bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhancing the photostability and bioaccessibility of resveratrol using ovalbumin–carboxymethylcellulose nanocomplexes and nanoparticles
Authors: Xiong Wenfei , Ren Cong , Li Jing , Li Bin
Published: May 2018

The objective of this study was to investigate the impact of encapsulating resveratrol in ovalbumin (OVA)–carboxymethylcellulose (CMC) nanocomplexes or nanoparticles on its photostability and bioaccessibility.
Development of pharmaceutically relevant bio-based intermediates though aldol condensation and Claisen–Schmidt reactions of dihydrolevoglucosenone (Cyrene®)
Authors: Hughes Liam , McElroy Con R. , Whitwood Adrian C. , Hunt Andrew J.
Published: May 2018

Dihydrolevoglucosenone (Cyrene®) has been successfully utilised as a bio-based platform molecule for the synthesis of pharmaceutically relevant intermediates through aldol condensation reactions.
Highly dispersed, ultra-small and noble metal-free Cu nanodots supported on porous SiO2 and their excellent catalytic hydrogenation of dimethyl oxalate to methyl glycolate
Authors: Abbas Mohamed , Chen Zheng , Zhang Juan , Chen Jiangang
Published: May 2018

Noble metal-free ultra-small and highly dispersed Cu/SiO2 catalyst with high Cu+/(Cu+ + Cu0) ratio synthesized by novel and rapid sonochemical method displayed excellent MG selectivity.
Ecology and evolution of metabolic cross-feeding interactions in bacteria
Authors: D'Souza Glen , Shitut Shraddha , Preussger Daniel , Yousif Ghada , Waschina Silvio , Kost Christian
Published: May 2018

The causes and consequences of bacterial metabolic cross-feeding mutualisms.
Quantum dots cause acute systemic toxicity in lactating rats and growth restriction of offspring
Authors: Yang Lin , Kuang Huijuan , Zhang Wanyi , Wei Hua , Xu Hengyi
Published: May 2018

QDs induced systemic injuries to dams in a dose-dependent and reversible manner and retarded the offspring growth.
Inherent electrochemistry and charge transfer properties of few-layered two-dimensional Ti3C2TxMXene
Authors: Nayak Pranati , Jiang Qiu , Mohanraman Rajeshkumar , Anjum Dalaver , Hedhili Mohamed Nejib , Alshareef Husam N.
Published: May 2018

Few-layered Ti3C2TxMXene undergoes more electro-oxidation in positive potential window and aqueous medium compared to a multi-layered and bulk 3D stack of Ti3C2Txlayers.
Versatile porous graphene flakes derived from alkali metal carbonates using an ultrafast and sulfuric acid-free solid-state oxidation reaction
Authors: Yoon Yeoheung , Lee Minhe , Kim Seong Ku , Song Wooseok , Myung Sung , Lim Jongsun , Zyung Taehyoung , Lee Sun Sook , An Ki-Seok
Published: May 2018

We report a H2SO4-free, alkali metal carbonate (M2CO3) based solid-state reaction, which offers an ultra-fast, effective method for the synthesis of single-layered graphene oxide (GO).
Cobalt-assisted recrystallization and alignment of pure and doped graphene
Authors: Usachov Dmitry Yu. , Bokai Kirill A. , Marchenko Dmitry E. , Fedorov Alexander V. , Shevelev Viktor O. , Vilkov Oleg Yu. , Kataev Elmar Yu. , Yashina Lada V. , Rühl Eckart , Laubschat Clemens , Vyalikh Denis V.
Published: May 2018

We convert polycrystalline graphene into monocrystalline graphene, and explore the kinetics of two-dimensional recrystallization as well as the underlying mechanism.
The synthesis of multi-substituted pyrrolidinones via a direct [3 + 2] cycloaddition of azaoxyallyl cations with aromatic ethylenes
Authors: Zhang Yixin , Ma Haojie , Liu Xingxing , Cui Xinfeng , Wang Shaohua , Zhan Zhenzhen , Pu Jinghong , Huang Guosheng
Published: May 2018

A novel [3 + 2] cycloaddition reaction of azaoxyallyl cations and aromatic ethylenes has been developed to afford multi-substituted pyrrolidinones in moderate to good yields.
Pd(ii)–NHC coordination-driven formation of water-soluble catalytically active single chain nanoparticles
Authors: Lambert Romain , Wirotius Anne-Laure , Garmendia Sofiem , Berto Pierre , Vignolle Joan , Taton Daniel
Published: May 2018

Intramolecular coordination of a linear copolymer precursor yields single chain nanoparticles (SCNP's) consisting of Pd(ii)-NHC2 crosslinks and showing a beneficial SCNP effect when used for the Suzuki coupling in water.
Nucleophile-initiated anionic polymerization of zwitterionic monomers derived from vinylpyridines in aqueous media under ambient aerobic conditions
Authors: Jana Satyasankar , Klähn Marco , Parthiban Anbanandam
Published: May 2018

Anionic polymerization of vinylpyridine based zwitterionic monomers using nucleophile initiators under natural conditions and DFT calculations for such polymerization are reported here.
Pickering miniemulsion polymerization using graphene oxide: effect of addition of a conventional surfactant
Authors: Fadil Yasemin , Jasinski Florent , Wing Guok Tien , Thickett Stuart C. , Minami Hideto , Zetterlund Per B.
Published: May 2018

Polystyrene/graphene oxide (PSt/GO) nanocomposite latexes have been prepared by Pickering miniemulsion polymerization in the presence of the conventional surfactant sodium dodecyl sulfate (SDS) in order to investigate its influence on the polymerization mechanism.
Graphitic-phase carbon nitride-based electrochemiluminescence sensing analyses: recent advances and perspectives
Authors: Jiang Jingjing , Lin Xinyi , Ding Dong , Diao Guowang
Published: May 2018

This review describes the current trends in synthesis methods, signaling strategies, and sensing applications of g-C3N4-based ECL emitters.
Fe3O4 nanoclusters highly dispersed on a porous graphene support as an additive for improving the hydrogen storage properties of LiBH4
Authors: Xu Guang , Zhang Wei , Zhang Ying , Zhao Xiaoxia , Wen Ping , Ma Di
Published: May 2018

Fe3O4 nanoclusters highly dispersed on a porous graphene support were fabricated and significantly improved the dehydrogenation kinetics and rehydrogenation reversibility of LiBH4.
Density functional theory investigation on iridium(iii) complexes for efficient blue electrophosphorescence
Authors: Zhang Jian-Po , Wang Ying , Ma Jian-Bo , Jin Li , Liu Fang-Tong , Bai Fu-Quan
Published: May 2018

The geometrical structures, electronic structures, optoelectronic properties and phosphorescence efficiencies of blue-emitting phosphors [Ir(fpmi)2(pyim)], [Ir(pyim)2(fpmi)], [Ir(fpmi)2(fptz)], [Ir(fpmi)2(pypz)] and [Ir(tfmppz)2(pyim)]), were investigated by DFT and TDDFT methods.
Synthesis, aggregation induced emission and through space conjugation of triphenylvinylphenyl substituted [2.2]paracyclophane-1,9-diene
Authors: Yu Chin-Yang , Lai Yu-Chun
Published: May 2018

A highly ring-strained molecule, 4-triphenylvinylphenyl-[2.2]paracyclophane-1,9-diene, with aggregation-induced emission and through space conjugation was successfully synthesized.
Thermal conductivity of poly(3,4-ethylenedioxythiophene) films engineered by oxidative chemical vapor deposition (oCVD)
Authors: Smith Phil M. , Su Laisuo , Gong Wei , Nakamura Nathan , Reeja-Jayan B. , Shen Sheng
Published: May 2018

Measuring the thermal conductivity of oxidative chemical vapor deposited poly(3,4-ethylenedioxythiophene) thin films.
Total chemical synthesis and biophysical properties of a designed soluble 24 kDa amyloid analogue
Authors: Boehringer Régis , Kieffer Bruno , Torbeev Vladimir
Published: May 2018

A soluble amyloid analogue was designed and prepared by total chemical synthesis using native chemical ligation.
Tunable syngas production from photocatalytic CO2 reduction with mitigated charge recombination driven by spatially separated cocatalysts
Authors: Li Ang , Wang Tuo , Chang Xiaoxia , Zhao Zhi-Jian , Li Chengcheng , Huang Zhiqi , Yang Piaoping , Zhou Guangye , Gong Jinlong
Published: May 2018

This paper describes the production of syngas from photocatalytic CO2 reduction with a tunable CO/H2 ratio via adjusting the properties of CuPt alloy and the distribution of cocatalysts on TiO2 hollow spheres.
Correction: Rapid access to diverse, trifluoromethyl-substituted alkenes using complementary strategies
Authors: Phelan James P. , Wiles Rebecca J. , Lang Simon B. , Kelly Christopher B. , Molander Gary A.
Published: May 2018

Correction for ‘Rapid access to diverse, trifluoromethyl-substituted alkenes using complementary strategies’ by James P. Phelan et al., Chem. Sci., 2018, 9, 3215–3220.
An attraction–repulsion transition of force on wedges induced by active particles
Authors: Hua Yunfeng , Li Ke , Zhou Xiaolin , He Linli , Zhang Linxi
Published: May 2018

For two anti-parallel wedges in an active bath, a transition from long-range repulsion to long-range attraction occurs by varying the apex angle. For two parallel wedges, the effective force experiences a transition from oscillating repulsion to attraction as the wedge-to-wedge distance increases.
Branching and alignment in reverse worm-like micelles studied with simultaneous dielectric spectroscopy and RheoSANS
Authors: Riley John K. , Richards Jeffrey J. , Wagner Norman J. , Butler Paul D.
Published: May 2018

The breaking of micellar connections in branched wormlike micelles under shear is resolved for the first time.
A first-principles study of the effects of electron–phonon coupling on the thermoelectric properties: a case study of the SiGe compound
Authors: Fan D. D. , Liu H. J. , Cheng L. , Liang J. H. , Jiang P. H.
Published: May 2018

The lattice thermal conductivity of the SiGe compound can be significantly reduced by electron–phonon coupling at higher carrier concentration, which in turn obviously enhances its thermoelectric figure-of-merit.
In situ formation of porous graphitic carbon wrapped MnO/Ni microsphere networks as binder-free anodes for high-performance lithium-ion batteries
Authors: Kong Xiangzhong , Pan Anqiang , Wang Yaping , Selvakumaran Dinesh , Lin Jiande , Cao Xinxin , Liang Shuquan , Cao Guozhong
Published: May 2018

Porous graphitic carbon wrapped MnO/Ni microsphere networks exhibit excellent electrochemical performances when used as binder-free anodes for LIBs.
Me–N–C (Me = Fe, Cu, and Co) nanosheet as a promising charge-controlled CO2 capture material
Authors: Li Xiaofang , Zhu Lei , Chang Xiao , He Daliang , Xue Qingzhong , Xing Wei
Published: May 2018

This figure represents a controlled CO2 adsorption and desorption process on C3N nanosheet by tuning charge state, demonstrating M–C–N nanosheet is a promising candidate for CO2 capture.
Oxide-ion conduction via interstitials in scheelite-type LaNbO4: a first-principles study
Authors: Toyoura Kazuaki , Sakakibara Yusuke , Yokoi Tatsuya , Nakamura Atsutomo , Matsunaga Katsuyuki
Published: May 2018

The interstitial oxide-ion mechanism in scheelite-type lanthanum niobate has theoretically been analyzed using first-principles calculations.
Hyperactive iron carbide@N-doped reduced graphene oxide/carbon nanotube hybrid architecture for rapid CO hydrogenation
Authors: Park Beum Jin , Jang Sanha , Lee Jin Hee , Chun Dong Hyun , Park Ji Chan , Park Ho Seok
Published: May 2018

Fe5C2@Ns-rGO/CNT was prepared and applied to a rapid CO hydrogenation reaction, showing high activity under high gas velocity. The performance was attributed to high surface area, 3D-interconnected pores, apt for fast mass transport, and N-doped enhancing the catalytic activity.
Porous NiMoO4−x/MoO2 hybrids as highly effective electrocatalysts for the water splitting reaction
Authors: Zhang Zhe , Ma Xingxing , Tang Jilin
Published: May 2018

NiMoO4−x/MoO2 hybrids with highly active Mo5+ species and atomic-level coupled nanointerfaces were synthesized as highly effective electrocatalysts for the water splitting reaction.
P3-type K0.32Fe0.35Mn0.65O2·0.39H2O: a promising cathode for Na-ion full batteries
Authors: Wang Sai , Zhu Yun-hai , Yan Jun-min , Zhang Xin-bo
Published: May 2018

P3-type K0.32Fe0.35Mn0.65O2·0.39H2O consisting of environmentally friendly and low cost elements is first proposed and demonstrated to be a promising cathode for Na-ion full batteries.
Alkali-stable partially fluorinated poly(arylene ether) anion exchange membranes with a claw-type head for fuel cells
Authors: Wang Xiu Qin , Lin Chen Xiao , Liu Fang Hua , Li Ling , Yang Qian , Zhang Qiu Gen , Zhu Ai Mei , Liu Qing Lin
Published: May 2018

A claw-type configuration is responsible for a distinct microphase-separated structure.
Spinel photocatalysts for environmental remediation, hydrogen generation, CO2 reduction and photoelectrochemical water splitting
Authors: Chandrasekaran Sundaram , Bowen Chris , Zhang Peixin , Li Zheling , Yuan Qiuhua , Ren Xiangzhong , Deng Libo
Published: May 2018

The fundamental aspects, photocatalytic applications and ways to enhance the performance of spinels are systematically reviewed in this paper.
Selective gas diffusion in two-dimensional MXene lamellar membranes: insights from molecular dynamics simulations
Authors: Li Libo , Zhang Tao , Duan Yifan , Wei Yanying , Dong Chaojie , Ding Li , Qiao Zhiwei , Wang Haihui
Published: May 2018

The selective gas diffusion in MXene membranes was exploredviamolecular simulations, yielding insights for developing highly efficient gas separation membranes.
Determining ideal strength and failure mechanism of thermoelectric CuInTe2 through quantum mechanics
Authors: Li Guodong , An Qi , Morozov Sergey I. , Duan Bo , Zhai Pengcheng , Zhang Qingjie , Goddard III William A. , Snyder G. Jeffrey
Published: May 2018

We applied quantum mechanics to determine the intrinsic mechanical properties of CuInTe2 under pure shear, uniaxial tension, and biaxial shear deformations.
Advances in luminescent materials with aggregation-induced emission (AIE) properties for biomedical applications
Authors: Wang Haibo , Liu Gongyan
Published: May 2018

Fluorescent materials with AIE effect have recently received great attention in biomedical research because of their good optical properties, species diversity and high sensitivity.
Crystal-phase control of GaAs–GaAsSb core–shell/axial nanowire heterostructures by a two-step growth method
Authors: Zhou Chen , Zheng Kun , Chen Ping-Ping , Matsumura Syo , Lu Wei , Zou Jin
Published: May 2018

This study provides a controllable approach to grow both wurtzite and zinc-blende III–Sb nanowire heterostructures.
Highly chemiluminescent silver nanoclusters with a dual catalytic center
Authors: Zhao Kun , Shen Wen , Cui Hua
Published: May 2018

Highly chemiluminescent silver nanoclusters with a dual catalytic center have been synthesized via a facile one-pot strategy.
Recent advances in the detection of brown adipose tissue in adult humans: a review
Authors: Ong Frank J. , Ahmed Basma A. , Oreskovich Stephan M. , Blondin Denis P. , Haq Tahniyah , Konyer Norman B. , Noseworthy Michael D. , Haman Francois , Carpentier Andre C. , Morrison Katherine M. , Steinberg Gregory R.
Published: May 2018

The activation of brown adipose tissue (BAT) is associated with reductions in circulating lipids and glucose in rodents and contributes to energy expenditure in humans indicating the potential therapeutic importance of targetting this tissue for the treatment of a variety of metabolic disorders. In order to evaluate the therapeutic potential of human BAT, a variety of methodologies for assessing the volume and metabolic activity of BAT are utilized. Cold exposure is often utilized to increase BAT activity but inconsistencies in the characteristics of the exposure protocols make it challenging to compare findings. The metabolic activity of BAT in response to cold exposure has most commonly been measured by static positron emission tomography of 18F-fluorodeoxyglucose in combination with computed tomography (18F-FDG PET-CT) imaging, but recent studies suggest that under some conditions this may not always reflect BAT thermogenic activity. Therefore, recent studies have used alternative positron emission tomography and computed tomography (PET-CT) imaging strategies and radiotracers that may offer important insights. In addition to PET-CT, there are numerous emerging techniques that may have utility for assessing BAT metabolic activity including magnetic resonance imaging (MRI), skin temperature measurements, near-infrared spectroscopy (NIRS) and contrast ultrasound (CU). In this review, we discuss and critically evaluate the various methodologies used to measure BAT metabolic activity in humans and provide a contemporary assessment of protocols which may be useful in interpreting research findings and guiding the development of future studies.
Intensive Auditory Comprehension Treatment for Severe Aphasia: A Feasibility Study
Authors: Knollman-Porter Kelly , Dietz Aimee , Dahlem Kelly
Published: May 2018

Background

Severe auditory comprehension impairments secondary to aphasia can adversely influence rehabilitative outcomes and quality of life. Studies examining intensive rehabilitative treatments for severe single-word auditory comprehension impairments are needed.

Objectives

Our purpose was to examine the feasibility and influence of a high-intensity word–picture verification treatment on high-frequency, word response accuracy. Research questions: (a) Can people with severe aphasia tolerate an intensive comprehension treatment? (b) Does an intensive intervention increase auditory comprehension response accuracy of spoken high-frequency words?

Method

This single-case ABA design study included 2 participants with chronic, severe auditory comprehension deficits secondary to stroke. A high-frequency, word–picture verification treatment was administered 2 hr/day, 5 days/week for 4 weeks and required participants to match the spoken word of the examiner to a picture representing an object.

Results

Preliminary results suggest that some people with severe chronic aphasia can tolerate an intensive auditory comprehension treatment and demonstrate improvements in high-frequency, word-level response accuracy with large effect sizes suggesting generalization to untrained stimuli.

Conclusions

An intensive auditory comprehension treatment protocol can contribute to improvements in response accuracy for some people with severe aphasia. Larger sample size studies are needed to further examine the influence of intensity on improvements in auditory comprehension.
Incoherent clocking in coherent radio interferometers
Authors: Carlson B.R.
Published: May 2018

Radio interferometer arrays are instruments requiring real‐time synchronisation of all array elements to capture and align the observed source wavefront prior to further processing such as correlation and/or beamforming. One method is to deliver a frequency, from a common central local oscillator (LO), using a round‐trip phase‐stable distribution system such that each element has its own phase‐stable copy of the clock with required real‐time fidelity for down‐conversion and digitisation. The method described here involves equipping each array element with its own independent ‘eLO’ and sending a ‘tracer’ of it to a central site, where the difference between the elements’ eLOs and the central ‘cLO’ is measured. The digitised data from each element is corrected at the central site according to the measurement, before correlation/beamforming. The advantage of this method is that only a ‘trace’ of eLO, needed to measure the rate of change of eLO relative to cLO integrated over a measurement interval, needs to be conveyed over this tracer link, rather than the frequency itself, thereby requiring lower link temporal fidelity and bandwidth.
Multi‐stage filtering for single rainy image enhancement
Authors: Shi Zhenghao , Li Yaowei , Zhao Minghua , Feng Yaning , He Lifeng
Published: May 2018

Rain image enhancement is important for outdoor computer vision applications. In this study, the authors propose a multi‐stage filtering method for single rainy image enhancement. It is based on their new rainy image model, and consists of two main operations: rain streaks removal and rain fog removal. For rain streaks removal, based on one key observation that the low‐pass version of a rainy image and that of a non‐rainy image of the same scene are almost the same after appropriate low‐pass filtering, they remove rain streaks from rainy images by decomposing an input rainy image (or a rainy component image) into the low‐frequency (LF) part and the high‐frequency (HF) part via an LF smooth filter, i.e. the traditional Gaussian filter with a simple subtraction operation in multiple different stages. After rain streaks removal, dark channel prior‐based method was employed for rain fog removal. Experimental results show that the proposed algorithm generated comparable outputs with most of the state‐of‐the‐art algorithms with low computation cost.
Non‐subsampled shearlet transform based MRI and PET brain image fusion using simplified pulse coupled neural network and weight local features in YIQ colour space
Authors: Ouerghi Hajer , Mourali Olfa , Zagrouba Ezzeddine
Published: May 2018

Magnetic resonance imaging (MRI) and positron emission tomography (PET) image fusion is a recent hybrid modality used in several oncology applications. The MRI image shows the brain tissue anatomy and does not contain any functional information, while the PET image indicates the brain function and has a low spatial resolution. A perfect MRI–PET fusion method preserves the functional information of the PET image and adds spatial characteristics of the MRI image with the less possible spatial distortion. In this context, the authors propose an efficient MRI–PET image fusion approach based on non‐subsampled shearlet transform (NSST) and simplified pulse‐coupled neural network model (S‐PCNN). First, the PET image is transformed to YIQ independent components. Then, the source registered MRI image and the Y‐component of PET image are decomposed into low‐frequency (LF) and high‐frequency (HF) subbands using NSST. LF coefficients are fused using weight region standard deviation (SD) and local energy, while HF coefficients are combined based on S‐PCCN which is motivated by an adaptive‐linking strength coefficient. Finally, inverse NSST and inverse YIQ are applied to get the fused image. Experimental results demonstrate that the proposed method has a better performance than other current approaches in terms of fusion mutual information, entropy, SD, fusion quality, and spatial frequency.
DC–DC buck converter solely powered by supercapacitors for efficiently powering the hand‐held devices
Authors: Sengupta Aditya Sankar , Mohanty Saraju P. , Bhattacharyya Bidyut K.
Published: May 2018

In this study, a closed loop feed‐forward direct current (DC)–DC converter has been designed which operates solely on two supercapacitor modules. This is an innovative new design where the challenge was to maintain the constant output voltage when the input voltage of the converter is decaying continuously as a function of time as long as the output load draws current. The second innovation is the selection of all the components that are required to design the regulated output DC–DC converter, even though the parameters like the supply voltages for the components have been falling continuously as a function of time since the supercapacitor modules are providing these supply voltages. The design is also robust enough to withstand certain fluctuations in the output current ranging between 200 and 950 mA and yet maintain a regulated output voltage. In this study, the authors have successfully demonstrated that one can design a DC–DC converter powered by supercapacitors to generate a constant voltage and desired output current while all the components required making that DC–DC converter remain operational although the input voltage of the supercapacitors is dropping constantly, due to the output drawing current. The operating frequency, i.e. the switching frequency ranges from 1.5 to 3.5 kHz.
New database for a sample of optically bright lensed quasars in the northern hemisphere
Authors: Gil-Merino R. , Goicoechea L. J. , Shalyapin V. N. , Oscoz A.
Published: May 2018

In the framework of the Gravitational LENses and DArk MAtter (GLENDAMA) project, we present a database of nine gravitationally lensed quasars (GLQs) that have two or four images brighter thanr= 20 mag and are located in the northern hemisphere. This new database consists of a rich variety of follow-up observations included in the GLENDAMA global archive, which is publicly available online and contains 6557 processed astronomical frames of the nine lens systems over the period 1999−2016. In addition to the GLQs, our archive also incorporates binary quasars, accretion-dominated radio-loud quasars, and other objects, where about 50% of the non-GLQs were observed as part of a campaign to identify GLQ candidates. Most observations of GLQs correspond to an ongoing long-term macro-programme with 2−10 m telescopes at the Roque de los Muchachos Observatory, and these data provide information on the distribution of dark matter at all scales. We outline some previous results from the database, and we additionally obtain new results for several GLQs that update the potential of the tool for astrophysical studies.
Radio jets and gamma-ray emission in radio-silent narrow-line Seyfert 1 galaxies
Authors: Lähteenmäki A. , Järvelä E. , Ramakrishnan V. , Tornikoski M. , Tammi J. , Vera R. J. C. , Chamani W.
Published: May 2018

We have detected six narrow-line Seyfert 1 (NLS1) galaxies at 37 GHz that were previously classified as radio silent and two that were classified as radio quiet. These detections reveal the presumption that NLS1 galaxies labelled radio quiet or radio silent and hosted by spiral galaxies are unable to launch jets to be incorrect. The detections are a plausible indicator of the presence of a powerful, most likely relativistic jet because this intensity of emission at 37 GHz cannot be explained by, for example, radiation from supernova remnants. Additionally, one of the detected NLS1 galaxies is a newly discovered source of gamma rays and three others are candidates for future detections.
Diagnosis of the Ghiss Nekor aquifer in order to elaborate the aquifer contract
Authors: Baite Wissal , Boukdir A. , Zitouni A. , Dahbi S. D. , Mesmoudi H. , Elissami A. , Sabri E. , Ikhmerdi H.
Published: May 2018

The Ghiss-Nekor aquifer, located in the north-east of the action area of the ABHL, plays a strategic role in the drinkable water supply of the city of Al Hoceima and of the neighboring urban areas. It also participates in the irrigation of PMH. However, this aquifer has problems such as over-exploitation and pollution. In the face of these problems, the only Solution is the establishment of a new mode of governance, which privileges the participation, the involvement and the responsibility of the actors concerned in a negotiated contractual framework, namely the aquifer contract. The purpose of this study is to diagnose the current state of the Ghiss Nekor aquifer, the hydrogeological characterization of the aquifer, the use of the waters of the aquifer, the Problem identification and the introduction of the aquifer contract, which aims at the participatory and sustainable management of underground water resources in the Ghiss- Nekor plain, to ensure sustainable development.
Theoretical study of the dissolution kinetics of galena and cerussite in an abandoned mining area (Zaida mine, Morocco)
Authors: El Alaoui Lamiae , Dekayir Abdelilah
Published: May 2018

In the abandoned mine in Zaida, the pit lakes filled with water constitute significant water reserves. In these lakes, the waters are permanently in contact with ore deposit (cerussite and galena). The modelling of the interaction of waters with this mineralization shows that cerussite dissolves more rapidly than galena. This dissolution is controlled by the pH and dissolved oxygen concentration in solution. The lead concentrations recorded in these lakes come largely from the dissolution of cerussite.
Impact of wastewater from the rural commune of Jmaa Moulblad on the physico-chemical quality of the waters of the Grou River (Rabat region, Morocco)
Authors: Arifi Karim , Tahri Latifa , El Abid Abdallah , Hefiane Fatima Zahra , Elblidi Souad , Yahyaoui Ahmed , Fekhaoui Mohammed
Published: May 2018

The Grou River is one of the main rivers that feed the reservoir of the Sidi Mohammed Ben Abdellah (SMBA) dam in Morocco. However, this river is particularly threatened by the pollution problem. It is in this context that this study aims to study the effect of wastewater from the rural commune of Jmaa Moulblad on the physicochemical quality of the waters of this river. We analyzed 11 physicochemical parameters (T° of area, T° of water, pH, EC, mV, Sal, TDS, BOD, COD, SS and TOC), with a monthly frequency since the month of December 2014 until November 2015. The results obtained show a worrying situation of the state of this watercourse. To remedy this problem, we recommend pre-treatment of wastewater before discharge and the implementation of a management plan and sustainable management of the Grou River watershed.
Adsorption of Cr (III) from aqueous solution by two forms of a superabsorbant polymer : parametric study and effect of activation mode
Authors: Ouass A. , Essaadaoui Y. , Kadiri L. , Lebkiri I. , Lafreme C. , Cherkaoui M. , Lebkiri A. , Rifi E. H.
Published: May 2018

The adsorption of chromium ions Cr3+ using two forms of a superabsorbant polymer PANa from aqueous solution was investigated. On one hand the equilibrium pH with the distilled water and the pH of point of zero charge have been studied in order to characterize the acid-base behavior of both of PANa forms. On the other hand, the effect of contact time between PANa and the metallic solution and stirring speed of aqueous solution on the adsorption rate were established to highlight the importance of PANa as an efficient adsorbent of chromium ions Cr3+.
Characterization of pyrolysis products derived from three biological wastes and their effect on plant growth and soil water retention
Authors: Bouqbis Laila , Werner Koyro Hans , Kammann Claudia , Zohra Ainlhout Lalla Fatima , Boukhalef Laila , Cherif Harrouni Moulay
Published: May 2018

Over two-thirds of Morocco can be classified as semiarid, arid and desert with low and variable rainfalls. While the country is subject to frequent drought, groundwater resources are predominantly consume by irrigated agriculture leading to the depletion of water resources and degradation of soil quality. Application of bio-resources wastes to soils after pyrolysis process is well documented to help retain water and nutrients in soils. In this study, three bio-resources wastes derived from argan shells, wood chip, a blend of paper sludge and wheat husks are characterized for physical and chemical properties. To determine the potential impact of salt stress and toxic substances the second part of this study focused on the effect these bio-resources wastes have on germination of salad and barley respectively. The three bio-resources obtained from different biomass showed some unique properties compared to the soil, such as high electrical conductivity (EC), high content of K, Na and Mg, low content of heavy metals. Moreover, the water holding capacities increased with increasing application of bio-resources wastes. Concerning the phytotoxic tests, no negative effect was observed neither for salad (Lactuca sativa L.) nor for barley (Hordeum vulgare) indicating that the three bio-resources could be safely used for agriculture. Collectively, the use of these bio-resources wastes as a soil amendment is anticipated to increase both water and nutrient and could provide the potential for a better plant growth mainly in semiarid, arid and desert climatic conditions like the case of Morocco in which the agricultural practices reserve a majority of the water resources to be used for irrigation.
Kinetic studies of adsorption of Cu (II) from aqueous solution by coriander seeds (Coriandrum Sativum)
Authors: Kadiri L. , Lebkiri A. , Rifi E.H. , Ouass A. , Essaadaoui Y. , Lebkiri I. , Hamad H.
Published: May 2018

The adsorption of copper ions Cu2+ by Coriandrum Sativum seeds (CSS) from aqueous solution was studied in order to highlight the importance of coriander seeds as a potential tool in the treatment of wastewaters containing heavy metals. The kinetic studies of adsorption of Cu (II) were discussed using the spectroscopic technique “Inducting Coupled Plasma” (ICP). The effects of initial copper ion concentration and contact time were determined. All results show that coriander seeds have, over their culinary and medicinal benefits, a significant adsorbent power of copper ions.
Hydrological and hydroclimatic regimes in the Ouergha watershed
Authors: Msatef Karim , Benaabidate Lahcen , Bouignane Aziz
Published: May 2018

This work consists in studying the hydrological and hydroclimatic regime of the Ouergha watershed and frequency analysis of extreme flows and extreme rainfall for peak estimation and return periods, in order to prevention and forecasting against risks (flood...). Hydrological regime analysis showed a regime of the rain type, characterized by rainfed abundance with very high winter flows, so strong floods. The annual module and the different coefficients show hydroclimatic fluctuations in relation to a semihumid climate. The water balance has highlighted the importance of the volumes of water conveyed upstream than downstream, thus confirming the morphometric parameters of watershed and the lithological nature. Frequency study of flows and extreme rainfall showed that these flows governed by dissymmetrical laws based on methods Gumbel, GEV, Gamma and Log Pearson III.
Flood risk management in the Souss watershed
Authors: Bouaakkaz Brahim , El Abidine El Morjani Zine , Bouchaou Lhoussaine , Elhimri Hamza
Published: May 2018

Flooding is the most devasting natural hazards that causes more damage throughout the world. In 2016, for the fourth year in a row, it was the most costly natural disaster, in terms of global economic losses: $ 62 billion, according to a Benfield’s 2016 annual report on climate and natural disasters [1]. The semi-arid to arid Souss watershed is vulnerable to floods, whose the intensity is becoming increasingly alarming and this area does not escape to the effects of this extreme event.. Indeed, the susceptibility of this region to this type of hazard is accentuated by its rapid evolution in terms of demography, uncontrolled land use, anthropogenic actions (uncontrolled urbanization, encroachment of the hydraulic public domain, overgrazing, clearing and deforestation).), and physical behavior of the environment (higher slope, impermeable rocks, etc.). It is in this context, that we have developed a strategic plan of action to manage this risk in the Souss basin in order to reduce the human, economic and environmental losses, after the modeling of the flood hazard in the study area, using georeferenced information systems (GIS), satellite remote sensing space and multi-criteria analysis techniques, as well as the history of major floods. This study, which generated the high resolution 30m flood hazard spatial distribution map of with accuracy of 85%, represents a decision tool to identify and prioririze area with high probability of hazard occurrence. It can also serve as a basis for urban evacuation plans for anticipating and preventing flood risk in the region, in order to ovoid any dramatic disaster.
Application of electrical geophysics to the release of water resources, case of Ain Leuh (Morocco)
Authors: Zitouni A. , Boukdir A. , El Fjiji H. , Baite W. , Ekouele Mbaki V.R. , Ben Said H. , Echakraoui Z. , Elissami A. , El Maslouhi M.R.
Published: May 2018

Being seen needs in increasing waters in our contry for fine domestics, manufactures and agricultural, the prospecting of subterranean waters by geologic and hydrogeologic classic method remains inaplicable in the cases of the regions where one does not arrange drillings or polls (soundings) of gratitude (recongnition) in very sufficient (self-important) number.

In that case of figure, the method of prospecting geophysics such as the method of nuclear magnetic resonance (NMR) and the method of the geophysics radar are usually used most usually because they showed, worldwide, results very desive in the projects of prospecting and evaluation of the resources in subterranean waters.

In the present work, which concerns only the methodology of the electric resistivity, we treat the adopted methodological approach and the study of the case of application in the tray of Ajdir Ain Leuh.
Application of the Electrical (Geophysical) Method for the Identification of the Sealed Bevel in the Coastal Region of Walidia Province of el Jadida – Morocco
Authors: Elfjiji H. , Boukdir A. , Zitouni A.
Published: May 2018

The Walidia area knows a great development of agricultural, industrial, maritime activities and a very great demographic expansion. This development is accompanied by a growing demand for water. On the other hand, any intense abstraction of fresh water at a coastal aquifer capture field causes a decrease in groundwater flow and a lowering of the piezometric surface. There is therefore a danger of advancing towards the land of the saltwater bevel and salinization of groundwater which is gradually loaded into mineral salts and can reach abnormally high levels.

This work deals with the application of geophysics by electrical sounding method to the in-depth study of the freshwater-salt water interface (salted bevel) on the one hand and the study of the lateral and vertical evolution of the geometry of the different aquifers.

The principle of the method is, when performing an electrical survey, to research how varies, at a given point on the surface, the resistivity of the subsoil vertically. For this one executes in a same place a succession of measurements, increasing each time the dimensions of the device and thus the depth of investigation which is proportional to them. At this site, we explore a slice of ground increasingly thick and thus highlights the changes in geological constitution along the vertical.

The electrical soundings were carried out with the classic Schlumberger device.

The interpretation and the exploitation of the data of the electric soundings carried out made it possible to :

Follow the evolution of the salted bevel roof,

Draw the upstream limit (marine invasion) of salted bevel Hauterivian, on the one hand, and Valanginian and Jurassic on the other hand,

Follow the roof structure of Dridrat limestone (Hauterivien) and limestones of Valanginien and Upper Jurassic,

Draw the map of the marl roof of Safi (Hauterivian) constituting the impermeable substratum of Dridrat limestones.
Influence of as-built surface on fatigue strength and notch sensitivity of Ti6Al4V alloy produced by DMLS
Authors: Nicoletto Gianni , Konečná Radomila , Kunz Ludvík , Frkáň Martin
Published: May 2018

Direct Metal Laser Sintering (DMLS) is one of the additive manufacturing technologies involving a metal powder bed and a laser source to obtain components of complex geometry. The fatigue life of an as-built DMLS part is negatively influenced by the rough surface compared to a machined surface. Since most DMLS components are expected to have also stress concentrations, here the combined effect on fatigue of a as-built surface and a geometrical notch in as-built DMLS Ti6Al4V was investigated using a new test methodology. Miniature specimens having three different directions with respect to build direction were fabricated and tested determining the directional fatigue notch sensitivity of as-built DMLS Ti6Al4V Optical inspection of notch surface quality and roughness measurements demonstrated a ranking of the directional notches that inversely correlated to the measured fatigue performance. The link among the curved surface orientation, the peculiar layer-wise additive manufacturing fabrication and the fatigue notch sensitivity is clarified.
Determination of the anisotropic fatigue behaviour of additively manufactured structures with short-time procedure PhyBaLLIT
Authors: Blinn Bastian , Klein Marcus , Beck Tilmann
Published: May 2018

Additive Manufacturing techniques provide completely new possibilities in component design and creation of innovative material structures. To utilize the whole potential of Additive Manufacturing, the microstructure, the mechanical properties and their interrelations as well as their relationship to the Additive Manufacturing process parameters are essential. Investigations of the fatigue behaviour of additively manufactured (AM-) metallic materials are still available in limited extent. However, as a prerequisite for efficient and reliable use of AM-components in safety relevant structures, sound knowledge of fatigue behaviour and properties of these structures is indispensable. A central aspect in Additive Manufacturing is the anisotropic mechanical behaviour under monotonic and cyclic loading in dependency on the building direction [1, 2]. In the present work, the microstructure and mechanical properties of Selective Laser Melted (SLM) as well as Laser Deposition Welded (LDW) AISI 316L stainless steel specimens are investigated with special focus on the influence of the building direction. The investigated specimens are built in horizontal and vertical direction, resulting in layer planes oriented parallel and perpendicular to the loading direction, respectively. The fatigue tests have been performed on a servohydraulic testing system with measurement of stress-strain-hysteresis as well as of plastic deformation induced changes in temperature and specific electrical resistance. S-Nf-curves in the HCF-regime of AM-specimens have been determined with the time and material efficient Physically Based Lifetime calculation procedure PhyBaLLIT [3]. Anisotropic fatigue behaviour of the different AM-specimens has been rated with load increase tests (LIT) and the usage of S-Nfcurves calculated by the PhyBaLLIT method.
Influence of porosity on the fatigue behaviour of additively fabricated TA6V alloys
Authors: Le Viet-Duc , Pessard Etienne , Morel Franck , Edy François
Published: May 2018

This work is focused on the influence of porosity when dealing with the fatigue behaviour of the TA6V alloys fabricated by the selective laser melting (SLM) process. The presence of porosity is one of the major issue facing additive manufacturing (AM) of metallic components subjected to fatigue loading. In order to study the effect of porosity on the fatigue behaviour, a vast experimental campaign has been undertaken. These materials are fabricated by the SLM process with different building directions (horizontal, vertical and diagonal) thanks to which specimen batches with different pore sizes are obtained. It is observed that despite a low porosity fraction (around 0.01%), the influence of pores on the fatigue strength of the materials is pronounced. A mapping approach is presented, which links the applied stress, the pore size and the fatigue life. This approach makes it possible to accurately characterize the effect of the porosity size, and also to construct Kitagawa-Takahashi diagrams from S-N data.
A Non-Linear Model for Corrosion Fatigue Lifetime Based on Continuum Damage Mechanics
Authors: Zhang Jie , Hertelé Stijn , De Waele Wim
Published: May 2018

Many structures, such as oil platforms and wind turbines, are built in the marine environment. These structures do not merely suffer from variable cyclic loading due to wind, waves and current, but also from corrosion. Their interaction can give rise to corrosion fatigue, thus reducing the service life and integrity of the structure. The research community witnesses a challenge to identify damage mechanisms of combined fatigue loading and corrosion, and to link this to the lifetime prediction of offshore structures. In this paper, a non-linear corrosion fatigue model is proposed to describe damage accumulation based on continuum damage mechanics. Fatigue endurance limit, load frequency and corrosion rate are included in the model as basic parameters which influence the interaction between fatigue and corrosion. A sequential load effect is revealed via integration of the non-linear accumulation of damage. Parametric studies are conducted to show the abilities of the model. Preliminary simulation results agree to a strong extent with experimental data in the form of corrosion fatigue S-N curves. Nonetheless, deviations are observed at lower life times and these are prone to further investigation. In the future, parameters will be calibrated and further validation experiments will be performed.
Hydrogen-assisted fatigue crack growth in ferritic steels – a fractographic study
Authors: Wan Di , Alvaro Antonio , Olden Vigdis , Barnoush Afrooz
Published: May 2018

Fatigue crack growth (FCG) behavior of a Fe-3wt.%Si ferritic alloy under different environmental conditions using in-situ electrochemical (cathodic) hydrogen (H) charging has been investigated. Three frequencies have been applied. Results clearly show that the FCG rate increased by a factor spanning from 20 to 1000 times, depending on the loading frequencies, when compared to the reference test in air. Lower frequency leads to higher FCG rate. A comprehensive fractographic analysis was carried out: the area fraction of different fracture surface features was measured and taken into statistical analysis. Based on these investigations, the possible mechanisms of H-enhanced FCG are discussed. Similar tests in high-pressure H gas from other studies were also compared and discussed. These results give a preliminary understanding of H effect in fatigue crack propagation procedure in ferritic alloys.
A frequency dependent embrittling effect of high pressure hydrogen in a 17-4 PH martensitic stainless steel
Authors: Sezgin Jean-Gabriel , Yamabe Junichiro
Published: May 2018

The effects of hydrogen on tensile and fatigue-life properties of 17-4PH H1150 steel have been investigated by using a smooth, round-bar specimen for tensile tests and circumferentially-notched specimen for fatigue-life tests. The specimens were precharged by an exposure to 35-100 MPa hydrogen gas at 270°C for 200 h. For the 100 MPa hydrogen exposure, the steel showed a significant degradation in ductility loss, translated by a relative reduction in area, RRA, of 0.31. The fatigue-life test of the present notch specimen (stress concentration factor of 6.6) reflects the fatigue crack growth (FCG) for long cracks. The fatigue limit of the non-charged and H-charged notched specimens, defined by the threshold of non-propagation for long cracks, was not affected by hydrogen. At a higher stress amplitude, the H-charged specimen showed a significant FCG acceleration ratio compared to the non-charged specimen. Although, an upper bound of the FCG acceleration seemed to exist, this ratio was approximately 100. The fracture surface of the H-charged specimen was covered with quasi-cleavage (QC) at a lower stress amplitude and with a mixture of QC and intergranular (IG) facets at higher stress amplitudes. It has been suggested that a cycle-dependent crack growth accompanied by QC occurs at a lower stress amplitude, whereas a mixture of cycle-dependent crack growth (accompanied by QC) and time-dependent crack growth (accompanied by IG) occurs otherwise. This mixture justifies the 100 times FCG acceleration ratio in spite of the existence of the upper bound.