Behaviour of concrete columns with drilled holes

Holes drilled out to install additional services or equipment, such as for ducts through columns, beams or walls, can lead to loss of strength and possible structural failure. Until now little work has been done on holes in columns and, hence, the present study aims to examine the amount of strength lost owing to the presence of holes in columns. The reported experimental work deals with different parameters such as the number and dimensions of the holes and their relative position. It is shown that, for large diameter holes, a section capacity loss of up to 50% is possible. © 2006 Thomas Telford Ltd

Crustal interpretation of the MAGSAT data in the continental United States

The processing of MAGSAT scalar data to construct a crustal magnetic anomaly map over the continental U.S. involves removal of the reference field model, a path-by-path subtraction of a low order polynomial through a least-squares fit to reduce orbital offset errors, and a two dimensional spectral filtering to mitigate the spectral bias induced by the path-by-path orbital correction scheme. The resultant anomaly map shows reasonably good correlations with an aeromagnetic map derived from the project MAGNET. Prominent satellite magnetic anomalies are identified in terms of geological provinces and age boundaries. An inversion method was applied to MAGSAT data which produces both the Curie depth topography and laterally varying magnetic susceptibility of the crust. A contoured Curie depth map thus derived shows general agreements with a crustal thickness map based on seismic data

Drastic Reduction of Shot Noise in Semiconductor Superlattices

We have found experimentally that the shot noise of the tunneling current $I$ through an undoped semiconductor superlattice is reduced with respect to the Poissonian noise value $2eI$, and that the noise approaches 1/3 of that value in superlattices whose quantum wells are strongly coupled. On the other hand, when the coupling is weak or when a strong electric field is applied to the superlattice the noise becomes Poissonian. Although our results are qualitatively consistent with existing theories for one-dimensional mulitple barriers, the theories cannot account for the dependence of the noise on superlattice parameters that we have observed.Comment: 4 Pages, 3Figure

Transfer of Metacognitive Skills and Hint Seeking in Monkeys

Metacognition is knowledge that can be expressed as confidence judgments about what we know (monitoring) and by strategies for learning what we don’t know (control). Although a substantial literature exists on cognitive processes in animals, little is known about their metacognitive abilities. Here we show that rhesus macaques, trained previously to make retrospective confidence judgments about their performance on perceptual tasks, transferred that ability immediately to a new perceptual task and to a working memory task. In a second experiment we show that monkeys can also learn to request “hints” when they are given problems that they would otherwise have to solve by trial and error. This shows, for the first time, that non-human primates share with humans the ability to monitor and transfer their metacognitive ability both within and between different cognitive tasks, and to seek new knowledge on a need to know basis.

Microwave-driven ferromagnet--topological-insulator heterostructures: The prospect for giant spin battery effect and quantized charge pump devices

We study heterostructures where a two-dimensional topological insulator (TI) is attached to two normal metal (NM) electrodes while an island of a ferromagnetic insulator (FI) with precessing magnetization covers a portion of its lateral edges to induce time-dependent exchange field underneath via the magnetic proximity effect. When the FI island covers both lateral edges, such device pumps pure spin current in the absence of any bias voltage, thereby acting as an efficient spin battery with giant output current even at very small microwave power input driving the precession. When only one lateral edge is covered by the FI island, both charge and spin current are pumped into the NM electrodes. We delineate conditions for the corresponding conductances (current-to-microwave-frequency ratio) to be quantized in a wide interval of precession cone angles, which is robust with respect to weak disorder and can be further extended by changes in device geometry.Comment: 7 pages, 7 color figures, PDFLaTe

Magnetic permeability of near-critical 3d abelian Higgs model and duality

The three-dimensional abelian Higgs model has been argued to be dual to a scalar field theory with a global U(1) symmetry. We show that this duality, together with the scaling and universality hypotheses, implies a scaling law for the magnetic permeablity chi_m near the line of second order phase transition: chi_m ~ t^nu, where t is the deviation from the critical line and nu ~ 0.67 is a critical exponent of the O(2) universality class. We also show that exactly on the critical lines, the dependence of magnetic induction on external magnetic field is quadratic, with a proportionality coefficient depending only on the gauge coupling. These predictions provide a way for testing the duality conjecture on the lattice in the Coulomb phase and at the phase transion.Comment: 11 pages; updated references and small changes, published versio

Strategies for replacing saturated fat in meat products: A review

This paper aims to provide a better understanding of how to replace saturated fat in meat products due to concerns about its high amounts as health consciousness improves and consumers look for changes. In particular, we focused on various approaches and technologies to replace saturated fat in meat products. A systematic literature review was conducted using Web of Science, Google Scholar, and Scopus based on existing papers. The use of vegetable oils in meat products, oleogel and emulsion gel technologies, as well as application of protein substitutes were reviewed. The results show that the mentioned methods are potentially effective techniques for reducing the saturated fat content of meat products. As research on new approaches to fat substitutes continues to attract interest, we would like to highlight the research needs for the development of healthy meat products in the long term.This paper aims to provide a better understanding of how to replace saturated fat in meat products due to concerns about its high amounts as health consciousness improves and consumers look for changes. In particular, we focused on various approaches and technologies to replace saturated fat in meat products. A systematic literature review was conducted using Web of Science, Google Scholar, and Scopus based on existing papers. The use of vegetable oils in meat products, oleogel and emulsion gel technologies, as well as application of protein substitutes were reviewed. The results show that the mentioned methods are potentially effective techniques for reducing the saturated fat content of meat products. As research on new approaches to fat substitutes continues to attract interest, we would like to highlight the research needs for the development of healthy meat products in the long term

Electroweak phase transition in the MSSM with four generations

By assuming the existence of the sequential fourth generation to the minimal supersymmetric standard model (MSSM), we study the possibility of a strongly first-order electroweak phase transition. We find that there is a parameter region of the MSSM where the electroweak phase transition is strongly first order. In that parameter region, the mass of the lighter scalar Higgs boson is calculated to be above the experimental lower bound, and the scalar quarks of the third and the fourth generations are heavier than the corresponding quarks.Comment: 12 pages, 2 tables, 2 figure