Dramatic Flux Research Articles

An Extremely Young Protostellar Core, MMS 1/OMC-3: Episodic Mass Ejection History Traced by the Micro SiO Jet

We present ∼0.″2 (∼80 au) resolution observations of the CO(2–1) and SiO(5–4) lines made with the Atacama large millimeter/submillimeter array toward an extremely young intermediate-mass protostellar source (t dyn < 1000 yr), MMS 1 located in the Orion Molecular Cloud-3 region. We have successfully imaged a very compact CO molecular outflow associated with MMS 1, having deprojected lobe sizes of ∼1800 au (redshifted lobe) and ∼2800 au (blueshifted lobe). We have also detected an extremely compact (≲1000 au) and collimated SiO protostellar jet within the CO outflow. The maximum deprojected jet speed is measured to be as high as 93 km s−1. The SiO jet wiggles and displays a chain of knots. Our detection of the molecular outflow and jet is the first direct evidence that MMS 1 already hosts a protostar. The position–velocity diagram obtained from the SiO emission shows two distinct structures: (i) bow shocks associated with the tips of the outflow, and (ii) a collimated jet, showing the jet velocities linearly increasing with the distance from the driving source. Comparisons between the observations and numerical simulations quantitatively share similarities such as multiple-mass ejection events within the jet and Hubble-like flow associated with each mass ejection event. Finally, while there is a weak flux decline seen in the 850 μm light curve obtained with the James Clerk Maxwell Telescope/SCUBA 2 toward MMS 1, no dramatic flux change events are detected. This suggests that there has not been a clear burst event within the last 8 yr.

Easily scale 3D conductive gradient fiber membrane for contaminants removal and fouling mitigation under electrochemical assistance

An electrochemical membrane filtration system provides an innovative approach to enhance contaminant removal and mitigate membrane fouling. There is an urgent need to develop portable, versatile, and efficient electrochemical membranes for affordable wastewater treatment. Here, a 3D conductive gradient fiber membrane (CC/PVDF) with a gradient porous structure was prepared using a two-step phase inversion method. Methyl orange (MO) was utilized as model organic substance to investigate the electrochemical performance of the CC/PVDF membrane. At applied potentials of +2 V, +3 V, −2 V and −3 V, the removal efficiency of MO was 5.1, 5.3, 4.8, and 5.1 times higher than at 0 V. A dramatic flux loss of 35.02% occurred on the membrane without electrochemistry, interestingly, whereas the flux losses were only 23.59%–10.24% in the applied potential after 30 min of filtration, which were approximately 1.18, 1.28, 1.29 and 1.38 times as high as that without electrochemistry, respectively. The enhanced removal and anti-fouling performances of the membranes were attributed to the functions of electrochemical degradation, electrostatic repulsion, and electrically enhanced wettability. Electrochemical generation of Hydrogen peroxide, along with HO• radicals, was detected and direct electron transfer and HO• were proved to be the dominant oxidants responsible for MO degradation. The intermediate oxidation products were identified by mass spectrometry, and an electrochemical degradation pathway of MO was proposed based on bond-breaking oxidation, ring-opening reactions, and complete oxidation. All the findings emphasize that the ECMF system possesses superior efficiency and creative potential for water purification applications.

1H 0707‐495: An AGN is dimming its X‐ray light

AbstractWe report on one of the first science observations obtained during the Calibration and Verification phase of extended ROentgen Survey with an Imaging Telescope Array (eROSITA) aboard the Spectrum‐Roentgen‐Gamma (SRG) mission on the famous Narrow‐Line Seyfert 1 Galaxy 1H 0707‐495. 1H 0707‐495 is a highly variable AGN, with a complex, steep X‐ray spectrum, which has been the subject of intense studies with XMM‐Newton in the past. During the eROSITA observations, 1H 0707‐495 showed a dramatic flux drop in about 1 day. The source is brightest at the beginning of the observations, with rapid fluctuations in count rate, followed by a subsequent decline in count rate going down close to the background level. The mean amplitude variability is a factor of 58, with a 1 error confidence interval with factors between 31 and 235. Similar, large‐amplitude count‐rate changes are deduced from the XMM‐Newton EPIC‐pn and MOS2 light curves. The energy band up to only 0.8 keV is dominating the amplitude variability, followed by a sudden drop in variability above 0.8 keV. Such extreme ultrasoft and large‐amplitude flux variability in active galactic nuclei has not been detected with other X‐ray observations so far. A physical explanation for the timing and spectral properties is a combination of strong relativistic effects close to the black hole and absorption by an ionized partial coverer. From the high‐ to the low‐flux state, the partial coverer is obscuring an increasing part of the emitted X‐ray radiation. Ionized outflowing absorbers are more transparent in the soft X‐rays than neutral absorbers and thus show leakage effects in the soft X‐rays, explaining the ultrasoft light curve.

Optical and ultraviolet monitoring of the black hole X-ray binary MAXI J1820+070/ASASSN-18ey for 18 months

ABSTRACT MAXI J1820+070 is a low-mass black hole X-ray binary system with high luminosity in both optical and X-ray bands during its outburst periods. We present extensive photometry in the X-ray, ultraviolet, and optical bands, as well as densely cadenced optical spectra, covering the phase from the beginning of the optical outburst to ∼550 days. During the rebrightening process, the optical emission precedes the X-ray by 20.80 ± 2.85 days. The spectra are characterized by blue continua and emission features of Balmer series, He i, and He ii lines and a broad Bowen blend. The pseudo equivalent widths (pEWs) of emission lines are found to show anticorrelations with the X-ray flux measured at comparable phases, due to increased suppression by the optical continuum. At around the X-ray peak, the full widths at half-maximum (FWHMs) of Hβ and He ii λ4686 tend to stabilize at 19.4 and 21.8 Å, corresponding to the line-forming regions at radii of 1.7 and 1.3 R⊙ within the disc. We further analysed the absolute fluxes of the lines and found that the fluxes of Hβ and He ii λ4686 show positive correlations with the X-ray flux, favouring the suggestion that the irradiation model is responsible for the optical emission. However, the fact that X-ray emission experiences a dramatic flux drop at t ∼ 200 days after the outburst, while the optical flux only shows a little variation, suggests that additional energy such as viscous energy may contribute to the optical radiation, in addition to X-ray irradiation.

Correlating Physicochemical Properties of Commercial Membranes with CO2 Absorption Performance in Gas-Liquid Membrane Contactor

The gas-liquid membrane contactor (GLMC) is a promising alternative gas absorption/desorption configuration for effective carbon dioxide (CO2 ) capture. The physicochemical properties of membranes may synergistically affect GLMC performances, especially during the long-term operations. In this work, commercial polypropylene (PP) and polyvinylidene fluoride (PVDF) hollow fiber (HF) membranes were applied to explore the effects of their physicochemical properties on long-term CO2 absorption performances in a bench-scale GLMC rig. PP membranes with pore size of 19 nm, thickness of 0.046 mm, and porosity of 58% achieved high CO2 flux when feeding pure CO2 (5.4 and 24.4×10-3 mol/m2 .s using absorbents of water and 1M monoethanolamine (MEA), respectively) whereas PVDF membranes with pore size of 24 nm, thickness of 0.343 mm, and porosity of 84% presented a good CO2 separation performance from the simulated biogas using 1M MEA (6.8×10-3 mol/m2 .s and 99.9% CH4 recovery). When using water as absorbent, the coupled phenomena of membrane wetting and fouling restricted CO2 transport and resulted in continuous flux loss during the long-term operations. When using MEA as absorbent, both PP and PVDF membranes suffered dramatic flux decline. A series of membrane characterization tests revealed that the morphology, pore size, hydrophobicity, and stability of selected commercial membranes were greatly affected by MEA attack during long-term operations. Therefore, the selection criterion of microporous membranes for high-efficiency and long-term stable CO2 absorption in GLMC processes was proposed. It is envisioned that this study can shed light on improving existing membrane fabrication procedures and the application of novel membrane surface modification techniques to facilitate practical applications of the GLMC technology.

Resource recovery from digested manure centrate: Comparison between conventional and aquaporin thin-film composite forward osmosis membranes

We compared the performance of conventional and aquaporin thin-film composite forward osmosis (FO) membranes (denoted as HTI and AQP membrane, respectively) for concentration of digested manure centrate. Results show that the two FO membranes were capable to concentrate digested centrate for resource recovery. During concentration of digested manure centrate, a cohesive fouling layer formed on the HTI membrane surface, resulting in more dramatic flux decline and less fouling reversibility in comparison to the AQP membrane. The two FO membranes exhibited effective and comparable rejection of bulk organic matter, total phosphorus, and heavy metals, leading to their notable enrichment in digested manure centrate. By contrast, ammonium nitrogen (NH4+-N) was only retained by approximately 40% using the two FO membranes with a slightly higher retention by the HTI membrane, since it was less negatively charged. As a result, total nitrogen was ineffectively rejected by the two FO membranes. It is noteworthy that the HTI membrane also contributed to higher rejection of most antibiotics than the AQP membrane, possibly due to enhanced retention by the fouling layer and retarded forward diffusion. Results from this study evidence the outperformance of the AQP membrane as a new generation FO membrane over its conventional counterpart with respect to antifouling property, while further improvement in membrane selectivity, particularly of monovalent cations (e.g. NH4+-N), is needed to advance FO applications in resource recovery from challenging waste streams.

Effect of bubble characteristics and nozzle size on the membrane distillation enhanced by gas–liquid two-phase flow

Abstract This study investigates the membrane performance and fouling control in bubble-assisted sweeping gas membrane distillation with high concentration saline (333 K saturated solution) as feed. The results show that a longer bubbling interval (3 min) at a fixed bubbling duration of 30 s can most efficiently increase the flux enhancement ratio up to 1.518. Next, the flux increases with the gas flow rate under a relatively lower level, but tends to plateau after the threshold level (1.2 L·min−1). Compared to the non-bubbling case, the permeate flux reaches up to 1.623-fold at a higher bubble relative humidity of 80%. It was also found that greater flux enhancement can be achieved and, meanwhile, dramatic flux decline can be delayed for an intermittent bubbling system with a smaller nozzle size. These results accord well with the observations of fouling deposition in situ on the membrane surface with scanning electron microscope (SEM).

Mitigation of inorganic fouling on pressure retarded osmosis (PRO) membranes by coagulation pretreatment of the wastewater concentrate feed

Utilization of wastewater or wastewater concentrate as the feed solution in pressure retarded osmosis (PRO) via thin film composite (TFC) membranes causes rapid and significant fouling within the porous substrate and onto the polyamide selective layer facing the substrate. Scaling of calcium phosphate salts has been identified as the predominant cause for the severe PRO membrane fouling. In this study, an acidic coagulant, AlCl3, and a caustic coagulant, NaAlO2, are employed to remove the phosphate from the wastewater concentrate. Their optimal dosages are investigated in order to most effectively remove phosphate and maintain a mild pH environment. 1000 ml of AlCl3 and NaAlO2 pretreated and untreated wastewater concentrates are then used as the feed solutions in the PRO fouling studies. The untreated wastewater concentrate that is saturated with calcium phosphate causes a dramatic flux reduction of 45.2% during the first 360 min of the tests and further reduces to 30.7% after a 25% recovery of the wastewater concentrate. Results show that both AlCl3 and NaAlO2 pretreatments can increase the initial water flux to 25.5 LMH and 24.8 LMH at 20 bar respectively, and increase the normalized water flux to 66% and 64% respectively upon a total permeation volume of 250 ml. However, the AlCl3 pretreatment shows a lower water flux recovery after a hydraulic backwash and a faster flux reduction in the repeated fouling tests. Elemental analyses reveal that AlCl3 is less effective in silica removal from the wastewater concentrate, which causes silica condensation underneath the selective layer of the TFC membrane. NaAlO2 appears to be the more effective coagulant in both phosphate and silica removal for a prolonged PRO operation. Moreover, a critical water flux framework is developed to analyze the PRO calcium phosphate fouling, in order to determine the stable water flux at a given phosphate concentration or the maximum allowable phosphate concentration to achieve the target PRO flux and power density.

Multiwavelength approach to classifying transient events in the direction of M 31

Context. In the hunt for rare time-domain events, it is important to consider confusing exotic extragalactic phenomena with more common Galactic foreground events. Aims. We show how observations from multiple wavebands, in this case optical and X-ray observations, can be used to facilitate the distinction between the two. Methods. We discovered an extremely bright and rapid transient event during optical observations of the M 31 galaxy taken by the intermediate Palomar Transient Factory (iPTF). The persistent optical counterpart of this transient was previously thought to be a variable star in M 31 without any dramatic flux excursions. The iPTF event initially appeared to be an extraordinarily rapid and energetic extragalactic transient, which had a ≈3 mag positive flux excursion in less than a kilosecond; one of the exciting possibilities was this event could be a very fast nova in M 31. The nature of the source was resolved with the help of Chandra archival data, where we found an X-ray counterpart and obtained its X-ray spectrum. Results. We find the X-ray spectrum of the quiescent emission can be described by a model of optically thin plasma emission with a temperature of ≈7 MK, typical for coronal emission from an active star. The combination of the X-ray luminosity, which is calculated assuming the source is located in M 31 (~3 × 1036 erg s−1), and the color temperature exclude any type of known accreting compact object or active star in M 31. We argue instead that the optical transient source is an M-type main-sequence, active star located in the disk of the Milky Way at a distance of ~0.5–1 kpc. Its persistent X-ray luminosity is in the ≈1.3–5 × 1030 erg s−1 range and it has the absolute optical magnitude of 9.5–11.0 mag in the R band. The observed optical flare has the equivalent duration of ≈95 min and total energy of ≈(0.3–1) × 1035 erg in the R band, which places it among the brightest flares ever observed from an M-type star. This case can serve as an example for the classification of Galactic and extragalactic events in upcoming high-cadence time-domain projects, such as the Zwicky Transient Facility and the Large Synoptic Survey Telescope.

Empirical Characterization of Low‐Altitude Ion Flux Derived from TWINS

AbstractIn this study we analyze ion differential flux from 10 events between 2008 and 2015. The ion fluxes are derived from low‐altitude emissions (LAEs) in energetic neutral atom (ENA) images obtained by Two Wide‐angle Imaging Neutral‐atom Spectrometers (TWINS). The data set comprises 119.44 hr of observations, including 4,284 per energy images with 128,277 values of differential ENA flux from pixels near Earth's limb. Limb pixel data are extracted and mapped to a common polar ionospheric grid and associated with values of the Dst index. Statistical analysis is restricted to pixels within 10% of the LAE emissivity peak. For weak Dst conditions we find a premidnight peak in the average ion precipitation, whose flux and location are relatively insensitive to energy. For moderate Dst, elevated flux levels appear over a wider magnetic local time (MLT) range, with a separation of peak locations by energy. Strong disturbances bring a dramatic flux increase across the entire nightside at all energies but strongest for low energies in the postmidnight sector. The arrival of low‐energy ions can lower the average energy for strong Dst, even as it raises the total integral number flux. TWINS‐derived ion fluxes provide a macroscale measurement of the average precipitating ion distribution and confirm that convection, either quasi‐steady or bursty, is an important process controlling the spatial and spectral properties of precipitating ions. The premidnight peak (weak Dst), MLT widening and energy‐versus‐MLT dependence (moderate Dst), and postmidnight low‐energy ion enhancement (strong Dst) are consistent with observations and models of steady or bursty convective transport.

Effect of on the Membrane Distillation of PVDF Membrane Material Enhanced by Gas-Liquid Two-Phase Flow

This study investigates the membrane performance and fouling control in the bubble-assisted sweeping gas membrane distillation with high concentration saline (333 K saturated solution) as feed. The results show that longer bubbling interval (3 min) at a fixed bubbling duration of 30s can most efficiently increase the the flux enhancement ratio up to 1.518. Next, the flux increases with the gas flowrate under a relatively lower level, but tends to a plateau after the threshold level (1.2 L•min-1). Compared to non-bubbling case, the permeate flux reaches up to 1.623 fold at a higher bubble relative humidity of 80 %. It was also found that greater flux enhancement can be achieved and meanwhile dramatic flux decline can be delayed for an intermittent bubbling system with a smaller nozzle size. These results accord well with the observations of fouling deposition in situ on the membrane surface with SEM.

Fouling behavior and scaling mitigation strategy of CaSO4 in submerged vacuum membrane distillation

Fouling and scaling in membrane distillation (MD) is one of the major obstacles to its long term stability. Submerging the membrane directly into the feed is an alternative method to prevent flow channel blockage. The fouling behavior of CaSO4 in submerged vacuum membrane distillation at varying experimental conditions was investigated. It presented a two-stage trend when the initial concentration of CaSO4 was <2700mg/L. Dramatic flux decline occurred once the feed was concentrated to a critical level of saturation. A on-line periodically air backwash was applied to reduce CaSO4 crystals deposition on the membrane surface or penetration in the membrane pores. While the role of air bubbles in affecting the fouling behavior of CaSO4 largely depended on the crystal formation mechanism. The fouling rate was reduced by 54% with the help of air backwash when surface crystallization controlled the process while negligible effect was made when bulk crystallization played a more important role. The result could be explained by combining the experimental data with a first-order kinetic model proposed by Tansel. The off-line water cleaning suggested that the fouling layer could be removed effectively without additional chemical agent.

Osmotic membrane bioreactors for wastewater reuse: Performance comparison between cellulose triacetate and polyamide thin film composite membranes

This study compared the performance of the asymmetric cellulose triacetate (CTA) and polyamide thin film composite (TFC) forward osmosis (FO) membranes in an osmotic membrane bioreactor (OMBR). A reverse osmosis (RO) system was integrated with OMBR to regenerate the draw solution and produce clean water. Results show that the TFC membrane exhibited a higher initial water flux but more dramatic flux decline compared to the CTA membrane when they were used for OMBR. The CTA and TFC membranes also resulted in discernible difference in salinity build-up in the bioreactor and thus biomass characteristics during OMBR operation. All 30 trace organic contaminants (TrOCs) selected in this study were effectively removed by the OMBR-RO hybrid system regardless of the FO membrane type. Compared to the CTA membrane, the TFC membrane contributed more significantly toward the removal of hydrophilic and biologically persistent compounds and thus reduced their accumulation in the draw solution during OMBR-RO operation. In addition, CTA and TFC FO membranes also resulted in considerable differences in TrOC residuals in the sludge during OMBR operation.

Investigations of inorganic and organic fouling behaviors, antifouling and cleaning strategies for pressure retarded osmosis (PRO) membrane using seawater desalination brine and wastewater

By employing seawater desalination brine (SWBr) and wastewater brine (WWBr) as the feed pair, membrane fouling behaviors as well as antifouling and cleaning strategies for the state-of-the-art thin-film composite polyethersulfone (TFC-PES) hollow fiber membrane have been systematically investigated under pressure retarded osmosis (PRO) operations. Fouling on the polyamide selective layer induced by the SWBr draw solution is relatively mild because of the outstanding membrane rejection and the hydration antifouling layer formed by the permeating water. However, using WWBr as the feed causes fast and severe internal concentration polarization (ICP) and fouling within the porous PES substrate, which result in dramatic flux and power density declines. In addition, the PRO fouling upon and within the porous substrate is highly irreversible. Experimental data show that both anti-scalant pretreatment and pH adjustment of WWBr could effectively mitigate inorganic fouling, while increasing feed flow velocity along the substrate surface is ineffective for fouling control. To clean the fouled membranes, hydraulic-pressure induced backwash and flushing with alkaline and NaOCl solutions on the fouled surface are effective strategies to remove foulants and regenerate membranes with a flux recovery of 83–90%. However, osmotic backwash shows low cleaning efficiency in PRO. In summary, a proper combination of feed pretreatment and membrane cleaning strategies has been demonstrated in this study to sustain PRO operations with a high water flux and power density.

Factors Governing the Distribution and Abundance of Arctic Ground Squirrels

Extinction is the most extreme future state for any wildlife population. In Canada’s northern montane boreal regions, the disappearance of any small herbivore will have consequences for the way energy flows between trophic levels. Arctic ground squirrels (Urocitellus parryii plesius) were once so plentiful as to be responsible for approximately one-quarter of the energy flow at the herbivore level (Boonstra et al., 2001). However, population dynamics of this species over the past decade serve as a potent example of how northern regions may now be in dramatic flux. The Arctic ground squirrel is the largest ground squirrel in North America and has the most northerly distribution (Fig. 1). It lives throughout the montane boreal, alpine, and tundra regions and hibernates from September to mid-April (Naughton, 2012). In the Yukon, it is an important seasonal food source for many predators, including lynx (Lynx canadensis), coyote (Canis latrans), red fox (Vulpes vulpes), wolf (Canis lupus), black bear (Ursus americanus), grizzly bear (Ursus arctos), wolverine (Gulo gulo), Red-tailed Hawk (Buteo jamaicensis), Northern Goshawk (Accipiter gentilis), and Golden Eagle (Aquila chrysaetos). Arctic ground squirrels are also hunted by Yukon First Nations as a traditional source of food. Population fluctuations of Arctic ground squirrels therefore affect the food supply available to a wide list of predators. For almost three decades (1973 – 99), ground squirrel populations in the boreal forests of the Kluane region (SW Yukon) cycled in a predictable manner (Werner et al., 2015b) in concert with the snowshoe hare (Lepus americanus; Boutin et al., 1995). This 9 – 10 year cycle was stable up until 2000. In that year, populations crashed, and they have not, as yet, recovered. This once important species declined from 17% of the regional herbivore biomass to nearly zero. Most boreal forest populations (~95%) are now extinct, as are a large fraction (~65%) of nearby meadow populations. I am now conducting experiments and surveys designed to clarify the likely causes and consequences of these dramatic changes. The measures described below are intended to address a number of specific research projects.

MAPPING THE SURFACE OF THE MAGNETAR 1E 1048.1–5937 IN OUTBURST AND QUIESCENCE THROUGH PHASE-RESOLVED X-RAY SPECTROSCOPY

We model the pulse profiles and the phase resolved spectra of the anomalous X-ray pulsar 1E 1048.1-5937 obtained with XMM-Newton to map its surface temperature distribution during an active and a quiescent epoch. We develop and apply a model that takes into account the relevant physical and geometrical effects on the neutron star surface, magnetosphere, and spacetime. Using this model, we determine the observables at infinity as a function of pulse phase for different numbers and sizes of hot spots on the surface. We show that the pulse profiles extracted from both observations can be modeled with a single hot spot and an antipodal cool component. The size of the hot spot changes from $\approx 80^{\circ}$ in 2007, 3 months after the onset of a dramatic flux increase, to $\approx 30^{\circ}$ during the quiescent observation in 2011, when the pulsed fraction returned to the pre-outburst $\approx$ 65\% level. For the 2007 observation, we also find that a model consisting of a single 0.4 keV hot spot with a magnetic field strength of $1.8 \times 10^{14}$ G accounts for the spectra obtained at three different pulse phases but under predicts the flux at the pulse minimum, where the contribution to the emission from the cooler component is non-negligible. The inferred temperature of the spot stays approximately constant between different pulse phases, in agreement with a uniform temperature, single hot spot model. These results suggest that the emitting area grows significantly during outbursts but returns to its persistent and significantly smaller size within a few year timescale.

EXTREMELY HIGH POLARIZATION IN THE 2010 OUTBURST OF BLAZAR 3C 454.3

The gamma-ray-detected blazar 3C 454.3 exhibits dramatic flux and polarization variations in the optical and near-infrared bands. In December 2010, the object emitted a very bright outburst. We monitored it for approximately four years (including the 2010 outburst) by optical and near-infrared photopolarimetry. During the 2010 outburst, the object emitted two rapid, redder brightenings, at which the polarization degrees (PDs) in both bands increased significantly and the bands exhibited a frequency-dependent polarization. The observed frequency-dependent polarization leads us to propose that the polarization vector is composed of two vectors. Therefore, we separate the observed polarization vectors into short and long-term components that we attribute to the emissions of the rapid brightenings and the outburst that varied the timescale of days and months, respectively. The estimated PD of the short-term component is greater than the maximum observed PD and is close to the theoretical maximum PD. We constrain the bulk Lorentz factors and inclination angles between the jet axis and the line of sight from the estimated PDs. In this case, the inclination angle of the emitting region of short-term component from the first rapid brightening should be equal to 90$^{\circ}$, because the estimated PD of the short-term component was approximately equal to the theoretical maximum PD. Thus, the Doppler factor at the emitting region of the first rapid brightening should be equal to the bulk Lorentz factor.

Gradual diffusion and punctuated phase space density enhancements of highly relativistic electrons: Van Allen Probes observations

AbstractThe dual‐spacecraft Van Allen Probes mission has provided a new window into mega electron volt (MeV) particle dynamics in the Earth's radiation belts. Observations (up to E ~10 MeV) show clearly the behavior of the outer electron radiation belt at different timescales: months‐long periods of gradual inward radial diffusive transport and weak loss being punctuated by dramatic flux changes driven by strong solar wind transient events. We present analysis of multi‐MeV electron flux and phase space density (PSD) changes during March 2013 in the context of the first year of Van Allen Probes operation. This March period demonstrates the classic signatures both of inward radial diffusive energization and abrupt localized acceleration deep within the outer Van Allen zone (L ~4.0 ± 0.5). This reveals graphically that both “competing” mechanisms of multi‐MeV electron energization are at play in the radiation belts, often acting almost concurrently or at least in rapid succession.

German Women's Poetry Circa 1900: A Forgotten Anthology

The anthology Frauenlyrik unserer Zeit (1907), edited by the artist‐writer Julia Virginia Scheuermann, appeared at a pivotal moment in literary history when the economic conditions for poetry, aesthetic tastes, and women's roles in society were in dramatic flux. In this article, I examine those dynamic conditions and the influence such anthologies once attained as quintessential social and cultural projects. I propose that the intermediality of this unique collection marks it as a transitional project that bridged the private and public spheres and illustrated the expansion of women's writing. I argue that the author's rights movement, advanced by the Kartell lyrischer Autoren, influenced the stylistic and ideological heterogeneity of the collection. By boldly defining the emergence of women's writing in the early twentieth century in terms of universal human history (Menschheitsgeschichte), Scheuermann proposes a narrative rationale for the lyric genre that endures in later modernist projects.

Effect of low dosage of coagulant on the ultrafiltration membrane performance in feedwater treatment

One of the critical issues for the widely application of ultrafiltration (UF) in water treatment is membrane fouling owning to the dissolved organic matter. The aim of the present study is to explore the effect of various particle sizes caused by low dosages of coagulant with dissolved organic matter on the UF membrane performance. Aluminum chloride was added to the synthetic water with the hydrophobic humic acid (HA), the hydrophilic bovine serum albumin (BSA) – a protein- and their 1:1 (mass ratio) mixture. The results showed that there was a critical dose of Al that could cause dramatic flux reduction by blocking the membrane pores after coagulating with HA/BSA. For HA or BSA, the critical dose of Al was relatively lower at pH 6.0 than that at pH 8.0. After coagulation, the flux decline caused by HA was slightly varied as a function of pH while that caused by BSA was greatly affected by pH. The flux decline caused by the 1:1 (mass ratio) HA/BSA mixture after coagulation was similar to that caused by HA after coagulation because BSA could be encapsulated by HA. In addition, the peak value of the molecular weight (MW) distribution of HA coagulated with Al was changed more drastically compared to that of BSA after filtration.