The Shadow Moiré method using the phase shifting technique and digital image processing: computational implementation and application to the 3D-reconstruction of a buckled plate

The Shadow Moiré fringe patterns are level lines of equal depth generated by interference between a master grid and its shadow projected on the surface. In simplistic approach, the minimum error is about the order of the master grid pitch, that is, always larger than 0,1 mm, resulting in an experimental technique of low precision. The use of a phase shift increases the accuracy of the Shadow Moiré technique. The current work uses the phase shifting method to determine the surfaces three-dimensional shape using isothamic fringe patterns and digital image processing. The current study presents the method and applies it to images obtained by simulation for error evaluation, as well as to a buckled plate, obtaining excellent results. The method hands itself particularly useful to decrease the errors in the interpretation of the Moiré fringes that can adversely affect the calculations of displacements in pieces containing many concave and convex regions in relatively small areas.

Characterization of Non-linear Polymer Properties to Predict Process Induced Warpage and Residual Stress of Electronic Packages

Nonlinear thermo-mechanical properties of advanced polymers are crucial to accurate prediction of the process induced warpage and residual stress of electronics packages. The Fiber Bragg grating (FBG) sensor based method is advanced and implemented to determine temperature and time dependent nonlinear properties. The FBG sensor is embedded in the center of the cylindrical specimen, which deforms together with the specimen. The strains of the specimen at different loading conditions are monitored by the FBG sensor. Two main sources of the warpage are considered: curing induced warpage and coefficient of thermal expansion (CTE) mismatch induced warpage. The effective chemical shrinkage and the equilibrium modulus are needed for the curing induced warpage prediction. Considering various polymeric materials used in microelectronic packages, unique curing setups and procedures are developed for elastomers (extremely low modulus, medium viscosity, room temperature curing), underfill materials (medium modulus, low viscosity, high temperature curing), and epoxy molding compound (EMC: high modulus, high viscosity, high temperature pressure curing), most notably, (1) zero-constraint mold for elastomers; (2) a two-stage curing procedure for underfill materials and (3) an air-cylinder based novel setup for EMC. For the CTE mismatch induced warpage, the temperature dependent CTE and the comprehensive viscoelastic properties are measured. The cured cylindrical specimen with a FBG sensor embedded in the center is further used for viscoelastic property measurements. A uni-axial compressive loading is applied to the specimen to measure the time dependent Young’s modulus. The test is repeated from room temperature to the reflow temperature to capture the time-temperature dependent Young’s modulus. A separate high pressure system is developed for the bulk modulus measurement. The time temperature dependent bulk modulus is measured at the same temperatures as the Young’s modulus. The master curve of the Young’s modulus and bulk modulus of the EMC is created and a single set of the shift factors is determined from the time temperature superposition. The supplementary experiments are conducted to verify the validity of the assumptions associated with the linear viscoelasticity. The measured time-temperature dependent properties are further verified by a shadow moiré and Twyman/Green test.

Finding gold in our shadow: psychotherapy and the shadow syndrome

Drawing on the work of Carl Jung and Robert Bly, Yaro Starak explores how 'shadow work' can be used within a Gestalt group therapy environment to uncover the 'gold in our shadow bags' - hidden inner strengths and resources that we were previously unaware of that may lead to healing and transformation. (editor abstract)

In the Shadow of Power

Pedro Feytor Pinto headed the Department of Information Services (SEIT) in the government of Marcello Caetano who replaced Antonio Oliveira Salazar in 1968 as the head of the Portuguese government. Feytor Pinto has just released a book entitled Na Sombra do Poder (In the Shadow of Power)[Lisboa, D. Quixote, 2011, pp. 402]. Not wishing to classify it as history or memoirs, yet hoping that historians may find it useful, the author chooses to narrate events as he experienced them from his vantage point in the shadow of Power, during the years ending with the Carnation Revolt of 25 April 1974, which put an end to half a century of dictatorship, known as Estado Novo.

Merle's Shadow

Combined media on photographic paper. 61½" x 53" Private Collection

Does the EU financing system contribute to shadow economic activity?

Financial contributions to the EU budget depend basically on official GDP. This means that countries with higher shadow economic activity contribute less than they should contribute in a system based on actual GDP and therefore could reduce their incentive to fight against such activities. In this paper we investigate if the EU financing system really has an influence on the intensity with which governments in EU member states fight against shadow economic activity. We find that the EU net contributors significantly fight more intensively against shadow economic activity while EU net receivers significantly fight less. As a result, shadow economic activity is higher in net receiver and lower in net contributor countries than it were in comparison with a scenario of nationally balanced EU funding. Quantitatively and averaged over the time period 2001-2007, the diagnosed effect amounts to a stimulation of hidden economic activity by almost 10% for particular economies. JEL classification: C31, D63, F33, H21, H26. Keywords: EU financing system, shadow economy, tax auditing.

A model of shadow banking

We present a model of shadow banking in which financial intermediaries originate and trade loans, assemble these loans into diversified portfolios, and then finance these portfolios externally with riskless debt. In this model: i) outside investor wealth drives the demand for riskless debt and indirectly for securitization, ii) intermediary assets and leverage move together as in Adrian and Shin (2010), and iii) intermediaries increase their exposure to systematic risk as they reduce their idiosyncratic risk through diversification, as in Acharya, Schnabl, and Suarez (2010). Under rational expectations, the shadow banking system is stable and improves welfare. When investors and intermediaries neglect tail risks, however, the expansion of risky lending and the concentration of risks in the intermediaries create financial fragility and fluctuations in liquidity over time.