Monotonic Prefix Consistency in Distributed Systems

We study the issue of data consistency in distributed systems. Specifically, we consider a distributed system that replicates its data at multiple sites, which is prone to partitions, and which is assumed to be available (in the sense that queries are always eventually answered). In such a setting, strong consistency, where all replicas of the system apply synchronously every operation, is not possible to implement. However, many weaker consistency criteria that allow a greater number of behaviors than strong consistency, are implementable in available distributed systems. We focus on determining the strongest consistency criterion that can be implemented in a convergent and available distributed system that tolerates partitions. We focus on objects where the set of operations can be split into updates and queries. We show that no criterion stronger than Monotonic Prefix Consistency (MPC) can be implemented.Comment: Submitted pape

Optimizing Glass Design: The Role of Computational Wind Engineering & Advanced Numerical Analysis

Wind induced pressure is a major design consideration for glazing design. However, the effects of façade geometry and urban terrain on wind loading are often difficult to quantify without costly and time-consuming wind tunnel testing.  Accurate 3-dimensional data, covering most major cities, is becoming increasingly accessible, and such models are ideal to support numerical modelling of environmental effects on the built environment, especially if such modelling attempts to capture the geometric effects of the cityscape.  A new methodology to assess the effects of wind loads on the structural strength of glass using transient, geometrically non-linear analyses and improved glass failure prediction models is presented.  A description is provided for both the calculation of wind-induced façade loads, and the development and employment of a finite element (FE) solver to model façade performance.&nbsp

Kinetics and mechanism of proton transport across membrane nanopores

We use computer simulations to study the kinetics and mechanism of proton passage through a narrow-pore carbon-nanotube membrane separating reservoirs of liquid water. Free energy and rate constant calculations show that protons move across the membrane diffusively in single-file chains of hydrogen-bonded water molecules. Proton passage through the membrane is opposed by a high barrier along the effective potential, reflecting the large electrostatic penalty for desolvation and reminiscent of charge exclusion in biological water channels. At neutral pH, we estimate a translocation rate of about 1 proton per hour and tube.Comment: 4 pages, 4 figure

Increasing Nurse Awareness of a Breastfeeding and Substance Use Disorder Guideline to Improve Rates of Breast Milk and Skin to Skin Usage: A Quality Improvement Initiative​

Neonatal opioid withdrawal syndrome (NOWS) is related to opioid exposure in utero, and cases of NOWS have been increasing. In Tennessee in 2020, 824 newborns were born with NOWS. NOWS treatment involves pharmacological and nonpharmacological treatment. Breastfeeding, a nonpharmacological treatment, decreases the need and length for pharmacological treatment, the length of stay, and NOWS symptoms. Skin-to-skin may also reduce symptoms of NOWS. This quality improvement (QI) project involved implementing an Opioid Use Disorder Toolkit from the Tennessee Initiative for Perinatal Quality Care (TIPQC) and specifically educating staff nurses in a Women and Infant’s Department in a regional medical center on a substance use disorder and breastfeeding guideline. The guideline followed the American Academy of Pediatrics, Academy of Breastfeeding Medicine, and the Association of Women’s Health, Obstetric, and Neonatal Nurses’ recommendations that mothers stable on medication assisted treatment should be encouraged to breastfeed. Education occurred via an online educational module and display of unit flyers. A pre-and post-module survey was sent to nursing staff to assess awareness and use of the guideline. We saw an increase in awareness of the guideline from 91% to 97%. We also saw an increase in breastfeeding at discharge, a decrease in NOWS diagnosis, and a decrease in the length of pharmacologic treatment. Overall, this QI project helped increase nurses’ knowledge of breastfeeding in mothers with substance use disorders. We found a clinically significant decrease in NOWS diagnosis, a decrease in the length of treatment, and an increase in breastfeeding rates at discharge

The mutual coherence of simultaneously injection-locked laser diode arrays

The modulus of the mutual coherence function, {vert bar}g{sub 12}({tau}){vert bar}, has been measured for two physically separated laser diode arrays that were simultaneously injection locked to the same master laser. The measured value {vert bar}g{sub 12}({tau}){vert bar} = 0.96 {plus minus} 0.06, is close to ideal. 2 figs

Muon-spin-rotation measurements of the penetration depth in Li_2Pd_3B

Measurements of the magnetic field penetration depth $\lambda$ in the ternary boride superconductor Li$_2$Pd$_3$B ($T_c\simeq7.3$ K) have been carried out by means of muon-spin rotation ($\mu$SR). The absolute values of $\lambda$, the Ginzburg-Landau parameter $\kappa$, and the first $H_{c1}$ and the second $H_{c2}$ critical fields at T=0 obtained from $\mu$SR were found to be $\lambda(0)=252(2)$ nm, $\kappa(0)=27(1)$, $\mu_0H_{c1}(0)=9.5(1)$ mT, and $\mu_0H_{c2}(0)=3.66(8)$ T, respectively. The zero-temperature value of the superconducting gap $\Delta_0=$1.31(3) meV was found, corresponding to the ratio $2\Delta_0/k_BT_c=4.0(1)$. At low temperatures $\lambda(T)$ saturates and becomes constant below $T\simeq 0.2T_c$, in agreement with what is expected for s-wave BCS superconductors. Our results suggest that Li$_2$Pd$_3$B is a s-wave BCS superconductor with the only one isotropic energy gap.Comment: 6 pages, 7 figure

The Proliferation of Special Accounting Items: A Threat to Corporate Credibility

Betty L. Brewer, DBA, CFP, is associate professor of finance, Department of Business and Economics, North Carolina A&T State University, Greensboro, NC 27411. Robert J. Angell, DBA, is professor of finance, Department of Business Administration, School of Business and Economics, North Carolina A&T State University, Greensboro, NC 27411. R. David Mautz, Jr., Ph.D., CPA, is associate professor of accounting, Department of Accounting, School of Business and Economics, North Carolina A&T State University, Greensboro, NC 27411

Environmental/Thermal Barrier Coatings for Ceramic Matrix Composites: Thermal Tradeoff Studies

Recent interest in environmental/thermal barrier coatings (EBC/TBCs) has prompted research to develop life-prediction methodologies for the coating systems of advanced high-temperature ceramic matrix composites (CMCs). Heat-transfer analysis of EBC/TBCs for CMCs is an essential part of the effort. It helps establish the resulting thermal profile through the thickness of the CMC that is protected by the EBC/TBC system. This report documents the results of a one-dimensional analysis of an advanced high-temperature CMC system protected with an EBC/TBC system. The one-dimensional analysis was used for tradeoff studies involving parametric variation of the conductivity; the thickness of the EBC/TBCs, bond coat, and CMC substrate; and the cooling requirements. The insight gained from the results will be used to configure a viable EBC/TBC system for CMC liners that meet the desired hot surface, cold surface, and substrate temperature requirements