Reasonable Strength Research Articles

Fermi arcs and pseudogap phase in a minimal microscopic model of d -wave superconductivity

We show conclusively that a pseudogap state can arise at $T > T_c$, for reasonable pairing interaction strength, from order parameter fluctuations in a two dimensional minimal model of $d$-wave superconductivity. The occurrence of the pseudogap requires neither strong correlation nor the presence of competing order. We study a model with attractive nearest neighbor interaction and establish our result using a combination of cluster based Monte Carlo for the order parameter field and a twisted-boundary scheme to compute the momentum-resolved spectral function. Apart from a dip in the density of states that characterizes the pseudogap, the momentum and frequency resolution on our effective lattice size $\sim 160 \times 160$ allows two major conclusions: (i)~at $T < T_c$, despite the presence of thermal phase fluctuations the superconductor has only nodal Fermi points while all non nodal points on the normal state Fermi surface show a two peak spectral function with a dip at $\omega =0$, and (ii)~for $T > T_c$ the Fermi points develops into arcs, characterized by a single quasiparticle peak, and the arcs connect up to recover the normal state Fermi surface at a temperature $T^* > T_c$. We show the variation of $T_c$ and $T^*$ with coupling strength and provide detailed spectral results at a coupling where $T^* \sim 1.5T_c$.

Performance of an underground structure seismic mitigation system improved by frictional deformation absorbing braces

Earthquake-induced failure of underground structures attributes to their insufficient horizontal deformation capacity, which is mainly controlled by the horizontal deformation capacity of central columns. Therefore, the developed measures to update the seismic performance of underground structures are either to enhance the deformation capacity of central columns or to decrease seismic loads transmitted to columns. This paper presented an underground structure seismic mitigation system to reduce the earthquake-induced damage of underground structures by decreasing the horizontal deformation imposed on structures. In this system, frictional deformation absorbing braces are set between underground structure and earth retaining structure. The axial deformation of the braces is capable to decrease the earthquake-induced horizontal deformation of the overall structure. Furthermore, axial force of the braces can help the earth retaining structure to resist the earthquake-induced soil pressure. The deformation behaviour of the frictional deformation absorbing brace under axial loads was experimental firstly studied. Experimental results presented that the brace had a stable deformation property and could provide expected braced force. Then seismic response of the underground structure seismic mitigation system was simulated. Numerical results presented that the seismic behaviour of underground structure was sharply improved and the structure experienced very small damage even under strong earthquakes. Finally, the stiffness and strength of braces influencing the seismic performance of underground structure were discussed detailedly. The reasonable stiffness and strength of the braces for the target structure were suggested.

Preparation and characterization of Silk/Bamboo/Glass nano polymer composites

Composite materials play a vital role in today’s manufacturing world due to their light weight and reasonable strength. The selection of materials for composite manufacturing is a challenging issue. In order to overcome the weaknesses of particular characteristics of a fiber several fibers are hybridised and composites are manufactured. This paper addresses the development of hybrid composites using silk, bamboo, and glass fibers. Micro and nano fillers are added to increase the strength of the specimen. The mechanical characterization of the developed composites was evaluated through tensile testing. Microstructure studies were done on the tensile specimen. The developed composite can be recommended for structural, interior, and outdoor applications in the automobile and aircraft sectors.

Effect of Reading Activities on Children's Mental Health under the Environment of Artificial Intelligence and Deep Learning.

The illustrations in picture books are lovely and emotional; pictures and text work together to express a theme and weave into one another to create a seamless and comprehensive visual image in picture books. Reading helps children improve for life and is an unending source of wealth in one's life. Picture book reading has a positive effect on children's psychological well-being since it allows them to develop different intelligences and their spiritual worlds in addition to reading stories and learning facts. This thesis investigates, against the backdrop of artificial intelligence (AI) and deep learning, the impact of reading activities on children's psychological health. Deep learning and AI are the tools used where students can engage in a more in-depth conversation with the article and comprehend the author's mindset and background after completing the basic reading. This can help students' analytical, thinking, writing, and other application skills, as well as give them the opportunity to learn from and build upon their first reading accumulation. Research has shown that this method produces impressive results, and it is suited for widespread use because its reasonable strength has improved by 17.24% when compared to the conventional method.

Response surface methodology approach for optimized compressive strength of some mix design concrete aggregates from waste cockle shells and glass powder

Nowadays, with increased demand for aggregates for concrete and an awareness of the need of protecting natural resources, experts are becoming increasingly interested in waste material as a building material substitute. However, the compressive strength is influenced by the composition of concrete. In this study, the compressive strength of concrete under substitution using waste from cockle shells and glass was investigated using Response Surface Methodology (RSM). Central Composite Design (CCD) based on RSM was used to assess the influence of epoxy resin, cockle shells powder, and glass powder on compressive strength responses. RSM developed first-order and second-order mathematical models with findings from experimental design. Analysis of variance was used to determine the correctness of CCD's mathematical models. Desirability analysis was then employed to optimize epoxy resin, cockle shells powder, and glass powder yielding maximum compressive strength. The RSM analysis revealed that the empirical results fit well into linear and quadratic models of concrete compressive strength. The mixing components will produce cement with compressive strength in each formulation of 54.71 MPa (4.88% epoxy resin and 4.0% cockle shells powder), 47.82 MPa (6.85% epoxy resin and 8.0% glass powder), 147.0 MPa, (4% cockle shells powder and 8% glass powder), and 56.08 MPa (4.4% epoxy resin, 4.0% cockle shells powder, and 8.0% glass powder). The results confirmed that a reasonable compressive strength of concrete could be achieved using epoxy resin, cockle shells powder, and glass powder.

Design, fabrication, and characterization of distinguished lightweight and sustainable building materials

As one of the eco-friendly building materials, autoclaved aerated concrete (AAC) has received considerable attention in industrial and academic research groups over the last few years. Herein, new AAC composites with different ratios of fine sand, lime, cement, and gypsum plaster were prepared in an autoclave at a pressure of 10 bar for 8 h. The effects of adding a polymelamine sulfonate (PMS) superplasticizer to the prepared AAC composites on workability were investigated according to their physical and mechanical properties. The binding phase of calcium silicate hydrate was fully characterized via Fourier transform infrared (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The effect of AAC slurry foaming agent and water to solid ratio (W/S) was reported in detail. Furthermore, we studied the effect of ultrafine sand (<63 μm) reinforcement on the properties of AAC products.Under the specified curing conditions, the results showed that a strength value of 3.8 MPa with a low bulk density of 0.60 g/cm3 (600 kg/m3) was obtained from an AAC composite with 65 wt% fine sand, 15 wt% lime, 15 wt% cement, and 5 wt% gypsum plasters, containing 0.12 wt% Al powder and 45% water to solid ratio (W/S) mixtures. The strength value of the AAC composite can increase to 4.8 MPa, maintaining a low bulk density of 0.60 g/cm3 when the AAC slurry composite included 1% PMS at a W/S of 56% and 0.08% Al powder. In particular, the production of ultra low-density building materials can be efficiently controlled by mixing superplasticized AAC slurries with 0.16 wt% Al powder (at W/S = 56%), reaching a low bulk density of 0.39 g/cm3 (390 kg/m3) with a reasonable strength of 1.70 MPa for AAC samples. Interestingly, 50 wt% of fine sand with a particle size of about 90 μm is sufficient for tobermorite formation from the sand-lime reaction at designated hydrothermal conditions. However, replacing the large particles with ultrafine sand (<63μ) reduced the AAC strength characteristics. Besides, the compressive strength was improved by forming long tobermorite needles, lath structures, or both. In contrast, the gel-like material (poorly crystallized tobermorite) provides the lowest strength properties for AAC (about 3 MPa).

Laboratory investigation on the effect of polypropylene and nylon fiber on silt stabilized clay

A series of laboratory Investigations were performed on specimens of different proportions of Bentonite clay and silt to evaluate how the different proportions of Bentonite clay and silt vary the strength of the soil mix, with and without reinforcement, thereby to measure the corresponding changes in the strength and stress–strain properties. In this investigation Bentonite clay was treated as expansive soil and silt was treated as a primary stabilization agent. Series of investigations were performed to determine the effect of primary stabilizer silt, Polypropylene and Nylon Fiber on the Liquid Limit, Plastic Limit, Plasticity Index, Optimum moisture content, Maximum Dry Density, and Unconfined Compressive Strength of the Bentonite. The effect of different mixtures of the specimen was found to be important for the mix compacted at Optimum moisture content. While no clear threshold has been identified for different proportions of the mixture, the data indicate that increment to the percentage up to 20 percent of silt in clay produces the reasonable strength (UCS) to the mixture. Laboratory investigation results show that the effect of reinforcement with synthetic type fibers (like Polypropylene and Nylon Fiber) in the soil mixture having silt produce further complementary changes in strength and consistency limits.

Effect of hierarchical multimodal microstructure evolution on tensile properties and fracture toughness of rapidly solidified Mg–Zn–Y–Al alloys with LPSO phase

High fracture toughness Mg96.75Zn0.85Y2.05Al0.35 alloys featuring a multimodal microstructure were developed by rapidly solidified (RS) ribbon-consolidation processing. A non-heat-treated alloy that was prepared by consolidating the as-quenched ribbons exhibited a high tensile yield strength of ∼500 MPa, an elongation of ∼5%, and a plane-strain fracture toughness (KIc) of ∼9.5 MPa m1/2. Microstructure of the non-heat-treated alloy consists of two matrices: coarse-worked grains with a high kernel average misorientation (KAM) (group 1) and ultra-fine dynamically recrystallized (DRXed) grains with an intermediate KAM (group 2). The formation of ultra-fine DRXed grains with the precipitation of fine LPSO phase strengthens the alloy, but causes work-softening. The heat-treated alloy that was prepared by consolidating the RS ribbons heat-treated at 738 K exhibited a good balance of a high KIc (∼15 MPa m1/2), a reasonable yield strength (∼400 MPa), and a large elongation (∼12%) with a positive work-hardening rate. The optimized pre-consolidation heat-treatment produces multimodal microstructure having three matrices; a third group of the fine DRXed grains with a low KAM was formed in addition to groups 1 and 2. The formation of hierarchical multimodal structure in the grain size and KAM evokes strain-hardening, which has a positive effect on the fracture toughness.

Highly conductive and alkaline stable partially fluorinated anion exchange membranes for alkaline fuel cells: Effect of ammonium head groups

The effect of ammonium structure on partially fluorinated anion exchange membranes was investigated for alkaline fuel cell applications. Precursor copolymers tethered with bromopropyl side chains (PAF-C3-Br) were successfully synthesized and quaternized quantitatively with amines to obtain a series of QPAF-C3-XY membranes containing various ammonium head groups. The head groups (XY) included dimethylbutyl (DMB), dimethylhexyl (DMH), dibutylmethyl (DB), and heterocyclic N-methylpiperidinium (Pip). All of the membranes exhibited well-developed phase-separated morphology regardless of the size of the head groups as confirmed by TEM images. DFT calculations suggested that the hydrophilic domain sizes (determined from TEM images) were dependent on the polar surface area (PSA) rather than the molecular volume of the head groups. Among the membranes, QPAF-C3-Pip possessed the most balanced properties of high conductivity, low water absorbability, reasonable mechanical strength, and alkaline stability. QPAF-C3-Pip membrane (IEC = 1.26 meq/g) achieved 232 mW/m2 of the maximum power density in alkaline fuel cell, which was slightly higher than that of our previous QPAF-C3-TMA with typical trimethyl ammonium head groups (224 mW/cm2). In the durability test for 240 h, the voltage decreased from 0.74 V to 0.43 V with average decay of 1.29 mV/h. The post-durability NMR analysis revealed that the majority of the voltage loss was related to the catalyst layers.

Mechanical properties, drying shrinkage and structural performance of coconut shell lightweight concrete

The main concerns of civil engineering officials and researchers is to produce the structural lightweight concrete, which is cost effective, sustainable, durable and can behave satisfactorily under structural applications. Therefore, the use of industrial waste as an alternative lightweight aggregate (LWA) to build eco-friendly stable structures that have many realistic and financial benefits. Coconut shell (CS) is a waste industrial by-product and was successfully utilized to produce reasonable strength lightweight aggregate concrete. Four different types of concrete mix were developed with first three samples having 0%, 50%, 100% replacement of NWA with coarse CS, however, in fourth mixture, the combination of NWA and CS aggregates was considered at 50% substitution levels and in addition, the 25% of cement was replaced with bagasse ash. In conclusion, it was found that the combinations of CS and NWA increases the workability of the concrete mixes and showed 28-day compressive strength between 30 and 39 MPa with oven-dried density range of 1856 to 2103 kg/m3. Mix containing 50% CS and 25% bagasse ash showed significantly better performance in terms of drying shrinkage with the percentage reduction of about 18% compared to the coconut shell concrete (CSC), and this value was about 14% higher than the conventional normal weight concrete (NWC). In shear behavior, the contribution of CS and NWAs with 25% of cement replacement with bagasse ash showed higher shear performance compared to other beams containing 50% and 100% Coconut shell aggregates (CSA).

Market segmentation strategies can be used to overcome COVID‐19 vaccine hesitancy and other health crises

As the COVID‐19 pandemic continues to impact everyone to some degree, it has become clear that experts from many disparate fields must work together to overcome such public health crises. Even now, a significant portion of U.S. residents remain hesitant to receive a vaccine. In the quest to safely return to a fully open economy, time is of the essence, as many lives and livelihoods can be saved by even marginal improvements in vaccination rates. To reach widespread immunization sooner, science stands to benefit by using market segmentation strategies with vaccine holdouts, much like brands do with customers. As evidence, we present results from a national survey segmented into four groups of COVID‐19 vaccine holdouts. When viewed and considered as separate segments, important distinctions regarding the nature and strength of reasons behind COVID‐19 vaccine aversion, and the solutions to which people are most open, become clearer.

Formalizing Reasons, Oughts, and Requirements

Reasons-based accounts of our normative conclusions face difficulties in distinguishing between what ought to be done and what is required. This article addresses this problem from a formal perspective. I introduce a rudimentary formalization of a reasons-based account and demonstrate that that the model faces difficulties in accounting for the distinction between oughts and requirements. I briefly critique attempts to distinguish between oughts and requirements by appealing to a difference in strength or weight of reasons. I then present a formalized reasons-based account of permissions, oughts and requirements. The model exploits Joshua Gert (2004; 2007) and Patricia Greenspan’s (2005; 2007; 2010) suggestion that some reasons perform a purely justificatory function. I show that the model preserves the standard entailment relationships between requirements, oughts and permissions.

Alternative surface treatments for the repair of through-wall corrosion damage in metallic pipes with bonded plates

ABSTRACT Through-wall corrosion damage in pipelines can be repaired using a bonded metallic patch. Several parameters influence the repair performance, such as the surface preparation. Offshore oil platforms are restricted areas, and sparkling derived from surface preparation can have drastic consequences. Additionally, an industrial climber is required to access some areas that are difficult in the repairing process. In this work, the influence of alternative, easy to apply in the field, surface preparation methods on the burst pressure in pipes with defects repaired by a bonded metallic patch is investigated. Three different methods were considered: treatment with an abrasive-free rotating bristle machine and the application of a special primer directly on the oxidized surface without any additional mechanical treatment; and wet abrasive blasting. Initially, to verify the difference between these different systems, bonded single-lap joints are analyzed and then, hydrostatic tests in 6” diameter specimens with a circular hole of 1”. Although the use of a rotating bristle machine gives the best roughness and strength results, the other alternative methods are less time-consuming, assure reasonable strength, and are easier to be used in the field.

Mechanical properties of unidirectional bio-inspired composites with two non-self-similar hierarchical structures

There are many examples of hierarchical structures in nature such as teeth, antler, bone, and nacre which point to the possibility of creating new bio-inspired structures with superior mechanical properties. In this paper, the analysis of mechanical properties of uni-directional non-self-similar bio-inspired composites with two non-self-similar hierarchical structures is done using an existing popular model called Tension–Shear chain (TSC) model. We found that the so formed two hierarchical composites hold a good match with the Finite Element Analysis results in the case of Young’s modulus. These two hierarchical composites are seen to maintain a reasonable strength with very high toughness compared to that of the single hierarchical composites and may be used for applications where more toughness is required rather than strength. Moreover, the optimum aspect ratios at the first and second levels of hierarchies are evaluated in this study and a comparison of maximum toughness that can be achieved in a particular configuration is also made. These studies could be useful in the design and development of tough bio-inspired composites.

“Adding Up” Reasons: Lessons for Reductive and Nonreductive Approaches

How do multiple reasons combine to support a conclusion about what to do or believe? This question raises two challenges: (1) How can we represent the strength of a reason? (2) How do the strengths of multiple reasons combine? Analogous challenges about confirmation have been answered using probabilistic tools. Can reductive and nonreductive theories of reasons use these tools to answer their challenges? Yes, or more exactly: reductive theories can answer both challenges. Nonreductive theories, with the help of a (new?) result in confirmation theory, can answer one, and there are grounds for optimism that they can answer the other.

Upcycling of cementitious wastes in one-part alkaline cement binders

Cementitious wastes generate at an increasing rate and are generally disposed of in landfills, creating harmful environmental impacts. Therefore, enhancing potential pathways to recycle such wastes is critical. In this study, two ways of introducing cementitious wastes in one-part alkaline cement binders (ACBs) are presented: as solid precursors and as activators. A mixture of fly ash and blast furnace slag as the solid precursors and a blend of thermally treated sodium hydroxide and waste glass as the alkali activator were used to cast ACBs by just adding water similar to ordinary Portland cement. Glass powder-based activator showed 70% of efficiency in creating crystalline sodium silicate which dissolves in the binder phase to enhance the production of hydration products. Reasonable compressive strengths of the hardened paste were reported resulting in a dense microstructure with the curing age. Therefore, in this study, the increasing involvement of cementitious wastes in one-part ACBs is confirmed.

Solving the perpetual problem of imperative use heat curing for fly ash geopolymer cement by using sugar beet waste

This study aims to solve the perpetual problem of imperative use heat curing for fly ash (FA) geopolymer cement to obtain reasonable strength, especially at the early ages by using calcinated carbonation lime residue (CCR). The carbonation lime residue is a waste resulting from the sugar beet industry. For this purpose, FA was partially replaced with CCR at ratios fluctuated from 2.5% to 10%, by weight, with a step of 2.5%. FA geopolymer specimens with/without CCR were cured at room temperature. To investigate the effect of CCR on FA geopolymer cement, classical tests of flowability, setting time, compressive strength at various ages, water absorption and total porosity were explored. The results were analyzed by using advanced devices. The results showed that CCR is similar to CaO. The inclusion of CCR decreased setting time, flowability, water absorption and total porosity, whilst the compressive strength, especially at an early age, was enhanced. The optimum ratio of CCR was 7.5%, which provided the highest strength, lowest water absorption, lowest total porosity and acceptable setting time. Including a suitable ratio of CCR can accelerate the polymerization, form C-S-H gel, fill the pores and produce denser microstructure. The inclusion of 10% CCR showed too short setting time which did not provide enough time for handling, casting, compacting and finishing.

Fluidized bed processes and catalyst systems for Fischer-Tropsch conversion

Some binary and ternary combined manganese oxides of Mn with one or two additional metals or metalloids of Fe, Si, Ca and Mg were investigated as oxygen carriers for chemical-looping combustion (CLC) and chemical-looping with oxygen uncoupling (CLOU). More specifically the following systems were investigated: (1) MnyMgOx, (2) CaMnO3–(Fe0.25Mn0.75)2O3, (3) CaMnO3–(Fe0.67Mn0.33)2O3, (4) CaMnO3–MnMgOx, (5) MnMgOx–(Fe0.25Mn0.75)2O3 and (6) Mn2SiOx–Fe2SiOx. The general trend was that the binary systems, where two metals are used in the formulation showed the most promising results in terms of oxygen uncoupling and reactivity. However, there are several ternary combinations which show a combination of high oxygen uncoupling, reactivity with methane and reasonable strength. A pseudo first-order effective rate constant was evaluated for the investigated particles. The measured rates are lower than for benchmark nickel oxide and calcium manganites, but higher than for ilmenite. The ternary System 6, Mn2SiOx–Fe2SiOx was investigated in more depth, including solid fuel experiments to determine the rate of oxygen release. At 850 and 900 °C (Mn0.5Fe0.5)2SiOx had the highest average reactivity, with a maximum average yield of 91.5% at 850 °C. On the other hand, at higher temperatures, the particles with the highest Mn content showed best behavior, i.e. (Mn0.67Fe0.33)2SiOx. Reactivity experiments with char in the FB reactor with this OC showed that the oxygen capacity for CLOU was high, 3.5 wt% at 950 °C, with a maximum release rate of 0.2 g O2/kg OC,s. The low rate of uncoupling means that the experiments with gaseous fuel were likely dominated by the direct gas–solid reaction, and not CLOU. X-ray powder diffraction suggests that the main reaction path is via (MnxFe1−x)2O3 to (MnxFe1−x)3O4, although the reaction between Mn7SiO12 to MnSiO3 cannot be ruled out as a possible route of oxygen transfer. This was supported by thermodynamic calculations of this multi-component system.

A Public Health Reset Through Contractualism

A Public Health Reset Through Contractualism

High thermal durability of Ru-based synthetic antiferromagnet by interfacial engineering with Re insertion

Synthetic antiferromagnets (SAFs), composed of Ru spacer with a Re insertion layer, reveal superior thermal stability up to 450 °C annealing, making the back-end of line process a wider manufacturing window and tolerance to integrate the perpendicular magnetic tunneling junctions (P-MTJs) into CMOS process. The coupling strength decays significantly for SAFs with single Ru spacer after annealing above 400 °C. Due to the characteristics of refractory metals, Re can behave as a diffusion barrier during annealing. Furthermore, the Re spacer can still keep reasonable RKKY coupling strength. Therefore, the SAFs with Ru/Re composite spacers exhibit higher RKKY coupling strength than Ru spacers after 450 °C annealing. In addition, we discovered the different enhancements for the upper and lower interfacial Re insertion, which was attributed to the varied defect formation at interfaces. The stacking fault was formed at the upper Ru/Co interface in as-deposited state. When Re was inserted at the upper interface, the diffusion between Co and Ru was significantly suppressed and the stacking fault can be eliminated during annealing, leading to enhanced interlayer coupling. Through the interfacial engineering, we may have more degrees of freedom to tune the SAF performance and thus enhance process compatibility of P-MTJ to the CMOS process.