Polymer Barrier Research Articles

Impact of Selected Operating Conditions on the Optical Properties of Polymer Shields

The optical properties of polymer barriers used as machine covers and eye protection are extremely important for vision quality and user safety. The article presents the influence of liquid chemical substances at room temperature on the transparency of poly(methyl methacrylate) shields. UV/VIS spectroscopy was used to assess the impact of liquid chemical substances on the polymer’s permeability to visible, ultraviolet and infrared radiations. The tests showed that the contact of the poly(methyl methacrylate) sheath with liquid chemicals influences the transmittance of the PMMA surface to a limited extent, without thereby reducing the harmful effects of radiation on humans.

Application of monitoring method in the establishment and maintenance of gas cap injection barrier in a Oilfield

In order to make technical reserves for developing gas cap and buffer zone in A Oilfield and explore effective development methods of gas cap reservoir, according to the overall development idea of oil-gas ring, a field test of gas cap injection and polymer barrier development buffer zone in Layer B was carried out in the structural axis of South Block in 2006. The test adopted the development mode of gas cap injection and polymer barrier development buffer zone, that is, the barrier was established by injecting polymer solution at the oil-gas boundary to separate natural gas from crude oil in buffer zone and keep relatively stable. In this paper, the morphological changes during the establishment and maintenance of barriers are found out by means of monitoring.

Polyacrylate Decorating Poly(ethylene terephthalate) (PET) Film Surface for Boosting Oxygen Barrier Property

Polymeric barrier materials are critical in contemporary industries for food, medicine, and chemical packaging. However, these materials, such as PET films, are impeded by the optimization of barrier properties by virtue of molecular design. Herein, a new methyl methacrylate-methyl acrylate-diallyl maleate-maleic acid (MMA-MAc-DAM-MA) was synthesized to tailor the surface properties of PET films for maximizing oxygen barrier properties. During the MMA-MAc-DAM-MA coating and curing process, the chemical structure evolutions of MMA-MAc-DAM-MA coatings were characterized, indicating that the cross-linking conversion and proportion of –COOH groups are critical for the oxygen barrier properties of coatings. The inherent –COOH groups are transformed into designed structures, including intramolecular anhydride, inter-chain anhydride and retained carboxylic acid. Therein, the inter-chain anhydride restraining the activity of coated polymer chain mainly contributes to enhanced barrier properties. The thermal properties of novel coatings were analyzed, revealing that the curing behavior is strongly dependent on the curing temperatures. The impacts of viscosity of the coating solution, coating velocity, and coating thickness on the oxygen permeability (Po2) of the coatings were investigated using a gas permeability tester to explore the optimum operating parameters during practical applications, which can reduce the Po2 of PET film by 47.8%. This work provides new insights on advanced coating materials for excellent barrier performance.

Functionalised graphene oxide-bromobutyl rubber composites with segregated structure for enhanced gas barrier properties

ABSTRACT Graphene-based elastomer composites with a segregated structure were prepared by electrostatic self-assembly. The morphology and microstructures of the composites were characterised by scanning electron microscope (SEM) and transmission electrical microscope (TEM). The segregated network leads to a low gas permeability coefficient for BIIR composites. With the incorporation as low as 0.4 wt-% GTA-GO, the helium permeability coefficient decreased about 63% when compared with that of neat BIIR. The tensile strength and percentage elongation increased with an increase in the GTA-GO content. This is attributed to the complete exfoliation, uniform dispersion and the segregated structure of GTA-GO in the BIIR matrix. These results demonstrate that such electrostatic self-assembly method between latex and sheet-fillers is an effective strategy to design and produce polymeric nanocomposites with good gas barrier properties. The results will effectively promote the application of barrier polymer in the production of protective clothing, gas storage devices and coatings.

Design of Novel PLA/OMMT Films with Improved Gas Barrier and Mechanical Properties by Intercalating OMMT Interlayer with High Gas Barrier Polymers.

Polymer/clay composites are an innovative class of materials. In this study, we present a facile method for the preparation of biodegradable and robust PLA/organomodified montmorillonite (OMMT) composite films with excellent gas barrier performance. When the design of PLA/OMMT composite films, in addition to making OMMT have good intercalation effect in the matrix, the compatibility of intercalating polymer and matrix should also be considered. In this work, two polymers with high gas barrier properties, namely poly(vinyl alcohol) (PVA) and ethylene vinyl alcohol copolymer (EVOH), were selected to intercalate OMMT. The morphology and microstructures of the prepared PLA/PVA/OMMT and PLA/EVOH/OMMT composites were characterized by the X-ray diffraction measurement, scanning electron microscopy, and differential scanning calorimetry. It was shown that the good dispersibility of PVA in the PLA matrix, rather than the intercalation effect, was responsible for the improved gas barrier and mechanical properties of PLA/PVA/OMMT composite. The elongation at break increases from 4.5% to 22.7% when 1 wt % PVA is added to PLA/OMMT. Moreover, gas barrier of PLA/PVA1/OMMT measured as O2 permeability is 52.8% higher than that of neat PLA. This work provides a route to intercalate OMMT interlayer with high gas barrier polymers and thus can be a useful reference to fabricate PLA/OMMT composites with improved gas barrier and mechanical properties. A comparison of oxygen permeabilities with existing commercial packaging films indicates that the biodegradable PLA/PVA/OMMT may serve as a viable substitute for packaging film applications.

Activation of Mechanophores in a Thermoset Matrix by Instrumented Scratch.

Scratches in polymer coatings and barrier layers negatively impact optical properties (haze, light transmission, etc.), initiate routes of degradation or corrosion (moisture permeability), and nucleate delamination of the coating. Detecting scratches in coatings on advanced materials systems is an important component of structural health monitoring but can be difficult if the defects are too small to be detected by the naked eye. The primary focus of the present work is to investigate scratch damage using fluorescence lifetime imaging microscopy (FLIM) and mechanical activation of a mechanophore (MP)-containing transparent epoxy coating. The approach utilizes a Berkovich tip to scratch MP-epoxy coatings under a linearly increasing normal load. The goal is to utilize the fluorescent behavior of activated MPs to enable the detection of microscale scratches and molecular scale changes in polymeric systems. Taking advantage of the amine functionality present in a polyetheramine/bisphenol A epoxy network, a modified rhodamine dye is covalently bonded into a transparent, thermoset polymer network. Following instrumented scratch application, subsequent fluorescence imaging of the scratched MP-epoxy reveals the extent of fluorescence activation induced by the mechanical deformation. In this work, the rhodamine-based mechanophore is used to identify both ductile and fracture-dominated processes during the scratch application. The fluorescence intensity increases linearly with the applied normal load and is sensitive to fracture dominated processes. Fluorescence lifetime and hyperspectral imaging of damage zones provide additional insight into the local (nanoscopic) environment and molecular structure of the MP around the fracture process zone, respectively. The mechanophore/scratch deformation approach allows a fluorescence microscope to probe local yielding and fracture events in a powerful way that enhances the optical characterization of damage zones formed by standard scratch test methods and leads to novel defect detection strategies.

(Invited) Immobilization of Nanobodies with Vapor-Deposited Polymer Encapsulation for Robust Biosensors

To produce next-generation, shelf-stable biosensors for point-of-care diagnostics, it is imperative to achieve rugged biomolecular recognition elements as well as innocuous deposition approaches for efficient encapsulants. Moreover, to maintain the sensitivity and specificity that is inherent to biological recognition elements in solid-state biosensing systems, site-specific immobilization chemistries must be invoked such that the function of the biomolecule remains unperturbed. In this work, we present a universally applicable strategy to establish robust solid-state biosensors using emergent nanobody (Nb) recognition elements with a vapor-deposited polymer encapsulation layer. As compared to conventional immunoglobulin G (IgG) antibodies, Nbs have multiple advantages, including higher thermal stability and pH tolerance, greater ease of recombinant production, and capable of binding antigens with high affinity and specificity. Photoinitiated chemical vapor deposition (piCVD) provides thin, protective polymer barrier layers over immobilized Nb arrays that allow for retention of biosensing activity and specificity after both storage under ambient conditions and complete desiccation. Most importantly, we also demonstrate that vapor-deposited polymer encapsulation of Nb arrays enables specific detection of target proteins, while suppressing nonspecific binding interactions in complex heterogeneous samples, such as unpurified cell lysate, which is otherwise challenging to achieve with bare Nb arrays. Figure 1

Preparation and evaluation of polymeric beads composed of Chitosan\u2013Gellan Gum\u2013Gum Ghatti/-Gum Karaya polyelectrolyte complexes as polymeric carrier for enteric sustained delivery of Diclofenac sodium

BackgroundAn enteric coating is a multistep technique that involves deposition of a polymeric barrier over uncoated orally administered tablets to prevent them from dissolving or disintegrating in the stomach. However, as soon as the coating dissolves in the alkaline environment of intestine, the whole of the drug come in direct contact with gastric mucosa leading to irritation to distal parts of the gastrointestinal tract (GIT). Considering the above facts, there is clear need to develop a simple and effective enteric release formulation for gastric irritant drugs like Diclofenac sodium (DS). The goal of this study was to create enteric release polymeric polyelectrolyte complex (PEC) beads made up of cationic Chitosan (CH) and anionic Gellan Gum (GG) for sustained DS delivery to the intestine. The beads were prepared by extruding a solution of GG and Gum Ghatti (GT) or GG and Gum Karaya (GK) bearing DS into CH solution in 1% w/v acetic acid, with the help of a syringe fitted with a 18 gauge hypodermic needle.ResultsInstantly created spherical beads were dried in a hot air oven 60 °C overnight. In 0.1 M HCl and 6.8 pH phosphate buffer, the dried beads were tested for drug entrapment in the beads, in vitro swelling of beads and in vitro drug release studies from the beads. The % drug entrapment efficiencies (% DEE) of these PEC beads ranged from 59.54 ± 2.09 to 81.03 ± 4.22%. In 0.1 M HCl, the PEC beads swelled the least in vitro, but expanded significantly in phosphate buffer (pH 6.8). The in vitro release of Diclofenac sodium from different PEC beads in 0.1 M HCl was found to be less than 7.5 percent, whereas the release was sustained for 6 h in phosphate buffer (pH 6.8).ConclusionsFrom the experimental data, it may be concluded that these PEC beads can be useful as potential multiple-unit enteric release polymeric carrier systems for sustained delivery of gastric irritant drugs like Diclofenac sodium.

Monitoring of Lactate in Interstitial Fluid, Saliva and Sweat by Electrochemical Biosensor: The Uncertainties of Biological Interpretation

Lactate electrochemical biosensors were fabricated using Pediococcus sp lactate oxidase (E.C. 1.1.3.2), an external polyurethane membrane laminate diffusion barrier and an internal ionomeric polymer barrier (sulphonated polyether ether sulphone polyether sulphone, SPEES PES). In a needle embodiment, a Pt wire working electrode was retained within stainless steel tubing serving as pseudoreference. The construct gave linearity to at least 25 mM lactate with 0.17 nA/mM lactate sensitivity. A low permeability inner membrane was also unexpectedly able to increase linearity. Responses were oxygen dependent at pO2 < 70 mmHg, irrespective of the inclusion of an external diffusion barrier membrane. Subcutaneous tissue was monitored in Sprague Dawley rats, and saliva and sweat during exercise in human subjects. The tissue sensors registered no response to intravenous Na lactate, indicating a blood-tissue lactate barrier. Salivary lactate allowed tracking of blood lactate during exercise, but lactate levels were substantially lower than those in blood (0–3.5 mM vs. 1.6–12.1 mM), with variable degrees of lactate partitioning from blood, evident both between subjects and at different exercise time points. Sweat lactate during exercise measured up to 23 mM but showed highly inconsistent change as exercise progressed. We conclude that neither tissue interstitial fluid nor sweat are usable as surrogates for blood lactate, and that major reappraisal of lactate sensor use is indicated for any extravascular monitoring strategy for lactate.

Elastic complementary meta-layer for ultrasound penetration through solid/liquid/gas barriers

Efficient ultrasound transmission is crucial in vast areas including noninvasive surgery, structural health monitoring, and underwater detection. However, extreme impedance contrast of interfering media spanning from solid to liquid and even gas seriously harms ultrasound transmission efficiency. Here, we propose a complementary meta-layer (CML) to “virtually cancel out” not only dissimilar solid but also liquid and gas barriers for highly enhanced transmission through the barriers in wave propagation perspective. Our proposition is apparently the first elastic CML and it is uniquely designed in a monolayer. The meta-atom forming a single meta-layer consists of spatially separated dipolar and monopolar resonators with completely independent tunability of effective negative properties. The proposed CML is capable of enhancing the ultrasound transmission by 593%, 1426%, and 3280% respectively for the polymer, water, and air barriers by numerical simulations. The proposed methodology to “cancel out” diverse barriers of highly dissimilar impedances can be groundbreaking in various ultrasound applications.

Air‐Stable Silicon Nanocrystal‐Based Photon Upconversion

AbstractPhoton upconversion may have the highest impact in biological applications because incoming photons transparent to tissue can be combined to make visible light useful for photodynamic therapy and imaging. The ability to use semiconductor nanocrystals as light absorbers for photon upconversion is important because their strong absorption profiles are synthetically tunable. In particular, the use of earth‐abundant, environmentally benign silicon quantum dots (QDs) as light absorbers for photon upconversion is very attractive. In this work, the authors demonstrate a general strategy employing both physical and chemical barriers to achieve air‐stable fusion of triplet excitons photosensitized by silicon QDs, crucial to practical applications of photon upconversion. Gel permeation chromatography (GPC) and dynamic light scattering (DLS) show that thermal hydrosilylation critical for colloidal stability and efficient triplet energy transfer creates a polymeric barrier to oxygen. This kinetic barrier to oxygen arises from the presence of cross‐linked surfactants and is complemented by the sacrificial oxidation of silicon QDs itself. Photon upconversion lasted longer than 4 days with quantum yields (QYs) as high as 7.5% (out of a maximum of 50%) using Si QD light absorbers with diphenylanthracene in methyl oleate. Oil‐in‐water micelles are air‐stable for 2 days with absolute upconversion QYs of 5.5%.

The Effect of Molecular Isomerism on the Barrier Properties of Polyimides: Perspectives from Experiments and Simulations.

A novel carbazole-containing diamine (M-2,7-CPDA) isomer of our previously reported diamine 2,7-CPDA, has been synthesized using a two-step synthesis. Compared with 2,7-CPDA, the substituted position of amino is changed from para to meta for M-2,7-CPDA. The two diamines were polymerized with pyromellitic dianhydride (PMDA) to prepare two isomeric polyimides (M-2,7-CPPI and 2,7-CPPI), respectively. The effects of para/meta isomerism on microstructures and gas barrier performances of the two isomeric polyimides were studied by positron annihilation test, X-ray diffraction and molecular simulation. The results display that meta-connected M-2,7-CPPI has less ordered chain structure and weaker hydrogen bonding than para-connected 2,7-CPPI, which leads to loose chain stacking and thereby increased free volumes of M-2,7-CPPI. The higher free volumes promote the solubility and diffusivity of gas in M-2,7-CPPI. As a result, the meta-linked M-2,7-CPPI shows a lower gas barrier than its para-linked analog. The work provides guidance for the design and synthesis of high-performance barrier polymers.

Ultra-high gas barrier composites with aligned graphene flakes and polyethylene molecules for high-pressure gas storage tanks

Despite polymers have great advantage in improving the energy density of hydrogen storage containers due to their lightweight characteristic, the production of high gas barrier polymers in a low-cost and high-efficiency manner remains a challenge. Here, polyethylene/graphene flakes (PE/GFs) composite films with ultra-high gas barrier properties were produced by no-boundary constraints hot-pressing method. Theoretical analysis showed that an extensional-shear coupled flow was generated inside the polymer melts and the shear-flow force near the polymer melts surface is always higher than that inside the melts during this process, which is responsible for the alignment of GFs and PE molecules. The DSC results indicated that the crystallinity of the composites after hot-pressing is increased by about 10%. The quantitative results of positron annihilation lifetime spectrum (PALS) showed that the fractional free volume of composites is reduced from 6.52 vol% to 5.43 vol%. As a consequence of the synergistic effect of the above aspects, the barrier performance of the composites has been significantly improved, and the helium leak rate of the composites reached an astonishing 3.92 × 10−9 Pa•m3/s with only 0.5 wt% GFs, outperforming unoriented pure PE with a decrease of 98.6%. Moreover, the tensile strength and Young's modulus of the oriented composites were increased by 31.4% and 21.1%, respectively. The work presented here demonstrates that the simple, fast, and economical preparation method can be readily used to produce composites with superior barrier performance, which will provide great reference for the processing technology of hydrogen storage containers.

Influence of Polymer Insulating Barriers on The AC Breakdown Behaviour of Small Oil Gaps.(Dept.E)

The paper reports the influence of some different, currently used, polymer Insulating barriers on the AC withstand voltage of small oil gaps. The experiments have been conducted using barrier Samples of bakelite (Ba), polystyrene (PS) and polyvinyl chloride (PVC). The insulating barriers have been inserted in small oil gaps subjected to AC high voltage stress of weakly as well as, of very highly divergent fields. The improvement of the dielectric strength of all gaps through the insertion of polymer barriers has been found to be dependent on the kind of barrier material, barrier placement in the gap, barrier dimensions as well as, on the degree of the field homogeniousity of the gap. plantations of the different parameter effects are attempted by considering the different possible space charge distributions as well as, the special features of the used dielectric polymers. The achieved results are, not only important for barrier effect considerations, but also can be helpful as a guide for the design of oil - solid composite dielectrics.

Novel high voltage polymer insulators using computational and data-driven techniques.

One of the key bottlenecks in the development of high voltage electrical systems is the identification of suitable insulating materials capable of supporting high voltages. Under high voltage scenarios, conventional polymer based insulators, which are one of the popular choices of insulators, suffer from the drawback of space charge accumulation, which leads to degradation in desirable electronic properties and facilitates dielectric breakdown. In this work, we aid the development of novel polymers for high voltage insulation applications by enabling the rapid prediction of properties that are correlated with dielectric breakdown, i.e.,the bandgap (Egap) of the polymer and electron injection barrier (Φe) at the electrode-insulator interface. To accomplish this, density functional theory based methods are used to develop large, chemically diverse datasets of Φe and Egap. The deviation of the computed properties from experimental observations is addressed using a statistical technique called Bayesian calibration. Furthermore, to enable rapid estimation of these properties for a large set of polymers, machine learning models are developed using the created dataset. These models are further used to predict Egap and Φe for a set of 13k previously known polymers. Polymers with high values of these properties are selected as potential high voltage insulators and are recommended for synthesis. Finally, the models developed here are deployed at www.polymergenome.org to enable the community use.

A comparative adsorption kinetic modeling of fluoride adsorption by nanoparticles and its polymeric nanocomposite

Nanoparticles (NPs) of metallic oxides/hydroxides (oxyhydroxide) are highly efficient adsorbents for pollutants but tend to agglomerate readily. So, in recent years, NPs have been embedded inside the porous polymeric matrix to decontaminate pollutants more efficiently than NPs alone. But the roles of the polymeric barrier on the performance of composite adsorbent have not been explored in literature. In the present study, diffusivity coefficients (De) of fluoride ions (F-) for adsorbents mixed metal oxyhydroxides and nanocomposite were estimated using a kinetic model to understand the roles of the polymeric barrier on adsorbate diffusion from the external surface to interior pores of the nanocomposite. Adsorption kinetic modeling study of both adsorbent-F- systems reveals that Fe-Al-Mn@chitosan composite is a more efficient adsorbent than mixed metal oxide nanoparticles alone. Although, the mass fraction of metal oxides/hydroxide present in the polymeric composite is less. The kinetic model reveals that only 25% of adsorption front radius was accessible for the adsorption of fluoride ions in mixed metal oxyhydroxide (Fe-Al-Mn) NPs. But, More than 80% of the total adsorption front radius was accessible for Fe-Al-Mn@chitosan. The magnitude of De is found to be almost in the same order for both the adsorbents, proving that polymer layers in Fe-Al-Mn@chitosan composite provide minimum resistance to the internal pore diffusion of adsorbate ions from the external surface to interior pores.

Immobilization of Nanobodies with Vapor-Deposited Polymer Encapsulation for Robust Biosensors.

To produce next-generation, shelf-stable biosensors for point-of-care diagnostics, a combination of rugged biomolecular recognition elements, efficient encapsulants, and innocuous deposition approaches is needed. Furthermore, to ensure that the sensitivity and specificity that are inherent to biological recognition elements are maintained in solid-state biosensing systems, site-specific immobilization chemistries must be invoked such that the function of the biomolecule remains unperturbed. In this work, we present a widely applicable strategy to develop robust solid-state biosensors using emergent nanobody (Nb) recognition elements coupled with a vapor-deposited polymer encapsulation layer. As compared to conventional immunoglobulin G antibodies, Nbs are smaller (12-15 kDa as opposed to ~150 kDa), have higher thermal stability and pH tolerance, boast greater ease of recombinant production, and are capable of binding antigens with high affinity and specificity. Photoinitiated chemical vapor deposition affords thin, protective polymer barrier layers over immobilized Nb arrays that allow for retention of Nb activity and specificity after both storage under ambient conditions and complete desiccation. Most importantly, we also demonstrate that vapor-deposited polymer encapsulation of Nb arrays enables specific detection of target proteins in complex heterogeneous samples, such as unpurified cell lysate, which is otherwise challenging to achieve with bare Nb arrays.

Thermal and electrical characterization of poly(vinyl)alcohol)/poly(vinylidene fluoride) blends reinforced with nano-graphene platelets

Nano-graphene/polymer composites can function as pressure induced electro-switches, at concentrations around their conductivity percolation threshold. Close to the critical point, the pressure dependence of the electron tunneling through the polymer barrier separating nano-graphene's results from the competition among shortening of the tunneling length and the increase of the polymer's polarizability. Such switching behavior was recently observed in polyvinyl alcohol (PVA) loaded with nano-graphene platelets (NGPs). In this work, PVA is blended with α-poly(vinylidene fluoride) (PVdF) and NGPs. Coaxial mechanical stress and electric field render the nano-composite piezoelectric. We investigate the influence of heterogeneity, thermal properties, phase transitions and kinetic processes occurring in the polymer matrix on the macroscopic electrical conductivity and interfacial polarization in casted specimens. Furthermore, the effect of electro-activity of PVdF grains on the electric and thermal properties are comparatively studied. Broadband Dielectric spectroscopy is employed to resolve and inspect electron transport and trapping with respect to thermal transitions and kinetic processes traced via Differential Scanning Calorimetry. The harmonic electric field applied during a BDS sweep induces volume modifications of the electro-active PVdF grains, while, electro-activity of PVdF grains can disturb the internal electric field that free (or bound) electric. The dc conductivity and dielectric relaxation was found to exhibit weak dependencies.

Effects of Corn Silage Inclusion Level and Type of Anabolic Implant on Animal Growth Performance, Apparent Total Tract Digestibility, Beef Production per Hectare, and Carcass Characteristics of Finishing Steers.

Simple SummaryCorn silage has long been a staple feed ingredient in cattle diets throughout the Midwest region of the United States. The most recent Feedlot Consulting Nutritionist Survey indicated that corn silage was the primary and secondary roughage source used in finishing diets by 37.5% of respondents. Using the entirety of the corn plant for feed allows for producers to quickly harvest feed tonnage. A common belief is that one should only include enough corn silage in a finishing ration to maintain rumen health. However, previous research conducted by our research group suggested that feeding increased levels of corn silage could increase the quantity of beef produced per hectare of cropland. Another aspect to consider when finishing cattle is implant type. Today a wide variety of implants are available, including polymer barrier coated and non-coated implants. Coated implants can provide an extended release of trenbolone acetate and estradiol for up to 200 days post-implantation. The objectives of the current study were to determine the influence of corn silage inclusion level and terminal implant type on animal growth performance, apparent total tract digestibility, carcass traits, and beef production per hectare of cropland in finishing steers harvested at common rib fat thickness.Maine-Anjou × Angus cross-bred steers (n = 156 steers; initial body weight (BW) 366 ± 37.2 kg) were used in a 132 d finishing study conducted at the Ruminant Nutrition Center (RNC) in Brookings, SD. Steers were blocked by weight (n = 5 BW blocks) and randomly assigned to an implant and dietary treatment of a randomized complete block design with each pen containing seven to eight steers (n = 20 pens). Dietary treatments consisted of (1) 15% (CS15) or (2) 30% corn silage (CS30) where corn silage displaced corn grain in the diet. Steers received one of two implants (both from Zoetis, Parsippany, NJ) containing equal doses of trenbolone acetate (TBA) and estradiol benzoate (EB): (1) Synovex PLUS (non-coated implant; 200 mg TBA and 28 mg EB; PLUS) or (2) Synovex ONE Feedlot (coated implant; 200 mg TBA and 28 mg EB; ONE-F). Bunks were managed using a slick bunk approach, and all diets contained dry matter (DM) basis 33 mg/kg monensin sodium. All steers were offered ad libitum access to feed, and feeding occurred twice daily in equal portions. There was no interaction between the implant and dietary treatment for any variables measured (p ≥ 0.08). Carcass-adjusted basis final BW, average daily gain (ADG), and grain to feed (G:F) were increased (p ≤ 0.02) by 2.2%, 6.5%, and 7.2%, respectively, for CS15. Observed net energy (NE) and the ratio of observed-to-expected NE for maintenance and gain was not influenced (p ≥ 0.15) by silage inclusion treatment. Beef production per hectare was not impacted (p ≥ 0.13) by corn silage inclusion level. Fecal output was increased, and digestibility coefficients for dry matter, organic matter, and crude protein were decreased in CS30 (p ≤ 0.03). Dressing percent and hot carcass weight (HCW) were greater (p ≤ 0.02) in CS15. Implant type did not influence any traits measured (p ≥ 0.14) except for marbling. Marbling was decreased for PLUS (433 vs. 466 ± 17.5; p = 0.02) compared to ONE-F steers. Similar beef produced per hectare of crop land-based upon silage feeding level means producers can feed greater inclusions of corn silage to finishing cattle without impacting carcass quality or beef production; implanting with a coated implant had no detrimental effects to growth performance but increases marbling scores.

Emulation of synaptic behavior by organic ferroelectric tunnel junctions

The synapses are essential to the brain neuromorphic system, and especially the plasticity of synapse contributes significantly in cognitive functions. Ferroelectric tunnel junction (FTJ) can be utilized to emulate the synaptic functions by the effective control of resistance state, which is related with the ferroelectric polarization state of barrier layer. Here, we study the emulation of a synaptic response in the fabricated organic ferroelectric tunnel junctions (OFTJs) with Polyvinylidene fluoride (PVDF) polymer barriers. The functions of long-term potentiation and long-term depression are demonstrated by exploring the relationship between resistance and polarizing pulse. In addition, our device can be also utilized to realize multi-memory function, a device with six-resistance states is demonstrated. Our results may provide a new degree of freedom for the realization of synaptic functions in OFTJs.