► We study the pore structure and water permeability. ► We discuss the relationship between the permeability and pore structure parameters. ► A modified model is proposed to predict the water ...permeability.
This study correlates the pore structure and water permeability of paste made of alkali activated fly ash (AAF) with varying silica and alkali content, curing age and curing temperature. The pore structure of AAF paste was examined by mercury intrusion porosimetry (MIP) and environmental scanning electron microscopy (ESEM), and compared with the pore structure of Portland cement paste. The results reveal that the pore structure of AAF paste with high silica content significantly differs from that of cement paste, resulting in different water permeability. For equal reaction age, the permeability of AAF paste was higher than that of cement paste with w/c=0.4, an effect (that was) especially pronounced at later ages. However, a longer curing time at elevated temperature could significantly decreased the water permeability of AAF paste. MIP results show a consistent relationship between water permeability and total porosity, effective porosity and pore threshold diameter, respectively. Furthermore, a modified model incorporating all hereby experimentally derived parameters, is proposed to predict the water permeability of AAF.
This anthology is based on the interdisciplinary project ‘FindMyBike: legal and technological concepts for the transmission of time-based geodata on a criminological and administrative science ...basis’. In this project, technological concepts for the location of theft-prone objects were developed and applied in cooperation with the police to facilitate the prosecution of such crimes and the recovery of the stolen objects using the example of bicycle theft. Its highly scientific approach with intensive references to police practice and the inclusion of protection and criminal police expertise in theory and field tests generate results that form the basis for further research.
•Total porosity measurement for gas shales without using crushed rock is presented.•The method uses a modified saturation – immersion technique with deionized water.•Porosity values are reproducible ...within a low average absolute uncertainty.•Swelling in gas shales during saturation with deionized water is not significant.•Solvent extraction pretreatment can remove solid organic matter.
Over the past decade interest in shale properties has increased due to the commercial success of gas shale plays. Despite their commercial importance, porosity measurement from gas shale samples is still challenging due to their extremely low permeability and complex pore structure. This leads to a significant uncertainty in the economic assessment of these plays. The current energy industry standard technique for measuring porosity in gas shales is based on methodology developed by the Gas Research Institute (GRI) that involves crushing a rock and aggressive pretreatment. The objective of this study is to develop an alternative method of measuring total porosity in gas shales. A porosity measurement using a liquid saturation and immersion technique with deionized water was adopted and modified for such applications. The water immersion porosimetry (WIP) technique was used to measure total porosity of shale samples from an Eastern Europe Silurian gas shale play and the Haynesville Shale from East Texas, USA. The samples were characterized for whole rock quantitative mineral and elemental composition, along with cation exchange capacity (CEC) and organic matter. The results from the WIP measurements are compared with other standard techniques including the GRI method and mercury intrusion porosimetry (MIP). An assessment of the advantages, potential errors, pitfalls and reproducibility of this method are also presented.
The experimental results indicate that WIP provides (i) highly reproducible porosity, grain density, and bulk density measurements for gas shales, (ii) the average absolute experimental uncertainty is ±0.22 porosity unit (p.u.), compared to the reported uncertainty level of 0.5p.u. for GRI measurements, (iii) standard MIP techniques systematically underestimate the porosity and grain density compared to WIP, because mercury cannot access the entire pore structure in shales, and (iv) grain density values obtained by the GRI method in samples with high organic matter content are higher compared to WIP measurements, probably because of dissolution of solid organic matter during solvent extraction pretreatment.
Von der Corona-Pandemie und den zu ihrer Eingrenzung getroffenen Maßnahmen wird erwartet, dass sie sich auf die Kriminalitätsentwicklung auswirken. Erste empirische Studien zur registrierten ...Kriminalität vornehmlich aus dem angelsächsischen Raum führen teilweise zu widersprüchlichen Befunden, wobei zumindest für Diebstahls- und Einbruchsdelikte Rückgänge während des Zeitraums des Lockdowns festgestellt werden. Im Beitrag wird auf Basis einer im Mai und Juni 2020 im Kanton Zürich durchgeführten Befragung untersucht, wie sich die Viktimisierung mit verschiedenen Delikten entwickelt hat. Den Auswertungen liegen Angaben von 1 236 Personen zugrunde, die zufällig für die Befragung ausgewählt und Online befragt wurden. Die Ergebnisse belegen, dass Cyberkriminalität während des Lockdowns deutlich zugenommen hat. Anstiege zeigen sich auch für weitere Delikte (Sachbeschädigung, Diebstahl). Zurückgegangen ist der Fahrraddiebstahl. Für Wohnungseinbrüche und Körperverletzungen ergeben sich keine Veränderungen während des Lockdowns, für den Bereich der häuslichen Gewalt widersprüchliche Befunde.
Consumers execute routine last mile logistics in most brick-and-mortar supply chains. The online version of last mile logistics varies greatly, but still suffers from substantial challenges - one of ...these being theft, specifically porch piracy. In fact, each day more than 1.7 Million packages are stolen or go missing each day in the United States. In this paper, we look at a consumer's decision, to buy or not to buy a drop box for online package delivery. We view this decision as an act of co-creation, something routine in both online and traditional retailing, the consumer co-creation of the supply chain. The purpose of this research is to examine the feasibility of using drop boxes, an alternative delivery system, to reduce retailer's financial and reputation costs and increase consumer confidence in direct ordering. We determine that such alternative infrastructures signal a potential increase in revenues for online retailers. We also show that consumers are willing to pay for such drop boxes even as they co-create a variety of supply chains.
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•Detecting illegal energy consumption in smart grid.•Developing a mathematical model based on Levenberg-Marquardt to identify non-technical loss.•Solving the electricity theft problem ...using customer energy consumption pattern analysis.•Classifying electricity companies' customers using probabilistic neural network.
Detection of illegal consumers is an extremely challenging problem in smart grids as well as traditional environments. In a smart grid environment, electrical energy illegal customers can be divided into two types; (1) if the customer consumes all of its required energy in a portion of day illegally, (2) if the customer consumes a portion of its required energy illegally. Many methods about illegal consumption or electricity theft detection have been proposed but they are able to detect only one type of illegal consumptions. In this paper, a combined method is proposed to detect both two types of illegal consumptions. Customer energy consumption pattern classification method based on probabilistic neural network and mathematical model based on Levenberg-Marquardt method are used to detect the first and second type of illegal consumption, respectively. Moreover, the impact of Distributed Generation (DG) sources on illegal consumption of electricity is analyzed and proposed detection algorithm is modified to compensate it. Experimental results are presented to show the effectiveness of this method in detection of both two types of illegal consumption.
•The macromolecular order of coal was characterized by Raman micro-spectroscopy.•The pore types and nano-structure of coal was determined by Atomic force microscopy.•Quantitative results provide ...useful information for the utilization of high-rank coal.
Magmatic intrusion into coal-bearing sequences can significantly affect the rank of the intruded coal and change the macromolecular and pore structures. Here, we use Raman microscope and Atomic force microscope (AFM) to obtain quantitative information on these transformations. Six coal samples of different ranks taken from a magmatic intrusion zone of Huainan Coalfield, China, were studied. The Raman spectra were fitted with a combination of 8 Lorentzian bands and 1 Gaussian band. We found that the macromolecular structures in coals of different ranks have significant relationships with Raman spectral parameters, particularly the band area ratios (ID1/IG, ID2/IG, ID3/IG, ID4/IG and IG/IAll). With the increase of coal rank, ID1/IG, ID2/IG, ID3/IG and ID4/IG show trends of decreasing intensity, suggesting an enhanced orientation of aromatic hydrocarbons. Observations by Atomic force microscopy indicate that the pore parameters (e.g. amount, size, shape) are quite different for different ranks of coals. The pore size of low-rank bituminous coal is much larger than high-rank anthracite and pore abundance is higher in the former. In addition, there is also good correspondence between the surface topography of coal grains and coal rank.
The evidence is compelling that extended use and production of energy are globally responsible for the serious deterioration of physical environment and climate change. The further penetration of ...renewable energy sources (RES) emerges as a crucial factor contributing to the mitigation of global warming. Within this framework wind energy is expected to have a leading role for Greece's compliance with the EU environmental targets of 2020. However, the installation of wind parks in specific regions with high wind potential is seriously constrained by the reaction of local communities. Using a survey the present research dissects public acceptance for existing and proposed wind farms in the region of Southern Evia, Greece. Results indicate an overall support for wind energy and confirm the growing inconvenience with NIMBYism, especially in areas with existing wind parks in operation, as a theoretical framework explaining resistance to planned wind energy investments. By contrasting self-reported ex ante- and ex post-perceptions of impacts and benefits we highlight the role of experience in community acceptance of wind energy installations. Our statistical models prescribe the profile of those most probably in favour of existing installations, new installations in other parts of Evia or new installations elsewhere in Greece. Finally, we introduce the ‘Not-In-My-Front-Yard’ (NIMFY) syndrome suggesting that the impact of visibility on public acceptance is far from being a simple concept as it is linked to both a physical landscape context and socio-economic parameters.
•We model community acceptance for existing and planned wind farms in Greece.•We confirm a generally positive attitude towards wind farms in Greece.•We construct statistical models of preference profiles on three different scales.•NIMBYism is linked to visual contact and proximity.•NIMFYism is proposed as an explanation of the role of proximity and visual intrusion.
In order to develop high performance poly(dimethylsiloxane)-polyacrylonitrile (PDMS/PAN) hollow fiber composite membranes for the separation of CO2/N2 and O2/N2 gas pairs, we have investigated: (1) ...the viscosity of PDMS solutions as a function of curing conditions; (2) pore size and pore size distribution of the PAN substrates as a function of spinning conditions and post-treatments and (3) the effects of pre-wetting agents, substrate morphology and PDMS concentration on the gas performance of the selective layer. Based on their complicated relationship, fundamental science and engineering have been elucidated to fabricate PDMS/PAN hollow fiber composite membranes with CO2, N2 and O2 permeances of 3700, 370 and 860GPU and selectivities of 10 and 2.2 for CO2/N2 and O2/N2 gas pairs at 25°C and 2atm, respectively. This O2/N2 separation performance is comparable with the best ever reported results for O2 enrichment. The PAN hollow fibers were prepared by a dry-jet wet spinning process and subsequently coated with PDMS by dip-coating. To increase gas permeance, experimental results show that, in addition to keeping substrate pores open, partially crosslinking PDMS and pre-wetting the PAN substrates by Fluorinert 72 (FC-72) or deionized water before dip coating in order to prevent intrusion are important. This study may provide insights and guidelines to fabricate highly permeable membranes in the industry for O2 enrichment, flue gas separation and CO2 capture.
PAN hollow fiber with an ultra-thin PDMS dense layer for CO2/N2 and O2/N2 separation. Display omitted
► PAN/PDMS composite hollow fiber membranes are prepared. ► Structures of PAN membrane substrates are studied. ► Using preweting agents and partially crosslinking PDMS can improve separtion performance. ► Excellent performance with O2 permeance of 860GPU and O2/N2 selectivity of 2.
