Cohesive Strength Prediction of Adhesive Joints

My part of this program was to investigate a nondestructive method for measuring the cohesive strength properties of adhesively bonded joints. I started this problem by viewing a reasonably fundamental study in modeling the adhesive as a layer between two infinite aluminum adherends. You can set up wave potentials in these different regions in terms of reflected and transmitted waves, as is seen in Fig. 1. If you set up your wave number in a very classical manner, where everything is elastic and there is no damping, you just get a regular Rayleigh-type solution. If you desire to include the damping of the adhesive layer, then you must have a complex wave number. The appropriate relationship was derived by Brekhovshikh. We took his relationships and did parametric studies on the bond line in terms of the acoustic properties of the adhesive

From cartonera publishing practices to trans-formal methods for qualitative research

Interdisciplinarity, multidisciplinarity and counter-disciplinarity are the hallmark of cultural studies and qualitative research, as scholars over the past three decades have discussed through extensive self-reflexive inquiry into their own unstable and ever-shifting methods (Denzin and Lincoln, 2018; Dicks et al., 2006: 78; Grossberg, 2010). Building on the interdisciplinary thought of Jacques Rancière and Caroline Levine on the one hand and traditions of participatory action research and activist anthropology on the other, we bring the methods conversation forward by shifting the focus from disciplines to forms and by making a case for aesthetic practice as qualitative research process. In this paper, the question of methods is approached through the action-based Cartonera Publishing Project with editoriales cartoneras in Latin America – community publishers who make low-cost books out of materials recovered from the street in the attempt to democratise and decolonise literary/artistic production – and specifically through our process-oriented, collaborative work with four cartonera publishers in Brazil and Mexico. Guided by the multiple forms of cartonera knowledge production, which are rooted not in academic research but rather in aesthetic practice and community relations, we offer an innovative ‘trans-formal’ methodological framework, which opens up new pathways for practitioners and researchers to work, think and act across social, cultural and aesthetic forms

From cartonera publishing practices to trans-formal methods for qualitative research

Interdisciplinarity, multidisciplinarity and counter-disciplinarity are the hallmark of cultural studies and qualitative research, as scholars over the past three decades have discussed through extensive self-reflexive inquiry into their own unstable and ever-shifting methods (Denzin and Lincoln, 2018; Dicks et al., 2006: 78; Grossberg, 2010). Building on the interdisciplinary thought of Jacques Rancière and Caroline Levine on the one hand and traditions of participatory action research and activist anthropology on the other, we bring the methods conversation forward by shifting the focus from disciplines to forms and by making a case for aesthetic practice as qualitative research process. In this paper, the question of methods is approached through the action-based Cartonera Publishing Project with editoriales cartoneras in Latin America – community publishers who make low-cost books out of materials recovered from the street in the attempt to democratise and decolonise literary/artistic production – and specifically through our process-oriented, collaborative work with four cartonera publishers in Brazil and Mexico. Guided by the multiple forms of cartonera knowledge production, which are rooted not in academic research but rather in aesthetic practice and community relations, we offer an innovative ‘trans-formal’ methodological framework, which opens up new pathways for practitioners and researchers to work, think and act across social, cultural and aesthetic forms

A 40 Year Time Series of SBUV Observations: the Version 8.6 Processing

Under a NASA program to produce long term data records from instruments on multiple satellites (MEaSUREs), data from a series of eight SBUV and SBUV 12 instruments have been reprocessed to create a 40 year long ozone time series. Data from the Nimbus 4 BUV, Nimbus 7 SBUV, and SBUV/2 instruments on NOAA 9, 11, 14, 16, 17, and 18 were used covering the period 1970 to 1972 and 1979 to the present. In past analyses an ozone time series was created from these instruments by adjusting ozone itself, instrument by instrument, for consistency during overlap periods. In the version 8.6 processing adjustments were made to the radiance calibration of each instrument to maintain a consistent calibration over the entire time series. Data for all eight instruments were then reprocessed using the adjusted radiances. Reprocessing is necessary to produce an accurate latitude dependence. Other improvements incorporated in version 8.6 included the use of the ozone cross sections of Brion, Daumont, and Malicet, and the use of a cloud height climatology derived from Aura OMI measurements. The new cross sections have a more accurate temperature dependence than the cross sections previously used. The OMI-based cloud heights account for the penetration of UV into the upper layers of clouds. The consistency of the version 8.6 time series was evaluated by intra-instrument comparisons during overlap periods, comparisons with ground-based instruments, and comparisons with measurements made by instruments on other satellites such as SAGE II and UARS MLS. These comparisons show that for the instruments on NOAA 16, 17 and 18, the instrument calibrations were remarkably stable and consistent from instrument to instrument. The data record from the Nimbus 7 SBUV was also very stable, and SAGE and ground-based comparisons show that the' calibration was consistent with measurements made years laterby the NOAA 16 instrument. The calibrations of the SBUV/2 instruments on NOAA 9, 11, and 14 were more of a problem. The rapidly drifting orbits of these satellites resulted in relative time and altitude dependent differences that are significant. Despite these problems, total column ozone appears to be consistent to better than 1% over the entire time series, while the ozone vertical distribution is consistent to approximately 5%

Water Quality, nutrients and the European Union’s Water Framework Directive in a lowland agricultural region: Suffolk, south-east England.

The water quality of 13 rivers in the lowland, agricultural county of Suffolk is investigated using routine monitoring data for the period 1981 to 2006 collected by the Environment Agency of England and Wales (EA), and its predecessors, with particular emphasis on phosphorus (as total reactive phosphorus, TRP) and total (dissolved and particulate) oxidised nitrogen (TOxN – predominantly nitrate NO3). Major ion and flow data are used to outline fundamental hydrochemical characteristics related to the groundwater provenance of base-flow waters. Relative load contributions from point and diffuse sources are approximated using Load Apportionment Modelling for both TRP and TOxN where concurrent flow and concentration data are available. Analyses indicate a mixture of point and diffuse sources of TRP, with the former being dominant during low flow periods, while for TOxN diffuse sources dominate. Out of 59 sites considered, 53 (90%) were found to have annual average TRP concentrations greater than 0.05 mg P l-1, and 36 (61%) had average concentrations over 0.120 mg P l-1, the upper thresholds for ‘High’ and ‘Good’ ecological status, respectively. Correspondingly, for TOxN, most of the rivers are already within 70% of the 11.3 mg N l-1 threshold, with two rivers (Wang and Ore) being consistently greater than this. It is suggested that the major challenge is to characterise and control point-source TRP inputs which, being predominant during the late spring and summer low-flow period, coincide with the peak of primary biological production, thus presenting the major challenge to achieving ‘good’ ecological status under the Water Framework Directive. Results show that considerable effort is still required to ensure appropriate management and develop tools for decision-support

A Kuiper Belt Source for Solar Flare Track-Rich Interplanetary Dust Particles

The presence of solar flare particle tracks in mineral grains within interplanetary dust particles (IDPs) has long been accepted as proof of their extraterrestrial origin [e.g. 1]. The 10-20 micrometers diameter IDPs released by dust producing objects in the solar system (mainly comets and asteroids) spiral in towards the Sun under the influence of Poynting-Robertson (PR) drag forces [2] and accumulate solar flare energetic particle tracks during their journey. The number of IDPs with well-constrained track density measurements is small, owing to the difficulty in the measurements and the lack of appropriatelysized crystals in which to image them. In order to use track densities as a chronometer of space exposure, the track production rate must be known. All previous work relied on track production rates determined by chemical etching techniques [e.g. 3], but tracks in IDPs are measured using TEM imaging. Here we report measurements of track densities in IDPs from both the anhydrous and hydrated IDP groups. Using the track production calibration determined from TEM observations of anorthite and olivine in lunar rock 64455 [4] we estimate space exposure times for these IDPs to constrain their parent body sources

STARDUST and Interplanetary Dust Particles - Big Science from Small Samples

Comets are primitive bodies that are widely believed to be a reservoir of preserved interstellar and circumstellar grains, and molecular cloud materials (organics). Direct samples of cometary dust along with interstellar grains will be returned by the STARDUST Mission in 2006. Analyses of interplanetary dust particles (IDPs) and analogue materials in the laboratory provide constraints and serve as "ground truth" for evaluating various hypotheses on the nature of comets and interstellar grains. Anhydrous IDPs are the most primitive remnants of the primordial Solar System, and are our only known samples of comets. These cometary lDPs are rich in preserved interstellar organic compounds II]. In addition, abundant interstellar silicates have recently been discovered in cluster lDPs [2]. In some of these IDPs, the presolar silicate abundance reaches 1 wt %, exceeding the total presolar grain abundance in meteorites by three orders of magnitude, where presolar silicates are still notably absent. The results to date support the idea that comets are rich in presolar materials, but are at odds with the common perception that they are 'pristine aggregates of interstellar grains'. These results underscore the scientific importance of sample return missions to comets. The technology for the analysis of micrometer-sized samples is well advanced. The newest generation of ion probe instruments allow for isotopic analyses at the submicrometer level. The nature of the organic matter is analyzed using Infrared and soft X-ray spectroscopy techniques on synchrotron-based instruments, also at the micrometer-scale and smaller. Electron microscopy and spectroscopy provide details on the mineralogy and chemistry of constituent grains in !DPs at nearly the atomic scale. Novel sample preparation techniques have been developed such that all of these measurements can now be made on the same 10 micrometer diameter particle. Returned comet samples captured in aerogel will pose new challenges in sample analysis, but should provide a major leap in our understanding of the fundamental building blocks of our Solar System

Austerity, political control and supplier selection in English local government: implications for autonomy in multi-level systems

Analysis of 60,000 contracts awarded by English councils between 2015-19 reveals that austerity constraints are a key predictor of councils outsourcing services to for-profit suppliers, regardless of their political control. Conservative Party-controlled councils are also more likely to contract with for-profit suppliers, although we found no link between Labour-controlled councils and not-for-profit suppliers, nor evidence that political or budgetary factors influence whether councils contract with providers based in their own region. We argue that centrally imposed funding cuts, and a belief that for-profit suppliers represent a cheaper option, could be overriding Labour Party councils’ ideological preference for not-for-profit providers

Measurement of Strength of Adhesive Bonds

In order to predict the strength of an adhesive bond between two metal sheets, it is necessary to measure the physical state of the adhesive layer that mechanically joins the two pieces of metal. This requires rapidly performing a detailed analysis of the ultrasonic echoes reflected from the entire structure when it is immersed in a water bath for a normal ultrasonic pulse-echo inspection. To achieve this result, computer-operated ultrasonic inspection systems have been assembled and equipped with special signal processing routines so that particular features of the ultrasonic echo in both the time domain and the frequency domain can be extracted in a time short enough to meet the requirements of a production inspection system. Such features as the relative amplitude of the signals reflected from the top and bottom of the adhesive layer and the frequencies for which standing waves are excited in the adhesive and in the metal adherends are of particular interest for making the strength predictions. It is also important that the interrogating ultrasonic pulse be of very short time duration so that the echoes from the various interfaces in the sandwich-like joint can be resolved in the time domain display. This requires the use of special high frequency pulse generators coupled to broad band transducers and amplifiers. Special procedures are also needed to insure the accuracy of the analog-to-digital conversion at the input to the computer and the subsequent transformations to and from the frequency domain