\u27reel\u27 Gangs Or \u27real\u27 Gangs: A Qualitative Media Analysis Of Street Gangs Portrayed In Hollywood Films, 1960-2009

The purpose of this qualitative study is to explore the portrayals of street gangs as presented by a select sample of Hollywood films from 1960 to 2009. Using the theoretical framework of social constructionism and cinematic realism, a content analysis of 25 `street gang\u27 films was conducted to (a) determine the comparability of depictions of street gangs in Hollywood films with those characteristics of defining a street gang in the law enforcement and academic literature, (b) identify emergent themes and patterns, including changes over time, and (c) address the representations of realism in the portrayal of street gangs as depicted in films. The films used in the research were selected from a combination of three media sources: (1) references and discussions made about `street gang\u27 films from the literature, (2) media news reports on gang-related films, and (3) the online categorical lists of `street gang\u27 films created by Internet Movie Database (IMDb) and All Movie Guide (AMG). Based on the analysis of street gangs portrayed in Hollywood films, `reel\u27 street gangs resemble many of the characteristics that define `real\u27 street gangs as suggested by law enforcement officials and the academic literature. In addition, the emergent patterns and themes analyzed from the portrayal of `street gangs\u27 over a 50 year time-period reveal significant findings that provide a deeper understanding of the relationship between gangs and the media. First, there are changes in the portrayal of race/ethnicity since 1960. Second, street gangs are portrayed as both perpetrators and victims of violence and crime. Third, the producer/directors/writers employed efforts to create an `authentic\u27 or `realistic\u27 portrayal of street gangs. Lastly, the majority of the `street gang\u27 films analyzed in this study were in fact not about street gangs per se but rather used the film\u27s portrayal of street gangs as a vehicle to tell a broader and more compelling story concerning other universal themes. The findings lead to a rich understanding of social constructionism and the representations of street gangs in popular film. The implications of this research go beyond the official and academic portrayals of street gangs and to larger sociological implications of how street gangs are constructed in the media and the interpretations of those social constructions

Crack Roughness in the 2D Random Threshold Beam Model

We study the scaling of two-dimensional crack roughness using large scale beam lattice systems. Our results indicate that the crack roughness obtained using beam lattice systems does not exhibit anomalous scaling in sharp contrast to the simulation results obtained using scalar fuse lattices. The local and global roughness exponents ($\zeta_{loc}$ and $\zeta$, respectively) are equal to each other, and the two-dimensional crack roughness exponent is estimated to be $\zeta_{loc} = \zeta = 0.64 \pm 0.02$. Removal of overhangs (jumps) in the crack profiles eliminates even the minute differences between the local and global roughness exponents. Furthermore, removing these jumps in the crack profile completely eliminates the multiscaling observed in other studies. We find that the probability density distribution $p(\Delta h(\ell))$ of the height differences $\Delta h(\ell) = [h(x+\ell) - h(x)]$ of the crack profile obtained after removing the jumps in the profiles follows a Gaussian distribution even for small window sizes ($\ell$).Comment: 8 pages, 6 figure

Analytical, experimental and numerical study of a graded honeycomb structure under in-plane impact load with low velocity

Given the significance of energy absorption in various industries, light shock absorbers such as honeycomb structure under in-plane and out-of-plane loads have been in the core of attention. The purpose of this research is the analyses of graded honeycomb structure (GHS) behaviour under in-plane impact loading and its optimisation. Primarily, analytical equations for plateau stress and specific energy are represented, taking power hardening model (PHM) and elastic–perfectly plastic model (EPPM) into consideration. For the validation and comparison of acquired analytical equations, the energy absorption of a GHS made of five different aluminium grades is simulated in ABAQUS/CAE. In order to validate the numerical simulation method in ABAQUS, an experimental test has been conducted as the falling a weight with low velocity on a GHS. Numerical results retain an acceptable accordance with experimental ones with a 5.4% occurred error of reaction force. For a structure with a specific kinetic energy, the stress–strain diagram is achieved and compared with the analytical equations obtained. The maximum difference between the numerical and analytical plateau stresses for PHM is 10.58%. However, this value has been measured to be 38.78% for EPPM. In addition, the numerical value of absorbed energy is compared to that of analytical method for two material models. The maximum difference between the numerical and analytical absorbed energies for PHM model is 6.4%, while it retains the value of 48.08% for EPPM. Based on the conducted comparisons, the numerical and analytical results based on PHM are more congruent than EPPM results. Applying sequential quadratic programming method and genetic algorithm, the ratio of structure mass to the absorbed energy is minimised. According to the optimisation results, the structure capacity of absorbing energy increases by 18% compared to the primary model

Aerostructural Optimization of Nonplanar Lifting Surfaces

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/83557/1/AIAA-44727-830.pd

Modal decomposition of coupled instabilities: The method of the equivalent nodal forces

A solution to the ‘modal decomposition problem’ encountered within the context of the stability analysis of thin-walled structural members is presented. The proposed method achieves decomposition of a randomly deformed shape into a number of constituent modes, which have the physical meaning of the classical local, distortional and global buckling modes, augmented with two additional classes of shear and transverse extension modes. The basis vectors of these five classes are created by defining sets of nodal forces which, when applied to the member in a first order linear elastic problem, generate shapes commensurate with specific mechanical criteria defining the local, distortional, global, shear and transverse extension modes. In a second step the basis vectors of a given class are used to define a constrained stability problem, where the solution is restricted to a linear combination of these basis vectors, in order to obtain the buckled shapes under a given loading. The full set of buckling modes spanning the five classes forms an orthonormal basis of the complete deformation space. Consequently, decomposition can be achieved by projecting the shape which is to be decomposed onto the basis vectors. Two examples are provided to illustrate the method