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Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1666
Author(s):  
Dirk van Vuuren ◽  
Annlizé Marnewick ◽  
Jan Pretorius

Fundamental mathematical principles were applied to calculate the return on investment (ROI) of a multiple inclination, rooftop-mounted, photovoltaic (PV) system that is connected to a structured tariff network. Recent history has seen a disproportionate increase in electricity tariffs within South Africa, enabling an increase in the deployment rates of PV technologies. Given the inherent uncertainty associated with simulating the electricity yield of a PV system, it can become difficult to estimate the ROI in advance. This study contributes to existing knowledge by presenting a process for calculating the ROI of a case study rooftop-mounted PV system using mathematical first principles where structured tariffs apply. The PV modules were mounted to a curved roof structure, ranging from 9° towards a southerly direction to 10° towards a northerly direction. The research results indicate that since the PV system is located within the southern hemisphere, the ROI will increase when PV modules are orientated towards the northerly direction to attain a maximum of R0.0059/Wp/Day at 10°, and a minimum of R0.0025/Wp/Day at 9° towards the southerly direction in the winter season. Summer maximum ROI yielded an average of between R0.0050/Wp/Day and R0.0052/Wp/Day, irrespective of the angle of inclination of the PV modules. It was concluded that PV systems must be designed to favour winter electricity production for increased ROI where structured tariffs apply within a South African context.


Author(s):  
Timothy J Lysyk ◽  
Shaun J Dergousoff ◽  
Kateryn Rochon ◽  
Neil B Chilton ◽  
Anne M Smith

Abstract The geographic distribution of the Rocky Mountain wood tick, Dermacentor andersoni Stiles, was determined in Alberta, Canada, by drag sampling at 86 and 89 sites during 2011 and 2012, respectively. Tick density and prevalence varied between years, averaging (range) 1.0 (0–26.2) and 5.9 (0–110) ticks/1,000 m2 in 2011 and 2012, respectively. Ticks were detected at 24.4% and 42.7% of the sites sampled in each respective year. Tick density and presence declined in a northerly direction to 51.6°N and in a westerly direction to ca. 113°W, except for a small area of high density at the edge of the Rocky Mountains in the southeastern portion of the province. Ticks were most abundant in the Dry Mixedgrass and Montane natural subregions and in areas with Brown Chernozemic, Regosol, and Solodized Solonetzic great soil groups. A logistic regression model indicated that tick presence was increased in the Dry Mixedgrass natural subregion and in regions with greater temperatures during the previous summer and normal winter precipitation but was reduced in areas with Dark Brown Chernozemic soils. The model will be useful for predicting tick presence and the associated risk of tick-borne diseases in the province.


2020 ◽  
Author(s):  
Krzysztof Piksa ◽  
Wojciech J. Gubała

Abstract Schreiber’s bent-winged bat Miniopterus schreibersii is a typical Mediterranean species. To date, the northern limit of its distribution range ran along the northern ends of Slovakia. This paper describes the first record of this species in Poland, at a more northerly site for this part of Europe. On October 7, 2015, an adult female of M. schreibersii was caught in the underground part of the New Castle in Rożnów, southern Poland (49° 46′ 23.8″ N, 20° 41′ 43.1″ E; 339 m a.s.l.). Subsequent observations were made at the same site during the autumn of 2018 and 2019. The likely migration route and the causes for a widening of the species distribution range are discussed in this paper. Observations suggest that, like other Mediterranean species, it has expanded its range in northerly direction.


Author(s):  
Derek Fraser

The book is a comprehensive and definitive history of the Leeds Jewish community, which was – and remains – the third largest in Britain. It is organised in three parts: Context (history, urban, demography); Chronology (covering the period from the mid-nineteenth century to the 1940s); and Contours (analysing themes and aspects of the history up to the present time). The book shows how a small community was affected by mass immigration, and through economic progress and social mobility achieved integration into the host society. It is a story of entrepreneurial success which transformed a proletarian community into a middle-class society. Its members contributed extensively to the economic, social, political and cultural life of Leeds, which provided a supportive environment for Jews to pursue their religion, generally free from persecution. The Leeds Jewish community lived predominantly in three locations which changed over time as they moved in a northerly direction to suburbia.


2017 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
S K M Bhasha ◽  
P Siva Kumar Reddy

The Veligonda range which separates the Nellore district from Kadapa and Kurnool is the back bone of the Eastern Ghats, starting from Nagari promontory in Chittoor district. It runs in a northerly direction along the western boarders of the Nellore district, raising elevation of 3,626 feet at Penchalakona in Rapur thaluk. Veligonda hill ranges have high alttudinal and deep valley. These hills have rich biodiversity and many rare, endangered, endemic and threatned plants are habituated in these hills. The present paper mainly deals with the ethanobotanical plants used by local people.


Author(s):  
Володимир Миколайович Федоров

The article considers three-stage pendulum gyrocompass ground with torsion suspension unmanaged sensor, equipped with high-precision digital angle sensor azimuthal position sensor and information processing unit. During processing of information isused an indirect method to get facts about initial deviations of dynamical systems.In the process of improving the instrument have revealed that a further increasing of accuracy due to the necessity to consider the following factors. During the measurement around the vertical axis of the sensor operates permanent uncontrolled moment due to operational reasons are different from measurement to measurement. Specified point shifts the center of oscillation of the azimuthal sensor, which is in accordance with the procedure identified azimuth northerly direction on a constant value. For self-compensation of this error have been proposed several methods based on measurements with different but fixed parameters of the device. However, these measures have extended more than twice the measurement process.In this article there is proposing to define the position of the geographic meridian based on the analysis of the azimuthal motion sensor gyro during acceleration of its rotor. The proposal can bring dual gain in reducing measurement time: at first, the rotor becomes "staff " rather than ballast gyro operation mode, as it was before; secondly, there is no need for special measures to combat harmful vertical moments, as the shift of the equilibrium caused by the action of the latter, is variable in time, which allows to determine the magnitude of harmful moment during a single measurement.


Geophysics ◽  
2014 ◽  
Vol 79 (2) ◽  
pp. B37-B50 ◽  
Author(s):  
P. Bergmann ◽  
M. Ivandic ◽  
B. Norden ◽  
C. Rücker ◽  
D. Kiessling ◽  
...  

A combination of seismic and geoelectric processing was studied by means of a structurally constrained inversion approach. Structural constraints were interpreted from the seismic data and integrated into the geoelectric inversion through a local regularization, which allowed inverted resistivities to behave discontinuously across defined boundaries. This arranged seismic processing and constrained resistivity inversion in a sequential workflow, making the generic assumption that the petrophysical parameters of both methods change across common lithostructural boundaries. We evaluated the approach using a numerical example and a real data example from the Ketzin [Formula: see text] pilot storage site, Germany. The latter demonstrated the efficiency of this approach for combining 4D seismic and surface-downhole geoelectric data. In consistence with the synthetic example, the constrained resistivity inversions produced clearer delineated images along the boundary between caprock and reservoir formation. Near the [Formula: see text]-flooded reservoir, the seismic and geoelectric time-lapse anomalies correlated well. At some distance to the downhole electrodes, however, the geoelectric images conveyed a notably lower resolution in comparison to the corresponding seismic images. Both methods confirm a northwesterly trend for the [Formula: see text] migration at the Ketzin site, although a rather northerly direction was initially expected. The results demonstrate the relevance of the presented approach for the combination of both methods for integrated geophysical [Formula: see text] storage monitoring.


1997 ◽  
Vol 87 (3) ◽  
pp. 745-754
Author(s):  
Xiaohua Peng ◽  
Eugene D. Humphreys

Abstract Receiver functions are derived from teleseismic waves recorded during the 1988 to 1989 PASSCAL Basin and Range passive-source seismic experiment in northwestern Nevada. A velocity model involving both a planar dipping Moho and crustal anisotropy is needed to explain the radial and tangential motions of the observed PS conversions. An arrival-time difference often observed between radial and tangential Moho PS conversions suggests an anisotropic crust. The PS conversions are large and indicate a major discontinuity under the area. The particle motion directions for most of the tangential components change sign between South American events and events from the other two source areas (Japan and Tonga regions), providing good evidence for a Moho dipping approximately to the north. Also, the PS conversions from the Moho follow direct P arrivals by about 3.2 sec under the southern part of the array, 3.4 sec under the southern central part of the array, and 3.7 sec under the northern part of the array, indicating a Moho that varies in depth from about 26 to 31 km. A velocity model with the Moho dipping ∼9° in a nearly northerly direction and an anisotropic crust with a split time of ∼0.25 sec and a fast axis of ∼130° best explain these observations.


Koedoe ◽  
1996 ◽  
Vol 39 (2) ◽  
Author(s):  
Francine Rubin ◽  
A.R. Palmer

The major plant communities of the Karoo National Park are described using the methods of the Zurich-Montpellier school of phytosociology, to assist with the formulation of a management strategy for the park. The vegetation physiognomy consists of Montane Karoo grassy shrublands. Karoo grassy dwarf shrublands. Karoo succulent dwarf shrublands and riparian thicket. Steep elevation and precipitation gradients within the study area have a direct impact on gradients in the vegetation. High elevation (1 800 m), and relatively high rainfall (406 mm) montane grasslands occupy communities dominated by grasses (Merxmuellera disticha, Themeda triandra) and woody species (Diospyros austro-africana, Elytropappus rhinocerotis, Euryops annae, Passerina montana). The increasing aridity away from the escarpment edge in a northerly direction is steep, and Montane Karoo dwarf shrublands replace these mesic communities. Species such as Eriocephalus ericoides, Rosenia oppositifolia and Pteronia tricephala dominate. At lower elevation (800 m) the precipitation is very low (175 mm) and uncertain (coefficient of variation of 78 ). The substrata influence the vegetation, with the sandy substrata of the drainage lines supporting more woody taxa (Acacia karroo, Lycium cinereum) and grasses (Hyparrhenia hirta, Stipagrostis namaquensis, Cenchrus ciliaris). Moving away from the mesic environment of the riparian zone, rapid desiccation occurs and the most xeric communities are encountered, dominated by Stipagrostis obtusa, S. ciliata and Pent-da incana. This document provides descriptions of the general communities and their associated landscape, lithology and soils.


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