Fatigue limit under multiaxial loadings: on the definition of the equivalent shear stress

The goal of the present paper is to propose a criterion to predict the fatigue strength of hard metals under conditions of multiaxial, non-proportional loadings. It is very simple to compute, but still provides very good results for a wide range of in-phase and out-of-phase cycling loads.     

The National Soil Information System (NASIS): Designing soil interpretation classes for military land-use predictions

The focus of the National Cooperative Soil Survey is shifting from producing static, printed soil survey reports to providing a dynamic resource of soils information for a wide range of needs. The National Soil Information System (NASIS) is the core component of this vision and is designed to manage and maintain soil data from collection to dissemination. NASIS supports this conceptual shift in three important areas: (1) collection of new information in compliance with standards, (2) application of expert knowledge to make information usable for a variety of purposes, and (3) dissemination of information to a wide variety of users. This paper demonstrates the use of NASIS for evaluating the suitability of military lands for vehicle related land-use activities.     

A mathematical assessment of the isolation random forest method for anomaly detection in big data

We present the mathematical analysis of the Isolation Random Forest Method (IRF Method) for anomaly detection, proposed by Liu F.T., Ting K.M. and Zhou Z. H. in their seminal work as a heuristic method for anomaly detection in Big Data. We prove that the IRF space can be endowed with a probability induced by the Isolation Tree algorithm (iTree). In this setting, the convergence of the IRF method is proved, using the Law of Large Numbers. A couple of counterexamples are presented to show that the method is inconclusive and no certificate of quality can be given, when using it as a means to detect anomalies. Hence, an alternative version of the method is proposed whose mathematical foundation is fully justified. Furthermore, a criterion for choosing the number of sampled trees needed to guarantee confidence intervals of the numerical results is presented. Finally, numerical experiments are presented to compare the performance of the classic method with the proposed one.     

One‐Pot Synthesis of Carbon‐Coated Nanostructured Iron Oxide on Few‐Layer Graphene for Lithium‐Ion Batteries

Nanostructure engineering has been demonstrated to improve the electrochemical performance of iron oxide based electrodes in Li‐ion batteries (LIBs). However, the synthesis of advanced functional materials often requires multiple steps. Herein, we present a facile one‐pot synthesis of carbon‐coated nanostructured iron oxide on few‐layer graphene through high‐pressure pyrolysis of ferrocene in the presence of pristine graphene. The ferrocene precursor supplies both iron and carbon to form the carbon‐coated iron oxide, while the graphene acts as a high‐surface‐area anchor to achieve small metal oxide nanoparticles. When evaluated as a negative‐electrode material for LIBs, our composite showed improved electrochemical performance compared to commercial iron oxide nanopowders, especially at fast charge/discharge rates.     

Bioanalysis by Immobilization of Antibodies on Hafnium(IV) Oxide with 3-Aminopropyltriethoxysilane

Self-assembled monolayers of 3-aminopropyltriethoxysilane (APTES) are commonly used to promote adhesion between substrates and organic or metallic materials with applications ranging from advanced composites to biomolecular lab-on-a-chip devices. In this work, the silanization on hafnium oxide (HfO₂) films is reported. The layers of HfO₂ were deposited on Si (001) substrates by atomic layer deposition. The grown HfO₂ films were modified in accordance with three main steps: oxidation, silanization, and cross-linking of the APTES monolayer using glutaraldehyde as cross-linking agent. Microscopic features were characterized by atomic force microscopy. Further, both bovine serum albumin and antibovine serum albumin agents were deposited on the samples to test their potential use as the immunosensor.     

Type O pure radiation metrics with a cosmological constant

In this paper we complete the integration of the conformally flat pure radiation spacetimes with a non-zero cosmological constant Λ, and , by considering the case . This is a further demonstration of the power and suitability of the generalised invariant formalism (GIF) for spacetimes where only one null direction is picked out by the Riemann tensor. For these spacetimes, the GIF picks out a second null direction (from the second derivative of the Riemann tensor) and once this spinor has been identified the calculations are transferred to the simpler GHP formalism, where the tetrad and metric are determined. The whole class of conformally flat pure radiation spacetimes with a non-zero cosmological constant (those found in this paper, together with those found earlier for the case ) have a rich variety of subclasses with zero, one, two, three, four or five Killing vectors.     

Self-assembly of semifluorinated n-alkanethiols on {111}-oriented Au investigated with scanning tunneling microscopy experiment and theory

The adsorption of semifluorinated alkanethiols on Au/mica was studied by scanning tunneling microscopy (STM). The adlayer structure produced is based on a p(2 x 2) structure though lines of molecules displayed extensive kinks and bends. In addition, a considerable variation in the contrast of molecular features is found. Molecular modeling calculations confirm that, for the fluorinated thiols, inequivalently adsorbed molecules within a p(2 x 2) registry are present, an aspect that endows the local structure of the adlayer with a higher flexibility in comparison to nonfluorinated thiols, where one adsorption site is strongly favored in a (radical 3 x radical 3) R30 degrees structure. Simulated STM imaging on the optimized systems successfully recovered the effects on the molecular feature contrast induced by the flexibility of the fluorinated thiol adlayer.