Methods for determining color characteristics of vegetable raw materials. A review

Food product quality defines a complex of food product properties such size, shape, texture, color and others, and determines acceptability of these products for consumers. It is possible to detect defects in plant raw materials by color and classify them by color characteristics, texture, shape, a degree of maturity and so on. Currently, the work on modernization of color control systems has been carried out for rapid and objective measuring information about color of plant raw materials during their harvesting, processing and storage. The aim of the work is to analyze existing methods for determining color characteristics of plant raw materials described in foreign and domestic studies. Also, this paper presents the results of the experimental studies that describe the practical use of methods for measuring food product color. At present, the following methods for determining color characteristics by the sensor analysis principle are used: sensory, spectrophotometric and photometric. These methods have several disadvantages. Therefore, computer vision has found wide application as an automated method for food control. It is distinguished by high confidence and reliability in the process of determining freshness, safety, a degree of maturity and other parameters of plant raw materials that are heterogeneous in terms of the abovementioned indicators. The computer vision method is realized in the following systems: conventional, hyperspectral and multispectral. Each subsequent system is a component of the preceding one. Materials presented in the paper allow making a conclusion about the effectiveness of the computer vision systems with the aim of automatic sorting and determining quality of plant raw materials in the food industry.

Water-soluble CMY primary color electrochromic polymers: Design, Synthesis and Full Color Control

The next generation of electrochromic materials are required to be rich in color rendering, excellent processability and environmental protection. Soluble electrochromic polymer (ECP) can fulfill these requirements. However, a more...

The role of contextual materials in object recognition

While scene context is known to facilitate object recognition, little is known about which contextual “ingredients” are at the heart of this phenomenon. Here, we address the question of whether the materials that frequently occur in scenes (e.g., tiles in a bathroom) associated with specific objects (e.g., a perfume) are relevant for the processing of that object. To this end, we presented photographs of consistent and inconsistent objects (e.g., perfume vs. pinecone) superimposed on scenes (e.g., a bathroom) and close-ups of materials (e.g., tiles). In Experiment 1, consistent objects on scenes were named more accurately than inconsistent ones, while there was only a marginal consistency effect for objects on materials. Also, we did not find any consistency effect for scrambled materials that served as color control condition. In Experiment 2, we recorded event-related potentials and found N300/N400 responses—markers of semantic violations—for objects on inconsistent relative to consistent scenes. Critically, objects on materials triggered N300/N400 responses of similar magnitudes. Our findings show that contextual materials indeed affect object processing—even in the absence of spatial scene structure and object content—suggesting that material is one of the contextual “ingredients” driving scene context effects.

Structural Color Control of CoFeB-Coated Nanoporous Thin Films

Unlike color dyes, structural colors only slightly fade during long-term usage. Here, structural colors were controllably achieved by constructing CoFeB photonic crystal layers on the surface of a nanoporous aluminum oxide (AAO) substrate by magnetron sputtering deposition. The resulting material showed a wide visible spectral response and achieved structural color control with a high resolution, high color purity, and saturation. The angle-dependent color changes of CoFeB@AAO films were further investigated by changing the incident light angle. The simulation results of the model are consistent with the experiments, which is significant in practical applications. This strategy may have great potential applications for solid structure color coatings, anti-counterfeiting and security, information storage, and electromagnetic sensors.

Sintering-Based In-Situ Synthesis and Characterization by TEM of Noble Metal Nanoparticles for Ceramic Glaze Color Control

Gold and silver salt mixtures are incorporated in ceramic glazes for in situ development of mixtures of gold and silver nanoparticles (NPs) that subsequently allow for a wide spectrum of low metal loading color control within ceramic materials. Prior work has shown that gold NPs can be used to create vibrant, color-rich red pigments in high-temperature ceramic and glass applications, though the achievable diameter of the gold NP ultimately limits the available range of color. The current study significantly expands color control from traditional gold nanoparticle red through silver nanoparticle green via the alteration of gold-to-silver salt ratios incorporated in the glaze formulations prior to sintering. Nanoparticle-based coloring systems are tested in both oxidative and reductive firing atmospheres. While the oxidation environment is found to be prohibitive for silver NP stability, the reductive atmosphere is able to form and sustain mixtures of gold and silver NPs across a wide color spectrum. All glazes are analyzed via reflectance spectrometry for color performance and samples are characterized via TEM and EDS for composition and sizing trends. This study creates new groundwork for a color-controlled NP system based on noble metal ratio blends that are both nontoxic and achieved with radically lower metal pigment loading than traditional glazes.

Mathematical Model for Determining the Colorimetric Characteristics of Composite Materials Based on PLA and Wood Filler

The environmental concern of many countries seeking to conserve natural resources is driving the development, production and consumption of biodegradable composites. However, in view of their high cost, adding various fillers to composites (such as, wood flour (WF)) is promising. The advantages of using composites with wood fillers are resistance to weathering, environmental friendliness, ease of mechanical processing, and the possibility of waste disposal. To improve the properties and expand the scope of such composites, it is possible to use thermal modification of the filler, which gives wood such properties as: high hardness, water resistance, chemical and biological resistance. Thermal modification consists in heating wood in the temperature range from 150 to 230 °C without oxygen. At the same time, color properties of the material are changed definitely: an increase in the processing temperature affects darkening of wood, which leads to a change in the color characteristics of the last composite. In this regard, a regression mathematical model is proposed for easy color control prediction of the product, which is obtained as a result of composites color analysis based on polylactide (PLA) and the RGB color code. The proposed mathematical model, setting the processing temperature of wood filler, lets predicting the intensities of red, green and blue components for the subsequent visual representation of the last composition color using standard computer programs.

BiPOLES is an optogenetic tool developed for bidirectional dual-color control of neurons

Optogenetic manipulation of neuronal activity through excitatory and inhibitory opsins has become an indispensable experimental strategy in neuroscience research. For many applications bidirectional control of neuronal activity allowing both excitation and inhibition of the same neurons in a single experiment is desired. This requires low spectral overlap between the excitatory and inhibitory opsin, matched photocurrent amplitudes and a fixed expression ratio. Moreover, independent activation of two distinct neuronal populations with different optogenetic actuators is still challenging due to blue-light sensitivity of all opsins. Here we report BiPOLES, an optogenetic tool for potent neuronal excitation and inhibition with light of two different wavelengths. BiPOLES enables sensitive, reliable dual-color neuronal spiking and silencing with single- or two-photon excitation, optical tuning of the membrane voltage, and independent optogenetic control of two neuronal populations using a second, blue-light sensitive opsin. The utility of BiPOLES is demonstrated in worms, flies, mice and ferrets.

Optical current generation in graphene: CEP control vs. ω + 2ω control

The injection of directional currents in solids with strong optical fields has attracted tremendous attention as a route to realize ultrafast electronics based on the quantum-mechanical nature of electrons at femto- to attosecond timescales. Such currents are usually the result of an asymmetric population distribution imprinted by the temporal symmetry of the driving field. Here we compare two experimental schemes that allow control over the amplitude and direction of light-field-driven currents excited in graphene. Both schemes rely on shaping the incident laser field with one parameter only: either the carrier-envelope phase (CEP) of a single laser pulse or the relative phase between pulses oscillating at angular frequencies ω and 2ω, both for comparable laser parameters. We observe that the efficiency in generating a current via two-color-control exceeds that of CEP control by more than two orders of magnitude (7 nA vs. 18 pA), as the ω + 2ω field exhibits significantly more asymmetry in its temporal shape. We support this finding with numerical simulations that clearly show that two-color current control in graphene is superior, even down to single-cycle pulse durations. We expect our results to be relevant to experimentally access fundamental properties of any solid at ultrafast timescales, as well as for the emerging field of petahertz electronics.

The role of contextual materials in object recognition

While scene context is known to facilitate object recognition, little is known about whichcontextual “ingredients” are at the heart of this phenomenon. Here, we address the question ofwhether the materials that frequently occur in scenes (e.g., tiles in bathroom) associated withspecific objects (e.g., a perfume) are relevant for processing of that object. To this end, wepresented photographs of consistent and inconsistent objects (e.g., perfume vs. pinecone)superimposed on scenes (e.g., bathroom) and close-ups of materials (e.g., tiles). In Experiment1, consistent objects on scenes were named more accurately than inconsistent ones, while therewas only a marginal consistency effect for objects on materials. Also, we did not find anyconsistency effect for scrambled materials that served as color control condition. In Experiment2, we recorded event-related potentials (ERPs) and found N300/N400 responses – markers ofsemantic violations – for objects on inconsistent relative to consistent scenes. Critically, objectson materials triggered N300/N400 responses of similar magnitudes. Our findings show thatcontextual materials indeed affect object processing – even in the absence of spatial scenestructure and object content – suggesting that material is one of the contextual “ingredients”driving scene context effects.