Ground Applications Research Articles

Mamba-VNPS: A Visual Navigation and Positioning System with State-Selection Space

This study was designed to address the challenges of autonomous navigation facing UAVs in urban air mobility environments without GPS. Unlike traditional localization methods that rely heavily on GPS and pre-mapped routes, Mamba-VNPS leverages a self-supervised learning framework and advanced feature extraction techniques to achieve robust real-time localization without external signal dependence. The results show that Mamba-VNPS significantly outperforms traditional methods across multiple aspects, including localization error. These innovations provide a scalable and effective solution for UAV navigation, enhancing operational efficiency in complex spaces. This study highlights the urgent need for adaptive positioning systems in urban air mobility (UAM) and provides a methodology for future research on autonomous navigation technologies in both aerial and ground applications.

Compact clocks & cavities for space and ground applications

Compact clocks & cavities for space and ground applications

EFFECT OF VERMICOMPOST AND BIOFERTILIZATION ON THE AVAILABILITY OF SOME SOIL NUTRIENTS, GROWTH AND YIELD OF SQUASH (Cucurbita pepo L.)

A field experiment was carried out to evaluate the effect of four application methods of vermicompost tea (without application, ground application, foliar spray, combination of - ground application + foliar spray) , four types of biofertilization (without application, Stenotrophomonas maltophilia, Bacillus megaterium, the combination consisting of S. maltophilia + B. megagaterium), and two levels (0, 50%) of the fertilizer recommendation in the availability of some soil nutrients and on the growth and yield of squash using as randomized complete block design with three replications. The results showed that the triple interaction of the combination of application vermicompost tea with the combination of biofertilizer and 50% of mineral fertilizer was effect significantly and gave the highest values for some vegetative growth parameters. Which included the dry weight of the vegetative part, the length and weight of the root, and total yield which amounted 196.35 g plant-1, 65.33 cm, 60.31 g plant-1, 45.14 Mgha-1, respectively. the available of nitrogen, phosphorous and potassium in soil at the end of the experiment, which amounted 60.56, 38.20 and 191.38 mg kg-1soil in comparison with the treatment without addition, which gave the lowest rates.

Effect of probiotics 'Bio-health' and foliar fertilization with zinc sulfate on growth and yield of okra (Abelmoschus esculentus (L.) Moench)

The experiment was conducted in a private field in Jaflawiya, Al-Mishkhab District, Najaf Governorate, for the spring season 2021, to study the effect of soil application with probiotics Bio health and foliar fertilization with aqueous zinc sulfate on some vegetative growth characteristics and yield of okra Husainawia variety. The experiment was a factorial experiment according to Randomized Complete Block Design (R.C.B.D.) with 2 factors and 3 replicates. The first factor was ground application with probiotics Bio health at 3 levels (0, 2500, 5000 g ha-1) and the second factor is the foliar spraying of zinc in (ZnSO4.7H20) using 3 concentrations (0, 75 and 150 mg L-1). Both factors were applied 3 times during the growing season. The first application was in the stage of 4 true leaves and zinc was sprayed a week later. The second and third were 30 and 60 days after the first addition respectively. Analysis of variance (ANOVA) was performed and the averages were compared using the least significant difference test. Least Significant Difference Test (L.S.D.) at 0.05 probability level. The highest results were recorded in the treatment of adding the Bio health at a level of 5000 g ha-1, which led to the highest rates of vegetative growth indicators, quantitative and qualitative yield and chemical indicators, including plant height, leaf area, knot ratio, number of pods, total yield, nitrogen and phosphorous ratio in pods, zinc content in pods and protein % in pods. In general, the ground application of Bio health at 5000 g ha-1 with zinc 150 mg L-1 significantly outperformed most of the single and interaction treatments. It gave the highest significant increase in vegetative growth indicators, yield, chemical and qualitative indicators.

Application timing affects the efficacy of Bacillus thuringiensis subsp. kurstaki against Tortrix viridana in deciduous oak forests

The green oak leaf roller moth, Tortrix viridana, is one of the main defoliators of deciduous oaks in the Mediterranean region. Although aerial applications of Btk-based insecticides represent the most effective method to control the larval populations of this pest at a large spatial scale, the optimal time window for sprayings has not yet been defined. Accordingly, experimental trials were conducted in a Quercus pubescens forest district in Sardinia (Italy) involving both large-scale aerial treatments and small-scale applications from the ground. The aim of our work was to study how different larval development stages and/or sprouting phenological phases of the host trees affect Btk efficacy. Aerial sprayings were conducted in 2003 and 2004 in two different areas of about 300 ha, selected according to altitude and exposure to simulate three different application timings against different larval instars and sprouting phenological phases. From-the-ground applications were carried out in 2021 in a Q. pubescens forest stand by applying Btk-based insecticides at different timings, and the overall Q. pubescens phenological stage and the distribution of T. viridana larval development stages were assessed accordingly. The effectiveness of Btk applications was evaluated by estimating larval mortality 7, and 14 days after aerial applications, and 7, 14 and 21 days after ground applications. Defoliation due to T. viridana was also evaluated at the end of larval development in all years. In both 2003 and 2004, the average larval mortality due to Btk exceeded 80 % two weeks after aerial applications across all application timings. Damage caused by T. viridana varied with Btk application timing, with the later applications showing a higher defoliation than other timings. In ground application experiments, larval mortality significantly increased when Btk was sprayed against a larval population primarily composed of IV instars, which were feeding on sprouts with leaves that were spread out and had not fully developed internodes, thus resulting in a significative reduction of insect damage. Our findings indicate that, in accordance with the strict synchrony between the larval development and the oak flushing, the optimal timing for Btk application against T. viridana can be defined based on the bud burst phenological phase. In particular, the prevalence of sprout with expanding leaf surface allowing insecticidal droplet interception and the simultaneous presence of susceptible larval instars (within the IV), resulted in an increased treatment efficacy.

DME/TACAN Multipath Impact on GNSS L5/E5a Airborne Receivers Part II: Air–Ground Channel Model and Application

DME/TACAN Multipath Impact on GNSS L5/E5a Airborne Receivers Part II: Air–Ground Channel Model and Application

Numerical Modeling of Water Transport in a Microporous Layer-Coated Porous Transport Layer for a Polymer Electrolyte Membrane Water Electrolyzer with an Interdigitated Flow Field for Internal Gas-Liquid Separation

A novel design for interdigitated flow fields in polymer electrolyte membrane electrolyzers has been developed for both ground and space applications. This design separates oxygen and liquid water internally, eliminating the need for water circulators to remove bubbles and external gas-liquid separators with buoyancy. The capillary pressure in the hydrophobic microporous layer (MPL) of the anode porous transport layer facilitates internal separation of oxygen gas and pressurized liquid water. A finite element model (COMSOL Multiphysics) simulates water transport in the MPL, while electrochemical impedance spectra determine the electrochemical kinetic parameters for the model. The model takes into account the oxygen bubble coverage of the cathode, liquid water saturation in the MPL, and the current ratio between liquid water and water vapor at the MPL-cathode layer interface. The vapor from liquid water in the MPL is modeled to mix with oxygen for diffusion. A volumetric water evaporation rate as a linear function of liquid water saturation in the MPL is assumed, where the rate constant is estimated from vapor permeation tests.

Numerical Modeling of Water Transport in a Microporous Layer-Coated Porous Transport Layer for a Polymer Electrolyte Membrane Water Electrolyzer with an Interdigitated Flow Field for Internal Gas-Liquid Separation

A novel design for interdigitated flow fields in polymer electrolyte membrane electrolyzers has been developed for both ground and space applications. This design separates oxygen and liquid water internally, eliminating the need for water circulators to remove bubbles and external gas-liquid separators with buoyancy. The capillary pressure in the hydrophobic microporous layer (MPL) of the anode porous transport layer facilitates internal separation of oxygen gas and pressurized liquid water. A finite element model (COMSOL Multiphysics) simulates water transport in the MPL, while electrochemical impedance spectra determine the electrochemical kinetic parameters for the model. The model takes into account the oxygen bubble coverage of the cathode, liquid water saturation in the MPL, and the current ratio between liquid water and water vapor at the MPL-cathode layer interface. The vapor from liquid water in the MPL is modeled to mix with oxygen for diffusion. A volumetric water evaporation rate as a linear function of liquid water saturation in the MPL is assumed, where the rate constant is estimated from vapor permeation tests.

A novel large-scale direct shear apparatus considering size effects on strength of frozen coarse-grained soils

As engineering activities in cold regions expand and the application of artificial ground freezing technology in constructions grows, understanding the strength of frozen coarse-grained soils has become imminently crucial. While existing research and testing methods have provided valuable opinions into the behavior of coarse-grained materials in frozen states, there is a recognized need to enhance and expand these methods to gain a more comprehensive understanding of how size effects influence the strength of these materials. To further investigate this issue, a novel large-scale direct shear apparatus was employed to determine the shear strength of frozen coarse-grained soil materials. The apparatus features a unique design capable of accommodating square specimens with five different section lengths: 100 mm, 150 mm, 200 mm, 250 mm, and 300 mm. Depending on the maximum load requirements and budget constraints of the experiment, the equipment can provide a maximum normal stress of 5.5–50 MPa and a maximum shear stress of 3.5–30 MPa for different sample sizes, along with precise temperature control down to −30 °C. The efficacy of the device is validated through experiments conducted on frozen coarse-grained soil samples with specific particle size distributions. This study presents the technological details involved in the development of the apparatus and offers preliminary insights into the strength characteristics of frozen coarse-grained soils, highlighting the influence of size effects. The innovative features of the apparatus help the geotechnical community to comprehensively understand the strength characteristics of this complex material, thereby improving the reliability of engineering practices that involve it.

Parametric study of a vortex-enhanced supersonic inductive plasma torch

The feed gas injection configuration in radio-frequency (RF) inductively coupled plasma (ICP) torches plays a critical role in discharge stability, gas heating, and device thermal management: particularly if a supersonic nozzle is used to subsequently accelerate the hot gas. A novel injection configuration is the bidirectional vortex, which segments the internal ICP flow field into two counter-propagating vortices that can significantly enhance gas heating and reduce heat losses. The diameter of the interface between the vortices (known as the mantle) is expected to be an important dimensional parameter affecting torch operation, especially relative to the nozzle size. In this work, we investigate the effect of nozzle throat diameter on the behaviour and performance of a vortex-enhanced supersonic ICP torch. The system is operated at RF powers and argon mass flow rates between 200–1000 W and 0–400 mg s−1 respectively, and different nozzle diameters ranging from 1.5 to 4 mm are explored. Because of the high-temperature environment, and to prevent disruption of the vortex flow fields, non-invasive diagnostics are used to measure the gas temperature and plasma density, and to infer the torch thermal efficiency and achievable gas specific enthalpy change. The maximum temperature is between 8500–9500 K with the 1.5 mm nozzle giving the highest temperature for a given power and mass flow rate, while plasma densities vary between 1020–1021 m−3 depending on the operating conditions. The thermal efficiency increases from 29% for the 1.5 mm nozzle to just above 70% for the 4 mm nozzle with a similar maximum specific enthalpy of around 1.5 MJ kg−1. These results demonstrate the important coupling between torch properties, and how system optimization can lead to tailored performance of potential interest to several ground and space-based applications.

Fabrication and characterization of recycled construction waste bricks modified with sisal fibers

The study presents an investigation into the preparation and characterization of modified hemp fiber reinforced recycled construction waste bricks for ground and road applications. By incorporating 1 % hemp fiber and a 70/30 ratio of recycled concrete aggregate to recycled brick aggregate, the optimal combination was identified, resulting in a maximum compressive strength of 36.2 MPa, a 38.7 % improvement over the control bricks. The addition of 2 % hemp fiber increased the flexural strength by 85.7 %, while the thermal conductivity decreased by 41.5 % with the inclusion of 2 % hemp fiber and 100 % recycled brick aggregate. Scanning electron microscopy and X-ray diffraction analysis confirmed the compatibility of hemp fibers with the cement matrix and their role in enhancing the microstructure of the bricks and hydration process. These findings highlight the potential of hemp fiber-reinforced recycled waste bricks as environmentally friendly high-performance materials for sustainable ground and road construction.

Effect of Ground Application and Foliar Nutrition with Yeast on Vegetative Growth Characteristics of Hot Pepper Plants Capsicum annuum L.

Effect of Ground Application and Foliar Nutrition with Yeast on Vegetative Growth Characteristics of Hot Pepper Plants Capsicum annuum L.

Adjuvant use for the management of pesticide drift, leaching and runoff.

Adjuvants are included in many pesticide spray mixtures to enhance the performance of the applied chemical. Many adjuvants which modify the emulsion or extensional viscosity of the tank-mixture have been found to offer benefits in drift management, primarily by eliminating or reducing the 'Fine' droplets included in the spray with diameters <100-200 μm that can move off-target in unfavorable conditions during ground, airblast and aerial pesticide applications. Among wind tunnel and field studies conducted around the world, there is consensus that while some adjuvants are effective for drift management, the performance varies on a case-by-case basis, requiring verification for each adjuvant which could be achieved through a programme such as certification based on showing a reduction in Fine droplets and/or a reduction in airborne drift. These can be measured in wind tunnel studies according to international standards. This article provides a review of the current science in this subject area, from the approaches to data collection to a review of existing data and regulatory application for encouraging and rewarding the use of appropriate adjuvants that have been demonstrated to reduce airborne spray drift potential and therefore the size of no-spray buffer zones appropriate to protect nontarget sensitive areas from drift exposure. Some adjuvants can offer the same reduction in drift as offered by hooded sprayer retrofits. A drift reduction programme based on adjuvant use could include testing candidate adjuvants for their effect on droplet size and reduction in Fine droplets when sprayed through reference nozzles and compared against sprays without the adjuvant. Testing could also be based alternatively on measurements of drift potential on collectors such as monofilament line in wind tunnel or field studies. Once shown to be effective in reducing 'Fines' or spray drift, adjuvants could be certified and then referenced on pesticide labels and/or regulatory or best management practice schemes to encourage their use and offer reductions in use restrictions or no-spray buffer zone sizes based on drift management. Studies have shown that some adjuvants can reduce pesticide leaching into soils and contamination of groundwater, as well as runoff of active ingredients from plants into the environment. Performance depends on the adjuvant type, the pesticide with which it is used, the soil or plant type, the timing and mass of water input from rainfall and climatic factors. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Single-photon detection using large-scale high-temperature MgB2 sensors at 20 K

Ultra-fast single-photon detectors with high current density and operating temperature can benefit space and ground applications, including quantum optical communication systems, lightweight cryogenics for space crafts, and medical use. Here we demonstrate magnesium diboride (MgB2) thin-film superconducting microwires capable of single-photon detection at 1.55 μm optical wavelength. We used helium ions to alter the properties of MgB2, resulting in microwire-based detectors exhibiting single-photon sensitivity across a broad temperature range of up to 20 K, and detection efficiency saturation for 1 μm wide microwires at 3.7 K. Linearity of detection rate vs incident power was preserved up to at least 100 Mcps. Despite the large active area of up to 400 × 400 μm2, the reset time was found to be as low as ~ 1 ns. Our research provides possibilities for breaking the operating temperature limit and maximum single-pixel count rate, expanding the detector area, and raises inquiries about the fundamental mechanisms of single-photon detection in high-critical-temperature superconductors.

Determining the effect of non-condensable gas on a two-phase ammonia heat transfer loop of the satellite

It is advisable to design thermal management systems for high-power stationary satellites and specific ground applications using two-phase mechanically pumped loops with ammonia as the coolant. During prolonged operation in orbit, the accumulation of non-condensable gases can occur due to radiolysis and chemical reactions. The issues related to the effect of non-condensing gas on system parameters and performance have not yet received sufficient attention. The study of the distribution of non-condensable gas in the loop was performed by calculation-theoretical and experimental methods in a heat transfer loop with a Heat-Controlled Accumulator. Part of the gas accumulates in the steamgas zone of the Heat-Controlled Accumulator and affects the pressure value at a set temperature. The other gas is dissolved in liquid ammonia. This impacts the overheating of the cooled device when the heat load is switched on, the heat transfer intensity during boiling, and the cavitation reserve at the pump inlet. Accumulation of non-condensable gas up to ~0.075 mol nitrogen/kg ammonia, concentration of dissolved gas in the liquid up to ~5.3⋅10–4 mol/mol of the mixture does not significantly impact the parameters and performance of the system. But, if the aim is to precisely ensure the boiling temperature of the coolant or the cavitation reserve, the amount of necessary correction of the control parameters is up to 2.5 K. The results of the investigation can be used in the design of two-phase heat transfer loops for satellites and other applications, in particular, for the selection of the design and location of gas traps

Investigation on the Influence of the Condenser Length and Its Coupling Effect With Elevation on the Performance of Loop Heat Pipe

Abstract The effects of condenser length and evaporator/condenser elevation on the performance of a loop heat pipe (LHP) in a gravity field were investigated, respectively, as well as their coupling effect. The refrigerant R40 was selected, and the condenser length was altered by changing the number of fins connected to the water-cooled plates. The experiments were conducted at three evaporator/condenser elevations: zero elevation, favorable elevation, and adverse elevation. The experimental results indicated that the evaporator temperatures of LHP with three different condenser lengths are very close when the LHP operates in variable conductance mode (VCM). However, an excessively long condenser will increase the LHP thermal resistance in VCM. In constant conductance mode (CCM), the longer the condenser, the lower the evaporator temperature. As the heat load increases, the LHP first exhibits gravity-driven mode and then capillarity-gravity-driven mode at a favorable elevation. The positive coupling effect on reducing the evaporator temperature by extending the condenser length and running at a favorable elevation manifests that the influence of condenser length is very small in gravity-driven mode, while in capillarity-gravity-driven mode, the effect of operating at a favorable elevation gets weakened, and the positive effects of the two factors cannot be simply calculated by the linear superposition principle. Additionally, reverse flow and flash evaporation were also observed and analyzed in depth. These results and conclusions can be used to guide the design of the condenser and the installation of LHP for ground applications.

Benefits of ULV Application to Control Locusts in Caucasus and Central Asia

This paper discusses the state-of-the-art of Ultra-Low Volume (ULV) spray application with rotary atomisers in the Caucasus and Central Asian (CCA) region to control locusts. The technology is widely used around the world for locust control and promoted by the UN Food and Agriculture Organisation (FAO) as an effective and efficient control intervention that meets the scale and challenge posed by large area locust outbreaks. The technology utilises precisely controlled spray droplets in the range 50–100um using ready-to-use oil-based ULV formulations to target locusts more efficiently. Volume rates as low as 0.5–1.0 l/ha are utilised which greatly improves productivity of ground and aerial spray applications, timeliness, and reduces cost and waste of pesticide and water. ULV has become more widely adopted in CCA during recent years to control major economic pests such as Moroccan, Italian, and Asian migratory locusts. Its further adoption is hampered by the lack of available ULV formulations in the region and need for investment and training in the technology. ULV technology is highly appropriate for use of biological products to reduce risks to operators and the environment and efforts to increase regional cooperation and the registration of safer pesticides across the region present opportunities for its wider adoption.

Review of Ground Penetrating Radar Applications for Bridge Infrastructures

Infrastructure bridges play a crucial role in fostering economic and social development. However, the adverse effects of natural hazard and weather degradation, coupled with escalating rates of traffic, pose a significant threat. The resultant strain on the structure can lead to undue stress, elevating the risk of a critical asset failure. Hence, non-destructive testing (NDT) has become indispensable in the surveillance of bridge infrastructure. Its primary objectives include ensuring safety, optimizing structural integrity, minimizing repair costs, and extending the lifespan of bridges. NDT techniques can be applied to both existing and newly constructed bridge structures. However, it is crucial to recognize that each NDT method comes with its own set of advantages and limitations tailored to specific tasks. No single method can provide an effective and unequivocal diagnosis on its own. Among the various NDT methods, Ground Penetrating Radar (GPR) has emerged as one of the most widely employed techniques for monitoring bridges. In fact, recent technical regulations now mandate the use of GPR for bridge monitoring and characterization, underscoring its significance in ensuring the structural health and longevity of these critical infrastructures. Ground Penetrating Radar (GPR) stands out as one of the most highly recommended non-destructive methods, offering an efficient and timely assessment of the structural conditions of infrastructure. Recognizing the pivotal role of non-destructive testing (NDT) in this context, this paper aims to elucidate recent scientific endeavors related to the application of GPR in bridge engineering structures. The exploration will commence with a focus on studies conducted both at the model level within laboratory settings and on real cases. Subsequently, the discussion will extend to encompass the characterization and monitoring of the bridge’s main elements: slab, beam, and pillar. By delving into these scientific experiences, this paper intends to provide valuable insights into the efficacy and applicability of GPR in assessing and ensuring the structural integrity of bridges. This paper provides a concise survey of the existing literature on the application of Ground Penetrating Radar (GPR) in the assessment of bridges and viaducts constructed with masonry and reinforced concrete, taking into account papers of journal articles and proceedings available on open databases. Various approaches employed in both laboratory and field settings will be explored and juxtaposed. Additionally, this paper delves into discussions on novel processing and visualization approaches, shedding light on advancements in techniques for interpreting GPR data in the context of bridge and viaduct evaluations.

Chitosan combined with humic applications during sensitive growth stages to drought improves nutritional status and water relations of sweet potato

The current decline in freshwater resources presents a significant global challenge to crop production, a situation expected to intensify with ongoing climate change. This underscores the need for extensive research to enhance crop yields under drought conditions, a priority for scientists given its vital role in global food security. Our study explores the effects of using humic and chitosan treatments to alleviate drought stress during critical growth phases and their impact on crop yield and water efficiency. We employed four different irrigation strategies: full irrigation, 70% irrigation at the early vine development stage, 70% irrigation during the storage root bulking stage, and 85% irrigation across both stages, complemented by full irrigation in other periods. The plants received either humic treatments through foliar spray or soil application, or chitosan foliar applications, with tap water serving as a control. Our findings highlight that the early vine development stage is particularly vulnerable to drought, with a 42.0% decrease in yield observed under such conditions. In normal growth scenarios, foliar application of humic substances significantly improved growth parameters, resulting in a substantial increase in yield and water efficiency by 66.9% and 68.4%, respectively, compared to the control treatment under full irrigation. For sweet potatoes irrigated with 70% water at the storage root bulking stage, ground application of humic substances outperformed both foliar applications of chitosan and humic in terms of yield results. The highest tuber yield and water efficiency were attained by combining chitosan and humic ground applications, regardless of whether 70% irrigation was used at the storage root bulking stage or 85% irrigation during both the early vine development and storage root bulking stages.

Control of Urochloa decumbens Using Glyphosate Applied by Remotely Piloted Aircraft and Ground Sprayer with Different Spray Nozzles.

The use of remotely piloted aircraft (RPA) to spray pesticides currently occurs, but knowledge about this technology is lacking due to the different locations, targets, and products applied. The objective of this study was to evaluate the control of Urochloa decumbens with glyphosate applied using an RPA (10 L ha-1) equipped with different spray nozzles (XR 11001 and AirMix 11001). For the purpose of comparison, ground application was also performed (100 L ha-1). The deposition was evaluated by means of the quantification of a tracer by spectrophotometry, the droplet spectrum was evaluated with water-sensitive paper, and the control efficiency was evaluated based on visual measurements with percentage scores. Statistical process control was used to analyse the quality of the deposition in the area. The results showed that the application via RPA presented a greater amount of tracer on the leaves than the ground application, suggesting that the former is a good option for application, even providing a lower coverage and number of droplets per area. Both application methods were effective at controlling Urochloa decumbens. The nozzles showed potential for use in applications, with control efficiency higher than 84% from 21 days after application. The percentage of droplets smaller than 100 μm in the applications was less than 5%. No nonrandom behaviour was observed during deposition, indicating a high-quality process.