Nondestructive Evaluation of Wood using Ultrasonic Frequency Domain Analysis

In-situ performance assessment of wooden structural components are very important for maintenance and rehabilitation of timber structures. Nondestructive evaluation (NDE) methods can play an important role in the in-situ assessment of structural performance. The ultrasonic technique has been found to be more accurate than the conventional practice of visual inspection in assessing the defects such as decays, knots, and splits in wood [1]

Constraining nuclear physics parameters with current and future COHERENT data

Motivated by the recent observation of coherent elastic neutrino-nucleus scattering (CE$\nu$NS) at the COHERENT experiment, our goal is to explore its potential in probing important nuclear structure parameters. We show that the recent COHERENT data offers unique opportunities to investigate the neutron nuclear form factor. Our present calculations are based on the deformed Shell Model (DSM) method which leads to a better fit of the recent CE$\nu$NS data, as compared to known phenomenological form factors such as the Helm-type, symmetrized Fermi and Klein-Nystrand. The attainable sensitivities and the prospects of improvement during the next phase of the COHERENT experiment are also considered and analyzed in the framework of two upgrade scenarios.Comment: 13 pages, 5 figures, 2 tables; v2: minor corrections, version to appear in PL

Nondestructive Evaluation of Wood Using Ultrasonic Dry-Coupled Transducers

The nondestructive evaluation of wood is of considerable importance in several structural applications such as wooden bridge decks, wooden structural components, and wooden railway ties. This problem has attracted the attention of several researchers [1–19]. The specific topics that are being considered include: detection of natural defects like bacterial growth, knots, and splits; grading of wood; estimation of strength and stiffness characteristics; assessment of the effect of chemical treatment on strength; and, in-situ evaluation of degradation in wooden structural components and railway ties. Ultrasonic techniques have achieved a reasonable amount of success in the estimation of structural properties and defects [11, 16, 18]. Detection of natural defects such as knots, splits and decays provides valuable information which can be used for the grading of wood. The wave velocity measurements can also be used for the determination of structural properties (e.g., modulus of elasticity) of wood leading to grading, and to monitor the in-situ degradation of wooden structural members exposed to loads and environmental conditions

Probing the N=14N = 14 subshell closure: gg factor of the 26^{26}Mg(21+^+_1) state

The first-excited state $g$~factor of $^{26}$Mg has been measured relative to the $g$ factor of the $^{24}$Mg($2^+_1$) state using the high-velocity transient-field technique, giving $g=+0.86\pm0.10$. This new measurement is in strong disagreement with the currently adopted value, but in agreement with the $sd$-shell model using the USDB interaction. The newly measured $g$ factor, along with $E(2^+_1)$ and $B(E2)$ systematics, signal the closure of the $\nu d_{5/2}$ subshell at $N=14$. The possibility that precise $g$-factor measurements may indicate the onset of neutron $pf$ admixtures in first-excited state even-even magnesium isotopes below $^{32}$Mg is discussed and the importance of precise excited-state $g$-factor measurements on $sd$~shell nuclei with $N\neq Z$ to test shell-model wavefunctions is noted.Comment: 8 pages, 5 figure

Optimal Control of An Sir Model With Changing Behavior Through An Education Campaign

An SIR type model is expanded to include the use of education or information given to the public as a control to manage a disease outbreak when effective treatments or vaccines are not readily available or too costly to be widely used. The information causes a change in behavior resulting in three susceptible classes. We study stability analysis and use optimal control theory on the system of differential equations to achieve the goal of minimizing the infected population (while minimizing the cost). We illustrate our results with some numerical simulations

Biochemical Effects of Exercise on a Fasciocutaneous Flap in a Rat Model.

Importance: An overwhelming amount of data suggest that cardiovascular exercise has a positive effect on the mind and body, although the precise mechanism is not always clear. Objective: To assess the clinical and biochemical effects of voluntary cardiovascular exercise on pedicled flaps in a rodent model. Design, Setting, and Participants: Eighteen adult Sprague-Dawley male rats were randomized into a resting animal group (RAG) (n=9) and an exercise animal group (EAG) (n=9) for 14 days (July 23, 2013, through July 30, 2013). A pedicled transposition flap was performed on the ventral surface of the rat, and biopsy specimens were taken from the proximal, middle, and distal portions on postoperative days 0, 2, 5, and 9. Flap survival was analyzed planimetrically, and biopsy specimens were analyzed by hematoxylin-eosin-stained microscopy and immunoblotting. The housing, exercise, surgery, and analysis of the rats were conducted at a single basic science research laboratory at the tertiary care center campus of Thomas Jefferson University in Philadelphia, Pennsylvania. Exposures: The rats were caged for 14 days or housed in a cage connected to an exercise wheel and pedometer. Main Outcomes and Measures: Study measures were gross and micrographic necrosis and expression of proteins within cell survival and apoptosis pathways. Results: A total of 18 rats were studied, 9 in the RAG and 9 in the EAG. the mean (SEM) amount of necrosis in flaps was 41.3% (3%) in the RAG rats and 10.5% (3.5%) in the EAG rats (P \u3c .001). Immunoblotting revealed increased Caspase-9 activity resulting in poly-(adenosine diphosphate-ribose) polymerase 1 cleavage in the RAG vs the EAG, as well as lower phosphorylated protein kinase B (also known as Akt), signal transducer and activator of transcription 3, and total B-cell leukemia/lymphoma 2 protein levels. Throughout the postoperative period, the cumulative vascular endothelial growth factor A levels of the EAG flaps were significantly higher than those of the RAG flaps (2.30 vs 1.25 fold induction [FI], P = .002), with differences of 2.76 vs 1.54 FI in the proximal segment, 2.40 vs 1.20 FI in the middle segment, and 1.90 vs 0.79 FI in the distal segment. A similar response was noted when comparing phosphorylated Akt, with cumulative mean (SEM) p-Akt expression levels of 0.62 (0.04) for RAG and 1.98 (0.09) for EAG (P = .002 between the 2 groups). Conclusions and Relevance: Voluntary preoperative exercise improves survival in pedicled fasciocutaneous flaps; the EAG rats had less necrosis, decreased apoptotic markers, and increased amounts of vascular endothelial growth factor A and prosurvival proteins. These results have implications to increase flap survival in other mammal populations, such as humans. Level of Evidence: 3

Analytical Investigation of Sound Radiation from Functionally Graded Thin Plates Based on Elemental Radiator Approach and Physical Neutral Surface

This paper analyzes the sound radiation behavior of a clamped thin, functionally graded material plate using the classical plate theory and Rayleigh Integral with the elemental radiator approach. The material properties of the plate are assumed to vary according to the power-law distribution of the constituent materials in the transverse direction. The functionally graded material is modeled using a physical neutral surface instead of a geometric middle surface. The effects of the power-law index, elastic modulus ratio, different constituent materials, and damping loss factor on the sound radiation of functionally graded plate are analyzed. It was found that, for the considered plate, the power-law index significantly influences sound power level and radiation efficiency. There exists a critical value of the power-law index for which the corresponding peak of sound power level is minimum. In a wide operating frequency range, approximately 500–1500 Hz, this research suggests that the radiation efficiency is lower for the power-law index equal to 0 and 1. However, for very low frequencies (less than 250 Hz), the power-law index does not affect radiation efficiency significantly. Further, as the modulus ratio increases, the sound power peak decreases for a given power-law index. For the given material constituents of the functionally graded plate, the different values of damping loss factors do not significantly influence radiation efficiency. However, the selection of material constituents affects the radiation efficiency peak

Ram pressure stripping of the multiphase ISM in the Virgo cluster spiral galaxy NGC 4438

Ram pressure stripping of the multiphase ISM is studied in the perturbed Virgo cluster spiral galaxy NGC 4438. This galaxy underwent a tidal interaction ~100 Myr ago and is now strongly affected by ram pressure stripping. Deep VLA radio continuum observations at 6 and 20 cm are presented. We detect prominent extraplanar emission to the west of the galactic center, which extends twice as far as the other tracers of extraplanar material. The spectral index of the extraplanar emission does not steepen with increasing distance from the galaxy. This implies in situ re-acceleration of relativistic electrons. The comparison with multiwavelength observations shows that the magnetic field and the warm ionized interstellar medium traced by Halpha emission are closely linked. The kinematics of the northern extraplanar Halpha emission, which is ascribed to star formation, follow those of the extraplanar CO emission. In the western and southern extraplanar regions, the Halpha measured velocities are greater than those of the CO lines. We suggest that the ionized gas of this region is excited by ram pressure. The spatial and velocity offsets are consistent with a scenario where the diffuse ionized gas is more efficiently pushed by ram pressure stripping than the neutral gas. We suggest that the recently found radio-deficient regions compared to 24 mum emission are due to this difference in stripping efficiency.Comment: 8 pages, 6 figures, A&A, accepted for publicatio