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ABSTRACT This study demonstrates the potential of developing a future Raman spectroscopy-based sensor system for monitoring carbonation of concrete structures. A tailored optical fibre Raman system was developed under the [...]

Environmental context Nitrate (NO3 − ) and ammonium (NH4 + ) are the most important soil nitrogen forms for plant growth. However, conventional extraction techniques may introduce artefacts affecting the measurement of plant-available N concentrations following sampling and sample preparation processes. This is the first study of the DGT technique being used to measure NO3 -N and NH4 -N in a wide range of soils, compared with conventional KCl extraction, and examined different factors that contribute to the plant-availability of these ions in soils. The knowledge would help to optimise soil nitrogen management practices, increase economic benefits and reduce environmental impacts. Rationale The availability of soil nitrogen for plant uptake can be affected by numerous soil factors such as soil texture, moisture and organic matter content, temperature and microbial activity. Conventional extraction techniques may affect the measurement of plant-available N concentrations following sampling and sample preparation processes, including drying, sieving, homogenising, freezing and thawing. The diffusive gradients in thin-films (DGT) technique can overcome some limitations of the conventional extraction techniques and has been used to successfully estimate the plant-available fractions of nutrients, such as P, K, Zn, Cu and Mn in soils. Therefore, it is important to evaluate the use of DGT for measuring NO3 − and NH4 + in a wide variety of soils and examine the factors that contribute to the plant-availability of these ions in soils. Methodology The experiment evaluated the ability of the DGT technique to measure NO3 -N and NH4 -N in soils using binding layers containing A520E anion exchange resin or Microlite® PrCH cation exchange resin, respectively. The DGT results were compared to those from conventional KCl extraction. Results The A520E- and PrCH-DGTs showed good detection limits for NO3 -N (6.90 µg L−1 ) and NH4 -N (6.23 µg L−1 ) and were able to measure potentially available NO3 -N and NH4 -N in unfertilised soils. The mass of NO3 -N and NH4 -N that accumulated on the DGT device increased linearly across soil concentrations ranging from 5 to 300 mg kg−1 NO3 -N (depending on soil type) and 5–300 mg kg−1 NH4 -N; which is equivalent to fertiliser rates of 75–450 kg ha−1 N. DGTs were used to measure potentially available NO3 -N and NH4 -N in ten soils with various physical and chemical properties. The DGT results were compared with conventional KCl extraction used to determine soil mineral N. DGT and KCl extraction measured values were significantly correlated with each other for NO3 -N (R 2  = 0.53; P -value 4 -N (R 2  = 0.20, P -value = 0.045). Discussion The results suggest that the two methods sample different N pools in the soils, with DGT targeting the NO3 -N and NH4 -N that are available in soil pore water and attached to labile solid phases.

Nonpolar resistive switching (RS), a combination of bipolar and unipolar RS, is demonstrated for the first time in a single nanowire (NW) system. Exploiting Ag@TiO2core–shell (CS) NWs synthesized by postgrowth shell formation, the switching mode is controlled by adjusting the current compliance effectively, tailoring the electrical polarity response. We demonstrate ON/OFF ratios of 105and 107for bipolar and unipolar modes, respectively. In the bipolar regime, retention times could be controlled up to 103s, and in the unipolar mode, >106s was recorded. We show how the unique dual-mode switching behavior is enabled by the defect-rich polycrystalline material structure of the TiO2shell and the interaction between the Ag core and the Ag electrodes. These results provide a foundation for engineering nonpolar RS behaviors for memory storage and neuromorphic applications in CSNW structures.

Two-dimensional (2D) layered semiconductors have recently emerged as attractive building blocks for next-generation low-power nonvolatile memories. However, challenges remain in the controllable fabrication of bipolar resistive switching circuit components from these materials. Here, the experimental realization of lateral memtransistors from monolayer single-crystal molybdenum disulfide (MoS2) utilizing a focused helium ion beam is reported. Site-specific irradiation with the focused probe of a helium ion microscope creates a nanometer-scale defect-rich region, bisecting the MoS2lattice. The reversible drift of these defects in the applied electric field modulates the resistance of the channel, enabling versatile memristive functionality. The device can reliably retain its resistance ratios and set/reset biases for 1180 switching cycles. Long-term potentiation and depression with sharp habituation are demonstrated. This work establishes the feasibility of ion irradiation for controllable fabrication of 2D memristive devices with promising key performance parameters, such as low power consumption. The applicability of these devices for synaptic emulation may address the demands of future neuromorphic architectures.

Urbanization, changes in land use and land cover (LULC), and an increase in population collectively have significant impacts on urban catchments. However, a vast majority of LULC studies have been conducted using readily available satellite imagery, which often presents limitations due to its coarse spatial resolution. Such imagery fails to accurately depict the surface characteristics and diverse spectrum of LULC classifications contained within a single pixel. This study focused on the highly urbanized Dry Creek catchment in Adelaide, South Australia and aimed to determine the impact of urbanization on spatiotemporal changes in LULC and its implications for the land surface condition of the catchment. Very high spatial resolution imagery was utilized to examine changes in LULC over the past four decades. Support Vector Machine-learning-based image classification was utilized to classify and identify the changes in LULC over the study area. The classification accuracy showed strong agreement, with a kappa value greater than 0.8. The findings of this analysis showed that extensive urban development, which expanded the built-up area by 34 km2, were responsible for the decline in grass cover by 43.1 km2over the last 40 years (1979–2019). Moreover, built-up areas, plantation, and water features, in contrast to grass cover, have demonstrated an increasing trend during the study period. The overall urban expansion over the study period was 136.6%. Urbanization intensified impervious area coverage, increasing the runoff coefficient, equivalent impervious area, and curve number by 60.6%, 60.6%, and 7.9%, respectively, while decreasing the retention capacity by 38.6%. These modifications suggest a potential variability in catchment surface runoff, prompting the need for further research to understand the surface runoff changes brought by the changes in LULC resulting from urbanization. The findings of this study can be used for land use planning and flood management.

Nanoscale materials are frequently coated with surface stabilization layers during growth that prevent flocculation in solution and facilitate processing technologies such as ink-jet device printing. Here, we show that few-nanometer-thick stabilization layers typically used swell in the presence of certain solvents and impart significant stresses to the nanomaterial that remains even after the solvent has evaporated. Solvent swelling of the surface layer dramatically enhances nanomaterial–substrate adhesion via the collapse of the stabilization layer during solvent evaporation, preventing stress relaxation. We demonstrate the stress modulation of Ag, Au, and Si nanowires functionalised with surface polymers and surfactant layers and detect strain levels between 0.1 and 0.6% using atomic force microscopy mechanical measurement and Raman spectroscopy. Dry-transferred nanowires exhibit poor adhesion and show no evidence of incorporated stress but become stressed immediately following solvent exposure. Strain engineering is demonstrated by coating nanowires with few-nanometer-thick solvent-responsive polymer layers.

John McCourt: The Years of Bloom: James Joyce in Trieste 1904-1920 (The Lilliput Press, 25 £) Scholars apart, when most people think of James Joyce's 47 years in self-imposed exile, [...]

Carlo Gebler: Father and I: A Memoir. (Little, Brown, 16.99 £) Anyone who's read The Cure (1994) or How To Murder a Man (1998) recognizes that Carlo Gebler is one [...]

Liam O'Flaherty: The Collected Short Stories of Liam O'Flaherty (Wolfhound Press, 50 £) Just as William Trevor and John McGahern are the great Irish short story writers of our time, [...]

Maeve Brennan: The Rose Garden (Counterpoint, $23 dollars) When The Springs of Affection was published three years ago, it was widely acclaimed. 'I had forgotten how pure and strong so [...]

Cole Moreton: Hungry for Home -- Leaving the Blaskets: A Journey from the Edge of Ireland (Viking. $23.95/14.99 £) Review by John Boland 'This is the end of the world,' [...]

Edited with an Introduction by Colm Toibin: The Penguin Book Of Irish Fiction (Viking; Hardcover: 25 £ UK/$40). By their nature, literary anthologies are both highly selective and very bitty [...]

David McKittrick, Seamus Kelters, Brian Feeney, and Chris Thornton: Lost Lives--The Stories of the Men, Women, and Children Who Died as a Result of the Northern Ireland Troubles (Mainstream Publishing, [...]

Roddy Doyle: A Star Called Henry (Viking Press, Hardcover; 16.99 £ stg./ $24.95) More than any other Irish writer of his generation, Roddy Doyle has created a highly distinctive and [...]

Colm Toibin: The Blackwater Lightship (Picador, Hardcover; 15 £ stg.) Gay love in the age of AIDS was at the heart of Colm Toibin's last novel, The Story of the [...]

Some books are so distinctive and create such an impact that they are hard acts to follow. One thinks of To Kill a Mockingbird, The Ginger Man, At Swim-Two-Birds, The [...]

The Springs of Affection By Maeve Brennan (Flamingo, 10.99 £ stg.) Set in suburban Dublin between the two world wars, these remarkable stories introduce the general public to a writer [...]

Here's the scenario: although the IRA orders its men to decommission arms, there is no negotiated peace settlement, and thus the hostilities never actually come to an end. No, that's […]

We combine ambient (air) and ultrahigh vacuum (UHV) scanning tunneling microscopy (STM) and spectroscopy (STS) investigations together with density functional theory (DFT) calculations to gain a subnanometer insight into the structure and dynamic of two-dimensional (2D) surface-supported molecular networks. The planar tetraferrocene-porphyrin molecules employed in this study undergo spontaneous self-assembly via the formation of hydrogen bonded networks at the gold substrate–solution interface. To mimic liquid phase ambient deposition conditions, film formation was accomplished in UHV by electro-spraying a solution of the molecule in chloroform onto an Au(111) substrate, thereby providing access to the full spectroscopic capabilities of STM that can be hardly attained under ambient conditions. We show that molecular assembly on Au (111) is identical in films prepared under the two different conditions, and in good agreement with the theoretical predictions. However, we observe the contrast found for a given STM bias condition to be different in ambient and UHV conditions despite the similarity of the structures, and we propose possible origins of the different imaging contrast. This approach could be valuable for the thorough characterization of surface systems that involve large molecules and are prepared mainly in ambient conditions.

Optically transparent photodetectors are crucial in next-generation optoelectronic applications including smart windows and transparent image sensors. Designing photodetectors with high transparency, photoresponsivity, and robust mechanical flexibility remains a significant challenge, as is managing the inevitable trade-off between high transparency and strong photoresponse. Here we report a scalable method to produce flexible crystalline Si nanostructured wire (NW) networks fabricated from silicon-on-insulator (SOI) with seamless junctions and highly responsive porous Si segments that combine to deliver exceptional performance. These networks show high transparency (∼92% at 550 nm), broadband photodetection (350 to 950 nm) with excellent responsivity (25 A/W), optical response time (0.58 ms), and mechanical flexibility (1000 cycles). Temperature-dependent photocurrent measurements indicate the presence of localized electronic states in the porous Si segments, which play a crucial role in light harvesting and photocarrier generation. The scalable low-cost approach based on SOI has the potential to deliver new classes of flexible optoelectronic devices, including next-generation photodetectors and solar cells.

Declan Kiberd: Irish Classics (Granta Books, 25 £) declan Kiberd's last book, Inventing Ireland: The Literature of the Modern Nation, commanded a lot of critical attention, and with good reason, [...]