Disentangling instrumental broadening

A new procedure aiming at disentangling the instrumental profile broadening and the relevant X-ray powder diffraction (XRPD) profile shape is presented. The technique consists of three steps: denoising by means of wavelet transforms, background suppression by morphological functions and deblurring by a Lucy--Richardson damped deconvolution algorithm. Real XRPD intensity profiles of ceria samples are used to test the performances. Results show the robustness of the method and its capability of efficiently disentangling the instrumental broadening affecting the measurement of the intrinsic physical line profile. These features make the whole procedure an interesting and user-friendly tool for the pre-processing of XRPD data.Comment: 9 pages, 1 table, 1 figure; typos correcte

Site-occupancy factors in the Debye scattering equation : a theoretical discussion on significance and correctness

The Debye scattering equation (DSE) [Debye (1915). Ann. Phys. 351, 809-823] is widely used for analyzing total scattering data of nanocrystalline materials in reciprocal space. In its modified form (MDSE) [Cervellino et al. (2010). J. Appl. Cryst. 43, 1543-1547], it includes contributions from uncorrelated thermal agitation terms and, for defective crystalline nanoparticles (NPs), average site-occupancy factors (s.o.f.'s). The s.o.f.'s were introduced heuristically and no theoretical demonstration was provided. This paper presents in detail such a demonstration, corrects a glitch present in the original MDSE, and discusses the s.o.f.'s physical significance. Three new MDSE expressions are given that refer to distinct defective NP ensembles characterized by: (i) vacant sites with uncorrelated constant site-occupancy probability; (ii) vacant sites with a fixed number of randomly distributed atoms; (iii) self-excluding (disordered) positional sites. For all these cases, beneficial aspects and shortcomings of introducing s.o.f.'s as free refinable parameters are demonstrated. The theoretical analysis is supported by numerical simulations performed by comparing the corrected MDSE profiles and the ones based on atomistic modeling of a large number of NPs, satisfying the structural conditions described in (i)-(iii)

Reducing Nitrogen Dosage in Triticum durum Plants with Urea-Doped Nanofertilizers

Nanotechnology is emerging as a very promising tool towards more efficient and sustainable practices in agriculture. In this work, we propose the use of non-toxic calcium phosphate nanoparticles doped with urea (U-ACP) for the fertilization of Triticum durum plants. U-ACP nanoparticles present very similar morphology, structure, and composition than the amorphous precursor of bone mineral, but contain a considerable amount of nitrogen as adsorbed urea (up to ca. 6 wt % urea). Tests on Triticum durum plants indicated that yields and quality of the crops treated with the nanoparticles at reduced nitrogen dosages (by 40%) were unaltered in comparison to positive control plants, which were given the minimum N dosages to obtain the highest values of yield and quality in fields. In addition, optical microscopy inspections showed that Alizarin Red S stained nanoparticles were able to penetrate through the epidermis of the roots or the stomata of the leaves. We observed that the uptake through the roots occurs much faster than through the leaves (1 h vs. 2 days, respectively). Our results highlight the potential of engineering nanoparticles to provide a considerable efficiency of nitrogen uptake by durum wheat and open the door to design more sustainable practices for the fertilization of wheat in fields.This research was funded by Fondazione CARIPLO (project no. 2016-0648: Romancing the stone: size-controlled HYdroxyaPATItes for sustainable Agriculture–HYPATIA) and the Spanish Ministerio de Ciencia, Innovación y Universidades (MCIU/AEI/FEDER) with the Projects NanoSmart (RYC-2016-21042) and NanoVIT (RTI-2018-095794-A-C22). GBRR also acknowledges the Spanish MICINN for her postdoctoral contract within the Juan de la Cierva Program (JdC-2017)

Macromolecular Fingerprinting of Sulfolobus Species in Biofilm: A Transcriptomic and Proteomic Approach Combined with Spectroscopic Analysis

Microorganisms in nature often live in surfaceassociated sessile communities, encased in a self-produced matrix, referred to as biofilms. Biofilms have been well studied in bacteria but in a limited way for archaea. We have recently characterized biofilm formation in three closely related hyperthermophilic crenarchaeotes: Sulfolobus acidocaldarius, S. solfataricus, and S. tokodaii. These strains form different communities ranging from simple carpet structures in S. solfataricus to high density tower-like structures in S. acidocaldarius under static condition. Here, we combine spectroscopic, proteomic, and transcriptomic analyses to describe physiological and regulatory features associated with biofilms. Spectroscopic analysis reveals that in comparison to planktonic life-style, biofilm life-style has distinctive influence on the physiology of each Sulfolobus spp. Proteomic and transcriptomic data show that biofilm-forming life-style is strain specific (eg ca. 15% of the S. acidocaldarius genes were differently expressed, S. solfataricus and S. tokodaii had ∼3.4 and ∼1%, respectively). The -omic data showed that regulated ORFs were widely distributed in basic cellular functions, including surface modifications. Several regulated genes are common to biofilm-forming cells in all three species. One of the most striking common response genes include putative Lrs14-like transcriptional regulators, indicating their possible roles as a key regulatory factor in biofilm development

Implementation of a distribution state estimation algorithm on a low voltage test facility with distributed energy resources

The paper illustrates the development and the implementation of a Distribution State Estimation (DSE) algorithm for the Low Voltage Test Facility with Distributed Energy Resources of the Italian Research center RSE. The algorithm is integrated into a Distribution Management System within the control system of the Test Site organized as a microgrid. The Test Facility is equipped with conventional and renewable generation plants, storage systems and programmable loads. Switching boxes allow to obtain a very high number of different topology configurations. The paper shows details of the methodologies and theoretical bases adopted for the algorithm design, implementation and testing of a two level state estimation procedure. Simulation and comparison with field results allow the evaluation of the power contributions to total nodal injections, in all the possible grid configurations