Highly structured graphene polyethylene nanocomposites

This research presents an overview of the properties of highly structured, low density polyethylene-graphene nanoplatelets (LDPE-GnP). The influence of nanofiller content, size and processing conditions on the material properties have been investigated. Therefore, rheological and thermal nanocomposite properties were investigated. So-called dry-coating method has been used in order to prepare masterbatches which were thereafter extruded by means of single screw extruder resulting in a strong anisotropy in the extruded samples. Graphene nanoplatelets were oriented in the extrusion direction for all shear rates and flow histories investigated, as confirmed by scanning electron microscopy. The rheological percolation was determined via nonlinear parameters to be around 11wt%. Thermal conductivity measurements revealed strong anisotropy with in-plane conductivity increasing with GnP content

Bibliometrická analýza české geografie v databázi SCOPUS

The analysis focuses on two journals: Geografie and Moravian Geographical Reports. The analysis demonstrates that the scope of both journals is only regional, due to their relatively restricted range of authors and citations. Despite their status as premier Czech geographical periodicals, both journals serve mainly as conduits for the exchange of information among academics on a regional basis. This paper lists the most frequently cited Czech geographers and interdisciplinary citations.527

Adsorption of Phosphates from Aqueous Solutions on Alginate/Goethite Hydrogel Composite

The basic process to reduce the phosphate ions in aquatic environments is to move the phosphorus circulation processes on the water–sediment phase boundary towards depositing it in the solid phase through chemical precipitation or adsorption. Modern technologies for removal of phosphorus can be based on cheap and environmentally friendly natural polysaccharides modified with multivalent metals. In this study alginate/goethite hydrogel composite has been investigated for phosphate uptake from aqueous solutions. The composite was produced by a cross-linking reaction between sodium alginate and calcium chloride in six configurations of suspensions, which differed in goethite content. In all cases, spherical and durable capsules of alginate/goethite composite were produced. In laboratory tests, mechanical stability of the capsules at various temperatures and the coexisting ions of lake water were tested. Chemical composition of the aquatic environment had a strong influence on their mechanical stability. Static batch adsorption of phosphate studies were carried out for two adsorbents: goethite and alginate/goethite composite. The goethite gelation resulted in almost double growth of sorption capacity in the case of adsorption from deionized water and, on average, a 50% growth in adsorption from the environmental water compared to raw goethite. The alginate/goethite adsorbent removed phosphate in a wide pH spectrum—from 4 to 10. Results suggest that the proposed adsorbent has potential for the removal of phosphate from contaminated water

Gas Barrier, Thermal, Mechanical and Rheological Properties of Highly Aligned Graphene-LDPE Nanocomposites

This contribution reports on properties of low-density polyethylene-based composites filled with different amounts of graphene nanoplatelets. The studied samples were prepared in the form of films by means of the precoating technique and single screw melt-extrusion, which yields a highly ordered arrangement of graphene flakes and results in a strong anisotropy of composites morphology. The performed tests of gas permeability reveal a drastic decrease of this property with increasing filler content. A clear correlation is found between permeability and free volume fraction in the material, the latter evaluated by means of positron annihilation spectroscopy. A strong anisotropy of the thermal conductivity is also achieved and the thermal conductivity along the extrusion direction for samples filled with 7.5 wt % of GnP (graphene nanoplatelets) reached 2.2 W/m\ub7K. At the same time, when measured through a plane, a slight decrease of thermal conductivity is found. The use of GnP filler leads also to improvements of mechanical properties. The increase of Young’s modulus and tensile strength are reached as the composites become more brittle

Selected prebiotics and synbiotics administered in ovo can modify innate immunity in chicken broilers

Abstract Background A previous study showed that prebiotics and synbiotics administered in ovo into the egg air cell on the 12th day of incubation enhance the growth and development of chickens. However, the influence of this procedure on the development and efficiency of the innate immune system of broiler chickens is unclear. Therefore, the aim of this study was to evaluate whether the early (on the 12th day of embryo development) in ovo administration of selected prebiotics (inulin − Pre1 and Bi2tos − Pre2) and synbiotics (inulin + Lactococcus lactis subsp. lactis IBB SL1 − Syn1 and Bi2tos + L. lactis subsp. cremoris IBB SC1 − Syn2) influences the innate immune system. Results Chickens (broiler, Ross 308) that were treated with Pre1 exhibited a decreased H/L ratio on D7, but an increased H/L ratio was observed on D21 and D35. In the remaining experimental groups, an increase in the H/L ratio was observed on D21 and D35. The oxidative potential of leukocytes measured using the NBT test increased on D21 in Pre2 and Syn1 groups. The rate of the phagocytic ability of leukocytes increased in Pre1 and Syn1 groups on D21. The phagocytic index decreased in Pre1 and Syn2 groups on D21 and D35. Concurrently, the count of WBC in circulating blood decreased on D21 in Pre1, Pre2, and Syn1 groups. The hematocrit value was increased in Syn1 chickens on D21, in Pre1 chickens on D35, and in Syn2 chickens on both time points. Conclusions Early in ovo treatment of chicken embryos with prebiotics and synbiotics may temporarily modulate not only the production/maturation of leukocytes but also their reactivity