Electrical termination techniques

A technical review of high reliability electrical terminations for electronic equipment was made. Seven techniques were selected from this review for further investigation, experimental work, and preliminary testing. From the preliminary test results, four techniques were selected for final testing and evaluation. These four were: (1) induction soldering, (2) wire wrap, (3) percussive arc welding, and (4) resistance welding. Of these four, induction soldering was selected as the best technique in terms of minimizing operator errors, controlling temperature and time, minimizing joint contamination, and ultimately producing a reliable, uniform, and reusable electrical termination

Survey and Experimental Testing of Nongravimetric Mass Measurement Devices

Documentation presented describes the design, testing, and evaluation of an accelerated gravimetric balance, a low mass air bearing oscillator of the spring-mass type, and a centrifugal device for liquid mass measurement. A direct mass readout method was developed to replace the oscillation period readout method which required manual calculations to determine mass. A protoype 25 gram capacity micro mass measurement device was developed and tested

Technology and Regional Development in the American Context

Many large cities in the developed countries have recently experienced a slow-down of growth, and in some cases, absolute contraction of their population size. These trends pertain in particular to old industrial agglomerations which often fail to adapt to the changing demands and locational requirements of modern production facilities and to differentiate their employment structure. Interrelations between industrial restructuring and urban regional change were among topics studied in the former Human Settlements and Services Area at IIASA. They are also of current research interest to the Regional and Urban Development Group. The paper by J. Rees, H. Stafford, R. Briggs and R. Oakey touches on several aspects of those interdependencies, especially the question of how do high-technology complexes develop over space. Part II of the paper has been done within a framework of an international collaboration project involving similar studies in the U.K. and F.R.G. and coordinated by Professor John Goddard of Newcastle, U.K

Thermobaric control of gravitational potential energy generation by diapycnal mixing in the deep ocean

Sources and sinks of gravitational potential energy (GPE) play a rate-limiting role in the large scale ocean circulation. A key source is turbulent diapycnal mixing, whereby irre- versible mixing across isoneutral surfaces is enhanced by turbulent straining of these surfaces. This has motivated international observational efforts to map diapycnal mixing in the global ocean. However, in order to accurately relate the GPE supplied to the large scale circulation by diapycnal mixing to the mixing energy source, it is first necessary to determine the ratio, ξ , of the GPE generation rate to the available potential energy dissipation rate associated with turbulent mixing. Here, the link between GPE and hydro- static pressure is used to derive the GPE budget for a com- pressible ocean with a nonlinear equation of state. The role of diapycnal mixing is isolated and from this a global cli- matological distribution of ξ is calculated. It is shown that, for a given source of mixing energy, typically three times as much GPE is generated if the mixing takes place in bottom waters rather than in the pycnocline. This is due to GPE destruction by cabbelling in the pycnocline, as opposed to thermobaric enhancement of GPE generation by diapycnal mixing in the deep ocean

Measuring lateral heat flux across a thermohaline front: A model and observational test

We develop and test a method to observationally estimate lateral intrusive heat flux across a front. The model combines that of Joyce (1977), in which lateral cross-frontal advection by intrusions creates vertical temperature gradients, and Osborn and Cox (1972) in which vertical mixing of those gradients creates thermal microstructure that is dissipated by molecular conduction of heat. Observations of thermal microstructure dissipation χT are then used to estimate the production by intrusions, and hence the lateral heat flux and diffusivity. This method does not depend on the precise mechanism(s) of mixing, or on the dynamical mechanisms driving the frontal intrusions. It relies on several assumptions: (1) lateral cross-frontal advection produces diapycnal temperature gradients that are mixed locally, (2) thermal variance is dissipated locally and not exported, (3) intrusion scales are larger than turbulence scales, and (4) isotropy of temperature microstructure is assumed in order to estimate χT.The method is tested using microstructure observations in Meddy Sharon, where the erosion rate and associated lateral heat flux are known from successive mesoscale hydrographic observations (Hebert et al., 1990). An expression is developed for the production (lateral heat flux times lateral temperature gradient, expected to equal χT) in a front of steady shape that is eroding (detraining) at a steady rate; the production is proportional to the erosion speed and the square of the cross-frontal temperature contrast, both of which are well-known from observations. The qualitative structure and integrated value of the dissipation agree well with model assumptions and predictions: thermal variance produced by lateral intrusive heat flux is dissipated locally, dissipation in intrusive regions dominates total dissipation, and the total dissipation agrees with the observed erosion rate, all of which suggests that microstructure observations can be used to estimate intrusive heat flux. A direct comparison was made between lateral heat flux estimated from mesoscale Meddy structure plus the known rate of erosion, and lateral flux based on microscale temperature dissipation, with excellent agreement in the frontal zone and poorer agreement where lateral temperature gradient is too small to accurately measure

Το λογισμικό SpatialAnalyzer & εφαρμογές του σε προβλήματα βιομηχανικής γεωδαισίας

This paper reports a first study exploring genomic prediction for adaptation of sorghum [Sorghum bicolor (L.) Moench] to drought-stress (D-ET) and nonstress (W-ET) environment types. The objective was to evaluate the impact of both modeling genotype × environment interaction (G×E) and accounting for heterogeneous variances of marker effects on genomic prediction of parental breeding values for grain yield within and across environment types (ETs). For this aim, different genetic covariance structures and different weights for individual markers were investigated in best linear unbiased prediction (BLUP)-based prediction models. The BLUP models used a kinship matrix combining pedigree and genomic information, termed K-BLUP. The dataset comprised testcross yield performances under D-ET and W-ET as well as pedigree and genomic data. In general, modeling G×E increased predictive ability and reduced empirical bias of genomic predictions for broad adaptation across both ETs vs. models that ignored G×E by fitting a main genetic effect only. Genomic predictions for specific adaptation to D-ET or W-ET were also improved by K-BLUP models that explicitly accommodated G×E and used data from both ETs relative to prediction models that used data from the targeted ET exclusively or models that used all the data but assumed no G×E. Allowing for heterogeneous marker variances through weighted K-BLUP produced clear increments (43–72%) in predictive ability of genomic prediction for grain yield in all adaptation scenarios. We conclude that G×E as well as locus-specific genetic variances should be accommodated in genomic prediction models to improve adaptability of sorghum to variable environmental conditions

Vigorous lateral export of the meltwater outflow from beneath an Antarctic ice shelf

The instability and accelerated melting of the Antarctic Ice Sheet are among the foremost elements of contemporary global climate change1, 2. The increased freshwater output from Antarctica is important in determining sea level rise1, the fate of Antarctic sea ice and its effect on the Earth’s albedo4, 5, ongoing changes in global deep-ocean ventilation6, and the evolution of Southern Ocean ecosystems and carbon cycling7, 8. A key uncertainty in assessing and predicting the impacts of Antarctic Ice Sheet melting concerns the vertical distribution of the exported meltwater. This is usually represented by climate-scale models3–5, 9 as a near-surface freshwater input to the ocean, yet measurements around Antarctica reveal the meltwater to be concentrated at deeper levels10, 11, 12, 13, 14. Here we use observations of the turbulent properties of the meltwater outflows from beneath a rapidly melting Antarctic ice shelf to identify the mechanism responsible for the depth of the meltwater. We show that the initial ascent of the meltwater outflow from the ice shelf cavity triggers a centrifugal overturning instability that grows by extracting kinetic energy from the lateral shear of the background oceanic flow. The instability promotes vigorous lateral export, rapid dilution by turbulent mixing, and finally settling of meltwater at depth. We use an idealized ocean circulation model to show that this mechanism is relevant to a broad spectrum of Antarctic ice shelves. Our findings demonstrate that the mechanism producing meltwater at depth is a dynamically robust feature of Antarctic melting that should be incorporated into climate-scale models

The impact of digital start-up founders’ higher education on reaching equity investment milestones

This paper builds on human capital theory to assess the importance of formal education among graduate entrepreneurs. Using a sample of 4.953 digital start-ups the paper evaluates the impact of start-up founding teams’ higher education on the probability of securing equity investment and subsequent exit for investors. The main findings are: (1), teams with a founder that has a technical education are less likely to remain self-financed and are more likely to secure equity investment and to exit, but the impact of technical education declines with higher level degrees, (2) teams with a founder that has doctoral level business education are less likely to remain self-financed and have a higher probability of securing equity investment, while undergraduate and postgraduate business education have no significant effect, and (3) teams with a founder that has an undergraduate general education (arts and humanities) are less likely to remain self-financed and are more likely to secure equity investment and exit while postgraduate and doctoral general education have no significant effect on securing equity investment and exit. The findings enhance our understanding of factors that influence digital start-ups achieving equity milestones by showing the heterogeneous influence of different types of higher education, and therefore human capital, on new ventures achieving equity milestones. The results suggest that researchers and policy-makers should extend their consideration of universities entrepreneurial activity to include the development of human capital