Fiber Optic Sensing Textile for Strain Monitoring in Composite Substrates.

Composite polymers have become widely used in industries such as the aerospace, automobile, and civil construction industries. Continuous monitoring is essential to optimize the composite components' performance and durability. This paper describes the concept of a distributed fiber optic smart textile (DFOST) embedded into a composite panel that can be implemented during the fabrication process of bridges, planes, or vehicles without damaging the integrity of the composite. The smart textile used an embroidery method to create DFOST for easy installation between composite laminates. It also allows different layout patterns to provide two- or three-dimensional measurements. The DFOST system can then measure strain, temperature, and displacement changes, providing critical information for structural assessment. The DFOST was interrogated by using an optical frequency domain reflectometry (OFDR). It could measure strain variation during the dynamic and static test with a spatial resolution of 2 mm and a minimum strain resolution of 10 µÏµ. This paper focuses on the study of strain measurement.

Fe and Zn Metal Nanocitrates as Plant Nutrients through Soil Application.

Nanocitrates of iron (Fe) and zinc (Zn) in the form of plant nanonutrients were examined for their behavior in soil and the uptake of these by 20-day old groundnut (Arachis hypogaea) seedlings under greenhouse conditions. The Fe (0.04 to 0.008 mmol/kg of soil) and Zn (0.02 to 0.004 mmol/kg of soil) nanocitrates were applied to soil and compared with commercial counterparts (FeSO4, ZnSO4, nano-Fe, nano-Zn, Fe-EDTA, Zn-EDTA). The combined nanocitrate compositions were also formulated by physical means and characterized. The plant uptake of Fe and Zn was determined through atomic absorption spectrometry (AAS). All the treated plants showed good germination and higher vigor indexes compared to the control treatments. The highest available Fe and Zn soil contents after leaching were 150.5 and 18.9 mg/kg, respectively, in combined nanocitrate compositions, whereas in the control (untreated) soil, the Fe and Zn contents were 6.0 and 0.7 mg/kg, respectively. The plant's Fe content was 0.48 mg/pot for the combined nanocitrate composition, and that of the untreated plant sample was 0.02 mg/pot. The plant's Zn content was 82.3 µg/pot for pure zinc citrate, and the respective untreated-plant Zn content was 2.1 µg/pot. These values are better than those observed for commercial fertilizers. Additionally, no trend in promotional and antagonistic correlations between Fe and Zn in combined nanocitrates was observed in the studied period (20 days in duration). Among the 34 synthesized citrates, six nanocitrates show promising trends for evaluation under field conditions with higher stability.

Metal citrate nanoparticles: a robust water-soluble plant micronutrient source.

A series of iron (Fe) and zinc (Zn) plant nanonutrients in citrate form were prepared by an eco-friendly solid-state grinding of the respective nitrates and citric acid. Ball-milling of the as-prepared Fe and Zn citrates resulted in nanosize particles. The as-prepared and ball-milled Fe and Zn citrates were characterized using Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis and differential thermal analysis (TGA/DTA), and powder X-ray diffraction (XRD). The particle size and morphology of the obtained samples were studied using a scanning electron microscope (SEM) and transmission electron microscope (TEM). The obtained nanosized Fe and Zn citrates were analyzed for their plant uptake in the test crop soybean (var. JS-335) using the white-sand technique. The concentration of nutrients was estimated by atomic absorption spectrometry (AAS). A significant increase in nutrient absorption was observed in 6 h ball-milled samples of both Fe (789.8 µg per g of dry weight) and Zn (443.8 µg per g of dry weight) citrates. Such an increased nutrient absorption is due to the high mobility of nanocitrates. Therefore, nanocitrates can serve as an excellent source of plant nutrients in agriculture.

New gold standard: weakly capped infant Au nanoclusters with record high catalytic activity for 4-nitrophenol reduction and hydrogen generation from an ammonia borane-sodium borohydride mixture.

Increasing the surface area-to-volume ratio of materials through size reduction is a desired approach to access maximum possible surface sites in applications such as catalysis. However, increase in the surface energy with the decrease in dimension warrants strong ligands to stabilize nanosystems, which mask the accessibility of the active surface sites. Owing to this, the realization of the true potential of a catalyst's surface remains challenging. Here, we employed a rationally designed strategy to synthesize infant Au nanoclusters-that alleviates the requirement of any separate ligand removal step-to unleash their actual potential to register a record high maximum turn-over frequency (TOFmax) of 72 900 h-1 and 65 500 h-1 in the benchmark catalytic reduction of 4-nitrophenol and catalytic H2 generation from an ammonia borane-sodium borohydride mixture, respectively. Such a phenomenal catalytic activity has been realized via the synthesis and stabilization of Au nanoclusters using solid citric acid and a super-concentrated aqueous AuCl3 solution, a pathway entirely different from the conventional modifications of the Turkevich and Brust methods. The crux of the synthetic strategy lies in precise control of the water content and thereby ensuring that the final Au nanoclusters remain in the solid state. During the synthesis, citric acid not only acts as a reducing agent to yield 'infant' Au nanoclusters but also provides a barrier matrix to arrest their growth. In solution, its weak capping ability and rapid dissolution allows the reactants to easily access the active sites of Au nanoclusters, thus leading to faster catalysis. Our study reveals that the true potential of metal nanoclusters as catalysts is actually far higher than what has been reported in the literature.

Effect of a behaviour-change intervention on handwashing with soap in India (SuperAmma): a cluster-randomised trial.

BACKGROUND: Diarrhoea and respiratory infections are the two biggest causes of child death globally. Handwashing with soap could substantially reduce diarrhoea and respiratory infections, but prevalence of adequate handwashing is low. We tested whether a scalable village-level intervention based on emotional drivers of behaviour, rather than knowledge, could improve handwashing behaviour in rural India. METHODS: The study was done in Chittoor district in southern Andhra Pradesh, India, between May 24, 2011, and Sept 10, 2012. Eligible villages had a population of 700-2000 people, a state-run primary school for children aged 8-13 years, and a preschool for children younger than 5 years. 14 villages (clusters) were selected, stratified by population size (<1200 vs >1200), and randomly assigned in a 1:1 ratio to intervention or control (no intervention). Clusters were enrolled by the study manager. Random allocation was done by the study statistician using a random number generator. The intervention included community and school-based events incorporating an animated film, skits, and public pledging ceremonies. Outcomes were measured by direct observation in 20-25 households per village at baseline and at three follow-up visits (6 weeks, 6 months, and 12 months after the intervention). Observers had no connection with the intervention and observers and participant households were told that the study was about domestic water use to reduce the risk of bias. No other masking was possible. The primary outcome was the proportion of handwashing with soap at key events (after defecation, after cleaning a child's bottom, before food preparation, and before eating) at all follow-up visits. The control villages received a shortened version of the intervention before the final follow-up round. Outcome data are presented as village-level means. FINDINGS: Handwashing with soap at key events was rare at baseline in both the intervention and control groups (1% [SD 1] vs 2% [1]). At 6 weeks' follow-up, handwashing with soap at key events was more common in the intervention group than in the control group (19% [SD 21] vs 4% [2]; difference 15%, p=0·005). At the 6-month follow-up visit, the proportion handwashing with soap was 37% (SD 7) in the intervention group versus 6% (3) in the control group (difference 31%; p=0·02). At the 12-month follow-up visit, after the control villages had received the shortened intervention, the proportion handwashing with soap was 29% (SD 9) in the intervention group and 29% (13) in the control group. INTERPRETATION: This study shows that substantial increases in handwashing with soap can be achieved using a scalable intervention based on emotional drivers. FUNDING: Wellcome Trust, SHARE.

Turbulent shearing of crude oil mixed with dispersants generates long microthreads and microdroplets.

Using cinematic digital holography, we demonstrate that turbulent breakup of crude oil mixed with dispersants into microdroplets starts with the formation of very long and quite stable, single or multiple microthreads that trail behind 300-1400 microm droplets. These threads extend from Reynolds number dependent regions with high surfactant concentration, which, along with associated viscosities and stretching by turbulence stabilizes the threads. The subsequent breakup, producing 2.8 microm droplets, is due to an increasing surface area and diffusion of dispersants into the continuous phase.

Lattice-solvent controlled spin transitions in iron(II) complexes.

A series of spin transition (ST) iron(II) compounds of the type [FeII2](X)2.{S}2 (where is 4'-(4'''-cyanophenyl)-1,2':6'1''-bispyrazolylpyridine, X=ClO4- or BF4-, and S is acetonitrile) was synthesized and magnetically investigated. The effects of the removal of the lattice-solvent molecules and of their different positions relative to the iron(II) cations on the ST process were investigated. Crystallization yields orange block (A.{S}2) crystals of the composition [FeII()2](ClO4)2.{S}2, and two polymorphic compounds of the stoichiometry [FeII()2](BF4)2.{S}2 as red coffin (B.{S}2) and orange block (C.{S}2) crystals. The Fe-N bond distances of A.{S}2 (from 1.921(9) to 1.992(3) A; at 150 K), B.{S}2 (from 1.943(2) to 2.017(2) A; at 180 K) and C.{S}2 (from 1.883(3) to 1.962(3) A; at 180 K) indicate low spin (LS) states of the respective iron(II) ions. Notably, the observed small difference in the Fe-N distances at 180 K for the two polymorphs B.{S}2and C.{S}2 are due to different positions of the acetonitrile molecules in the crystal lattices and illustrate the sensitivity of the spin transition properties on lattice-solvent effects. Variable-temperature single crystal X-ray studies display single-crystal thermochroism (red (LS)<-->orange (HS)) for A.{S}2 and B.{S}2 and ca. 3.6% decrease in the unit cell volume of A.{S}2 from 4403 A3 at 300 K to 4278 A3 at 150 K. The temperature dependent magnetic susceptibilities of A.{S}2 and B.{S}2 demonstrate systematic increase of the spin transition temperatures (T1/2) and continuous decreases of the hysteresis loop width (DeltaT1/2) upon slow lattice-solvent exclusion.