The increase of luminosity of the LHC in 2011 also introduced an increase of computing requirements for data processing. This paper describes the data processing operations during 2011 prompt ...reconstruction as well as the end of year re-processing of the full data sample. It further gives an outlook to next evolutionary steps in the LHCb computing model for 2012 data processing and beyond.
Amongst link technologies, InfiniBand has gained wide acceptance in the framework of High Performance Computing (HPC), due to its high bandwidth and in particular to its low latency. Since InfiniBand ...is very flexible, supporting several kinds of messages, it is suitable, in principle, not only for HPC, but also for the data acquisition systems of High Energy Physics (HEP) Experiments. In order to check the InfiniBand capabilities in the framework of on-line systems of HEP Experiments, we performed measurements with point-to-point UDP data transfers over a 4-lane Double Data Rate InfiniBand connection, by means of the IPoIB (IP over InfiniBand) protocol stack, using the Host Channel Adapter cards mounted on a 8-lane PCI-Express bus of commodity PCs both as transmitters and receivers, thus measuring not only the capacity of the link itself, but also the effort required by the host CPUs, buses and Operating Systems. Using either the "Unreliable Datagram" or the "Reliable Connected" InfiniBand transfer modes, we measured the maximum achievable UDP data transfer throughput, the frame rate and the CPU loads of the sender/receiver processes and of the interrupt handlers as a function of the datagram size. Performance of InfiniBand in UDP point-to-point data transfer are then compared with that obtained with analogous tests per formed between the same PCs, using a 10-Gigabit Ethernet link.
Amongst link technologies, InfiniBand has gained wide acceptance in the framework of High Performance Com puting (HPC), due to its high bandwidth and in particular to its low latency. Since ...InfiniBand is very flexible, supporting several kinds of messages, it is suitable, in principle, not only for HPC, but also for the data acquisition systems of High Energy Physics (HEP) Experiments. In order to check the InfiniBand capabilities in the frame work of on-line systems of HEP Experiments, we performed measurements with point-to-point UDP data transfers over a 4-lane Double Data Rate InfiniBand connection, by means of the IPoIB (IP over InfiniBand) protocol stack, using the Host Channel Adaper cards mounted on a 8-lanes PCI-Express bus of commodity PCs both as transmitters and receivers, thus measuring not only the capacity of the link itself, but also the effort required by the host CPUs, buses and Operating Systems. Using either the "Unreliable Datagram" or the "Reliable Connected" InfiniBand transfer modes, we measured the maximum achievable UDP data transfer throughput, the frame rate and the CPU loads of the sender/receiver processes and of the interrupt handlers as a function of the datagram size.
In the prospect of employing 10 gigabit Ethernet as networking technology for online systems and offline data analysis centers of high energy physics experiments, we performed a series of ...measurements with point-to-point data transfers over 10 gigabit Ethernet links, using the network interface cards mounted on the PCI-Express bus of commodity PCs both as transmitters and receivers. In real operating conditions, the maximum achievable transfer rate through a network link is not only limited by the capacity of the link itself, but also by those of the memory and peripheral buses and by the ability of the CPUs and of the operating system to handle packet processing and interrupts raised by the network interface cards in due time. Besides the TCP and UDP maximum data transfer throughputs, we also measured the CPU loads of the sender/receiver processes and of the interrupt and soft-interrupt handlers as a function of the packet size, either using standard or ldquojumbordquo Ethernet frames. In addition, we also performed the same measurements by simultaneously reading data from fibre channel links and forwarding them through a 10 gigabit Ethernet link, hence emulating the behavior of a disk server in a storage area network exporting data to client machines via 10 gigabit Ethernet.
The objective of this first workshop on Multiple Partonic Interactions (MPI) at the LHC is to raise the profile of MPI studies, summarizing the legacy from the older phenomenology at hadronic ...colliders and favouring further specific contacts between the theory and experimental communities. The MPI are experiencing a growing popularity and are currently widely invoked to account for observations that would not be explained otherwise: the activity of the Underlying Event, the cross sections for multiple heavy flavour production, the survival probability of large rapidity gaps in hard diffraction, etc. At the same time, the implementation of the MPI effects in the Monte Carlo models is quickly proceeding through an increasing level of sophistication and complexity that in perspective achieves deep general implications for the LHC physics. The ultimate ambition of this workshop is to promote the MPI as unification concept between seemingly heterogeneous research lines and to profit of the complete experimental picture in order to constrain their implementation in the models, evaluating the spin offs on the LHC physics program.
Mathematical modeling and estimation of moisture transport properties in drying of acai biomass were done in this work. The first approach consisted of applying the diffusive model for three ...different boundary conditions at the particle's surface and the effective diffusivity considered a constant or variable parameter. It was found that the model's accuracy depended on the drying level and the boundary conditions for the effective diffusivity assumed as a constant parameter. Accordingly, the results from the Arrhenius relationship depended on the predictions of the different approaches of the diffusive model, giving different values of the activation energy for the same experimental condition. The effective diffusivity ranged from 9 × 10−11 to 7 × 10−10 m2 s−1 and the activation energy from 38 to 55 kJ mol−1, indicating a high resistance to moisture evaporation. The predictions were not improved when considering the effective diffusivity as a moisture-dependent parameter, possibly due to the simplifications used for calculations. The two-compartment concept consisted of a set of differential equations that gave the best concordance with experimental data. The kinetics parameters ranged from 0.2 to 17 h−1 and presented a well-defined variation with the operating conditions, encouraging its use in drying optimization for efficient conversion processes.
Acai berry residues have great potential for sustainable thermochemical conversion processes. Many of these systems, as well as drying technologies, use the fluidized bed technology, which requires ...the characterization of the minimum fluidization velocity. The experimental work consisted of obtaining pressure drop curves for different bed heights, inlet air temperature, and particles roughness. The theoretical and data simulation approaches encompassed the minimum fluidization velocity prediction by correlations found in literature and neural networks, respectively. The minimum fluidization velocities were determined in the range 0.67–1.56 m/s. The minimum fluidization velocity decreased exponentially with increasing air temperature in the range 50–80 °C, but increased with the increase of the bed height in the range 1.5–4.5 cm. This effect was only observed for particles with fibers, indicating a strong presence of interparticle cohesive forces. Correlations proposed by the literature were not adequate to predict the minimum conditions for fluidization since they are very specific for biomass type and fluidization conditions. Even performing parameter estimation from experimental data, it was observed a strong dependence on the particles properties and bed porosity at minimum conditions. The neural network developed in this work presented good accuracy in predicting the experimental results, and it can be considered a potential viable alternative to estimate the minimum fluidization velocity for different process conditions.
Sorghum Sorghum bicolor (L.) Moench has attracted much attention due to its promising approach for ethanol production. One main issue of industrial-scale sorghum processing is drying, which is a ...highly energy-cost operation. On the other hand, researchers have been suggesting potentials for energy savings by analyzing simultaneous heat and mass transfer phenomena by mathematical modeling. The current study aims to perform mathematical modeling of the drying process of sorghum grains considering the coupling between heat and mass transfer and analyze its energy performance. A mathematical model was developed consisting of two differential equations encompassing a transient macroscopic energy equation and a differential form of the analytical solution of the diffusion model. The model parameters were estimated from experiments conducted in a laboratory-scale fixed bed dryer under air temperatures ranging from 40 to 75 °C and air velocity of 1.8 m s−1. It has shown that moisture diffusion is the limiting transport mechanism due to the approach to the isothermal drying condition, leading to a good correlation between predicted and observed data. The estimated value of activation energy was 14.32 kJ mol−1, which is in the range for grains and seeds. Instantaneous values of the specific energy consumption decreased exponentially over time, and the calculated mean values varied from a minimum of 7358.5 kJ kg−1 to a maximum of 8927.1 kJ kg−1 from 40 to 75 °C. The findings will be used in future optimization studies of sorghum drying to balance process costs with system energy consumption.
•Experimental analysis of convective air-drying of sorghum grains.•Mathematical modeling considering analytical solution of the diffusive model.•Mathematical modeling of the heat and mass transfer.•Analysis of the coupling between the heat and mass transfer.•Determination of instantaneous indices of specific energy consumption.
Solid waste from acai berry (Euterpe oleracea Mart.) processing plants has gained attraction as biomass with great source of thermal energy. To increase the efficiency of thermochemical conversion ...process and improve its economic and environmental benefits, this bio-waste has to be submitted to drying, which is seen as a highly energy-intensive process. In this work, the coupling between heat and mass transfer established in convective drying of a spherical-shape biomass was investigated in order to obtain further information regarding to the isothermal approach. The experimental work consisted of the determination of temperature and moisture content of acai berry solid waste as function of the time at particle-level in a tunnel dryer. Experimental data was treated according to analytical solutions from heat and mass transfer diffusion theories, which provided the estimation of useful transport parameters to allow discussions of heat or mass transfer limiting and the approach to the isothermal condition. To facilitate this analysis, it was proposed a parameter called dimensionless penetration time. The experimental results showed that the temperature of the solid rapidly reached a stationary value closed to that for the gas, while the equilibrium moisture content took a longer time to be attained. In accordance to these findings, it was shown that heat and mass transfer phenomena are not strongly coupled for the reason that the dimensionless penetration time was much less than unity, indicating that the drying process is limited by moisture diffusion. Analysis of heat and mass transfer efficiencies was reported to strengthen such results.
•Experimental convective drying of a spherical-shape biomass.•Theoretical analysis by means of diffusive models of heat and mass transfer.•Analysis of the isothermal approach.•Investigation of the coupling between heat and mass transfer.•Determination of heat and mass transfer efficiencies.
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•Comparison of the drying kinetics in fixed, fluidized and vibro-fluidized bed.•Determination of the most effective drying method in terms of the energy efficiency.•Artificial neural ...networks to simultaneously predicts patterns for different dryers.•Performance analysis of the neural network to predict patterns outside database.•Neural network limitations and advantages towards drying process optimization.
Drying of inorganic particulate compounds is recognized as an energy-intensive process. Due to this fact, optimization studies through modeling and simulation of experimental data play a critical role towards process economic benefits. The main drawback of some models from literature is their dependence on operating parameters and dryer type, which can be a key issue for data generalization. Artificial neural networks may provide the first step to solve this problem. This study analyses the feasibility of neural models to fit and estimate drying kinetics data, cumulative and instantaneous energy efficiency indices from fixed, fluidized and vibro-fluidized bed dryers at different operating conditions. The networks were trained considering different scenarios for both drying kinetics and energy analysis. It was shown that the neural model is consistent to estimate new patterns not addressed in the trainings for the case in which the database is regarded for a single type of dryer. Simultaneous training considering multiple datasets of each dryer resulted in predictions with poor accuracy, but considering the complex hydrodynamic conditions of the moving beds, there is room for improvement when efficient data is used. In this way, neural models can be considered an interesting tool to predict parameters also for energy analysis.
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