1,554 research outputs found
The House of Kwee Sik Poo an Indonesian-Chinese Merchant From Pasuruan
The Kwee family is an old Indonesian-Chinese family from Pasuruan, in East Java, and one of a few merchant families of either Chinese or Arab ethnic origin which led successful lives in this small town in the nineteenth century. From their Chinese ancestral village, Liu Chuan in Fujian province, China, a Kwee ancestor travelled to Southeast Asia and settled in Pasuruan, probably in the eighteen century. As with many families who held important positions in the ethnic Chinese community, it also owned large homes, mostly in a mixed architectural style, called āeclecticismā and later in what was known as āthe Indies-empire styleā. The early family history is still clouded in mystery, as not much concrete information has survived. Its descendants worked hard and prospered and dealt among economic undertakings such as sugar production, opium sales, buying and selling of property and land as well as running pawnshops
Laser power stabilization for second-generation gravitational wave detectors
We present results on the power stabilization of a Nd:YAG laser in the frequency band from 1 Hz to 100 kHz. High-power, low-noise photodetectors are used in a dc-coupled control loop to achieve relative power fluctuations down to 5Ć10ā9 Hzā1/2 at 10 Hz and 3.5Ć10ā9 Hzā1/2 up to several kHz, which is very close to the shot-noise limit for 80 mA of detected photocurrent on each detector. We investigated and eliminated several noise sources such as ground loops and beam pointing. The achieved stability level is close to the requirements for the Advanced LIGO gravitational wave detector
Electromagnetic Pulse Welded Aluminium to Copper Sheet Joints: Morphological and Mechanical Characterization
This study investigated joining of Al to Cu sheets by electromagnetic pulse welding, which
is a solid-state welding process that uses electromagnetic forces to join materials. The
interfacial morphology and mechanical properties of the Al/Cu joints were analysed and
related to the welding process parameters. The centre section of the Al/Cu joints evolved
from a non-welded to a welded zone. The welded zone started with a wavy interface,
consisting of thick interfacial layers with defects and evolved to a relatively flat interface
without an interfacial layer. Interfacial phases resulted from solid-state mechanical mixing
and/or very localised interfacial heating. The interfacial layers had a thickness ranging
from 2-39 Ī¼m, an interface waviness amplitude up to 11 Ī¼m and contained 31-75 wt% Cu.
The interfacial layer thickness and the weld length are determined by both the discharge
energy and the stand-off distance. A trade-off existed between a homogeneous interface
and the maximum weld length when the stand-off distance is changed. The interfacial layer
exhibited an increased hardness compared to Al and Cu. A higher tensile force, up to
4,9 kN, was achieved at a higher energy and a lower stand-off distance. One of the factors
determining the tensile force was the width of the welded area
Optical ac coupling to overcome limitations in the detection of optical power fluctuations
A high-sensitivity detection method for optical power fluctuations is demonstrated based on photodetection in reflection of an optical resonator with a specific impedance matching. That resonator is used to reduce the carrier power reflected by the resonator while preserving the power fluctuation sidebands for frequencies above the resonator bandwidth. A sensitivity of 7Ć10ā10 Hzā1/2 for relative power fluctuations was achieved with only 3 mA of detected photocurrent and 99.6% of the power remained for downstream experiments. As in the widely used ac coupling of electrical signals, this technique overcomes dynamic-range limits and reduces detector noise associated with large carrier amplitudes of the optical field
Conversion of brain cytosol profile from fetal to adult type during the perinatal period: Taurine-NAA exchange
Mammals face drastic environmental changes at birth. Appropriate adjustments of various systems must take place rapidly to accommodate this once in a life time event. The brain undergoes significant adjustments as well, the most obvious of which is in its need to meet the drastic increase in energy consumption at the neuronal cell membrane due to the explosive increase in neural activities after birth. Actual changes were found to be taken place in two systems, namely, acid base balance control and cytosolic energy transport. The adjustments are accomplished by converting cytosol microenvironment from a taurine rich fetal type environment to an N-acetyl-aspartate (NAA) rich adult type environment during the post-natal period. High concentrations of taurine are necessary to provide effective buffering in the fetal brain, because the fetus cannot utilize the adult type of pCO2 dependent acidābase balance control system, namely respiration driven pCO2 changes. To accommodate the significantly higher demand of energy consumption at the membrane due to the increased neuronal activities, taurine has to be replaced by NAA, since the latter facilitates HEP transport from mitochondria to the membrane by passive diffusion
Laser beam quality and pointing measurement with an optical resonator
We present a compact diagnostic breadboard that is based on an optical ring resonator for measuring beam quality and pointing of single-frequency continuous wave lasers at a wavelength of 1064 nm. To determine the beam quality of the coherent test beam, this optical resonator is used to perform a mode decomposition into Hermite-Gaussian modes. For our laser system, a power fraction in the fundamental Gaussian mode of 97.2%Ā±0.2% was measured. Residual misalignment and mis-mode-matching to the resonator as well as the astigmatism and/or ellipticity of the test beam have been determined. Numerical simulations showed that measurements of the M2 factor and transversal intensity distribution are not suitable for determining this power fraction. To measure the beam pointing, the fundamental mode of the optical resonator was used as a stable reference. The pointing of the test beam was measured with the differential wave front sensing technique up to Fourier frequencies of 1 kHz with a sensitivity to relative pointing of |epsilon|=1Ć10ā6/sqrt(Hz)
The Clusters AgeS Experiment (CASE). I. V209 omega Cen - An Eclipsing Post-Common Envelope Binary in the Globular Cluster omega Cen
We use photometric and spectroscopic observations of the detached eclipsing
binary V209 omega Cen to derive the masses, radii, and luminosities of the
component stars. The system exhibits total eclipses and, based on the measured
systemic velocity and the derived distance, is a member of the globular cluster
omega Cen. We obtain 0.945 +/- 0.043 Msun, 0.983 +/- 0.015 Rsun and 6.68 +/-
0.88 Lsun for the cooler, but larger and more luminous primary component. The
secondary component has 0.144 +/- 0.008 Msun, 0.425 +/- 0.008 Rsun and 2.26 +/-
0.28 Lsun. The effective temperatures are estimated at 9370 K for the primary
and at 10866 K for the secondary. On the color-magnitude diagram of the
cluster, the primary component occupies a position between the tip of the blue
straggler region and the extended horizontal branch while the secondary
component is located close to the red border of the area occupied by hot
subdwarfs. However, its radius is too large and its effective temperature is
too low for it to be an sdB star. We propose a scenario leading to the
formation of a system with such unusual properties with the primary component
``re-born'' from a former white dwarf which accreted a new envelope through
mass transfer from its companion. The secondary star has lost most of its
envelope while starting its ascent onto the sub-giant branch. It failed to
ignite helium in its core and is currently powered by a hydrogen burning shell.Comment: 24 pages, 9 figures, AJ, in pres
The effect of consumer perceptions towards intention to buy air tickets online in Malaysia
Abstract As the airline industry struggles to be profitable in the face of high operating costs and intense competition, electronic ticketing has emerged to be an effective way to reduce costs. While market research shows an increasing trend among travellers to book air tickets online, they are mostly from advanced nations such as the United States and United Kingdom. Online booking is somewhat lower in Malaysia. To increase online ticket purchases in Malaysia, it is imperative to understand the factors that influence consumersā buying intention. Academic research remains limited in Malaysia. Therefore, this paper reviews the literature on the main variables influencing online buying intention. It starts with an overview of the airline business environment, and air travellersā behaviour pertaining to tickets booking. Subsequently, the Technology Acceptance Model and its relevant variables are discussed. Next, the research methodology and conceptual model are presented. Finally, the paper concludes with recommendations for airline companies.
Keywords: air tickets, online, intentio
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