Wall Protection Research Articles

Link of Weak Ferromagnetism to Emergence of Topological Vortices in Bulk Ceramics of h-LuMnxO3 Manganite

Research on topological defects in hexagonal manganites exposed uncovered properties of topologically protected domains and domain walls. Topological defects of h-REMnO3 oxides (RE = Lu–Dy and Sc, In) modify essential multiferroic properties. Despite wide research with single crystals of stoichiometric composition, for the case of polycrystalline ceramics rare studies explored the effects of adjustment in chemical composition on phase transition temperatures, antiferromagnetic ordering, topological domain sizes, and potential modifications of the vortex density predicted by the Kibble–Zurek mechanism (KZM). The effect of cation vacancy doping of either Mn, or Lu sublattices of h-LuMnxO3, on appearance of ferroelectric vortices at the Curie point of apolar-to-polar ferroelectric ordering, TC, in bulk ceramics is investigated here. For cooling rates up to 40 K min–1 the Kibble–Zurek mechanism sets the density of FE vortices in ceramics of the LuMnxO3 system. Magnetic hysteresis loops taken from the represen...

An experimental genetically attenuated live vaccine to prevent transmission of Toxoplasma gondii by cats

Almost any warm-blooded creature can be an intermediate host for Toxoplasma gondii. However, sexual reproduction of T. gondii occurs only in felids, wherein fertilisation of haploid macrogametes by haploid microgametes, results in diploid zygotes, around which a protective wall develops, forming unsporulated oocysts. Unsporulated oocysts are shed in the faeces of cats and meiosis gives rise to haploid sporozoites within the oocysts. These, now infectious, sporulated oocysts contaminate the environment as a source of infection for people and their livestock. RNA-Seq analysis of cat enteric stages of T. gondii uncovered genes expressed uniquely in microgametes and macrogametes. A CRISPR/Cas9 strategy was used to create a T. gondii strain that exhibits defective fertilisation, decreased fecundity and generates oocysts that fail to produce sporozoites. Inoculation of cats with this engineered parasite strain totally prevented oocyst excretion following infection with wild-type T. gondii, demonstrating that this mutant is an attenuated, live, transmission-blocking vaccine.

Optimization of DEMO geometry and disruption location prediction

The design study of DEMO is one of the main points of the European Roadmap to Fusion Electricity. The present pre-conceptual design phase of DEMO is used to explore a flexible range of the main machine geometrical design parameters and plasma scenarios. This paper presents the electromagnetic (EM) modelling of the DEMO baseline scenario, including the optimization activities on the electrically conductive structures surrounding the plasma and their influence on the passive vertical stabilization (VS). The improvements on the passive and active VS allowed increasing the maximum controllable plasma elongation, with a consequent increase on the fusion performance. Finally, a study is presented on the possibility to predict the plasma final position following a vertical displacement event (VDE). This prediction capability supports the development of a wall protection strategy from plasma transients. A model is presented based on the assumptions on the characteristic time constants expected for the current quench (CQ) time and L/R time constant of the conductive structures.

Model of fragmentation distribution over a protective wall

This paper presents an analysis of perforated witness plates that were part of an experimental setup of previously published field tests. The witness plates were placed in the field tests to check the fragmentation pattern of the cased charge. A qualitative inspection of the plates shows that the spatial mass distribution of the fragments was not uniform over the wall height, and that it was characterized by an intense strip, which was stricken by a high magnitude of the fragmentation mass. Image analysis of the post-test plate pictures indicated that a previously suggested model for the intense strip geometry and fragmentation mass ratio under-predicts these parameters for increased standoff distances. Consequently, the paper presents an updated, enhanced version of the model, which considers the variation of the fragmentation Taylor angle along the charge and leads to a thicker intense strip. The updated model parameters were chosen in accordance with the analyzed experimental results and they were further verified with image analyses from additional published experimental data.The enhanced intense-strip model presented here can be used for global consideration of the fragmentation loading over a wall they strike. Furthermore, it should be emphasized that contrary to the common design approach, which assumes uniform damage and/or loading of the fragments, this model provides a useful tool for a realistic evaluation of the structural response of a protective wall, which is subjected to the combined loading of blast and fragments.

Nickel in hierarchically structured nitrogen-doped graphene for robust and promoted degradation of antibiotics

Nickel nanoparticles encapsulated in nitrogen-doped porous graphene (Ni@NPG) were synthesized through a one-pot method as a novel material for catalytic activation of persulfate (PS). The Ni@NPG catalysts were evaluated for adsorptive and catalytic removals of antibiotic sulfachloropyridazine (SCP) as an emerging pollutant and were found to exhibit excellent adsorption and catalysis with 100% SCP removal from water in only 30 min. Meanwhile, great stability and reusability can be achieved with satisfactory organic degradation after 4 successive runs. In addition, metal leaching was prohibited from the metal@carbon catalysts due to the protection of carbon walls. The influences of humid acid and inorganic anions (HCO3−, Cl−, Br− and H2PO4−) on SCP degradation at various concentrations were further investigated and the present study shows that all these species promoted the SCP degradation at a low concentration whereas an inhibition effect occurred at higher concentrations due to radical quenching. Electron paramagnetic resonance (EPR) and quenching experiments reveal the PS activation mechanism involving generation of SO4•−, •OH and •O2− without singlet oxygen. The synergistic effect of radical and nonradical pathways played crucial roles during the SCP oxidation process.

SELECTION CRITERIA FOR FUSION REACTOR STRUCTURES

Fusion energy is the ultimate energy to cover Mankind’s energy needs forever. However, taming the fusion energy is the greatest technological challenge the humanity is facing. Development of structural materials to withstand against the extreme conditions in the course of fusion power plant operation is one of the toughest nuts to be cracked. A great number of structural materials have been investigated for fusion reactor applications, such as steels (austenitic stainless steels and ferritic/martensitic steels), vanadium alloys, refractory metals and alloys (niobium alloys, tantalum alloys, chromium and chromium alloys, molybdenum alloys, tungsten and tungsten alloys), and composites (SiCf/SiC and Carbon Fibre Composite CFC composites). Steels have extensive technological data base and significantly lower cost compared to other refractory metals and alloys. Ferritic steels and modified austenitic stainless (Ni and Mo free) have relatively low residual radioactivity. However, steels cannot withstand high neutron wall loads to build an economically competitive fusion reactor. Some refractory metals and alloys (niobium alloys, tantalum alloys, molybdenum alloys, tungsten and tungsten alloys) can withstand high neutron wall loads. But, in addition to their very limited technological data base, they have high residual radioactivity and prohibitively high production costs. A protective, flowing liquid zone to protect the first wall of a fusion reactor from direct exposure to the fusion reaction products could extend the lifetime of the first wall to the expected lifetime of the fusion reactor. In that context, a fusion-fission (hybrid) with a multi-layered spherical blanket has been investigated, which is composed of a first wall made of oxide dispersed steel (ODS, 2 cm); neutron multiplier and coolant zone made of LiPb; ODS-separator (2 cm); a molten salt FLIBE coolant and fission zone; ODS-separator (2 cm); graphite reflector. Calculations are conducted for a liquid wall with variable thickness, containing Flibe + heavy metal salt (UF4 or ThF4) is used for first wall protection. The content of heavy metal salt is chosen as 4 and 12 mol%. A flowing wall with a thickness of ~ 60 cm can extend the lifetime of the solid first wall structure to a plant lifetime of 30 years for 9Cr–2WVTa and V–4Cr–4Ti, whereas the SiCf/SiC composite as first wall needs a flowing wall with a thickness of ~ 85 cm to maintain the radiation damage limit.

Critical design issues in DEMO and solution strategies

The EU fusion roadmap defines as a goal the development of a DEMO, which achieves a long plasma operation time and demonstrates tritium self-sufficiency and net electricity output. Eight design issues have been identified as critical: (i) feasibility of wall protection limiters during plasma transients, (ii) integrated design of breeding blanket and ancillary systems, (iii) power exhaust taking advantage of advanced divertor configurations, (iv) tokamak architecture based on vertical blanket segments, (v) direct or indirect power conversion concept, (vi) configuration of plant systems in the tokamak building, (vii) feasibility of hydrogen separation in the torus vacuum pump and direct recirculation, and (viii) plasma scenario.For each of these issues potential solutions have been identified and activity plans have been defined for the associated developments and assessments. Two of these affect in particular the integrated design of the DEMO machine, namely (i) and (iv). These are introduced and discussed in this article providing a summary of identified risks, requirements, and solution concepts. For the remaining six design issues references are provided only due to space limitations in this article.

Experimental Study and Numerical Simulation of Dynamic Stress‐Strain of Directional Blasting with Water Jet Assistance

Effective control of the explosive energy and the propagation direction of blast‐induced crack and minimizing damage of remaining rock mass are the main purposes of directional‐controlled blasting. In this paper, the experimental test on blast strain fields affected by water jet slot and blasthole wall protection material is conducted. Next, the FEM software ANSYS/LSDYNA is used to simulate the blast‐induced crack propagation and the blast stress wave transmission of different types of blasthole, and the distribution and evolution law of dynamic blast stress are also analyzed. The results indicate that the existence of blasthole wall protection material is not only beneficial to the “guiding effect” of blast‐induced crack propagation of water jet slot but also beneficial to reduce blast‐induced damage of remaining rock mass. Besides, the bigger Dm/rb is, the weaker the “guiding effect” and “blasthole wall protection effect” by water jet slot and wall protection material are.

Reduction of stress concentration by polymer flexible joints in seismic protection of masonry infill walls in RC frames

In the paper, the phenomenon of stress concentration occurring in brittle structural materials of infill structures is discussed. Four innovative repair methods based on flexible joints made of polyurethane PM are presented. They provide a reduction of the stress concentration and improvethe structural ductility. The effectiveness of newly proposed timber-polyurethane dissipative struts is proved by laboratory shear tests, which results are discussed in detail. The calculated dissipation energy and stiffness of the proposed system ensures a simultaneous transfer of loads and large deformations occurring during an earthquake to the introduced dissipative struts and improves the system safety. The recommended repair methods can be used efficiently by emergency teams in seismic areas.

Energy efficient renovation of typical buildings in the subtropics

The field of study is the experimentally justified choice of material for a single-layer, energy-efficient thermal protection of the exterior walls of typical buildings in the subtropics. A decrease in the vapor permeability of the mineral heat insulation at a humidity of more than 50% has been experimentally confirmed, and their loss of heat-shielding properties during moistening has been substantiated. It is recommended to correct the vapor permeability values of external walls with multilayer heat protection with Rockwool due to a decrease in the diffusion resistance coefficient of the wet zone of the material compared to the dry zone. Based on a comparative analysis of the design parameters of the types of thermal protection, it is recommended to use thermal plasters as single-layer thermal insulation systems. The experimentally established value of open porosity of 83.1%, for thermo-plaster based on foam glass, made it possible to choose protection against moisture in the form of penetrating Penetron waterproofing. The use of such protection reduced the value of open porosity of samples to 59.2% and eliminated the effect of condensate on energy efficiency when modernizing existing buildings.

Efficiency of blast walls for protection of soft targets

Abstract The recent trend of terrorist attacks on civilian targets, including transportation systems, resulted in efforts to harden and strengthen these objects which previously were not designed to cope with this kind of threat. The blast mitigation strategies traditionally used in industrial facilities may provide an additional safety. One such solution is a blast wall that could be used for facade systems or for protection of muster areas and evacuation routes of metro and train stations or airports. This paper deals with the assessment of the blast response of protection walls. The typical types of blast walls commonly used in practice in industrial sector are described. The behavior of blast walls is characterized using simple analytical approach and finite element modelling. The advantages and limitations related to each of these characterization techniques are discussed compared with findings of other authors. Furthermore, a parametric study is performed through extrapolation of numerical models. Two common types of panels with both fixed and pinned boundary conditions are subjected to directly defined pressure loads. Their responses are compared in order to evaluate the effects on the primary steelwork. Possible benefits deriving from typological and geometrical modifications of the local element are also presented. Particular emphasis is given to the importance of the estimation of the reaction forces, displacements and energy dissipation.

Efforts to Improve the Durability of Concrete Protective Walls in the New Tomei Expressway (Atsugi Minami IC - Gotenba JCT)

Efforts to Improve the Durability of Concrete Protective Walls in the New Tomei Expressway (Atsugi Minami IC - Gotenba JCT)

MECHANISM OF PROTECTIVE PROPERTIES OF POLYURETHANE AND COMPOSITIONS ON THE BASIS OF LIQUID GLASS AGAINST ELETRIC AND VIBRATIONAL EFFECTS

It is assumed that the reason for the acceleration and amplification of the vibration and noise of ordinary tram tracks in recent years and decades is their high wear due to the lack of funds for their maintenance. However, the research of the authors of the article showed that the main reason for the gatherings and accidents is the excess negative charge of the Earth. The aim of the study is to reveal the mechanism of the protective properties of materials, in particular polyurethane and the liquid-glass composition (LGC), and their application to protect the tram tracks in conditions of high excess negative charge of the Earth. For this purpose, analytical and full-scale research methods are used, based on the principles and laws of Macrocolloid chemistry and Physico-chemical mechanics. For the construction of new tram tracks in big cities, huge reinforced concrete slab or monolithic bases combined with road ways are used. This led to an even greater accumulation of excess negative charge of the Earth under the combined tracks and houses, to the emergence of previously virtually absent ground dips under the tracks, to an increase in accidents with serious consequences. Polyurethanes recommended for use have not only higher vibration-damping properties, but also are protective against excessive negative charges of the Earth. The liquid-glass composition (LGC) has the same properties. These protective functions are due to active -С=О groups in polyurethane and -S=О groups in a liquid-glass composition. They have a double bond and high electronegativity, as well as very large dipole moments. Methods have been developed to protect materials and structures of the tram tracks and nearby houses from the excessive negative charge of the Earth with the help of protective screens and walls, as well as high-performance fastening SRS-T.

Fence-Wall diplomacy is a factor for boundary security

The recent decades have witnessed sweeping changes in the modern global policy and international relations: some countries reinforce their geopolitical positions and economic capacity, while others lose their leading role. However, all states are united in their endeavor to use new mechanisms in asserting their foreign policy issues or make use of the tools that have been developed by some countries through centuries. One of the popular tools to ensure security of the state borders which have been on great demand in the last several decades is building of protective structures on the borders between countries. And about 50 countries have already obtained certain experience in this area applying high technologies and most advanced engineering solutions in implementation of such projects. Such changed approaches to pursuance of foreign policy objectives may be associated with diffusion movement of people caused by military, political and ethnoreligious conflicts, food shortage, climate changes, growing terrorism, crime, corruption, etc. The driving motive here was and still remains the protection of national security and economic interests, curbing the illegal migration, supply of arms and drugs, transboundary terrorism. Construction of protective walls, barriers and fences reflects the level of political relationships among the countries and the level of their economic capabilities with the help of which the states are seeking to stop completely, to revise or drastically restrict bilateral relations. It is not an easy task to assess efficiency of the constructed walls and barriers, and the more so in the face of complex issues existing in bilateral relations. The experience of some countries in implementation of major protection-and-defense projects has shown that they succeed in decreasing the illegal migrant flow, penetration of terrorists, arresting the arms and drugs circulation. However, in general, these efforts within the frame of bilateral relations are a hindrance to development of cooperation between the states reflecting at the same time their inability to settle the arising contradictions on the basis of the international law.

Reprint of "Ion beam sputter coating in combination with sol-gel dip coating of Al alloy tube inner walls for corrosion and biological protection"

Aluminium alloy AlCuMg is an alloy with high mechanical strength and fracture toughness, but it suffers from poor corrosion resistance and friction behaviour. With a combined process of sol-gel deposition of zirconium oxide and a top coating of diamond-like carbon formed by ion beam sputtering with a movable conical sputter target inside the tube, the inner walls of AlMgCu tubes were homogeneously coated with a duplex coating with high resistance against corrosion in chloride solution. When Ag was added to the carbon sputter target, a DLC coating that contained Ag was obtained. Microbial tests showed that the coating is effective against pathogenic E. coli bacteria.

Observation of a topologically protected state in a magnetic domain wall stabilized by a ferromagnetic chemical barrier

The precise control and stabilization of magnetic domain walls is key for the development of the next generation magnetic nano-devices. Among the multitude of magnetic configurations of a magnetic domain wall, topologically protected states are of particular interest due to their intrinsic stability. In this work, using XMCD-PEEM, we have observed a topologically protected magnetic domain wall in a ferromagnetic cylindrical nanowire. Its structure is stabilized by periodic sharp alterations of the chemical composition in the nanowire. The large stability of this topologically protected domain wall contrasts with the mobility of other non-protected and non-chiral states also present in the same nanowire. The micromagnetic simulations show the structure and the conditions required to find the topologically protected state. These results are relevant for the design of future spintronic devices such as domain wall based RF oscillators or magnetic memories.

Influence of spray drying on the stability of food-grade solid lipid nanoparticles

This study investigated spray drying of food-grade solid lipid particles (SLN) and nanostructured lipid carriers (NLC) containing ω-3 fish oil. Stable SLN and NLC dispersions with tristearin as carrier lipid were formed by using a combination of Quillaja saponins and high-melting lecithin as emulsifiers. Our specific goal was to study the influence of four different spray drying inlet and outlet temperatures (Tinlet/outlet = 140–170 °C/65–95 °C) and two different maltodextrin types (DE 6 and DE 21) with different molecular weights as protective wall materials on the physical and polymorphic stability of the solid lipid particles. The results revealed that the low molecular weight maltodextrin DE 21 was a superior wall material in stabilizing the solid lipid particles. Moreover, the lipid particles spray dried at Tinlet/outlet of 140/65 °C exhibited the highest physical and polymorphic stability, whereas using higher Tinlet/outlet led to bigger particles which were more prone to polymorphic transition. This was also verified in a 71-day storage test. The findings were explained that by preventing the melting of the tristearin carrier lipid during spray drying, the crystallized lipid particles remained intact inside the amorphous maltodextrin layer and exhibited high physical and polymorphic stability. These findings are important for generating stable food-grade spray dried powders.

Microencapsulation of Lactic Acid Bacteria Improves the Gastrointestinal Delivery and in situ Expression of Recombinant Fluorescent Protein.

The microencapsulation process of bacteria has been used for many years, mainly in the food industry and, among the different matrixes used, sodium alginate stands out. This matrix forms a protective wall around the encapsulated bacterial culture, increasing its viability and protecting against environmental adversities, such as low pH, for example. The aim of the present study was to evaluate both in vitro and in vivo, the capacity of the encapsulation process to maintain viable lactic acid bacteria (LAB) strains for a longer period of time and to verify if they are able to reach further regions of mouse intestine. For this purpose, a recombinant strain of LAB (L. lactis ssp. cremoris MG1363) carrying the pExu vector encoding the fluorescence protein mCherry [L. lactis MG1363 (pExu:mCherry)] was constructed. The pExu was designed by our group and acts as a vector for DNA vaccines, enabling the host cell to produce the protein of interest. The functionality of the pExu:mCherry vector, was demonstrated in vitro by fluorescence microscopy and flow cytometry after transfection of eukaryotic cells. After this confirmation, the recombinant strain was submitted to encapsulation protocol with sodium alginate (1%). Non-encapsulated, as well as encapsulated strains were orally administered to C57BL/6 mice and the expression of mCherry protein was evaluated at different times (0–168 h) in different bowel portions. Confocal microscopy showed that the expression of mCherry was higher in animals who received the encapsulated strain in all portions of intestine analyzed. These results were confirmed by qRT-PCR assay. Therefore, this is the first study comparing encapsulated and non-encapsulated L. lactis bacteria for mucosal DNA delivery applications. Our results showed that the microencapsulation process is an effective method to improve DNA delivery, ensuring a greater number of viable bacteria are able to reach different sections of the bowel.

Infrared imaging systems for wall protection in the W7-X stellarator (invited).

Wendelstein 7-X aims at quasi-steady state operation with up to 10 MW of heating power for 30 min. Power exhaust will be handled predominantly via 10 actively water cooled CFC (carbon-fiber-reinforced carbon) based divertor units designed to withstand power loads of 10 MW/m2 locally in steady state. If local loads exceed this value, a risk of local delamination of the CFC and failure of entire divertor modules arises. Infrared endoscopes to monitor all main plasma facing components are being prepared, and near real time software tools are under development to identify areas of excessive temperature rise, to distinguish them from non-critical events, and to trigger alarms. Tests with different cameras were made in the recent campaign. Long pulse operation enforces additional diagnostic design constraints: for example, the optics need to be thermally decoupled from the endoscope housing. In the upcoming experimental campaign, a graphite scraper element, in front of the island divertor throat, will be tested as a possible means to protect the divertor pumping gap edges during the transient discharge evolution.

Emergence of Enhanced Quality Expectations in Pharmaceuticals

Commercial viability of any drug product may often bring pain for patients who otherwise wait for their drug to improve their quality of life and breath. Dryness of drug products like thyroxin, warfarin, phenobarbitone, salbutamol inhalers, morphine etc. from the market leave patient on the mercy of nature. The heart wrenching healthcare professional burst out when lifesaving drugs are not available due to any reason. Voice of civil society rises in community where care of others is felt as a moral responsibility beside capitalism and/or socialism. It is also observed and quite possible that quality defects may create similar situations of drug shortage. Manufacturing facility or its control may go out unwittingly due to knowledge limitation. A quality defect that impacts delivery and performance of drug and/or carries harmful potential has always been a matter of top priority. In both cases, ability to detect, report and assess defines presence and thickness of protection wall for the public. Power to predict uncertainty and taking measures well in time is a challenge for industry and regulators to maintain uninterrupted supply of quality drugs.