Rotational Phase Research Articles

Effect of leading-edge curvature on the aerodynamics of insect wings

The aerodynamic performance of an insect wing is largely dependent on the leading-edge vortex (LEV) on the wing formed during the rotational translation phase of its flapping motion. The geometry of the wing can directly influence the formation and strength of the LEV. The wing geometry is broadly defined by the aspect ratio and the radii of the wing’s moment of inertia, which can be optimised to obtain the highest possible lift at a given Reynolds number. However, the shape of the leading edge can also affect the LEV and the tip vortex structure. A straight leading edge and a sharp wingtip can affect the spanwise vorticity flux responsible for a stable LEV, thereby affecting the lift and drag. To investigate this in the current study, the wing shape is initially approximated by the Beta function with a straight leading edge and is varied systematically by increasing the leading-edge curvature. The lift and power economy are observed to be enhanced with the leading-edge curvature. The reasons behind the lift enhancement are further investigated by analysing the LEV structures over the wings of various leading-edge curvatures. The curved leading edge is observed to enhance lift at both low as well as high Reynolds numbers relevant to insects.

MEANS, STANDS AND MACHINES FOR TESTING GEAR WHEELS AND GEAR TRAINS OF HELICOPTER REDUCTION TRAINS

The production and repair of such high-tech and important products as helicopters‟ reduction trains is impossible without comprehensive testing of these products, starting with the manufacture of their individual parts and assemblies and ending with the delivery of reduction trains to the customer.
 Various means for testing of gear wheels‟ rims and gear trains of helicopter‟s reduction trains, which have found application in testing equipment, are presented. Devices, testers, stands and machines for various tests are considered in order to control the characteristics of gear trains of aviation reduction trains after certain periods of their operation and repair, aimed at achieving better performance during further operation.
 The considered traditional metrological means of control of gear rims, gear measuring machines and complexes, some stands and machines for testing of reduction trains, pulse controllers and roll machines give an idea of various methods and means of control of gear wheels and gear trains of helicopters‟ reduction trains.
 The main method of experimental research of gear trains of reducers is stand tests both on movable gear wheels and on roll machines.
 Until recently, the most common method for monitoring and diagnosing gear trains has been vibrography, however, existing techniques do not give an accurate picture of the train condition, especially the contact surface of the teeth. During the operation of the gear train as a part of the helicopter‟s reduction train, signals from other sources (rotors, blades, shafts, bearings) are superimposed on the vibration signal generated by the gear train which significantly complicates the extraction and processing of the desired vibration signal.
 One of the most effective methods for monitoring and diagnosing the technical condition of kinematic chains of different complexity, which includes gear trains of helicopters„ reducers is kinematometry. The disadvantage of traditional kinematometry is the need to use high-precision sensors for the frequency and phase of the rotor rotation.
 Control of vibration from the early 1990s to the present time is the most advanced control, the means and methods of which are well developed in the aviation industry.

Cortisol Levels in Infants with Central Coordination Disorders during Vojta Therapy.

Background: Due to the decrease in the percentage of perinatal mortality, which is one of the Millennium Development Goals, the number of children with a central coordination disorder (CCD) has increased, present in up to 40% of premature babies. Neurodevelopmental disorders detected in the diagnostic process require early interventions that will eliminate or overcome existing dysfunctions. These treatments often cause discomfort in the infant, which induces insecurity and activation of basic defense mechanisms. The aim of the work is to assess changes in cortisol concentration in infants treated with the Vojta method. Methods and findings: The study included 35 children with CCD aged between three and nine months. The participants had no comorbidities that could have affected the obtained results. The activities were planned to occur in three stages: 1. Collection of a saliva sample directly before the physiotherapy appointment. 2. Collection of saliva immediately after rehabilitation. 3. Collection of saliva 20 min after the end of rehabilitation. The physiotherapeutic intervention included the assessment of seven reactions of the body position in space according to Vojta and the conduct of a therapeutic session consisting of the first phase of rotation and creeping reflex according to Vojta. The concentration of free cortisol in saliva was assessed with LC-MS/MS. In the first measurement, none of the children presented an excess of the normative concentration of cortisol. The cortisol measurement performed directly after rehabilitation showed above-normative values in three children. In the third measurement, all of the children presented a decreased concentration of free cortisol. The analysis (paired two-tailed t-test, p < 0.05) showed statistically significant differences between particular stages of the measurements. The analysis of the scores obtained in the second measurement showed the concentration of scores in the area of “normal” at a level of 0.83 (normal concentration) and the area “above normal” at the level of 0.005 (very weak concentration). Based on the analysis of significance of the obtained scores, it was found that the result was not accidental, and the Vojta method used in the treatment of children with CCD was suitable. Conclusions: Here, for the first time, we presented how Vojta therapy was correlated with cortisol levels among children with a central coordination disorder.

Microbial Signatures in Fertile Soils Under Long-Term N Management

Long-term reliance on inorganic N to maintain and increase crop yields in overly simplified cropping systems in the U.S. Midwest region has led to soil acidification, potentially damaging biological N2 fixation and accelerating potential nitrification activities. Building on this published work, rRNA gene-based analysis via Illumina technology with QIIME 2.0 processing was used to characterize the changes in microbial communities associated with such responses. Amplicon sequence variants (ASVs) for each archaeal, bacterial, and fungal taxa were classified using the Ribosomal Database Project (RDP). Our goal was to identify bioindicators from microbes responsive to crop rotation and N fertilization rates following 34–35 years since the initiation of experiments. Research plots were established in 1981 with treatments of rotation [continuous corn (Zea mays L.) (CCC) and both the corn (Cs) and soybean (Glycine max L. Merr.) (Sc) phases of a corn-soybean rotation], and of N fertilization rates (0, 202, and 269 kg N/ha) arranged as a split-plot in a randomized complete block design with three replications. We identified a set of three archaea, and six fungal genera responding mainly to rotation; a set of three bacteria genera whose abundances were linked to N rates; and a set with the highest number of indicator genera from both bacteria (22) and fungal (12) taxa responded to N fertilizer additions only within the CCC system. Indicators associated with the N cycle were identified from each archaeal, bacterial, and fungal taxon, with a dominance of denitrifier- over nitrifier- groups. These were represented by a nitrifier archaeon Nitrososphaera, and Woesearchaeota AR15, an anaerobic denitrifier. These archaea were identified as part of the signature for CCC environments, decreasing in abundance with rotated management. The opposite response was recorded for the fungus Plectosphaerella, a potential N2O producer, less abundant under continuous corn. N fertilization in CCC or CS systems decreased the abundance of the bacteria genera Variovorax and Steroidobacter, whereas Gp22 and Nitrosospira only showed this response under CCC. In this latter system, N fertilization resulted in increased abundances of the bacterial denitrifiers Gp1, Denitratisoma, Dokdonella, and Thermomonas, along with the fungus Hypocrea, a known N2O producer. The identified signatures could help future monitoring and comparison across cropping systems as we move toward more sustainable management practices. At the same time, this is needed primary information to understand the potential for managing the soil community composition to reduce nutrient losses to the environment.

Dzhanibekov effect in a physics classroom

The purpose of this publication is to present a novel approach to the demonstration of the Dzhanibekov effect. The main idea of our version is to use a lightweight spinning top of a spherical external form but distinct principal moments of inertia floating in the upward flow of air. As a result, the Dzhanibekov effect can be easily demonstrated anywhere on Earth: in any classroom, or even in the ‘home-lab’. The proposed demonstration allows one to observe the periodical flipping motion of the asymmetrical top with the clearly seen quasi-stable rotational phase. It may also become the base for various theoretical and experimental research projects for students.

Characterisation of the main belt asteroid (223) Rosa

Context. The ESA JUICE space mission, on its way to study Jupiter’s environment and icy moons, will pass twice through the main asteroid belt. For this reason, the possibility to perform an asteroid flyby has been investigated. Aims. We aim to gain insight into the physical properties of the outer main belt asteroid (223) Rosa, which has been proposed as a potential JUICE flyby target. Methods. We report new visible and near-infrared spectroscopic observations at different rotation phases. Additionally, we perform a literature review of all the available physical properties, such as diameter, albedo, mass, and rotational period. Results. We find that asteroid Rosa is an X-type asteroid that shows no significant spectral variability combining the new and literature spectroscopic data. Its large size and orbital semimajor axis in the outer main belt indicate that Rosa does not belong to the Themis family, while its albedo is only marginally compatible with the family. Rosa’s estimated density is in agreement with those of other low-albedo X-type asteroids. Hence, we propose that Rosa is a planetesimal that accreted in the protoplanetary disk beyond the snow line.

Dual-Band Circularly Polarized Antenna With Two Pairs of Crossed-Dipoles for RFID Reader

In this article, a low-profile high-efficiency dual-band 0.915/2.45 GHz circularly polarized (CP) antenna and its array are designed for radio frequency identification (RFID) reader applications. First, a dual-band antenna element is introduced to achieve dual-sense CP radiation using two pairs of crossed-dipoles for the first time. The right-hand CP (RHCP) wave at lower band is mainly produced by the first-order mode on longer dipole, while the left-hand CP (LHCP) wave at upper band is generated by the combination of first-order mode on shorter dipole and third-order mode on longer dipole. An artificial magnetic conductor (AMC) is used to improve the antenna directivity with low profile and makes this antenna easy to integrate into RFID system. Then, a rotated sequential phase feed CP array is proposed, fabricated, and measured. Measured impedance bandwidth (IBW) for <inline-formula> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert &lt; -10$ </tex-math></inline-formula> dB is more than 40.0&#x0025; at these two bands. Measured 3 dB axial ratio bandwidths (ARBWs) are 32.0&#x0025; (0.77&#x2013;1.06 GHz) and 27.8&#x0025; (2.22&#x2013;2.95 GHz). Compared with other dual-band CP reader antennas, which work in 0.915/2.45 GHz RFID systems, this new antenna array has a simpler configuration to achieve dual-band CP radiation. In addition, the 3 dB ARBWs are much wider than the previous antennas. Moreover, because the feeding network of this array is quite simple, the radiation efficiency is very high (&#x003E;90&#x0025;), and the peak gains are more than 9.0 and 15.0 dBic at corresponding bands.

The Distribution of Oxygen, Calcium, and Strontium Over the Surface of 21 Com

Abstract Comparison of optical high resolution high signal-to-noise ELODIE spectra of 21 Com taken in 2004 April and separated by about half of the 2 days rotational period, reveals variations of the oxygen, calcium and strontium lines between rotational phases 0.94 and 0.48. Whereas the lines of oxygen and calcium are stronger at phase 0.94, those of strontium strengthen at phase 0.48. The synthesis of strong Sr ii lines yields disk-averaged estimates of the abundances of strontium: about 200 times solar at phase 0.94 and 450 solar at phase 0.48 for strontium. However the O i and Ca ii lines are too blended to derive unambiguous quantitative information on the abundance and distribution of oxygen and calcium over the surface of 21 Com. The likely underabundance of oxygen might be quantified using stronger far-ultraviolet transitions.

Rheological properties of rotator and crystalline phases of alkanes

Linear long-chain organic molecules are known to form lamellar intermediate phases (called also rotator phases) between their fully ordered crystalline phases and their isotropic liquid phases. The temperature range of occurrence and the properties of these intermediate rotator phases are crucially important for the texture of many food and cosmetic products, for the flow of various phase-change materials used in energy storage and transport, and for several processes in living nature, such as the formation of superhydrophobic and self-healing cuticle layers in plants and insects. Nevertheless, data for the rheological properties of such peculiar materials below their melting point, Tm, are almost missing, due to the specific difficulties in the respective rheological measurements. In the current study we describe a methodology for measuring and comparing the shear rheological properties of rotator (R) and crystalline (C) phases formed in bulk hydrocarbons at temperatures below Tm. We apply this approach to characterize the rheological properties of R and C phases formed upon cooling of alkanes with chain length varied between 17 and 30 carbon atoms. For comparison, we study also several alkane mixtures and one alkene with double bond at the end of its chain. The obtained results show that the storage and loss moduli of the rotator phases are ca. 10-times lower than those of the respective crystalline phases. We found also that the rheological properties of the crystal phases depend mainly on the subcooling temperature below the crystallization temperature, TC, while the R phases become softer with the increase of the molecular length. We explain these results by assuming that the rheological properties of the crystal phases are determined mainly by the sliding of the ordered crystal domains with respect to each other, while in the rotator phases we have multiple defects in the molecular packing which increase with the alkane length. The proposed methodology and the obtained results serve as a solid basis for further rheological studies of this important class of technological systems.

The Distribution of Silicon and Magnesium over the Surface of 21 Com

Abstract Inspection of 10 individual spectra taken over the 24 hr monitoring of 21 Com with International Ultraviolet Explorer on 1991 April 17 reveals variations of low excitation lines of Si ii between rotational phases ϕ = 0.18 and ϕ = 0.65 of the 2 days period, suggesting a inhomogeneous repartition of silicon over the surface of 21 Com. The silicon lines are weaker at rotational phase ϕ = 0.18. More recent optical high resolution high signal-to-noise ELODIE spectra taken in 2004 April confirm the variations of silicon lines from phase ϕ = 0.99 to ϕ = 0.47. The synthesis of the optical Si ii lines yields estimates of the abundances of silicon: 8 times solar at phase 0.99 and 10 times solar at phase 0.47. The large FUV variations of 21 Com appear then to be partly due to changes in the silicon line and continuous opacity as the star rotates. In contrast, the Mg ii lines do not show convincing variations between the two rotational phases observed in the optical.

Dynamic characteristics of a simply supported elastic beam with three induction motors

In the paper, the dynamic characteristics of a three induction motor driven system on a simply supported elastic beam are studied. Firstly, a dynamic coupling model of the whole system is established according to the Hamilton principle and discretized by applying the assumed mode method. Next, the synchronization solutions containing the average rotation speeds and phase differences of three motors and their stability are calculated and analyzed by using the average perturbation method. As a result, the synchronization and stability conditions of self-synchronization of three motors are established. Finally, the feasibility of the average perturbation method is verified by comparing the theoretical results with the simulation results. The results indicate that the elastic support has a large influence on the motion states of three motors. There is the self-synchronization phenomenon of three motors on the elastic beam. There appear the Sommerfeld effect (rotational speed capture and jump phenomena) near the resonance of the beam and the synchronous states of three motors will rapidly change before and after the resonance of beam. The large changes of the motion states of three motors cause the impacts of the responses of the elastic beam structure. Additionally, the effects of the structure parameters such as unbalance mass, power frequency, beam size and vibration modes on the dynamic characteristics of the system are discussed. This paper can provide some references for the design of multi-motor systems on the elastic foundations.

The influence of conformational defects on the development of structural phase transition in tetracosane C24H50

The kinetics of the first-order solid-state structural transition in monodisperse n-alkanes samples of even tetracosane C24H50 was studied by FTIR spectroscopy. The existence of many irregular conformers in solid phases of tetracosane, the concentration of which reaches a maximum when approaching the melting temperature, has been demonstrated. The existence of these defective molecules promotes transitions between different rotator phases in the solid state.

Visualization of hydrodynamic and physico-chemical processes in rotating and vibrating containers

Variable inertial fields are an efficient way to control the behaviour of hydrodynamic systems. Forces of inertia can be used, for example, to stabilize or destabilize systems with an interface or density gradient, to mix multiphase or non-isothermal fluids. The implementation of this approach means that liquids fill the periodically moving containers. In this paper, the situations are considered when the containers perform either rotation or translational vibrations. Methods for measuring the density and velocity fields of convective flows in reacting hydrodynamic systems are described. Interferometry is used to visualize the density distribution. Particle image velocimetry (PIV) is used to study the structure and velocity of the flows. Optical instruments are installed stationary in the laboratory system. For video recording, a camera shutter is synchronized with the motion of a container, and thus the images are captured in a fixed phase of oscillations or rotation. Constructions of the containers make it possible to illuminate the working volume through transparent walls at different angles or in different planes. They also provide a compensation for the centrifugal pressure and allow interference cells to be used in overload conditions. The successful application of the methods in experimental studies of chemo-hydrodynamic processes is demonstrated.

Evaluation of short-term temporal evolution of Pluto’s surface composition from 2014–2017 with APO/TripleSpec

In this work we present the results of a spectral observing campaign of Pluto to search for temporal changes in surface composition on 1- to 3-year timescales. Near-infrared spectra of Pluto were obtained from June 2014 to August 2017 with the TripleSpec cross-dispersed spectrograph at the Apache Point Observatory’s 3.5-meter Astrophysical Research Consortium (ARC) telescope. Observations were requested in order to obtain spectra of approximately the same sub-observer hemisphere ∼14 months apart, thus removing the effects of viewing geometry and rotation phase. Comparison of the CH4 (methane) band areas and band center shifts between each component of these “matched pairs” revealed a surface in transition. Band areas for the 1.66 and 1.72μm CH4 absorption features exhibited a >5-σ increase between 2014-06-17 and 2015-08-19, corresponding to a sub-observer hemisphere centered at ∼280°E, with the latter date only 1 month after the New Horizons flyby of Pluto. The majority of matched pairs were obtained of the anti-Charon hemisphere, home to the bright, volatile-rich Sputnik Planitia, and did not present statistically significant changes in CH4 band areas. CH4 band center shifts, which provide information on the mixing state of CH4 and N2 in solid solution, were calculated between components of each matched pair, with no significant band shifts detected. The favored explanation for these combined results is the sublimation of more-volatile N2 from the northern latitudes of Pluto in the lead-up to northern hemisphere summer solstice in 2029, leading to an increase in CH4 concentration.

Magnetic-free silicon nitride integrated optical isolator

Integrated photonics enables signal synthesis, modulation and conversion using photonic integrated circuits (PICs). Many materials have been developed, among which silicon nitride (Si3N4) has emerged as a leading platform particularly for nonlinear photonics. Low-loss Si3N4 PICs have been widely used for frequency comb generation, narrow-linewidth lasers, microwave photonics and photonic computing networks. Yet, among all demonstrated functionalities for Si3N4 integrated photonics, optical non-reciprocal devices such as isolators and circulators have not been achieved. Conventionally, they are realized based on the Faraday effect of magneto-optic materials under an external magnetic field; however, it has been challenging to integrate magneto-optic materials that are not compatible with complementary metal–oxide–semiconductors and that require bulky external magnet. Here we demonstrate a magnetic-free optical isolator based on aluminium nitride (AlN) piezoelectric modulators monolithically integrated on low-loss Si3N4 PICs. The transmission reciprocity is broken by spatio-temporal modulation of a Si3N4 microring resonator with three AlN bulk acoustic wave resonators that are driven with a rotational phase. This design creates an effective rotating acoustic wave that allows indirect interband transition in only one direction among a pair of strongly coupled optical modes. A maximum of 10 dB isolation is achieved under 300 mW total radiofrequency power applied to three actuators, with minimum insertion loss of 0.1 dB. An isolation bandwidth of 700 MHz is obtained, determined by the optical resonance linewidth. The isolation remains constant over nearly 30 dB dynamic range of optical input power, showing excellent optical linearity. Our integrated, linear, magnetic-free, electrically driven optical isolator could be a key building block for integrated lasers and optical interfaces for superconducting circuits. An electrically driven, magnetic-free optical isolator is demonstrated. The device, based on aluminium nitride piezoelectric modulators and a silicon nitride microring resonator, may be useful for integrated lasers and other opto-electric systems.

Wood-based boards mechanical properties and their effects on the cutting process during shredding

In order to design effective shredding machines dedicated to shredding wood-based waste, information about the mechanical properties of materials subjected to shredding is necessary. A number of mechanical properties of particleboard, oriented strand boards, and medium-density fibreboards in the aspect of shredding process have been experimentally determined in the article. The influence of material type, blade geometries, and cutting depth on cutting force and elasticity coefficient were analysed. Blade geometries reflect different phases of rotation of the cylindrical wood chipper’s knife. It has been shown that a knife with the most favourable geometry is characterized by the lowest values of the stiffness coefficient for each of the materials. This is the geometry of the cylindrical wood chipper’s knife exactly halfway into the cutting process. By contrast, the least favourable geometry is characterized by a knife corresponding to the beginning of the cutting process. Among the tested materials, the medium density board requires the most energy to change its structure, and the laminated particleboard requires the least. The presented results can be a set of input data necessary to model the work required to implement the cutting process, but also enable validation of existing cutting models.

The Mean Underabundances of Carbon and Aluminum Over the Surface of 21 Com from Its Far-ultraviolet Spectra Recorded by IUE

Abstract The comparison of a coadded International Ultraviolet Explorer (IUE) far-ultraviolet spectrum of 21 Com (A3p SrCr) to that of the standard star α Psa (A3V) reveals large differences in the resonance and low-excitation lines of C i and Al ii. All the lines of these species are significantly weaker in the mean spectrum of 21 Com. The synthesis of these lines consistently yields sizable underabundances for 21 Com of about 0.5 times the solar carbon, and 0.20 times solar for aluminum. Inspection of 10 individual spectra taken over the 24 hr monitoring of 21 Com with IUE on 1991 April 17 does not reveal convincing variations of the lines analyzed here between rotational phases 0.18 and 0.65 of the 2 days period, suggesting a uniform repartition of these 2 elements over the hemisphere of 21 Com observed then.

The Thousand-Pulsar-Array programme on MeerKAT – VI. Pulse widths of a large and diverse sample of radio pulsars

Abstract We present pulse width measurements for a sample of radio pulsars observed with the MeerKAT telescope as part of the Thousand-Pulsar-Array (TPA) programme in the MeerTime project. For a centre frequency of 1284 MHz, we obtain 762 W10 measurements across the total bandwidth of 775 MHz, where W10 is the width at the 10 per cent level of the pulse peak. We also measure about 400 W10 values in each of the four or eight frequency sub-bands. Assuming, the width is a function of the rotation period P, this relationship can be described with a power law with power law index μ = −0.29 ± 0.03. However, using orthogonal distance regression, we determine a steeper power law with μ = −0.63 ± 0.06. A density plot of the period-width data reveals such a fit to align well with the contours of highest density. Building on a previous population synthesis model, we obtain population-based estimates of the obliquity of the magnetic axis with respect to the rotation axis for our pulsars. Investigating the width changes over frequency, we unambiguously identify a group of pulsars that have width broadening at higher frequencies. The measured width changes show a monotonic behaviour with frequency for the whole TPA pulsar population, whether the pulses are becoming narrower or broader with increasing frequency. We exclude a sensitivity bias, scattering and noticeable differences in the pulse component numbers as explanations for these width changes, and attempt an explanation using a qualitative model of five contributing Gaussian pulse components with flux density spectra that depend on their rotational phase.

EvryFlare. iv. Detection of Periodicity in Flare Occurrence from Cool Stars with TESS

Abstract Phased flaring, or the periodic occurrence of stellar flares, may probe electromagnetic star−planet interaction (SPI), binary interaction, or magnetic conditions in spots. For the first time, we explore flare periodograms for a large sample of flare stars to identify periodicity due to magnetic interactions with orbiting companions, magnetic reservoirs, or rotational phase. Previous large surveys have explored periodicity at the stellar rotation period, but we do not assume periods must correspond with rotation in this work. Two-minute TESS light curves of 284 cool stars are searched for periods of 1–10 days using two newly developed periodograms. Because flares are discrete events in noisy and incomplete data, typical periodograms are not well suited to detect phased flaring. We construct and test a new Bayesian likelihood periodogram and a modified Lomb–Scargle periodogram. We find six candidates with a false-alarm probability below 1%. Three targets are ≥3σ detections of flare periodicity; the others are plausible candidates that cannot be individually confirmed. Periods range from 1.35 to 6.7 days and some, but not all, correlate with the stellar rotation period or its 1/2 alias. Periodicity from two targets may persist from TESS Cycle 1 into Cycle 3. The periodicity does not appear to persist for the others. Long-term changes in periodicity may result from the spot evolution observed from each candidate, which suggests magnetic conditions play an important role in sustaining periodicity.

Response of soil organic matter to cover cropping in water-limited environments

Cover crops are promoted to improve soil health and soil carbon (C) sequestration in agroecosystems, yet responses of various soil organic carbon (SOC) and nitrogen (N) components to cover cropping have not been quantified for water-limited environments. This study evaluated the response of SOC and N components to different cover crops and mixtures in limited irrigation winter wheat (Triticum aestivum L.)-sorghum (Sorghum bicolor L. Moench)-fallow rotation. Cover cropping treatments included pea (Pisum sativum L.), oats (Avena sativa L.), and canola (Brassica napus L.); mixtures of pea + oats (POmix), pea + canola (PCmix), pea + oats + canola (POCmix), and a six-species mixture (SSmix) of pea + oats + canola + hairy vetch (Vicia villosa Roth) + forage radish (Raphanus sativus L.) + barley (Hordeum vulgare L.); and a fallow. Cover crop treatments were arranged in a randomized complete block design within each phase of the crop rotation. Soil samples were collected in the summer of 2019 and 2020 from the 0–15 cm depth of study plots established in fall 2015 and analyzed for various soil organic matter (SOM) components. Soil inorganic N was 7–36% lower with cover crops than fallow. The PCmix had 48–73% greater 24-h-carbon dioxide-carbon (CO2-C) than fallow, canola, and SSmix at termination time. Thirty-six days after termination, particulate organic carbon (OC) content was 61–69% higher with pea, SSmix, and POCmix than fallow. The SOC content was 9.3–22% greater with oats than pea, canola, POmix, and SSmix. Similarly, total N content with oats was 10% and 22% higher than with SSmix and canola, respectively. The increase in SOC and total N were primarily observed in intermediate-size aggregates (250 μm–2 mm and 53–250 μm). However, the minimum data set of soil health included SOC, soil pH, labile organic nitrogen (LON), mineral-associated organic nitrogen (MAON), and microbial biomass carbon (MBC). While this study showed a diverse response of SOC and N components to various cover crop treatments, oats and their mixture as cover crops had greater SOC and total N than other cover crops. Cover cropping could improve soil health in crop-fallow rotations in water-limited environments.