Lehigh University

About: Lehigh University is a education organization based out in Bethlehem, Pennsylvania, United States. It is known for research contribution in the topics: Catalysis & Fracture mechanics. The organization has 12684 authors who have published 26550 publications receiving 770061 citations.

Flexural Strength of Steel-Concrete Composite Beams

Abstract: Tests on twelve single span and one two-span continuous, full scale composite beams are described, and the results evaluated. The investigation was concerned with determining the minimum number of shear connectors required for steel and concrete composite beams in buildings. A thorough examination of the ultimate strength of members was made. A criterion for the minimum shear connector requirement was derived based on the ultimate strength of the members. Relationships between the ultimate strengths of commonly used types of mechanical shear connectors and the ultimate strength of a composite beam are developed. The deflection of members is shown to be larger for beams with the minimum recommended shear connection as compared to theoretical bending deflections, and the magnitude of these deflections is discussed.

Synthesis and surface properties of environmentally responsive segmented polyurethanes.

Abstract: Polyurethanes, containing well-defined assemblies of perfluoro-polyether (PFPE or hexafluoropropene oxide oligomer), polydimethylsiloxane (PDMS), and polyethylene glycol (PEG) segments, exhibit oleophobic, hydrophobic, and hydrophilic properties in response to the polarity of the contacting medium. These polymers were prepared by reacting hydroxy(polyethyleneoxy)-propylether-terminated PDMS block copolymer (HO-PEG-PDMS-PEG-OH) with 4,4'-methylene-bis(phenylene isocyanate) (MDI) in the presence of dibutyltin dilaurate catalyst, followed by reaction with 1,2-diol functional PFPE and chain extension with 2,2,3,3-tetrafluoro-1,4-butanediol (FB). The oleophobic and hydrophobic properties of the segmented polyurethanes (SPU) are due to the segregation of PFPE segments at the polymer-air interface. Wettability studies revealed that the same surface becomes hydrophilic, presumably due to the segregation of the PEG segments at the polymer-water interface. This hydrophobic-to-hydrophilic transformation of the surface prevails not only when the polymer is in contact with liquid water but with water vapor as well. The understanding of the reconstruction mechanism of this novel family of SPU surfaces would furnish valuable information for various applications where dynamic transformation of surface activity is desired.

Do Auditors Price Audit Committee's Expertise? The Case of Accounting versus Nonaccounting Financial Experts

Abstract: The issue of whether audit pricing reflects the effectiveness of the audit committee is of fundamental interest to auditors, managers, and others. Auditors are expected to price the effectiveness o...