Synthesis of Planar Stiffness

In this work the problem of designing systems of springs to achieve a desired stiffness matrix is considered. Only planar configurations are studied. After a brief section outlining the theory of the stiffness of planar systems the planar stiffness matrix of three typical design elements are found, simple springs, beams and pairs of stretched springs. A final section shows how arbitrary stiffness matrices can be achieved using three simple springs or two stretched spring pairs

The Contributing Factors to Student Nurse Medication Administration Errors and Near Misses in the Clinical Setting as Identified By Clinical Instructors

The report, To Err is Human, by the Institutes of Medicine (IOM, 2000) brought attention to medication safety in the United States healthcare system. While advances have been made in patient safety, including electronic medication dispensing systems, electronic medication administration records, and scanning systems, it is estimated that 7,000 to 9,000 people die each year due to medication errors (Tariq et al., 2019). The medication administration process involves steps from prescribing to administration. However, nurses administering the medications are the final check point. James Reasons’ Swiss Cheese Model of Accident Causation illustrates the role that systems play in medical errors. The purpose of this dissertation is to determine the factors that contribute to undergraduate, prelicensure student nurse medication errors and near misses as identified by clinical instructors and the interventions that may help to mitigate these factors. The top 5 most common contributing factors of medication errors and near misses were ‘students having limited knowledge about medications,’ ‘the names of many medications are similar.’ ‘all medications for one team of patients cannot be passed within an accepted time frame,’ ‘the packaging of many medications is similar,’ and ‘students do not receive enough instruction on medications.’ The results have implications in nursing education and the potential to impact patient safety

An airfoil for general aviation applications

A new airfoil, the NLF(1)-0115, has been recently designed at the NASA Langley Research Center for use in general-aviation applications. During the development of this airfoil, special emphasis was placed on experiences and observations gleaned from other successful general-aviation airfoils. For example, the flight lift-coefficient range is the same as that of the turbulent-flow NACA 23015 airfoil. Also, although beneficial for reducing drag and having large amounts of lift, the NLF(1)-0115 avoids the use of aft loading which can lead to large stick forces if utilized on portions of the wing having ailerons. Furthermore, not using aft loading eliminates the concern that the high pitching-moment coefficient generated by such airfoils can result in large trim drags if cruise flaps are not employed. The NASA NLF(1)-0115 has a thickness of 15 percent. It is designed primarily for general-aviation aircraft with wing loadings of 718 to 958 N/sq m (15 to 20 lb/sq ft). Low profile drag as a result of laminar flow is obtained over the range from c sub l = 0.1 and R = 9x10(exp 6) (the cruise condition) to c sub l = 0.6 and R = 4 x 10(exp 6) (the climb condition). While this airfoil can be used with flaps, it is designed to achieve c(sub l, max) = 1.5 at R = 2.6 x 10(exp 6) without flaps. The zero-lift pitching moment is held at c sub m sub o = 0.055. The hinge moment for a .20c aileron is fixed at a value equal to that of the NACA 63 sub 2-215 airfoil, c sub h = 0.00216. The loss in c (sub l, max) due to leading edge roughness, rain, or insects at R = 2.6 x 10 (exp 6) is 11 percent as compared with 14 percent for the NACA 23015

On the use of Klein quadric for geometric incidence problems in two dimensions

We discuss a unified approach to a class of geometric combinatorics incidence problems in $2D$, of the Erd\"os distance type. The goal is obtaining the second moment estimate, that is given a finite point set $S$ and a function $f$ on $S\times S$, an upper bound on the number of solutions of $$f(p,p') = f(q,q')\neq 0,\qquad (p,p',q,q')\in S\times S\times S\times S. \qquad(*)$$ E.g., $f$ is the Euclidean distance in the plane, sphere, or a sheet of the two-sheeted hyperboloid. Our tool is the Guth-Katz incidence theorem for lines in $\mathbb{RP}^3$, but we focus on how the original $2D$ problem is made amenable to it. This procedure was initiated by Elekes and Sharir, based on symmetry considerations. However, symmetry considerations can be bypassed or made implicit. The classical Pl\"ucker-Klein formalism for line geometry enables one to directly interpret a solution of $(*)$ as intersection of two lines in $\mathbb{RP}^3$. This allows for a very brief argument extending the Euclidean plane distance argument to the spherical and hyperbolic distances. We also find instances of the question $(*)$ without underlying symmetry group. The space of lines in the three-space, the Klein quadric $\mathcal K$, is four-dimensional. We start out with an injective map $\mathfrak F:\,S\times S\to\mathcal K$, from a pair of points in $2D$ to a line in $3D$ and seek a combinatorial problem in the form $(*)$, which can be solved by applying the Guth-Katz theorem to the set of lines in question. We identify a few new such problems and generalise the existing ones.Comment: Theorem 5', implicit in the earlier verisons has been stated explicitly in this ArXiv version, giving a family of applications of the Guth-Katz theorem to sum-product type quantities, with no underlying symmetry grou

Excitonic insulator states in molecular functionalized atomically-thin semiconductors

The excitonic insulator is an elusive electronic phase exhibiting a correlated excitonic ground state. Materials with such a phase are expected to have intriguing properties such as excitonic high-temperature superconductivity. However, compelling evidence on the experimental realization is still missing. Here, we theoretically propose hybrids of two-dimensional semiconductors functionalized by organic molecules as prototypes of excitonic insulators, with the exemplary candidate WS2-F6TCNNQ. This material system exhibits an excitonic insulating phase at room temperature with a ground state formed by a condensate of interlayer excitons. To address an experimentally relevant situation, we calculate the corresponding phase diagram for the important parameters: temperature, gap energy, and dielectric environment. Further, to guide future experimental detection, we show how to optically characterize the different electronic phases via far-infrared to terahertz (THz) spectroscopy