Cultivating Food Justice: Exploring Public Interest Design Process through a Food Security & Sustainability Hub

This thesis addresses the deep-rooted systemic issue of food justice, through the development of a Food Security & Sustainability Hub in Northampton, Massachusetts. As part of the thesis process, I initiated engagement with local stakeholders and organizations using established practices of public interest design. This included a series of meetings and site visits with the leaders of a nonprofit social justice farm in Northampton, MA. These conversations shaped the project scope and design. In doing so, the thesis project tested ideas about social process and the overarching role of discourse in design. My hope is that through thoughtful analysis and engagement through the lens of a real project, I can contribute to this ongoing conversation and inform future pursuits

IMECE2005-82282 CONTROL OF CYLINDRICAL SHELL PANELS WITH INPUT SHAPING AND PHASE SHIFT OF SHAPE MEMORY RING SEGMENTS

ABSTRACT The purpose of this study is to investigate the control effect from shape memory alloy (SMA) ring segments placed at the desired positions along the length of a cylindrical shell panel. Equations of motion for an elastic cylindrical shell panel are defined first and then used with the assumed mode shape functions for the appropriate boundary conditions in a free vibration analysis. The results from this are used with the generic shell sensing equation to determine the spatial strain distribution. From this, optimal placement of ring segments for each given mnth mode is determined. Through use of the modal expansion method, the open-loop control force induced by the SMA ring segments applied to a cylindrical shell panel is determined next. This evaluation shows that only the odd modes in the circumferential direction can be controlled. Longitudinal modes are controlled via placing a varying number, depending on the mode, of ring segments along the length of the cylindrical shell panel. To predict control effects of the SMA ring segments, the modal participation factor response is determined for an external harmonic excitation applied to the shell along with SMA control force induced to eliminate the unwanted effects. The results show that with proper choice of waveform function for the applied temperature to the SMA ring segments and minor modifications to frequency and phase, the SMA ring segments can control unwanted external vibration

LX-17 Deflagration at High Pressures and Temperatures

We measure the laminar deflagration rate of LX-17 (92.5 wt% TATB, 7.5 wt% Kel-F 800) at high pressure and temperature in a strand burner, thereby obtaining reaction rate data for prediction of thermal explosion violence. Simultaneous measurements of flame front time-of-arrival and temporal pressure history allow for the direct calculation of deflagration rate as a function of pressure. Additionally, deflagrating surface areas are calculated in order to provide quantitative insight into the dynamic surface structure during deflagration and its relationship to explosion violence. Deflagration rate data show that LX-17 burns in a smooth fashion at ambient temperature and is represented by the burn rate equation B = 0.2P{sup 0.9}. At 225 C, deflagration is more rapid and erratic. Dynamic deflagrating surface area calculations show that ambient temperature LX-17 deflagrating surface areas remain near unity over the pressure range studied

Sex differences in knee loading in recreational runners

Patellofemoral pain is the most common chronic pathology in recreational runners. Female runners are at greater risk of developing patellofemoral pain, although the exact mechanism behind this is not fully understood. This study aimed to determine whether female recreational runners exhibit distinct knee loading compared to males. Fifteen males and 15 females recreational runners underwent 3D running analysis at 4.0 m s−1±5%. Sagittal/coronal joint moments, patellofemoral contact forces (PTF) and pressures (PCP) were compared between sexes. The results show that females exhibited significantly greater knee extension (p<0.008, pη2=0.27: males=3.04; females=3.47 N m kg−1) and abduction (p<0.008, pη2=0.28: males=0.54; females=0.82 N m kg−1) moments as well as PTF (p<0.008, pη2=0.29: males=3.25; females=3.84 B.W.) and PCP (p<0.008, pη2=0.26: males=7.96; females=9.27 MPa) compared to males. Given the proposed relationship between knee joint loading and patellofemoral pathology, the current investigation provides insight into the incidence of patellofemoral pain in females

Thermal Damage on LX-04 Mock Material and Gas Permeability Assessment

RM-04-BR, a mock material for the plastic-bonded HMX-based explosive LX-04, is characterized after being thermally damaged at 140 C and 190 C. We measured the following material properties before and after the thermal experiments: sample volume, density, sound speed, and gas permeability in the material. Thermal treatment of the mock material leads to de-coloring and insignificant weight loss. Sample expanded, resulting in density reductions of 1.0% to 2.5% at 140 C and 190 C, respectively. Permeability in the mock samples was found to increase from 10{sup -15} to 10{sup -16} m{sup 2}, as the porosity increased. The permeability measurements are well represented by the Blake-Kozeny equation for laminar flow through porous media. The results are similar to the gas permeability in PBX-9501 obtained by other researchers

Some dare call it conspiracy:Labeling something a conspiracy theory does not reduce belief in it.

“Conspiracy theory” is widely acknowledged to be a loaded term. Politicians use it to mock and dismiss allegations against them, while philosophers and political scientists warn that it could be used as a rhetorical weapon to pathologize dissent. In two empirical studies conducted on Amazon Mechanical Turk, I present an initial examination of whether this concern is justified. In Experiment 1, 150 participants judged a list of historical and speculative theories to be no less likely when they were labeled “conspiracy theories” than when they were labeled “ideas.” In Experiment 2 (N5802), participants who read a news article about fictitious “corruption allegations” endorsed those allegations no more than participants who saw them labeled “conspiracy theories.” The lack of an effect of the conspiracy-theory label in both experiments was unexpected and may be due to a romanticized image of conspiracy theories in popular media or a dilution of the term to include mundane speculation regarding corruption and political intrigue

ALE3D Simulation and Measurement of Violence in a Fast Cookoff Experiment for LX-10

Fast cookoff is of interest in the areas of fire hazard reduction and the development of directed energy systems for defense. During a fast cookoff (thermal explosion), high heat fluxes cause rapid temperature increases and ignition in thin boundary layers. We are developing ALE3D models to describe the thermal, chemical, and mechanical behavior during the heating, ignition, and explosive phases. The candidate models and numerical strategies are being evaluated using benchmark cookoff experiments. Fast cookoff measurements were made in a Scaled-Thermal-Explosion-eXperiment (STEX) for LX-10 (94.7% HMX, 5.3% Viton A) confined in a 4130 steel tube with reinforced end caps. Gaps were present at the side and top of the explosive charge to allow for thermal expansion. The explosive was heated until explosion using radiant heaters. Temperatures were measured using thermocouples positioned on the tube wall and in the explosive. During the explosion, the tube expansion and fragment velocities were measured with strain gauges, Photonic-Doppler-Velocimeters (PDVs), and micropower radar units. A fragment size distribution was constructed from fragments captured in Lexan panels. ALE3D models for chemical, thermal, and mechanical behavior were developed for the heating and explosive processes. A multi-step chemical kinetics model is employed for the HMX while a one-step model is used for the Viton. A pressure-dependent deflagration model is employed during the expansion. A Steinberg-Guinan model represents the mechanical behavior of the solid constituents while polynomial and gamma-law expressions are used for the equation of state of the solid and gas species, respectively. Parameters for the kinetics model were specified using measurements of the One-Dimensional-Time-to-Explosion (ODTX), while measurements for burn rate were employed to determine parameters in the burn front model. The simulations include radiative and conductive transport across the dynamic gaps between the explosive charge and metal case. Model results are compared to measurements for the temperature fields, time to explosion, and wall expansion rates

CHARACTERIZATION OF DAMAGED MATERIALS

Thermal damage experiments were conducted on LX-04, LX-10, and LX-17 at high temperatures. Both pristine and damaged samples were characterized for their material properties. A pycnometer was used to determine sample true density and porosity. Gas permeability was measured in a newly procured system (diffusion permeameter). Burn rate was measured in the LLNL strand burner. Weight losses upon thermal exposure were insignificant. Damaged pressed parts expanded, resulting in a reduction of bulk density by up to 10%. Both gas permeabilities and burn rates of the damaged samples increased by several orders of magnitude due to higher porosity and lower density. Moduli of the damaged materials decreased significantly, an indication that the materials became weaker mechanically. Damaged materials were more sensitive to shock initiation at high temperatures. No significant sensitization was observed when the damaged samples were tested at room temperature

Unmanned Aircraft Systems Detect and Avoid System: End-to-End Verification and Validation Simulation Study of Minimum Operations Performance Standards for Integrating Unmanned Aircraft into the National Airspace System

As Unmanned Aircraft Systems (UAS) make their way to mainstream aviation operations within the National Airspace System (NAS), research efforts are underway to develop a safe and effective environment for their integration into the NAS. Detect and Avoid (DAA) systems are required to account for the lack of "eyes in the sky" due to having no human on-board the aircraft. The technique, results, and lessons learned from a detailed End-to-End Verification and Validation (E2-V2) simulation study of a DAA system representative of RTCA SC-228's proposed Phase I DAA Minimum Operational Performance Standards (MOPS), based on specific test vectors and encounter cases, will be presented in this paper