2,253 research outputs found
Evolving IT management frameworks towards a sustainable future
Information Technology (IT) Management Frameworks are a fundamental tool used by IT professionals to efficiently manage IT resources and are globally applied to IT service delivery and management. Sustainability is a recent notion that describes the need for economic, environmental and social development with- out compromising the ability of future generations to meet their own needs; this applies to businesses as well as society in general. Unfortunately, IT Management Frameworks do not take sustainability into account. To the practitioner this paper demonstrates sustainability integration thereby allowing CIOs and IT managers to improve the sustainability of their organisation. To the researcher this paper argues that sustainability concerns need to be provided to IT Management through its integration into the mainstream of IT Management Frameworks. This is demonstrated through the high-level integration of sustainability in Six Sigma, C OBI T, ITIL and PRINCE2
On Extracting Mechanical Properties from Nanoindentation at Temperatures up to 1000C
Alloyed MCrAlY bond coats, where M is usually cobalt and/or nickel, are
essential parts of modern turbine blades, imparting environmental resistance
while mediating thermal expansivity differences. Nanoindentation allows the
determination of their properties without the complexities of traditional
mechanical tests, but was not previously possible near turbine operating
temperatures.
Here, we determine the hardness and modulus of CMSX-4 and an Amdry-386 bond
coat by nanoindentation up to 1000C. Both materials exhibit a
constant hardness until 400C followed by considerable softening,
which in CMSX-4 is attributed to the multiple slip systems operating underneath
a Berkovich indenter.
The creep behaviour has been investigated via the nanoindentation hold
segments. Above 700C, the observed creep exponents match the
temperature-dependence of literature values in CMSX-4. In Amdry-386,
nanoindentation produces creep exponents very close to literature data,
implying high-temperature nanoindentation may be powerful in characterising
these coatings and providing inputs for material, model and process
optimisations
The magnetoresistance of homogeneous and heterogeneous silver-rich silver selenide
The magnetoresistance (MR) effect of the low-temperature phase of silver selenide (-Ag2 + Se) is measured as a function of composition. Very small composition variations in the order of = 10–6 are achieved by coulometric titration and can be performed simultaneously during the MR measurement. A homogeneous Ag2 + Se shows an ordinary magnetoresistance (OMR) effect, which can be well described by the two-band model. For silver selenide with a heterogenous silver excess, we found quite a different MR behavior. Up to a minor silver excess of 1×10–4 10–2) shows again an OMR effect
Covid-19\u27s Effect on Education
The purpose for this paper is to inform the reader of what the effect of the Covid-19 pandemic has on students and teachers along with finding solutions. The biggest concern during this time is if students are meeting the required materials while in school. Many students are falling behind and there needs to be a solution on how to solve this problem. Covid has caused many problems in everyone’s life but, especially in the lives of students. Teachers are struggling to find solutions due to limitations of Nontraditional Instruction and virtual classrooms. Parents and teachers can team up to help one another out and to achieve the goals of their student(s)
Purification of prostaglandin E2-9-oxoreductase from human decidua vera
AbstractProstaglandin E2-9-oxoreductase (PGE2-9-OR), the enzyme which converts prostaglandin E2 (PGE2) to prostaglandin F2α (PGF2α), has been detected in human decidua vera. A 105-fold purification was achieved when the centrifuged homogenate was fractionated sequentially by DEAE—Trisacryl, hydroxyapatite—agarose gel, ultrogel AcA 44 and Matrex gel blue A gel chromatographies. The following kinetic constants for PGE2-9-OR have been obtained. The equilibrium constant with respect to PGE2 is 83 μM, the Michaelis constant, Km, for PGE2 is 80 μM, for NADPH 1.6 μM. The maximal velocity for the forward reaction is V1 = .203 pmol/min. The enzyme was inhibited by progesterone, oestradiol-17β, cortisol and pharmaceutical drugs. An activating effect could be demonstrated with Ca2+ and oxytocin. The occurrence of PGE2-9-OR in the decidua vera suggests that this enzyme may be responsible for the transformation of PGE2 to PGF2α in these tissues. This may be an important mechanism for the initiation and maintenance of uterine contractions
Thermoplastic deformation of silicon surfaces induced by ultrashort pulsed lasers in submelting conditions
A hybrid 2D theoretical model is presented to describe thermoplastic
deformation effects on silicon surfaces induced by single and multiple
ultrashort pulsed laser irradiation in submelting conditions. An approximation
of the Boltzmann transport equation is adopted to describe the laser
irradiation process. The evolution of the induced deformation field is
described initially by adopting the differential equations of dynamic
thermoelasticity while the onset of plastic yielding is described by the von
Mise's stress. Details of the resulting picometre sized crater, produced by
irradiation with a single pulse, are then discussed as a function of the
imposed conditions and thresholds for the onset of plasticity are computed.
Irradiation with multiple pulses leads to ripple formation of nanometre size
that originates from the interference of the incident and a surface scattered
wave. It is suggested that ultrafast laser induced surface modification in
semiconductors is feasible in submelting conditions, and it may act as a
precursor of the incubation effects observed at multiple pulse irradiation of
materials surfaces.Comment: To appear in the Journal of Applied Physic
RNA secondary structure design
We consider the inverse-folding problem for RNA secondary structures: for a
given (pseudo-knot-free) secondary structure find a sequence that has that
structure as its ground state. If such a sequence exists, the structure is
called designable. We implemented a branch-and-bound algorithm that is able to
do an exhaustive search within the sequence space, i.e., gives an exact answer
whether such a sequence exists. The bound required by the branch-and-bound
algorithm are calculated by a dynamic programming algorithm. We consider
different alphabet sizes and an ensemble of random structures, which we want to
design. We find that for two letters almost none of these structures are
designable. The designability improves for the three-letter case, but still a
significant fraction of structures is undesignable. This changes when we look
at the natural four-letter case with two pairs of complementary bases:
undesignable structures are the exception, although they still exist. Finally,
we also study the relation between designability and the algorithmic complexity
of the branch-and-bound algorithm. Within the ensemble of structures, a high
average degree of undesignability is correlated to a long time to prove that a
given structure is (un-)designable. In the four-letter case, where the
designability is high everywhere, the algorithmic complexity is highest in the
region of naturally occurring RNA.Comment: 11 pages, 10 figure
Brief Cognitive Screening Tools for Primary Care Practice
Early detection and diagnosis of Alzheimer’s disease and other cognitive impairment presents as a critical issue facing primary and specialty care providers in Washington State. In order to address the gaps and challenges faced by providers, the Dementia Action Collaborative offers the current paper to provide information and guidance around early detection and diagnosis of memory loss and dementia, including Alzheimer’s disease. At the conclusion of this paper, providers should be able to identify indications and opportunities for detection, appropriate tools, and care pathways for individuals and families affected by cognitive impairment and dementia
Etched graphene quantum dots on hexagonal boron nitride
We report on the fabrication and characterization of etched graphene quantum
dots (QDs) on hexagonal boron nitride (hBN) and SiO2 with different island
diameters. We perform a statistical analysis of Coulomb peak spacings over a
wide energy range. For graphene QDs on hBN, the standard deviation of the
normalized peak spacing distribution decreases with increasing QD diameter,
whereas for QDs on SiO2 no diameter dependency is observed. In addition, QDs on
hBN are more stable under the influence of perpendicular magnetic fields up to
9T. Both results indicate a substantially reduced substrate induced disorder
potential in graphene QDs on hBN
Reduction of Two-Dimensional Dilute Ising Spin Glasses
The recently proposed reduction method is applied to the Edwards-Anderson
model on bond-diluted square lattices. This allows, in combination with a
graph-theoretical matching algorithm, to calculate numerically exact ground
states of large systems. Low-temperature domain-wall excitations are studied to
determine the stiffness exponent y_2. A value of y_2=-0.281(3) is found,
consistent with previous results obtained on undiluted lattices. This
comparison demonstrates the validity of the reduction method for bond-diluted
spin systems and provides strong support for similar studies proclaiming
accurate results for stiffness exponents in dimensions d=3,...,7.Comment: 7 pages, RevTex4, 6 ps-figures included, for related information, see
http://www.physics.emory.edu/faculty/boettcher
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