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11.
Fourier transform infrared spectroscopy was used to investigate PA6/clay nanocomposites (PA6CN) with various cooling histories from the melt, including rapid cooling (water-quenched), middle-rate cooling (air-cooling) and slow cooling (mold-cooling). In contrast to pure PA6 dominated by the α-phase, the addition of clay silicate layers favor the formation of the γ-crystalline phase in PA6CN.We focus on the reason why silicate layers favor the formation of γ-phase in PA6. Vaia et al. suggested that the addition of clay layers forces the amide groups of PA6 out of the plane formed by the chains. This results in conformational changes of the chains, which limits the formation of H-bonded sheets so that the γ-phase is favored. If this assumption is correct, PA6CN is expected to show some differences as compared with PA6 with respect to hydrogen bonding.The silicate layers were indeed found to weaken the hydrogen bonding both in the α- and γ-phases. This was also confirmed by X-ray diffraction studies. The γ-phase is most likely concentrated in regions close to the silicate layers, whereas the α-phase is favored in the bulk matrix. 相似文献
12.
Jianzhong Qi Rui Zhang Yanqiu Wang Andy Yuan Xue Ge Yu Lars Kulik 《World Wide Web》2014,17(6):1261-1293
We propose and study a new type of location optimization problem, the min-dist location selection problem: given a set of clients and a set of existing facilities, we select a location from a given set of potential locations for establishing a new facility, so that the average distance between a client and her nearest facility is minimized. The problem has a wide range of applications in urban development simulation, massively multiplayer online games, and decision support systems. We also investigate a variant of the problem, where we consider replacing (instead of adding) a facility while achieving the same optimization goal. We call this variant the min-dist facility replacement problem. We explore two common approaches to location optimization problems and present methods based on those approaches for solving the min-dist location selection problem. However, those methods either need to maintain an extra index or fall short in efficiency. To address their drawbacks, we propose a novel method (named MND), which has very close performance to the fastest method but does not need an extra index. We then utilize the key idea behind MND to approach the min-dist facility replacement problem, which results in two algorithms names MSND and RID. We provide a detailed comparative cost analysis and conduct extensive experiments on the various algorithms. The results show that MND and RID outperform their competitors by orders of magnitude. 相似文献
13.
Lars H. Wiedermann 《Journal of the American Oil Chemists' Society》1968,45(9):A515-A560
The formulation and control of margarine oils and margarines is based on an understanding of the relation between various
physical measurements and the composition of the oils and margarines. Solid-to-liquid-fat ratios are determined by dilatometry
or by nuclear magnetic resonance spectroscopy. Oils are chosen for their crystal habit under conditions of processing and
finishing.
Some margarine test methods involve appearance, oral melting characteristics, oil-off, slump or collapse, get-away, penetration,
and spreadability. Many measurements are effective only when they describe conditions over a range of temperatures. These
include dilatometry and consistency determinations which require multipoint measurements.
Presented at the American Oil Chemists' Society Short Course on “Processing and Quality Control of Fats and Oils,” Aug. 29–Sept.
1, 1966, Michigan State University, East Lansing, Mich. 相似文献
14.
Afaf Kamal-Eldin Lars Åke Appelqvist 《Journal of the American Oil Chemists' Society》1994,71(2):149-156
Seeds from different collections of cultivatedSesamum indicum Linn and three related wild species [specifically,S. alatum Thonn.,S. radiatum Schum & Thonn. andS. angustifolium (Oliv.) Engl.] were studied for their oil contents and fatty acid composition of the total lipids. The oils from wild seeds
were characterized by higher percentages of unsaponifiables (4.9, 2.6 and 3.7%, respectively) compared toS. indicum (1.4–1.8%), mainly due to their high contents of lignans. Total sterols accounted forca. 40, 22, 20 and 16% of the unsaponifiables of the four species, respectively. The four species were different in the relative
percentages of the three sterol fractions (the desmethyl, monomethyl and dimethyl sterols) and in the percentage composition
of each fraction. Campesterol, stigmasterol, sitosterol and Δ5-avenasterol were the major desmethyl sterols, whereas obtusifoliol, gramisterol, cycloeucalenol and citrostandienol were
the major monomethyl sterols, and α-amyrin, β-amyrin, cycloartenol and 24-methylene cycloartanol were the main dimethyl sterols
in all species. Differences were also observed among the four species in sterol patterns of the free sterols compared to the
sterol esters.Sesamum alatum contained less tocopherols (210–320 mg/kg oil), andS. radiatum andS. angustifolium contained more tocopherols (ca. 750 and 800 mg/kg oil, respectively) than didS. indicum (490–680 mg/kg oil). The four species were comparable in tocopherol composition, with γ-tocopherol representing 96–99% of
the total tocopherols. The four species varied widely in the identity and levels of the different lignans. The percentages
of these lignans in the oils ofS. indicum were sesamin (0.55%) and sesamolin (0.50%).Sesamum alatum showed 1.37% of 2-episesalatin and minor amounts of sesamin and sesamolin (0.01% each).Sesamum radiatum was rich in sesamin (2.40%) and contained minor amounts of sesamolin (0.02%), whereS. angustifolium was rich in sesangolin (3.15%) and also contained considerable amounts of sesamin (0.32%) and sesamolin (0.16%). 相似文献
15.
The effect of alumina pretreatment on the performance of alumina supported nickel catalysts was demonstrated in gas phase hydrogenation of toluene to methylcyclohexane. The state of the alumina was changed from pure to pure phase through various heat treatments in air. The catalysts were prepared from vapor phase by saturating the accessible binding sites on the pretreated alumina with the nickel precursor. The highest number of active sites for hydrogenation was observed for catalysts prepared on alumina having an incomplete phase transition and a / alumina phase ratio between 0.5 and 10. Results from temperature programmed desorption (TPD) studies revealed that a maximum in weakly chemisorbed hydrogen as well as in total amount of desorbed hydrogen was found for the same catalysts. By hydrogen chemisorption studies the total hydrogen uptake was found to correlate with the observed hydrogenation maximum. It is suggested that both the chemical and physical properties of the alumina influence the activity. An optimal metal-support interaction and structural defects on the alumina due to the phase transition can explain the observed maximum in the number of active sites and in hydrogen uptake. 相似文献
16.
17.
Color quantization is a common image processing technique where full color images are to be displayed using a limited palette of colors. The choice of a good palette is crucial as it directly determines the quality of the resulting image. Standard quantization approaches aim to minimize the mean squared error (MSE) between the original and the quantized image, which does not correspond well to how humans perceive the image differences. In this article, we introduce a color quantization algorithm that hybridizes an optimization scheme based with an image quality metric that mimics the human visual system. Rather than minimizing the MSE, its objective is to maximize the image fidelity as evaluated by S‐CIELAB, an image quality metric that has been shown to work well for various image processing tasks. In particular, we employ a variant of simulated annealing with the objective function describing the S‐CIELAB image quality of the quantized image compared with its original. Experimental results based on a set of standard images demonstrate the superiority of our approach in terms of achieved image quality. 相似文献
18.
Open to a Select Few? Matching Partners and Knowledge Content for Open Innovation Performance 下载免费PDF全文
Lars Bengtsson Nicolette Lakemond Valentina Lazzarotti Raffaella Manzini Luisa Pellegrini Fredrik Tell 《Creativity & Innovation Management》2015,24(1):72-86
The purpose of the paper is to illuminate the costs and benefits of crossing firm boundaries in inbound open innovation (OI) by determining the relationships among partner types, knowledge content and performance. The empirical part of the study is based on a survey of OI collaborations answered by R&D managers in 415 Italian, Finnish and Swedish firms. The results show that the depth of collaboration with different partners (academic/consultants, value chain partners, competitors and firms in other industries) is positively related to innovation performance, whereas the number of different partners and size have negative effects. The main result is that the knowledge content of the collaboration moderates the performance outcomes and the negative impact of having too many different kinds of partners. This illustrates how successful firms use selective collaboration strategies characterized by linking explorative and exploitative knowledge content to specific partners, to leverage the benefits and limit the costs of knowledge boundary crossing processes. 相似文献
19.
Zilu Liang Bernd Ploderer Wanyu Liu Yukiko Nagata James Bailey Lars Kulik Yuxuan Li 《Personal and Ubiquitous Computing》2016,20(6):985-1000
Getting enough quality sleep is a key part of a healthy lifestyle. Many people are tracking their sleep through mobile and wearable technology, together with contextual information that may influence sleep quality, like exercise, diet, and stress. However, there is limited support to help people make sense of this wealth of data, i.e., to explore the relationship between sleep data and contextual data. We strive to bridge this gap between sleep-tracking and sense-making through the design of SleepExplorer, a web-based tool that helps individuals understand sleep quality through multi-dimensional sleep structure and explore correlations between sleep data and contextual information. Based on a two-week field study with 12 participants, this paper offers a rich understanding on how technology can support sense-making on personal sleep data: SleepExplorer organizes a flux of sleep data into sleep structure, guides sleep-tracking activities, highlights connections between sleep and contributing factors, and supports individuals in taking actions. We discuss challenges and opportunities to inform the work of researchers and designers creating data-driven health and well-being applications. 相似文献
20.
Improved Quality Output through Computer‐Based Training: An Automotive Assembly Field Study 下载免费PDF全文
In this article, two field experiments, conducted in an automotive assembly plant, evaluate how computer‐based training of operational sequences and related quality information can support the assembly performance of the operators. The experiments were performed during the launch of a new vehicle. A comparison was made of learning progress and quality performance between a reference group of operators that only had regular training and a test group for which some of the regular training was replaced with individual computer‐based training. Both quantitative measures of the quality output and questionnaires and observations were used to evaluate the effects of computer‐based training. The results show a clear positive difference in learning progress and improvements in quality output for the test group compared with the reference group. This combined with positive attitudes expressed by the operators and their team leaders shows that this type of training is an effective way to train operators during launches of new vehicles in automotive production. 相似文献