Search for: All records

Reforming of methane (CH4) is a process to produce syngas (CO/H2) and other value-added chemicals including oxygenates such as methanol (CH3OH). Atmospheric pressure plasmas have the potential to be more energy efficient than traditional reforming methods as value-added chemicals can be synthesized directly in the plasma without requiring an additional step. In this paper, we discuss the results from a computational investigation of the formation of oxygenates by CH4 oxidation in the presence of Ar, including CH3OH and CH2O, in a nanosecond pulsed dielectric barrier discharge. The plasma is formed in a microfluidic channel whose small dimensions are ideal for plasma formation at atmospheric pressure. The production and consumption mechanisms of dominant radicals and long-lived species are discussed in detail for the base case conditions of Ar/CH4/O2 = 50/25/25. CH3OH is produced primarily by CH3O reacting with CH3O and CH3O2 reacting with OH, while CH2O formation relies on reactions involving CH3O and CH3. The most abundant oxygenate formed is CO (produced by H abstraction from CHO). However, the greenhouse gas CO2 is also formed as a by-product. The effects of gas mixture are examined to maximize the CH3OH and CH2O densities while decreasing the CO2 density. Increasing the Ar percentage from 0% to 95% decreased the CH3OH and CH2O densities. At low Ar percentages, this is due to an increase in consumption of CH3OH and CH2O, while at high Ar percentages (>40% Ar), the production of CH3OH and CH2O is decreased. However, both CO and CO2 reached peak densities at 70%–90% Ar. Changing the CH4/O2 ratio while keeping 50% Ar in the discharge led to increased CH3OH and CH2O production, reaching peak densities at 35%–40% CH4. The CO and CO2 densities decreased beyond 20% CH4, indicating that a CH4 rich discharge is ideal for forming the desired oxygenates. 

Advances in hydraulic fracturing (aka “fracking”) technologies and horizontal drilling have enabled the extraction of previously unviable unconventional oil and gas resources. However, as global environmental concerns have become more prominent and unconventional oil and gas developments have moved ever closer to residential centers, public scrutiny of the industry and its methods and impacts of extraction have increased. Water impacts feature prominently among the contemporary societal concerns about fracking. These concerns include the large water requirements of the process itself, as well as concerns about the potential pollution of groundwater and the (underground) environment more broadly. Anthropologists have undertaken qualitative field research on unconventional gas developments in a variety of settings, largely among local communities in regions of extraction. The perspectives employed by anthropologists are commonly drawn from the broader social science literature, including the anthropology of water and natural resources, science and technology studies, studies of social movements, and studies which examine the energy‐society nexus. Based on the shortcomings of the published anthropological accounts, interdisciplinary research collaboration with hydrologists, engineers and economists, as well as a more fulsome engagement with the variety of hopes, fears and dreams of fracking and unconventional gas, is recommended.WIREs Water2018, 5:e1272. doi: 10.1002/wat2.1272 This article is categorized under:Engineering Water > Sustainable Engineering of WaterScience of Water > Water QualityHuman Water > Methods 

During the early Cold War, outer space became a politically contested space, and changes in its spatial perception were related to political and ideological controversies. The article highlights the specific relevance of Euclidean geometry in representations of outer space. Focusing on illustrations and expositions in both postwar German States, it argues that shifts within the spatial imagination and representation of space corresponded with the first satellite missions and condensed debates about the future of technology and the moral legacies of the Second World War. In October 1957, Sputnik I, the first artificial satellite to orbit the Earth and a Soviet construction, urged engineers, scientists, and illustrators to find new ways of depicting and communicating the spaces of outer space to the public and to each other. For decades, space fiction had implicitly stifled theories on the relativity of space and time by hinting at traditional motifs of conquest through machines. Early spaceflight, however, was not about immediate flights to other planets, but about the orbit, a space without a traditional place, yet imagined as being of paramount importance for strategic superiority. Driven by political tensions and drawing on representations established in physics and astronomy, the first satellite projects were designed and explained as missions to places that needed to be defined and controlled because they were strange and new. 

Description Test 

Relative changes in geomagnetic field intensity over the last 280 kyears have been recovered from the study of three marine cores from the Açores area. One core was precisely dated by oxygen isotope study and the other two records were linked to it using light reflectance analysis which allowed precise correlation. Rock magnetic analysis shows that the main magnetic mineral is magnetite with a very homogeneous grain-size distribution in the pseudo-single domain range for the three cores. Changes in the amount of magnetite do not exceed a factor of 10. Therefore, these cores appear to be suitable for relative palaeointensity determinations. Two mineral magnetic components with periodicities of 23 and 18 kyears are present in the records of bulk magnetic parameters and natural remanent magnetisation (NRM), but the power at these frequencies is not significant at the 95% level for the normalised remanence records. For each core, normalisation of the NRM using different normalising parameters yields virtually identical results. Using saturation isothermal remanent magnetisation (SIRM) as the normalising parameter, the results of the three cores were then combined into a stacked curve. Squared coherence analysis between this stacked curve and bulk mineral-magnetic parameters reveals that the 18 kyear component is still present in the record, but that the power spectrum is barely above noise level at this frequency. Some of the features of this North Atlantic record are consistent with the main characteristics already documented in other sedimentary or volcanic records. For instance, distinct periods of low intensity are observed around 40, 120, and 190 kyears, and periods of high intensity at 50 and 80 kyears. Because of the uniformity of the mineral-magnetic characteristics of the three cores, we suggest that this record may be a suitable palaeointensity reference curve for the Central North Atlantic Ocean region.