Escherichia coli concentration, multiscale monitoring over the decade 2011–2021 in the Mekong basin, Lao PDR

Bacterial pathogens in surface waters may threaten human health, especially in developing countries, where untreated surface water is often used for domestic needs. The objective of the long-term multiscale monitoring of Escherichia coli concentration in stream water, and that of associated variables (temperature, electrical conductance, dissolved oxygen concentration and saturation, pH, oxidation-reduction potential, turbidity, and total suspended sediment concentration), was to identify the drivers of bacterial dissemination across tropical catchments. This data description paper presents three datasets (see section Data availability) collected at 31 sampling stations located within the Mekong river and its tributaries in Lao PDR (0.6–25,946 km2) from 2011 to 2021. The 1,602 records have been used to describe the hydrological processes driving in-stream Escherichia coli concentration during flood events, to understand land-use impact on bacterial dissemination on small and large catchment scales, to relate stream water quality and diarrhea outbreaks, and to build numerical models. The database may be further used e.g. to interpret new variables measured in the monitored catchments, or to map the health risk posed by fecal pathogens.

Impurity diffusion in ion implanted AlN layers on sapphire substrates by thermal annealing

We report on impurity diffusion in ion implanted AlN layers after thermal annealing. Silicon, tin, germanium, and magnesium ions were implanted into single-crystal AlN layers grown on sapphire substrates. By annealing at 1600oC, silicon and magnesium atoms were diffused in the AlN layer, while less change was observed in the distribution of germanium atoms. Silicon implantation introduced vacancy-related defects. By annealing at temperatures over 1300oC, the vacancy-related defects were reduced, while oxygen atoms were diffused from the substrate due to sapphire decomposition. We reproducibly achieved silicon-implanted AlN layers with electrical conductance by controlling the annealing temperature and distribution of silicon and oxygen concentrations.

Variation of rainwater quality in Visakhapatnam

The electrical conductance (EC) of rain waters at Visakhapatnam is studied for a three year period of 1991-93. Lower amounts of rainfall (RF) record higher conductivity values and vice-versa due to dilution process of the amount of rain. EC/RF ratios decrease from summer months to monsoon as the accumulation of salts during dry periods is drained off with the progress of monsoon rains. Visakhapatnam records higher ionic contents than other stations in India due to highly polluted industrial atmosphere. The ionic contents for Ca, Na, K and a are possibly increasing with time at Visakhapatnam.

Interlayer electron flow and field shielding in twisted trilayer graphene quantum dots

While multilayer graphene (MLG) possesses excellent intralayer electron mobility, its interlayer electrical conductance exhibits great diversity that results in exotic phenomena and various applications in electronic devices. Driven by a...

Low-Noise Mixed-Signal Electronics for Closed-Loop Control of Complex Photonic Circuits

An increasing research effort is being carried out to profit from the advantages of photonics not only in long-range telecommunications but also at short distances, to implement board-to-board or chip-to-chip interconnections. In this context, Silicon Photonics emerged as a promising technology, allowing to integrate optical devices in a small silicon chip. However, the integration density made possible by Silicon Photonics revealed the difficulty of operating complex optical architectures in an open-loop way, due to their high sensitivity to fabrication parameters and temperature variations. In this chapter, a low-noise mixed-signal electronic platform implementing feedback control of complex optical architectures is presented. The system exploits the ContactLess Integrated Photonic Probe, a non-invasive detector that senses light in silicon waveguides by measuring their electrical conductance. The CLIPP readout resolution has been maximized thanks to the design of a low-noise multichannel ASIC, achieving an accuracy better than −35 dBm in light monitoring. The feedback loop to stabilize the behaviour of photonic circuits is then closed in the digital domain by a custom mixed-signal electronic platform. Experimental demonstrations of optical communications at high data-rate confirm the effectiveness of the proposed approach.

Fabrication and Characterization of Environmentally Friendly Biochar Anode

Electrical power generation by means of electrochemical systems utilizing wastewaters is a global energy challenge tackling technique for which a creation of novel eco-friendly electrode materials is in high relevance. For this purpose a Rhodophyta algae derived activated biochar anode bound with a flaxseeds mucilage binder (5, 10, 20, 30 wt.%) was formed and characterized by thermogravimetric, Brunauer-Emmett-Teller (BET) analysis as well as conductivity and mechanical resistance determination. Activation technique with KOH prior to carbonization at 800 °C of algae was employed to obtain biocarbon with a large surface area. The highest specific surface area of 1298.49 m2/g was obtained with the binder-free sample and had a tendency to decrease with the increase of the binder content. It was estimated that biochar anodes are thermally stable at the temperature of up to 200 °C regardless of binder concentration. The concentration of the binder on the other hand had a significant influence in anodes mechanical resistance and electrical conductance: anode with 30 wt.% of the binder had the highest compressive strength equal to 104 bar; however, the highest conductivity was estimated in anode with 5 wt.% of the binder equal to 58 S/m. It is concluded that anode with 10 wt.% mucilage binder has the optimal properties necessary in MFC utilization.

East Asian Calligraphy Black Ink-Coated Paper as Flexible Conducting Electrode for Supercapacitor

East Asian calligraphy black ink (hereafter called simply “black ink”) is used to fabricate flexible conducting chromatography paper electrode by a simple and low-cost method. The black ink-coated paper was characterized by scanning electron microscopy, surface profiler, water contact angle measurement, electrical resistance measurement, X-ray photoelectron spectroscopy, and X-ray diffraction. The hydrophilicity slightly decreased after black ink coating but still provided good adhesion to the follow-up reduced graphene oxide/polyaniline/chitosan slurry coating for fabricating supercapacitor electrodes. A 1000-cycle repeated bending test with a bending radius of 5 mm revealed good conductance retention. Instrumental analyses indicated that the carbon black in the black ink was the main contributor to the electrical conductance. The supercapacitor with black-ink-coated paper electrodes exhibited an areal specific capacitance of up to 179.08 mF/cm² and coulomb efficiency of 80%. This confirmed that the black-ink-coated paper electrode could be feasibly applied to a supercapacitor. This black-ink-coated paper can be easily fabricated in resource-limited settings, and it provides new possibilities for the use of paper-based electrodes in flexible electronics.

Physicochemical investigation of some primitive water sources in district Champawat for potability and preservation of historical aesthetics, Uttarakhand, India

The present study deals with the assessment of physicochemical properties of spring water samples collected from the surroundings of Champawat city, Uttarakhand, India. The total of twenty-three parameters were analysed for the study including pH, total dissolved solids (TDS) (mg/L), electrical conductance (EC) (µS/cm), temperature (T) (°C), dissolved oxygen (DO) (mg/L), chloride (Cl- ) (mg/L), and uranium (U) (µg/L). The seasonal variation was also observed in these samples. In the hills, spring water has been the common source of public water supply from ancient times, therefore this study includes the springs that have survived from the distant past and were being used for drinking purpose at earlier time. However, with time, the quality of these water sources has depleted due to both natural and anthropogenic reasons to such an extent that two of these sources are not in use any more. The analysis has shown that pH of these samples ranged from 6.74 - 7.77, the highest values of TDS and nitrate (NO3 - ) were observed to be 500 mg/L and 39.1 mg/L respectively. This study can help determine the present state of these ancient water sources, which can be used as alternative water sources in the time of water supply crisis, and maintaining these historical water sources can be an example of sustainable development and preservation of historical aesthetics.

The spin-dependent properties of silicon carbide/graphene nanoribbons junctions with vacancy defects

We have designed high-efficient spin-filtering junctions composed of graphene and silicon carbide nanoribbons. We have calculated the spin and charge transport in the junction by non-equilibrium Green’s function formalism combined with the density functional theory to find its spin-dependent electrical conductance, thermal conductance and Seebeck coefficient. In addition, the effect of Si and C atoms vacancies on the transport properties of the junction has been carefully investigated. The enhanced spin-filtering is clearly observed due to the edge and vacancy effects. On the other hand, vacancy defects increase the electrical and spin conductances of the junctions. The results show that the considered junctions are half-metal with reduced thermal conductance which makes them a suitable spin-dependent thermoelectric device. Our results predict the promising potential of the considered junctions for application in spintronic devices.