Autonomous space processor for orbital debris

This work continues to develop advanced designs toward the ultimate goal of a GETAWAY SPECIAL to demonstrate economical removal of orbital debris utilizing local resources in orbit. The fundamental technical feasibility was demonstrated last year through theoretical calculations, quantitative computer animation, a solar focal point cutter, a robotic arm design and a subscale model. During this reporting period, several improvements are made in the solar cutter, such as auto track capabilities, better quality reflectors and a more versatile framework. The major advance has been in the design, fabrication and working demonstration of a ROBOTIC ARM that has several degrees of freedom. The functions were specifically tailored for the orbital debris handling. These advances are discussed here. Also a small fraction of the resources were allocated towards research in flame augmentation in SCRAMJETS for the NASP. Here, the fundamental advance was the attainment of Mach numbers up to 0.6 in the flame zone and a vastly improved injection system; the current work is expected to achieve supersonic combustion in the laboratory and an advanced monitoring system

Architecture and Agency For Equity In Areas Beyond National Jurisdiction

The United Nations (UN) Sustainable Development Goals (SDGs) and the UN Decade of Ocean Science for Sustainable Development (Ocean Decade) bring increased attention to various aspects of ocean governance, including equity. One of the Ocean Decade\u27s identified challenges is to develop a sustainable and equitable ocean economy, but questions arise about how to conceptualize the multiple dimensions of equity in an ocean context. These questions become more complex as activities move away from coastal ecosystems and communities into off-shore Areas Beyond National Jurisdiction (ABNJ), where ocean resources are recognized simultaneously as unowned/open access and as common heritage. In this paper, we mobilize the Earth System Governance analytics of ‘architecture’ and ‘agency’, to reflect on the possibilities for equity in ABNJ. Motivated by the general attention to equity in UN initiatives like the SDGs and the Ocean Decade, we describe current UN architecture for ocean governance, including principles that might support equity. Existing UN architecture focuses on distributional equity among nation states, with less attention to recognitional or procedural equity. State actors have most agency, while non-state actors can exercise some via broad UN declarations and through mechanisms like ‘major groups.’ We use on-going negotiations in the International Seabed Authority on rules for mineral exploitation and in the Intergovernmental Conference on an international legally binding instrument under UNCLOS on the conservation and sustainable use of marine biological diversity of Areas Beyond National Jurisdiction to illustrate how existing architecture shapes possibilities for equity in ABNJ. As new governance possibilities are imagined, attending to existing architecture and agency can help avoid further entrenching existing power imbalances and unwittingly reproducing or exacerbating inequities

Element Level Bridge Inspection: Benefits and Use of Data for Bridge Management

In 2012, Congress passed the Moving Ahead for Progress in the 21st Century Act (MAP-21) and committed to the development of a data-driven, risk based approach to asset management in the United States. This law requires the collection and submission of element level bridge inspection data for all National Highway System bridges, in addition to the National Bridge Inspection condition rating data. Ultimately, the data collected during element level bridge inspections should satisfy the requirements of the Federal Highway Administration and MAP-21 and be utilized by INDOT to evaluate bridge condition, predict deterioration, and guide decision making. The objective of this project is to develop recommendations for element level bridge inspection techniques, data collection, and inspector training based on a survey of INDOT peer agencies and a literature review of existing research and bridge inspection guidance. In order to collect consistent and reliable data, a rigorous inspector training program and detailed quality control procedures are necessary. INDOT must provide inspectors with the tools to be successful, including clearly defined expectations and instructions, comprehensive training and technical support, and effective inspection equipment. Similarly, robust quality control measures and periodic performance testing should be implemented to improve inspection quality and assess the agency’s performance

Experimental and Analytical Evaluation of the Strength of Selected Truss Members from the Approach Spans of the Winona Bridge

The following report details a research project comprised of two phases. Phase I included the full-scale experimental testing of two built-up truss chord members removed from service. The members were installed into a reaction frame and loaded to failure to determine remaining capacity in the presence of pack rust, as well as after-failure load redistribution behavior mimicking the member in a state following complete fracture of half the cross section. Phase I also included a finite element–based parametric study calibrated by the experimental work. The study was focused on two-channel axially loaded members for the purpose of developing closed-form solutions intended for evaluation of internal member redundancy. During Phase II of the project, a small round-robin-style inspection and load rating study was performed with certified bridge inspectors and practicing load rating engineers. The purpose was to investigate the variability in the inspection and evaluation of severely corroded steel tension members. This process evaluated two separate, but related, sources of variability within the inspection and load rating process. The variability in each task was controlled such that variability in the load ratings was not compounded by variability in the inspection findings

Probability of Detection Study for Visual Inspection of Steel Bridges: Volume 2—Full Project Report

An inspector’s ability to correctly identify surface and internal defects in steel bridge components is critical to protecting public safety. Ensuring that inspectors are properly trained and adequately equipped to detect these defects in locations that are difficult to access and/or in unfavorable environmental conditions must be a high priority. While the Federal Highway Administration and individual state departments of transportation have guidelines for inspector qualifications, trainings, and certifications, there is very little emphasis placed on evaluating or “testing: a given inspector’s capability to characterize defects in the field. As a result, there is also very little, if any, data on how well a given inspector actually performs or the variability which can be expected between inspectors. This comprehensive Probability of Detection (POD) study was conducted to establish the ability of an inspector with the current required training to locate and quantify cracks in steel bridge components. This study is believed to be the first statistically-significant study of its kind in the United States

Probability of Detection Study for Visual Inspection of Steel Bridges: Volume 1—Executive Summary

An inspector’s ability to correctly identify surface and internal defects in steel bridge components is critical to protecting public safety. Ensuring that inspectors are properly trained and adequately equipped to detect these defects in locations that are difficult to access and/or in unfavorable environmental conditions must be a high priority. While the Federal Highway Administration and individual state departments of transportation have guidelines for inspector qualifications, trainings, and certifications, there is very little emphasis placed on evaluating or “testing” a given inspector’s capability to characterize detect defects in the field. As a result, there is also very little if any data on how well a given inspector actually performs or the variability which can be expected between various inspectors. This comprehensive Probability of Detection (POD) study was conducted to establish the ability of an inspector with the current required training to locate cracks in steel bridge components using typical visual inspection techniques

A Simplified Approach for Designing SRMs in Composite Continuous Twin-Tub Girder Bridges

High torsional rigidity and attractive aesthetics in construction of twin-tub girder bridges make them preferable for the design of curved bridges. However, according to the concepts associated with the term “Fracture Critical (FC)” that are in place today, all two-girder bridges are classified as having FC members (FCMs) due to their perceived lack of load path redundancy. For a steel bridge with FCMs, the fracture of any of the FCMs is assumed to result in complete catastrophic failure or significant loss of serviceability; hence, every two years twin-tub girder bridges undergo very expensive hands-on field inspections. This report presents a simplified approach to ensure newly designed twin-tub girder bridges will meet all the requirements defined in the 2018 AASHTO Guide Specifications without performing in-depth FEA. AASHTO-ready proposed specifications are included in Appendix A. It is anticipated that these provisions could be incorporated into the AASHTO LRFD BDS as a new article 6.6.3 Special Provisions for Twin Tub Girder Bridges

Sustained Activation of Cell Adhesion Is a Differentially Regulated Process in B Lymphopoiesis

It is largely unknown how hematopoietic progenitors are positioned within specialized niches of the bone marrow microenvironment during development. Chemokines such as CXCL12, previously called stromal cell–derived factor 1, are known to activate cell integrins of circulating leukocytes resulting in transient adhesion before extravasation into tissues. However, this short-term effect does not explain the mechanism by which progenitor cells are retained for prolonged periods in the bone marrow. Here we show that in human bone marrow CXCL12 triggers a sustained adhesion response specifically in progenitor (pro- and pre-) B cells. This sustained adhesion diminishes during B cell maturation in the bone marrow and, strikingly, is absent in circulating mature B cells, which exhibit only transient CXCL12-induced adhesion. The duration of adhesion is tightly correlated with CXCL12-induced activation of focal adhesion kinase (FAK), a known molecule involved in integrin-mediated signaling. Sustained adhesion of progenitor B cells is associated with prolonged FAK activation, whereas transient adhesion in circulating B cells is associated with short-lived FAK activation. Moreover, sustained and transient adhesion responses are differentially affected by pharmacological inhibitors of protein kinase C and phosphatidylinositol 3-kinase. These results provide a developmental cell stage–specific mechanism by which chemokines orchestrate hematopoiesis through sustained rather than transient activation of adhesion and cell survival pathways

Interaction of CarD with RNA polymerase mediates Mycobacterium tuberculosis viability, rifampin resistance, and pathogenesis

Mycobacterium tuberculosis infection continues to cause substantial human suffering. New chemotherapeutic strategies, which require insight into the pathways essential for M. tuberculosis pathogenesis, are imperative. We previously reported that depletion of the CarD protein in mycobacteria compromises viability, resistance to oxidative stress and fluoroquinolones, and pathogenesis. CarD associates with the RNA polymerase (RNAP), but it has been unknown which of the diverse functions of CarD are mediated through the RNAP; this question must be answered to understand the CarD mechanism of action. Herein, we describe the interaction between the M. tuberculosis CarD and the RNAP β subunit and identify point mutations that weaken this interaction. The characterization of mycobacterial strains with attenuated CarD/RNAP β interactions demonstrates that the CarD/RNAP β association is required for viability and resistance to oxidative stress but not for fluoroquinolone resistance. Weakening the CarD/RNAP β interaction also increases the sensitivity of mycobacteria to rifampin and streptomycin. Surprisingly, depletion of the CarD protein did not affect sensitivity to rifampin. These findings define the CarD/RNAP interaction as a new target for chemotherapeutic intervention that could also improve the efficacy of rifampin treatment of tuberculosis. In addition, our data demonstrate that weakening the CarD/RNAP β interaction does not completely phenocopy the depletion of CarD and support the existence of functions for CarD independent of direct RNAP binding

Effects of increasing the affinity of CarD for RNA polymerase on Mycobacterium tuberculosis growth, rRNA transcription, and virulence

CarD is an essential RNA polymerase (RNAP) interacting protein in Mycobacterium tuberculosis that stimulates formation of RNAP-promoter open complexes. CarD plays a complex role in M. tuberculosis growth and virulence that is not fully understood. Therefore, to gain further insight into the role of CarD in M. tuberculosis growth and virulence, we determined the effect of increasing the affinity of CarD for RNAP. Using site-directed mutagenesis guided by crystal structures of CarD bound to RNAP, we identified amino acid substitutions that increase the affinity of CarD for RNAP. Using these substitutions, we show that increasing the affinity of CarD for RNAP increases the stability of the CarD protein in M. tuberculosis. In addition, we show that increasing the affinity of CarD for RNAP increases the growth rate in M. tuberculosis without affecting 16S rRNA levels. We further show that increasing the affinity of CarD for RNAP reduces M. tuberculosis virulence in a mouse model of infection despite the improved growth rate in vitro. Our findings suggest that the CarD-RNAP interaction protects CarD from proteolytic degradation in M. tuberculosis, establish that growth rate and rRNA levels can be uncoupled in M. tuberculosis and demonstrate that the strength of the CarD-RNAP interaction has been finely tuned to optimize virulence. IMPORTANCE Mycobacterium tuberculosis, the causative agent of tuberculosis, remains a major global health problem. In order to develop new strategies to battle this pathogen, we must gain a better understanding of the molecular processes involved in its survival and pathogenesis. We have previously identified CarD as an essential transcriptional regulator in mycobacteria. In this study, we detail the effects of increasing the affinity of CarD for RNAP on transcriptional regulation, CarD protein stability, and virulence. These studies expand our understanding of the global transcription regulator CarD, provide insight into how CarD activity is regulated, and broaden our understanding of prokaryotic transcription