Finding active factors from unreplicated fractional factorials utilizing the total time on test (TTT) technique

Much research has been devoted to improving the process of identifying active factors from designed experiments. Generally, the proposed methods rely on an estimate of the experimental error. Here we present a method based on the TTT (total time on test) plot, where the scaled TTT transform enables an evaluation of the contrasts independently of the experimental error. The method can be separated into two parts. The first part consists of a transformed TTT plot for a visual evaluation of data. The second part is more formal and utilizes the cumulative TTT statistic for testing the significance of contrasts. A simulation study shows the power of the method compared with competing methods. Five data sets are used to show that the conclusions drawn are consistent with those obtained using other suggested methods. Copyright © 1999 John Wiley & Sons, Ltd.     

Biogas production from grape pomace: Thermodynamic model of the process and dynamic model of the power generation system

In year 2010, the Province of San Juan – Argentina (South America) produced around 81 947 tons of grape pomace, which is a winery waste by-product. Wineries demand a great quantity of power during the three months that winemaking time lasts, which involve a high installed electric power. This power is used mainly for refrigerating the must during the fermentation. The control of temperature is crucial in winemaking as the low temperature preserves subtle fruit characters. An alternative for reducing the requirement of power from the utility electric grid is producing it locally, using the residuals generated by the own wineries. The technology for bioenergy conversion proposed to be implemented in this research for electricity generation is the anaerobic digestion of grape pomace. The aim of this research is to develop the thermodynamic equilibrium analysis of grape pomace anaerobic digestion based on the equilibrium constants for predicting the potential production of biogas and its composition. In addition, a dynamic model of a biogas-fuelled microturbine system for distributed generation applications is derived.     

Barrier properties of Al2O3 and alucone coatings and nanolaminates on flexible biopolymer films

Thin atomic layer deposited (ALD) Al₂O₃ coatings are efficient barriers against gases and vapors. Al₂O₃ coatings are, however, brittle and straining them generates defects that impair barrier properties. Flexibility of ALD-grown Al₂O₃ coatings on biopolymer substrates can be improved by separating thinner Al₂O₃ layers with inorganic-organic alucone layers. The number and size of defects were smaller for these nanolaminates compared to the thick Al₂O₃ films after straining, and hence straining deteriorated the oxygen barrier properties less when applied to the laminates than when applied to the Al₂O₃ coatings.     

Simulation of salinity effects on past, present, and future soil organic carbon stocks

Soil organic carbon (SOC) models are used to predict changes in SOC stocks and carbon dioxide (CO(2)) emissions from soils, and have been successfully validated for non-saline soils. However, SOC models have not been developed to simulate SOC turnover in saline soils. Due to the large extent of salt-affected areas in the world, it is important to correctly predict SOC dynamics in salt-affected soils. To close this knowledge gap, we modified the Rothamsted Carbon Model (RothC) to simulate SOC turnover in salt-affected soils, using data from non-salt-affected and salt-affected soils in two agricultural regions in India (120 soils) and in Australia (160 soils). Recently we developed a decomposition rate modifier based on an incubation study of a subset of these soils. In the present study, we introduce a new method to estimate the past losses of SOC due to salinity and show how salinity affects future SOC stocks on a regional scale. Because salinity decreases decomposition rates, simulations using the decomposition rate modifier for salinity suggest an accumulation of SOC. However, if the plant inputs are also adjusted to reflect reduced plant growth under saline conditions, the simulations show a significant loss of soil carbon in the past due to salinization, with a higher average loss of SOC in Australian soils (55 t C ha(-1)) than in Indian soils (31 t C ha(-1)). There was a significant negative correlation (p < 0.05) between SOC loss and osmotic potential. Simulations of future SOC stocks with the decomposition rate modifier and the plant input modifier indicate a greater decrease in SOC in saline than in non-saline soils under future climate. The simulations of past losses of SOC due to salinity were repeated using either measured charcoal-C or the inert organic matter predicted by the Falloon et al. equation to determine how much deviation from the Falloon et al. equation affects the amount of plant inputs generated by the model for the soils used in this study. Both sets of results suggest that saline soils have lost carbon and will continue to lose carbon under future climate. This demonstrates the importance of both reduced decomposition and reduced plant input in simulations of future changes in SOC stocks in saline soils.     

A cascode modulated class-E power amplifier for wireless communications

A cascode modulated CMOS class-E power amplifier (PA) is presented in this paper. It is shown that by applying a modulated signal to the gate of the cascode transistor the output power is modulated. The main advantage of the proposed technique is a high 35 dB output power dynamic range. The peak power added efficiency (PAE) is 35%. The concept of the cascode power control of class-E RF PA operating at 2.2 GHz with 18 dBm output power was implemented in a CMOS technology and the performance has been verified by measurements. The prototype CMOS PA is tested by single tone excitation and by enhanced data rates for GSM evolution (EDGE) modulated signal. Digital predistortion is used to linearize the transfer characteristic. The EDGE spectrum mask is met and the rms error vector magnitude (EVM) is less than 4° in the entire output power range.     

新式筛分设备布勒公司新一代提高灵活性、卫生性和实用性的“积木式组合“平筛

平筛的工作性能,对于制粉厂的经济效益,具有十分重要的影响.平筛是小麦制粉具有关键作用的设备,它们决定制粉厂的生产效率、产品的质量及其稳定性、纯净度和清洁度.     

Modified-atmosphere retail packaging of discovery apples

An experimental modified-atmosphere packaging system was used to compare the atmospheric compositions that developed within sealed packs made from a range of films of different permeability properties. The effects of these conditions were then related to the primary quality attributes, i.e. background skin colour and flesh firmness, and the sensory quality of Discovery apples. Concentrations of CO₂ and O₂ within packs were dependent on the permeability of the film and the holding temperature. In packs sealed with low density polyethylene films and held at 20°C, equilibrated atmospheres containing 3-5% CO₂ and 5-6% O₂ developed within 1-2 days. Softening and yellowing of fruit was markedly retarded. In packs sealed with some less permeable films, atmospheres containing 12-20% CO₂ and 0.9-4% O₂ developed within 1-2 days, resulting in retarded softening and yellowing of the fruit but also a high incidence of tainting. Possible commercial applications, benefits and limitations of modified-atmosphere packaging are discussed.     

Spatial analysis of diffusion tensor tractography statistics along the inferior fronto-occipital fasciculus with application in progressive supranuclear palsy

Background

The purpose of the study was to develop a method for analysis of diffusion parameters along white matter (WM) tracts, using spatial normalization based on anatomical landmarks, and to introduce the apparent area coefficient (AAC). The method’s applicability was tested in the inferior fronto-occipital fasciculus (IFO) in patients with progressive supranuclear palsy (PSP) and healthy controls (HCs).

Methods

A framework for analysis of diffusion parameters was developed. Spatial normalization of the tracts was performed using anatomical landmarks, to avoid deformations caused by cerebral atrophy. Initially, 38 HCs were used to optimize a threshold for the minimal size of regions that differ between groups. The fractional anisotropy, mean diffusivity, AAC, and the hemispheric asymmetry index (AI), were compared between 11 PSP patients and 15 HCs.

Results

The method was feasible for analysis of PSP patients and HCs. The AI showed that the observed hemispheric asymmetry of AAC was significantly larger in PSP patients compared with HCs in small regions of the IFO.

Conclusions

The method was successfully employed for analysis of diffusion parameters along the IFO in a patient group. This method can be potentially useful in studies of WM diseases, with or without cerebral atrophy.     

On the rate of growth and extent of the steady damage accumulation phase in repeated impact tests

In the paper, data of repeated impact tests performed on seven laminates of different lay-up and thickness are used to illustrate how the damage index (DI), a damage variable recently introduced by the authors to monitor the range of the penetration process in thick laminates, can be applied in case of repeated impact tests to get information on the rate of initial steady damage accumulation as well as on the onset of severe damage modes.Curves of the rate of growth of the DI in the steady phase (ΔDI/ΔN) vs. the normalised impact energy (ratio of the impact energy E_i and the laminate penetration threshold P_n) show no significant damage accumulation besides initial specimen indentation for impact energies below 0.2P_n. For intermediate levels of impact energy, repeated impact tests are characterised by an initial region of steady damage accumulation followed by an abrupt change in the rate of damage growth a few impacts before laminate perforation. For higher impact energies (E_i/P_n > 0.4–0.45), no phase of steady damage accumulation is present, suggesting that severe damage mechanisms take place from the very first impacts. Values of the DI at the end of the steady phase (DI_unsteady) are shown to be rather peculiar to each laminate regardless of the impact energy used in the tests and therefore may be used to get a first indication of the laminate performance to repeated impacts. The extent of the steady phase may also be used to compute the total energy absorbed by the laminate in the steady damage accumulation phase (E_aTOT__steady).