13 results on '"U. Balachandran"'
Search Results
2. Preparation and electrical conductivity of graphitic carbon-infused copper alloys
- Author
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Beihai Ma, Tae H. Lee, U. Balachandran, S. E. Dorris, and Adam J. Rondinone
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Materials science ,Scanning electron microscope ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper ,0104 chemical sciences ,International Annealed Copper Standard ,chemistry ,Electrical resistivity and conductivity ,General Materials Science ,0210 nano-technology ,Porosity ,Carbon ,Electrical conductor ,Helium - Abstract
By electron-beam (e-beam) melting, we prepared 0.4 wt% carbon-infused copper (CuCv4), and a copper control without carbon addition (CuCvO). Scanning electron microscopy and helium ion microscopy (HIM) were performed on the as-solidified surface, fracture surface, and ion-polished surface of the CuCv4 sample. The results revealed that graphitic carbon flakes cover the as-solidified surface, and carbon nanoparticles and clusters exist in the fracture and ion-polished surfaces. HIM on the ion-polished surface revealed a unique ripple-shaped feature, which is possibly associated with the infusion of carbon nanoribbons in the copper matrix. The bulk densities were measured to be 8.86 and 8.53 g/cm3, which correspond to relative densities of 98.9% and 96.4% for the CuCvO and CuCv4 samples, respectively. In addition, apparent electrical conductivities were measured to be 56.9 and 57.5 MS/m, respectively, for the e-beam melted CuCvO and CuCv4 samples. These values correspond to true electrical conductivities of 100.5% IACS (International Annealed Copper Standard) and 107.4% IACS after correction for the porosity. Our results reveal remarkable promise of using covetic copper for the next generation conductors in energy applications from microelectronic devices to high-power transmission cables.
- Published
- 2019
3. Physical and mechanical properties of a novel hydrogen transport membrane
- Author
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Lily Yongjun Zhang, U. Balachandran, Nagendra Nag, and Sukumar Bandopadhyay
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Materials science ,Mechanical Engineering ,Modulus ,02 engineering and technology ,Cermet ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Stress (mechanics) ,Shear modulus ,Flexural strength ,Mechanics of Materials ,visual_art ,Vickers hardness test ,visual_art.visual_art_medium ,General Materials Science ,Cubic zirconia ,Ceramic ,Composite material ,0210 nano-technology - Abstract
A novel cermet (ceramic/metal composite) hydrogen transport membrane (HTM) was characterized for its physical and mechanical properties at both room temperature and at elevated temperature of 850 °C. The density of the HTM cermet was measured as 8.9 g/cm3 at ambient temperature with dynamic Young’s modulus of 145.5 GPa and the dynamic shear modulus (G-value) of 54.29 GPa, whereas the Poisson’s ratio (υ) is calculated to be 0.34. Vickers hardness numbers for the as-received HTM cermet are constant and in the range of 2.0–2.2 GPa, with the change of loading force from 100 to 1000 g. The flexural strength (σ fs) of the HTM cermet is about 356 MPa at room temperature and decreases to 284 MPa at the elevated temperature of 850 °C in both air and nitrogen. A difference in testing atmosphere (air or N2) had insignificant effect on the load–displacement curves during the flexural strength test at the elevated temperature of 850 °C. From the load–displacement curves, HTM cermet behaves much more like elastic material at room temperature; with the temperature increased to 850 °C, its behaviour is much more like a metallic material with fractures preceded by plastic deformation. The initial yielding strength of HTM could be mainly controlled by the yield strength of the soft Pd metal material, and the zirconia fractures before yielding in Pd at room temperature, whereas at 850 °C, the yield stress of the Pd drops dramatically and allows it to work and harden in the constraint of a rigid ceramic. The final failure load is mainly dictated by ceramic fracture, while the initial yielding stress is determined on the yield strength of the soft Pd metal at both room temperature and the elevated temperature of 850 °C.
- Published
- 2016
4. Nanocarbon-Infused Metals: A New Class of Covetic Materials for Energy Applications
- Author
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U. Balachandran, David Forrest, Rachel E. Koritala, Beihai Ma, and S. E. Dorris
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Materials science ,chemistry ,Energy transfer ,chemistry.chemical_element ,Grain boundary ,Lorenz number ,Carbon ,Engineering physics ,Energy (signal processing) - Published
- 2018
5. Development of Capacitors for Power Electronics in Hybrid Vehicles
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U. Balachandran
- Subjects
Capacitor ,Engineering ,Fabrication ,business.industry ,law ,Power electronics ,Fuel efficiency ,Electrical engineering ,business ,Electric drive ,Manufacturing cost ,law.invention - Abstract
The purpose of this CRADA is to develop a fabrication process to reduce the manufacturing cost for a very compact, high temperature, film-on-foil high energy-density PLZT (Pb-La-Zr- Ti-O) capacitor. Motivation for this CRADA is derived from the DOE’s Office of Vehicle Technologies (OVT) program, which seeks to advance technologies to improve vehicle fuel efficiency in the mid-term and facilitate the transition to electric drive vehicles over the longterm. The objective of Argonne’s work is to develop and characterize high-performance capacitors on base-metal foils. The PLZT film-on-foil prepared using a spin-coating technique
- Published
- 2016
6. Structural characterization of nanophase-carbon in covetic materials
- Author
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Beihai Ma, U. Balachandran, Jianguo Wen, Miller, Dean J., Winarski, Robert P, Segre, Carlo U, and Joy, David C
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- 2015
- Full Text
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7. Investigation of carbon nanostructure in copper covetics by x-ray nanotomography
- Author
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Winarski, Robert P, Beihai Ma, J. Wen, D. Miller, Forrest, David, U. Balachandran, and Segre, Carlo
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- 2015
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8. Thermal Shock Induced Phases Transformation and Microstructural Changes in a Novel Hydrogen Transport Membrane
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U. Balachandran, Yongjun Zhang Lily, Sukumar Bandopadhyay, and Nagendra Nag
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Thermal shock ,Materials science ,Scanning electron microscope ,Energy-dispersive X-ray spectroscopy ,Fractography ,Electron microprobe ,Temperature cycling ,Cermet ,Composite material ,Yttria-stabilized zirconia - Abstract
Bulk samples of a novel cermet (ceramic/metal composite) hydrogen transport membrane (HTM) were subjected to thermal cycling in the temperature range between 25-850°C to study phase transformations and microstructural changes under thermal shock. Scanning electron microscopy (SEM) and electron probe micro analyzer (EPMA) with energy dispersive spectroscopy (EDS) were used to characterize the microstructural and chemical changes in the membrane upon thermal cycling. SEM & EPMA analyses indicated that the temperature gradient during thermal cycling produced more micro-cracks inside the HTM disc, whereas, the chemical reaction between Pd and oxygen to form PdO disturbed the continuity of the metal palladium (Pd) - Yttria Stabilized Zirconia (YSZ) dual phases interconnection system from surface down. The agglomerates of un-crystallized YSZ grains found to be the inherent in the cracks of the as-received HTM. A combination of trans-granular and inter-granular crack propagation results around the YSZ grains and the new precipitates. Based on the electron fractography analyses by both SEM and EPMA, the micro voids coalescence develops ahead of the crack tips in the cross-section of the HTM after 500 thermal cycles.
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- 2015
9. What's Important: Equitable Orthopaedic Care for Patients with Disabilities.
- Author
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Balachandran U and Stern BZ
- Abstract
Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJS/I143).
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- 2024
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10. Associations Between Prehabilitation and Postoperative Healthcare Utilization for Total Hip or Total Knee Arthroplasty in Medicare Beneficiaries.
- Author
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Sabo G, Stern BZ, Balachandran U, Agranoff R, Hayden BL, Poeran J, and Moucha CS
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Background: Prehabilitation has potential to improve outcomes in value-based care models. We examined the associations between receipt of prehabilitation (physical therapy [PT] services within 30 days preoperatively) and postoperative healthcare utilization in a national cohort of fee-for-service Medicare beneficiaries., Methods: This retrospective cohort study used the 5% fee-for-service claims from the Medicare Limited Data Set to identify unilateral elective inpatient total hip arthroplasty (THA) procedures (n = 25,509) and total knee arthroplasty (TKA) procedures (n = 40,091) from January 1, 2016 to September 30, 2021. Associations between prehabilitation and postoperative healthcare utilization were analyzed in mixed-effects generalized linear models adjusting for patient-level and hospital-level factors. We report adjusted odds ratios (OR) or % differences., Results: Prehabilitation (13.1% THA, 13.1% TKA) was not significantly associated with institutional post-acute care discharge, 30-day emergency department visits, or 90-day readmissions. For TKA, prehabilitation was significantly associated with decreased odds of an extended hospital length of stay (OR = 0.86, P = 0.02) and reduced length of stay in an institutional post-acute care facility (-5.71%, P = 0.004). In both THA and TKA, prehabilitation was associated with decreased use of 90-day home health physical and/or occupational therapy (THA: OR = 0.82, P = 0.001; TKA: OR = 0.67, P < 0.001). In contrast, prehabilitation in both cohorts was associated with increased odds of receiving any 90-day outpatient PT (THA: OR = 2.08, P < 0.001; TKA: OR = 2.48, P < 0.001) and an increased number of 90-day outpatient PT visits (THA: +4.04%, P = 0.01; TKA: +5.21%, P < 0.001)., Conclusion: Prehabilitation was associated with some decreases in postoperative healthcare utilization, particularly for TKA. Associations of preoperative physical therapy with increased postoperative outpatient physical therapy may reflect variation in referral patterns or patient access. These results highlight the importance of continued research into the impact of prehabilitation on healthcare utilization, patient outcomes, and episode costs. Additionally, further research should identify which patients would benefit the most from prehabilitation to increase the value of care., (Copyright © 2024. Published by Elsevier Inc.)
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- 2024
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11. Evaluating inhaler education interventions for hospitalized children with asthma: A randomized controlled trial.
- Author
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Volerman A, Balachandran U, Zhu M, Akel M, Hull A, Siros M, Luna V, Xu I, and Press VG
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- Child, Humans, Adolescent, Child, Preschool, Administration, Inhalation, Nebulizers and Vaporizers, Educational Status, Child, Hospitalized, Asthma drug therapy
- Abstract
Background: Most children with asthma have poor inhaler technique, with detrimental morbidity effects. Guidelines recommend clinicians provide inhaler education at every opportunity, yet resources are limited. A low-cost, technology-based intervention-Virtual Teach-to-Goal (V-TTG)-was developed to deliver tailored inhaler technique education with high fidelity., Objective: To evaluate whether V-TTG leads to less inhaler misuse among children with asthma who are hospitalized vs brief intervention (BI, reading steps aloud)., Methods: A single-center randomized controlled trial of V-TTG vs BI was conducted with 5-to-10-year-old children with asthma hospitalized between January 2019 and February 2020. Inhaler technique was assessed pre- and post-education using 12-step validated checklists (misuse: < 10 steps correct)., Results: Among 70 children enrolled, mean age was 7.8 years (SD = 1.6). Most (86%) were Black. Most had an emergency department visit (94%) or hospitalization (90%) in the previous year. At baseline, nearly all children misused inhalers (96%). The proportion of children with inhaler misuse decreased significantly in V-TTG (100%→74%, P = .002) and BI (92%→69%, P = .04) groups, with no difference between groups at both time points (P = .2 and .9). On average, children performed 1.5 more steps correctly (SD = 2.0), with greater improvement with V-TTG (mean [SD] = 1.7 [1.6]) vs BI (mean [SD] = 1.4 [2.3]), though not significant (P = .6). Concerning pre and post technique, older children were significantly more likely than younger children to show more correct steps (mean change = 1.9 vs 1.1, P = .002)., Conclusion: A technology-based intervention for tailored inhaler education led to improved technique among children, similarly to reading steps aloud. Older children saw greater benefits. Future studies should evaluate the V-TTG intervention across diverse populations and disease severities to identify the greatest impact., Clinical Trial Registration: NCT04373499., (Copyright © 2023 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)
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- 2023
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12. Reply: Utility of a Mask with a Spacer to Deliver the Contents of a Metered Dose Inhaler.
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Volerman A, Balachandran U, Siros M, Akel M, and Press VG
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- Administration, Inhalation, Child, Humans, Metered Dose Inhalers, Nebulizers and Vaporizers, Asthma drug therapy, Inhalation Spacers
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- 2021
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13. Mask Use with Spacers/Valved Holding Chambers and Metered Dose Inhalers among Children with Asthma.
- Author
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Volerman A, Balachandran U, Siros M, Akel M, and Press VG
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- Child, Equipment Design, Humans, Nebulizers and Vaporizers, Asthma drug therapy, Inhalation Spacers, Metered Dose Inhalers
- Abstract
Inhaler misuse is highly prevalent and associated with high morbidity and costs. For metered dose inhalers, proper use can be supported with devices such as spacers/valved holding chambers (VHCs) and masks to effectively deliver inhaled medication to the lungs. However, guidelines are vague about which children with asthma should use spacers/VHCs with masks to deliver medication from metered dose inhalers as well as when they should transition to spacers/VHCs with mouthpieces. In this paper, we provide a focused review of the evidence for mask use, highlighting unclear and conflicting information in guidelines and studies. We synthesize the differences in recommendations and practice. Based on these findings, we call for future research to determine the appropriate age and necessary skills for transitioning children from using metered dose inhalers with spacers/VHCs and masks to using spacers/VHCs and mouthpieces. Guidelines about mask use should be standardized to help ensure optimal medical delivery for patients, provide consistent inhaler prescriptions and education across settings, and support team-based care to help lower pediatric asthma morbidity and costs.
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- 2021
- Full Text
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