Understanding how root traits vary within and among species, and how they respond to heterogeneous environments, can provide important insight into functional plant attributes that influence plant survival in competitive environments. Selecting plant material with root traits that will support its survival in competitive environments may help improve the outcomes...
Attitude control in quadrotor Unmanned Aerial Vehicle (UAV) systems is traditionally managed by optimal control loops tuned to minimize errors in performance. While robust, these loops perform sub-optimally in dynamic and unpredictable environments which inspire new interest in sophisticated solution and approaches such as reinforcement learning (RL) approaches which should...
Advances in machine learning and artificial intelligence (AI) are enabling computers and robotics to take on an increasing number of work-related tasks that previously were the sole domain of humans. This trend raises questions: Which jobs will be most susceptible to replacement by automation? How many workers risk being replaced?...
This study explored the mentoring experiences of doctoral students in science, technology, engineering, and mathematics (STEM) doctoral degree programs at Northwestern University. Research suggests that mentoring relationships support student success in STEM disciplines, and further, that lack of mentorship may be a barrier for female students. A mixed-methods approach employing...
The concrete currently used in the slip-form paving process is a low slump concrete that requires both internal and external vibration in order to achieve satisfactory compaction. The use of vibrator fingers for the internal vibration often leads to trails on the surface of the pavement and to segregation around...
Performance monitoring of deep excavations typically includes slope inclinometers, optical surveying of soil deformation, tiltmeters and strain gages. Current monitoring data collection and processing requires time consuming site visits and manual data reduction by project engineers. Development of robotic and remote access geotechnical instrumentation conceptually allows processed data to be...
Experimental Time Domain Reflectometry (TDR) data obtained from the field are compared with numerical simulations using a finite-difference solution of the transmission line equations. The model simulates transmission of a voltage pulse along a lossy coaxial cable where deformities on the cable, such as crimps and shears, are represented by...
This thesis combines field and laboratory measurements with three dimensional (3D) finite element analysis (FEM) to demonstrate the use of Time Domain Reflectometry (TDR) cable-grout composites to measure localized shearing in soft soil. Past field installations of TDR cable-grout composites in rock have lead to its widespread use in the...
Miniaturized, wireless instrumentation is now a reality and this thesis describes development of such a system to monitor crack response. Comparison of environmental (long-term) and blast-induced (dynamic) crack width changes in residential structures has lead to a new approach to monitoring and controlling construction vibrations. In wireless systems transducer power...
Public concern over construction vibration-induced cracking has led to the development of a radically new approach to vibration, an autonomous crack comparometer (ACC). This thesis chronicles the first step of developing equipment and software necessary for this system. The new system will automatically compare longterm weather induced micrometer changes in...