34 research outputs found
MR and CT techniques
Magnetic resonance imaging (MRI) and computed
tomography (CT) are routinely used in
female pelvis imaging. MRI is primarily useful
for locoregional characterization of benign
and malignant diseases. CT is less accurate in
locoregional evaluation, but remains useful in
the follow-up of treated gynecological malignancies,
as well as in the setting of emergency
and in the guidance of biopsies. Although
transabdominal and transvaginal ultrasonography
(US) is not under the scope of this chapter,
it remains the first-line imaging method
for most gynecological conditions.info:eu-repo/semantics/publishedVersio
Tailoring Surface Adsorption and Reactivity of Fullerene-Based Compounds: A Theoretical Probe into C<sub>2</sub>–Gas–Fullerene Surface Interactions
Density functional theory investigations
of palladium and nickel
substituted fullerenes (C<sub>59</sub>M; M = Pd/Ni) were carried out
probing the changes in their surface adsorption potential. Structure
and bonding in the proposed heterofullerenes were established with
insights into metal–carbon bond character, stability, and adsorption
potential. C<sub>2</sub>‑gases were used as probe gases for
adsorption tests. Adsorption of acetylene, ethylene, and ethane was
studied with different sites over pure and heterofullerenes. Adsorption
of acetylene was stronger than the adsorption of ethylene and ethane
over C<sub>60</sub> with the bridge site sharing hexagonal rings being
the energetically favored adsorption site. Surface modification of
the fullerene molecule with a foreign metal enhanced the gas-substrate
(C<sub>2</sub>-heterofullerene) interactions. Enhanced surface interactions
and differential adsorption behavior of different heterofullerenes
made them potential candidates as selective acetylene hydrogenation
catalysts. Free energy landscapes for hydrogenation of acetylene and
ethylene over all three compounds were developed. The energy barriers
for various elementary steps during hydrogenation were significantly
smaller over the heterofullerenes when compared to those over C<sub>60</sub>. Whereas substitution of either metals resulted in a reduction
of activation barriers, the activation barriers for post-ethylene
formation reactions were smaller over C<sub>59</sub>Ni making C<sub>59</sub>Pd a good selective acetylene hydrogenation catalyst
Hydraulic Spring Stiffness Testing Machine
In many engineering machines and mechanisms spring is an essential component used for proper functioning of that machine for maximum efficiency, there are many applications of springs in automobile suspension system, IC engine valves , brakes, clutches, measurements of weights, for storing energy such as in spring type accumulator, in shock absorber, in hydraulic components such as hydraulic cylinders, pressure relief valves, flow control valves etc. But according to the our market survey and observations sometimes spring used in above applications having a many defects such as manufacturing defects, processing defects like defects occurs at the time of hardening sometimes this causes the more hardened spring which has more stiffness value and sometimes causes a less stiffness value of spring, hence this creates a problems on the applications of the springs for proper uses and creates a problems in working of that machinecomponents.By considering this problem we can easily measure spring stiffness by using this machine in low cos
Evaluation of Progressive Failure of Composite T-Joint Using Mixed Mode Cohesive Zone Model.
T shaped stiffeners are the most commonly used structures in aerospace components. De-lamination/de-bond initiation followed by its growth is one of the most common reasons for failure in a fiber reinforced composite structure. It is caused by the interlaminar normal and shear stresses between different structural constituents. In a typical structural T-joint, the failure mechanism and location may differ based on the structural design parameters like fillet radius, thickness, layup sequence, filler stiffness, etc. In this study, finite element analysis has been performed using cohesive zone model (CZM) on a composite T-joint to simulate the pull out test conditions. A simplified plane strain model coupled with CZM is proposed, which can evaluate the failure initiation and progression accurately with lesser computational efforts. The final failure occurs at a displacement of 8.04 mm and the computed failure load is 2240 N. The results obtained by the proposed numerical model are validated by experimental results and it is observed that predicted regions of failure, failure displacements and failure load calculated are correlating reasonably well with the experiment
Structural Properties of Nanosized NiFe2O4 for LPG Sensor
Nanocrystalline NiFe2O4 has been synthesized by sol-gel citrate method. The synthesized powder was characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). As found from the XRD line broadening, the crystallite size of the powder was found to be 40 nm. The gas sensing properties were studied for reducing gases such as LPG, CH4, CO and NH3. It was observed that the nanosized NiFe2O4 shows high sensitivity for LPG at an operating temperature 300 oC. Pd incorporation in NiFe2O4 results in a decrease in operating temperature by 100 oC and improves the sensing characteristics in terms of response time