Centrifugal stresses in arbitrarily laminated, rectangular—anistropic circular discs

The problem is formulated as one in the linear theory of thin, laminated, anisotropic elastic plates. A direct force-and-moment formulation is used, simplifying approximation is introduced and a closed-form solution is obtained. This solution exhibits bending-stretching coupling if the plate is asymmetrically laminated with respect to mass or stiffness or both. Numerical results typical of certain composite materials of current interest are presented. Specific laminates considered as examples include (1) glass—epoxy/steel, (2) cross-ply graphite—epoxy, and (3) various quasi-isotropic layups of organic fibre—epoxy.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Issues in providing a reliable multicast facility

Issues involved in point-to-multipoint communication are presented and the literature for proposed solutions and approaches surveyed. Particular attention is focused on the ideas and implementations that align with the requirements of the environment of interest. The attributes of multicast receiver groups that might lead to useful classifications, what the functionality of a management scheme should be, and how the group management module can be implemented are examined. The services that multicasting facilities can offer are presented, followed by mechanisms within the communications protocol that implements these services. The metrics of interest when evaluating a reliable multicast facility are identified and applied to four transport layer protocols that incorporate reliable multicast

A Terraced Scanning Superconducting Quantum Interference Device Susceptometer with Sub-Micron Pickup Loops

Superconducting Quantum Interference Devices (SQUIDs) can have excellent spin sensitivity depending on their magnetic flux noise, pick-up loop diameter, and distance from the sample. We report a family of scanning SQUID susceptometers with terraced tips that position the pick-up loops 300 nm from the sample. The 600 nm - 2 um pickup loops, defined by focused ion beam, are integrated into a 12-layer optical lithography process allowing flux-locked feedback, in situ background subtraction and optimized flux noise. These features enable a sensitivity of ~70 electron spins per root Hertz at 4K.Comment: See http://stanford.edu/group/moler/publications.html for an auxiliary document containing additional fabrication details and discussio

Generalized bending of a plate with a circular inclusion of arbitrary rigidity

The paper presents an exact closed-form solution for a thin isotropic plate containing a circular elastic inclusion and subjected to arbitrary bending moments at large distances from the hole. Quantitative results are presented for the bending stress concentration factors for the plate and for the inclusion.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

Nematode assemblages in a nature reserve with historical pollution

Nematodes, and especially nematode communities, have significant potential as bio-indicators. The present studyaimed to assess the nematode community structure of several sites with different historical pollution. Long-term polluted municipal waste-, tar- and sludge- sites were compared with less disturbed annex sites. At each site heavy metal and PAHs concentrations were measured together with soil texture classes, pH and total organic matter. Identification of three hundred nematodes at each location resulted in the discrimination of 63 genera from 32 different families of which the Cephalobidae, Belonolaimidae, Tylenchidae, Hoplolaimidae, Belonolaimidae and Plectidae were the most abundant families. The sampling sites harbour significantly different nematode communities and significant differences of life-strategy-related parameters (cp-groups, MI indexes) wereobserved. The significant augmentation of the proportion of the cp 2 nematodes in historically-polluted sites was especially informative. Omitting the cp 1 group from the MI (=MI2-5) better reflects putative historical pollution-induced community changes. However, the current study did not reveal significant relationships between historical pollution and the feeding type composition, or the Shannon-Wiener diversity. The observed results are critically assessed in the light of possible flaws such as sampling and analyzing limitations

Improved Equation for Shear Modulus Using Four-Point Ring-Twist Test Data

There are numerous test-specimen configurations for determining the static shear modulus of composites. Selection of specimen configuration depends primarily on product component configuration. Two-ring specimens in use are the split-ring twist specimen and the four-point-loading ring-twist specimen. The latter is more advantageous, since it uses an intact ring. However, reported validation tests on aluminum rings showed a large error in predicted shear modulus. The present paper provides an improved analysis that takes into account the tilting of the cross section on the loading bar.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

A Self-Calibrating Eddy-Current Instrument

The calibration of eddy-current measurement systems is a long-standing problem in nondestructive evaluation. Calibration serves a number of purposes: for equipment setup and validation, for equalizing responses from different probes and instruments, for setting detection thresholds, and for quantitative flaw sizing. The most commonly used calibration method is to scan the probe to be calibrated over simulated defects such as electrical-discharge machined (EDM) slots, saw cuts, or laboratory-produced fatigue cracks. This method has the virtue of calibrating probe and instrument at the same time on the same material as that to be inspected. But it has a number of disadvantages as well. First, a large number of artifact standards must be generated, certified, and maintained in the typical inspection organization; this can result in considerable expense. Second, the signals from EDM slots and saw cuts are not equivalent to the signals from actual defects, as discussed in another paper in these proceedings [1]. Third, quantitative flaw sizing can only be accomplished over a limited range with such calibration methodology, and the accuracy of sizing flaws with this method is brought into question by the aforementioned inequality of slots and cracks. Even if laboratory-produced cracks were to be used routinely for calibration (a prohibitively expensive option), quantitative sizing could be compromised by the occurrence of crack closure effects [2]

Effects of TDP2/VPg Unlinkase Activity on Picornavirus Infections Downstream of Virus Translation.

In this study, we characterized the role of host cell protein tyrosyl-DNA phosphodiesterase 2 (TDP2) activity, also known as VPg unlinkase, in picornavirus infections in a human cell model of infection. TDP2/VPg unlinkase is used by picornaviruses to remove the small polypeptide, VPg (Virus Protein genome-linked, the primer for viral RNA synthesis), from virus genomic RNA. We utilized a CRISPR/Cas-9-generated TDP2 knock out (KO) human retinal pigment epithelial-1 (hRPE-1) cell line, in addition to the wild type (WT) counterpart for our studies. We determined that in the absence of TDP2, virus growth kinetics for two enteroviruses (poliovirus and coxsackievirus B3) were delayed by about 2 h. Virus titers were reduced by ~2 log10 units for poliovirus and 0.5 log10 units for coxsackievirus at 4 hours post-infection (hpi), and by ~1 log10 unit at 6 hpi for poliovirus. However, virus titers were nearly indistinguishable from those of control cells by the end of the infectious cycle. We determined that this was not the result of an alternative source of VPg unlinkase activity being activated in the absence of TPD2 at late times of infection. Viral protein production in TDP2 KO cells was also substantially reduced at 4 hpi for poliovirus infection, consistent with the observed growth kinetics delay, but reached normal levels by 6 hpi. Interestingly, this result differs somewhat from what has been reported previously for the TDP2 KO mouse cell model, suggesting that either cell type or species-specific differences might be playing a role in the observed phenotype. We also determined that catalytically inactive TDP2 does not rescue the growth defect, confirming that TDP2 5' phosphodiesterase activity is required for efficient virus replication. Importantly, we show for the first time that polysomes can assemble efficiently on VPg-linked RNA after the initial round of translation in a cell culture model, but both positive and negative strand RNA production is impaired in the absence of TDP2 at mid-times of infection, indicating that the presence of VPg on the viral RNA affects a step in the replication cycle downstream of translation (e.g., RNA synthesis). In agreement with this conclusion, we found that double-stranded RNA production (a marker of viral RNA synthesis) is delayed in TDP2 KO RPE-1 cells. Moreover, we show that premature encapsidation of nascent, VPg-linked RNA is not responsible for the observed virus growth defect. Our studies provide the first lines of evidence to suggest that either negative- or positive-strand RNA synthesis (or both) is a likely candidate for the step that requires the removal of VPg from the RNA for an enterovirus infection to proceed efficiently

Manipulation of charge carrier injection into organic field-effect transistors by self-assembled monolayers of alkanethiols

Charge carrier injection into two semiconducting polymers is investigated in field-effect transistors using gold source and drain electrodes that are modified by self-assembled monolayers of alkanethiols and perfluorinated alkanethiols. The presence of an interfacial dipole associated with the molecular monolayer at the metal/semiconductor interface changes the work function of the electrodes, and, hence, the injection of the charge carriers. The FET characteristics are analysed with the transfer line method and the hole injection into poly(2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylene vinylene) (MEH-PPV) and regio-regular poly(3-hexyl)thiophene (rr-P3HT) is investigated. The device parameters are corrected for the contact resistances of the electrodes and the mobilities of the polymers (MEH-PPV, µFET = 4 × 10-4 cm2 V-1 s-1 and rr-P3HT, µFET = (1–2) × 10-2 cm2 V-1 s-1) are determined. The contact resistance obtained for the SAM-modified electrodes is at least one order of magnitude larger than for untreated contacts.