2,550 research outputs found
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Evaluating several satellite precipitation estimates and global ground-based dataset on Sicily (Italy)
The developing of satellite-based precipitation retrieval systems, presents great potentialities for several applications ranging from weather and meteorological applications to hydrological modelling. Evaluating performances for these estimates is essential in order to understand their real capabilities and suitability related to each application. In this study an evaluation analysis of satellite precipitation retrieval systems has been carried out for the area of Sicily (Italy). Sicily is an island in the Mediterranean sea with a particular climatology and morphology, which is considered as an interesting test site for satellite precipitation products on the European mid-latitude area. A high density rain-gauges network has been used to evaluate selected satellite precipitation products. Sicily has an area of 26,000 km2 and the gauge density of the network considered in this study is about 250 km2/gauge. Four satellite products (CMORPH, PERSIANN, TMPA-RT, PERSIANN-CCS) along with two adjusted products (TMPA and PERSIANN Adjusted) have been selected for the evaluation. Evaluation and comparisons among selected products is performed with reference to the data provided by the gauge network of Sicily and using statistical and visualization tools. Results show that bias is relevant for all satellite products and climatic considerations are reported to address this issue. Moreover bias errors are observed for the adjusted products even though they are reduced respect to only-satellite products. In order to analyze this result, the ground-based precipitation dataset used by adjusted products (GPCC dataset), has been examined and weaknesses arising from spatial sampling of precipitation process have been identified for the study area. Therefore possible issues deriving from using global ground-based datasets for local scales are pointed out from this application. © 2012 SPIE
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Evaluation and comparison of satellite precipitation estimates with reference to a local area in the Mediterranean Sea
Precipitation is one of the major variables for many applications and disciplines related to water resources and the geophysical Earth system. Satellite retrieval systems, rain-gauge networks, and radar systems are complementary to each other in terms of their coverage and capability of monitoring precipitation. Satellite-rainfall estimate systems produce data with global coverage that can provide information in areas for which data from other sources are unavailable. Without referring to ground measurements, satellite-based estimates can be biased and, although some gauge-adjusted satellite-precipitation products have been already developed, an effective way of integrating multi-sources of precipitation information is still a challenge.In this study, a specific area, the Sicilia Island (Italy), has been selected for the evaluation of satellite-precipitation products based on rain-gauge data. This island is located in the Mediterranean Sea, with a particular climatology and morphology, which can be considered an interesting test site for satellite-precipitation products in the European mid-latitude area. Four satellite products (CMORPH, PERSIANN, PERSIANN-CCS, and TMPA-RT) and two GPCP-adjusted products (TMPA and PERSIANN Adjusted) have been selected. Evaluation and comparison of selected products is performed with reference to data provided by the rain-gauge network of the Island Sicilia and by using statistical and graphical tools. Particular attention is paid to bias issues shown both by only-satellite and adjusted products. In order to investigate the current and potential possibilities of improving estimates by means of adjustment procedures using GPCC ground precipitation, the data have been retrieved separately and compared directly with the reference rain-gauge network data set of the study area.Results show that bias is still considerable for all satellite products, then some considerations about larger area climatology, PMW-retrieval algorithms, and GPCC data are discussed to address this issue, along with the spatial and seasonal characterization of results. © 2013 Elsevier B.V
Efektivitas Pendekatan Metakognisi Terhadap Penalaran Matematis Pada Matakuliah Geometri Transformasi
Mastery of geometry transformation is still low, have an impact on learning outcomes are not satisfactory. Some of it is also due to students not understand how to solve the problems of proof in geometry transformation, therefore, students should know the proper way of learning, ranging from planning to solve problems of proof. Therefore, students should be able to think how to think, so good mathematical reasoning ability is required. One approach to learning that students are aware of the way of thinking metacognitive approach. The population in this study was a sophomore Unswagati, selected by cluster sampling technique is one control and one experiment class. Data were obtained through tests of mathematical reasoning and observation sheet. Data processed by descriptive, comparative test sample t-test and regression analysis. The results showed that the effective learning of metacognitive approach to mathematical reasoning students, some indicators are met, namely (1) the mathematical reasoning students achieve classical completeness 73.33 are greater than KKM at 65, (2) the student\u27s activeness on metacognitive approach to learning with a positive effect on mathematical reasoning students by 39.60%, (3) average of mathematical reasoning student in a class experiments (average 73.33) is better than the control class (average 40.38)
Perangkat Pembelajaran Matematika Berbasis Smart (Specific, Measurable, Achievable, Realistic, and Time-bound)
Developing a teaching intruments using a modified model of 4-D (to 3D) Thiagarajan is as follows: (1) Definition, (2) Design, and (3) Development. Teaching instruments was developed (1) Syllabus, (2) Lesson Plan, (3) Module. Data obtained through the sheet validation, test learning achievement. The data were processed with descriptive and comparative analysis sample t test. Development process instruments resulted in: 1. Teaching instruments is valid after revision based on the assessment of experts and peers. Assessment results finally obtained an average value Syllabus validity 3,36; Lesson Plan 3,24; and validity module is 3,23 (highest score 4) include a valid criterion, 2. Implementation of the stated learning class student achievement test instruments with an average of 70,33 better than the learning achievement of students in the control class with an average of 60.60. Based on the results of a valid and effective teaching instruments shows the development achieved.Keywords : Teaching Instruments, SMAR
Van der Waals and resonance interactions between accelerated atoms in vacuum and the Unruh effect
We discuss different physical effects related to the uniform acceleration of
atoms in vacuum, in the framework of quantum electrodynamics. We first
investigate the van der Waals/Casimir-Polder dispersion and resonance
interactions between two uniformly accelerated atoms in vacuum. We show that
the atomic acceleration significantly affects the van der Waals force, yielding
a different scaling of the interaction with the interatomic distance and an
explicit time dependence of the interaction energy. We argue how these results
could allow for an indirect detection of the Unruh effect through dispersion
interactions between atoms. We then consider the resonance interaction between
two accelerated atoms, prepared in a correlated Bell-type state, and
interacting with the electromagnetic field in the vacuum state, separating
vacuum fluctuations and radiation reaction contributions, both in the
free-space and in the presence of a perfectly reflecting plate. We show that
nonthermal effects of acceleration manifest in the resonance interaction,
yielding a change of the distance dependence of the resonance interaction
energy. This suggests that the equivalence between temperature and acceleration
does not apply to all radiative properties of accelerated atoms. To further
explore this aspect, we evaluate the resonance interaction between two atoms in
non inertial motion in the coaccelerated (Rindler) frame and show that in this
case the assumption of an Unruh temperature for the field is not required for a
complete equivalence of locally inertial and coaccelerated points of views.Comment: 8 pages, Proceedings of the Eighth International Workshop DICE 2016
Spacetime - Matter - Quantum Mechanic
Resistive relaxation in field-induced insulator-metal transition of a (LaPr)SrMnO bilayer manganite single crystal
We have investigated the resistive relaxation of a
(LaPr)SrMnO single crystal, in
order to examine the slow dynamics of the field-induced insulator to metal
transition of bilayered manganites. The temporal profiles observed in remanent
resistance follow a stretched exponential function accompanied by a slow
relaxation similar to that obtained in magnetization and magnetostriction data.
We demonstrate that the remanent relaxation in magnetotransport has a close
relationship with magnetic relaxation that can be understood in the framework
of an effective medium approximation by assuming that the first order parameter
is proportional to the second order one.Comment: 6 pages,5 figure
Halloysite Nanotubes: Smart Nanomaterials in Catalysis
The use of clay minerals as catalyst is renowned since ancient times. Among the different clays used for catalytic purposes, halloysite nanotubes (HNTs) represent valuable resources for industrial applications. This special tubular clay possesses high stability and biocompatibility, resistance against organic solvents, and most importantly be available in large amounts at a low cost. Therefore, HNTs can be efficiently used as catalysts themselves or supports for metal nanoparticles in several catalytic processes. This review reports a comprehensive overview of the relevant advances in the use of halloysite in catalysis, focusing the attention on the last five years
A multidisciplinary approach using LCCA and micro-simulation 10 model for the management of the urban pavements
The maintenance and the rehabilitation of the urban road pavements are not often based on
systematic program and scheduling but rather on emergency or on other not identified reasons.
Moreover the Life Cycle Cost Analysis (LCCA), the only peculiar procedure for the
management pavement, finds its own application for highway and motorway, even if it is
possible to search the best investment for the urban interstate and arterials.
By the light of the quantity of the involved resources, it seems necessary to define an operative
methodology for programming the maintenance and rehabilitation activities for the urban
pavement. The paper is oriented towards the development of a multidisciplinary approach to
make decision on management of urban pavement using the basic concepts of the LCCA and
micro-simulation model to define a scheme of work zone that minimizes the delay on the traffic
flow.
The best rehabilitation strategy should be characterized by the lowest users\u2019 cost that depends on
the time period of the work zone, which is conditioned by both own scheme and the provided
treatment, and on \u201csocial cost\u201d as increased travel time for queue generation .
Different scenarios for different work zone plans were developed and a micro-simulation model
was used to assess increased total travel time of a traffic flow within the maintenance area.
In this work an analysis by means of the above mentioned approach was carried out on real scenario in the city of Palermo in order to point out the several frames of the adopted
methodology
Using a physically-based model, tRIBS-Erosion, for investigating the effects of climate change in semi-arid headwater basins.
Soil erosion due to rainfall detachment and flow entrainment of soil particles is a physical process responsible
for a continuous evolution of landscapes. The rate and spatial distribution of this phenomenon depend on several
factors such as climate, hydrologic regime, geomorphic characteristics, and vegetation of a basin. Many studies
have demonstrated that climate-erosion linkage in particular influences basin sediment yield and landscape morphology.
Although soil erosion rates are expected to change in response to climate, these changes can be highly
non-linear and thus require mechanistic understanding of underlying causes. In this study, an integrated geomorphic
component of the physically-based, spatially distributed hydrological model, tRIBS, the TIN-based Real-time
Integrated Basin Simulator, is used to analyze the sensitivity of semi-arid headwater basins to climate change.
Downscaled outputs of global circulation models are used to inform a stochastic weather generator that produces
an ensemble of climate scenarios for an area in the Southwest U.S. The ensemble is used as input to the integrated
model that is applied to different headwater basins of the Walnut Gulch Experimental Watershed to understand
basin response to climate change in terms of runoff and sediment yield. Through a model application to multiple
catchments, a scaling relationship between specific sediment yield and drainage basin area is also addressed and
probabilistic inferences on future changes in catchment runoff and yield are drawn. Geomorphological differences
among catchments do not influence specific changes in runoff and sediment transport that are mostly determined by
precipitation changes. Despite a large uncertainty dictated by climate change projections and stochastic variability,
sediment transport is predicted to decrease despite a non-negligible possibility of larger runoff rates
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