Few-Layers Graphene-Based Cement Mortars: Production Process and Mechanical Properties

Cement is the most-used construction material worldwide. Research for sustainable cement production has focused on including nanomaterials as additives to enhance cement performance (strength and durability) in recent decades. In this concern, graphene is considered one of the most promising additives for cement composites. Here, we propose a novel technique for producing few-layer graphene (FLG) that can fulfil the material demand for the construction industry. We produced specimens with different FLG loadings (from 0.05% to 1% by weight of cement) and curing processes (water and saturated air). The addition of FLG at 0.10% by weight of cement improved the flexural strength by 24% compared to the reference (bare) sample. Similarly, a 0.15% FLG loading by weight of cement led to an improvement in compressive strength of 29% compared to the reference specimen. The FLG flakes produced by our proposed methodology can open the door to their full exploitation in several cement mortar applications, such as cementitious composites with high durability, mechanical performance and high electrical conductivity for electrothermal applications.

Exploration and morphologic variation of Iris wild species with ornamental potential

Nowadays, the flower industry is growing so fast that its development requires introducing new varieties to the flower market. Iran is the habitat of numerous species of wild plants that are among the valuable genetics in the breeding process. The identification of native Iris species, investigation of morphological diversity, and distribution method have a significant effect on the introduction of this flower as new and superior cultivars cut flower and bedding plant. The documentation of the most important habitats of Iris in Arak province, identification of morphological characteristics and correlation determination of morphological traits are the most important aims of this research. The results showed that there is a correlation between some of the traits. The highest positive correlation was related to the height of flower and length of the leaf, length of the flowering stem and the length of the leaf and the height of the flower and the length of the flowering stem. The ecotypes of Iris sp. were divided into six groups. Based on the results of the cluster diagram, the bulbous species were separated from rhizome species. Generally, due to the color diversity of Iris sp. and unique beauty of the flowers and the resistance of the native species, they can be used as native foundations. Due to the prominent traits such as high durability of Iris meda, odor of I. hymernospatha Subsp. leptoneura and color diversity of I. persica, I. songarica and height of I. spuria, they can be used to introduce new ornamental species. Iris spuria is the most suitable genotype because of the high height, large flower, high durability, and beautiful flower.

High Effective Sensitivity, Wide Working Range of Melt-blown Nonwoven Conductive Substrates for Smart Wearable Strain Sensors

High sensitivity, wide working range and flexible portability of strain sensors are crucial for smart wearable applications. To obtain these performances, several elastic melt-blown nonwoven substrates with excellent flexibility and high conductivity were developed by loading with polypyrrole through a double-dipping and double-rolling finishing method. The structure and conductivity are characterized by scanning electron microscope, infrared spectrometer, digital source meter and so on. The results indicate that the conductivity of prepared substrates is affected by the pyrrole concentration and polypyrrole amount deposited in nonwovens. Obviously, the conductivity and sensitivity of substrates as strain sensors are highly and positively correlated to the fiber orientation in nonwovens, and the effective working range and corresponding sensitivity of sensors are determined by the elastic deformation interval of melt-blown substrate. When the pyrrole concentration is 5.5%, the nonwoven substrate with 45.30% porosity possesses the anisotropic optimal conductivity with 23.491 S m-1 along winding direction and 15.063 S m-1 along width direction. Moreover, the as-prepared flexible conductive substrate exhibits the characteristics of wide working strain range (0-24.2%), high sensitivity with 1.94 gauge factor at the range, fast response (0.023 s), tiny hysteresis (0.011s), high durability and stability after 1000 cycles. Furthermore, the as-prepared sensor provides an effective method to prepare smart wearable strain sensors used as the monitor of finger bending in details and the precise recognition of human voice changes.

Prospective varieties of dahlia cultural (Dahlia x cultorum Thorsr. et Reis.) when growing for shearing in conditions of protected ground

Relevance. In terms of the richness of colors, shapes and sizes of inflorescences and relative unpretentiousness during cultivation, as well as the duration of flowering of a dahlia, the cultural has no equal. Basically, this flower crop is grown in the open field and used for landscaping areas. Dahlias, due to their decorative properties, are a promising crop for cutting. But the growth in the volume of industrial cultivation of cut dahlias has long been constrained by two negative factors - the low life expectancy of cut flowers, and the fact that not all varieties of cultivated dahlias are suitable for cultivation in greenhouses. Therefore, the search for varieties that meet the aforementioned properties is an especially urgent task.Material and methods. The material for the study was 10 varieties of Dahlia × cultorum Dutch selection. They belong to different groups of dahlias – spherical: Souvenir d'Eté, The Voice, Jowey Winnie; decorative – Orion, Café au Lait, Fleurel, Karma Choc and pompom dahlias: Little William, Cornel Bronze, Petra's Wedding, All tubers were planted in phytotron beds. Phenological observations of plants were carried out according to the Methodology of State Variety Testing of Ornamental Crops. During the growing season, the following indicators were determined: the onset of phenological phases of development, the dynamics of plant growth, the number and size of inflorescences, the length of the peduncle, the duration of flowering.Results. It was found that all the studied varieties of cultural dahlias have a high decorative effect and are suitable for growing for cutting in greenhouse conditions. Growing plants in a phytotron allows you to get a high-quality cut almost two months ahead of time, as well as have a longer and more abundant flowering. It was found that the Café au Lait cultivar is not entirely suitable for cut cultivation in greenhouses or requires the development of cultivation technology that is individual for this cultivar. It was found that the Fleurel variety surpasses other studied varieties in terms of decorativeness, inflorescence size, peduncle length, onset time and flowering duration. A significant disadvantage of the variety is its high growth and fragility of the peduncles. The most popular cut varieties were Fleurel, Petra's Wedding, Jowey Winnie and Little William. It was found that the studied varieties of cultural dahlias were distinguished not only by high decorativeness, but also by high durability in a vase from 5 to 7 days.

Antibiocorrosive Hybrid Materials with High Durability

We have developed novel antibiocorrosive multifunctional hybrid materials based on functionalizedperfluoroalkylmethacrylate copolymerswith epoxy groups in main chainsand selected biologically active compounds.The hybrids are transparent, showgood adhesion to various surfaces (plastic, wood),high viscoelastic recovery in scratch testing,low wear rates and glass transitions above 323 K. No phase separation is seen in scanning electron micrography. Enhanced mechanical strength and good abrasion resistance are advantages for uses of our protective and antibiocorrosive coatings in various applications including protection of cultural heritage.

Protonic Ceramic Fuel Cell with Bi-Layered Structure of BaZr0.1Ce0.7Y0.1Yb0.1O3–δ Functional Interlayer and BaZr0.8Yb0.2O3–δ Electrolyte

Widespread application of PCFCs will require higher performance even at lower temperatures (<600 °C). This paper reports development of a protonic ceramic fuel cell (PCFC) with a bi-layered proton-conducting phase structure consisting of a BaZr0.1Ce0.7Y0.1Yb0.1O3–δ (BZCYYb1711) functional interlayer and BaZr0.8Yb0.2O3–δ (BZYb20) electrolyte. In this PCFC, a zirconate-based oxide with high durability against CO2, BZYb20, is selected as the electrolyte material, and a BZCYYb1711 functional interlayer is applied between the dense BZYb20 electrolyte and a cathode to achieve higher power density and higher open-circuit voltage (OCV) of the PCFC. In cell fabrication via conventional wet process and co-sintering, although Ni diffusion occurs from NiO-BZYb20 anode into the approximately 8-µm-thick BZYb20 electrolyte, almost no Ni diffuses into the BZCYYb1711 functional interlayer. Compared to a PCFC without this functional interlayer, the proposed PCFC exhibits higher electrochemical performance. Results showed that the BZCYYb1711 functional interlayer reduces cathode polarization resistance and increase power density of the PCFC. Moreover, the OCV increases because the BZCYYb1711 functional interlayer suppresses the current leakage caused by hole conduction of the BZYb20 electrolyte. In conclusion, this bi-layered structure effectively improves both the power density and OCV of PCFCs.