Moisture transport and dehydration in heated gypsum, an NMR study

Nuclear magnetic resonance (NMR) is used to non-destructively measure the moisture and dehydration profiles in gypsum during one sided heating to temperatures of 400 °C reflecting the conditions during fire. The temperature and moisture profiles are recorded simultaneously. The gypsum used in the experiments was extensively characterised using TGA, DSC, MIP, and NMR. The influence of the initial moisture content on the drying and dehydration processes was tested by varying the moisture content of the samples: capillary saturated, 50% RH, and 0% RH.By calibrating the NMR signal with moisture content we have shown that it is possible to not only measure free or absorbed water with NMR, but also measure the degree of hydration of the gypsum. Furthermore, by comparing the NMR signal decays it is possible to distinguish between these two water populations. The measured water profiles reveal that during one sided heating of a gypsum sample the dehydration inside is taking place in a two-step reaction. Furthermore, the profiles indicate that the vapour produce by the dehydration reactions condensates and thereby increases the local moisture content. The condensated water forms a so-called moisture peak behind the dehydration front.To our knowledge the measurements described in this article are the first quantitative in-situ evidence for the existence of two dehydration fronts in gypsum during one sided heating. Furthermore, the built up of a moisture peak in gypsum behind the dehydration front has not been reported in the literature to our knowledge. The NMR heating experiments presented in this paper can be used to evaluate and validate hygro-thermal models in the field of fire research on building materials.     

Temporal coordination and adaptation to rate change in music performance.

People often coordinate their actions with sequences that exhibit temporal variability and unfold at multiple periodicities. We compared oscillator- and timekeeper-based accounts of temporal coordination by examining musicians' coordination of rhythmic musical sequences with a metronome that gradually changed rate at the end of a musical phrase (Experiment 1) or at the beginning of a phrase (Experiment 2). The rhythms contained events that occurred at the same periodic rate as the metronome and at half the period. Rate change consisted of a linear increase or decrease in intervals between metronome onsets. Musicians coordinated their performances better with a metronome that decreased than increased in tempo (as predicted by an oscillator model), at both beginnings and ends of musical phrases. Model performance was tested with an oscillator period or timekeeper interval set to the same period as the metronome (1:1 coordination) or half the metronome period (2:1 coordination). Only the oscillator model was able to predict musicians' coordination at both periods. These findings suggest that coordination is based on internal neural oscillations that entrain to external sequences. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

钢筋锈蚀状态的检测与MCI阻锈技术的应用

介绍了如何正确判断混凝土结构中钢筋 (丝 )的锈蚀状态以及如何使用MCI阻锈剂 ,并通过某桥锈蚀的混凝土梁防锈治理后近 1年的电位及电流密度的变化 ,进一步验证了MCI阻锈剂的有效性     

Technology learning for renewable energy: Implications for South Africa's long-term mitigation scenarios

Technology learning can make a significant difference to renewable energy as a mitigation option in South Africa's electricity sector. This article considers scenarios implemented in a Markal energy model used for mitigation analysis. It outlines the empirical evidence that unit costs of renewable energy technologies decline, considers the theoretical background and how this can be implemented in modeling. Two scenarios are modelled, assuming 27% and 50% of renewable electricity by 2050, respectively. The results show a dramatic shift in the mitigation costs. In the less ambitious scenario, instead of imposing a cost of Rand 52/t CO₂-eq (at 10% discount rate), reduced costs due to technology learning turn renewables into negative cost option. Our results show that technology learning flips the costs, saving R143. At higher penetration rate, the incremental costs added beyond the base case decline from R92 per ton to R3. Including assumptions about technology learning turns renewable from a higher-cost mitigation option to one close to zero. We conclude that a future world in which global investment in renewables drives down unit costs makes it a much more cost-effective and sustainable mitigation option in South Africa.     

Anticipated affective consequences of physical activity adoption and maintenance.

Objective: The expected emotional consequences of future actions are thought to play an important role in health behavior change. This research examined whether anticipated affective consequences of success and failure vary across stages of physical activity change and differentially predict physical activity adoption as compared to maintenance. Design: Using a prospective design over a 3-month period, a community sample of 329 healthy, middle-aged adults were assessed at 2 time points. Main Outcome Measures: Anticipated positive and negative emotions, stage of behavior change (precontemplation [PC], contemplation [C], preparation [P], action [A], maintenance [M]), and level of physical activity. Results: At baseline, anticipated positive emotions were greater in C versus PC, whereas anticipated negative emotions were greater in M versus A and in M versus P. Higher anticipated positive but not negative emotions predicted physical activity adoption and maintenance after 3 months. Conclusion: Although the expected affective consequences of future success and failure differentiated among individuals in the early and later stages of physical activity change, respectively; only the anticipated affective consequences of success predicted future behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Unit Roots and Asymmetric Smooth Transitions

It has been found useful, as an alternative to a difference-stationary generating model, to consider the possibility of stationarity around a function that permits a smooth transition from one linear trend to another. Previous research has concentrated on functions that are symmetric around the point at which 50% of the transition is completed. Here we permit the possibility of asymmetry in the transition, allowing for example slow entry to and rapid exit from this evolutionary phase. It is shown through simulation and an interesting real data set that this can lead to the detection of further departures from difference stationarity.     

TL 9000标准改版的变化情况

对TL 9000标准要求部分3.0版与4.0版之间的变化情况进行了归纳,并对变化的部分进行了解释,既有助于企业正确使用新版标准,同时也有利于使用人员了解新标准的内容.     

Rethinking downstream regulation: California's opportunity to engage households in reducing greenhouse gases

With the passage of the Global Warming Solutions Act of 2006 (AB32), California has begun an ambitious journey to reduce in-state GHG emissions to 1990 levels by 2020. Under the direction of executive order S-20-06, a mandated Market Advisory Committee (MAC) charged with studying market-based mechanisms to reduce GHG emissions, including cap and trade systems, has recommended taking an “upstream” approach to GHG emissions regulation, arguing that upstream regulation will reduce administrative costs because there are fewer agents. In this paper, we argue that, the total costs to society of a GHG cap and trade scheme can be minimized though downstream regulation, rather than the widely proposed upstream approach. We propose a household carbon trading system with four major components: a state allocation to households, household-to-household trading, households to utility company credit transfers, and utility companies to government credit transfers. The proposed system can also be considered more equitable than carbon taxes and upstream cap and trade systems to control GHG emissions from residential energy use and is consistent with AB32.     

Constructing a literature from case studies: Promise and limitations of the method.

This article responds to "Coaching at the Top: Assisting A Chief Executive and His Team ' (M. M. Krajl, 2001 see record 2001-01213-005) by critiquing the article. It extends the discussion by focusing on the desired characteristics of a case study and how a professional literature can be derived from well constructed case studies. Applying these principles to Krajl's article, the author notes some issues concerning the intervention and preceding assessment, including the choice of the term coaching to describe complex and multifaceted interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The influence of unilateral acceleration on color‐gamut properties of a TFT‐LCD

Abstract— This letter describes experiments in which a TFT‐LCD was exposed to unilateral acceleration amplitudes of different temporal profiles and durations. The results show that the color gamut is extended by increasing the load amplitude. Following the loading, the color gamut recedes and gradually approaches the reference range.