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The human hand has so many degrees of freedom that it may seem impossible to control. A potential solution to this problem is “synergy control” which combines dimensionality reduction with great flexibility. With applicability to a wide range of tasks, this has become a very popular concept. In this review,

The human hand has so many degrees of freedom that it may seem impossible to control. A potential solution to this problem is “synergy control” which combines dimensionality reduction with great flexibility. With applicability to a wide range of tasks, this has become a very popular concept. In this review, we describe the evolution of the modern concept using studies of kinematic and force synergies in human hand control, neurophysiology of cortical and spinal neurons, and electromyographic (EMG) activity of hand muscles. We go beyond the often purely descriptive usage of synergy by reviewing the organization of the underlying neuronal circuitry in order to propose mechanistic explanations for various observed synergy phenomena. Finally, we propose a theoretical framework to reconcile important and still debated concepts such as the definitions of “fixed” vs. “flexible” synergies and mechanisms underlying the combination of synergies for hand control.

ContributorsSantello, Marco (Author) / Baud-Bovy, Gabriel (Author) / Jorntell, Henrik (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2013-04-08
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Nanomaterials enabled technologies have been seamlessly integrated into applications such as aviation and space, chemical industry, optics, solar hydrogen, fuel cell, batteries, sensors, power generation, aeronautic industry, building/construction industry, automotive engineering, consumer electronics, thermoelectric devices, pharmaceuticals, and cosmetic industry. Clean energy and environmental applications often demand the development of novel

Nanomaterials enabled technologies have been seamlessly integrated into applications such as aviation and space, chemical industry, optics, solar hydrogen, fuel cell, batteries, sensors, power generation, aeronautic industry, building/construction industry, automotive engineering, consumer electronics, thermoelectric devices, pharmaceuticals, and cosmetic industry. Clean energy and environmental applications often demand the development of novel nanomaterials that can provide shortest reaction pathways for the enhancement of reaction kinetics. Understanding the physicochemical, structural, microstructural, surface, and interface properties of nanomaterials is vital for achieving the required efficiency, cycle life, and sustainability in various technological applications. Nanomaterials with specific size and shape such as nanotubes, nanofibers, nanowires, nanocones, nanocomposites, nanorods, nanoislands, nanoparticles, nanospheres, and nanoshells to provide unique properties can be synthesized by tuning the process conditions.

ContributorsSrinivasan, Sesha (Author) / Kannan, Arunachala Mada (Author) / Kothurkar, Nikhil (Author) / Khalil, Yehia (Author) / Kuravi, Sarada (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2015-11-23
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Description

Urban water systems face sustainability and resiliency challenges including water leaks, over-use, quality issues, and response to drought and natural disasters. Information and communications technology (ICT) could help address these challenges through the development of smart water grids that network and automate monitoring and control devices. While progress is being

Urban water systems face sustainability and resiliency challenges including water leaks, over-use, quality issues, and response to drought and natural disasters. Information and communications technology (ICT) could help address these challenges through the development of smart water grids that network and automate monitoring and control devices. While progress is being made on technology elements, as a system, the smart water grid has received scant attention. This article aims to raise awareness of the systems-level idea of smart water grids by reviewing the technology elements and their integration into smart water systems, discussing potential sustainability and resiliency benefits, and challenges relating to the adoption of smart water grids. Water losses and inefficient use stand out as promising areas for applications of smart water grids. Potential barriers to the adoption of smart water grids include lack of funding for research and development, economic disincentives as well as institutional and political structures that favor the current system. It is our hope that future work can clarify the benefits of smart water grids and address challenges to their further development.

ContributorsMutchek, Michele (Author) / Williams, Eric (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2014-03-21
Description

Pay-for-performance (PFP) is a relatively new approach to agricultural conservation that attaches an incentive payment to quantified reductions in nutrient runoff from a participating farm. Similar to a payment for ecosystem services approach, PFP lends itself to providing incentives for the most beneficial practices at the field level. To date,

Pay-for-performance (PFP) is a relatively new approach to agricultural conservation that attaches an incentive payment to quantified reductions in nutrient runoff from a participating farm. Similar to a payment for ecosystem services approach, PFP lends itself to providing incentives for the most beneficial practices at the field level. To date, PFP conservation in the U.S. has only been applied in small pilot programs. Because monitoring conservation performance for each field enrolled in a program would be cost-prohibitive, field-level modeling can provide cost-effective estimates of anticipated improvements in nutrient runoff. We developed a PFP system that uses a unique application of one of the leading agricultural models, the USDA’s Soil and Water Assessment Tool, to evaluate the nutrient load reductions of potential farm practice changes based on field-level agronomic and management data. The initial phase of the project focused on simulating individual fields in the River Raisin watershed in southeastern Michigan. Here we present development of the modeling approach and results from the pilot year, 2015-2016. These results stress that (1) there is variability in practice effectiveness both within and between farms, and thus there is not one “best practice” for all farms, (2) conservation decisions are made most effectively at the scale of the farm field rather than the sub-watershed or watershed level, and (3) detailed, field-level management information is needed to accurately model and manage on-farm nutrient loadings.

Supplemental information mentioned in the article is attached as a separate document.

ContributorsMuenich, Rebecca (Author) / Kalcic, M. M. (Author) / Winsten, J. (Author) / Fisher, K. (Author) / Day, M. (Author) / O'Neil, G. (Author) / Wang, Y.-C. (Author) / Scavia, D. (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2017
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Description

We numerically demonstrate a switchable metamaterial absorber/emitter by thermally turning on or off the excitation of magnetic resonance upon the phase transition of vanadium dioxide (VO2). Perfect absorption peak exists around the wavelength of 5 lm when the excitation of magnetic resonance is supported with the insulating VO2 spacer layer.

We numerically demonstrate a switchable metamaterial absorber/emitter by thermally turning on or off the excitation of magnetic resonance upon the phase transition of vanadium dioxide (VO2). Perfect absorption peak exists around the wavelength of 5 lm when the excitation of magnetic resonance is supported with the insulating VO2 spacer layer. The wavelength-selective absorption is switched off when the magnetic resonance is disabled with metallic VO2 that shorts the top and bottom metallic structures. The resonance wavelength can be tuned with different geometry, and the switchable metamaterial exhibits diffuse behaviors at oblique angles. The results would facilitate the design of switchable metamaterials for active control in energy and sensing applications.

ContributorsWang, Hao (Author) / Wang, Yue (Author) / Wang, Liping (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2014-08-19
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Description

Humans are able to intuitively exploit the shape of an object and environmental constraints to achieve stable grasps and perform dexterous manipulations. In doing that, a vast range of kinematic strategies can be observed. However, in this work we formulate the hypothesis that such ability can be described in terms

Humans are able to intuitively exploit the shape of an object and environmental constraints to achieve stable grasps and perform dexterous manipulations. In doing that, a vast range of kinematic strategies can be observed. However, in this work we formulate the hypothesis that such ability can be described in terms of a synergistic behavior in the generation of hand postures, i.e., using a reduced set of commonly used kinematic patterns. This is in analogy with previous studies showing the presence of such behavior in different tasks, such as grasping. We investigated this hypothesis in experiments performed by six subjects, who were asked to grasp objects from a flat surface. We quantitatively characterized hand posture behavior from a kinematic perspective, i.e., the hand joint angles, in both pre-shaping and during the interaction with the environment. To determine the role of tactile feedback, we repeated the same experiments but with subjects wearing a rigid shell on the fingertips to reduce cutaneous afferent inputs. Results show the persistence of at least two postural synergies in all the considered experimental conditions and phases. Tactile impairment does not alter significantly the first two synergies, and contact with the environment generates a change only for higher order Principal Components. A good match also arises between the first synergy found in our analysis and the first synergy of grasping as quantified by previous work. The present study is motivated by the interest of learning from the human example, extracting lessons that can be applied in robot design and control. Thus, we conclude with a discussion on implications for robotics of our findings.

ContributorsDella Santina, Cosimo (Author) / Bianchi, Matteo (Author) / Averta, Giuseppe (Author) / Ciotti, Simone (Author) / Arapi, Visar (Author) / Fani, Simone (Author) / Battaglia, Edoardo (Author) / Giuseppe Catalano, Manuel (Author) / Santello, Marco (Author) / Bicchi, Antonio (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2017-08-29
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Description

In the two decades after 1990, the rates of child and maternal mortality dropped by over 40% and 47%, respectively. Despite these improvements, which are in part due to increased access to medical technologies, profound health disparities exist. In 2015, a child born in a developing region is nearly eight

In the two decades after 1990, the rates of child and maternal mortality dropped by over 40% and 47%, respectively. Despite these improvements, which are in part due to increased access to medical technologies, profound health disparities exist. In 2015, a child born in a developing region is nearly eight times as likely to die before the age of 5 than one born in a developed region and developing regions accounted for nearly 99% of the maternal deaths. Recent developments in nanotechnology, however, have great potential to ameliorate these and other health disparities by providing new cost-effective solutions for diagnosis or treatment of a variety of medical conditions. Affordability is only one of the several challenges that will need to be met to translate new ideas into a medical product that addresses a global health need. This article aims to describe some of the other challenges that will be faced by nanotechnologists who seek to make an impact in low-resource settings across the globe.

ContributorsAbbas, James (Author) / Smith, Barbara (Author) / Poluta, Mladen (Author) / Velazquez-Berumen, Adriana (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2017-03-29
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Description

Chromatin proteins have expanded the mammalian synthetic biology toolbox by enabling control of active and silenced states at endogenous genes. Others have reported synthetic proteins that bind DNA and regulate genes by altering chromatin marks, such as histone modifications. Previously, we reported the first synthetic transcriptional activator, the “Polycomb-based transcription

Chromatin proteins have expanded the mammalian synthetic biology toolbox by enabling control of active and silenced states at endogenous genes. Others have reported synthetic proteins that bind DNA and regulate genes by altering chromatin marks, such as histone modifications. Previously, we reported the first synthetic transcriptional activator, the “Polycomb-based transcription factor” (PcTF) that reads histone modifications through a protein–protein interaction between the polycomb chromodomain motif and trimethylated lysine 27 of histone H3 (H3K27me3). Here, we describe the genome-wide behavior of the polycomb-based transcription factor fusion protein. Transcriptome and chromatin profiling revealed several polycomb-based transcription factor-sensitive promoter regions marked by distal H3K27me3 and proximal fusion protein binding. These results illuminate a mechanism in which polycomb-based transcription factor interactions bridge epigenomic marks with the transcription initiation complex at target genes. In three cancer-derived human cell lines tested here, some target genes encode developmental regulators and tumor suppressors. Thus, the polycomb-based transcription factor represents a powerful new fusion protein-based method for cancer research and treatment where silencing marks are translated into direct gene activation.

ContributorsNyer, David (Author) / Daer, Rene (Author) / Vargas, Daniel (Author) / Hom, Caroline (Author) / Haynes, Karmella (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2017-01-09
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Description

Evolutionary games model a common type of interactions in a variety of complex, networked, natural systems and social systems. Given such a system, uncovering the interacting structure of the underlying network is key to understanding its collective dynamics. Based on compressive sensing, we develop an efficient approach to reconstructing complex

Evolutionary games model a common type of interactions in a variety of complex, networked, natural systems and social systems. Given such a system, uncovering the interacting structure of the underlying network is key to understanding its collective dynamics. Based on compressive sensing, we develop an efficient approach to reconstructing complex networks under game-based interactions from small amounts of data. The method is validated by using a variety of model networks and by conducting an actual experiment to reconstruct a social network. While most existing methods in this area assume oscillator networks that generate continuous-time data, our work successfully demonstrates that the extremely challenging problem of reverse engineering of complex networks can also be addressed even when the underlying dynamical processes are governed by realistic, evolutionary-game type of interactions in discrete time.

ContributorsWang, Wen-Xu (Author) / Lai, Ying-Cheng (Author) / Grebogi, Celso (Author) / Ye, Jieping (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2011-12-21
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Description

Various biologically inspired flow field designs of the gas distributor (interconnector) have been designed and simulated. Their performance using Nafion-212 with humidified H2 and Air at 80 °C with the ANSYS Fluent Fuel Cell module software was evaluated. Novel interdigitated designs were optimized by obeying biologically inspired branching rules. These

Various biologically inspired flow field designs of the gas distributor (interconnector) have been designed and simulated. Their performance using Nafion-212 with humidified H2 and Air at 80 °C with the ANSYS Fluent Fuel Cell module software was evaluated. Novel interdigitated designs were optimized by obeying biologically inspired branching rules. These rules allow for more mathematically formal descriptions of flow field designs, enabling relatively simple optimization. The channel to land ratio was kept equivalent between designs with typical values between 0.8 and 1.0. The pressure drop and the current density distribution were monitored for each design on both anode and cathode sides. The most promising designs are expected to exhibit lower pressure drop however, low pressure drop can also be an indication of potential water flooding at higher operating current density. A biologically inspired interdigitated design with 9 inlet channels exhibited reduced pressure drop and improved current density distribution compared to all other interdigitated designs evaluated in this study. The simulated fuel cell performance data at ambient pressure with humidified H2 and air compares well with the experimental data using a single serpentine flow field design.

ContributorsArvay, Adam (Author) / French, Jason (Author) / Wang, Jui-Chieh (Author) / Peng, Xihong (Author) / Kannan, Arunachala Mada (Author) / Ira A. Fulton Schools of Engineering (Contributor)
Created2015