Design and Development of an Adhesive Joint Testing Apparatus for Mixed-Mode Evaluation

The present work is dedicated to the development and design of a load jig inspired in theproposed solution by Fernlund and Spelt in order to characterize fracture of bonded joints undermixed-mode I+II loading. The jig allows for easy alteration of the mode-mixity and permits coveringthe full range of mixed-mode I+II combinations. A data reduction scheme based on specimencompliance, beam theory and crack equivalent concept is proposed to overcome several difficultiesinherent to the test analysis. The development was based in a design methodology using numericalvalidation based on experimental data obtained with a Dual Loading Frame from Virginia Tech. Thismethodology is presented and then validated with the experimental application of the jig

Determination of the envelopes for mode-mixity evaluation of adhesively bonded steel

This study is about the effect of the adhesive thickness and adhesive ductility on the mixed mode loading of DoubleCantilever Beam joints.The project is divided into three main tasks. The first task is about the development of a finite element model using acohesive zone model to design an experimental device based on the standard ASTM D6671D.The second task is concerned with the generation of experimental results in mixed mode varying the type of adhesiveand the adhesive thickness. In the third task, the experimental results will be used to develop an adhesive toughnessmodel as a function of the mode mixity.A dual actuator load frame from Virginia Techs Engineering Science & Mechanics Dept. was used to obtain theenvelopes for mode mixity for three different adhesives and thicknesses.A proposal for a data reduction scheme for the determination of the strain energy release rate is presented and validatedin this paper without the need of the experimental measure of the crack length

Mixed-Mode I + II fracture characterization of bonded joints using a novel Multi-Mode Apparatus

The present work presents the experimental test results to assess the toughness of an adhesive joint, using a previouslydefined crack equivalent data reduction scheme applied to a new multi-mode apparatus, inspired in a load jig previouslydeveloped by Fernlund and Spelt. The patented jig allows for easy alteration of the mode-mixity and permits coveringthe full range of mixed-mode I+II combinations. A data reduction scheme based on specimen compliance, beam theoryand crack equivalent concept is used to overcome several difficulties inherent to the test analysis. The method assumesthat the performed test can be viewed as a combination of the double cantilever beam and asymmetrically loaded endnotchedflexure tests, which provide modes I and II fracture characterization, respectively. A numerical analysisincluding a cohesive mixed-mode I+II damage model was performed considering different mixed-mode loadingconditions to validate the proposed data reduction scheme. Issues regarding self-similar crack growth and fractureprocess zone development are discussed. It was verified that the considered in-plane mix mode fracture criterion is wellcaptured using the proposed data reduction scheme

A live RSV vaccine with engineered thermostability is immunogenic in cotton rats despite high attenuation

Respiratory syncytial virus (RSV) is a leading cause of infant hospitalization and there remains no pediatric vaccine. RSV live-attenuated vaccines (LAVs) have a history of safe testing in infants; however, achieving an effective balance of attenuation and immunogenicity has proven challenging. Here we seek to engineer an RSV LAV with enhanced immunogenicity. Genetic mapping identifies strain line 19 fusion (F) protein residues that correlate with pre-fusion antigen maintenance by ELISA and thermal stability of infectivity in live RSV. We generate a LAV candidate named OE4 which expresses line 19F and is attenuated by codon-deoptimization of non-structural (NS1 and NS2) genes, deletion of the small hydrophobic (SH) gene, codon-deoptimization of the attachment (G) gene and ablation of the secreted form of G. OE4 (RSV-A2-dNS1-dNS2-ΔSH-dGm-Gsnull-line19F) exhibits elevated pre-fusion antigen levels, thermal stability, immunogenicity, and efficacy despite heavy attenuation in the upper and lower airways of cotton rats

What Happened to the Bondholding Class? Public Debt, Power and the Top One Per Cent

In 1887 Henry Carter Adams produced a study demonstrating that the ownership of government bonds was heavily concentrated in the hands of a ‘bondholding class’ that lent to and, in Adams's view, controlled the government like dominant shareholders control a corporation. The interests of this bondholding class clashed with the interests of the masses, whose burdensome taxes financed the interest payments on government bonds. Since the late nineteenth century there has been plenty of debate about the ownership of the public debt. But the empirical evidence offered to support the various arguments has been scant. As a result, political economists have few answers to questions first raised by Adams over century ago: how has the pattern of public debt ownership changed? Can we still speak of a powerful ‘bondholding class’? Does public debt redistribute income from taxpayers to public creditors? This article develops a new framework to address these questions. Anchored within a ‘capital as power’ approach, the research indicates a staggering pattern of concentration in the ownership of US public debt in the hands of the top one per cent of US households over the past three decades. Accordingly, the bondholding class is still alive and well in contemporary US capitalism

The routinisation of management controls in software.

Author's post-print version. Final version published by Springer; available online at http://link.springer.com/Our paper aims to explore management control as complex and intertwining process over time, rather than the (mainstream) fixation on rational, optimising tools for ensuring business success. We set out to contribute towards our understanding of why and how particular management controls evolve over time as they do. We discuss how the management control routines of one organisation emerged and reproduced (through software), and moved towards a situation of becoming accepted and generally unquestioned across much of the industry. The creativity and championing of one particular person was found to be especially important in this unfolding change process. Our case study illuminates how management control (software) routines can be an important carrier of organisational knowledge, both as an engine for continuity but also potentially as a catalyst for change. We capture this process by means of exploring the ‘life-story’ of a piece of software that is adopted in the corrugated container industry

Has Behavioral Science Tumbled Through the Biological Looking Glass? Will Brief, Evidence-Based Training Return It From the Rabbit Hole?

Time constraints and professional demands leave practicing professionals unlikely to enroll in extended training such as a semester-long graduate course. Thus, the three-hour continuing education format has become a standard for those in practice. One may ask what sorts of training strategies optimize that format. To explore that, a three hour training program for seventy-six practicing mental health professionals, most of whom self-identified as psychologists, was devised. It made use of primarily antecedent techniques that have been shown to bring about changed perceptions on a number of topics. Content focused on two areas of importance to behavior analysts, the culture’s increasing acceptance of the biological causation model of disorders such as attentiondeficit hyperactivity disorder (ADHD), unipolar depression, anxiety disorders, and schizophrenia, and the field’s increasing reliance on medications, often to the exclusion of behavioral methods. Pre-post assessment showed that participants had changed their thinking regarding the two content areas. The authors caution that participants’ changed opinions may serve as setting events to changes in practice, but those changes are verbal. One must not assume changes in practice techniques will automatically occur

Skunk River Review September 1990, vol 2

https://openspace.dmacc.edu/skunkriver/1005/thumbnail.jp

Characterization of the Single Stranded DNA Binding Protein SsbB Encoded in the Gonoccocal Genetic Island

Background: Most strains of Neisseria gonorrhoeae carry a Gonococcal Genetic Island which encodes a type IV secretion system involved in the secretion of ssDNA. We characterize the GGI-encoded ssDNA binding protein, SsbB. Close homologs of SsbB are located within a conserved genetic cluster found in genetic islands of different proteobacteria. This cluster encodes DNA-processing enzymes such as the ParA and ParB partitioning proteins, the TopB topoisomerase, and four conserved hypothetical proteins. The SsbB homologs found in these clusters form a family separated from other ssDNA binding proteins. Methodology/Principal Findings: In contrast to most other SSBs, SsbB did not complement the Escherichia coli ssb deletion mutant. Purified SsbB forms a stable tetramer. Electrophoretic mobility shift assays and fluorescence titration assays, as well as atomic force microscopy demonstrate that SsbB binds ssDNA specifically with high affinity. SsbB binds single-stranded DNA with minimal binding frames for one or two SsbB tetramers of 15 and 70 nucleotides. The binding mode was independent of increasing Mg 2+ or NaCl concentrations. No role of SsbB in ssDNA secretion or DNA uptake could be identified, but SsbB strongly stimulated Topoisomerase I activity