Effect of Surface Preparation Methods on Mechanical Properties of 3D Structures Fabricated by Stereolithography and 3D Printing for Electroless Ni Plating

Stereolithography (SL) and 3D Printing (3DP) are useful technologies for three-dimensional prototyping applications, providing highly accurate and detailed part geometries with high quality surface finishes. It is desired to improve the materials performance of the existing photocurable SL and 3DP resins for rapid tooling and other functional applications by applying a nickel (Ni) coating. In this work, surface preparation methods for electroless plating of commercial photopolymer resins such as NanoFormTM15120 (NanoForm) and Objet FullCure®840 (Veroblue) were explored in order to enhance the structural integrity of RP components. This study examined different surface preparation methods (chemical etching) and their effect on the surface morphology and mechanical strength of the polymers. It was observed that surface preparation of the resins significantly affected the mechanical properties and Ni plating of the substrate polymers. This is a critical step, since the Ni film takes on the surface structure of the substrate.Mechanical Engineerin

From Statehouse to Schoolhouse: Anti-Bullying Policy Efforts in U.S. States and School Districts

In 2011, 29.5 percent of U.S. public school districts didn't have anti-bullying policies, including many districts in states that require them, according to a report published by GLSEN. In states with such mandates, 26.3 percent of districts didn't have local policies. The report shows the gap that can emerge between the intentions of a law and the effectiveness of its implementation via policy and regulations

Evaluation of a Pound Net Leader Designed to Reduce Sea Turtle Bycatch

Offshore pound net leaders in the southern portion of Chesapeake Bay in Virginia waters were documented to incidentally take protected loggerhead, Caretta caretta, and Kemp’s ridley, Lepidochelys kempii, sea turtles. Because of these losses, NOAA’s National Marine Fisheries Service (NMFS) in 2004 closed the area to offshore pound net leaders annually from 6 May to 15 July and initiated a study of an experimental leader design that replaced the top two-thirds of the traditional mesh panel leader with vertical ropes (0.95 cm) spaced 61 cm apart. This experimental leader was tested on four pound net sites on the eastern shore of Chesapeake Bay in 2004 and 2005. During the 2 trial periods, 21 loggerhead and Kemp’s ridley sea turtles were found interacting with the control leader and 1 leatherback turtle, Dermochelys coriacea, was found interacting with the experimental leader. Results of a negative binomial regression analysis comparing the two leader designs found the experimental leader significantly reduced sea turtle interactions (p=0.03). Finfish were sampled from the pound nets in the study to assess finfish catch performance differences between the two leader designs. Although the conclusions from this element of the experiment are not robust, paired t-test and Wilcoxon signed rank test results determined no significant harvest weight difference between the two leaders. Kolmogorov-Smirnov tests did not reveal any substantive size selectivity differences between the two leaders

Integrated Navigation System: Not a Sum of Its Parts

Similar to the evolutionary process for living organisms, marine navigation systems are becoming increasingly complex and sophisticated. Both by design and function, shipboard and shore-based navigation systems are no longer individual equipment components operating independently. Instead, the trend is toward integration, data fusion and synergy. One example of this are new Performance Standards being considered by IMO to achieve a “harmonized” presentation of all navigation-related information on the display of an integrated navigation system (INS). Unlike a dedicated display for ECDIS or radar, the new INS displays will be a task-oriented composite presentations that enable the mariner to configure the display for an operational situation by selecting specific chart, radar, radar plotting aids (ARPA) and AIS information that is required for the task-at-hand. This paper gives a brief overview of the trend toward the development of INS. In addition to a brief summary of IMO performance standards for navigation equipment/systems, specific mention is made about a BSH (Germany) report on the “Functional Scope and Model of INS.” A discussion is provided about the challenges of providing navigation safety information that goes beyond traditional boundaries of products and services. Currently, many agencies continue to produce individual products and services on a component basis. Hydrographic offices grapple with trying to provide multiple products and services for paper charts, raster navigational charts (RNCs) and electronic navigational charts (ENCs) while a same time, Coast Guard and Maritime Safety agencies focus on improving Aids-to-Navigation (AtoN), Vessel Traffic Services (VTS), AIS networks -- and more recently, port security. In some respects, the continued concentration on separate products and services represents an organizational reluctance to change. This in turn, results in a fragmented, sub-optimal approach to the safety-of-navigation caused by the inability to provide mariners with “seamless” information at reasonable cost. In particular, hydrographic offices must be willing to recognize that chart information can no longer be considered to be separate, individual products. When it comes to the provision and use of chart-related information for use in an INS, the focus needs to shift to what information is actually desired, how it will be provided, what other information it will be used with, and whether it is truly up-todate

Product Focus versus Diversification: Estimates of X-Efficiency for the US Life Insurance Industry

Using data for the life insurance industry during 1990-1995, we empirically test for a relationship between a firm's output choice and measures of X-efficiency. Our empirical evidence suggests that diversification across multiple insurance and investment product lines resulted in greater X-efficiency than a more focused production strategy. The analysis in this article is consistent with the proposition that managers of multiproduct firms are able to achieve greater cost efficiencies than their counterparts in more focused firms by sharing inputs and efficiently allocating resources across product lines in response to changing industry conditions. Our findings are important since they justify the existence of multiproduct firms in the absence of cost complementarities and identify product diversification as a source of efficiency in the life insurance industry that should be recognized by managers, policyholders, and regulators.