168 research outputs found
Strategi Penurunan Non Revenue Water (NRW) melalui Analisis Neraca Air dan Indikator Kinerja NRW pada Jaringan Distribusi SPAM Cabang Karawang
Perumdam Tirta Tarum as a BUMD with healthy performance and has FCR (Full Cost Recovery), but the NRW (Non Revenue Water) score is still quite high at 32.16%. The Karawang branch is the largest contributor to the volume of water loss, around 33% of the total water loss in 19 Branches/IKK units in other service areas. This study uses water balance analysis methods and NRW performance indicators to formulate recommendations for NRW reduction programs. Annual water loss during the period April 2022 to March 2023 was 23.96% with a loss volume of 2,343,756m3/12 months. The percentage of physical water loss is 18.49% and non-physical water loss is 5.47%. When converted to cost values, the annual loss of non-physical water is Rp.2,610,791,315.- and the annual loss of physical water is Rp.8,640,197,936.-. Physical loss is classified as category C performance (severe leakage) and the overall ATR performance indicator is classified as category C (poor ATR condition). Recommendations or strategies for handling NRW efficiently at study locations can be formulated after understanding the causes of NRW and the most influencing component factors
Fourier Analysis of Gapped Time Series: Improved Estimates of Solar and Stellar Oscillation Parameters
Quantitative helio- and asteroseismology require very precise measurements of
the frequencies, amplitudes, and lifetimes of the global modes of stellar
oscillation. It is common knowledge that the precision of these measurements
depends on the total length (T), quality, and completeness of the observations.
Except in a few simple cases, the effect of gaps in the data on measurement
precision is poorly understood, in particular in Fourier space where the
convolution of the observable with the observation window introduces
correlations between different frequencies. Here we describe and implement a
rather general method to retrieve maximum likelihood estimates of the
oscillation parameters, taking into account the proper statistics of the
observations. Our fitting method applies in complex Fourier space and exploits
the phase information. We consider both solar-like stochastic oscillations and
long-lived harmonic oscillations, plus random noise. Using numerical
simulations, we demonstrate the existence of cases for which our improved
fitting method is less biased and has a greater precision than when the
frequency correlations are ignored. This is especially true of low
signal-to-noise solar-like oscillations. For example, we discuss a case where
the precision on the mode frequency estimate is increased by a factor of five,
for a duty cycle of 15%. In the case of long-lived sinusoidal oscillations, a
proper treatment of the frequency correlations does not provide any significant
improvement; nevertheless we confirm that the mode frequency can be measured
from gapped data at a much better precision than the 1/T Rayleigh resolution.Comment: Accepted for publication in Solar Physics Topical Issue
"Helioseismology, Asteroseismology, and MHD Connections
Very High Resolution Solar X-ray Imaging Using Diffractive Optics
This paper describes the development of X-ray diffractive optics for imaging
solar flares with better than 0.1 arcsec angular resolution. X-ray images with
this resolution of the \geq10 MK plasma in solar active regions and solar
flares would allow the cross-sectional area of magnetic loops to be resolved
and the coronal flare energy release region itself to be probed. The objective
of this work is to obtain X-ray images in the iron-line complex at 6.7 keV
observed during solar flares with an angular resolution as fine as 0.1 arcsec -
over an order of magnitude finer than is now possible. This line emission is
from highly ionized iron atoms, primarily Fe xxv, in the hottest flare plasma
at temperatures in excess of \approx10 MK. It provides information on the flare
morphology, the iron abundance, and the distribution of the hot plasma.
Studying how this plasma is heated to such high temperatures in such short
times during solar flares is of critical importance in understanding these
powerful transient events, one of the major objectives of solar physics. We
describe the design, fabrication, and testing of phase zone plate X-ray lenses
with focal lengths of \approx100 m at these energies that would be capable of
achieving these objectives. We show how such lenses could be included on a
two-spacecraft formation-flying mission with the lenses on the spacecraft
closest to the Sun and an X-ray imaging array on the second spacecraft in the
focal plane \approx100 m away. High resolution X-ray images could be obtained
when the two spacecraft are aligned with the region of interest on the Sun.
Requirements and constraints for the control of the two spacecraft are
discussed together with the overall feasibility of such a formation-flying
mission
Stability and BPS branes
We define the concept of Pi-stability, a generalization of mu-stability of
vector bundles, and argue that it characterizes N=1 supersymmetric brane
configurations and BPS states in very general string theory compactifications
with N=2 supersymmetry in four dimensions.Comment: harvmac, 18 p
T1 mapping in the rat myocardium at 7 Tesla using a modified CINE inversion recovery sequence
Purpose To evaluate the reproducibility and sensitivity of the modified CINE inversion recovery (mCINE-IR) acquisition on rats for measuring the myocardial T1 at 7 Tesla. Materials and Methods The recently published mCINE-IR acquisition on humans was applied on rats for the first time, enabling the possibility of translational studies with an identical sequence. Simulations were used to study signal evolution and heart rate dependency. Gadolinium phantoms, a heart specimen and a healthy rat were used to study reproducibility. Two cryo-infarcted rats were scanned to measure late gadolinium enhancement (LGE). Results In the phantom reproducibility studies the T1 measurements had a maximum coefficient of variation (COV) of 1.3%. For the in vivo reproducibility the COV was below 5% in the anterior cardiac segments. In simulations with phantoms and specimens, a heart rate dependency of approximately 0.5 ms/bpm was present. The T1 maps of the cryo-infarcted rats showed a clear lowering of T1 in de LGE region. Conclusion The results show that mCINE-IR is highly reproducible and that the sensitivity allows detecting T1 changes in the rat myocardium
Extreme Ultra-Violet Spectroscopy of the Lower Solar Atmosphere During Solar Flares
The extreme ultraviolet portion of the solar spectrum contains a wealth of
diagnostic tools for probing the lower solar atmosphere in response to an
injection of energy, particularly during the impulsive phase of solar flares.
These include temperature and density sensitive line ratios, Doppler shifted
emission lines and nonthermal broadening, abundance measurements, differential
emission measure profiles, and continuum temperatures and energetics, among
others. In this paper I shall review some of the advances made in recent years
using these techniques, focusing primarily on studies that have utilized data
from Hinode/EIS and SDO/EVE, while also providing some historical background
and a summary of future spectroscopic instrumentation.Comment: 34 pages, 8 figures. Submitted to Solar Physics as part of the
Topical Issue on Solar and Stellar Flare
Software engineering processes for self-adaptive systems
In this paper, we discuss how for self-adaptive systems some activities that traditionally occur at development-time are moved to run-time. Responsibilities for these activities shift from software engineers to the system itself, causing the traditional boundary between development-time and run-time to blur. As a consequence, we argue how the traditional software engineering process needs to be reconceptualized to distinguish both development-time and run-time activities, and to support designers in taking decisions on how to properly engineer such systems. Furthermore, we identify a number of challenges related to this required reconceptualization, and we propose initial ideas based on process modeling. We use the Software and Systems Process Engineering Meta-Model (SPEM) to specify which activities are meant to be performed off-line and on-line, and also the dependencies between them. The proposed models should capture information about the costs and benefits of shifting activities to run-time, since such models should support software engineers in their decisions when they are engineering self-adaptive systems
Exploring metabolic responses of potato tissue induced by electric pulses
In this study, we investigated the metabolic
responses of potato tissue induced by pulsed electric field
(PEF). Potato tissue was subjected to field strengths ranging
from 30 to 500 V/cm, with a single rectangular pulse of 10 μs,
100 μs, or 1 ms. Metabolic responses were monitored using
isothermal calorimetry, changes on electrical resistance during
the delivery of the pulse, as well as impedance measurements.
Our results show that the metabolic response involves oxygen
consuming pathways as well as other unidentified events that
are shown to be insensitive to metabolic inhibitors such as
KCN and sodium azide. The metabolic response is strongly
dependent on pulsing conditions and is independent of the
total permeabilization achieved by the pulse. Evidence shows
that calorimetry is a simple and powerful method for
exploring conditions for metabolic stimulation, providing
information on metabolic responses that can not be obtained
from electrical measurements. This study set the basis for
further investigations on defense-related consequences of
PEF-induced stress.Sparbanksstiftelsen Färs & Frosta (Sweden).Fundação para a Ciência e a Tecnologia (FCT).Lund University (Sweden).Department of Cell and Organism Biology; Department of Plant Biochemistry
Measurement of the B0-anti-B0-Oscillation Frequency with Inclusive Dilepton Events
The - oscillation frequency has been measured with a sample of
23 million \B\bar B pairs collected with the BABAR detector at the PEP-II
asymmetric B Factory at SLAC. In this sample, we select events in which both B
mesons decay semileptonically and use the charge of the leptons to identify the
flavor of each B meson. A simultaneous fit to the decay time difference
distributions for opposite- and same-sign dilepton events gives ps.Comment: 7 pages, 1 figure, submitted to Physical Review Letter
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