Hard Spring Research Articles

Nonlinear interactions of an n-layer X-shape low-frequency vibration isolator equipped with a nonlinear vibration absorber at 1:1 internal resonance: analytical and numerical investigations

This work addresses, for the first time, the nonlinear dynamics of an n− layers bioinspired X− shape low-frequency vibration isolation system equipped with a nonlinear vibration absorber. The comprehensive mathematical model governing the two-degree-of-freedom system has been derived using Lagrangian mechanics. The method of averaging was applied to obtain an accurate analytical solution for the derived mathematical model. Utilizing the established analytical solution, the dynamical characteristics of the X− shape vibration isolator have been explored both as a single-degree-of-freedom system and after coupling with the proposed vibration absorber, as a two-degree-of-freedom system. The influence of different system parameters, including the number of structure layers, the initial inclination angle, the X− shape rod length, and the absorber stiffness and damping coefficients, on the vibration isolation performance has been investigated. The main findings indicate that while the single-degree-of-freedom X− shape low-frequency vibration isolator performs well in eliminating low-frequency vibration excitations, it exhibits strong vibration levels when the base excitation frequency exceeds the structure's natural frequency. Additionally, it was found that coupling a highly damped linear vibration absorber to the X− shape isolator not only eliminates the strong oscillations of the structure when subjected to high-frequency base excitations but also enhances the structure's low-frequency vibration isolation performance. Moreover, it was reported that integrating a nonlinear vibration absorber with either soft or hard spring characteristics instead of a linear one may degrade the vibration isolation performance of the structure rather than enhance it. Finally, numerical validation of all the analytical results was performed, which showed excellent correspondence with the analytical findings.

Time-delay feedback control of nonlinear forced vibration of graphene/piezoelectric sandwich nanoplates under a mechanical shock

In this study, the nonlinear forced vibration of graphene/piezoelectric sandwich nanosheets under mechanical impact was investigated. For the first time, linear (displacement and velocity) and nonlinear (displacement) time-delay proportional derivative (PD) controllers were applied to graphene/piezoelectric sandwich nanosheets, and the primary/secondary resonance under different time-delay parameters were analyzed. An approximate analytical solution for the nonlinear forced vibration control equation was obtained using the multiple scale perturbation method, and the stability of graphene/piezoelectric sandwich nanosheets under primary/secondary resonance conditions was discussed using the Ross Herwitz theorem. Finally, the results of this study were compared with those of other studies. The feasibility of the research methodology was demonstrated. On this basis, the research results indicate that linear displacement delay, nonlinear displacement delay, and velocity delay parameters can suppress the unsteady vibration characteristics of the main system. And comparing the linear and nonlinear displacement time-delay, it is found that the nonlinear displacement time-delay has a greater effect on the system. Specifically, the presence of nonlinear displacement time-delay changes the vibration characteristics of the curve from hard spring characteristics to soft spring characteristics. Comparison of displacement time-delay and velocity time-delay reveals that velocity time-delay gives better control over the system. In addition, the results show that the excitation amplitude, nonlocal parameters, and external voltage enhance the nonlinear characteristics of the system under the main and superharmonic resonance conditions before the time-delay control. Subharmonic resonance conditions, the system parameters make the vibration range wider. After the time-delay control, the influence of these three factors on the system vibration is significantly reduced for the three resonance conditions, especially for the non-local parameters. The results of the study can provide guidance for active control of time delay in different types of nanodevices for engineering applications.

СЕЛЕКЦИОННЫЕ КРИТЕРИИ ЗАСУХОУСТОЙЧИВОСТИ ТВЕРДОЙ ЯРОВОЙ ПШЕНИЦЫ В УСЛОВИЯХ ЗАПАДНОЙ СИБИРИ

The aim of research is to conduct a comparative assessment of varieties of durum spring wheat for drought resistance in the conditions of Western Siberia. The experiments were laid out after fallow in the conditions of the southern forest-steppe at the stationary site of the laboratory of selection of durum wheat of the Federal State Budgetary Scientific Institution Omsk Scientific Center. In long-term studies (2001–2018) on a large set of varieties (26), when studying the yield, the number of grains in an ear, the weight of 1000 grains, the parameters of drought resistance were determined. In this case, the following indicators for these traits were calculated: average over the years of research, average in dry years, average in favorable years, the degree of reduction under stress compared to conditions without stress, the drought resistance index (DSI according to R.A. Fischer, R. Maurer). Tests on the studied characteristics revealed the following varieties: by yield – Omskiy Izumrud, Aleyskaya, Omskaya Stepnaya, Zhemchuzhina Sibiri, by weight of 1000 grains – Bezenchukskaya Stepnaya, Omskaya Stepnaya, Aleyskaya, Elizavetinskaya, Svetlana, by the number of grains in an ear – Omskiy Izumrud, Saratovskaya Zolotistaya, Zhemchuzhina Sibiri, Omskaya Stepnaya, Bezenchukskaya Stepnaya. According to the general integrated assessment, the best indicators were obtained for the varieties Omskaya Stepnaya, Omskiy Izumrud, Bezenchukskaya Stepnaya, Aleyskaya, Zhemchuzhina Sibiri, Saratovskaya Zolotistaya. The indicators of average values under drought, the degree of reduction under stress conditions, the drought resistance index for grain yield, 1000-grain weight, and the number of grains in an ear are reliable criteria for drought resistance of hard spring wheat. The best differentiating ability is possessed by tests calculated by yield and the number of grains in an ear.

Different scenarios in sloshing flows near the critical filling depth

In the present paper, the sloshing flow in a cuboid tank forced to oscillate horizontally is investigated with both experimental and numerical approaches. The filling depth chosen is $h/L=0.35$ (with h the water depth and L the tank height), which is close to the critical depth. According to Tadjbakhsh & Keller (J. Fluid Mech., vol. 8, issue 3, 1960, pp. 442–451), as the depth passes through this critical value the response of the resonant sloshing dynamics changes from ‘hard spring’ to ‘soft spring’. The experimental tank has a thickness of $0.1L$ , reducing three-dimensional effects. High-resolution digital camera and capacitance wave probes are used for time recording of the surface elevation. By varying the oscillation period and the amplitude of the motion imposed on the tank, different scenarios are identified in terms of free-surface evolution. Periodic and quasi-periodic regimes are found in most of the frequencies analysed but, among these, sub-harmonic regimes are also identified. Chaotic energetic regimes are found with motions of greater amplitude. Typical tools of dynamical systems, such as Fourier spectra and phase maps, are used for the regime identification, while the Hilbert–Huang transform is used for further insight into doubling-frequency and tripling-period bifurcations. For the numerical investigation, an advanced and well-established smoothed particle hydrodynamics method is used to aid the understanding of the physical phenomena involved and to extend the range of frequencies investigated experimentally.

Dynamic Analysis of a Double-Cable-Stayed Shallow Arch Model Under Multi-Frequency Excitation by IHB Method

To reveal the dynamic properties of cable-stayed bridges under complex external excitations, a double-cable-stayed shallow arch model induced by multi-frequency harmonic excitations is established. The cable and shallow arch exhibit primary or subharmonic resonances by sweeping excitations simultaneously and asynchronously. Galerkin method, one/two time scales Incremental Harmonic Balance (IHB) method, and Runge–Kutta (RK) method are applied to explore the nonlinear dynamic responses. Research results demonstrate that both the cables and shallow arch present soft and hard spring properties, despite the very weak hard spring of the shallow arch; one-way dynamic interaction among the cables and the shallow arch is discovered when sweeping excitations asynchronously.

The influence of individual elements of agricultural technology on the productivity of durum wheat in the southern forest-steppe of the Omsk region

Relevance. For the manufacture of high-quality pasta, durum wheat grain is used. Improving the productivity of hard spring wheat is an urgent task. The formation of a powerful root system is the key to the full supply of nutrients and plastic substances to the plant. Increased productivity, the number of spikebearing shoots. Plants become more resistant to adverse environmental factors, which is important for spring durum wheat, which is more demanding than spring soft wheat. The timing of sowing and especially the application of mineral fertilizers are a significant factor affecting not only the formation of individual elements of the crop structure, which subsequently form the productivity of plants, but also the formation of the root system. To do this, it is necessary to choose the optimal sowing time, at which the critical phases of plant development fall under the most favorable agrometeorological conditions and the formation of the most powerful root system.Results. The conducted studies allow us to recommend the most optimal terms of sowing and the use of fertilizers to ensure the efficiency of growing durum spring wheat. In dry conditions, when sowing crops without applying fertilizers, sowing in the second ten days of May is most effective. If it is possible to apply nitrogen fertilizers and nitrogen-phosphorus fertilizers, it is better to sow durum spring wheat in the second and third decades of May.

Productivity of soft and hard spring wheat varieties under the conditions of Primorsky Krai

Relevance. Currently, the most important tasks of breeding are the creation and introduction into production of new high—yielding varieties, resistant to stressful environmental conditions and with high grain quality, adapted to the conditions of the monsoon climate.The purpose of the study is to study varieties of spring soft and durum wheat of various origins according to the main economically valuable characteristics in the conditions of the Primorsky Territory.Methods. The research was conducted at FSBSI «FSC of Agricultural Biotechnology of the Far East named after A.K. Chaiki» in 2020–2022. Sixteen spring wheat varieties of various breeding origin served as the research object — six soft spring wheat varieties and ten hard spring wheat varieties. The weather conditions during the growing season of wheat differed over the years of the research (2020–2022). This allowed an objective evaluation of the breeding material for adaptability and resistance to stress factors.Results. For breeding and production, wheat varieties with high yields (more than 4.0 t/ha) have been identified: spring soft — Voronezh 18, Rima, Primorskaya 50, spring hard — Don Elegia. As a result of the correlation analysis, high positive associations were revealed between yield and productive bushiness (r = 0.95), the mass of 1000 grains (r = 0.85), the number of spikelets in the ear (r = 0.84). Aleyskaya, Khabarovsk and Primorskaya 40 varieties stood out with the highest index of protein and gluten in grain. Variety Sunny 573 was distinguished by high hardness (67.5%) and grain type (785 g/l).

Release of ‘UI Gold’ hard white spring wheat

Abstract‘UI Gold’ (Reg. no. CV‐1205, PI 700874) hard white spring wheat (Triticum aestivum L.) was developed by the Idaho Agricultural Experiment Station and released in 2022. UI Gold was derived from the cross A03018S‐E × WA8123. It was tested under experimental numbers A11434‐14 and IDO1804S and showed high grain yield and excellent bread‐baking quality when grown in both irrigated and dryland conditions. UI Gold has grain yield comparable to the high‐yielding hard white spring check cultivar ‘Dayn’ and higher yield than the widely grown hard white spring wheat cultivars ‘SY Teton’ and ‘UI Platinum’. UI Gold has gluten strength similar to SY Teton and greater gluten strength than Dayn and UI Platinum. Compared with Dayn, in various trials UI Gold matured 3–4 days later and was 1–5 cm shorter.

Towards stable wheat grain yield and quality under climatic instability

AbstractGlobal wheat production is likely to be affected by projected warming and water scarcity. As climate changes faster than breeding, we focused on genotypic and environmental effects on grain production and quality of present wheat cultivars. To mimic the continuous challenges farmers face given the erratic rainy seasonal and temperature pattern of the Eastern Mediterranean, 15 commercial hard spring wheat (HSW) cultivars were evaluated at Gilat Research Center, Israel, over four seasons constituting 33 independent dryland field environments. Grains of HSW samples from commercial and experimental nurseries across Israel over three seasons were also analyzed to represent the Eastern Mediterranean wheat agroclimatic span. Samples were analyzed for grain yield and quality traits. High humidity and mild temperature during grain filling were associated with higher production, flour extraction, and dough extensibility; whereas high precipitation was mainly associated with lower protein, lower gluten content, and dough tenacity. Correlation between grain protein content and wet gluten was affected by environment and is cultivar dependent, as precipitation during a specific phase plays a major factor for some cultivars, while others are affected more by temperature, humidity, or other factors. Test weight and gluten index showed the clearest relation between performance and variation, enabling to identify cultivar stability across environments. Stable cultivars are more acceptable in the market, however, if a specific quality parameter is highly important for the millers and/or the bakers then the stability of this parameter under multiple growth conditions might serve as a decision support tool for on‐farm commercial cultivar selection.

Research on the Nonlinear Stiffness Characteristics of Double-Row Angular Contact Ball Bearings under Different Working Conditions

To study the variation rules of nonlinear stiffness of double-row angular contact ball bearings (DR-ACBB), this paper proposed a general mathematic model for DR-ACBB under three different configurations based on the improved quasi-static model of ball bearings, an explicit expression stiffness matrix of DR-ACBB is analytically derived, and a double-layer nested iterative algorithm based on the Newton–Raphson method is designed to realize the efficient solution of the proposed model. Then, the effects of the preload, speeds, and loads on the nonlinear stiffness variations of DR-ACBB under different arrangements are comparatively analyzed. The results show that DR-ACBB under the DB and DF configurations have the same variation rule in axial and radial stiffness; that is, a nonlinear soft-spring stiffness characteristic (i.e., the stiffness decreases with the external load) within the low-speed range and light load condition, and a nonlinear hard spring stiffness characteristic (i.e., the stiffness increases with the external load) within the high-speed range or heavy load condition.

Effects of delayed harvest on wheat quality, gluten strength, and protein composition of hard red spring wheat

AbstractBackground and ObjectivesDelayed harvest of spring wheat is a common occurrence in the Northern Great Plains region of North America, especially western Canada, as a result of inclement weather. This can have negative impacts on the yield, grade, and quality of wheat leading to financial loss for farmers and processing complications along the value chain. The objective of this study was to investigate the effects of delayed harvest on wheat quality, gluten strength, and gluten protein composition about which little is known. Four leading varieties of Western Canadian hard red spring bread wheat were grown in replicated trials at four locations, involving four harvest dates from physiological maturity to 6 weeks thereafter.FindingsDelayed harvest had a statistically significant effect on Fusarium damaged kernels (increased), grain test weight (decreased), flour ash (decreased), gluten strength (increased) measured by mixograph development time and work input to peak development, and two protein compositional factors: HMW glutenin in flour protein and ratio of HMW glutenin to soluble prolamins (both increased).ConclusionsConsidering the totality of results, apart from grade and test weight, the effects of delayed harvest on wheat quality on gluten strength, while significant, were relatively minor compared to the much larger effects of growing location and genotype. Expanding the study to include more growing locations and seasons to capture a wider range of weather conditions may be required to reveal more pronounced effects caused by harvest delays. Results emphasize the importance of harvesting wheat as soon as is practical after physiological maturity to limit degradation of grade and economic loss.Significance and NoveltyResults clarify the limited understanding of the effects of delayed harvest on wheat quality and related properties. There appear to be no previous studies specifically evaluating the effects of delayed harvest on gluten strength and protein composition of hard spring wheat, especially considering that the time frame in the present study begins at physiological maturity. Reduced grades and deterioration of grain quality as a result of post‐growing season precipitation and cooler temperatures, and weathering in general, did not result in reduced gluten strength as might be expected when harvest was delayed. The small but significant improvement in gluten strength and highly correlated increase in glutenin per unit protein for the latter two harvest dates appear to be in‐line with postharvest effects of wheat maturation.

ЭКОНОМИЧЕСКОЕ ОБОСНОВАНИЕ ВОЗДЕЛЫВАНИЯ ТВЕРДОЙ ПШЕНИЦЫ В ЗОНЕ ЧЕРНОЗЕМА ЮЖНОГО НИЖНЕ-ВОЛЖСКОГО РЕГИОНА

The experience and economic analysis made it possible to establish new elements of technological methods for increasing the yield of grain crops, which are economically more profitable. It has been economically proven that modern varieties of durum wheat against the background of the use of biofertilizers are more rational than the traditional application of mineral nutrition, the cost of which is several orders of magnitude higher than the cost of biofertilizers. The object of research was zoned varieties of durum wheat, recommended for the 9th region and promising varieties, which were distinguished not only by high plasticity and adaptability to arid conditions, but also had a positive effect on the course of soil microbiological processes. Materials and methods. The field experiment was started in 2018…2022. in the KFH "Eliseev A.N", located in the chernozem zone of the southern Mikhailovsky district of the Volgograd region. The subject of the study was the variety of hard spring wheat Krasnokutka 13 and winter wheat - Aksinit with the processing of seed material with biofertilizers and the application of mineral fertilizers under the given yield levels (2.0 t/ha; 4.0 and 6.0 t/ha). Results and conclusions. A five-year experience has shown that the calculated norms of mineral nutrition are quite competitive with new types of biofertilizers. With less expensive funds for their purchase, they are able to bring the yield up to 2.14 t/ha (variety Krasnokutka 13) on crops of spring durum wheat, and up to 3.84 t/ha on winter durum wheat (variety Aksinit) using Gumi biofertilizer 20. The economic component obtained by calculation indicates that the fundamental indicator of profitability on the control variant of the Krasnokutka 13 variety was 45%, on the corresponding variant of the Aksinit variety - 262%. Seed treatment with Gumi 20 biofertilizer on variety Krasnorkutka 13 led to an increase in profitability up to 167%. Its maximum values were noted in the variety Aksinit on the variant with the treatment with Gumi 20 biofertilizer and amounted to 329%.

Биоудобрения и минеральное питание - основа урожайности твердой пшеницы в зоне чернозема южного Нижнего Поволжья

The experiment made it possible to develop new approaches to technological methods for increasing the yield of spring and winter durum wheat varieties against the background of creating prerequisites for preserving the natural fertility of the soil. Along with the released varieties, promising varieties of wheat were studied against the background of the use of new generation biofertilizers and developed doses of mineral nutrition for the planned yield levels. As, along with durum wheat varieties, which are accepted for zoning in the 8th region, modern varieties with high plasticity and adaptability to arid conditions were chosen. In addition, they are able to have a beneficial effect on the course of microbiological soil processes. The positive effect of the durum wheat root system with the symbiosis of biofertilizers was noted. The experiment was carried out in 2018…2022. for land use of the peasant farm "Eliseev A.N", which is located in the black soil zone of the southern Mikhailovsky district of the Volgograd region. Studied varieties of hard spring wheat: Krasnokutka 13, Donskaya elegy and varieties of winter durum wheat: Agat Donskoy and Aksinit with the use of biofertilizers and mineral nutrition for given yield levels (according to the method of Dospekhov B.A., 2011). A five-year experiment has shown that biofertilizers (Blago +, Gumi 20) may well constitute an alternative to traditional mineral nutrition to obtain a given level of yield of hard spring and winter wheat varieties. The use of biofertilizers (as a less expensive means of purchasing them) will increase the yield up to 3.05 t/ha for the Donskaya elegia variety, and up to 3.84 t/ha for winter durum wheat Aksinit, using biofertilizer Gumi 20. Maximum yield level was obtained on the variant of the complex application of Gumi 20+N221P87K135 on the Aksinit variety, which amounted to 6.62 t/ha (with a planned yield of 6.00 t/ha). On varieties of spring durum wheat, the highest yield was obtained in variety Donskaya elegia (5.32 t/ha) on the variant of application of Gumi 20+N221P87K135.

ТЕХНОЛОГИЧЕСКИЕ АСПЕКТЫ ФОРМИРОВАНИЯ УРОЖАЙНОСТИ ТВЕРДОЙ ПШЕНИЦЫ В ЗОНЕ ЧЕРНОЗЕМА ЮЖНОГО ВОЛГОГРАДСКОЙ ОБЛАСТИ

Relevance. In the course of the experiment, ways to improve technological techniques for increasing the yield of grain crops against the background of preserving the natural fertility of the soil have been developed. Modern varieties of grain crops were studied against the background of the use of new generation biologics. The object of research was traditional durum wheat varieties, zoned in the Lower Volga region and modern varieties, characterized not only by high plasticity and adaptability to arid conditions, but also capable of having a positive effect on the course of soil microbiological soil processes. Materials and methods. The experiment was conducted during 2018...2022 on the land use territory of the farm "Eliseev A.N.", located in the chernozem zone of the southern Mikhailovsky district of the Volgograd region. The subject of the study was the varieties of hard spring and winter wheat: Krasnokutka 13, Don elegia, Aksinite and Agate Donskoy with the use of biofertilizers and mineral fertilizers for the specified yields according to the recommended method of Dospekhova B.A. (2011). Results and conclusions. The conducted experiment for 5 years showed that along with the traditional use of calculated doses of mineral nutrition to obtain a given yield threshold for varieties of hard spring and winter wheat, new types of biofertilizers are rightfully an alternative to them. With less expensive funds for their purchase, they are able to bring the yield of spring durum wheat to 3.05 t / ha (Don Elegia variety) and winter durum wheat to 3.84 t / ha (Aksinit variety) with the use of biofertilizer Gumi 20. The effect of biofertilizers with the complex application of the above was more clearly reflected. The highest yield threshold was obtained on the Gumi 20+N221Р87К135 variant on the Aksinit variety and it amounted to 6.62 t/ha (with a planned yield threshold of 6.00 t/ha). In spring durum wheat varieties, the maximum yield was obtained on the Don Elegia variety (5.32 t/ha) using the Gumi 20+N221Р87К135 variant. Based on the analysis of the obtained yield data, conclusions were formulated about the mechanism of obtaining the specified yield thresholds of different durum wheat varieties belonging to the spring and winter type.

Quantifying biomass and whole crop macro-nutrient accumulation for six hard spring wheat genotypes grown under different nitrogen rates at ambient and elevated carbon-dioxide levels

Atmospheric carbon dioxide concentrations ([CO2]) are increasing, but little is known about how this will affect macronutrient (nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)) accumulation and partitioning in the aboveground biomass (AGB) for different hard spring wheat genotypes. We examined the responses of six spring wheat genotypes (‘Discovery’, ‘Duchess’, ‘Reliance’, PFR-3026, PFR-3019, PFR-2021) to two CO2 levels (ambient [aCO2] and elevated [eCO2]) and six nitrogen rates (N; 1–10 mM), at the stem elongation growth stage of wheat grown in controlled environment chambers. The AGB yield increased by 35.2% with increasing [CO2] when N rate was >2 mM. Increasing N supply also increased AGB by up to 3.2-fold over the entire N range applied. The AGB responses to N differed among the genotypes, being lowest for PFR-3019 (7.71 ± 0.11 g/pot) and highest for PFR-2021, PFR-3026 and Duchess at 8.84 ± 0.11 g/pot at both CO2 levels. Macronutrient concentrations decreased with eCO2 by 28.0% for Ca to 17.4% for P and K. Nevertheless, absolute nutrient uptake was higher for eCO2 treatments, because the AGB increase (20.0–52.0%) was proportionally higher than the 4.0–28.0% increase in nutrient uptake. The AGB non-response to [CO2] at N rates <2mM indicates that this nutrient deficiency was more limiting than the effects of CO2 level. Therefore, the impact of eCO2 in the future will depend on N fertilizer management. These results suggest that critical nutrient concentrations used to diagnose the nutrient status of wheat crops will need to be reassessed for eCO2 conditions.

Quantifying nutrient harvest indices and uptake patterns for six hard spring wheat genotypes grown under contrasting nitrogen supply

ABSTRACT Wheat nutritional quality can be characterised by nutrient concentrations in the grain. This is the sum of nutrient uptake by the roots and re-translocation from other organs during grain filling. It is quantified by the Nutrient Harvest Index (NuHI: the fraction of total accumulated nutrient that is allocated to the grain). In contrast to nitrogen (NHI), there has been little quantification of NuHIs among modern hard spring wheat genotypes, when grown under contrasting N supply. We investigated NuHIs for six macro- and four micro-nutrients among six hard spring wheat genotypes, both under field and glasshouse conditions. There was consistency in element-specific NuHI values between experiments and amongst genotypes. Values ranged from 0.09 to 0.86, with highest NuHI found for phosphorus (P; 0.86) and N (0.82) and lowest values (<0.25) for calcium, copper, iron and potassium. NuHIs were higher under low N supply for all elements, except P, manganese and zinc, which were unaffected by N supply. This reflects the greater deposition of carbohydrate in higher yielding (N fertilised) crops. Thus, NuHIs for the hard spring wheat genotypes tested were highly element specific, and decreased with N supply within a given environment. HIGHLIGHTS Nutrient Harvest Index (NuHI) was similar between field and controlled environment NuHIs were consistent across six modern spring wheat genotypes NuHIs were in large element-specific ranging from 0.09 for potassium to 0.86 for phosphorus Limited N supply increased NuHIs mainly through reduced grain yield

Effect of thoracic stiffness on chest compression performance - A prospective randomized crossover observational manikin study

IntroductionHuman thoracic stiffness varies and may affect the performance during external chest compression (ECC). The Extra Compression Spring Resusci® QCPR Anne manikin is a high-fidelity training model developed for ECC training that can account for varying levels of thoracic stiffness. The aim of this study was to use this training model to investigate the effects of thoracic stiffness on ECC biomechanics and qualities. MethodsFifty-two participants performed standard ECC on the manikin with different thoracic springs to simulate varying levels of thoracic stiffness. The MatScan Pressure Measurement system was used to investigate the ECC pressure and force distribution. ResultsThe hard spring group’s performance had a better complete recoil ratio (90.06 ± 24.84% vs. 79.75 ± 32.17% vs. 56.42 ± 40.15%, p < 0.001 at second minute), but was more inferior than the standard and soft spring groups in overall quality, ECC depth (34.17 ± 11.45 mm vs. 41.25 ± 11.42 mm vs. 51.88 ± 7.56, p < 0.001 at second minutes), corrected depth ratio, and corrected rate ratio. The hard spring group had less radial-ulnar peak pressure difference (kgf/cm2) than the other two groups (−0.28 ± 0.38 vs. −0.30 ± 0.43 vs. −0.47 ± 0.34, p = 0.01), demonstrating that more symmetrical pressure was applied in the hard spring group. The soft spring group had better ECC depth, corrected depth ratio, corrected rate ratio, and overall quality, but its performance in complete recoil was inferior, and unbalanced pressure was more liable to cause injury. Hard springs caused operator fatigue easily. ConclusionThe thoracic stiffness greatly affected the performance of ECC. Our findings provided information for more effective ECC practices and training.

Population structure and genetic diversity of U.S. wheat varieties.

The United States is a major wheat producer with more than a century of wheat (Triticum aestivum L.) research and breeding. Using a panel of 753 historical and modern wheat varieties grown in the United States from the early 1800s to present day, we examined population structure and changes in genetic diversity. We used previously mapped high-quality single-nucleotide polymorphism (SNP) markers from the wheat 90K SNP array for genotyping. The wheat varieties had a slight hierarchical population structure based on growth habit and then by kernel color within spring varieties and by kernel hardness within winter varieties, which corresponds with geographical distribution of the varieties. Classifying varieties by market class, which is a combination of habit, hardness, and color, accounted for the greatest amount of variation (13.3%). We did not find evidence of decreased genetic diversity of either spring or winter varieties after the release of the first semidwarf wheat variety in 1961. On the contrary, northern and Pacific spring varieties, hard red spring (HRS), hard white spring (HWS), and soft white winter (SWW) had increases in both SNP and haplotype genetic diversity after 1961. The soft white spring (SWS) and soft red winter (SRW) market classes already had high genetic diversity in varieties before 1961 and showed some evidence of decreased diversity after 1961. Examination of temporal trends in genetic diversity also did not indicate long-term decline in diversity despite occasional fluctuations.

Clean-label breadmaking: Size exclusion HPLC analysis of proteins in dough supplemented with additives vs hard red spring wheat flour

Currently, there is a challenge for clean-label bread formulations to find replacements for dough improvers. For pan bread traditionally made from hard winter wheat, the addition of hard spring wheat flour may be an option to replace some dough improvers. Protein composition and properties of hard red spring wheat dough that would improve the quality of winter wheat dough for the purpose of replacing dough improvers need to be investigated. Therefore, this research aimed to compare molecular weight distribution (MWD) of unreduced proteins in dough samples that were made of a base hard red winter wheat flour supplemented with hard red spring (HRS) wheat flour or common additives such as potassium bromate, azodicarbonamide, ascorbic acid, sodium stearoyl lactylate, vital wheat gluten, non-fat dry milk, and others. The incorporation of the artificial additives significantly (p < .05) increased the quantity of total high molecular weight protein polymers (HMW-PP) in base-flour dough samples, which led to the improvement of breadmaking quality. Nonetheless, the HRS wheat flour naturally contained better protein quantity and quality, which sequentially contributed to forming more HMW-PP and a stronger gluten network in the dough than the base flour dough containing artificial additives. This research reported novel information on the variation of protein MWD in dough samples, especially those supplemented with artificial additives. The results support that the HRS wheat flour is an adequate choice as a blending flour to produce a clean-label bread substituting artificial additives.

Wheat yield and protein estimation with handheld‐ and UAV‐based reflectance measurements

AbstractPrecision agriculture provides efficient means of obtaining real‐time data to guide nitrogen (N) management based on predicted crop profitability. This study was conducted to assess the efficacy of using in‐season measurements (plant height, biomass weight, biomass N, soil plant analysis development [SPAD], GreenSeeker [GS] normalized difference vegetative index [NDVI], and unmanned aerial vehicle [UAV] NDVI) at Feekes 5 (tillering) and Feekes 10 (anthesis) to estimate wheat (Triticum aestivum L.) yield and protein. The secondary aim was to determine whether the accuracy of yield and protein prediction varies by wheat class and cultivar. Six cultivars—hard red spring (HRS) wheat ‘Jefferson’ and ‘SY Basalt’, hard white spring (HWS) wheat ‘Dayn’ and ‘UI Platinum’, and soft white spring (SWS) wheat ‘Seahawk’ and ‘UI Stone’—were planted at two locations in Idaho in 2018–2020. Plots were arranged in a randomized complete block design with four replications with each cultivar evaluated at seven N rates (0, 50, 100, 150, 200, 250, and 300 kg N ha–1). The determination of the Pearson correlation coefficients revealed that all parameters were linearly correlated with yield except for SPAD at Feekes 5 and biomass weight at Feekes 10. Although estimation of in‐season grain protein remains a challenge, NDVI was strongly correlated with yield especially at Feekes 5. The accuracy of yield prediction was similar for all wheat classes. Comparable accuracy of yield estimation was achieved with GS NDVI and UAV NDVI. Both hand‐held and aerial‐based spectral measurements could be used to prescribe N rates to be applied during tiller formation when wheat yield can be optimized.