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[en] Regimes in moist stratified flows over simply shaped 3D mountains have been studied in numerical simulations made with a mesoscale meteorological model. One of the aims that this work intends to examine is the possible existence of multiple solutions, searching for different solutions depending on the path followed by the system in the parameter space. Results from three different sets of experiments are discussed here. In the first set of simulations, the height of the mountain has been progressively changed in time. In the second group of experiments, the humidity of the air flowing over the obstacle has been increased in time by adding a source term to the equation of evolution of moisture. The case of advection of moist air towards an obstacle, initially embedded in dry air, has been studied as a third type of flow. A dependence on the past history of the flow seems to characterize some types of system evolution, leading to different flow regimes over the obstacle. The experiments indicate that this result is mainly a consequence of changes of state of water, associated with the presence of humidity in the atmosphere. These effects are emphasized in the case of an elliptical mountain, with its longer axis perpendicular to the main flow. In the three different sets of experiments presented here, evident differences with simulations where flow parameters are kept constant from the beginning persist in the flow regimes, also for periods of time much longer than the characteristic time of evolution towards stationary solutions
[en] The principle of 1-Wire bus protocol, the characteristics of digital temperature sensor DSISB20, humidity sensor DHT11 and the ultra low power mixed signal processor MSP430F149 are introduced, which combined with PC formed a precise collection system with 8 channel temperature and 1 channel humidity. (authors)
[en] The Wireless Sensor Network (WSN) is composed of a large number of sensor nodes with limited computation communication, and battery facilities. One of the common applications of this network is environment monitoring through sensing motion, measuring temperature, humidity and radiation. One of the basic activities in WSN is data gathering which represents a great challenge. Many routing protocols are proposed for that network to collect and aggregate the data. The most popular ones are hierarchy and data centric routing protocols. The main goal of this study is to identify the most preferable routing protocol, to be used in each mobility model. This paper studies the performance of LEACH (Low Energy Adaptive Clustering Hierarchy) from hierarchy routing protocol and direct diffusion from data centric routing protocol which is not clarified until now. Moreover, a comparison between LEACH and direct diffusion protocol using NS2 simulator will be made, and an analysis of these protocols will be conducted. The comparison includes packet delivery ratio, throughput, average energy ratio, average delay, network lifetime, and routing overhead. The performance is evaluated by varying the number of sensor nodes under three mobility models Reference Point Group Mobility Model (RPGM), Manhattan and random waypoint mobility model. Simulation results show that LEACH routing protocol has a good performance in RPGM and Manhattan than random waypoint mobility model. Direct diffusion has a good performance in random waypoint mobility model than in RPGM and Manhattan mobility model
[en] The contribution comprises analysis that is based on scientific work as a part of participation on the international research project carried out at the University of Prešov in Prešov and Vienna University of Technology entitled 'Detection and Management of Risk Processes in Building Insulation' and numbered SRDA SK-AT-0008-10. Statistical approach with correlations among humidity, time and temperature values in the space between the wall and building insulation uses the set of data obtained during the measurement series as testing using a new technology with equipment that does not influence the environment properties in the space. Therefore such real mapping can bring a real picture of possible condensation as a risk process in the building envelope.
[en] In the process of nuclear radiation measurement, often the results relied on measuring the temperature and humidity of the environment to compensate. The design of a low-cost simple temperature and humidity logger in the article, can achieve the measurements of temperature, humidity in the experimental nuclear environment. The system uses AT89 series low-cost MCU controller, domestic DHT11 temperature and humidity sensors, and RS485 protocol for remote data transfer and on-line monitoring of results. Experimental results show that the collector can achieve rapid multi-point measurements of temperature and humidity, the system is stable and reliable, is a low-cost solution, suitable for all kinds of nuclear measurement applications. (authors)
[en] Increasing numbers of galleries, museums and archives are including ink jet printed materials into their collections, and therefore displays. There is evidence that the instability of these prints is such that images can suffer deterioration in print quality or in extreme cases, a loss of information over an extended period of time. This is shorter than the period typically required for perceptible deterioration to occur in many other paper-based artworks. The image stability of prints is affected by a number of factors some of which have already been studied. However the role played by the ink solvent in the loss of image quality has yet to be explored. This paper will outline research being undertaken to investigate the effects of solvent content which may increase/promote the loss in image quality of the hard copy prints when stored or displayed under a range of temperature and humidity conditions.
[en] In order to effectively hold the measuring point surroundings condition record information in nuclear fallout measuring instrument inside, the measurement data has more practical meaning, also facilitate comprehensive analysis and processing. It will have high sensitivity, low interference, easy to install characteristics of temperature and humidity, wind speed sensor and wind-direction sensors, rainfall sensor embedded into to MSP430F169 as the core of the nuclear instruments, realizing the environmental parameters of the acquisition, and in each sensor is introduced based on the theory of, will of communication between the microcontroller and sensor method and software and hardware design to do a detailed explanation. Experiments prove, the text of the design method is feasible, instrument completely can achieve in nuclear detection applications in the field of requirements. (authors)
[en] Laboratory investigations on pulsed current spreading from spherical electrodes and evolution of electrical breakdown of silica sand with different water contents under a 15–20 kV voltage pulse were carried out. A sharp nonlinear decrease in the pulsed resistance of soil was observed when the current density exceeded a certain threshold value. Then ionization-overheating instability develops and leads to current contraction and plasma channel formation in the soil. The method for determination of the threshold electric field for ionization is proposed. Electrical discharge in wet sand was found to develop with a significant delay time for long discharge gaps similar to thermal breakdown. (paper)
[en] In this study, a parametric study was performed for the spraying technique used to fabricate polystyrene (PS) superhydrophobic surfaces. The spraying distance, the spraying time and the polymer concentration were selected as the parameters to be varied. Tetrahydrofuran (THF) was used for the solvent. First, a dissolved PS solution in THF was prepared. Then, the dissolved PS solution was sprayed onto the coverglass. The Nozzle size, working pressure, glove box temperature and humidity were fixed at 0.2 mm, 0.2 MPa, 23.15±0.83 .deg. C and 54.13±1.46%, respectively. After that, the surface morphology of the sprayed surface and water contact angle (WCA) were assessed by Scanning electron microscopy (SEM) and a contact angle meter. According to the spraying distance increased, the WCA was decreased in all three cases of the 1.5 vol% PS solution. However, the WCA was approximately 158 .deg. regardless of the spraying time or distance in all three cases of 6.0 vol% PS solution. The amount of PS deposited per unit area was shown to be the key parameter in determining the hydrophobicity, as expected. However, the PS concentration and the spraying distance affected the hydrophobicity regardless of the amount of PS deposited. Additionally, using least-squares method of the Origin 8.1 program fitting procedures for the WCA results, a water-contact-angle map of the PS-sprayed specimen was generated within the experimental parameters.
[en] Cirrus clouds are ubiquitous in the upper troposphere and still constitute one of the largest uncertainties in climate predictions. Our paper evaluates cloud-resolving model (CRM) and cloud system-resolving model (CSRM) simulations of a midlatitude cirrus case with comprehensive observations collected under the auspices of the Atmospheric Radiation Measurements (ARM) program and with spaceborne observations from the National Aeronautics and Space Administration A-train satellites. The CRM simulations are driven with periodic boundary conditions and ARM forcing data, whereas the CSRM simulations are driven by the ERA-Interim product. Vertical profiles of temperature, relative humidity, and wind speeds are reasonably well simulated by the CSRM and CRM, but there are remaining biases in the temperature, wind speeds, and relative humidity, which can be mitigated through nudging the model simulations toward the observed radiosonde profiles. Simulated vertical velocities are underestimated in all simulations except in the CRM simulations with grid spacings of 500 m or finer, which suggests that turbulent vertical air motions in cirrus clouds need to be parameterized in general circulation models and in CSRM simulations with horizontal grid spacings on the order of 1 km. The simulated ice water content and ice number concentrations agree with the observations in the CSRM but are underestimated in the CRM simulations. The underestimation of ice number concentrations is consistent with the overestimation of radar reflectivity in the CRM simulations and suggests that the model produces too many large ice particles especially toward the cloud base. Simulated cloud profiles are rather insensitive to perturbations in the initial conditions or the dimensionality of the model domain, but the treatment of the forcing data has a considerable effect on the outcome of the model simulations. Despite considerable progress in observations and microphysical parameterizations, simulating the microphysical, macrophysical, and radiative properties of cirrus remains challenging. Comparing model simulations with observations from multiple instruments and observational platforms is important for revealing model deficiencies and for providing rigorous benchmarks. But, there still is considerable need for reducing observational uncertainties and providing better observations especially for relative humidity and for the size distribution and chemical composition of aerosols in the upper troposphere.