A Living Nightmare: A Phenomenological Study of Black Males\u27 Lived Experiences of Racial Profiling During Traffic Stops

For years, urban communities and specific ethnic groups within the US (mostly Blacks and Hispanics) have been targeted for racial profiling by our local police. Since the 1990’s, the outcry for justice by our Black and Hispanic communities increased the interests to find ways to address and fight against the act of racial profiling. This phenomenological study used a qualitative approach to collect information and gain the understanding and lived experiences of Black males between the ages of 20 – 49 who experienced racial profiling during routine traffic stops. Twelve Black Males between the ages of 20 to 49 were interviewed for the research study. Everyone was interviewed separately to gather experiences and meanings from their own points of view. In addition, 25 Black males within the same age group participated in a 1 hour focus group discussion. The information gathered from the interviews and focus group sessions were compiled into a Microsoft word transcript and reviewed and analyzed by the researcher to form seven themes. In order to come up with key findings, I isolated similar responses from the experiences shared by the research participants during the interviews and focus group session. In isolating some of the key responses revealed, I dissected racial profiling from a shared experience point of view based on common approaches practiced by law enforcement officers. The research study will contribute to field on conflict resolution through the voices of those who experienced racial profiling, and finding ways to encourage mediation through projecting the underlying concerns or issues to community leaders, government officials, concerned groups, and law enforcement agencies

The Lorentz Force and the Radiation Pressure of Light

In order to make plausible the idea that light exerts a pressure on matter, some introductory physics texts consider the force exerted by an electromagnetic wave on an electron. The argument as presented is both mathematically incorrect and has several serious conceptual difficulties without obvious resolution at the classical, yet alone introductory, level. We discuss these difficulties and propose an alternate demonstration.Comment: More or less as in AJ

Assessment of alternative strategies for sludge disposal into deep ocean basins off Southern California

The general framework of engineering alternatives for regional ocean sludge disposal is well described in a report by Raksit, and will not be repeated here. The various ocean disposal alternatives are less costly than all land-disposal and incineration/pyrolysis systems studied. Even though ocean sludge disposal is currently contrary to both state and federal regulations, it is hoped that this study will advance our scientific and engineering knowledge of the behavior and effects of sludge discharge in deep water, in case the regulatory policy is reexamined in the future. With this report we hope we have demonstrated the potential and difficulties of some new modeling techniques for predicting the effects of sludge discharge in the ocean. In the future. we believe it will be possible to formulate policy of ocean sludge discharges with much better case-by-case predictions of impacts for comparison with other alternatives (such as land disposal). not only for the Los Angeles/Orange County areas, but for all coastal urban areas

Simple ears inspire frequency agility in an engineered acoustic sensor system

Standard microphones and ultrasonic devices are generally designed with a static and flat frequency response in order to address multiple acoustic applications. However, they may not be flexible or adaptable enough to deal with some requirements. For instance, when operated in noisy environments such devices may be vulnerable to wideband background noise which will require further signal processing techniques to remove it, generally relying on digital processor units. In this work, we consider if microphones and ultrasonic devices could be designed to be sensitive only at selected frequencies of interest, whilst also providing flexibility in order to adapt to different signals of interest and to deal with environmental demands. This research exploits the concept where the “transducer becomes part of the signal processing chain” by exploring feedback processes between mechanical and electrical mechanisms that together can enhance peripheral sound processing. This capability is present within a biological acoustic system, namely in the ears of certain moths. That was used as the model of inspiration for a smart acoustic sensor system which provides dynamic adaptation of its frequency response with amplitude and time dependency according to the input signal of interest

Investigation of the Leak Response of a Carbon-Fiber Laminate Loaded in Biaxial Tension

Designers of pressurized structures have been reluctant to use composite materials because of concerns over leakage. Biaxial stress states are expected to be the worst-case loading condition for allowing leakage to occur through microcracks. To investigate the leakage behavior under in-plane biaxial loading, a cruciform composite specimen was designed that would have a relatively large test section with a uniform 1:1 biaxial loading ratio. A 7.6-cm-square test section was desired for future investigations of the leakage response as a result of impact damage. Many iterations of the cruciform specimen were evaluated using finite element analysis to reduce stress concentrations and maximize the size of the uniform biaxial strain field. The final design allowed the specimen to go to relatively high biaxial strain levels without incurring damage away from the test section. The specimen was designed and manufactured using carbon/epoxy fabric with a four-ply-thick, quasi-isotropic, central test section. Initial validation and testing were performed on a specimen without impact damage. The specimen was tested to maximum biaxial strains of approximately 4500micro epsilon without apparent damage. A leak measurement system containing a pressurized cavity was clamped to the test section and used to measure the flow rate through the specimen. The leakage behavior of the specimen was investigated for pressure differences up to 172 kP

A Finite Element Analysis for Predicting the Residual Compressive Strength of Impact-Damaged Sandwich Panels

A simple analysis method has been developed for predicting the residual compressive strength of impact-damaged sandwich panels. The method is tailored for honeycomb core-based sandwich specimens that exhibit an indentation growth failure mode under axial compressive loading, which is driven largely by the crushing behavior of the core material. The analysis method is in the form of a finite element model, where the impact-damaged facesheet is represented using shell elements and the core material is represented using spring elements, aligned in the thickness direction of the core. The nonlinear crush response of the core material used in the analysis is based on data from flatwise compression tests. A comparison with a previous analysis method and some experimental data shows good agreement with results from this new approach

3D printed small-scale acoustic metamaterials based on Helmholtz resonators with tuned overtones

Acoustic metamaterials have been extensively studied in recent decades due to their ability to control acoustic waves. In this paper, we present a prototype of a small-scale acoustic metamaterial based on Helmholtz resonators fabricated with additive manufacturing technology. The results confirm that 3D printed small-scale metamaterials can break the mass law by creating band gaps where the sound is deeply attenuated. We have also introduced a modification of the resonators whereby overtones are exploited and tuned in order to broaden the band gap. The output of this research could be used to provide passive filtering for transducers, to improve noise cancelling headphones, as well as in other smart acoustic sensors and IoT audio applications

Bio-inspired frequency agile acoustic system

Natural passive mechanical systems such as ear tympanic membranes may show active responses by incorporating feedback mechanisms which then affect their mechanical structure. In this paper, the moth’s auditory system is used as a biological model of inspiration. A smart acoustic system which alters its natural resonance frequency was developed. Experimental results, given by a proposed-built real-time embedded system, show time and amplitude dependency towards dynamic frequency adaptation according to the intensity of acoustic input signals