Wide Range Of Altitudes Research Articles

Numerical Simulation on Optimization of Pintle Base Shape in Planar Expansion-Deflection Nozzles

Altitude compensating nozzles provide optimum performance over a wide range of altitudes. The planar expansion–deflection nozzle is one such nozzle. It has a rectangular cross-section, and altitude compensation is achieved by incorporating a pintle beyond the throat of a conventional convergent–divergent nozzle. The objective of the present Paper is to investigate the variations in flow caused as a result of a varying pintle base shape in a planar expansion–deflection nozzle. The computational fluid dynamics approach is used for conducting the analysis. Nozzle contour and pintle geometry up to the throat is kept unchanged, and simulations are conducted by altering the geometry of the pintle base profile. For each expansion–deflection nozzle configuration, the flow pattern, base pressure, and coefficient of thrust generated by nozzle are studied over a range of nozzle pressure ratios. The results of the numerical study reveal that the curved pintle with highest base curvature showed better overall performance in terms of contribution of base pressure to thrust output, whereas the pintle with an inclined base indicated the better overall coefficient of thrust when compared to pintles at higher nozzle pressure ratios due to higher contribution from momentum thrust.

MAPPING SYSTEM AND PHOTOGRAMMETRIC PROCESSING METHOD FOR TETHERED BALLOON PLATFORM

Abstract. As a platform with the advantages of safety, wide altitude range and long flight time, tethered balloon has been used in archaeology, coastal, island mapping and other related fields. Tethered balloon is tied to the mooring system by tether rope, and often moves in a small range with the airflow, resulting in a very close distance between the camera stations. Due to the small base-to-height ratio, failure of relative orientation or poor quality of point cloud tend to appear frequently. In this paper, a mapping system for tethered balloon is introduced which consists of a wide-angle camera, two auxiliary orientation cameras, and a dual GNSS/IMU system. The wide-angle camera combined by five cameras provides a larger observation range. Two auxiliary orientation cameras installed at the end of extension rods are designed to increase the baseline. The system should be operated during the taking-off, hovering and landing stages of the tethered balloon, so as to take images of different altitudes. The system has been adopted in the first experimental flight in 2018 to perform island topographic survey. Data processing method was applied to test the effect of the system. The method that choosing wide-angle images of different heights, and auxiliary images at low-altitude can be used for aerial triangulation successfully, and obtain point cloud with good quality. The results showed that by adding auxiliary cameras and taking images of different heights for data processing, the problem of small intersection angle could be overcome to some extent.

Review: Floral resources diversity and vegetation types important for honeybees in Ethiopia

Abstract. Addi A, Bareke T. 2019. Review: Floral resources diversity and vegetation types important for honeybees in Ethiopia. Asian J For 3: 64-68. The high biodiversity of Ethiopia is attributed to its wide range of altitude and great geo-morphological diversity. This has resulted in the existence of a high diversity of floral resources of which majority of them are visited by honeybees. This paper aimed to review existing studies on bee floral resources in Ethiopia to understand the types of bee plants, floral diversity, flowering period and food source offered by the plants. Over 1500 species of indigenous and exotic plants belonging to 105 bee plant families have been identified. The growth form of bee forage comprises 41.6% herb, 28.7% shrubs, 21.7% trees, and 8% climbers. The majority of bee plant species flower from September to November and April to May, resulting in two major honey flow periods in the country. From this information, Ethiopia has rich bee forage diversity across different vegetation types, however, further collection and documentation of bee flora are required in unaddressed areas of the country. Thus in situ conservation by ecological restoration, and raising and planting of seedlings of bee forages should be promoted for sustainable honey production.

Long‐duration fully autonomous operation of rotorcraft unmanned aerial systems for remote‐sensing data acquisition

AbstractRecent applications of unmanned aerial systems (UAS) to precision agriculture have shown increased ease and efficiency in data collection at precise remote locations. However, further enhancement of the field requires operation over long periods of time, for example, days or weeks. This has so far been impractical due to the limited flight times of such platforms and the requirement of humans in the loop for operation. To overcome these limitations, we propose a fully autonomous rotorcraft UAS that is capable of performing repeated flights for long‐term observation missions without any human intervention. We address two key technologies that are critical for such a system: full platform autonomy to enable mission execution independently from human operators and the ability of vision‐based precision landing on a recharging station for automated energy replenishment. High‐level autonomous decision making is implemented as a hierarchy of master and slave state machines. Vision‐based precision landing is enabled by estimating the landing pad's pose using a bundle of AprilTag fiducials configured for detection from a wide range of altitudes. We provide an extensive evaluation of the landing pad pose estimation accuracy as a function of the bundle's geometry. The functionality of the complete system is demonstrated through two indoor experiments with duration of 11 and 10.6 hr, and one outdoor experiment with a duration of 4 hr. The UAS executed 16, 48, and 22 flights, respectively, during these experiments. In the outdoor experiment, the ratio between flying to collect data and charging was 1–10, which is similar to past work in this domain. All flights were fully autonomous with no human in the loop. To our best knowledge, this is the first research publication about the long‐term outdoor operation of a quadrotor system with no human interaction.

Genomic analysis reveals variant association with high altitude adaptation in native chickens

Native chickens are endangered genetic resources that are kept by farmers for different purposes. Native chickens distributed in a wide range of altitudes, have developed adaptive mechanisms to deal with hypoxia. For the first time, we report variants associated with high-altitude adaptation in Iranian native chickens by whole genome sequencing of lowland and highland chickens. We found that these adaptive variants are involved in DNA repair, organs development, immune response and histone binding. Amazingly, signature selection analysis demonstrated that differential variants are adaptive in response to hypoxia and are not due to other evolutionary pressures. Cellular component analysis of variants showed that mitochondrion is the most important organelle for hypoxia adaptation. A total of 50 variants was detected in mtDNA for highland and lowland chickens. High-altitude associated with variant discovery highlighted the importance of COX3, a gene involved in cell respiration, in hypoxia adaptation. The results of study suggest that MIR6644-2 is involved in hypoxia and high-altitude adaptations by regulation of embryo development. Finally, 3877 novel SNVs including the mtDNA ones, were submitted to EBI (PRJEB24944). Whole-genome sequencing and variant discovery of native chickens provided novel insights about adaptation mechanisms and highlights the importance of valuable genomic variants in chickens.

Distribution of a New Invasive Species, Sipha maydis (Heteroptera: Aphididae), on Cereals and Wild Grasses in the Southern Plains and Rocky Mountain States.

Sipha maydis Passerini (Heteroptera: Aphididae) is a cereal pest with an extensive geographical range that includes countries in Europe, Asia, Africa, and South America. Reports of S. maydis in the United States have been infrequent since it was first detected in California, 2007. Two studies, focused (NW CO) and multistate (OK, TX, NM, CO, UT, WY), were conducted to determine the distribution and host range of S. maydis in the Rocky Mountain and Southern Plains states over a 3-yr period, 2015-2017. In 2015, focused sampling in NW Colorado found S. maydis at 59% of the 37 sites, primarily on wheat. Sipha maydis did not survive extreme winter temperatures from late December 2015 to early January 2016 that ranged from -9.0 to -20.9°C over a 9-d period, which resulted in no aphids detected in 2016. In the multistate study, S. maydis occurred in 14.6% of 96 sites sampled in 2015, 8% of 123 sites in 2016, and 9% of 85 sites in 2017 at wide range of altitudes from 1,359 to 2,645 m. Sipha maydis occurred mainly in NW and SW Colorado and NE New Mexico along with a few sites in NE Colorado, SE Utah, and SE Wyoming. This aphid mainly infested wheat followed by a variety of eight wild grass species. No parasites, predators, sexual morphs, or significant plant damage occurred at the sites. Sipha maydis utilized 14 hosts in the United States including 8 new host records, which expands its host range to 52 plant species worldwide. Sipha maydis may be of concern to wheat, barley, and sorghum production in the United States if its populations continue to increase.

Genetic structure of Pinus parviflora on Mt. Fuji in relation to the hoarding behavior of the Japanese nutcracker

AbstractPinus parviflora (Japanese white pine) is distributed along a wide range of altitudes between 1100 and 2500 m above sea level (asl) on the northwestern slope of Mt. Fuji in Japan. The seeds of P. parviflora are presumed to be dispersed from the mountainous area to the timberline by the Japanese nutcracker (Nucifraga caryocatactes var. japonica). We aimed to clarify the effect of the nutcracker on the genetic diversity and structures of P. parviflora populations on Mt. Fuji. Leaf samples were collected from eight populations at altitudes between 1100 and 2500 m asl. Using 11 microsatellite markers, we investigated the genetic diversity and structures of P. parviflora populations on Mt. Fuji. The average expected heterozygosity (HE), allelic richness (Ar), and inbreeding coefficients (FIS) of the P. parviflora populations on Mt. Fuji were 0.66, 1.66, and 0.14, respectively, suggesting a lower genetic diversity in comparison with those of P. parviflora populations in other regions of Japan. The genetic structure of the population at the lowest altitude of 1100 m was significantly different from that of the other populations. However, certain individuals in the populations at higher altitudes (2300–2500 m asl) were likely derived from populations at lower altitudes (1100–1500 m asl), probably because of the hoarding behavior of the nutcracker. Our results indicate that seeds carried from low altitudes by nutcrackers have become established at the timberline and have contributed to expanding the distribution and maintaining the genetic diversity of P. parviflora on Mt. Fuji.

Observed and Simulated Teleconnections Between the Stratospheric Quasi‐Biennial Oscillation and Northern Hemisphere Winter Atmospheric Circulation

AbstractThe Quasi‐Biennial Oscillation (QBO) is the dominant mode of interannual variability in the tropical stratosphere, with easterly and westerly zonal wind regimes alternating over a period of about 28 months. It appears to influence the Northern Hemisphere winter stratospheric polar vortex and atmospheric circulation near the Earth's surface. However, the short observational record makes unequivocal identification of these surface connections challenging. To overcome this, we use a multicentury control simulation of a climate model with a realistic, spontaneously generated QBO to examine teleconnections with extratropical winter surface pressure patterns. Using a 30‐hPa index of the QBO, we demonstrate that the observed teleconnection with the Arctic Oscillation (AO) is likely to be real, and a teleconnection with the North Atlantic Oscillation (NAO) is probable, but not certain. Simulated QBO‐AO teleconnections are robust, but appear weaker than in observations. Despite this, inconsistency with the observational record cannot be formally demonstrated. To assess the robustness of our results, we use an alternative measure of the QBO, which selects QBO phases with westerly or easterly winds extending over a wider range of altitudes than phases selected by the single‐level index. We find increased strength and significance for both the AO and NAO responses, and better reproduction of the observed surface teleconnection patterns. Further, this QBO metric reveals that the simulated AO response is indeed likely to be weaker than observed. We conclude that the QBO can potentially provide another source of skill for Northern Hemisphere winter prediction, if its surface teleconnections can be accurately simulated.

ExoMars Atmospheric Mars Entry and Landing Investigations and Analysis (AMELIA)

The entry, descent and landing of Schiaparelli, the ExoMars Entry, descent and landing Demonstrator Module (EDM), offered a rare (once-per-mission) opportunity for in situ investigations of the martian environment over a wide altitude range. The aim of the ExoMars AMELIA experiment was to exploit the Entry, Descent and Landing System (EDLS) engineering measurements for scientific investigations of Mars’ atmosphere and surface. Here we present the simulations, modelling and the planned investigations prior to the Entry, Descent and Landing (EDL) event that took place on 19th October 2016. Despite the unfortunate conclusion of the Schiaparelli mission, flight data recorded during the entry and the descent until the loss of signal, have been recovered. These flight data, although limited and affected by transmission interruptions and malfunctions, are essential for investigating the anomaly and validating the EDL operation, but can also contribute towards the partial achievement of AMELIA science objectives.

Species distribution of genus Salacca

Salak is native plant from tropics that is grouped in genus Salacca. Species number of this genus based on valid name is 23 species. The spread of salak species in the world has never been published full in one paper. Several publication often informed only one species of salak but the others informed more. Therefore this paper aims to present the distribution salak species in the world. All of specimen salak were observed from Herbarium Bogoriense, Bogor; Herbarium Leiden, Netherlands; Herbarium Kewense, England. The specimens observed amounted to 515 sheets. Result showed the distribution of salak species is concentrated in three regions namely Borneo, Malay Peninsular, and Sumatra. Borneo island is highest diversity of salak because there were found 11 salak species, that indicated as centre of salak diversity and centre of salak origin in the world. Most of the species from this genus are restricted to very small areas. The salak habitat varied with wide range of altitudes, from 5 m fsl to 1700 m fsl, but most of them are in the lowlands. The species with the widest range of altitudes are S. dolicholepis but S. wallichiana and S. zalacca were most found in several regions. There is relationship between salak species and distribution areas statistically.

Assessment of spatial distribution of enset plant diversity and enset bacteria wilt using geostatistical techniques in Yem special district, Southern Ethiopia

BackgroundEnsete plant (Enset ventricosum) is a monocarpic perennial crop, found under genus Ensete. It is mainly known and planted by farmers as a drought resistant crop and staple food in the rural community of southern Ethiopia. Large numbers of enset clones are growing in a wide range of altitude. Currently, enset plant diversity and production has been endangered by devastated enset bacterial wilt disease (EBW) which is caused by Xanthomonas campestris pv. musacearum. The study aimed at to assess the spatial distribution of enset clone richness and diversity, and enset bacterial wilt disease in Yem special district of southern Ethiopia using ArcGIS geostatistical (Kriging) techniques.ResultsThe highest diversity was recorded in Semu Awash kebele with Shannon index of 3.38 and the lowest was in Nuba kebele an index of 2.56. The Sorenson similarity/variation indices showed that Gurmina Hangeri/Meleka and Ediya/Gurmina Hangeri each pairs of kebeles share 18 clones with index value of 0.81 and 0.67, respectively. While lowest share recorded between Laignaw (upper) Kesheli and Tachignaw (lower) Kesheli kebeles with Sorenson indices of 0.16 (only five clones in common recorded). Enset bacterial wilt disease is distributed in all sampled kebeles in varying ranges. The rate of disease prevalence, incidence and severity lies between ranges of 75–100%, 46.8–88.9%, and 36.1–81.4%, respectively. Semu Awasho and Laignaw Kesheli kebeles scored 100% prevalence while in Shemona Metelo kebele it is scored 75%.ConclusionsTherefore, the analyzed results indicate that it is necessary to compact EBW distribution and to conserve enset richness and diversity in the district for the sake of enhancing food security of farmers at household level in Yem special district. Otherwise, in the longer run the food security and enset plant species would be endanger and it may have significant impact on socio-economic development of the rural community. This study considered limited bio-physical factors for EBW analysis, we recommend in further research in the future should be conducted including other socio-biophysical factors.

EMEC instability based on kappa-Maxwellian distributed trapped electrons in auroral plasma

In space plasmas, particle distributions are often observed having high energy tails and are well fitted by kappa distribution function. However, in auroral region electrons are expected to be accelerated mainly along the magnetic field lines and one may expect Maxwellian behaviour in perpendicular direction. Therefore, in the present study propagation characteristics of electromagnetic electron cyclotron (EMEC) waves is studied by employing kappa-Maxwellian distribution function for energetic trapped electrons in auroral region. Real frequency and the growth rate expressions have been solved numerically for kappa-Maxwellian plasma and then analyzed by considering the effect of different plasma parameters for wide range of auroral altitudes. The numerical results obtained show that growth rate increases with the increase in ratio \({\omega_{pe}} / {\varOmega_{e}}\), plasma beta, temperature anisotropy \({T_{\bot}} / {T_{\parallel}}\) and trapped electron drift speed but decreases when superthermal electron population increases.

<b>An annotated checklist of the birds of upper Chenab catchment, Jammu & Kashmir, India</b>

Watershed avifaunal inventories are useful in devising management strategies appropriate to the habitat, as well as species conservation. The Chenab River basin forms one of the largest and most important river basins in Jammu & Kashmir. The upper Chenab catchment offers a rich and diverse fauna, especially birds, owing to variety of habitats, different climatic regimes, and a wide range of altitude,. We present an avifaunal list of four watersheds—Bhot, Marusudar, Kalnai and Neeru of the Chenab River basin including Kishtwar Town and the surrounding area of the upper Chenab catchment over an elevation range of 820–4,500 m. The list includes 251 species belonging to 60 families and 150 genera of which six are globally threatened, 127 residents, 124 migrants and three new to the state. The paper also describes species-wise habitat occupancy, feeding behaviour, migratory status and abundance of the avifauna. The study reveals that mosaic habitats comprising forests, riverbeds, rangelands and rocky outcrops are crucial for the conservation of birds in the region.

Reconstruction of altitudinal transportation range of leaves based on stomatal evidence: An example of the Early Pleistocene Fagus leaf fossils from central Japan

Fossil plant assemblages play a critical role in paleoenvironment estimation, especially for the Cenozoic. However, the extent that the fossil assemblage reflects the source forest is difficult to estimate. The comparison between modern assemblages and their subfossil assemblages shows a significant difference, indicating that the transportation of plant organs can affect the accuracy of paleoenvironment analysis. In this study, we aim to detect leaf transport based on stomatal frequency (stomatal index and stomatal density) variation of 30 fossilized Fagus crenata leaves from the Sayama Formation (1.54–1.66 Ma). We distinguished the sun and shade morphotype of fossil leaves by using undulation index and calculated stomatal frequency variation of only sun fossil leaves. Considering the stomatal index variation of fossil Fagus crenata leaves, the paleo-pCO2 variation in a warm period between 1.54 Ma and 1.66 Ma was estimated as ca. 35.0 to 39.6 pa. Based on this paleo-pCO2 variation, altitudinal transportation range of the Early Pleistocene fossil Fagus crenata leaves was estimated at over 1000 m. We presume that leaves of Fagus crenata in the fossil assemblage possibly had come from a wide range of altitudes near the fossil site during the Early Pleistocene. This provides an example of altitudinal transportation of plants before their deposition, which suggests a consideration when reconstructing the palaeovegetation and palaeoclimate from fossil assemblages.

Spectral Study of Ellerman Bombs. Photosphere

The results of analysis of spectral observations of two Ellerman bombs (EB-1 and EB-2), which were formed and have evolved in the area of emerging magnetic flux in active region (AR) NOAA 11024, are presented. Spectral data with high spatial and temporal (approximately 3 s) resolution were obtained using the THEMIS French–Italian solar telescope on July 4, 2009. The observation duration was 20 min. The spectral region of λ ≈ 630 nm with photospheric lines forming in a wide altitude range (neutral iron lines Fe I λ 630.15, 630.25, and 630.35 nm and titanium line Ti I λ 630.38 nm) was examined. The brightness of EB-1 decreased in the process of observations, while the brightness of EB-2 increased. The profiles of metal lines determined at different stages of EBs evolution were asymmetric. This asymmetry was more pronounced in lines that had formed in the lower photospheric layers and often had profiles with several components. The half-width of profiles increased with a reduction in their central depth. The variation of central intensities of Fraunhofer lines in the spectra of EBs and their vicinity at different stages of EB evolution was analyzed. The EBs formed in intergranular lanes. An increase in the core intensity of all the studied photospheric lines was correlated spatially with an increase in the wings intensity of the Hα line. Brightness variations at all photospheric levels were of an oscillatory nature with an interval of 1–5 min. The observed temporal variations of Fraunhofer line intensities in the spectra of the studied AR section suggest that the emergence of the new magnetic flux induced consecutive magnetic reconnections in the EB-1 region, the excitation propagated along a magnetic loop and initiated the formation of EB-2, and the two bombs then evolved as a physically connected pair.

Distribution of non-native brook trout (Salvelinus fontinalis) across Norwegian waterbodies – is it an invasive species?

Non-native brook trout (Salvelinus fontinalis MITCHILL, 1815) was introduced into Norway in 1883. However, it was not until the late 1970s that this acid-tolerant salmonid species was stocked into many acidified lakes that many populations became established. In 2004, all brook trout stocking in Norway ceased. In this study, we surveyed the distribution of brook trout in Norwegian water bodies. A totally of 202 self-sustaining populations were identified, mostly in unregulated lakes (n=101), streams (n=71) and also to some extent in reservoirs (n=25). Only four populations were found in inland rivers, and one population in a river with Atlantic salmon (Salmo salar L.). Localities with brook trout covered a wide range of altitudes and sizes. Analyses of time-series catches in sympatric populations of brown trout (Salmo trutta L.) and brook trout from 12 lakes (1997-2012) revealed a strong decline in brook trout stocks. A similar development in abundance has also emerged from other studies in recent years. Generally, lake-dwelling brook trout is regarded as a low-risk species with respect to invasiveness. However, brook trout/brown trout interactions may be habitat-specific, as brook trout may dominate in small and relatively cold streams.

Plasma Effects in Dust Devils near the Martian Surface

Plasma−dust effects in the martian atmosphere are discussed. A specific feature of the martian atmosphere is the presence of dust grains in a wide range of altitudes. Taking into account the presence of the martian ionosphere and the high conductivity of the medium at lower altitudes, the appearance of plasma systems in the martian atmosphere can be considered quite a common phenomenon. Special attention is paid to dust devils that frequently form in the martian atmosphere and can efficiently lift dust grains. The processes of dust grain charging as a result of triboelectric effect and generation of electric fields in a dust devil are discussed. The dynamics of dust grains in such a vortex is simulated with allowance for their charging and the generated electric field.

Computational study of performance characteristics for truncated conical aerospike nozzles

Aerospike nozzles are advanced rocket nozzles that can maintain its aerodynamic efficiency over a wide range of altitudes. It belongs to class of altitude compensating nozzles. A vehicle with an aerospike nozzle uses less fuel at low altitudes due to its altitude adaptability, where most missions have the greatest need for thrust. Aerospike nozzles are better suited to Single Stage to Orbit (SSTO) missions compared to conventional nozzles. In the current study, the flow through 20% and 40% aerospike nozzle is analyzed in detail using computational fluid dynamics technique. Steady state analysis with implicit formulation is carried out. Reynolds averaged Navier-Stokes equations are solved with the Spalart-Allmaras turbulence model. The results are compared with experimental results from previous work. The transition from open wake to closed wake happens in lower Nozzle Pressure Ratio for 20% as compared to 40% aerospike nozzle.

<b>New butterfly records from the Jammu Shiwaliks, Jammu & Kashmir, India</b>

The Himalayan state of Jammu and Kashmir, owing to variety of habitats, different climatic regimes and a wide range of altitude offers conducive habitats to butterflies ranging from low level hills of Shiwaliks to Trans-Himalayan landscapes of Ladakh through mighty Pir-Panjal and Valley of Kashmir. It is noteworthy that these mountainous landscapes though rich in insect diversity are the least known for butterfly fauna. The present note describes the new records based on opportunistic surveys of butterflies on the sidelines of avian surveys conducted in Jammu Shiwaliks during the years 2015 and 2016.

Vector Transmission Alone Fails to Explain the Potato Yellow Vein Virus Epidemic among Potato Crops in Colombia.

The potato yellow vein disease, caused by the potato yellow vein virus (PYVV), is a limiting potato disease in northern South America. The virus can be transmitted either by the greenhouse whitefly (GWF), Trialeurodes vaporariorum (Westwood) (Hemiptera: Aleyrodidae), or through vegetative propagules, such as infected tubers. Recently, GWF populations have been spotlighted as one of the main drivers of PYVV re-emergence, and consequently, PYVV management has been predominantly directed toward vector control, which is heavily based on insecticide use. However, the drivers of the PYVV outbreaks as well as the contribution of GWF populations on the spread of PYVV among potato crops are still not completely understood. This study aims to assess the role of the GWF as a driver of the PYVV epidemic in the potato-producing areas in Colombia, one of the countries more severely affected by the PYVV epidemic, and whose geography allows the study of the spatial association between the vector and the disease epidemic across a wide altitude range. The geographical clusters where the PYVV epidemic is concentrated, as well as those of farms affected by the GWF were identified using a novel spatial epidemiology approach. The influence of altitude range on the association between PYVV and T. vaporarioum was also assessed. We found a relatively poor spatial association between PYVV epidemic and the presence of the GWF, especially at altitudes above 3,000 m above mean sea level. Furthermore, GWF populations could only explain a small fraction of the extent of the PYVV epidemic in Colombia. Movement of infected seed tubers might be the main mechanism of dispersion, and could be a key driver for the PYVV infection among potato crops. Agricultural policies focused on improving quality of seed tubers and their appropriate distribution could be the most efficient control intervention against PYVV dispersion.