Improving water security through rainwater harvesting: a case from Guatemala and the potential for expanding coverage

Municipal infrastructure for water supply and delivery often does not reach populations in rural and peri-urban areas. This article examines rainwater harvesting as a means of increasing water security in such areas, through the case of Guachtuq, a peri-urban community outside San Cristóbal, Alta Verapaz, Guatemala. The project team designed a rainwater harvesting system to improve three dimensions of water security: quantity, quality and access. The design was implemented for 12 households and evaluated for its contribution to water security and for the potential of expanding project coverage to the region and beyond. The system has improved water security. Several concerns remain, however, regarding the potential of expanding the project to other households in the region and beyond, including system cost, water quality and the individualization of public responsibility for water security.     

Metabolomic Profiling of Plasma from Melioidosis Patients Using UHPLC-QTOF MS Reveals Novel Biomarkers for Diagnosis

To identify potential biomarkers for improving diagnosis of melioidosis, we compared plasma metabolome profiles of melioidosis patients compared to patients with other bacteremia and controls without active infection, using ultra-high-performance liquid chromatography-electrospray ionization-quadruple time-of-flight mass spectrometry. Principal component analysis (PCA) showed that the metabolomic profiles of melioidosis patients are distinguishable from bacteremia patients and controls. Using multivariate and univariate analysis, 12 significant metabolites from four lipid classes, acylcarnitine (n = 6), lysophosphatidylethanolamine (LysoPE) (n = 3), sphingomyelins (SM) (n = 2) and phosphatidylcholine (PC) (n = 1), with significantly higher levels in melioidosis patients than bacteremia patients and controls, were identified. Ten of the 12 metabolites showed area-under-receiver operating characteristic curve (AUC) >0.80 when compared both between melioidosis and bacteremia patients, and between melioidosis patients and controls. SM(d18:2/16:0) possessed the largest AUC when compared, both between melioidosis and bacteremia patients (AUC 0.998, sensitivity 100% and specificity 91.7%), and between melioidosis patients and controls (AUC 1.000, sensitivity 96.7% and specificity 100%). Our results indicate that metabolome profiling might serve as a promising approach for diagnosis of melioidosis using patient plasma, with SM(d18:2/16:0) representing a potential biomarker. Since the 12 metabolites were related to various pathways for energy and lipid metabolism, further studies may reveal their possible role in the pathogenesis and host response in melioidosis.     

Simulation study on acoustic streaming and convective cooling in blood vessels during a high-intensity focused ultrasound thermal ablation

This study investigates the influence of blood vessels on temperature distribution during high-intensity focused ultrasound (HIFU) ablation of liver tumors. A three-dimensional acoustics-thermal-fluid coupling model is simulated to compute the temperature field in the hepatic cancerous region. The model is based on the linear Westervelt and bioheat equations as well as the non-linear Navier–Stokes equations for the liver parenchyma and blood vessels. The effect of acoustic streaming is also taken into account in the present HIFU simulation study. We found from this three-dimensional coupling study that in large blood vessel both the convective cooling and acoustic streaming can significantly change the temperature field and thermal lesion near blood vessels.     

Hardware architecture of the Protein Processing Associative Memory and the effects of dimensionality and quantisation on performance

The Protein Processor Associative Memory (PPAM) is a novel hardware architecture for a distributed, decentralised, robust and scalable, bidirectional, hetero-associative memory, that can adapt online to changes in the training data. The PPAM uses the location of data in memory to identify relationships and is therefore fundamentally different from traditional processing methods that tend to use arithmetic operations to perform computation. This paper presents the hardware architecture and details a sample digital logic implementation with an analysis of the implications of using existing techniques for such hardware architectures. It also presents the results of implementing the PPAM for a robotic application that involves learning the forward and inverse kinematics. The results show that, contrary to most other techniques, the PPAM benefits from higher dimensionality of data, and that quantisation intervals are crucial to the performance of the PPAM.     

Electrical characteristics of high dielectric constant BCTZ thin films

Abstract

High dielectric constant Ba_0.96Ca_0.04Ti_0.84Zr_0.16O₃ (BCTZ) thin films were deposited on Pt/Ti/SiO₂/Si substrates by spin on metal-organic decomposition (MOD) technique. Undoped and 0.4% Mg-doped BCTZ thin films were annealed in the temperature range from 600 to 900 °C for 1 hour in oxygen environment. The crystal structure of BCTZ thin films was analyzed by X-ray diffraction. The electrical properties of BCTZ thin films were investigated by capacitance—voltage (C—V) characteristics. Also, the electrical properties of these films were compared in conjunction with 0.4% Mg doping effect of BCTZ thin films for possible high dielectric constant material applications.     

Fault Ride-Through Capability Enhancement of VSC HVDC connected Offshore Wind Power Plants

To achieve active control of the AC voltage magnitude of wind power plant(WPP) collector network and improve the fault ride-through (FRT) capability,an FRT scheme based on feed forward DC voltage contr...     

Characterizing In‐Plane Geometrical Variability in Textile Ceramic Composites

We present a methodology for characterizing and reconstructing in‐plane weave variability in textile composites. Surface topography of a partially processed C‐fiber/SiC matrix composite panel was measured using digital image correlation. The centroids of tow segments that appear periodically on the fabric surface were located by image analysis and used as fiducial markers. Stochastic deviations of the fiducial markers from the ideal periodic weave structure indicate geometrical variance. Fourier analysis shows that spatial wavelengths of the deviations range from the size of one unit cell to the dimensions of the entire panel. Long‐range deviations are attributed principally to fabric deformation after manufacture, during handling. Short‐range fluctuations, extracted by computing spatial derivatives of the positions of the fiducial markers, are attributed to variations in tow packing density that arises during weaving. A simple set of statistics for these deviations is presented and its use in generating stochastic virtual specimens is demonstrated.     

Soft X‐ray Ptychographic Imaging and Morphological Quantification of Calcium Silicate Hydrates (C–S–H)

Morphological details of calcium silicate hydrate (C–S–H) stemming from the hydration process of Portland cement (PC) phases are crucial for understanding the PC‐based systems but are still only partially known. Here we introduce the first soft X‐ray ptychographic imaging of tricalcium silicate (C₃S) hydration products. The results are compared using both scanning transmission X‐ray and electron transmission microscopy data. The evidence shows that ptychography is a powerful method to visualize the details of outer and inner product C–S–H of fully hydrated C₃S, which have fibrillar and an interglobular structure with average void sizes of 20 nm, respectively. The high‐resolution ptychrography image enables us to perform morphological quantification of C–S–H, and, for the first time, to possibly distinguish the contributions of inner and outer product C–S–H to the small angle scattering of cement paste. The results indicate that the outer product C–S–H is mainly responsible for the q^?3 regime, whereas the inner product C–S–H transitions to a q^?2 regime. Various hypotheses are discussed to explain these regimes.