Heterojunction solar cell calculations

Solar cell efficiencies computed for semiconductor heterojunction cell

Ruling out the impact of defects on the below band gap photoconductivity of Ti supersaturated Si

In this study, we present a structural and optoelectronic characterization of high dose Ti implanted Si subsequently pulsed-laser melted (Ti supersaturated Si). Time-of-flight secondary ion mass spectrometry analysis reveals that the theoretical Mott limit has been surpassed after the laser process and transmission electron microscopy images show a good lattice reconstruction. Optical characterization shows strong sub-band gap absorption related to the high Ti concentration. Photoconductivity measurements show that Ti supersaturated Si presents spectral response orders of magnitude higher than unimplanted Si at energies below the band gap. We conclude that the observed below band gap photoconductivity cannot be attributed to structural defects produced by the fabrication processes and suggest that both absorption coefficient of the new material and lifetime of photoexcited carriers have been enhanced due to the presence of a high Ti concentration. This remarkable result proves that Ti supersaturated Si is a promising material for both infrared detectors and high efficiency photovoltaic devices

Modelling Discharge Rates and Ground Settlement Induced by Tunnel Excavation

Interception of aquifers by tunnel excavation results in water inflow and leads to drawdown of the water table which may induce ground settlement. In this work, analytical and numerical models are presented which specifically address these groundwater related processes in tunnel excavation. These developed models are compared and their performance as predictive tools is evaluated. Firstly, the water inflow in deep tunnels is treated. It is shown that introducing a reduction factor accounting for the effect of effective stress on hydrodynamic parameters avoids overestimation. This effect can be considered in numerical models using effective stress-dependent parameters. Then, quantification of ground settlement is addressed by a transient analytical solution. These solutions are then successfully applied to the data obtained during the excavation of the La Praz exploratory tunnel in the Western Alps (France), validating their usefulness as predictive tools

Test-beam and laboratory characterisation of the TORCH prototype detector

The TORCH time-of-flight (TOF) detector is being developed to provide particle identification up to a momentum of 10 GeV/c over a flight distance of 10 m. It has a DIRC-like construction with View the MathML source10mm thick synthetic amorphous fused-silica plates as a Cherenkov radiator. Photons propagate by total internal reflection to the plate periphery where they are focused onto an array of customised position-sensitive micro-channel plate (MCP) detectors. The goal is to achieve a 15 ps time-of-flight resolution per incident particle by combining arrival times from multiple photons. The MCPs have pixels of effective size 0.4 mm×6.6 mm2 in the vertical and horizontal directions, respectively, by incorporating a novel charge-sharing technique to improve the spatial resolution to better than the pitch of the readout anodes. Prototype photon detectors and readout electronics have been tested and calibrated in the laboratory. Preliminary results from testbeam measurements of a prototype TORCH detector are also presented

Prevalence and Socio-behavioral Influence of Early Childhood Caries, ECC, and Feeding Habits among 6-36 Months Old Children in Uganda and Tanzania.

Early childhood caries (ECC) is a serious problem that has remained unexplored in sub-Saharan Africa. This study aimed to identify possible socio-behavioral correlates of ECC focusing 6-36 months old children and their caretakers.\ud Cross sectional studies were conducted in a high fluoride rural area, Manyara, Tanzania and a low fluoride urban area, Kampala, Uganda. Totals of 1221 and 816 child - caretaker pairs attending health care facilities for growth monitoring were recruited in Manyara and Kampala, respectively. All caretakers completed face to face interviews at the health care facility. Children underwent oral clinical examination whereby ECC and Enamel hypoplasia were recorded using the dmft (WHO 1997) and the DDE index (FDI 1992). The prevalence of ECC was 3.7% in Manyara and 17.6% in Kampala. According to multiple logistic regression analyses, received oral health information from health worker was the strongest determinant of ECC in Manyara, adjusted OR 0.3, 95% CI 0.09 - 0.93. In Kampala, visible plaque, high sugar intake and presence of enamel hypoplasia associated with ECC, adjusted ORs 2.8 (95% CI 1.61- 4.95), 3.0 (95% CI 1.39 - 6.34) and 2.3 (95% CI 1.36 - 3.95). Oral health education aimed at caretakers of 6-36 months, including health care workers' information regarding the detrimental consequences for oral health of frequent sugar consumption and poor oral hygiene is important for prevention of ECC in Tanzania and Uganda

New H-mode regimes with small ELMs and high thermal confinement in the Joint European Torus

New H-mode regimes with high confinement, low core impurity accumulation, and small edge-localized mode perturbations have been obtained in magnetically confined plasmas at the Joint European Torus tokamak. Such regimes are achieved by means of optimized particle fueling conditions at high input power, current, and magnetic field, which lead to a self-organized state with a strong increase in rotation and ion temperature and a decrease in the edge density. An interplay between core and edge plasma regions leads to reduced turbulence levels and outward impurity convection. These results pave the way to an attractive alternative to the standard plasmas considered for fusion energy generation in a tokamak with a metallic wall environment such as the ones expected in ITER.& nbsp;Published under an exclusive license by AIP Publishing

Shattered pellet injection experiments at JET in support of the ITER disruption mitigation system design

A series of experiments have been executed at JET to assess the efficacy of the newly installed shattered pellet injection (SPI) system in mitigating the effects of disruptions. Issues, important for the ITER disruption mitigation system, such as thermal load mitigation, avoidance of runaway electron (RE) formation, radiation asymmetries during thermal quench mitigation, electromagnetic load control and RE energy dissipation have been addressed over a large parameter range. The efficiency of the mitigation has been examined for the various SPI injection strategies. The paper summarises the results from these JET SPI experiments and discusses their implications for the ITER disruption mitigation scheme