Pure Pea Research Articles

Ductility of a nanocomposite of glassy and rubbery polymers

A brittle glassy polymer can be made ductile by forming a nanocomposite with a rubbery polymer. This paper investigates a nanocomposite of poly(methyl methacrylate) (PMMA) and poly(ethyl acrylate) (PEA). Pure PMMA is a brittle glass, pure PEA is a rubber, and a PEA-PMMA nanocomposite is ductile. We fabricate the nanocomposite by swelling PEA with MMA monomer, followed by polymerizing MMA. We prepare nanocomposites of various weight fractions of PMMA and measure their properties, including modulus, yield strength, fracture strain, fracture strength, work of fracture, and toughness. Whereas bulk PMMA fractures at a strain of ∼0.05 by localizing inelastic deformation in crazes, the PEA-PMMA nanocomposite can be stretched several times its original length with homogeneous deformation. The nanocomposite separates into a glassy phase and a rubbery phase. For a nanocomposite of 45 % weight fraction of PMMA, atomic force microscopy shows that the two phases are bicontinuous and the phase size is at ∼20 nm. For the nanocomposite to undergo large deformation, the continuous glassy phase must accommodate. Our experiments exclude the mechanism that the glassy phase in the nanocomposite breaks into small pieces. Rather, the glassy phase in the nanocomposite is itself ductile. We discuss the molecular picture of this ductility.

Energy Efficiency of Oat:Pea Intercrops Affected by Sowing Ratio and Nitrogen Fertilization

This study analyzed energy input (direct and indirect), energy output, net-energy output, energy use efficiency, energy intensity, and the energy productivity of oat:pea intercrops as affected by sowing ratio (oat:pea (%:%): 100:0, 75:25, 50:50, 25:75, 0:100) and nitrogen (N) fertilization (0, 60, 120 kg N ha−1). The two year field experiment was conducted on a calcaric Chernozem soil in the north-western part of the Pannonian Basin. The results for grain yield showed that pure stands of oat and pea had a higher energy use efficiency and energy intensity than intercrops, indicating that pure stands used the growing factors more efficiently than intercrops. The energy use efficiency was higher in pure pea than pure oat. The energy productivity for the above-ground biomass production was much more affected by the factor N fertilization than by the factor sowing ratio. The highest energy productivity of grain N yield and above-ground biomass N yield was achieved in pure pea stands (0:100). N in plant residues of the zero N fertilization variant required 68% lower technical energy than N from mineral fertilizer. The sowing rate of the intercrops is a management tool to trade-off between the benefits of the in-field biodiversity and energy efficiency.

Effects of Weed Control Treatments on Weed Composition and Yield Components of Winter Wheat (Triticum aestivum L.) and Winter Pea (Pisum sativum L.) Intercrops

Intercropping is an ancient and worldwide agricultural practice expected to become more prevalent in Hungary due to the accumulating impact of climate change. In this study, the plant association of pure winter wheat (Triticum aestivum L.) and pure winter pea (Pisum sativum L.) was analyzed without weed control and with applied herbicides at different intervals (pre-emergence, early and late post-emergence) and different active herbicide ingredients. Two growing seasons, 2018–2019 and 2019–2020 were examined to compare weed composition and weed cover to evaluate the effect of the applied herbicides at different timings. To determine weed control efficiency, weed surveys were conducted six times in each growing season. The effect of cultivation methods (pure and mixed plots) on the development of plants was also measured by yield production analysis. Findings from these investigations indicate that there were significantly more weed species and occurrences of weeds in pure wheat and pure pea plots compared to mixed plots. In addition to cultivation and weed control treatments, meteorological events significantly influenced the development of the plants, and thus the yield components.

Impact of Konjac Glucomannan with Different Molecular Weight on Retrogradation Properties of Pea Starch.

The impact of konjac glucomannan (KGM) with different molecular weight (Mw) on the retrogradation properties of pea starch, such as color, viscoelasticity, gel strength, water holding capacity (WHC), moisture distribution and crystallinity, was investigated. At the same time as the Mw of KGM decreased, the lightness, elastic modulus, gel strength, water freedom and crystallinity of pea starch showed an increasing trend, whereas the viscosity modulus and WHC showed a decreasing trend. At one day of storage, compared with single pea starch, KGM with low Mw made gel strength increase from 40 g to 45 g, WHC decrease from 82% to 65% and crystallinity increase from 21.3% to 24.0%. Therefore, KGM with low Mw could promote retrogradation of pea starch in the short-term. At 7 days or even 14 days of storage, KGM with medium-high Mw had smaller indices than those of pure pea starch, including the lightness, storage modulus, gel strength, water freedom and crystallinity. This indicated that KGM with medium-high Mw could inhibit the long-term retrogradation of starch. The larger the Mw of KGM, the more noticeable the inhibition effect.

Non-destructive determination of grass pea and pea flour adulteration in chickpea flour using near-infrared reflectance spectroscopy and chemometrics.

In order to obtain more economic gains, some food products are adulterated with low-cost substances, if they are toxic, they may pose public health risks. This has called forth the development of quick and non-destructive methods for detection of adulterants in food. Near-infrared reflectance spectroscopy (NIRS) has become a promising tool to detect adulteration in various commodities. We have developed rapid NIRS based analytical methods for quantification of two cheap adulterants (grass pea and pea flour) in a popular Indian food material, chickpea flour. The NIRS spectra of pure chickpea, pure grass pea, pure pea flour and adulterated samples of chickpea flour with grass pea and pea flour (1-90%) (w/w) were acquired and preprocessed. Calibration models were built based on modified partial least squares regression (MPLSR), partial least squares (PLS), principal component regression (PCR) methods. Based on lowest values of standard error of calibration (SEC) and standard error of cross-validation (SECV), MPLSR-NIRS models were selected. These models exhibited coefficient of determination (R2 ) of 0.999, 0.999, SEC of 0.905, 0.827 and SECV of 1.473, 1.491 for grass pea and pea, respectively. External validation revealed R2 and standard error of prediction (SEP) of 0.999 and 1.184, 0.997 and 1.893 for grass pea and pea flour, respectively. The statistics confirmed that our MPLSR-NIRS based methods are quite robust and applicable to detect grass pea and pea flour adulterants in chickpea flour samples and have potential for use in detecting food fraud. © 2022 Society of Chemical Industry.

PEA*+IDA*: An Improved Hybrid Memory-Restricted Algorithm

It is well-known that the search algorithms A* and Iterative Deepening A* (IDA*) can fail to solve state-space tasks optimally due to time and memory limits. The former typically fails in memory-restricted scenarios and the latter in time-restricted scenarios. Therefore, several algorithms were proposed to solve state-space tasks optimally using less memory than A* and less time than IDA*, such as A*+IDA*, a hybrid memory-restricted algorithm that combines A* and IDA*. In this paper, we present a hybrid memory-restricted algorithm that combines Partial Expansion A* (PEA*) and IDA*. This new algorithm has two phases, the same structure as the A*+IDA* algorithm. The first phase of PEA*+IDA* runs PEA* until it reaches a memory limit, and the second phase runs IDA* without duplicate detection on each node of PEA*'s Open. First, we present a model that shows how PEA*+IDA* can perform better than A*+IDA* although pure PEA* usually makes more expansions than pure A*. Later, we perform an experimental evaluation using three memory limits and show that, compared to A*+IDA* on classical planning domains, PEA*+IDA* has higher coverage and expands fewer nodes. Finally, we experimentally analyze both algorithms and show that having higher F-limits and better priority-queue composition given by PEA* have a considerable impact on the performance of the algorithms.

A low nitrogen fertiliser rate in oat–pea intercrops does not impair N2 fixation

ABSTRACT Intercropping is commonly used in low-input systems but could also be a strategy for higher input systems. Three ratios of substitutive oat–pea intercrops were tested on a fertile soil in eastern Austria with application of a low nitrogen (N) fertiliser rate (6 g N m−2) versus an unfertilised control to assess the effect of intercropping and low N fertilisation on dinitrogen fixation (NFIX). The above-ground dry matter (AGDM) and N yield of intercrops increased with N fertilisation, but the increase occurred only in oat, while pea was not affected by N fertilisation. Pure pea stands and intercrops with high pea share resulted in N sparing in the soil at harvest, as the soil mineral N was higher than in pure oat. Half of the applied amount of N was recovered by the AGDM of crops and half remained in the soil at harvest. The NFIX per unit area was highest in pure pea. Intercropping considerably reduced NFIX, especially in intercrops with low pea share. NFIX per unit of AGDM of pea, however, was neither affected by intercropping nor by N fertilisation. Consequently, a low amount of N fertilisation of oat–pea intercrops on a fertile soil can increase overall performance of the system through increasing the performance of oat without impairing that of pea.

Cyclic strength of polyester acrylate composites

The results of a study of the cyclic strength of polyester-racrylate composites are presented. The mechanical properties of the samples were determined on a Shimadzu Autograph AG-X Series universal testing machine. Test process management and pre-processing of data obtained on this machine are performed using the TRAPEZIUM X * 1 software. The measurements were carried out with a constant velocity of movement of the active capture of 3 mm / min. The compression force was directed along the long axis of the sample. The cyclic mechanical impact on the sample was carried out according to the following scheme: “loading to a certain maximum stress σmax in a given cycle → complete unloading at the same speed → five times repeating the cycle with a given load σmax → repeating the five times cycling procedure with a stepwise change in maximum load σmax until the sample is destroyed. It is shown that a characteristic feature of the load – strain curves during cycling is the presence of hysteresis, which is especially significant in the first cycle. The first compressive loading of the sample leads to significant changes in the structure of PEA. In the second and subsequent cycles, the difference between the loading and unloading curves of the sample is noticeably smaller and depends little on the cycle number. Then the state of the sample is stabilized, and subsequent cycling affects it much weaker. It is characteristic that the maximum difference between the losses in the first and subsequent cycles is observed at the minimum initial voltage. At maximum loads, the unloading curve is steeper than the loading curve, and at low loads, vice versa. Hysteresis losses increase with increasing maximum load in the cycle, which corresponds to an increase in the contribution of the plastic component to the total deformation of the sample. The E (σ) dependences obtained during loading in the first cycle practically coincide with the loss curves. In subsequent cycles, a slight quantitative change in these curves is observed without changing their general nature. The dependences obtained by unloading the samples are fundamentally different from the dependences obtained by loading. In this case, the discrepancy between the E (σ) curves during loading and unloading in the composite is slightly weaker than in pure PEA.

Impact of crop stand, Rhizobium inoculation, and foliar fertilization on pea root parameters

Summary Ecological intensification of crop production involves the use of intercrops and the rational use of inoculation and fertilization in case of intercrops including legume species. The root system plays an important role in the productivity of crops. Therefore, effects of the inoculation treatments (Nitragina) or foliar fertilization (Photrel) or a combination of both were assessed on root parameters of pea grown as pure stand or intercrops with linseed or wheat in a 3-year experiment in Poland. Crop stand composition influenced the root parameters of pea with a higher root length density (RLD) in the root fractions of 0.1–1 mm of pea in pea/linseed intercrops than in the pure stand, a higher mean root diameter (MRD) in pure pea and intercrops of pea with linseed than with wheat, and also a tendency of a higher root dry matter (RDM) in pure pea and pea/linseed than in pea/wheat in 2 out of the 3 years. RLD was higher with Photrel than with Nitragina in root fractions of 0.1–0.5 mm. Treatments did not affect the MRD, but a combination of Nitragina + Photrel increased the RDM in 1 year. Intercropping of pea with linseed and the application of a foliar fertilizer might be a strategy to improve pea root characteristics.

Cell wall components and in vitro dry matter digestibility of ensiled pea: Oat mixtures

Cell wall content generally is regarded as the most important factor affecting forage utilization because it comprises the major fraction of forage dry matter and is correlated with forage intake and digestibility. The experiment was carried out to evaluate the cell wall constituents of ensiled pea - oat mixtures sown at five different seeding rates. Three effects were studied: application of bacterial inoculant, seeding rate of pea and oat in the mixtures and stages of plant development. The NDF (Neutral Detergent Fiber), ADF (Acid Detergent Fiber), hemicellulose, lignin and DMD (Dry Matter Digestibility) were determined in silages. Pea and oat were grown in binary mixtures at the experimental field of the Institute for forage crops, Krusevac - Serbia, and were tested at five different mixture rates: pure pea and pure oat crop, 25% pea + 75% oat, 50% pea + 50% oat, 75% pea + 25% oat. Application of bacterial inoculant affected lower content of NDF and hemicellulose (P< 0.05). Content of cell wall constituents decreased with increasing pea content in the mixtures, but DMD increased. On the other hand, content of cell wall constituents increased with plant growth and development, but DMD decreased.

PEA/V-SiO2 core-shell structure for superhydrophobic surface with high abrasion performance

Organic/inorganic core-shell nanostructure of PEA/V-SiO2 emulsion has been firstly synthesized along with comparison of conventional SiO2 and pure PEA materials . Their chemical bondings and morphology properties have been observed though characterization methods such as transmission electron microscopy, X-ray photon spectrum and infrared spectrum, etc. The nanoparticle of mean diameter within 200 nm has been obtained that was well dispersed into the pure solvent. After that, the water repelling textile has been prepared to measure the surface contact angle which reached above 151.5°. The super hydrophobic function abrasion resistance is also characterized and such improvement is attributed to the highly entanglements and nanostructure established by PEA/V-SiO2 above the textile surface.

The rheological and microstructural properties of pea, milk, mixed pea/milk gels and gelled emulsions designed by thermal, acid, and enzyme treatments

The rheological and microstructural properties of pure pea, pure milk, and mixed pea/milk gels were investigated and compared. Three gelation techniques were used: a thermal treatment, an acid treatment employing glucono delta-lactone, and an enzyme treatment employing chymosin and transglutaminase. Considerable differences in the gels' rheological and microstructural properties were observed. The thermally induced pure pea and mixed gels had comparable rheological and microstructural properties, suggesting the existence of interactions between pea and whey proteins. The enzyme-induced gels had a higher strain at rupture, a property that was associated with the presence of coarse aggregates. Within this gel type, mixed gels displayed a lower storage modulus than did pure pea or pure milk gels. Among acid-induced gels, pure pea gels were much stiffer than pure milk or mixed gels, probably because their final pH was lower. The addition of fat strengthens the mechanical properties of all pea gels studied, in particular in the mixed gels obtained by acid and enzyme gelation. The microstructural differences were consistent with the rheological differences. These results provide insight into the formation of gels via these gelation techniques and could inform the formulation of new food products that are enriched in plant protein.

Influence of heat on miscibility of Quillaja saponins in mixtures with a co-surfactant

Thermal treatment of mixed surfactant systems can have a major impact on their phase behavior through modified interactions between the surfactants. In this study, we investigated the miscibility behavior of aqueous binary surfactant systems composed of Quillaja saponin extract and sodium caseinate, pea protein, rapeseed lecithin, or egg lecithin at different concentration ratios (0–5% w/v) at pH3, 5, and 7 upon heat treatment (25–75°C). The results revealed that the heat-treated Quillaja saponin–sodium caseinate mixtures at pH7 remained miscible when the ratio of Quillaja saponins was equal or higher to the ratio of caseinate, otherwise the mixtures flocculated due to increased hydrophobic interactions. At pH3, the aggregation of Quillaja saponin–sodium caseinate structures was intensified by heating mainly through self-association of casein molecules. In Quillaja saponin–pea protein mixtures as well as in pure pea protein samples heating led to weakening of the gel structures at all tested pH values. In contrast, heating did not affect Quillaja saponin–rapeseed lecithin mixtures, which stayed miscible independent of pH due to electrostatic repulsive forces. Furthermore, the flocculated (pH5, 7) or aggregated (pH3) Quillaja saponin–egg lecithin mixtures were only slightly affected by heating. These results are important for understanding the interactions of binary surfactant systems when subjected to heating, which is a common processing step in many food applications.

Synergistic enhancement in the co-gelation of salt-soluble pea proteins and whey proteins

This paper investigated the enhancement of thermal gelation properties when salt-soluble pea proteins were co-gelated with whey proteins in NaCl solutions, using different blend ratios, total protein concentrations, pH, and salt concentrations. Results showed that the thermal co-gelation of pea/whey proteins blended in ratio of 2:8 in NaCl solutions showed synergistic enhancement in storage modulus, gel hardness, paste viscosity and minimum gelation concentrations. The highest synergistic enhancement was observed at pH 6.0 as compared with pH 4.0 and 8.0, and at the lower total protein concentration of 10% as compared with 16% and 22% (w/v), as well as in lower NaCl concentrations of 0.5% and 1.0% as compared with 1.5%, 2.0%, 2.5%, and 3.0% (w/v). The least gelation concentrations were also lower in the different pea/whey protein blend ratios than in pure pea or whey proteins, when dissolved in 1.0% or 2.5% (w/v) NaCl aqueous solutions.

Fibrous biodegradable l-alanine-based scaffolds for vascular tissue engineering

In vascular tissue engineering, three-dimensional (3D) biodegradable scaffolds play an important role in guiding seeded cells to produce matrix components by providing both mechanical and biological cues. The objective of this work was to fabricate fibrous biodegradable scaffolds from novel poly(ester amide)s (PEAs) derived from l-alanine by electrospinning, and to study the degradation profiles and its suitability for vascular tissue-engineering applications. In view of this, l-alanine-derived PEAs (dissolved in chloroform) were electrospun together with 18-30% w/w polycaprolactone (PCL) to improve spinnability. A minimum of 18% was required to effectively electrospin the solution while the upper value was set in order to limit the influence of PCL on the electrospun PEA fibres. Electrospun fibre mats with average fibre diameters of ~0.4 µm were obtained. Both fibre diameter and porosity increased with increasing PEA content and solution concentration. The degradation of a PEA fibre mat over a period of 28 days indicated that mass loss kinetics was linear, and no change in molecular weight was found, suggesting a surface erosion mechanism. Human coronary artery smooth muscle cells (HCASMCs) cultured for 7 days on the fibre mats showed significantly higher viability (p < 0.0001), suggesting that PEA scaffolds provided a better microenvironment for seeded cells compared with control PCL fibre mats of similar fibre diameter and porosity. Furthermore, elastin expression on the PEA fibre mats was significantly higher than the pure PEA discs and pure PCL fibre mat controls (p < 0.0001). These novel biodegradable PEA fibrous scaffolds could be strong candidates for vascular tissue-engineering applications.

Water sorption properties of poly(ethyl acrylate‐co‐hydroxyethyl methacrylate) macroporous hydrogels

AbstractSynthetic porous hydrogels are becoming more and more important in the field of biomaterials. Different studies demonstrate that the porous structure promotes the colonisation of living cells and improves the biocompatibility of the implants. The macroporous structure allows not only the control of cellular ingrowth morphology but also the mechanical integration and the regulation of nutrient and hydraulic flow in the hydrogel. In this work poly(ethyl acrylate‐co‐hydroxyethyl methacrylate) (PEA/PHEMA) copolymers were polymerized using 2% of ethylene glycol dimethacrylate as cross‐linking agent and azoiso‐botyronitrile as initiator. Five samples were prepared with the EA/HEMA weight ratios of 75/25, 50/50, 25/75 and pure PEA and PHEMA polymers, obtaining different degrees of hydrophilicity. The macroporous structure was obtained by adding poly(acrylonitrile) fibres to the monomers. After polymerization the fibres were eliminated by dissolution in dimethyl formamide. The holes are cylinders of approximately 40μm diameter and are all, more or less, in the same direction, although they are not uniformly distributed. Water sorption isotherms and diffusion properties of the macroporous samples are compared with the samples without holes.

Weed Suppression in Spring-Sown Rye (Secale cereale)–Pea (Pisum sativum) Cover Crop Mixes1

Abstract: Field trials were conducted with spring-sown rye and field pea cover crops to determine the effect of five rye–pea proportions and three seeding rates (high, medium, and low) on weed suppression during cover crop growth. Measurements on weed and cover crop growth were taken approximately 2 mo after seeding when cover crops were killed. Cover crops were killed by mowing in 1996 and by undercutting in 1997 and 1998. Cover crop biomass, averaged over rye–pea proportion, was highest in 1998 at 4.3 million tons (MT)/ha (high seeding rate) and lowest in 1997 at 1.5 MT/ha (low seeding rate). Cover crops of pure rye or rye–pea mixes suppressed weeds more effectively than did pure pea. Dominant weeds were ladysthumb, smooth pigweed, smallflower galinsoga, and common lambsquarters. Ground cover by weeds ranged from a low of 2% (rye–pea mixes) to a maximum of 73% (pure pea). Cover crop mixes of 50% or more rye seeded at the high rate gave the best weed suppression. Nomenclature: Ladysthumb, Polygonum persi...

Characterizing domain mixing effects in hydrogen bond‐compatibilized polymer blends

AbstractThe nature and extent of phase mixing in blends of hydroxyl‐functionalized polystyrene and poly(ethyl acrylate) (PS/PEA), where the driving force for mixing is hydrogen bonding, are characterized by several techniques. Small‐angle x‐ray scattering (SAXS) shows a reduction in average domain size with increasing functionalization level, a result also evident from scanning electron microscopy (SEM). Together, the two techniques reveal a very broad distribution of domain sizes. At high functionalization levels, both SAXS and SEM indicate a high degree of “in‐domain” mixing, with little or no pure PS or PEA remaining in the blends. Mathematical modeling of dynamic mechanical thermal analysis (DMTA) data is employed to quantify this progression. Initially, mixing is primarily interfacial, but as the functionalization level increases, the mixed interphase rapidly grows to occupy the entire material. In agreement with the SAXS and SEM results, DMTA modeling shows that further increases in the functionalization level suppress the amplitude of composition variations in the sample. The onset of extensive in‐domain mixing coincides with the marked changes in stress‐strain behavior observed previously in these materials. © 1994 John Wiley &amp; Sons, Inc.

A comparison of faba beans and peas as whole‐crop forages

AbstractFaba beans and peas were compared as spring sown whole‐crop forages in two trials at Lough‐gall. No herbicide, insecticide or N fertilizer was used. Harvesting took place at the end of July. As pure stands, tic beans (cv. Blaze) yielded up to 10 t of dry matter (DM) ha−1. Lower yields were obtained at lower seed rates, or with horse beans (cv. Stella Spring), broad beans (cv. Polar) or peas (cvs Minerva and Krupp). Tic and horse bean forage had a mean DM concentration of 166 g kg−1, which was higher than those of broad bean and peas. Crude protein (CP) concentration at a mean of 159 g kg−1 was similar in tic beans and peas. Faba beans mixed with cereals yielded less than beans alone, but peas with cereals yielded slightly more than peas alone. The inclusion of a cereal raised forage DM contents but lowered CP contents. Perennial ryegrass‐white clover mixtures undersown in faba beans established well, but poorer swards were obtained in some of the pure pea stands which lodged severely. It is concluded that, as pure stands, tic beans have advantages over peas. Some of the disadvantages of peas can be overcome by growing a mixture of peas with cereals.