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High Magnitude (high + magnitude)
Selected AbstractsFlooding and geomorphic impacts in a mountain torrent: Raise Beck, central Lake District, EnglandEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2002R. M. Johnson Abstract Raise Beck is a mountain torrent located in the central Lake District fells, northern England (drainage area of 1·27 km2). The torrent shows evidence of several major flood events, the most recent of which was in January 1995. This event caused a major channel avulsion at the fan apex diverting the main flood flow to the south, blocking the A591 trunk road and causing local flooding. The meteorological conditions associated with this event are described using local rainfall records and climatic data. Records show 164 mm of rainfall in the 24 hours preceding the flood. The peak flood discharge is reconstructed using palaeohydrological and rainfall,runoff methods, which provide discharge values of 27,74 m3 s,1, and 4,6 m3 s,1, respectively. The flood transported boulders with b-axes up to 1400 mm. These results raise some important general questions about flood estimation in steep mountain catchments. The geomorphological impact of the event is evaluated by comparing aerial photographs from before and after the flood, along with direct field observations. Over the historical timescale the impact and occurrence of flooding is investigated using lichenometry, long-term rainfall data, and documentary records. Two major historical floods events are identified in the middle of the nineteenth century. The deposits of the recent and historical flood events dominate the sedimentological evidence of flooding at Raise Beck, therefore the catchment is sensitive to high magnitude, low frequency events. Following the 1995 flood much of the lower catchment was channelized using rip-rap bank protection, re-establishing flow north towards Thirlmere. The likely success of this management strategy in containing future floods is considered, based on an analysis of channel capacities. It is concluded that the channelization scheme is only a short-term solution, which would fail to contain the discharge of an event equivalent to the January 1995 flood. Copyright © 2002 John Wiley & Sons, Ltd. [source] Effects of Brining Conditions on Weight Gain in Herring (Clupea harengus) FilletsJOURNAL OF FOOD SCIENCE, Issue 7 2005Sveinung Birkeland ABSTRACT: Salted herring is an important product category in many European countries. Reduced need for salt as a preserving agent and the increased emphasis on less salt in the human diet has changed the basis for the traditional processing of these products. This has led to significant changes in the processing conditions and in the characteristics of the salted products. In this perspective, the effects of different brine concentrations (10.0%, 16.5%, and 25.5%), brining temperatures (3.5 °C and 17.5 °C), the presence of skin or not on the fillets, and brining time (1, 2, 3, 4, and 7 d) were investigated on the weight gain (%) and final salt content (%) of herring (Clupea harengus). A significant (P < 0.001) higher weight gain of the fillets were observed at the lowest brining temperature (3.5 °C) compared with at the higher temperature (17.5 °C), independently of brine concentration and brining time. Increased brine concentration and skinning of the fillets caused the weight gain to significantly decrease (P < 0.001) and increase (P < 0.001), respectively. After 1 d of brining, the weight gain was in the range of 10% to 12% for both brining temperatures, and at the lowest temperature, the weight gain increased significantly (P < 0.001) as a function of brining time. At the higher temperature, no further significant increase in weight was observed from 1 to 7 d of brining. It is concluded that the weight gain in herring fillets brined according to the present commercial practice is significantly affected by temperature, brine concentration, brining time, and the presence or not of skin on the fillets and that the weight gain may be of high magnitude. [source] On the electrostatic equilibrium of granular flow in pneumatic conveying systemsAICHE JOURNAL, Issue 11 2006Jun Yao Abstract An analytical methodology involving the concept of "electrostatic equilibrium" is developed for granular flow in pneumatic conveying systems. The methodology can be used for estimation of the electrostatic field distribution at various sections of the system and explanation of the mechanisms involved for various electrostatic phenomena observed. For all cases conducted in the conveying system, there was a "charging time" required for the system to reach the state of "electrostatic equilibrium." Experiments conducted at different sections of the system showed that the time required increased in the order: horizontal pipe, vertical pipe, and pipe bend. Through a physical analysis, it is deduced that electrostatic equilibrium is related to the granules' behavior and local flow characteristics. In general, a longer time duration taken to reach equilibrium corresponds to a process with more complicated granular flow patterns. In the electrostatic equilibrium state, the field distribution shows the highest electrostatic field strength near the pipe wall, and this field strength degrades from the pipe wall to the pipe center. At various pipe sections, the highest strength occurs at the bend, in accord with observations that electric sparking first occurs at that location within the entire pneumatic conveying system. In the vertical pipe, granular distribution was measured using electrical capacitance tomography (ECT), and granular velocities were cross-referenced with those using particle image velocimetry (PIV). The electrostatic force at low air flow rates is found to be the primary cause for granules sticking to the pipe wall and results in the formation of the half-ring or ring structure. The state of electrostatic equilibrium is physically influenced by several elements in conveying systems. In a cyclic conveying system, a new pipe (or low humidity or no antistatic agent) tends to expedite the process to reach electrostatic equilibrium and attain high magnitude of electrostatic current at the state. In a non-cyclic horizontal conveying system, a thin film (pipe) is found to prolong the process duration to reach equilibrium, while the case with charged film (pipe) takes shorter duration to do so. © 2006 American Institute of Chemical Engineers AIChE J, 2006 [source] High-Energy Density Ceramic Composition in the System Pb(Zr,Ti)O3,Pb[(Zn,Ni)1/3Nb2/3]O3JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2006Rashed Adnan Islam This study reports a high-energy density piezoelectric polycrystalline ceramic composition in the system Pb(Zr1,xTix)O3,Pb[(Zn1,yNiy)1/3Nb2/3]O3 (PZT,PZNN). Two different Zr/Ti ratios in the PZT system were investigated: 52/48 corresponding to morphotropic phase boundary (MPB) and 56/44 corresponding to the tetragonal phase. The compositions investigated in this study are represented as: 0.9Pb(Zr0.52Ti0.48)O3,0.1Pb(Zn1/3Nb2/3)O3 [0.9PZT (52:48),0.1PZN]+y wt% MnCO3, where y varies from 0 to 0.9 wt% and 0.9Pb(Zr0.56Ti0.44)O3,0.1Pb[(Zn0.8Ni0.2)1/3Nb2/3]O3 [0.9PZT (56:44),0.1PZNN] +y mol% MnO2, where y varies from 1 to 3 mol%. A high-energy density material is characterized by the large magnitude of the product of the piezoelectric voltage constant (g) and the piezoelectric strain constant (d) given as (dg). The condition for obtaining large magnitude of dg was derived to be as |d|=,n, where , is the permittivity of the material and n is a material constant having a lower limit of 0.5. The d33.g33 value of the samples having composition 0.9 PZT (56:44),0.1 PZNN+2 mol% MnO2 (sintered in two steps at 1100°,1000°C) was found to be 18456.2 × 10,15 m2/N, which, to the knowledge of the authors, is the highest value reported for polycrystalline ceramics. This composition was also found to exhibit a high magnitude of g33 as 83.1 V·(m·N),1, corresponding to the magnitude of n as 1.126. [source] Tracing back seed and pollen flow within the crop,wild Beta vulgaris complex: genetic distinctiveness vs. hot spots of hybridization over a regional scaleMOLECULAR ECOLOGY, Issue 6 2004Frédérique Viard Abstract Hybrids between transgenic crops and wild relatives have been documented successfully in a wide range of cultivated species, having implications on conservation and biosafety management. Nonetheless, the magnitude and frequency of hybridization in the wild is still an open question, in particular when considering several populations at the landscape level. The Beta vulgaris complex provides an excellent biological model to tackle this issue. Weed beets contaminating sugar beet fields are expected to act as a relay between wild populations and crops and from crops-to-crops. In one major European sugar beet production area, nine wild populations and 12 weed populations were genetically characterized using cytoplasmic markers specific to the cultivated lines and nuclear microsatellite loci. A tremendous overall genetic differentiation between neighbouring wild and weed populations was depicted. However, genetic admixture analyses at the individual level revealed clear evidence for gene flow between wild and weed populations. In particular, one wild population displayed a high magnitude of nuclear genetic admixture, reinforced by direct seed flow as evidenced by cytoplasmic markers. Altogether, weed beets were shown to act as relay for gene flow between crops to wild populations and crops to crops by pollen and seeds at a landscape level. [source] Efficacy of selection in sexually breeding Artemia (Artemia franciscana, Kellogg, 1906)AQUACULTURE RESEARCH, Issue 13 2006Mangesh M Shirdhankar Abstract Bi-directional selection for smaller naupliar size (SNS) and bigger naupliar size (BNS) was practiced to develop two divergent lines. The efficacy of bi-directional mass selection in Artemia franciscana was evaluated by comparing the predicted genetic gains with the realized genetic gains. Two sets of predictions were made using two heritability estimates, e.g., the heritability estimate from full-sib analysis (h2) and the estimate from regression of offspring on mid parent (bop). Predictions with the full-sib heritabilities were of very high magnitude as compared with predictions with bop heritabilities. The predictions based on bop were more or less in agreement with realized genetic gain, while the predictions with heritability estimates based on full-sib analysis were much higher than the realized gains. Ratios of realized gain to predicted gain based on full-sib heritabilities were 0.2302 and 0.2152, respectively, for males and females of the SNS line, and 0.0471 and 0.2248, respectively, for males and females of the BNS line. Ratios of realized gain to predicted gain based on bop were 1.5348 and 0.6069 for males and females of the SNS line and 0.1028 and 0.9503 for males and females of the BNS line. Ratios of realized gain to predicted gain based on full-sib heritability were of low magnitude in all the cases as the heritability estimates based on full-sib analysis were inflated by non-additive genetic variance. The ratios of realized gain to predicted gain based on bop were high in both sexes of SNS and females of BNS, indicating high efficacy of selection as bop includes only additive genetic variance. However, it was of low magnitude in BNS males. Thus, the heritability estimates based on regression of offspring on mid parent (bop) are more reliable than that of heritability estimates based on full-sib analysis (h2) for predicting the selection response in Artemia. [source] | |||||||||||||