Documenting the Unauthorized: Political Responses to Unauthorized Immigration

Cultural prejudice rather than self interest is the conventional wisdom for why voters respond negatively to immigration. Using a new measure of unauthorized immigrants based on self-reported invalid social security numbers, we show that voters' responses are more nuanced than mere prejudice against minorities. Using county level data from the U.S. state of Georgia, we find that voters in counties with above median levels of unauthorized workers are more likely to support the Republican party. We also find that wealthier counties and wealthier voters are most likely to respond negatively to the unauthorized. Our evidence warns against arguments that depict opposition to immigration as motivated solely by xenophobia and cultural fears among lower income whites

Experimental investigation of cracking localization in RC beams with steel fibers

This article presents an experimental study aimed to identify and quantify the cracking localization (CL) phenomenon in under-reinforced R/SFRC beams. Results of current experiments together with those of previous tests published by the authors were used for quantification of the cracking localization level (CLL) considering the effect of fiber content, V-f, and of longitudinal reinforcement ratio, rho (s), over a wide range of rho (s) and the effect of rebar yield and ultimate strengths. The experimental program consisted of four-point bending tests of normal strength R/SFRC beam specimens with 400 and 500-MPa steel and fiber volumetric contents V-f of 0.5 and 0.76%. A new definition is introduced for "significantly wide cracks" that yields a unique definition of the CLL when this phenomenon diminishes. Moreover, it is now proposed to change the definition of CLL. The study identified the existence of a transition point (TP), beyond which addition of fibers to the concrete mix do not affect CLL anymore. Observations from the experimental results prove the consistency of the newly proposed CLL definitions as well as the dependency of CL on both the amount and stress hardening of the tension steel. Their use enables a clear delineation of the CL phenomenon in R/SFRC beams. The importance of this finding refers to the reported decrease of flexural ductility in R/SFRC beams due to high CLL. Hence, the importance of the ability, achieved in the current findings, to quantify the conditions for TPs in various cases

Effect of width of geosynthetic reinforcement within the granular cover on the load distribution over the tunnel lining

A realistic estimation of load distribution over the buried structures is necessary for proper analysis of tunnels, culverts and pipes/conduits. Tunnels with linings are often constructed in transportation and hydraulic engineering. For the design of tunnel lining, it is essential to know the load over the lining. Load distribution over the buried structures has been investigated scientifically during the past several decades. The method of investigation includes experimental, numerical and analytical methods. The finite-element models based on some commercial software have been developed for load analyses for design of the tunnel linings and buried structures. The geosynthetic is an effective reinforcement layer to reduce the load over the buried structure. Although some studies have indicated that the geosynthetic layer can reduce the load over the buried structure, but no attempt has been made to determine the optimal width of the geosynthetic reinforcement within the granular cover. Therefore, in this paper, an attempt is made to present effect of width of geosynthetic layer on the load distribution over the tunnel lining. The study has been carried out by developing a numerical model of the problem. The commercial software PLAXIS 2D has been used for numerical modelling. The results have been presented in the form of design charts, mentioning the optimum width of geosynthetic layer, so that they can be used by practising engineers