In contrast to conventional preforming techniques, additive manufacturing features direct and layer-by-layer fabrication, which provides viable new capabilities for the fabrication of reinforced ...composites. In this article, we explore the microstructural design as well as additive manufacturing and characterization of 3D orthogonal, short carbon fiber/acrylonitrile-butadiene-styrene (ABS) preforms and composite. First, an array of 3D orthogonal preforms is designed based on topological consideration and validated by fused filament fabrication of pure ABS wire; high fidelity between models and preforms is accomplished. Then, short carbon fibers are introduced into the designed 3D orthogonal preforms as reinforcement, using a short carbon fiber/ABS wire. Lastly, the compressive behavior of a 3D orthogonal, short carbon fiber/ABS preform and that of its silicone infused composite are characterized. The preform design methodology developed in this research as well as the preliminary effort made in composite fabrication and characterization demonstrates the feasibility of additive manufacturing of 3D orthogonal preform based fiber composites.
Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety of ...hydroxypropyl methyl cellulose and methyl cellulose as technological feed additives for all animal species. In its previous opinions on the safety and efficacy of the products, the FEEDAP Panel could not conclude on proper identification and characterisation as required for a feed additive. The occurrence of potential toxic impurities could also not be assessed. Based on the new data provided, the feed additives hydroxypropyl methyl cellulose and methyl cellulose were properly identified and characterised and were shown to meet the specifications set for the food additives. Therefore, the conclusions of the safety assessments reached in the previous opinions for hydroxypropyl methyl cellulose and methyl cellulose meeting the food additive specifications, apply to the hydroxypropyl methyl cellulose and methyl cellulose under assessment as feed additives. The additives are considered safe for all animal species, the consumer and the environment. In the absence of data, the FEEDAP Panel is not in the position to conclude on the safety for the user.
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•A 2D coupled Lattice Boltzmann-Cellular Automata (CALB) model for additive manufacturing is presented.•Powder related stochastic effects are included.•CALB model is applied to ...simulate multilayer hatching solidification of powder beds.•The model is able to reproduce main morphological aspects of competitive grain growth and grain penetration from side walls.•The phenomenon of grain boundary wiggling observed in experiments is well captured and explained by CALB model.
A 2D coupled Cellular Automaton (CA)–Lattice Boltzmann (LB) model has been developed to simulate grain structure evolution during powder–bed–based, layer by layer, additive manufacturing (AM). The presented model includes algorithms for random powder layer generation, electron beam energy absorption, evaporation, capillarity and wetting, meltpool dynamics, its temperature evolution and face centered cubic grain solidification. The model is first validated against the experimental findings of single track electron beam melting and solidification of a baseplate and then applied to simulate the grain structure produced during AM. Influence of the hatching strategy on grain structure is presented as well as stray grain formation resulting from partially molten powder particles.
In December 2016, a panel of experts in microbiology, nutrition and clinical research was convened by the International Scientific Association for Probiotics and Prebiotics to review the definition ...and scope of prebiotics. Consistent with the original embodiment of prebiotics, but aware of the latest scientific and clinical developments, the panel updated the definition of a prebiotic: a substrate that is selectively utilized by host microorganisms conferring a health benefit. This definition expands the concept of prebiotics to possibly include non-carbohydrate substances, applications to body sites other than the gastrointestinal tract, and diverse categories other than food. The requirement for selective microbiota-mediated mechanisms was retained. Beneficial health effects must be documented for a substance to be considered a prebiotic. The consensus definition applies also to prebiotics for use by animals, in which microbiota-focused strategies to maintain health and prevent disease is as relevant as for humans. Ultimately, the goal of this Consensus Statement is to engender appropriate use of the term 'prebiotic' by relevant stakeholders so that consistency and clarity can be achieved in research reports, product marketing and regulatory oversight of the category. To this end, we have reviewed several aspects of prebiotic science including its development, health benefits and legislation.
Species feeding lower at the food web like cyprinids (carp) are often advocated for sustainable aquaculture. However, their gastrointestinal biology (lack of stomach) has limited their acid‐peptic ...digestion, acid lysis of plants and invertebrate tissues, and phosphorus uptake. This review presents data from 118 articles on the use of plant‐based feed additives (PFAs) in Cyprinus carpio (common carp). Our review shows that most PFA research in carp is focused on improving feed and nutrient utilization efficiency along various levels (in vivo digestibility, metabolizability to in situ nutrient loading), while other half is focused on ensuring animal welfare standards (biomass, immunity, welfare). Several reviewed plant‐based additives however tend to do both. The PFAs include essential oils (EOs), plant‐part extracts (PPEs), medicinal plants (herbs) and spices. The effective inclusion rate of EOs is lower (0.5%–0.75%). Whereas PPEs, herbs and spices work at a generic inclusion rate of 2%–5% in carp feeds. Even at an optimum inclusion rate, there are factors controlling PFAs efficacy such as methods of preparation (reviewed). PFAs like lemon beebrush, geranium, dill, Rosemary pepper and common mallow with/without certain pre‐conditions are better to avoid in cyprinid diets. Although certain PFAs may potentially alter organoleptic qualities of carp flesh or might assist in training carp immunity, information on these aspects is limited. The review also provides a quick guide to researchers and feed companies interested in exploring the potential of PFAs in C. carpio aquaculture. Potential PFAs that could be valuable for cyprinids, but not yet explored are also listed.
The molecular structure of pyridine derivatives is critical to perovskite solar cell performance, especially stability. Most of the pyridine additives easily form complexes with perovskite. A new ...pyridine additive with a long alkyl chain substituted at its o‐position does not corrode perovskite. The stability of devices containing this additive is the highest among the investigated cells.
The paper describes a hydrothermal synthesis of one new-style inorganic modified graphene nanomaterial called magnesium silicate hydroxide/graphene (MSH/graphene) in a MgO-SiO2-graphite-H2O system, ...and reveals its tribological behaviors as additives in poly-alpha-olefin (PAO). These MSH/graphene nanocomposites consist of MSH and various forms of graphene evolved from natural microcrystalline graphite. Four-ball experiments indicate that MSH/graphene nanocomposites as additives in PAO display outstanding tribological performances and nearly eliminate wear despite a severe contact pressure of 3.91 GPa. This can be attributed to the attachment of graphene to MSH, enabling it to successfully enter the asperity clearances so as to bring into full play to graphene's extreme mechanical strength and/or forming a tribofilm consisting of nanocrystalline graphite and amorphous carbon (a-C) on the sliding surfaces.
MSH/graphene nanocomposites were hydrothermally synthetized using graphite as one of the raw materials. This type of nanocomposites consist of MSH and various forms of graphene. Display omitted
•MSH/graphene nanocomposites were hydrothermally synthesized using graphite as a raw material.•MSH/graphene consists of MSH and various types of graphene.•The slid surfaces lubricated with MSH/graphene-containing oil have infinitesimal wear under a pressure of 3.91 GPa.•Tribological tests confirm graphene competitively penetrate into the contact area and form a tribofilm.
As part of the cosmos of digital fabrication technology, Additive Manufacturing (AM) systems are able to manufacture three-dimensional components and products directly from raw material and 3D design ...data. The layer-by-layer operating process of these systems does not require the use of tools, moulds or dies.
Technology observers speculate that AM will have a profound economic impact on the manufacturing sector and indeed on wider society. By constructing a model of production cost for two different AM systems used commercially for the manufacture of end-use metal parts, Electron Beam Melting (EBM) and Direct Metal Laser Sintering (DMLS), this paper performs an inter-process comparison of cost performance. High specific costs, measured at £2.39 and £6.18 per cm3 of material deposited respectively, are identified as a central impediment to more widespread technology adoption of such additive systems.
The research demonstrates differing levels of system productivity, suggesting that the observed deposition rates are not sufficient for the adoption of EBM and DMLS in high volume manufacturing applications. Despite the absence of amortisable tooling costs, the analysis also reveals that economies of scale are achievable in AM. The results reached are further discussed in the light of the varying strategic requirements posed by the market-pull and technology-push modes of innovation which are both found in the AM industry.
•Inter-process cost study of two metallic Additive Manufacturing (AM) platforms.•Observed high manufacturing costs and large differences in machine productivity and cost.•Results indicate that economies of scale are a reality in AM.•Current machine performance may be due to the technology’s origin in prototyping.
•The addition of trace metals in form of nanoparticles reduced the lag phase.•Nanoparticles reduced time to achieve the highest biogas and methane production.•Biogas and methane production were ...proportional to nanoparticles concentration.•Nanoparticles biostimulate the methanogenic bacteria and increase their activity.
Nanoparticles (NPs) were hypothesized to enhance the anaerobic process and to accelerate the slurry digestion, which increases the biogas and methane production. The effects of NPs on biogas and methane production were investigated using a specially designed batch anaerobic system. For this purpose, a series of 2L biodigesters were manufactured and implemented to study the effects of Cobalt (Co) and Nickel (Ni) nanoparticles with different concentrations on biogas and methane production. The best results of NPs additives were determined based on the statistical analysis (Least Significant Difference using M-Stat) of biogas and methane production, which were 1mg/L Co NPs and 2mg/L Ni NPs (p<0.05). These NPs additives delivered the highest biogas and methane yields in comparison with their other concentrations (0.5, 1, and 2mg/L), their salts (CoCl2, and NiCl2) and the control. Furthermore, the addition of 1mg/L Co NPs and 2mg/L Ni NPs significantly increased the biogas volume (p<0.05) by 1.64 and 1.74 times the biogas volume produced by the control, respectively. Moreover, the aforementioned additives significantly increased the methane volume (p<0.05) by 1.86 and 2.01 times the methane volume produced by the control, respectively. The highest specific biogas and methane production were attained with 2mg/L Ni NPs (p<0.05), and were 614.5mlBiogasg−1VS and 361.6mlCH4g−1VS, respectively compared with the control which yielded only 352.6mlBiogasg−1VS and 179.6mlCH4g−1VS.