Risk Analysis for the Infrastructure of a Hydrogen Economy

Increasing scarcity of fossil fuels makes the deployment of hydrogen in combination with renewable energy sources or the utilization of electricity from full time operation of existing power stations an interesting alternative. A pre-requisite is, however, the safety of the required infrastructure is investigated and its design is evaluated with the associated risk to know, at least, the risks are not higher than that of existing supplies. Therefore, a risk analysis considering its most important objects such as storage tanks, filling stations, vehicles as well as heating and electricity supplies for residential buildings was carried out. The last is considered as representative of the entire infrastructure. The risk analysis is based on fault and event tree analyses, wherever required, and consequence calculations using the PHAST code. The procedure for evaluating the risk and corresponding results will be presented taking one of the objects as an example

Geotechnical Properties of Lateritic Soil Stabilized with Periwinkle Shell Ash in Road Construction

This paper investigated the geotechnical properties of lateritic soil stabilized with periwinkle shell ash in road construction. The natural lateritic soil sample was gotten from Federal University of Technology, Akure and stabilized with 0, 2,4, 6, 8 and 10% of the periwinkle shell ash and were subjected to tests such as natural moisture content, specific gravity, atterberg's limit, compaction, california bearing ratio and unconfined compressive strength. The result of the classification tests shows that the natural lateritic soil is poor for road construction. The engineering value of the soil sample was enhanced by the addition of periwinkle shell ash. The optimum percentage by weight of soil of periwinkle shell ash for improvement of the strength of the lateritic soil is 6%. The periwinkle shell ash enhanced the suitability of the soil sample for its use as subgrade and subbase

Studi Penghematan Energi Pada Unit Ketel Uap Di Pabrik Gula

This paper presents an energy saving study result conducted in a sugar factory located in the East Java of Indonesia. Formerly, the sugar factory was designed to fulfil their energy demand by using an abundance free energy sources, called “baggase”. However, a fossil fuel consumption (i.e. residue) increased sharply to supply boilers due to the baggase availability was not sufficient. It impacted to the increasing of operational costs. Therefore, an energy saving study for the factory had been an interesting subject. The study proposed to assess boilers performance in the factory to reduce residue consumption. A detail energy audit method was conducted to identify the actual energy consumption, energy losses, and energy saving potential. The study results showed that energy saving potential for the boilers was about 11%. The main energy saving measures was to increase boilers efficiency from 64% to 75%. The study report also included with repairing recommendation for the boilers as well as its techno-economic analysis

Peculiar long-range superexchange in Cu2A2O7 (A = P, As, V) as a key element of the microscopic magnetic model

A microscopic magnetic model for alpha-Cu2P2O7 is evaluated in a combined theoretical and experimental study. Despite a dominant intradimer coupling J1, sizable interdimer couplings enforce long-range magnetic ordering at T_N=27 K. The spin model for alpha-Cu2P2O7 is compared to the models of the isostructural beta-Cu2V2O7 and alpha-Cu2As2O7 systems. As a surprise, coupled dimers in alpha-Cu2P2O7 and alternating chains in alpha-Cu2As2O7 contrast with a honeycomb lattice in beta-Cu2V2O7. We find that the qualitative difference in the coupling regime of these isostructural compounds is governed by the nature of AO4 side groups: d-elements (A = V) hybridize with nearby O atoms forming a Cu-O-A-O-Cu superexchange path, while for p-elements (A = P, As) the superexchange is realized via O-O edges of the tetrahedron. Implications for a broad range of systems are discussed.Comment: 8 pages, 5 figures, 1 table; discussion extende

Physiological and biochemical responses to exercise and training in adolescent runners

This thesis aims to identify physiological and biochemical variables, comparing sex, training status, age and maturity in sub-elite, endurance trained adolescents. Maximal lactate steady state was investigated and the effects of endurance training programmes measured. The first study assessed the reliability of absolute running speed, V02, and HR that correspond to the fixed blood lactate reference values of 2.0 and 2.5 mmo1. L"1 and the lactate threshold (LT) and found these measures to be reliable after endurance-trained adolescent runners completed two identical incremental treadmill tests within a 7-10 d period The second study was designed to determine the relationship between physiological variables and endurance running performance in this age group. Track-based, running performance times were available for 18 boys and 14 girls for the 800 m, and 16 boys and 13 girls for the 1500 m. The participants were tested using a step-wise incremental treadmill test and a Wingate anaerobic power test (WAnT) on separate occasions. The results from this study found that for the 1500m, running speeds corresponding to the fixed [BLa ] were a useful measure for assessing performance in endurance trained boys and girls. Unlike previous studies, peak V02 was not a significant physiological predictor of 1500m performance in either boys or girls. For the 1500 m performance in girls the anaerobic measure was no longer significant once variations in size or age had been taken into consideration. Whereas V VO2 peak and running economy may prove to be of some value when considering the 800m for boys, the running speed corresponding to a [BLa ] of 2.5 mmol-L-1 was the only meaningful physiological predictor variable for girls once differences in age and body size had been accounted for. The third study had three main objectives: (1) to identify the exercise intensity that corresponds to the (MLaSS) in adolescent, endurance trained runners, (2) to examine possible between sex differences, and (3) to compare the MLaSS with commonly cited fixed blood lactate reference variables. The participants were first tested using a step-wise incremental treadmill test to establish the blood lactate profile and peak VO 2. The running speed and % peak VO 2 at the MLaSS were not significantly different to those corresponding to the fixed [BL& ] of 2.0 and 2.5 mmol-L-1 (P>0.05). The % HR max at 2.5 mmol-L-1 was also not different to that at the MLaSS, whereas at 2.0 mmol-L-1 it was slightly lower (P<0.05). The running speed, % peak VO 2, and % HR max at the fixed [BLa] of 4.0 mmol-L-1 were significantly higher than those at the MLaSS (P<0.05). In conclusion, it is clear that the MLaSS corresponded to the relatively high exercise intensity in this sample of athletes. It would appear that the running speed, % peak VO 2, and % HR max at the MLaSS lies somewhere between the fixed [BLa ] of 2.0 and 2.5 mmol"L-1. These results confirm earlier work that has suggested a fixed [BLa ] of 2.5 mmol-L-1 may be used with young people' to assess and monitor endurance running performance in place of the more commonly used 4.0 mmol-L-1 that has received so much attention in adult-based studies. The fourth study examined the effect of exercise training on endurance performance, blood lactate profile in relation to running speed (RV) and cardio respiratory function (peak V02) in adolescent runners. This study demonstrated that resting HR, LT and 1 Use of the expression young people is increasingly common since the publication of the text, Young People and Physical Activity by Armstrong and Weisman in 1997. It is used within this document to generically represent the 6 to 18 year age group. 11 RV, HR, V02 and peak V02 at LT were significantly influenced by endurance training. When running time, running velocity and run performance time pre and postintervention were included in the analysis, the intervention did not have a significant effect on peak VO2. When percentage body fat was included as a covariate, there was a positive association with pre and post-training for all groups. The conclusion from these data is that maturity and training both have an effect, especially at supra suggested training levels. The results of the four inter-linked studies support an age-related increase in endurance in aerobic and anaerobic performance and indicated significant differences between boys and girls. From a coaching viewpoint the results reveal that, from the age of 14 to 18 years, runners should be introduced to high intensity training and that changes to the format of middle distance running performance in adolescent competition are recommended