Ground Applications Research Articles

A Thermal, Mechanical, and Materials Framework for a Shape Memory Alloy Heat Engine for Thermal Management.

Shape memory alloy (SMA) heat engines possess an inherent property of sensing a change in temperature, performing work, and rejecting heat through the shape memory effect resulting from a temperature-induced phase transformation. This work presents a framework for the design and implementation of an SMA-based Stirling heat engine for maximum torque or speed incorporating and combining mechanical, thermal, and material aspects. There is a growing need for such engines for reliable thermal management and energy recovery in both ground and space applications. Mechanical aspects were addressed from force balances in the SMA element and focused on the resulting stress distribution. Thermal aspects considered heat transfer between the SMA element and both the heat source and the heat sink. Materials aspects considered the chemical, elastic, and frictional contributions to the enthalpy of the transformation. The roles of nano- and microstructure through composition, precipitates, variant interfaces, training, cycling, texture, defects, nucleation sites (bulk vs. surface), and multi-step transformations (e.g., a trigonal R-phase transformation) in NiTi based-alloys are also emphasized. The aforementioned aspects were combined to present a figure of merit to aid in the design and implementation of a Nitinol Stirling heat engine operating to maximize torque or maximize speed.

Effect of Flow Resistance of Floating-Type Check Valves on Heat Transfer Characteristics of an Oscillating Heat Pipe

Abstract An oscillating heat pipe with check valves (CVOHP) is an attractive heat transfer device for future spacecraft with considerable heat dissipation and ground applications. This study aims to clarify the effect of the flow resistance of floating-type check valves on the heat transfer characteristics of the CVOHP using a one-dimensional slug flow model, which simulates the five-turn CVOHP used in the on-orbit experiment by the authors. The numerical simulations were conducted for different flow resistances, positions, and numbers of check valves. The results showed that the thermal resistance of the CVOHP increases with the flow resistance of the check valves, while there is no significant effect on the startup characteristics. The thermal resistance increased by more than 100% in the worst case, and the recommended flow resistance coefficient of the check valve was below 100 in this study for high thermal performance. The thermal resistance increases with an increasing number of high-resistance check valves but is less affected by the position of the valve. Additionally, the higher the heat input, the greater the effect of the flow resistance of the check valves. According to the findings in this study, it is necessary to control the flow resistance of the floating-type check valves at a low level for the high thermal performance of a CVOHP.

PENGARUH APLIKASI KOMPOS CAMPURAN AMPAS KOPI DAN TEPUNG CANGKANG TELUR TERHADAP KADAR NITROGEN DAN KALSIUM TANAH REGOSOL SERTA PERTUMBUHAN DAN HASIL TANAMAN OKRA (Abelmoschus esculentus L.)

One of the medicinal plants that are rarely cultivated in Indonesia is okra. This plant has a business opportunity that can bring benefits to farmers. This research aimed to elucidate the effect of a compost mixture of coffee grounds and milled eggshell on nitrogen and calcium contents in a regosol soil and growth and yield of okra plants. Fertilizer treatments tested were: P0 (control), P1 (100% inorganic), P2 (25% compost + 75% inorganic), P3 (50% compost + 50% inorganic ), P4 (75% compost + 25% inorganic), and P5 (100% compost). The results showed that the application of a compost mixture of coffee grounds and eggshell with a dose of 100% compost had a significant effect on increasing soil pH, total N, and Ca compared to control, namely 30,77%, 147,52%, and 643,54%, but did not significantly affect the organic C of the soil. The application of coffee grounds and milled eggshell compost with a dose of 100% significantly affected plant height at 8 WAP and plant stem diameter at 6 WAP. The application of coffee grounds and milled eggshell compost with a dose of 100% significantly increased fresh fruit weight and dry weight of okra plants, respectively 18.27% and 33.33% compared to the control.

Vacuum-Seal Waveguide Feedthrough for Extended W-Band 67–116 GHz

This article describes the design and performance of a vacuum-seal waveguide feedthrough with ultrawide RF band 67–116 GHz. We describe first the initial drivers behind the chosen design, then we present the results of the numerical simulations and optimization and provide thereafter the results of the RF and vacuum tests of the fabricated devices. The demonstrated RF performance is very close to the one expected from the simulation with an insertion loss less than 0.3 dB and a return loss better than 20 dB. Simultaneously, the feedthrough shows excellent vacuum isolation, Helium gas leak rate of < 2x10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">−8</sup> mbar·L/s is demonstrated, which allows using such a device in various space and ground applications.

Analysis of the impact of climate change on the factors determining the flow of meltwater in the steppe zone of the Saratov region

The paper analyzes the influence of protective measures, seed dressing and ground processing of non-narcotic hemp fields on the morphometric parameters of plants, damage by pests and diseases, and crop yield. The article focuses on the effect of dressing agents in various combinations on the growth processes of cannabis seeds in the early stages of development. In tests, laboratory and field, seed treatments with Benorade and Celeste Top played the greatest stimulating role. The best results in reducing plant damage by Psylloides attenuate (Koch) 66.7 and 60.0% with a duration of protection of up to four to five pairs of leaves were obtained with the use of Tabu + Albit preparations for seed treatment and Samurai Super insecticide for ground application. With the help of Celeste Top in combination with the studied fungicides, root rot was suppressed, while the prevalence of the disease was reduced by 24.4 and 24.8% compared with the absolute control. A high increase in the yield of stems was guaranteed by the treatment of plants with an insecticide and seeds with Celest Top preparations in combination with Albit and Benorad 2.19 and 2.10 t/ha. A significant increase in seed yield was recorded in the variants when seeds were disinfected with the developed compositions Bunker + Celeste Top, Taboo and Benorade + Celeste Top 0.29 and 0.24 t/ha with the involvement of an insecticide during ground cultivation of the crop.

Efficacy and nontarget effects of broadcast treatments to manage spotted lanternfly (Hemiptera: Fulgoridae) nymphs.

Management to control the spotted lanternfly, Lycorma delicatula (White), would ideally achieve managers' goals while limiting impacts on nontarget organisms. In a large-scale field study with 45 plots at least 711 m2, we tested foliar applications of dinotefuran and 2 formulations of Beauveria bassiana (Balsamo) Vuillemin, each applied from the ground and separately by helicopter. Applications targeted early instar nymphs. For both application methods, a single treatment with dinotefuran significantly reduced L. delicatula numbers, as measured by catch on sticky bands (91% reduction by air and 84% reduction by ground 19 days after application) and by timed counts (89% reduction by air and 72% reduction by ground 17 days after application). None of the B. bassiana treatments significantly reduced L. delicatula numbers, even after 3 applications. Beauveria bassiana infection in field-collected nymphs ranged from 0.4% to 39.7%, with higher mortality and infection among nymphs collected from ground application plots. Beauveria bassiana conidia did not persist for long on foliage which probably contributed to low population reduction. Nontarget effects were not observed among arthropods captured in blue vane flight intercept traps, San Jose Scale pheromone sticky traps or pitfall traps, but power analysis revealed that small reductions of less than 40% may not be detected despite extensive sampling of 48,804 specimens. These results demonstrate that dinotefuran can markedly reduce local abundance of L. delicatula with little apparent effect on nontarget insects when applied shortly after hatch, and that aerial applications can match or exceed the effectiveness of applications from the ground.

The effectiveness of various methods of protection against hemp flea and the use of dressing from root rot in the hemp cultivation

The paper analyzes the influence of protective measures, seed dressing and ground processing of non-narcotic hemp fields on the morphometric parameters of plants, damage by pests and diseases, and crop yield. The article focuses on the effect of dressing agents in various combinations on the growth processes of cannabis seeds in the early stages of development. In tests, laboratory and field, seed treatments with Benorade and Celeste Top played the greatest stimulating role. The best results in reducing plant damage by Psylloides attenuate (Koch) 66.7 and 60.0% with a duration of protection of up to four to five pairs of leaves were obtained with the use of Tabu + Albit preparations for seed treatment and Samurai Super insecticide for ground application. With the help of Celeste Top in combination with the studied fungicides, root rot was suppressed, while the prevalence of the disease was reduced by 24.4 and 24.8% compared with the absolute control. A high increase in the yield of stems was guaranteed by the treatment of plants with an insecticide and seeds with Celest Top preparations in combination with Albit and Benorad 2.19 and 2.10 t/ha. A significant increase in seed yield was recorded in the variants when seeds were disinfected with the developed compositions Bunker + Celeste Top, Taboo and Benorade + Celeste Top 0.29 and 0.24 t/ha with the involvement of an insecticide during ground cultivation of the crop.

Multivariate Analysis Applied to the Ground Application of Pesticides in the Corn Crop

Including the correct combination of factors for the application technology of pesticides can improve their distribution on their targets. The aim of this work was to use multivariate analysis to study the effect size and the order of influence of three factors that interfere with pesticide application technology in corn crops. A 2 × 2 × 3 factorial experiment was conducted with two droplet size classes (fine and coarse), two application rates (80 and 150 L ha−1), and the presence of adjuvants (mineral oil one and two, and no adjuvant). A knapsack boom sprayer was used for the applications. Droplet deposition on the corn leaves was evaluated by detecting a tracer added to the spray via spectrophotometry and the droplet spectrum by analyzing water-sensitive papers. Univariate and multivariate statistical analyses were performed to integrate the variables analyzed. Droplet size has proven to be the most important factor in spraying planning, and the second factor is the application rate. With the association between fine droplets and higher application rates, a better performance was obtained in coverage, droplet density, and droplet deposition.

Application of Air-Coupled Ground Penetrating Radar Based on F-K Filtering and BP Migration in High-Speed Railway Tunnel Detection.

As the number and length of high-speed railway tunnels increase in China, implicit defects such as insufficient lining thicknesses, voids, and poor compaction have become increasingly common, posing a serious threat to train operation safety. It is, therefore, imperative to conduct a comprehensive census of the defects within the tunnel linings. In response to this problem, this study proposes a high-speed railway tunnel detection method based on vehicle-mounted air-coupled GPR. Building on a forward simulation of air-coupled GPR, the study proposes the F-K filtering and BP migration algorithms based on the practical considerations of random noise and imaging interference from the inherent equipment. Through multi-dimensional quantitative comparisons, these algorithms are shown to improve the spectrum entropy values and instantaneous amplitude ratios by 4.6% and 11.6%; and 120% and 180%, respectively, over the mean and bandpass filtering algorithms, demonstrating their ability to suppress clutter and enhance the internal signal prominence of the lining. The experimental results are consistent with the forward simulation trends, and the verification using the ground-coupled GPR detection confirms that air-coupled GPR can meet the requirements of high-speed railway tunnel lining inspections. A comprehensive GPR detection model is proposed to lay the foundation for a subsequent defect census of high-speed railway tunnels.

Mathematical Solution of Temperature Field in Non-Hollow Frozen Soil Cylinder Formed by Annular Layout of Freezing Pipes

With the wide application of the artificial ground freezing method in municipal underground engineering, the annular layout of freezing pipes is often adopted to form a frozen soil cylinder. However, there is still no analytical solution that can calculate the temperature distribution of frozen soil formed in this case. In this paper, a mathematical model of a steady-state temperature field of single-circle freezing is established, in which the inside of the freeze ring is completely frozen; that is, the temperature of all excavation sections is below the freezing point. Then, the analytical solution of temperature distribution is deduced through the complex variable method and potential superposition method. Comparison results of the analytical solution with those of the numerical simulation show that the analytical solution is precise enough. The temperature distribution of the main section and the intersection is approximately the same on the inner side, but the freezing effect of the main section is relatively better near the freezing pipes and outside the freeze ring. Besides, according to the derived analytical solution and common freezing parameters, a simplified formula to calculate the temperature field with enough accuracy was proposed, and the error can be controlled below 1‰. Finally, based on the simplified formula, a calculation method for frozen soil thickness and the average temperature is also given in this paper.

Effect of Ground Addition of Seaweed Extract and NPK Fertilizer on the Vegetative Growth Characteristics of Aloe vera L.

To investigate the impact of ground application of seaweed extract and NPK fertilizer on some vegetative growth characteristics of Aloe vera, an experiment was conducted during the agricultural season (2021-2022) in the wooden canopy of the Department of Horticulture and Garden Engineering at the College of Agriculture / University of Karbala. The experiment had two factors: the addition of fertilizer to the neutralized NPK at three concentrations (4, 2, 0) g.L-1, and the employment of an environmentally friendly nutritional program by adding seaweed powder to the chemical program of adding NPK fertilizer neutralized 20:20:20 L-1. The following emerged from the experiment’s findings: (1) The ground addition of seaweed extract of the aloe vera plant led to a significant increase in all vegetative characteristics when treated T3 concentration (3 g. L-1) (plant height 32.11 cm, leaf thickness 10.93 mm, number of leaves 12.56 leaves plant-1, fresh weight 167.78 g, leaf dry weight 55.89 g). (2) The results showed that the addition of the neutral NPK fertilizer to the aloe vera plant at a concentration of (4 g / l-1) when treated, showed significant differences in all vegetative growth characteristics (plant height (30.60) cm ،the thickness of the leaf is 9.86 mm, the number of leaves is 12.11 leaves. Plant, the fresh weight is 158.00 g, the dry weight of the leaf is 52.53 g). (3)The binary interaction between the addition of seaweed extract and NPK fertilizer when the interaction T3N4 (4g/l-1 + 3 4g/l-1) showed significant differences in all vegetative characteristics of aloe vera plant، (Plant height 34.83 cm, leaf thickness 12.73 mm, number of leaves 15.00 leaf. Plant, fresh weight 174.33 gm, dry weight 58.07 gm.

Dissociation between phase and power correlation networks in the human brain is driven by co-occurrent bursts

Well-known haemodynamic resting-state networks are better mirrored in power correlation networks than phase coupling networks in electrophysiological data. However, what do these power correlation networks reflect? We address this long-outstanding question in neuroscience using rigorous mathematical analysis, biophysical simulations with ground truth and application of these mathematical concepts to empirical magnetoencephalography (MEG) data. Our mathematical derivations show that for two non-Gaussian electrophysiological signals, their power correlation depends on their coherence, cokurtosis and conjugate-coherence. Only coherence and cokurtosis contribute to power correlation networks in MEG data, but cokurtosis is less affected by artefactual signal leakage and better mirrors haemodynamic resting-state networks. Simulations and MEG data show that cokurtosis may reflect co-occurrent bursting events. Our findings shed light on the origin of the complementary nature of power correlation networks to phase coupling networks and suggests that the origin of resting-state networks is partly reflected in co-occurent bursts in neuronal activity.

Evaluating control methods for red imported fire ant and their effects on hibiscus mealybug in citrus

AbstractThe red imported fire ant (Solenopsis invicta) may disrupt biological control of hibiscus mealybug (Nipaecoccus viridis) in Florida citrus. Controlling S. invicta may therefore be necessary for effective management of hibiscus mealybug. We evaluated four different methods to control S. invicta (ground applications of insecticide, two different insecticidal ant baits and spot‐treating ant colonies with hot water) to determine how these different treatments affected ants tending to hibiscus mealybug colonies, natural enemy abundance within hibiscus mealybug colonies and hibiscus mealybug colony abundance. While all treatments reduced the number of S. invicta colonies in treated areas compared to an untreated control, only ground applications of insecticide and the two ant baits significantly reduced the abundance of S. invicta found tending hibiscus mealybug colonies. Additionally, significantly more Brachymyrmex obscurior ants were found tending mealybug colonies in plots treated with either of the two ant baits. There was no significant effect of treatment on the abundance of natural enemies in hibiscus mealybug colonies, but significantly fewer natural enemies were found in mealybug colonies tended by S. invicta, and significantly more natural enemies were found in mealybug colonies tended by B. obscurior. Ground applications of insecticide, the abamectin ant bait Clinch and hot water treatments all reduced the overall number of hibiscus mealybug colonies compared with control areas, while the S‐methoprene ant bait Extinguish did not. Our results suggest that reducing the number of S. invicta tending hibiscus mealybug colonies can lead to higher natural enemy abundance and lower hibiscus mealybug abundance. However, methods used to control S. invicta may have different impacts on ant species like B. obscurior, leading to different outcomes with natural enemies.

Prediction and Analysis of Formation and Development Characteristics of Frozen Soil Wall: A Case Study on the Chengjiao East Ventilation Shaft Repair

Due to their advantages, artificial ground freezing methods are widely used in deep shaft construction and repair with the continuous exploitation of coal and other mineral resources. The boundary convection due to ventilation conditions will affect the formation and development of this frozen soil wall, which needs to be studied systematically. Thus, in this study, a numerical calculation model of a freezing temperature field was established based on the actual conditions of the east ventilation shaft in the Chengjiao coal mine during repair by the freezing method, and the temperature and thickness laws of the frozen soil wall and the shaft wall were studied by changing the influencing parameters. The results indicated that the thickness of the outside position gradually exceeded that of the inside position of the frozen soil wall due to the ventilation effect, and the difference between these two parameters was approximately 0.2~0.3 m, while the temperature difference was no more than 1 °C. The frozen soil wall did not complete a cross-loop within 180 d under ventilation conditions when the freezing tube pitch exceeded a certain threshold, which was about 2.3~2.5 m for this ventilation shaft. The soil moisture content played an important role in the initial freezing under ventilation conditions in the full combination calculation. This paper provides theoretical support for studying the application of the artificial ground freezing method for shaft construction and repair under ventilation conditions.

A comprehensive review on unethical honey: Validation by emerging techniques

Globally, honey is consumed as natural functional food, featuring high economic value, related to its authenticity and purity. Due to the high demand for honey, it has been wildly targeted for food adulteration with substandard honey or low-price syrups, and emerging absorbent resin technology has also affected the honey market. Researchers worldwide have been working persistently to invent and innovate advanced technologies for detecting honey adulteration and assuring its authenticity. The compositional intricacy of pure and unauthentic honey could be easily detangled by a combined approach of chemometrics and instrument. In this palimpsest, various detection methods like ISCIRA, NMR, AT-FTIR, Sensors, PCR based assay united with an appropriate Multivariate approach that provides accurate and acceptable results for the determination of honey authentication and adulteration were described. The botanical origin authentication of honey was determined with the application of δ13C-EA-IRMS and δ13C-LC-IRMS coupled SVM, which discriminate samples based on specific markers. LIBS, NMR, HPTLC, UHPLC, GC, and real-time PCR, generated data and processed with LDA, OPLS, PCA, ANN, CNN etc. The generated data discriminate adulterated honey from pure, as NMR clubbed with PCA can detect 1% of adulterants in honey. Hence, various methodologies in chemometrics have manifested their proficiency during ground application. Perhaps, there is a long way to go in this field to develop a universal technology for honey authentication and adulteration detection.

Вплив конструктивних параметрів термоплати на гістерезис за тепловим навантаженням

The contact heat exchangers designed to remove heat from the cooled devices are used in mechanically pumped two-phase loops of thermal management systems for ground and space applications, a thermoplate (heat sink). After the device is turned on, it may overheat abnormally during the process of reaching a stationary operating mode. Overheating is associated with the phenomenon of thermal load hysteresis during the onset of boiling, the transition from single-phase convection to developed boiling in the evaporator of a heat sink material. This work studied the influence of the construction parameters of thermoplate on the hysteresis phenomenon at the integral level. For this purpose, a thermoplate testing methodology was implemented, which includes experiments with slow (quasi-stationary) and quick heating after turning on the device immediately at full power. Overheating of the device is possible during both "slow" and "quick" heating. The maximum overheating in the experiments performed was ~18 K. Such overheating can pose a danger to the reliability of the device. The study was performed with ammonia as a coolant on 5 models of thermoplate that differ in evaporator channel roughness, length, material, longitudinal thermal conductivity, the heat capacity of the structure, etc. The danger of overheating the device is also determined by the maximum thermal load at which the device is operated. The following conclusions were made: the greatest influence on the hysteresis parameters is the value of the evaporator channel surface roughness. Increasing the roughness reduces the risk of overheating the device, and changes the nature of the "boiling curves" in the thermoplate; an increase in the length and longitudinal thermal conductivity has a favorable effect on reducing the risk of overheating; the evaporator surface is made of aluminum alloy instead of stainless steel, which makes hysteresis impossible; in the case of rapid heating of the thermoplate, the maximum heat flux at steady-state has an ambiguous effect: with its increase, overheating due to hysteresis first increases, and in the case of further increase, it decreases and may disappear altogether. A significant increase in the maximum heat flux compared to the heat flux at the beginning of boiling reduces the danger of hysteresis affecting the overheating of the device. The results of this work provide recommendations on how to avoid the dangerous overheating of the device due to the hysteresis phenomenon.

Use of screw pile foundations to reduce temperature of warming permafrost: Lab tests and numerical modeling

Steel screw piles may be a viable pile foundation type in the permafrost region of the Canadian Arctic but the effects of climate change may accelerate the creep settlement rate of the pile. Reducing the temperature around a pile is an effective way of enhancing the long-term performance of a pile. This study proposes a technique that combines the steel screw pile with the artificial ground freezing method, where liquid coolant is circulated through the hollow screw pile shaft to lower the temperature of surrounding permafrost. A series of laboratory experiments of freezing tests was conducted to verify the feasibility of the proposed technique. A finite element model was then developed to evaluate the cooling effect of this technique by analysing the duration of the permafrost freezing and the power of removing the heat from the soil. The numerical model was calibrated against laboratory freezing tests. A series of numerical analyses were performed to investigate the effects of soil properties and screw pile shaft configuration on the ground freezing process in field application. The duration required for freezing the soil at a radial distance of 450 mm to −2 °C was estimated and compared. The results showed that the proposed method was applicable in the field. Numerical results showed that the power of removing the heat from the soil was larger when using the screw segment than the smooth segment. The results are expected to guide the field application of artificial ground freezing around screw piles installed in permafrost.

LoRa Technology in Flying Ad Hoc Networks: A Survey of Challenges and Open Issues.

The Internet of Things (IoT) and Flying Ad Hoc Networks (FANETs) have become hot topics among researchers because of the increased availability of Unmanned Aerial Vehicles (UAVs) and the electronic components required to control and connect them (e.g., microcontrollers, single board computers, and radios). LoRa is a wireless technology, intended for the IoT, that requires low power and provides long-range communications, which can be useful for ground and aerial applications. This paper explores the role that LoRa plays in FANET design by presenting a technical overview of both, and by performing a systematic literature review based on a breakdown of the communications, mobility and energy topics involved in a FANET implementation. Furthermore, open issues in protocol design are discussed, as well as other challenges associated with the use of LoRa in the deployment of FANETs.

Study on the storage, processing and preparation of lunar samples returned by the Chang&amp;rsquo;E-5 mission

<p indent="0mm">The Chang’E-5 mission realized China’s first automatic lunar surface sampling return. The Ground Research and Application System is responsible for storing, preparing, and processing the returned lunar samples. The constructed Lunar Sample Laboratory has storage, processing, and preparation functions for the original lunar samples and is capable of long-term sample storage and processing in an environment of high-purity nitrogen on Earth. The Chang’E-5 mission returned two types of samples: scooped and drilled samples. This study developed detailed storage, preparation, and processing protocols for different types of samples. Three working stages will be carried out after the sample is returned to the Lunar Sample Laboratory, including sample processing, storage, and preparation. The detailed procedure involves unsealing the sealed packaging device, separating the scooped and drilled samples, storing the drilled and scooped samples, and preparing the samples. The primary sealed containers for scooped and drilled samples were successfully extracted via a designed unsealing process. Samples for permanent storage, backup storage, engineering display, and scientific research were obtained using the division method for scooped and drilled samples. The samples are stored in different equipments at different locations according to the designed storage method in this study. Scientific samples and some display samples were polished into sections according to the designed preparation method to ensure that the basic sample information can be obtained without destroying the original characteristics of the samples. The prepared samples will be used to analyze their physical and chemical properties and describe their basic characteristics, which can provide important information and technical support for subsequent scientific research.

A dynamic normalized difference index for estimating soil organic matter concentration using visible and near-infrared spectroscopy

Accurate, rapid, and non-destructive estimation of soil organic matter (SOM) is crucial for soil fertility diagnosis and precision farming. Due to the complicated and unstable spectral characteristics of SOM, few SOM spectral indexes have been proposed and widely used. In this paper, a new dynamic normalized difference index (DNDI) was proposed and constructed to estimate SOM using visible and near-infrared spectroscopy. A dynamic correction factor α was used to adjust the optimal wavelength range to obtain more robust features of SOM. Different spectral pre-processing methods were applied and compared. The support vector machine (SVM) model and Partial least square regression (PLSR) model were calibrated based on DNDI and applied to estimate SOM. To this end, a total of 111 soil samples were collected in the southern coastal plain of Laizhou Bay. The results showed that the DNDI index constructed by wavelength optimization could have a higher correlation with SOM than the two-dimensional normalized difference index (NDI). DNDI had the maximum correlation of 0.88 from the first derivative of reflectance, and the NDI correlations were most improved by standard normal variate transform (SNV), with the maximum correlation reaching 0.81. For SOM estimation models, DNDI exhibited better model performance, yielding a validation R2, RMSE, and RPD of 0.78, 0.17 g·kg−1, and 2.01, respectively. Our algorithm has strong application potential for estimating other soil properties and enhancing the application of ground- and satellite-based sensing.