Humans are unique in their ability to think abstractly (e.g. using language, learning relations). Previous work from our lab has shown that infants can learn simple abstract relations, like whether two objects are the “same” or “different”. In this study, we investigated flexibility in early learning. Our question was whether...
Aim to facilitate the production of the treatment by optimizing reproducibility and minimizing cost. Tasks: Find cost/time effective way to reach end product, Perfecting technique to increase yield, Adjusting known procedure when necessary, Molecule compliant with drug-like properties (Lipiphilic, Ingestible, Long half-life)
Research questions: Do students face pressure to choose certain racial identities in different social spheres on campus? What identities are selected in what situations? What struggles are faced by those of more than one race on Northwestern’s campus? What privileges are associated with being a multi-racial student at Northwestern University?...
Which areas of Chicago have greater concentrations of lead in their water and is that associated with environmental racism? Since Chicago is racially segregated, the marginalized areas such as the south side and west side are more likely to contain high levels of lead.
Neuroscience research has made many important contributions to the study of the brain and behavior. Perhaps because of these contributions the general public seems to be easily seduced by neuroscientific explanations. Meaning that when a scientific article is paired with a brain image, the information within the article is automatically...
The Center for Advanced Cement-Based Materials (ACBM) is a consortium of researchers from: Northwestern University, University of Illinois at Urbana-Champaign, Purdue University, The University of Michigan, and The National Institute of Standards and Technology. This ACBM update contains information on the article "A better Maturity Meter?" by Surendra P. Shah...
In this paper, the correlation of reflection loss measured by an ultrasonic shear wave reflection
method and the microstructure in cement-based material is investigated. Three cement pastes
(Portland cement type I) with different water-cement ratios (0.35, 0.50 and 0.60) cured at 25
°C were examined. The ultrasonic shear wave reflection...
The nondestructive, in-situ testing of early-age concrete properties is a crucial point for the progress of many construction projects in the building sector. The application of such techniques can establish e.g. the earliest possible form removal from concrete construction elements, thereby opening highways to traffic or releasing prestress from steel...
The setting and hardening process of concrete is considered to be the most critical time period during the life of a concrete structure. Previous research has been conducted on an ultrasonic wave reflection method that utilizes a steel plate embedded in the concrete to measure the reflection loss of shear...
The gradual evolution of the material properties of a cement-based material, i.e. the stiffness of cement paste, is the result of the continuous change of the microstructure with the progress of the hydration process. Based on an existing micromechanical model for the simulation of the shear and elastic modulus of...
The setting and hardening process of concrete can be considered as the most critical time period during the life of a concrete structure. To assure high quality and avoid problems in performance throughout the life of the material, it is essential to have reliable information about the early age properties...
This presentation contains information on the keynote paper "Health Monitoring of Early Age Concrete". The presentation was delivered by Surendra P. Shah at CONSEC'04 in Seoul, Korea on June 30, 2004.
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...
The paper deals with the behavior of fluid cement pastes, formulated from Self Consolidating Concretes (SCCs), and the experimental correlation of fundamental rheological properties, such as the yield stress and the viscosity, with measurements from field tests, such as the mini-cone slump flow test. As a matter of fact, several...
This presentation contains information on the project "Aligning Data to Support Transportation Decisions, Emerging Challenges & Opportunities for the Data World". The presentation was delivered by Joseph L. Schofer at Transportation Research Board – AASHTO Peer Exchange meeting on May 15-16, 2008.
This presentation contains information about the project "The future of transportation... and how we'll pay for it" by Joseph L. Schofer, Department f Civil & Environmental Engineering. The presentation was delivered at the 40th Anniversary Seminar Day at Northwestern University on April 18, 2009.
This presentation provides information on the project "Safety Concrete - a Material Designed to Fail" by Jeffrey J. Thomas, Julie Gevrenov, Hamlin Jennings, and Edward O'Neil. The presentation was delivered at the 106th Annual Meeting & Exposition of The American Ceramic Society, Indianapolis, Indiana in 2004.
The objective of this program is to measure the changes in the properties of the C-S-H gel phase in cement paste as a function of the Ca/Si ratio. The motivation is to better understand the hydration products that form in blended cements with lower Ca/Si ratios than portland cement. The...
A study is conducted to determine the effects on the early hydration kinetics and
compressive strength by seeding of Portland cement and alkali-activated blast furnace
slag with a pure form of calcium silicate hydrate (C-S-H). The effects of C-S-H seeding
during the early nucleation and growth period of each type...
This presentation provides information on the progress report of the project "Empirical Study of Life-Cycle Cost Analysis for Bridges" by Ahmad Hadavi, 2003.
Non-destructive evaluation (NDE) techniques have been used for a number of years to provide quality control of construction procedures for drilled shafts and driven concrete piles. In particular sonic echo and impulse response methods have been used extensively to check lengths and continuity of newly-installed foundations. In recent years, the...
An empirical procedure for fitting a complementary error function (erfc) to settlement and lateral ground movement data in a direction parallel to an excavation support wall is proposed based on extensive optical survey data obtained around a 12.8 m excavation in Chicago. The maximum ground movement and the height and...
Several three-dimensional effects were observed in the performance monitoring data collected during excavation for the Ford Engineering Design Center (FEDC) in Evanston, Illinois. These responses are related to lateral deformations of the soil around the excavation walls, forces in the cross-lot and diagonal bracing that supported the temporary wall and...
This paper presents the results of 159 finite element simulations conducted to define the effects of excavation geometry, i.e., length, width and depth of excavation, wall system stiffness, and factor of safety against basal heave on the 3-dimensional ground movements caused by excavation through clays. The results of the analyses...
Successful use of monitoring data to update performance predictions of supported excavations depends equally on reasonable numerical simulations of performance, the type of monitoring data used as observations, and the inverse analysis techniques used to minimize the difference between predictions and observed performance. This paper summarizes each of these factors...
Two numerical procedures are described that quantitatively identify a set of constitutive parameters that best represents observed ground movement data associated with a deep excavations in urban environments. This inverse problem is solved by minimizing an objective (or error) function of the weighted least-squares type that contains the difference between...
This paper describes developments of integrated tools for predicting, monitoring, and controlling ground movements associated with excavations in urban areas. Successful use of monitoring data to update performance predictions of supported excavations depends equally on reasonable numerical simulations of performance, the type of monitoring data used as observations, and the...
This presentation provides information on the the project "Use Of High-Performance A710 Grade B Steel in Construction of Lake Villa, IL Bridge". The presentation was delivered by Morris E. Fine, Semyon Vaynman, and Nunzio Mario Biondolillo on June 14, 2006.
During the past several years an easily weldable, high strength (more than 75 ksi yield), high impact fracture toughness steel (NUCu steel) has been investigated at Northwestern University with bridge applications in mind. For good weldability without pre-heating and post-heating, the carbon content of the steel was kept low and...
Northwestern University developed copper-precipitation-hardened, high-performance weathering steel (NUCu 70W Steel) that is produced by hot rolling after casting and then air-cooling. Due to simple processing the steel is fabricated at lower cost than competing high-performance steels that require quench and tempering. NUCu 70W steel can be easily welded without pre-...
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...
This file contains power-point slides of Application to Crossbow’s Smart Dust Challenge Contest, title "Wireless Data Acquisition System" by Mat Kotowsky and Hasan Ozer. The presentation was delivered at University of California, Berkeley on February 11, 2005.
This paper describes qualification of devices to measure sub micro-meter changes in crack width, which is the basis of autonomous crack monitoring for control of blasting vibrations. Performance of LVDT, eddy current and potentiometer sensors to monitor long-term and transient displacements will be described. Potentiometers are attractive for wireless measurement,...
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...
Construction is omnipresent in modern-day America. It's the sound and vibration of a nation scrambling to keep up with its burgeoning population. In most states, allowable construction-induced ground motions range from 0.5 to 1.0 inches per second (in/sec) and under certain
conditions up to 2.0 in/sec.
However, ground motion as...