Experimental Validation of Multiphase Flow Models and Testing of Multiphase Flow Meters: A Critical Review of Flow Loops Worldwide

Around the world, research into multiphase flow is performed by scientists with hugely diverse backgrounds: physicists, mathematicians and engineers from mechanical, nuclear, chemical, civil, petroleum, environmental and aerospace disciplines. Multiphase flow models are required to investigate the co-current or counter-current flow of different fluid phases under a wide range of pressure and temperature conditions and in several different configurations. To compliment this theoretical effort, measurements at controlled experimental conditions are required to verify multiphase flow models and assess their range of applicability, which has given rise to a large number of multiphase flow loops around the world. These flow loops are also used intensively to test and validate multiphase flow meters, which are devices for the in-line measurement of multiphase flow streams without separation of the phases. However, there are numerous multiphase flow varieties due to differences in pressure and temperature, fluids, flow regimes, pipe geometry, inclination and diameter, so a flow loop cannot represent all possible situations. Even when experiments in a given flow loop are believed to be sufficiently exhaustive for a specific study area, the real conditions encountered in the field tend to be very different from those recreated in the research facility. This paper presents a critical review of multiphase flow loops around the world, highlighting the pros and cons of each facility with regard to reproducing and monitoring different multiphase flow situations. The authors suggest a way forward for new developments in this area

Experimental validation of multiphase flow models and testing of multiphase flow meters: A critical review of flow loops worldwide

Around the world, research into multiphase flow is performed by scientists with hugely diverse backgrounds: physicists, mathematicians and engineers from mechanical, nuclear, chemical, civil, petroleum, environmental and aerospace disciplines. Multiphase flow models are required to investigate the co-current or counter-current flow of different fluid phases under a wide range of pressure and temperature conditions and in several different configurations. To compliment this theoretical effort, measurements at controlled experimental conditions are required to verify multiphase flow models and assess their range of applicability, which has given rise to a large number of multiphase flow loops around the world. These flow loops are also used intensively to test and validate multiphase flow meters, which are devices for the in-line measurement of multiphase flow streams without separation of the phases. However, there are numerous multiphase flow varieties due to differences in pressure and temperature, fluids, flow regimes, pipe geometry, inclination and diameter, so a flow loop cannot represent all possible situations. Even when experiments in a given flow loop are believed to be sufficiently exhaustive for a specific study area, the real conditions encountered in the field tend to be very different from those recreated in the research facility. This paper presents a critical review of multiphase flow loops around the world, highlighting the pros and cons of each facility with regard to reproducing and monitoring different multiphase flow situations. The authors suggest a way forward for new developments in this area

KRAS early testing. Consensus initiative and cost-effectiveness evaluation for metastatic colorectal patients in an italian setting

KRAS testing is relevant for the choice of the most appropriate first-line therapy of metastatic colorectal cancer (CRC). Strategies for preventing unequal access to the test should be implemented, but their relevance in the practice is related to economic sustainability. The study adopted the Delphi technique to reach a consensus on several topics. Issues related to execution of KRAS testing were identified by an expert's board and proposed to 108 Italian oncologists and pathologists through two subsequent questionnaires. The emerging proposal was evaluated by decision analyses models employed by technology assessment agencies in order to assess cost-effectiveness. Alternative therapeutic strategies included most commonly used chemotherapy regimens alone or in combination with cetuximab or bevacizumab. The survey indicated that time interval for obtaining KRAS test should not exceed 15 days, 10 days being an optimal interval. To assure the access to proper treatment, a useful strategy should be to anticipate the test after radical resection in patients at high risk of relapse. Early KRAS testing in high risk CRC patients generates incremental cost-effectiveness ratios between 6,000 and 13,000 Euro per quality adjusted life year (QALY) gained. In extensive sensitivity analyses ICER's were always below 15,000 Euro per QALY gained, far within the threshold of 60,000 Euro/QALY gained accepted by regulatory institutions in Italy. In metastatic CRC a time interval higher than 15 days for result of KRAS testing limits access to therapeutic choices. Anticipating KRAS testing before the onset of metastatic disease in patients at high risk does not affect the sustainability and cost-effectiveness profile of cetuximab in first-line mCRC. Early KRAS testing may prevent this inequality in high-risk patients, whether they develop metastases, and is a cost-effective strategy. Based on these results, present joined recommendations of Italian societies of Oncology and Pathology should be updated including early KRAS testing

Verifying Policy Enforcers

Policy enforcers are sophisticated runtime components that can prevent failures by enforcing the correct behavior of the software. While a single enforcer can be easily designed focusing only on the behavior of the application that must be monitored, the effect of multiple enforcers that enforce different policies might be hard to predict. So far, mechanisms to resolve interferences between enforcers have been based on priority mechanisms and heuristics. Although these methods provide a mechanism to take decisions when multiple enforcers try to affect the execution at a same time, they do not guarantee the lack of interference on the global behavior of the system. In this paper we present a verification strategy that can be exploited to discover interferences between sets of enforcers and thus safely identify a-priori the enforcers that can co-exist at run-time. In our evaluation, we experimented our verification method with several policy enforcers for Android and discovered some incompatibilities.Comment: Oliviero Riganelli, Daniela Micucci, Leonardo Mariani, and Yli\`es Falcone. Verifying Policy Enforcers. Proceedings of 17th International Conference on Runtime Verification (RV), 2017. (to appear

Advanced thermoplastic resins, phase 1

Eight thermoplastic polyimide resin systems were evaluated as composite matrix materials. Two resins were selected for more extensive mechanical testing and both were versions of LaRC-TPI (Langley Research Center - Thermoplastic Polyimide). One resin was made with LaRC-TPI and contained 2 weight percent of a di(amic acid) dopant as a melt flow aid. The second system was a 1:1 slurry of semicrystalline LaRC-TPI powder in a polyimidesulfone resin diglyme solution. The LaRC-TPI powder melts during processing and increases the melt flow of the resin. Testing included dynamic mechanical analysis, tension and compression testing, and compression-after-impact testing. The test results demonstrated that the LaRC-TPI resins have very good properties compared to other thermoplastics, and that they are promising matrix materials for advanced composite structures

Neutrinoless double beta decay in SO(10) inspired seesaw models

By requiring the lower limit for the lightest right-handed neutrino mass, obtained in the baryogenesis from leptogenesis scenario, and a Dirac neutrino mass matrix similar to the up-quark mass matrix we predict small values for the $\nu_e$ mass and for the matrix element $m_{ee}$ responsible of the neutrinoless double beta decay, $m_{\nu_e}$ around $5\cdot10^{-3}$ eV and $m_{ee}$ smaller than $10^{-3}$ eV, respectively. The allowed range for the mass of the heaviest right-handed neutrino is centered around the value of the scale of B - L breaking in the SO(10) gauge theory with Pati-Salam intermediate symmetry.Comment: 9 pages, RevTex4. Revised, title change

Analysis of Energy Consumption Performance towards Optimal Radioplanning of Wireless Sensor Networks in Heterogeneous Indoor Environments

In this paper the impact of complex indoor environment in the deployment and energy consumption of a wireless sensor network infrastructure is analyzed. The variable nature of the radio channel is analyzed by means of deterministic in-house 3D ray launching simulation of an indoor scenario, in which wireless sensors, based on an in-house CyFi implementation, typically used for environmental monitoring, are located. Received signal power and current consumption measurement results of the in-house designed wireless motes have been obtained, stating that adequate consideration of the network topology and morphology lead to optimal performance and power consumption reduction. The use of radioplanning techniques therefore aid in the deployment of more energy efficient elements, optimizing the overall performance of the variety of deployed wireless systems within the indoor scenario

X-Ray Spectral Variability of Extreme BL Lac AGN H1426+428

Between 7 March 2002 and 15 June 2002, intensive X-ray observations were carried out on the extreme BL Lac object H1426+428 with instruments on board the Rossi X-ray Timing Explorer (RXTE). These instruments provide measurements of H1426+428 in the crucial energy range that characterizes the first peak of its spectral energy distribution. This peak, which is almost certainly due to synchrotron emission, has previously been inferred to be in excess of 100 keV. By taking frequent observations over a four-month campaign, which included $\sim$450 ksec of RXTE time, studies of flux and spectral variability on multiple timescales were performed, along with studies of spectral hysteresis. The 3-24 keV X-ray flux and spectra exhibited significant variability, implying variability in the location of the first peak of the spectral energy distribution. Hysteresis patterns were observed, and their characteristics have been discussed within the context of emission models.Comment: accepted for publication in Astrophysical Journa

Near-infrared spectroscopy study of tourniquet-induced forearm ischaemia in patients with coronary artery disease

Near-Infrared Spectroscopy (NIR) can be employed to monitor local changes in haemodynamics and oxygenation of human tissues. A preliminary study has been performed in order to evaluate the NIRS transmittance response to induced forearm ischaemia in patients with coronary artery disease (CAD). The population consists in 40 patients with cardiovascular risk factors and angiographically documented CAD, compared to a group of 13 normal subjects. By inflating and subsequently deflating a cuff placed around the patient arm, an ischaemia has been induced and released, and the patients have been observed until recovery of the basal conditions. A custom LAIRS spectrometer (IRIS) has been used to collect the backscattered light intensities from the patient forearm throughout the ischaemic and the recovery phase. The time dependence of the near-infrared transmittance on the control group is consistent with the available literature. On the contrary, the magnitude and dynamics of the NIRS signal on the CAD patients show deviations from the documented normal behavior, which can be tentatively attributed to abnormal vessel stiffness. These preliminary results, while validating the performance of the IRIS spectrometer, are strongly conducive towards the applicability of the NIRS technique to ischaemia analysis and to endothelial dysfunction characterization in CAD patients with cardiovascular risk factors.Publisher PD

Liquid loading in gas wells: experimental investigation of back pressure effects on the near-wellbore reservoir

A large-scale core-flooding experimental setup was designed and constructed to investigate the back pressure effects on transient flow through porous medium, and so mimic the physical process of liquid loading and reservoir response. Between initial and final steady-state flowing conditions, where inlet pressure was maintained at a constant level while initiating a transient pressure build up at the core sample end, an “U-shaped” temporal distribution of pore fluid pressure within the medium itself was observed, which is in direct contrast to the conventional reservoir pressure profile