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The aim of the study is to select a cellulosic waste material from paper industry solid wastes and process it for sorbent production. Four different solid wastes were collected from a local paper production facility and rejects were selected due to its sorption capacity and processability. Oil sorption experiments were conducted according to the ASTM F 726-12 method. Effect of sorbent dosage, contact and dripping time, recovery of the oil, reusability of the sorbent and sorption from the water surface were also determined. Maximum oil sorption capacity was determined as 9.67, 12.92 and 12.84 g/g for diesel oil, 0W30 and 10W30 motor oils respectively for the static test and 8.27, 10.45 and 11.69 g/g for the dynamic test. An efficient and low-cost sorbent was produced from paper industry rejects that can be used on land and on water. © 2017 Elsevier Ltd, This study was funded by Bulent Ecevit University Scientific Research Funding Program with the project number of 2014-77047330-02 .

Kraft paper in combination with dielectric oil is the most common as insulation system used in power transformers. The most used oil in power transformers is mineral oil. However, dielectric oils based on natural esters possess some advantages in comparison with mineral oil such as higher biodegradability, fire safety and availability. Therefore, they might be the most ideal substitute for mineral oil. The introduction of a new material requires the evaluation of its degradation rate because this determines transformers’ life span. In order to assess the performance of new insulating systems based on vegetable oils, simulations to obtain the hot-spot temperatures in power transformers using vegetable oils and controlled laboratory experiments of ageing were carried out. The reason is that hot spot temperature inside windings of the oil-immersed power transformers is one of the main manifestations of the thermal stress which leads to aging of insulation systems. The research leading to these results has received funding from multiple sources during years but we would specifically like to acknowledge the support received in the later stages from the Spanish Plan Estatal de I+D under the grant agreement DPI2013- 43897-P.

The article describes the influence of humidity on the surface photodielectric properties of papers prepared from poly(ethyleneimine)-TiO2 nanoparticles-anthocyanin modified cellulose fibres. The anthocyanins were extracted from purple cabbage, beet-root, plum peel, red wine and red currant juice. The samples were conditioned to various relative humidities (from 9 to 100%) and illuminated with white visible light, ? ? 405 nm. The poly(ethyleneimine)-TiO2-anthocyanin modified samples showed similar photodielectric behaviour that can be clearly distinguished from the samples modified solely with poly(ethyleneimine)-TiO2. Generally, an increase in humidity enhances the conductivity of the samples and induces an increase in the amount of photo-induced charge. Also, at higher humidities (above 80%), the samples with anthocyanin showed significantly higher values of photo-induced charges with respect to anthocyanin free samples. The presented results suggest that the presence of water molecules promotes electron-injection processes from the anthocyanin to the semiconductor surface. 2017 Elsevier Ltd This work was supported in part by the Ministry of Education and Science, Republic of Serbia (Project Nos. 171029 , 172056 , and 45020 ), by the Environment conscious energy efficient building TAMOP-4.2.2.A-11/1/KONV-2012-0068 project sponsored by the EU and European Social Foundation and by the National Research Foundation, South Africa (Grant No. 88301 ). Scopus

The poor wettability and high cost of the carbonaceous electrodes materials prohibited the practical applications of microbial fuel cells (MFCs) on large scale. Here, a novel nanoparticles of metal sheathed with metal oxide is electrodeposited on carbon paper (CP) to introduce as high-performance anodes of microbial fuel cell (MFC). This thin layer of metal/metal oxide significantly enhance the microbial adhesion, the wettability of the anode surface and decrease the electron transfer resistance. The investigation of the modified CP anodes in an air-cathode MFCs fed by various biocatalyst cultures shows a significant improving in the MFC performance. Where, the generated power and current density was 140% and 210% higher as compared to the pristine CP. Mixed culture of exoelectrogenic microorganism in wastewater exhibited good performance and generated higher power and current density compared to yeast as pure culture. The excellent capacitance with a distinctive nanostructure morphology of the modified-CP open an avenues for practical applications of MFCs. This work was supported by the National Research Foundation of Korea (NRF) via a grant funded by the government of Korea ( MSIP ) (Grant No. 2015R1C1A1A01054039 ) and in part by Open Laboratory Operational Business Developing and Diffusing the Regional Specialization Technology funded by the Busan Institute of S&T Evaluation and Planning (BISTEP) . Appendix A Scopus

Nanostructured materials are difficult to prepare rapidly and at large scale. Melt-processed polymer-clay nanocomposites are an exception, but the clay content is typically below 5 wt%. An approach ...

The present paper investigated an Integrated Fixed Film Activated Sludge (IFAS) Membrane BioReactor (MBR) system monitored for 340 days. In particular, the short-term effects of some operational parameters variation was evaluated. Results showed a decrease of the removal rates under low C/N values. Respirometry results highlighted that activated sludge was more active in the organic carbon removal. Conversely, biofilm has a key role during nitrification. The major fouling mechanism was represented by the cake deposition (irreversible).

Sustainable bioelectrogenesis was evaluated by oxidizing the organics of food waste leachate (FWL) under the influence of magnetic field (MF) and short term applied voltage (electric potential, EP). Adaptation of MF (20–220 m T) and EP (100−500 mV) had enhanced the performance of MFC in terms of power generation and reduction of organic in FWL. The best performance of MFC was noted with a MF at 220 m T and EP at 500 mV. MFC under the influence of applied EP (100−500 mV), the power generation was increased from 493 mW/m2 to 832 mW/m2. During this operation, the chemical oxygen demand removal (CODr) was also increased from 51.3 % to 80.4 %. Whereas the control MFC (MFC-C) had exhibited a maximum power generation and CODr of 224 mW/m2 and 36.3 %, respectively. MFC with MF has showed an increase in power density from 480 mW/m2 to 811 mW/m2. MFCs at 220 m T and 500 mV has exhibited, 262 % and 271 % increase in power density over control, respectively. Adaptation of MFC under the EP and MF were found to be beneficial in treating FWL which has high strength organic content.

Treatment and the recovery of textile wastewater are important due to their high volume and toxicity. Although several studies have been conducted on the use of membrane bioreactors (MBR) for textile wastewater treatment, they have mainly focused on synthetic wastewater or aerobic MBRs. However, anaerobic MBR (AnMBR) offers potential advantages of high color removal with lower energy consumption. In this context, this study aims at investigating the performance of AnMBR for the treatment of real textile wastewater. In addition to treatability studies, the membrane foulants were investigated in detail, which may be used in the design and operation of real scale plants. The permeate COD and color concentrations were decreased down to 70 mg/L and 150 Pt-Co, respectively. In the GPC analysis, pollutants with molecular weights greater than 15 kDa detected in the supernatant were removed by the dynamic cake layer developed on the membrane and only low molecular weight organics appeared in the permeate. AnMBR was operated successfully at a flux of 4.1 ± 0.7 LMH with a cleaning cycle of once a week. The impact of physical and chemical cleaning of the fouled membrane on the TMP elevation rate was also evaluated to determine the cleaning efficiency.

The organic fraction of municipal solid waste (OFMSW) is an abundant and sustainable substrate for the anaerobic digestion (AD) process, yet ammonia released during OFMSW hydrolysis could result in suboptimal biogas production. Acclimatized ammonia tolerant microorganisms offer an efficient way to alleviate ammonia inhibition during AD. This study aimed to achieve an efficient AD of OFMSW under extreme ammonia levels and elucidate the dynamics of the acclimatized microbial community. Thus, two mesophilic continuous stirred tank reactors (CSTR), fed only with OFMSW, were successfully acclimatized up to 8.5 g NH4+-N/L, and their methane yields fluctuated

Quick algae harvesting methodologies relating optimum flocculent dose (DOpt.), percentage harvesting efficiency (%HE) and percentage water recovery (%WRecovery) to the in-situ hydrodynamic properties of water-algae systems are presented. Flocculation of three microalgae in single and sequential steps, using chemical (polymer and ferric chloride) and biological (egg shells) flocculants, was studied. Zeta potential and pH analysis were completed to further understand the flocculation mechanism. Polymer at DOpt. of 7.0 g/kgDS resulted in WRecovery of 90% and %HE of 96.7%. Lower %HE (92.1), %WRecovery (79) and noticeable algal cells deformation was observed for ferric chloride at DOpt. of 7.0 g/kg DS. Bio-flocculant conserved algal structure and resulted in %HE of 96.2 and %WRecovery of 90 at DOpt. of 5.4 g/kgDS. Significant % HE of 99.8, %WRecovery of 99.8%, and up to 95% reduction in DOpt. were achieved in sequential flocculation. The results established the effectiveness and suitability of sequential/ bio-flocculation for algae harvesting. - 2019 Scopus

This work investigates the application of a hybrid system that combines forward osmosis (FO) and reverse osmosis (RO) processes for the supply of a fertilizing solution that could be used directly for irrigation purposes. In the FO process the feed solution is treated sewage effluent (TSE) and two different types of draw solutions were investigated. The impact of the feed solution and the draw solution flowrates and the membrane orientation on the membrane flux were investigated in the forward osmosis process. RO was used for the regeneration of the draw solution. In the forward osmosis process it was found that the highest membrane flux was 13.2 LMH. The FO process had high rejection rates for total phosphorus and ammonium which were 99% and 97%, respectively. RO achieved 99% total salts rejection rate. Seawater RO (SW30HR) and brackish water RO (BW30LE) membranes were used for the regeneration of the draw solution. The specific power consumption for the regeneration of the draw solution was 2.58 kW h/m3 and 2.18 kW h/m3 for SW30HR and BW30LE membranes, respectively. The final product water had high quality in terms of total dissolved solids concentration but the concentration of phosphorus was slightly higher than recommended due to adding 0.1 M of diammonium phosphate in the draw solution. - 2019 Elsevier Ltd This project is supported by Qatar National Research Fund (QNRF) under Qatar Research Leadership Program - Graduate Sponsorship Research award -GSRA4-2-0402-17013-. The authors also wish to thank Qatar Works Authority (Ashghal) for the supply of the treated wastewater. Scopus

The present study focused on 11-nor-9carboxy-Δ9-THC (THC-COOH) and Benzoylecgonine (BE), the most common metabolites of cannabis and cocaine, respectively, present in the domestic sewage entering the wastewater treatment plants. The aims of the study were: (1) to validate the analytical method of detection in wastewater and sludge; (2) to determine contribution of biodegradation and other processes to the removal in the biological reactor of the wastewater treatment plant (WWTP) and the response of biomass to different drug concentrations. The Ultra-Performance Liquid Chromatography coupled to tandem Mass Spectrometry method showed to be repeatable and reliable (recovery75%; repeatability10-15%; bias uncertainty10) for measurements in wastewater; the ultrasound assisted extraction (USE) demonstrated to be reliable as pre-treatment of activated sludge solid phase. Both drugs were fully removed from the liquid phase in the lab-scale biological reactor within 24 h. Biodegradation was the main BE removal mechanism, and the first order kinetic model provided the best fitting of the experimental data. THC-COOH was mainly removed due to a combination of adsorption and biodegradation; adsorption was better described by the pseudo-second order kinetic model and the Freundlich isotherm. Both drugs at the higher concentrations caused inhibition of nitrogen oxidation and carbon removal.

A halo-tolerant Tetraselmis sp. was grown in a 100,000 L raceway pond in the Qatari desert environment. As the biomass density reached 0.679 g/L, after 7 days, five different harvesting methods (i.e., cross-flow filtration, electrocoagulation, and coagulation-flocculation by FeCl3, NaOH, and alum) were applied to harvest the biomass. Hydrothermal liquefaction, for all the harvested biomass, was conducted at 350 °C for 30 mins in 10 mL Swagelok unions. The biocrude yield from cross-flow processed biomass (i.e., control) was 50.8%. Biocrude yield from electrocoagulation and alum processed biomass were 62.7% and 60.4% respectively where aluminum could have a catalytic effect. Biocrude yield from FeCl3 and NaOH processed biomass were 42.9% and 19.8% respectively. The total fraction of alkenes and alkanes was higher in the biocrude obtained from alum-harvested biomass, compared to other biocrude samples. However, the transition of metal species from biomass to biocrude was very low in all the biocrudes. The authors would like to acknowledge the support of Qatar National Research Fund (QNRF, a member of Qatar Foundation) for providing the funding (under grant NPRP8-646-2-272 ) for this study. The authors appreciate the assistance of Dr. Ahmad, Mr. Attia, and Mr. Solaiman of Central Laboratory unit (QU) for the sample analyses using CHNS, EDX, and FTIR. The authors also appreciate the assistance of Ms. Noora from Environment Science Center (QU) for biocrude analysis using GC-MS. Appendix A Scopus

A new protocol for polyhydroxyalkanoates (PHA) extraction from mixed microbial cultures (MMCs) is proposed. PHA-accumulating capacity of the MMC was selected in a sequencing batch reactor (SBR) fed with a synthetic effluent emulating a fermented oil mill wastewater (OMW). The highest recovery yield and purity (74 ± 8% and 100 ± 5%, respectively) was obtained when using NH4-Laurate for which operating conditions of the extraction process such as temperature, concentration and contact time were optimized. Best conditions for PHA extraction from MMC turned to be: i) a pre-treatment with NaClO at 85 °C with 1 h of contact time, followed by ii) a treatment with lauric acid in a ratio acid lauric to biomass of 2:1 and 3 h of contact time.

In this study, solid lignin produced from lignin liquor which is a waste of paper industry, and Sb 2 O 3 , MnSO 4 ·H 2 O, K 2 (SbO) 2 C 8 H 4 O 10 ·3H 2 O and FeSO 4 ·H 2 O were investigated in terms of their reducing effect on Cr(VI) and other effects on cement properties. Test results revealed that Sb 2 O 3 and MnSO 4 ·H 2 O are able to reduce Cr(VI) effectively when they were used at levels of 0,02% and 0,25% by weight of cement respectively and these amounts in cement did not cause any negative effect on concrete properties of cement. Also, they performed stable reducing effects when exposed to high temperature tests and shelf life tests and it is concluded that they can be used conveniently to reduce Cr(VI) in cement industry.

Whilst the fouling of MBR membrane surfaces has been very extensively explored by the academic community, there is an increasingly widespread recognition by practitioners of the issue of clogging of membrane channels with sludge solids, sometimes termed ?sludging?. The study undertaken has quantified this phenomenon using a bespoke test cell allowing a flat sheet membrane channel to be viewed directly during operation and the accumulated solids determined by digital image processing. Sludging behaviour has then been correlated both with the sludge properties, from sludge samples taken from both an industrial and municipal MBR, and the permeability decline rate data. The work has revealed the expected trends in fouling propensity, as quantified by the exponent n of the ?p/?t = m.exp(nJ) correlation from classical flux-step tests. With zero membrane aeration the industrial samples exhibited sludging, the filling of the complete thickness of the membrane channel with sludge solids, whereas for municipal sludge the solids formed a cake layer which did not fill the channel. In the absence of sludging the permeability decline followed the expected pattern of increasing at the elevated soluble COD and capillary suction time values of the industrial sludge, compared with municipal sludge at the same solids concentration range (8?12 g.L?1). However, there was no evident correlation between fouling (permeability decline without sludging) and sludging: incipient sludging did not appear to influence permeability, though can be assumed to negatively impact on long-term operation, or relate to the sCOD concentration. Sludging instead appeared to depend on the sludge physical properties, and primarily the viscosity: sludge samples at high viscosities were found to exhibit a different air-scour pattern to that at normal MLSS concentrations. Outcomes suggest that sludging is caused by rheological conditions promoting bubble coalescence and bubble stream constriction, reducing the exposure of the membrane surface to scouring air. This work was made possible by the support of a National Priorities Research Programme (NPRP) grant from the Qatar National Research Fund , grant reference number NPRP8-1115-2-473 . The statements made herein are solely the responsibility of the authors. The authors would like to thank Ashgal, Suez and Qatar Gas for their unstinting support of this work, as well as Kubota Membranes Europe for supplying the membranes and Yousef Elhamarnah for his assistance with the sampling. Scopus

Hybrid based bioelectrochemical system (BES) configured with embedded anode and cathode electrodes in soil was tested for the bioelectrochemical degradation of petroleum refinery wastewater (PRW). Four applied potentials were studied to optimize under batch mode operation, among which 2 V resulted in higher COD degradation (69.2%) and power density (725 mW/m2) during 7 days of operation. Further studies with continuous mode of operation at optimized potential (2 V) showed that hydraulic retention time (HRT) of 19 h achieved the highest COD removal (37%) and highest power density (561 mW/m2). BES function with respect to treatment efficiencies of other pollutants of PRW was also identified with respect to oil and grease (batch mode, 91%; continuous mode, 34%), total dissolved salts (batch mode, 53%; continuous mode, 24%) and sulfates (batch mode, 59%; continuous mode, 42%). Soil microenvironment in association with BES forms complex processes, providing suitable conditions for efficient treatment of PRW. ? 2018 Elsevier Ltd This publication was made possible by NPRP grant # 8-594-2-244 from the Qatar National Research Fund , Qatar (a member of Qatar Foundation). The findings achieved herein are solely the responsibility of the authors. Scopus

Stricter effluent limits, water shortage conditions, land availability requires today even more the needs of advanced wastewater treatments. Attractive solutions come from membrane bioreactors (MBR), Integrated Fixed Film Activated Sludge (IFAS) or combinations (i.e., IFAS-MBRs). One crucial aspect for the applicability of this overall new technology, compared to the conventional activated sludge systems, is the lack of knowledge for design and manage (e.g., kinetic constants, optimal operative conditions etc.). In view of the above frame, the aim of the present study was to assess the kinetic and stoichiometric parameters of bacterial species in MBRs by means of respirometric techniques. Plant configurations, operational conditions and wastewater features (domestic/industrial) were analysed. Four different MBR plants were investigated: i) sequencing batch MBR subjected to a gradual salinity increase; ii) pre-denitrification MBR treating saline wastewater contaminated by hydrocarbons; iii) University of Cape Town (UCT) MBR treating domestic wastewater subjected to a carbon-to-nitrogen (C/N) ratio variation; iiii) UCT- IFAS -MBR treating domestic wastewater. Results show a significant influence on biomass respiratory activity from both plant configurations and operational conditions. The salinity increase severely affected the activity of autotrophic species, while heterotrophic community was mainly influenced by the C/N variation. Moreover, it was observed a specialization in the IFAS-MBR configuration, with the suspended biomass more affine to organic matter, whilst biofilm in the nitrification process. The respirometric analysis confirmed to be an effective tool for the evaluation of the biomass kinetic and stoichiometric parameters. The results of this study can be useful for the application of mathematical models in the design phase and for the monitoring of biomass viability during plant operations.

Electrochemically active anodic biofilm that has adapted under mild applied potentials in the range 100-500 mV was evaluated for its improved bioelectrogenesis and bioelectrochemical treatment of petroleum refinery wastewater (PRW) in a single chamber air cathode microbial fuel cell (MFC). MFC operation with 500 mV as supplemental voltage has exhibited a maximum power density of 132 mW/m2, which was three times higher than control MFC (45 mW/m2). Similarly, highest substrate removal efficiency (48%) was also obtained with the MFC of 500 mV, followed by 300 mV (37%), 100 mV (32%) and control (27%). Adaptation under applied potential conditions also exhibited enhanced degradation efficiency of diesel range organics (DROs)/straight chain-alkanes. The strategy efficiently reduced DROs with the maximum efficiency of 89% (500 mV), which is almost 50% higher than that of the control system (59%), demonstrating the effectiveness of using supplemented voltage in treating PRW. 2018 Elsevier Ltd This publication was made possible by NPRP grant # 6-289-2-125 from the Qatar national research fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The Authors would like to acknowledge the Environmental Science Centre (ESC), Qatar University for evaluating the samples for diesel range organics (DROs). Scopus

Photocatalysis and photocatalytic ozonation under visible light have been applied for the purification of a complex aqueous matrix such as the grey water of Masdar City (UAE), by using N-doped brookite-rutile catalysts. Preliminary runs on 4-nitrophenol (4-NP) solutions allowed to test the reaction system in the presence of a model pollutant and to afford the relevant kinetic parameters of the process. Subsequently, the remediation of grey water effluent has been evaluated in terms of the reduction of total organic carbon (TOC) and bacterial counts. The concentration of the most abundant inorganic ionic species in the effluent has been also monitored during reaction. Photocatalytic ozonation under visible light allowed to reduce the TOC content of the grey water by ca. 60% in the optimized experimental conditions and to reduce the total bacterial count by ca. 97%. The extent of TOC mineralization reached ca. 80% when the photocatalytic ozonation occurred downstream to a preliminary electro-membrane bioreactor (eMBR). Coupling the two processes enhanced the global efficiency. In fact, the eMBR treatment lowered the turbidity and the organic load of the effluent entering the photocatalytic ozonation treatment, which in turn enhanced the extent of purification and disinfection.

The cultivation of microalgae as a feedstock for renewable fuels is widely touted as a way to sequester CO2while negating food versus fuel competition for land. However, the widespread industrial use of microalgae for biofuels has yet to reach a critical stage based on lipid extraction alone. One alternative to the transesterification of microalgae for liquid fuel production is to use thermochemical conversion techniques. In the present work, we demonstrate that Dunaliella tertiolecta can be converted to biofuels via pyrolysis at temperatures significantly lower than terrestrial biomasses. The primary gaseous pyrolysis products were CO2, H2O, CH4, alcohols, aldehydes, organic acids and phenols. The iso-conversional distributed activation energy model was used to calculate the kinetic parameters, showing average activation energy of 243.3 kJ/mol, with a peak in activation energy at mass fraction conversions between 0.45 and 0.65. However, the substantial amount of pyrolysis gases evolved at low temperatures (between 280 and 320 °C), suggests that pyrolysis at higher temperatures, and especially to completion, might not be necessary to optimize pyrolytic production of biofuels from microalgae. © 2016 Elsevier Ltd Ondokuz Mayis Ãœniversitesi: 214M153 The authors thank Gulcin Tugcu for cultivating D. tertiolecta. This study was supported by Ondokuz Mayis University with a project number of PYO.MUH.1904.15.012 and TUB?TAK with a project number of 214M153.

Hydrogen has attracted huge interest globally as a durable, environmentally safe and renewable fuel. Electrocatalytic hydrogen evolution reaction (HER) is one of the most promising methods for large scale hydrogen production, but the high cost of Pt-based materials which exhibit the highest activity for HER forced researchers to find alternative electro-catalyst. In this study, we report noble metal free a 3D hybrid composite of tungsten-molybdenum oxide and reduced graphene oxide (GO) prepared by a simple one step hydrothermal method for HER. Benefitting from the synergistic effect between tungsten-molybdenum oxide nanowires and reduced graphene oxide, the obtained W-Mo-O/rGO nanocomposite showed excellent electro-catalytic activity for HER with onset potential 50 mV, a Tafel slope of 46 mV decade −1 and a large cathodic current, while the tungsten-molybdenum oxide nanowires itself is not as efficient HER catalyst. Additionally, W-Mo-O/rGO composite also demonstrated good durability up to 2000 cycles in acidic medium. The enhanced and durable hydrogen evolution reaction activity stemmed from the synergistic effect broadens noble metal free catalysts for HER and provides an insight into the design and synthesis of low-cost and environment friendly catalysts in electrochemical hydrogen production.

The presence of microorganisms is one of the main causes of monument deterioration. Biocides are usually applied after or before restoration in order to prevent or slow down microbial growth. Frequent applications are necessary leading to increased costs and high risks to humans and the environment. The aim of this study is the design of novel controlled release systems comprising a biocide loaded into a mesoporous silica. Pristine MCM41 as well as MCM41 functionalised with carboxy- (MCM41-COOH) and amino-groups (MCM41-NH2) were used. Biotin T and New Des 50, two commercial formulations, were chosen as biocides. The biocide encapsulation was performed adding the mesoporous silica to an aqueous biocide solution. The release of the biocides in water was investigated by UV-Visible Spectroscopy. A further characterisation of the systems was performed to evaluate their structure and features and to speculate about the mechanisms involved in the release. The effect of both surface modifications on the release of biocides, as well as the biological activity of the systems were tested. The high-performing system was applied on a stone specimen from a fountain in Diamantina (Minas-Gerais, Brazil) to assess the effect on the microbial community up to 12 months.

In this work, the manufacturing and characterization of an optically transparent and UV-Iight photoactive anode, formed of monolayer graphene grown by chemical vapor deposition (CVD) and decorated with a close packed multHayered nanostructured layout of colloidal TiOz nanocrystals (NCs), are reported. The hybrid material has been prepared by a facHe solution-based procedure, which relays on soaking the CVD graphene in a solution of I-pyrene butyric acid (PBA) surface coated Ti02 NCs, achieved upon implementation of a capping exchange process for displacing the pristine organic ligand deriving from the colloidal synthesis. Pyrene undergoes 'It- 'It stacking interactions, anchoring the NCs to the platform with retention of the NC geometry and composition. The NCs immobilize onto the graphene platform with preservation of its aromatic structure and the resulting hybrid has been found optically transparent in the visible spectral range. (Photo)electrochemical investigation shows that the composite material has a promising sensitivity for selectively detecting dopamine and norepinephrine and, concomitantly, exhibits a (photo)electric activity higher than that of bare graphene. Thus, the achieved hybrid material results interesting for the manufacturing of photo-active components to integrate in photorenewable sensor elements along with photodetectors and solar cells

Bio-hydrogen, obtained by fermentation of organic residues, is considered a promising source of renewable energy. However, the industrial scale H 2 production from organic waste is far to be realized as technical and economical limitations have still to be solved. Low H 2 yields and lack of industrially robust microbes are the major limiting factors. To look for bacteria with both interesting hydrogen fermentative traits and proper robustness, granular sludge from a brewery full scale Upflow Anaerobic Sludge Blanket (UASB) digester was selected as trove of microbes processing complex substrates. One hundred and twenty bacterial strains, previously isolated from heat-treated granular sludge and genetically identified by 16S rDNA sequencing, were screened for extracellular hydrolytic enzymes on cellulose, hemicellulose, starch, pectin, lipids, protein. The most interesting hydrolytic strains were assessed for their H 2 production from glucose and soluble starch. Two Bacillus sp. strains, namely F2.5 and F2.8, exhibited high H 2 yields and were used as pure culture to convert Organic Fraction of Municipal Solid Waste (OFMSW) into hydrogen. The strains produced up to 61 mL of H 2 per grams of volatile solids and could be considered as good candidates towards the development of industrially relevant H 2 -producing inoculants. This is the first successful application of pure microbial cultures in bio-hydrogen production from OFMSW.

Olive pomace (OP) and olive mill wastewaters (OMW) are two residues that are derived from olive oil production. The high TS content and the presence of polymeric ligno-cellulosic compounds impart a very high viscosity value of about 180 cP to the OP–OMW mixture. In this condition, the Rushton impeller, which is normally used in digesters, is unable to guarantee a homogenous mixing of the reactor medium. Four different impellers have been tested with the aim of improving the mixing of the reaction medium: a Pelton Impeller, a Rushton impeller with six 45° inclined blades, a marine impeller (MI) with three blades and an anchor impeller (AI). The marine and the anchor impellers have permitted homogenization of the reaction medium and have consequently led to a good biogas production. Therefore, these two impellers have been used in combination with a two-stage AD configuration, based on the separation of the two distinctly different groups of bacteria (acidogens and methanogens), in order to reproduce the optimal operative conditions for the different microorganisms in each stage. The tests have demonstrated that an AI can be recommended for a one-stage configuration, while a MI is necessary for a two-stage configuration.

Due to their structural performance and durability, Fibre Reinforced Concrete (FRC) precast segments are now commonly used in major tunnelling applications around the world. The paper investigates the effects of irregular loading on the segments due to poor alignment, which can occur on the tunnel lining during construction as a result of the operation of the Tunnel Boring Machine (TBM). During construction, as the TBM progresses, defects on the tunnel lining can arise. Cracks can then be caused by improper load application by the TBM thrust jacks (due to uncorrected inclination or eccentricities). Further defects can be caused by non-uniform ring joints and this needs to be taken into account in the design and construction of the lining. Because the precast segments are not supported uniformly by the previous ring, they are subjected to a transient bending moment that can jeopardise their integrity and performance during both the excavation phase and service life. The proposed hybrid solution of FRC segments with Glass Fibre Reinforced Polymer (GFRP) reinforcement presented in this paper can overcome these situations, which cannot be satisfied with FRC-only segments, by means of an “elastic-return action” provided by the GFRP reinforcement. Two full-scale tests simulating the TBM thrust, for which irregular support conditions were taken into account, were carried out. Based on the obtained results, it is concluded that the proposed hybrid solution shows almost full recovery of the initial geometry with residual crack widths measuring 79% less compared to the FRC-only solution.

This paper presents the results of STRATONAV experiment to test the precision of the VOR (VHF Omni Range) aircraft navigation system in stratosphere. The experiment has been conducted by the S5Lab research group at Sapienza University of Rome in the framework of the REXUS/BEXUS Programme. STRATONAV has been successfully launched on-board the BEXUS 22 stratospheric balloon from Esrange Space Center in Kiruna, Sweden, in 2016. The main payload was composed by two typologies of VOR receivers, a commercial portable receiver and a Software Defined Radio (SDR), alongside the bus and positioning, attitude and temperature sensors. STRATONAV succeeded in collecting VOR radials for the whole duration of the balloon flight. The results prove that VOR can be used as back-up navigation system for stratospheric platforms, ensuring a reliability improvement, while being applied to smaller payloads as primary system for a cost and complexity reduction of experiment developments. The paper analyzes the collected VOR data during the balloon flight. Accuracy and performance plots with respect to distance from the VOR stations and altitude are presented and discussed. The mean errors and standard deviations from all stations for both the receivers are shown with an analysis over the recorded errors. Finally, future perspectives, analyses and applicability of the research are exposed.

With the increasing number of satellite launches, especially in Low Earth Orbit (LEO), optical tracking can offer a convenient enhancement of tracking precision and availability. Spaceborne active illumination devices, such as LED payloads, can offer a significant improvement to optical observations, extending the observability interval to the whole eclipse time and performing optimized flash sequences for identification, orbit determination, attitude reconstruction or low data rate communication. The main features of LED panels for optical tracking mounted on small satellites platforms (and with particular regards to nano-satellite platforms) are outlined in this paper, along with the description of the design drivers. The analysis of the performance is referred to Sun-Synchronous (at 700 km of altitude) and International Space Station (400 km) orbits, while the ground segment and the optical link budget reference design relies on a standard university space debris observation station architecture. The paper also outlines the advantages of using different observation techniques and the variety of flashing patterns. The LEDSAT 1U CubeSat, aiming at demonstrating the effectiveness of an LED-based payload for observation and tracking, is used as a study case for examples of the LED payloads and related operations that are reported and described in this paper.

Nadir remote sensing of the night side of Mars is challenging, mainly due to the low signal-to-noise ratio of such observations. We show in a companion paper that the abundance of carbon monoxide (CO) during night can be retrieved from the observations of the Planetary Fourier Spectrometer (PFS). This requires, however, an accurate knowledge of the temperature profile, and especially of the night-time thermal inversions, to properly model the atmospheric emission. While the temperature profile is usually retrieved from the ν2 band of CO2 (centered at 667 ​cm−1), this work shows that, for averaged night-time PFS observations built from a large ensemble of spectra, the temperature profile can be retrieved from the more saturated ν3 band of CO2 (centered at 2349 ​cm−1). We show especially that, due to IFOV (instantaneous field-of-view) size differences and boresight offset between the longwave and shortwave channels of PFS, the temperature profile retrieved from the ν3 band is more consistent with the emission observed in the 1-0 band of CO (centered at 2143 ​cm−1), which is used in the second part paper. We provide a complete characterization of the retrieved temperature profiles in terms of error and vertical sensitivity. Using this, we show that using the ν3 CO2 band allows to properly constrain and characterize the thermal inversions encountered near the surface for most night-time observations. The resulting set of temperature profiles is essential for the retrieval of the night-time CO abundance that is presented in the companion paper. Beyond their usefulness for the night-time CO retrieval, we suggest with a last example that temperature profiles retrieved from the ν3 band of CO2 could be use more generally to study surface thermal inversions encountered at night.

In this paper, a general strategy is presented for optimizing water resources in industrial activities taking into account fluctuations of water flow-streams and water contents in feed and products as well as in the utility system. Indeed, considering fluctuations can be of primary importance for several water intensive industries such as the food or the paper&pulp industry. Furthermore, whenever the water balance includes the water content of products (as is typically the case for the food industry) fluctuations in the composition of products can considerably affect the overall balance due to water being a major component of many foods. Therefore, the currently used optimization strategies that disregard water fluctuations, can lead to a severe bias in the water balance and thus overlook the potential of water recovery and reuse. Including this aspect in widely used algorithms for process monitoring (data reconciliation) and optimization might lead to a possibly prohibitive increase in the computational burden. In particular, it is shown in this paper that the resulting optimization algorithm should solve a dynamic non-convex stochastic Mixed Integer Nonlinear Programming problem. To tackle this (typically NP-hard) problem, a strategy has been developed that combines ordinal optimization for dealing with statistical information and nonlinear, non-convex deterministic algorithms. The outlined strategy has been applied to a complex process in the food industry (production of starch and starch-based products). The results seem to confirm the general validity of the algorithm developed.

In this paper, a new shock-fitting technique based on unstructured dynamic grids is proposed to improve the performances of the unstructured “boundary” shock-fitting technique developed by Liu and co-workers in [1, 2]. The main feature of this new technique, which we call the “embedded” shock-fitting technique, is its capability to insert or remove shocks or parts thereof during the calculation. This capability is enabled by defining subsets of grid-points (mutually connected by lines) which behave as either “common”- or “shock”-points, shock-waves being made of an ordered collection of shock-points. Two different sets of flow variables, corresponding to the upstream and downstream sides of the shocks, are assigned to the shock-points, which may be switched to common- and back to shock-points, a feature that allows to vary the length of the existing shocks and/or make new shock-branches appear. This paper illustrates the algorithmic features of this new technique and presents the results obtained when simulating both steady and un-steady, two-dimensional flows.

Building renovation is urgently required to decrease the energy consumption of the existing building stock and reduce greenhouse gas emissions coming from the building sector. Selecting an appropriate renovation strategy is challenging due to the long building service life and consequent uncertainties. In this paper, we propose a new framework for the robust assessment of renovation strategies in terms of environmental and economic performance of the building's life cycle. First, we identify the possible renovation strategies and define the probability distributions for 74 uncertain parameters. Second, we create an integrated workflow for Life Cycle Assessment (LCA) and Life Cycle Cost analysis (LCC) and make use of Sobol’ indices to identify a prioritization strategy for the renovation. Finally, the selected renovation scenario is assessed by metamodeling techniques to calculate its robustness. The results of three case studies of residential buildings from different construction periods show that the priority in renovation should be given to the heating system replacement, which is followed by the exterior wall insulation and windows. This result is not in agreement with common renovation practices and this discrepancy is discussed at the end of the paper. ISSN:0360-1323 ISSN:0360-1323

The paper presents climatology of the mean winds and diurnal and semidiurnal tides observed by meteor radars at high latitudinal stations Svalbard (78°N, 16°E) and Tromso (70°N, 19°E) based on 18 years (2001–2018) and 16 years (2003–2018) of measurements, respectively. The main focus of the study is to clarify the features of the diurnal tide (DT) because it is poorly known particularly at high latitudes. The detailed analysis of both tidal amplitudes and phases indicated that the seasonal and altitude structure of the DT at these two not very distant stations are significantly different. Moreover, a very unusual vertical structure of the DT at Tromso has been found where above altitudes of ~88–90 km the zonal and meridional components have opposite directions of vertical propagation. This unusual vertical tidal feature has been supported by the climatology of the DT obtained by the MF radar situated at Tromso for the period of time 1997–2019. The paper presents also the comparison of the radar observations with two models: the assimilated CMAM-DAS and the specified dynamics (SD) WACCM-X. The WACCM-X simulated DT supports to large extent the climatology of the DT at Tromso while the assimilated CMAM-DAS reproduced the evanescent character of the tide in summer up to altitude of ~88 km with almost the same amplitudes and phases as the observed ones. These results could be used as benchmarks for model simulations for understanding the forcing mechanisms of the DT at high latitudes of the considered region.

Earth observation is one of the most important satellites’ applications. Past earth observation systems have used traditional space technology to achieve the best possible performance, but have been very expensive. Recently, thanks to advancements in technology and modern microelectronics, small satellites have become more and more useful at much lower costs, even if with reduced performance. The resolution of the optical payload improves as the altitude is reduced. Space system mass is proportional to the cube of the linear dimensions. This means that by flying at lower altitudes, satellites can reduce their payload size and therefore the entire mass of the satellite, thus reducing the cost of the system dramatically. However, almost all the earth observation missions fly at the minimum altitude that provides a sufficient orbital life. The addition of a propulsion system capable of providing drag compensation for the entire satellite operative life provides the possibility to fly at very low earth orbit. In this way, the same performance can be obtained with a smaller and cheaper system. To obtain the same coverage more units are needed to replace a larger unit at higher altitude. In this paper it is confirmed that future smallsat observation systems, operating at a lower altitude than traditional systems, have the potential for comparable or better performance, much lower overall mission cost (by a significant factor), lower risk (both implementation and operations), shorter schedules, lower up-front development cost, more sustainable business model, to be more flexible and resilient, more responsive to both new technologies and changing needs, and to mitigate the problem of orbital debris. This paper focus in particular on the effect of the propulsion system parameters (performance and costs) on the cost model as a function of the altitude. It is demonstrated that new affordable chemical propulsion systems provide already significant benefits with limited constraints, allowing a useful reduction of altitude and, consequently, costs. Electric propulsion systems have the potential to allow even lower altitudes or longer lifetimes; however, they have a stronger impact on the satellite design related to their power consumption, generally requiring deployable solar panels, which can limit the flexibility in the orbit selection or the added weight and cost of batteries. The development of electric thrusters that have good performance and limited impact on the satellite architecture (particularly at small scales) is fundamental to exploit their potential for reduced mission costs through very low altitude flight.

The closing sound of a car door is objectively not related to the intrinsic quality of the vehicle but it is an important subjective parameter for vehicle evaluation. For automotive developers, it is very interesting to deepen this phenomenon and to define a methodology to understand the influence of several parameters on door-closing sound quality. The aim of this paper is to evaluate the possibility of analysing this phenomenon, called car-door slamming, using a numerical simulation approach. Simulation methods for vibro-acoustic analysis are sufficiently robust and predictive in the case of simple systems, as it emerges from a parallel investigation conducted on an elementary component like an annular disk. In simulating complex systems, as in the case of door slamming, where non-linearities may be significant, methods are not always reliable and sufficiently predictive. In the specific case, the main difficulty is to correctly identify the dynamic behaviour of a trimmed car door, which is a very complex system. The paper reports an analysis and a comparison between the experimental and simulation results of the car-door slamming phenomenon, highlighting the dependence of the quality of the numerical results on the particular simulation method adopted. The paper also reports an experimental and numerical vibro-acoustic analysis of a trimmed car door isolated from the vehicle with no constraints (free-free condition) to ascertain its dynamic behaviour in a simpler condition not coupled to the vehicle. The result shows a significant level of system complexity even in this case.

Understanding rock deformation processes in solid Earth materials, from the crystal to the tectonic plate scale, is essential for characterising the evolution of the lithosphere and for predicting how rocks behave in the subsurface. Temperature is a key parameter that determines what rock deformation processes are active and therefore how tectonic structures form. Moreover, it controls the migration of fluids and melt in the Earth's crust that lead to phase transformations and changes in rock rheology. This special issue gathers a collection of research papers following the 21st International Conference on Deformation Mechanisms, Rheology and Tectonics (DRT-2017), which was held in Inverness (Scotland) in April–May 2017, organised by the University of Aberdeen. These contributions provide a significant advance in the study of rock deformation and fluid/melt migration at multiple crustal levels, from deformation bands near the Earth's surface to shear zones in partially molten rocks in the lower crust. In this introductory article, we first provide an overview of how temperature controls deformation mechanisms and processes and then introduce the collection of research papers ordered from those analysing deformation processes occurring at high temperatures to contributions reporting deformation at shallow crustal conditions.

In southern European countries, despite having mild winters, many people live in cold and energy-inefficient properties and struggle to meet their energy needs for comfort and warmth, and therefore they run the risk of developing cold-related illnesses. Although the relationship between health, energy poverty, and cold/warm homes has been analysed by numerous studies, the identification of the direct impact of this relationship on society remains elusive in these countries. This paper shows a case study in a working-class district of Seville, Spain. Six multi-family residential buildings (providing social housing for a total of seventy-one households), built prior to energy-efficiency regulations being in place, are retrofitted by Seville City Council. The Index of Vulnerable Homes, defined by the authors, assesses the vulnerability to energy poverty (pre- and post-intervention) of those households. Furthermore, the costs to the National Health Service (NHS) are also estimated. The results show that savings for the NHS could be used in order to define the payback period of those retrofitting funds. In conclusion, this paper presents how the Index of Vulnerable Homes would be able to help in the development of a comprehensive and coordinated strategy in social housing to address energy poverty, and in the monitoring of the effectiveness of ongoing projects in the city of Seville.

The main purpose of the study is to present a new approach to comparing EU regions according to their level of innovation. For many years, different organizations have published reports related to the innovation level of EU countries and regions. Usually, taxonomic methods are used to measure development in this area. The main disadvantage of this approach is that it offers an assessment of EU innovation level based only on the mean, while the main goal of this kind of analysis should include an assessment of results compatibility obtained in different areas constituting a composite measure. For this purpose, a different procedure based on the multi-criteria taxonomic method is proposed. In this method, the innovation level of every object (in the paper, EU regions) is assessed using results obtained in every group of indicators taken into account for this purpose. This means that EU regions can be divided into groups according their level of innovation in all considered areas, not only according to their mean value of development. This is the basic advantage of this type of analysis. An added value of the considerations presented in the paper is the possibility of obtaining supplementary information about the internal structure of the innovation of socio-economic objects. It should be emphasized that such analysis is a new approach to this kind of assessment. The results are especially relevant to associations such as the European Union, in which internal cohesion is one of its strategic developmental goals.

The Earth Space Elevator is an ingenious concept aimed at providing easy access to space, eliminating the need for rockets and potentially reducing drastically the launch costs. Technical advancements that could make the Space Elevator possible, among others, would be the availability of long carbon nanotubes or other super-strong and light material. This paper aims at addressing issues related with the stability of the system when the elevator is partially deployed starting from a nucleus in geostationary orbit (GEO). As noted by various authors, the energy increase needed to keep the orbital centre (where the gravity and centrifugal forces balance out) at GEO altitude during deployment while the tether is lengthened leads to an orbit with a positive orbital energy, i.e., the circular orbit has an energy level pertaining to a hyperbolic orbit. This situation leads to the instability of the unanchored system that would tend to escape from the geostationary orbit. The paper illustrates the change in orbital energy during assembly for a system made of a cylindrical tether and then investigate the stability of the coupled orbital and attitude motion in the orbital plane before anchoring. The analysis leads to the conclusion that the orbital motion instability ensues well before the orbital energy of the unperturbed system becomes positive.

3rd International Hydrogen Technologies Congress (IHTEC) -- MAR 15-18, 2018 -- Alanya Alaaddin Keykubat Univ, TURKEY, WOS: 000477092000031, With the acceleration of the development process of hydrogen fuel cell electric vehicles (HFCEV), it has become very important to maximize the energy stored in the vehicle and to use the vehicle with high efficiency. This paper puts forward how to cooperate with a proton exchange membrane fuel cell (PEMFC) as the primary energy source, a lithium-ion battery (LiB) and a supercapacitor (SCAP) as the energy storage technology. Furthermore, this paper examines the effect of two new control strategies developed for HFCEV in different road models on the vehicle fuel economy and life cycle of the system components. Both control strategies applied to the system can be easily applied to the different HFCEVs with minor changes due to the simplicity of their structure and parameters. The simulation results of the study have indicated that the impact of control strategies created in different road conditions on the power of energy sources, the life cycle of system components, system efficiency and fuel economy parameters of HFCEV. (C) 2018 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

This paper deals with the interpretation of the damage originated by the 2016 Norcia earthquake, Italy, in a deep tunnel excavated in a calcareous rock mass. A careful investigation of the damage pattern, together with the availability of seismic signals recorded in the vicinity of the tunnel during the earthquake, prompted a back-analysis of the observed phenomenon. The study hinged on a combination of site response analyses, simulation of the tunnel construction, and computation of the effect of the earthquake on the tunnel lining. Specifically, the damage caused by the earthquake in the tunnel lining was evaluated both with a decoupled procedure, based on equivalent static loading, and with a fully coupled dynamic analysis of the soil-structure interaction. The results obtained from the back-analysis were in a good agreement with the observations, and contributed to evidence the main causes of the damage, related to the specific geometry and to the dynamic response of the lining. The approach used in the paper, validated for the present case study through the comparison with the observed tunnel damage, may be useful to assess the seismic vulnerability of existing tunnels and for the seismic design of new underground structures.

Dry deposition process is one of the important pathways for the removal of particles from atmosphere. It is the result of a combination of different environmental and physical factors as atmospheric conditions, particle properties, characteristics of the canopy. For this latter factor, urban canopy represents unevenly combinations of different types of surface elements that increases the complexity of deposition process phenomena. Therefore, particle dry deposition on urban surfaces is not easy to configure and, although empirical or semi-empirical models in literature have been developed to address this aspect, there is not standardized and commonly accepted criteria, especially for submicron particles. In this paper, comparisons of different dry deposition models and measurement data by experimental campaigns, covering for different surface roughness conditions, i.e. from four Italian cities and urban environments of other countries, are performed. Giardina et al. (2017b) model, by using a Brownian diffusion resistance as proposed in this paper, seems to capture the main dry deposition processes for the examined contexts.

This paper presents an experimental study carried out on the structural performance of shear-critical reinforced concrete (RC) deep beams internally reinforced with two different stirrups configurations; i.e. aligned and unaligned with the fabric-reinforced cementitious matrix (FRCM) strips. The test matrix involved two unstrengthened (reference) beams and twelve strengthened deep beams tested under three-point bending. Three test variables were investigated: (a) the configuration of the internal transverse reinforcement (ITR), (b) the type of FRCM fabric (carbon, glass, and polyparaphenylene benzobisoxazole, PBO), and (c) the strengthening technique (externally bonded, EB, and near-surface embedded, NSE). Experimental results demonstrated an effective application of the FRCM in improving the load capacities (P max ) of deep beams; however, its performance depends on the test variables. The NSE-FRCM provided an inherent anchorage that prevented the premature debonding of the FRCM composite, which was a standard failure mode in the externally bonded FRCM strengthened beams. Finally, a simple strut and tie model (STM) is used to predict the load capacities of the deep beams strengthened with different FRCM systems and resulted in a satisfactory prediction with an average P th /P ex ratio of 1.11 and a standard deviation of 5.7%. - 2019 Elsevier Ltd This paper was made possible by NPRP grant # NPRP 7-1720-2-641 from the Qatar National Research Fund (a member of Qatar Foundation) and by Qatar University grants number QUST-CENG-SPR-13/14 and QUST-CENG-SPR-14/15-15 . The findings achieved herein are solely the responsibility of the authors. Appendix A Scopus

Large deployable antennas are required for the advancement of space communications, Earth observation, radio astronomy and deep space exploration. Most contemporary space antennas have exceeded the size of launching vehicles, leading to the necessity of stowed concepts to overcome the limitation. Many structural models have been investigated by different organizations. Generally, mesh deployable reflectors are currently more mature compared to other foldable solutions. This will be the topic of this paper. Orbital disturbances, perturbations originated by on-board sources and thermal deformations affecting the deployed configuration can deteriorate the accuracy of the communications system. Undesired dynamic behaviour of structural components has to be predicted and counteracted. Therefore, vibration control is a key technology to correct the distortions altering the proper functioning of the system. An intelligent active structure is introduced as a structure configured with distributed actuators and sensors and guided by a controller to modify the dynamic response of the system. In this paper, the supporting structure of a very large mesh reflector is described. A FEM formulation is adopted to assemble the frame and it is validated by comparing it with commercial codes. According to the adopted model, the active elements can be embedded in the middle of the truss elements. Of course, active control of all the devices at the same time requires a control effort which could be not affordable in space applications. However, the effectiveness is not the same for all the actuators. In this study, two cascade optimization procedures are performed to assess the best positioning and velocity feedback gains of the actuators that must be controlled to damp vibrations. In particular, a gradient-based technique is used after both a Genetic Algorithm and a Reinforcement Learning methodology to find the best set of gains for the controller. The objective function is set as a weighted sum of power consumption of the actuators. As a study case, the spacecraft implements a velocity feedback strategy when performing a generic attitude manoeuvre to coordinate the simultaneous action of the devices to ensure the damping performance of the system is enhanced. In addition, the impact of damaged actuators and uncertainties on the mechanical properties of the passive structure has been discussed and analysed.

Fabric-reinforced cementitious matrix (FRCM) composites are usually surface-applied for strengthening reinforced concrete (RC) structures. The efficacy of the FRCM strengthening systems is dependent on the FRCM/concrete bond performance. This paper reports on the experimental results of FRCM/concrete bond characterization through pull-off tests. Six FRCM-strengthened RC slabs ( mm) were prepared and enabled conducting 72 FRCM/concrete pull-off tests. The parameters investigated included: (a) FRCM material (carbon or polyparaphenylene benzobisoxazole (PBO)); (b) level of substrate roughness (no/low/high roughening); and (c) specimen's test age (7, 28, 56, and 84 days). All FRCM systems were single-plied. The study revealed a significance of the surface preparation and test age of specimens on the FRCM/concrete pull-off strength. High-roughness specimens showed an average of 74% pull-off strength increase compared to those without roughening. Also, specimens tested at Day 84 showed 54% strength increase compared to those tested at Day 7, on average. PBO-FRCM system showed slightly higher pull-off strength than that of the carbon counterpart. The specimens showed two distinctive failure types at the (i) fabric/mortar interface and (ii) concrete/matrix interface: the latter was more prominent in carbon-FRCM. Nonetheless, the failure mode was most dependent on the fabric geometry and the substrate roughness. Based on a statistical analysis of the tested specimens, prediction models were proposed for the FRCM/concrete pull-off strength and failure mode. This paper was made possible by NPRP grant # NPRP 7-1720-2-641 from the Qatar National Research Fund (a member of Qatar Foundation) and by grant # QUST-CENG-SPR-13/14 from Qatar University . The findings achieved herein are solely the responsibility of the authors. Scopus

Binary or multiple stellar systems, constituting almost a third of the content of the Milky Way, represent a high priority astronomical target due to their repercussions on the stellar dynamical and evolutionary parameters. Moreover the spectral study of such class of stars allows to better constrain the evolutionary theories of the Galactic stellar populations. By resolving the members of stellar systems through photometric observations we are able to perform more detailed measurements to infer their mass. In this paper we investigate the feasibility of a cubesat based mission including an optical payload to directly optically discriminate the members of a selected sample of binary systems. The scientific targets, consisting 11 M class dwarf stars binary systems, have been extracted from the already studied Riaz catalogue. These subset has been selected considering the star distance, the members angular separation, and the distance from the Galactic plane (due to limit the background and foreground contamination). The satellite concept is based on a 6 unit Cubesat embedding some commercial off the shelf components and an ad hoc designed optical payload occupying almost 4 units. The optical configuration has been chosen in order to fit the angular resolution requirements, as derived from the target characteristics. Moreover, according to the optical analysis and the computed field of view some requirements on the attitude control system have been inferred and fulfilled by the component selection. The paper is organized as in the following: a brief scientific introduction is made; consequently the project is described with particular attention to the optical design and the standard sub-systems; finally the conclusions are drawn and the future perspectives are investigated.

This paper is a comment on a previous published paper.

GaN-on-GaN vertical devices are expected to find wide application in power electronics, thanks to the high current densities, the low on-resistance and the high breakdown voltage. So far, only few papers on the reliability of GaN-on-GaN vertical devices have been published in the literature. This paper investigates the degradation of GaN-on-GaN pn diodes submitted to stress at high current density. The study was carried out by means of electrical characterization and electroluminescence (EL) measurements. We demonstrate that: (i) when submitted to stress at high current density, the devices show significant changes in the electrical characteristics: an increase in on-resistance/turn-on voltage, an increase in the generation/recombination components, the creation of shunt-paths. (ii) the increase in on-resistance is strongly correlated to the decrease in the EL signal emitted by the diodes. (iii) the degradation kinetics have a square-root dependence on time, indicative of a diffusion process. The results are interpreted by considering that stress induces a diffusion of hydrogen from the highly-p-type doped surface towards the pn junction. This results in a decrease in hole concentration, due to the creation of Mg H bonds, and in a lower hole injection. As a consequence, on-resistance increases while EL signal shows a correlated decrease.

Small sized microfin tubes are a smart option to keep the refrigerant charge under the stricter and stricter values depicted by the new environmental laws. Despite of the large number of papers dedicated to phase change phenomena inside traditional microfin tubes with diameters larger than 5 mm, small sized microfin tubes are still a topic which deserves further studies. In this context, this paper proposes experimental results of heat transfer coefficients and frictional pressure drops collected during condensation of R1234ze(E) and R134a inside a small sized microfin tube with an outer diameter of 4.0 mm. Experimental tests were carried out for mass velocities from 100 to 1000 kg m−2 s−1, vapor qualities from 0.1 to 0.99, at saturation temperatures at the inlet of the test section of 30 °C and 40 °C. The range of working conditions permitted to better understand how each operative parameter affects the thermal and hydraulic behavior of the microfin tube during condensation heat transfer. The experimental results of heat transfer coefficient and frictional pressure drop were finally compared against values predicted by empirical correlations available in the open literature.