, and experimental results of the DC supply and whole system are also shown.

scholarly journals Influence of Hydrogeochemistry on Tunnel Drainage in Evaporitic Formations: El Regajal Tunnel Case Study (Aranjuez, Spain)

2021 ◽  
Vol 13 (3) ◽  
pp. 1505
Author(s):  
Ignacio Menéndez Pidal ◽  
Jose Antonio Mancebo Piqueras ◽  
Eugenio Sanz Pérez ◽  
Clemente Sáenz Sanz
Keyword(s):  
High Speed ◽  
Civil Engineering ◽  
Saturation Index ◽  
The Subject ◽  
Under Construction ◽  
Underground Flow ◽  
Very High ◽  
Over Time

Many of the large number of underground works constructed or under construction in recent years are in unfavorable terrains facing unusual situations and construction conditions. This is the case of the subject under study in this paper: a tunnel excavated in evaporitic rocks that experienced significant karstification problems very quickly over time. As a result of this situation, the causes that may underlie this rapid karstification are investigated and a novel methodology is presented in civil engineering where the use of saturation indices for the different mineral specimens present has been crucial. The drainage of the rock massif of El Regajal (Madrid-Toledo, Spain, in the Madrid-Valencia high-speed train line) was studied and permitted the in-situ study of the hydrogeochemical evolution of water flow in the Miocene evaporitic materials of the Tajo Basin as a full-scale testing laboratory, that are conforms as a whole, a single aquifer. The work provides a novel methodology based on the calculation of activities through the hydrogeochemical study of water samples in different piezometers, estimating the saturation index of different saline materials and the dissolution capacity of the brine, which is surprisingly very high despite the high electrical conductivity. The circulating brine appears unsaturated with respect to thenardite, mirabilite, epsomite, glauberite, and halite. The alteration of the underground flow and the consequent renewal of the water of the aquifer by the infiltration water of rain and irrigation is the cause of the hydrogeochemical imbalance and the modification of the characteristics of the massif. These modifications include very important loss of material by dissolution, altering the resistance of the terrain and the increase of the porosity. Simultaneously, different expansive and recrystallization processes that decrease the porosity of the massif were identified in the present work. The hydrogeochemical study allows the evolution of these phenomena to be followed over time, and this, in turn, may facilitate the implementation of preventive works in civil engineering.

scholarly journals A Raster-Based Subdividing Indicator to Map Urban Heat Vulnerability: A Case Study in Sydney, Australia

2018 ◽  
Vol 15 (11) ◽  
pp. 2516 ◽  
Author(s):  
Wei Zhang ◽  
Phil McManus ◽  
Elizabeth Duncan
Keyword(s):  
High Heat ◽  
The Past ◽  
Urban Heat ◽  
Research Gap ◽  
Heat Vulnerability ◽  
Very High ◽  
Flexible Model ◽  
General Indicator ◽  
Sydney Australia

Assessing and mapping urban heat vulnerability has developed significantly over the past decade. Many studies have mapped urban heat vulnerability with a census unit-based general indicator (CGI). However, this kind of indicator has many problems, such as inaccurate assessment results and lacking comparability among different studies. This paper seeks to address this research gap and proposes a raster-based subdividing indicator to map urban heat vulnerability. We created a raster-based subdividing indicator (RSI) to map urban heat vulnerability from 3 aspects: exposure, sensitivity and adaptive capacity. We applied and compared it with a raster-based general indicator (RGI) and a census unit-based general indicator (CGI) in Sydney, Australia. Spatial statistics and analysis were used to investigate the performance among those three indicators. The results indicate that: (1) compared with the RSI framework, 67.54% of very high heat vulnerability pixels were ignored in the RGI framework; and up to 83.63% of very high heat vulnerability pixels were ignored in the CGI framework; (2) Compared with the previous CGI framework, a RSI framework has many advantages. These include more accurate results, more flexible model structure, and higher comparability among different studies. This study recommends using a RSI framework to map urban heat vulnerability in the future.

scholarly journals Raman investigation of corrosion products on Roman copper-based artefacts

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 129
Author(s):  
Leila Es Sebar ◽  
Leonardo Iannucci ◽  
Yuval Goren ◽  
Peter Fabian ◽  
Emma Angelini ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Principal Components Analysis ◽  
Principal Components ◽  
Roman Period ◽  
Corrosion Products ◽  
Beer Sheva ◽  
Chemometric Technique ◽  
Components Analysis ◽  
Main Components

<p class="Abstract">This paper illustrates a case study related to the characterisation of corrosion products present on recently excavated artefacts. The archaeological findings, from the Rakafot 54 site (Beer-Sheva, Israel), consist of 23 coins and a pendant, all dating back to the Roman period. Raman spectroscopy was used to identify the corrosion products that compose the patina covering the objects. To facilitate and support their identification, spectra were then processed using principal components analysis. This chemometric technique allowed the identification of two main compounds, classified as atacamite and clinoatacamite, which formed the main components of the patinas. The results of this investigation can help in assessing the conservation state of artefacts and defining the correct restoration strategy.</p>

scholarly journals REVISITING THE LIFE STYLE OF THE DON FOREST-STEPPE BELT POPULATION DURING THE SCYTHIAN PERIOD (THE CASE STUDY OF THE KSIZOVO-19 CEMETERY)

2021 ◽  
pp. 129-144
Author(s):  
И. К. Решетова ◽  
М. В. Добровольская ◽  
А. Н. Меркулов
Keyword(s):  
Physical Activity ◽  
Stress Level ◽  
Life Style ◽  
Forest Steppe ◽  
Pathological Conditions ◽  
Steppe Belt ◽  
Scythian Period ◽  
Very High

В статье рассмотрены палеоантропологические материалы грунтовых захоронений середины I тыс. до н. э., расположенных на территории Верхнего Дона. Находки получены в результате раскопок многослойного памятника Ксизово-19. Работы проводились Раннеславянской археологической экспедицией ИА РАН под руководством А. М. Обломского. Исследование антропологических коллекций проводилось по комплексной биоархеологической программе и позволило осветить ряд вопросов об образе жизни населения этой эпохи. Были проанализированы показатели уровня стрессов и физических нагрузок в рассматриваемой группе. Следует обратить внимание на очень высокий процент присутствия зубных патологий. При сравнении серий из грунтовых погребений и подкурганных захоронений выявлены различия в состоянии зубочелюстной системы и присутствие патологических состояний, фиксируемых на зубах в большей степени в группе из курганов. The paper provides an overview of paleoanthropological remnants from ground burials dating back to the mid I mill. BC located in the Upper Don region. The finds were obtained during excavations of the Ksizovo-19 multi-layer site. The excavations were carried out by the Early Slavic Expedition of the Institute of Archaeology, RAS, led by A. M. Oblomskiy. The study of the anthropological assemblages was performed according to a comprehensive bioarchaeological program. This makes it possible to cover a number of issues regarding the life style of the population at that time. The stress level and physical activity in the studied group were analyzed. A very high percentage of dental pathologies should be noted. Comparison of series from the ground burials and the kurgans burials revealed differences in the conditions of the dentofacial systems and presence of a greater number of pathological conditions of the teeth in the kurgan series.

scholarly journals – The impact of the requirements of the business continuity in the Sustainability performance of the company relying strategy of risk management– A case Study in Al- Fayha / Basra branch Ready Construction Co limited: تأثير متطلبات استمرارية الأعمال في الأداء المستدام للمنظمة باعتماد استراتيجية إدارة المخاطر– دراسة حالة في شركة الفيحاء لصناعة البناء الجاهز المحدودة / البصرة –

2019 ◽  
Vol 3 (6) ◽  
Author(s):  
Iman Askar Hawi
Keyword(s):  
Risk Management ◽  
Quantitative Methods ◽  
Business Continuity ◽  
Sustainability Performance ◽  
Strategic Role ◽  
Interactive Relationship ◽  
Main Components ◽  
The Impact

  Purpose: This study is intended to improve the Sustainability performance in the Al- Fayha / Basra branch Ready Construction Co limited relationship between the strategy of risk management and requirements of the business continuity and investigation of the findings. Methodology: Making up a conceptual model of the business continuity tracks flow in the Al- Fayha / Basra branch Ready Construction Co limited The model is based on the interactive relationship between the risk management and requirements of the business continuity of Some help was available quantitative methods, relying on a combination of descriptive and quantitative approaches, in order for the accuracy of the results. results: the Al- Fayha / Basra branch Ready Construction Co limited been the subject matter of the research. It lacks the conceptual pattern that systemizes , integrates and directs its main components towards a comprehensive improvement of the company. In addition it requires relative interest in the strategic role of the strategy of risk management and its dual effects on both the business continuity and the Sustainability performance of the Company. The main recommendations were to identify the risks that affect the business continuity of the company, to control them in order to achieve full response to all business continuity requirements.    

scholarly journals IMPLEMENTASI PENDIDIKAN LIFESKILL SEJAK DINI DALAM PEMBELAJARAN ENTERPRENEURSHIP

2018 ◽  
Vol 4 (1) ◽  
pp. 85
Author(s):  
Yeni Suprihatin ◽  
Etika Lisyana Dewi
Keyword(s):  
Qualitative Research ◽  
Everyday Life ◽  
Learning Activities ◽  
Life Skill ◽  
Report Result ◽  
Depth Interview ◽  
Main Components ◽  
Study Type ◽  
And Training

Life skill education is an education that provides basic supplies and training to learners about the values of life needed and useful for the development of everyday life. Research on integrated life skill education in enterpreneurship subject in SMP Cahaya Bangsa School aims to know what life skill orientation in Entrepreneurship subject and examine the extent of life skill education implementation in Enterpreneurship subject. The design of this study used qualitative research with case study type. A descriptive inductive approach is used to describe a case by understanding symptoms and meaning. Researchers use in-depth interview techniques, digging information with direct observation, and study documentation. In analyzing the data, the researcher through three main components, namely, data reduction, display data, and data conclusion drawing. The results showed that the concept of life skill education is internalized in the entrepreneurship subject syllabus, then the teacher describes it in various learning activities such as washing activities, ironing activities, live in program, and market day. Evaluation done by teacher in assessing ability of life skill of student is by observing directly activity in enterpreneurship subject and student also given duty to write report result of activity live in.

scholarly journals Borehole Rehabilitation: A Case Study in the Dunkwa Mining Town

2020 ◽  
Vol 20 (2) ◽  
pp. 11-17
Author(s):  
A. Ewusi ◽  
J. Seidu
Keyword(s):  
Water Supply ◽  
Central Region ◽  
Pumping Test ◽  
Implementation Cost ◽  
Mining Town ◽  
Long Time ◽  
Borehole Camera ◽  
The Cost ◽  
Very High

Rehabilitation works were carried out on boreholes in the Dunkwa Mining town in the Central Region of Ghana. These works were carried out because the boreholes had lost their original yields due to clogging, corrosion and encrustation and had been abandoned for a long time. The cost of drilling a new well and assessing the productivity of the well is $4,500 which is more expensive that carrying out rehabilitation works which is cheaper, about $800. Also, the initial yields of the boreholes were very high according to the feasibility report which is not a common characteristic of the rocks in the area. Camera inspection followed by rehabilitation, pre and post pumping tests were carried out to assess whether there has been an improvement in their yield after the exercise and that the yield obtained will be adequate for a water supply design. Results show that all the boreholes had an improvement in their yields (57.19 - 259.80 %) after the rehabilitation. It can therefore be concluded that rehabilitation is effective in restoring boreholes to their original yields. Organisations drilling boreholes to communities can take advantage of rehabilitation of the existing boreholes located in the communities which are high yielding, thereby reducing project implementation cost. Keywords: Borehole Rehabilitation, Borehole Yields, Borehole Camera Inspection, Pumping Test

scholarly journals Practical Considerations for Implementing Species Distribution Essential Biodiversity Variables

2021 ◽  
Vol 5 ◽  
Author(s):  
Robin Boyd ◽  
Nick Isaac ◽  
Robert Cooke ◽  
Francesca Mancini ◽  
Tom August ◽  
...  
Keyword(s):  
Species Distribution ◽  
Biodiversity Indicators ◽  
The United Kingdom ◽  
Occupancy Detection ◽  
Essential Biodiversity Variables ◽  
The Uk ◽  
Species Occupancy ◽  
Very High ◽  
The Ideal

Species Distribution Essential Biodiversity Variables (SD EBVs; Pereira et al. 2013, Kissling et al. 2017, Jetz et al. 2019) are defined as measurements or estimates of species’ occupancy along the axes of space, time and taxonomy. In the “ideal” case, additional stipulations have been proposed: occupancy should be characterized contiguously along each axis at grain sizes relevant to policy and process (i.e., fine scale); and the SD EBV should be global in extent, or at least span the entirety of the focal taxa’s geographical range (Jetz et al. 2019). These stipulations set the bar very high and, unsurprisingly, most operational SD EBVs fall short of these ideal criteria. In this presentation, I will discuss the major challenges associated with developing the idealized SD EBV. I will demonstrate these challenges using an operational SD EBV spanning ~6000 species in the United Kingdom (UK) over the period 1970 to 2019 as a case study (Outhwaite et al. 2019). In short, this data product comprises annual estimates of occupancy for each species in all sampled 1 km cells across the UK; these are derived from opportunistically-collected species occurrence data using occupancy-detection models (Kéry et al. 2010). Having discussed which of the “ideal” criteria the case study satisfies, I will then touch on what are, in my view, two underappreciated challenges when constructing SD EBVs: dealing with sampling biases in the underlying data and the difficulty in evaluating the extent to which they bias the final product. These challenges should be addressed as a matter of urgency, as SD EBVs are increasingly applied in important settings such as underpinning national and international biodiversity indicators (see e.g., https://geobon.org/ebvs/indicators/).

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