4,052 research outputs found
Application of a simplified probe feed impedance formula to the design of a dual frequency patch antenna
A simplified probe feed input impedance for a rectangular patch antenna based on the Green's function is used to design a dual frequency matched antenna. The predicted results at design frequencies of 1.9 and 2.4 GHz are in close agreement with experimental measurements
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An investigation into the effects of computer integrated manufacturing systems in the productivity of SMEs in Pakistan
The current dynamic and turbulent manufacturing environment has forced companies that compete globally to change their traditional methods of conducting business [Producer to consumer]. Recent developments in manufacturing and business operations have lead to the adoption of Computer Integrated Manufacturing (CIM) technologies that are based on systems and processes that support global competitiveness, especially for Small and Medium Enterprises (SMEs). Organizations and SMEs in particular need to re-evaluate every aspect of their manufacturing strategy and quickly move towards a CIM based environment where manufacturing technologies, business strategies and processes are integrated together. This paper highlights the development of a CIM adoption model that has resulted from empirical work generated from SMEs in Pakistan. The model consists of the parameters such as Top Management Support, System Integration, Marketing, and over all performance
Yet another cause of chronic viral hepatitis?
The clinical features, course and histology of liver in 20 patients; mostly middle aged to elderly females, closely resembling chronic Non A Non B hepatitis is presented. They presented quite late in their disease and therefore, complications such as variceal bleeds, ascites and encephalopathy were frequent. Our patients were negative for hepatitis B and C virus serology. Metabolic and immune causes of chronic liver disease were also ruled out. To the best of our knowledge, this is the first study of its kind elaborating the clinical features, course and histology of liver in chronic Non B Non C hepatitis and raises a number of questions as to the nature of the infecting virus and the epidemiology of disease
Flow induced vibration of a square cylinder with high scruton number
Flow over a square cylinder is numerically studied to understand the effect of reduced velocity to the transverse oscillation under the influence of high Scruton number elastic system of 4.316. For low reduced velocities, the transverse oscillation behavior can be grouped in the initial branch region. In this region, the motion is mainly controlled by the lift fluctuation. For intermediate reduced velocities, the transverse oscillation behavior is grouped in the lower branch region. In this region, its natural frequency slowly becomes significant. For high reduced velocities, the galloping region is observed. In this region, the natural frequency dominated the shape of the amplitude oscillation
Comparative study on energy extraction from vibrating square cylinder
In this paper, the prospect of harvesting energy from flow induced-vibration of a square cylinder is assessed. The extraction of energy from the flow is attained by mounting the square cylinder on a one-degree elastic system with a massdamping (m*ζ) of 2.75. OpenFOAM®, an open source CFD package is used to model the flow induced motion of the square cylinder. A theoretical formulation to estimate the lift force acting on the square cylinder is derived to confirm the results obtained by the simulation. A good agreement between the results is obtained. The amplitude vibration and lift force are then used to estimate the power induced by the oscillating square cylinder. Energy in the micro scale range can be harvested from this flow induced-vibration system. This type of alternative green energy is suitable for the micro energy harvester system required for sensors in many engineering structure for health monitoring purpose
Slow electron holes in the Earth's magnetosheath
We present a statistical analysis of electrostatic solitary waves observed
aboard Magnetospheric Multiscale spacecraft in the Earth's magnetosheath.
Applying single-spacecraft interferometry to several hundred solitary waves
collected in about two minute intervals, we show that almost all of them have
the electrostatic potential of positive polarity and propagate quasi-parallel
to the local magnetic field with plasma frame velocities of the order of 100
km/s. The solitary waves have typical parallel half-widths from 10 to 100 m
that is between 1 and 10 Debye lengths and typical amplitudes of the
electrostatic potential from 10 to 200 mV that is between 0.01 and 1\% of local
electron temperature. The solitary waves are associated with quasi-Maxwellian
ion velocity distribution functions, and their plasma frame velocities are
comparable with ion thermal speed and well below electron thermal speed. We
argue that the solitary waves of positive polarity are slow electron holes and
estimate the time scale of their acceleration, which occurs due to interaction
with ions, to be of the order of one second. The observation of slow electron
holes indicates that their lifetime was shorter than the acceleration time
scale. We argue that multi-spacecraft interferometry applied previously to
these solitary waves is not applicable because of their too-short spatial
scales. The source of the slow electron holes and the role in electron-ion
energy exchange remain to be established
Statistically Designed Bioprocess for Enhanced Production of Alkaline Protease in Bacillus cereus HP_RZ17
491-498Alkaline protease is one of the bulk enzymes having wide commercial demand for various applications. It is commercially produced by a submerged fermentation process employing various bacteria, Bacillus sp. being the most widely used species. Statistical optimization of the process for the production of alkaline proteases from rhizospheric bacteria and its application in the biocontrol of plant pathogens has not been explored fully and needs to be studied for the development of efficient bioprocess. We report the enhanced production of alkaline protease in the minimal salt medium (MSM) optimized using statistical approaches such as Plackett Burman Design (PBD) and Response Surface Methodology (RSM). In the first step; PBD, among the total eight variables, three variables namely, yeast extract (pppBacillus cereus HP_RZ17. These three variables were further analyzed in the second step i.e. Central Composite Design (CCD) of RSM. The optimum yield of alkaline protease by B. cereus HP_RZ17 (130.72 UmL-1) was obtained under the optimal conditions such as yeast extract (0.899% w/v), fructose (0.873% w/v), and pH (11.25) of production media. The statistically optimized values of variables used for the scale-up of the process at 5 L capacity bioreactor enhanced the alkaline protease yield (132.48 UmL-1) by 1.09 fold vis-à-vis un-optimized protocol (121.96 UmL-1) in B. cereus HP_RZ17
Application of Hazard Functions to Investigate Recurrence After Curative-Intent Resection for Hepatocellular Carcinoma
Background: Defining patterns and risk of recurrence can help inform surveillance strategies and patient counselling. We sought to characterize peak hazard rates (pHR) and peak time of recurrence among patients who underwent resection of hepatocellular carcinoma (HCC).
Methods: 1434 patients who underwent curative-intent resection of HCC were identified from a multi-institutional database. Hazard, patterns, and peak rates of recurrence were characterized.
Results: The overall hazard of recurrence peaked at 2.4 months (pHR: 0.0384), yet varied markedly. The incidence of recurrence increased with Barcelona Clinic Liver Cancer (BCLC) stage 0 (29%), A (54%), and B (64%). While the hazard function curve for BCLC 0 patients was relatively flat (pHR: 400 ng/mL: 36.3%) and Tumor Burden Score (low: 73.7% vs. medium: 50.6% vs. high: 24.2%) (both p < 0.001).
Conclusion: Recurrence hazard rates for HCC varied substantially relative to both time and intensity/peak rates. TBS and AFP markedly impacted patterns of hazard risk of recurrence.info:eu-repo/semantics/publishedVersio
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