5 research outputs found
Geotechnical test embankment on soft marine clay in Newington-Dover, New Hampshire
During the fall of 2012, the New Hampshire Department of Transportation built a test embankment for the new alignment segment of the proposed Exit 6 Southbound On-Ramp site off Route 4 in Newington-Dover, New Hampshire. The purpose of the test embankment is to determine effective and efficient treatment for the long-term ground settlement of the local soft marine clay native to the site. In addition to the test embankment, prefabricated vertical drains were installed to allow pore water from the soil to seep out and accelerate time-rate consolidation. Various in situ field testing methods were performed including: piezocone penetration, flat plate dilatometer and field shear vane. Additionally, consolidation testing was performed in the laboratory with undisturbed samples of the clay. Settlement calculations were performed to compare with field values. This research will benefit construction of the site, in addition to many other upcoming sites of construction in the local area
Development of FEM laboratory modules for an introductory undergraduate Geotechnical Engineering course
While geotechnical and structural engineers routinely rely heavily on finite element (FEM) modeling for analysis and design, exposure to numerical modeling and to software used in industry is generally limited in most civil engineering undergraduate curricula. This document summarizes the experience of introducing an industry FEM software - Midas GTS NX – into the Geotechnical Engineering I course at Purdue University in the Spring 2020 semester, through two laboratory modules built around key topics covered in the course: 2D groundwater flow and stress analysis. In addition to providing exposure to tools used in practice, the modules were designed to consolidate the comprehension of fundamental concepts, and enhance students’ learning experience by facilitating rapid iterative exploration of different technical scenarios in the context of practical applications of geotechnical engineering
Investigation of Design Alternatives for the Subbase of Concrete Pavements
In all pavement structures, one or more support layers separate the pavement from the subgrade. In addition to offering structural support, these layers have several important functions, which include: providing a stable and uniform construction platform, facilitating drainage, mitigating pumping of the subgrade fines, and protecting the pavement from the effects of frost heave. Their performance is critical in achieving the desired pavement smoothness, and in extending the service life of the structure. A range of designs, making use of unbound or stabilized aggregates and in some cases geosynthetics, are employed by different agencies to fulfill these functions.
This project was motivated by constructability and long term performance concerns with the existing base/subbase design employed by INDOT for concrete pavements, as well as the desire to identify state of the art design solutions that could be applicable to both concrete and asphalt pavements. The primary objectives of the study were to: critically reexamine INDOT’s existing design; perform a preliminary evaluation (based on aggregate compaction, hydraulic conductivity, strength and compatibility properties) of select unbound design options identified in collaboration with the Study Advisory Committee (SAC); explore the potential use of geotextiles as separator; and develop recommendations for base/subbase aggregate laboratory testing and evaluation
Repurposing an EMG Biofeedback Device for Gait Rehabilitation: Development, Validity and Reliability
Gait impairment often limits physical activity and negatively impacts quality of life. EMG-Biofeedback (EMG-BFB), one of the more effective interventions for improving gait impairment, has been limited to laboratory use due to system costs and technical requirements, and has therefore not been tested on a larger scale. In our research, we aimed to develop and validate a cost-effective, commercially available EMG-BFB device for home- and community-based use. We began by repurposing mTrigger® (mTrigger LLC, Newark, DE, USA), a cost-effective, portable EMG-BFB device, for gait application. This included developing features in the cellphone app such as step feedback, success rate, muscle activity calibration, and cloud integration. Next, we tested the validity and reliability of the mTrigger device in healthy adults by comparing it to a laboratory-grade EMG system. While wearing both devices, 32 adults walked overground and on a treadmill at four speeds (0.3, 0.6, 0.9, and 1.2 m/s). Statistical analysis revealed good to excellent test–retest reliability (r > 0.89) and good to excellent agreement in the detection of steps (ICC > 0.85) at all speeds between two systems for treadmill walking. Our results indicated that mTrigger compared favorably to a laboratory-grade EMG system in the ability to assess muscular activity and to provide biofeedback during walking in healthy adults
Effect of a Novel Multicomponent Intervention to Improve Patient Access to Kidney Transplant and Living Kidney Donation: The EnAKT LKD Cluster Randomized Clinical Trial
Importance: Patients with advanced chronic kidney disease (CKD) have the best chance for a longer and healthier life if they receive a kidney transplant. However, many barriers prevent patients from receiving a transplant.
Objectives: To evaluate the effect of a multicomponent intervention designed to target several barriers that prevent eligible patients from completing key steps toward receiving a kidney transplant.
Design, setting, and participants: This pragmatic, 2-arm, parallel-group, open-label, registry-based, superiority, cluster randomized clinical trial included all 26 CKD programs in Ontario, Canada, from November 1, 2017, to December 31, 2021. These programs provide care for patients with advanced CKD (patients approaching the need for dialysis or receiving maintenance dialysis).
Interventions: Using stratified, covariate-constrained randomization, allocation of the CKD programs at a 1:1 ratio was used to compare the multicomponent intervention vs usual care for 4.2 years. The intervention had 4 main components, (1) administrative support to establish local quality improvement teams; (2) transplant educational resources; (3) an initiative for transplant recipients and living donors to share stories and experiences; and (4) program-level performance reports and oversight by administrative leaders.
Main outcomes and measures: The primary outcome was the rate of steps completed toward receiving a kidney transplant. Each patient could complete up to 4 steps: step 1, referred to a transplant center for evaluation; step 2, had a potential living donor contact a transplant center for evaluation; step 3, added to the deceased donor waitlist; and step 4, received a transplant from a living or deceased donor.
Results: The 26 CKD programs (13 intervention, 13 usual care) during the trial period included 20 375 potentially transplant-eligible patients with advanced CKD (intervention group [n = 9780 patients], usual-care group [n = 10 595 patients]). Despite evidence of intervention uptake, the step completion rate did not significantly differ between the intervention vs usual-care groups: 5334 vs 5638 steps; 24.8 vs 24.1 steps per 100 patient-years; adjusted hazard ratio, 1.00 (95% CI, 0.87-1.15).
Conclusions and relevance: This novel multicomponent intervention did not significantly increase the rate of completed steps toward receiving a kidney transplant. Improving access to transplantation remains a global priority that requires substantial effort