Effects of fabrication conditions on mechanical properties and microstructure of duplex β''-Al₂O₃ solid electrolyte

Canfield, N.L.,Kim, J.Y.,Bonnett, J.F.,Pearson, R.L.,Sprenkle, V.L.,Jung, K. Elsevier 2015 Materials science and engineering B. Advanced Func Vol.197 No.-

Na-beta batteries are an attractive technology as a large-scale electrical energy storage for grid applications. However, additional improvements in performance and cost are needed for wide market penetration. To improve cell performance by minimizing polarizations, reduction of electrolyte thickness was attempted using a duplex structure consisting of a thin dense electrolyte layer and a porous support layer. In this paper, the effects of sintering conditions, dense electrolyte thickness, and cell orientation on the flexural strength of duplex BASEs fabricated using a vapor phase approach were investigated. It is shown that sintering at temperatures between 1500 and 1550<SUP>o</SUP>C results in fine grained microstructures and the highest flexural strength after conversion. Increasing thickness of the dense electrolyte has a small impact on flexural strength, while the orientation of load such that the dense electrolyte is in tension instead of compression has major effects on strength for samples with a well-sintered dense electrolyte.

Closing the “CIM GAP” in the Process Industries

FRANK B. CANFIELD,PRATAP K. NAIR 제어로봇시스템학회 1991 제어로봇시스템학회 국내학술대회 논문집 Vol.1 No.2

Closing the " CIM GAP " in the Process Industries

Frank B. Canfield,Pratap K. Nair 대한전자공학회 1991 대한전자공학회 학술대회 Vol.1991 No.01

Advanced Na-NiCl₂ Battery Using Nickel-Coated Graphite with Core–Shell Microarchitecture

Chang, Hee-Jung,Canfield, Nathan L.,Jung, Keeyoung,Sprenkle, Vincent L.,Li, Guosheng American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.13

<P>Stationary electric energy storage devices (rechargeable batteries) have gained increasing prominence due to great market needs, such as smoothing the fluctuation of renewable energy resources and supporting the reliability of the electric grid. With regard to raw materials availability, sodium-based batteries are better positioned than lithium batteries due to the abundant resource of sodium in Earths crust. However, the sodium-nickel chloride (Na-NiCl2) battery, one of the most attractive stationary battery technologies, is hindered from further market penetration by its high material cost (Ni cost) and fast material degradation at its high operating temperature. Here, we demonstrate the design of a coreshell microarchitecture, nickel-coated graphite, with a graphite core to maintain electrochemically active surface area and structural integrity of the electron percolation pathway while using 40% less Ni than conventional Na-NiCl2 batteries. An initial energy density of 133 Wh/kg (at similar to C/4) and energy efficiency of 94% are achieved at an intermediate temperature of 190 degrees C.</P>

A duplex β″-Al₂O₃ solid electrolyte consisting of a thin dense layer and a porous substrate

Kim, Jin Y.,Canfield, Nathan L.,Bonnett, Jeff F.,Sprenkle, Vincent L.,Jung, Keeyoung,Hong, Inchul Elsevier 2015 Solid state ionics Vol.278 No.-

<P><B>Abstract</B></P> <P>To improve the performance of Na-beta batteries at intermediate temperatures (≤200°C) where much improved cyclability and reduced degradation can be achieved, there is a need to lower the resistance/polarization originated from β″-Al<SUB>2</SUB>O<SUB>3</SUB> solid electrolyte (BASE) while maintaining its good strength. In this paper, the concept of a duplex BASE consisting of a thin dense electrolyte and a porous support was proposed as a solution to achieve low area-specific resistance (ASR) with good mechanical strength supported by the porous substrate. The effects of various factors including porosity, composition, and homogeneity of ingredients on the flexural strength of duplex BASEs were examined. In summary, lower porosity, higher YSZ content in the structure, and attrition milling of raw powders resulted in improved strength. The ASR measurement exhibited that the resistance of duplex BASEs was mainly originated from a dense layer. Overall, the maximum strength of 260MPa and the ASR value of 0.31Ωcm<SUP>2</SUP> (at 350°C) was achieved from a duplex BASE consisting of a 50μm thick dense layer (Al<SUB>2</SUB>O<SUB>3</SUB>:YSZ=7:3 in volume) and a 500μm thick porous support (Al<SUB>2</SUB>O<SUB>3</SUB>:YSZ=4:6 in volume with 19% open porosity). The effects of various factors on the properties of duplex BASEs will be discussed in detail.</P> <P><B>Highlights</B></P> <P> <UL> <LI> As a method to lower the ASR, the concept of duplex BASEs is presented. </LI> <LI> A duplex BASEs consists of a thin dense β″-alumina layer and a mechanically strong porous support. </LI> <LI> Processing factors including conversion, porosity, composition, and homogeneity influence the strength of a duplex BASE. </LI> <LI> The minimum ASR value of 0.31Ωcm<SUP>2</SUP> was achieved at 350°C with decent strength of 260MPa. </LI> </UL> </P>

Prostate Cancer Mortality and Use of 5-Alpha Reductase Inhibitors

Cara A. Foldes,Run Wang,Steven E. Canfield 대한남성과학회 2020 The World Journal of Men's Health Vol.38 No.2

Prostate cancer prevention was a goal of intense research and expenditure in the nineties through the early two-thousands. The largest prevention trial ever planned was the Selenium and Vitamin E Prostate Cancer Prevention Trial (SELECT) which enrolled 35,533 men but closed early due to futility and concern for increased prostate cancer from vitamin E [1]. A slightly different story but similar fate occurred with the Prostate Cancer Prevention Trial, which randomized 18,882 men with no clinical evidence of prostate cancer to take the 5-alpha reductase inhibitor (5-ARI) finasteride vs. a placebo [2]. The trial showed a 24.8% overall relative risk reduction in prostate cancer incidence, yet widespread use of finasteride for prevention never occurred. The reason is that the trial also showed a small but significant increase in the incidence of higher grade prostate cancer in the treatment arm, which led to a US Food and Drug Administration black box warning on the medication. Ultimately, this risk was understood to be due to detection bias inherent in the use of finasteride, but the stigma remained [3]. Perhaps more importantly, the reduction in prostate cancer was only seen in low risk, clinically insignificant prostate cancer. A second 5-ARI trial with dutasteride, a more potent blocker, also reported similar results, for low risk prostate cancer prevention [4]. Due to the lack of benefit in clinically significant disease, and controversy surrounding potential harms, this class of medication was never adopted for prevention and remained a footnote in prostate cancer history. A new study from Sarkar et al [5] suggests the 5-ARI story in prostate cancer is not over yet, however. Finasteride and dutasteride are commonly used to improve bladder outlet obstructive urinary symptoms in men with benign prostatic hyperplasia. In addition to a reduction in the size of the prostate, one of the most prominent effects of these medications is an approximate 50% reduction in the serum prostate specific antigen (PSA) concentration [6]. The appropriate PSA based screening for prostate cancer practice in men on 5-ARIs is to therefore normalize the PSA by doubling it in these men, for appropriate population based comparisons [7]. There has been speculation that this normalization is seldom done in primary care practices that pursue PSA screening in general, which may lead to delays in detection and worse outcomes for some men. Sarkar and colleagues [5] performed a retrospective cohort comparison of men in the Veterans Affairs database who were diagnosed with prostate cancer from 2001 to 2015. The cohort consisted of 80,875 men, of whom 8,587 (10.6%) had been prescribed a 5-ARI at least 1 year prior to diagnosis. The study found that men taking 5-ARIs had significantly higher rates of prostate cancer-specific (39% greater) and overall (10% greater) mortality. Interestingly, there was no difference in non-cancer related mortality. Secondary outcomes were also worse across all measures in the 5-ARI group, showing a significant delay in time to diagnosis of cancer (3.6 vs. 1.2 years), higher adjusted PSA value (13.5 vs. 6.4 ng/mL), higher grade (25.2% vs. 17% Gleason 8–10), stage (4.7% vs. 2.9% T3–4), presence of lymph nodal (3.0% vs. 1.7%), and metastatic disease (6.7% vs. 2.9%) at diagnosis. In the absence of randomized controlled trials, these findings would raise greater concerns over the effects of 5-ARIs to directly influence the genomic behavior of prostate cancer, leading to aggressive and more lethal disease. But prior randomized controlled trials show at most a small increase in the incidence of more aggressive disease, a finding which is likely due to detection bias [3]. While this explanation is still possible based on the study's observational design, a more likely explanation is the delay in diagnosis in men taking 5-ARIs, related to the misinterpretation of their artificially lower PSA values. Although the absolute median del...

Theoretical and experimental determination of optical and magneto-optical properties of LuFe₂single crystal

Hong, S,Zollner, S,Lynch, D.W,Canfield, P.C,Lee, S.J,Lange, R.J,Harmon, B.N,Panchula, A.F 公州大學校 基礎科學硏究所 1998 自然科學硏究 Vol.7 No.-

We have studied the diagonal and off-diagonal optical conductivity of a LuFe2 single crystal grown by the flux method. Using spectroscopic ellipsometry we have measured the dielectric function from 1.5 to 5.5 eV. The magneto-optical parameters (Kerr rotation and ellipticity) from 1.4 to 4.0 eV were obtained using a magneto-optical polar Kerr spectrometer at temperatures between 7 and 295 K and applied magnetic fields up to 1.2T which fully saturates the magnetic moment of LuFe2. We describe the apparatus and evaluate the off-diagonal conductivity components from the data. Theoretical calculations of optical conductivities and magneto-optical parameters were performed using the tight binding-linear muffin tin orbitals method within the local spin density approximation. When lifetime broadening is included, the calculations agree well with the experimental data.

Crystal-field excitations and spin-phonon interactions inDyNi2B2C: Raman scattering study

Rho, Heesuk,Klein, Miles V.,Canfield, Paul C. American Physical Society 2010 Physical review. B, Condensed matter and materials Vol.82 No.6

Development of intermediate temperature sodium nickel chloride rechargeable batteries using conventional polymer sealing technologies

Chang, Hee Jung,Lu, Xiaochuan,Bonnett, Jeff F.,Canfield, Nathan L.,Son, Sori,Park, Yoon-Cheol,Jung, Keeyoung,Sprenkle, Vincent L.,Li, Guosheng Elsevier 2017 Journal of Power Sources Vol.348 No.-

<P><B>Abstract</B></P> <P>Developing advanced and reliable electrical energy storage systems is critical to fulfill global energy demands and stimulate the growth of renewable energy resources. Sodium metal halide batteries have been under serious consideration as a low cost alternative energy storage device for stationary energy storage systems. Yet, there are number of challenges to overcome for the successful market penetration, such as high operating temperature and hermetic sealing of batteries that trigger an expensive manufacturing process. Here we demonstrate simple, economical and practical sealing technologies for Na-NiCl<SUB>2</SUB> batteries operated at an intermediate temperature of 190 °C. Conventional polymers are implemented in planar Na-NiCl<SUB>2</SUB> batteries after a prescreening test, and their excellent compatibilities and durability are demonstrated by a stable performance of Na-NiCl<SUB>2</SUB> battery for more than 300 cycles. The sealing methods developed in this work will be highly beneficial and feasible for prolonging battery cycle life and reducing manufacturing cost for Na-based batteries at elevated temperatures (<200 °C).</P> <P><B>Highlights</B></P> <P> <UL> <LI> Conventional polymers were adopted as sealing materials for Na-NiCl<SUB>2</SUB> batteries. </LI> <LI> Selected polymers showed excellent compatibility with sodium and melts at 190 °C. </LI> <LI> Batteries with polymer seals showed stable performances over 300 cycles. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Nonlinear Response Structural Optimization of a Joined Wing Using Equivalent Loads

Kim, Y.I.,Park, G.J.,Kolonay, R.M.,Blair, M.,Canfield, R.A. AMERICAN INST OF AERONAUTICS AND ASTRONAUTICS 2008 AIAA journal Vol.46 No.11