1,357 research outputs found

    Development of titanium dioxide nanoparticles/nanosolution for photocatalytic activity

    Get PDF
    Biological and chemical contaminants by man-made activities have been serious global issue. Exposure of these contaminants beyond the limits may result in serious environmental and health problem. Therefore, it is important to develop an effective solution that can be easily utilized by mankind. One of the effective ways to overcome this problem is by using titanium dioxide (TiO2). TiO2 is a well-known photocatalyst that widely used for environmental clean-up due to its ability to decompose organic pollutant and kill bacteria. Although it is proven TiO2 has an advantage to solve this concern, its usefulness unfortunately is limited only under UV light irradiation. Therefore, the aim of this work was to investigate the potential of TiO2 that can be activated under visible light by the incorporation of metal ions (Fe, Ag, Zr and Ag-Zr). In this study, sol-gel method was employed for the synthesis of metal ions incorporated TiO2. XRD analysis revealed that all samples content biphasic anatase-brookite TiO2 of size 3 nm to 5 nm. It was found that the incorporation of these metal ions did not change the morphology of TiO2 but the crystallinity and optical properties were affected. The crystallinity of anatase in the biphasic TiO2 was found to be decreased and favored brookite formation. PL analysis showed metal ions incorporation suppressed the recombination of electron-hole pairs while the band gap energy of TiO2 (3.2 eV) was decreased by the incorporation of Fe (2.46 eV) and Ag (2.86 eV). Among this incorporation, Ag-Zr incorporated TiO2 showed highest performance for methyl orange degradation (93%) under fluorescent xxv light irradiation for 10 h. This follows by Zr-TiO2 (82%), Fe-TiO2 (75%) and Ag�TiO2 (43%). Meanwhile, the highest antibacterial performance was exhibited by Ag�TiO2. TEM images showed that E.coli bacterium was killed within 12 h after treated with Ag-TiO2. The results obtained from the fieldwork study established that Ag-Zr incorporation have excellent performances for VOC removal and antibacterial test. The VOC content after treated with Ag-Zr-TiO2 fulfilled the Industry Code of Practice on Indoor Air Quality 2010 which is lower than 3 ppm. In addition, the percentage of microbes also found to be decrease around 45 % within 5 days of monitoring

    An energy-efficient clustering protocol using fuzzy logic and network segmentation for heterogeneous WSN

    Get PDF
    Wireless sensor networks have become an emerging research area due to their importance in the present industrial application. The enlargement of network lifetime is the major limitation in WSN. Several routing protocols study the extension of lifespan in WSN. Routing protocols significantly influence on the global of energy consumption for sensors in WSN. It is essential to correct the energy efficiency performance of routing protocol in order to improve the lifetime. The protocols based on clustering are the most routing protocols in WSN to reduce energy consumption. The protocols dedicate to WSN have demonstrated their limitation in expanding the lifetime of the network. In this paper, we present Hybrid SEP protocol : Multi-zonal Fuzzy logic heterogeneous Clustering based on Stable Election Protocol (FMZ-SEP). The FMZ-SEP characterizes by four parameters: WSN segmentation (splitting the WSN into the triangle zones ), the Subtractive Clustering Method to determine a correct number of clusters, the FCM and the SEP protocol. The FMZ-SEP prolong the stability period and extend the lifetime. The simulation results point out that the stability period of FMZ-SEP. FMZ-SEP protocol outperforms of MZ-SEP, FSEP and SEP protocol by improving the network lifetime and the stability period

    Use of laser interferometry for measuring concrete substrate roughness in patch repairs

    Get PDF
    The overall success and long-term durability of a patch repair is significantly influenced by the bond developed at the interface between the concrete substrate and the repair material. In turn, the bond strength is influenced by the topography (roughness) of the substrate surface after removal of the defective concrete. However, different removal methods of defective concrete produce substrate surfaces with different topographies. Hence, the ability to measure and characterise the topography of substrate surfaces is of great importance for evaluating the effectiveness of different removal methods. In this paper, the effect of two removal methods: electric chipping hammers and Remote Robotic Hydro-erosion (RRH) on the surface roughness is investigated through the use of a prototype non-contact (optical) laser interferometry measuring device. Laboratory results show that the above equipment can be used to characterise substrate roughness and confirm the ability of RRH to create rougher surfaces as opposed to chipping hammers

    Multiscale simulations of growth-dominated Sb2_2Te phase-change material for non-volatile photonic applications

    Get PDF
    Chalcogenide phase-change materials (PCMs) are widely applied in electronic and photonic applications, such as non-volatile memory and neuro-inspired computing. Doped Sb2_2Te alloys are now gaining increasing attention for on-chip photonic applications, due to their growth-driven crystallization features. However, it remains unknown whether Sb2_2Te also forms a metastable crystalline phase upon nanoseconds crystallization in devices, similar to the case of nucleation-driven Ge-Sb-Te alloys. Here, we carry out ab initio simulations to understand the changes in optical properties of amorphous Sb2_2Te upon crystallization and post annealing. During the continuous transformation process, changes in the dielectric function are highly wavelength-dependent from the visible-light range towards the telecommunication band. Our finite-difference time-domain simulations based on the ab initio input reveal key differences in device output for color display and photonic memory applications upon tellurium ordering. Our work serves as an example of how multiscale simulations of materials can guide practical photonic phase-change applications.Comment: 16 pages,8 figure

    Kyste hydatique du foie rompu dans la paroi abdominale et dans le muscle psoas : à propos d'une rare observation

    Get PDF
    Le kyste hydatique du foie est une parasitose qui sévit à l′état endémique au maroc. La rupture dans la paroi abdominale et dans le psoas est une complication exceptionnelle. Nous rapportons un cas de kyste hydatique du foie rompu dans la paroi et dans le muscle psoas. Le diagnostic a été établi sur les données de l′échographie et surtout de la tomodensitométrie. Le patient a été opéré avec des suites simples

    Metastatic myocardial abscess on the posterior wall of the left ventricle: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Myocardial abscess is a rare and potentially fatal condition. Metastatic myocardial abscess in the setting of infective endocarditis has been infrequently reported in the medical literature. To the best of the authors' knowledge no case of myocardial abscess affecting the free wall of the left ventricle secondary to infective endocarditis of a right-sided heart valve has been reported previously.</p> <p>Case presentation</p> <p>We report a case of tricuspid valve endocarditis caused by <it>Staphylococcus aureus </it>and resulting in a myocardial abscess on the posterior wall of the left ventricle, far from the active valvular infection. We also briefly discuss the role of different investigation modalities including cardiac magnetic resonance imaging in diagnosing myocardial abscess.</p> <p>Conclusion</p> <p>Myocardial abscess is a life-threatening illness. A high index of clinical suspicion is required to make a prompt diagnosis. Final diagnosis may need multi-modality imaging. An early diagnosis, aggressive medical therapy, multidisciplinary care and timely surgical intervention may save life in this otherwise fatal condition.</p

    Ventricular noncompaction in a female patient with nephropathic cystinosis: a case report

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>We report an unusual and interesting case of a 24-year-old woman with nephropathic cystinosis in association with concomitant isolated noncompaction of the left ventricle. Left ventricular noncompaction usually presents with reduced exercise tolerance as a consequence of ventricular dysfunction, the result of embolus or with palpitations and syncope due to arrhythmia. There is no specific treatment directed at isolated noncompaction. Treatment is focused on the cause of presentation, with medication aimed at improving ventricular dysfunction, as well as treating and preventing thrombosis and arrhythmia.</p> <p>Case presentation</p> <p>Our patient presented with an episode of decompensated heart failure. Trans-thoracic echocardiography demonstrated excessive trabeculation with inter-trabecular recesses in the left ventricle typical of noncompaction of the left ventricle. The patient's admission was complicated by a cardiac arrest precipitated by ventricular tachycardia for which she subsequently underwent implantation of an automatic implantable cardioverter defibrillator.</p> <p>Conclusion</p> <p>This is, as far as we know, the first case report of the co-existence of nephropathic cystinosis and isolated noncompaction of the left ventricle. It highlights the importance of being vigilant to the diagnosis of left ventricular noncompaction.</p

    Diversity, distribution and conservation of the terrestrial reptiles of Oman (Sauropsida, Squamata)

    Get PDF
    All authors: Salvador Carranza , Meritxell Xipell, Pedro Tarroso, Andrew Gardner, Edwin Nicholas Arnold, Michael D. Robinson, Marc Simó-Riudalbas, Raquel Vasconcelos, Philip de Pous, Fèlix Amat, Jiří Šmíd, Roberto Sindaco, Margarita Metallinou †, Johannes Els, Juan Manuel Pleguezuelos, Luis Machado, David Donaire, Gabriel Martínez, Joan Garcia-Porta, Tomáš Mazuch, Thomas Wilms, Jürgen Gebhart, Javier Aznar, Javier Gallego, Bernd-Michael Zwanzig, Daniel Fernández-Guiberteau, Theodore Papenfuss, Saleh Al Saadi, Ali Alghafri, Sultan Khalifa, Hamed Al Farqani, Salim Bait Bilal, Iman Sulaiman Alazri, Aziza Saud Al Adhoobi, Zeyana Salim Al Omairi, Mohammed Al Shariani, Ali Al Kiyumi, Thuraya Al Sariri, Ahmed Said Al Shukaili, Suleiman Nasser Al Akhzami.In the present work, we use an exceptional database including 5,359 records of 101 species of Oman’s terrestrial reptiles together with spatial tools to infer the spatial patterns of species richness and endemicity, to infer the habitat preference of each species and to better define conservation priorities, with especial focus on the effectiveness of the protected areas in preserving this unique arid fauna. Our results indicate that the sampling effort is not only remarkable from a taxonomic point of view, with multiple observations for most species, but also for the spatial coverage achieved. The observations are distributed almost continuously across the two-dimensional climatic space of Oman defined by the mean annual temperature and the total annual precipitation and across the Principal Component Analysis (PCA) of the multivariate climatic space and are well represented within 17 out of the 20 climatic clusters grouping 10% of the explained climatic variance defined by PC1 and PC2. Species richness is highest in the Hajar and Dhofar Mountains, two of the most biodiverse areas of the Arabian Peninsula, and endemic species richness is greatest in the Jebel Akhdar, the highest part of the Hajar Mountains. Oman’s 22 protected areas cover only 3.91% of the country, including within their limits 63.37% of terrestrial reptiles and 50% of all endemics. Our analyses show that large areas of the climatic space of Oman lie outside protected areas and that seven of the 20 climatic clusters are not protected at all. The results of the gap analysis indicate that most of the species are below the conservation target of 17% or even the less restrictive 12% of their total area within a protected area in order to be considered adequately protected. Therefore, an evaluation of the coverage of the current network of protected areas and the identification of priority protected areas for reptiles using reserve design algorithms are urgently needed. Our study also shows that more than half of the species are still pending of a definitive evaluation by the International Union for Conservation of Nature (IUCN).This work was funded by grants CGL2012-36970, CGL2015-70390-P from the Ministerio de Economía y Competitividad, Spain (cofunded by FEDER) to SC, the project Field study for the conservation of reptiles in Oman, Ministry of Environment and Climate Affairs, Oman (Ref: 22412027) to SC and grant 2014-SGR-1532 from the Secretaria d'Universitats i Recerca del Departament d'Economia i Coneixement de la Generalitat de Catalunya to SC. MSR is funded by a FPI grant from the Ministerio de Economía y Competitividad, Spain (BES-2013-064248); RV, PT and LM were funded by Fundação para a Ciência e Tecnologia (FCT) through post-doc grants (SFRH/BPD/79913/2011) to RV, (SFRH/BPD/93473/2013) to PT and PhD grant (SFRH/BD/89820/2012) to LM, financed by Programa Operacional Potencial Humano (POPH) – Quadro de Referência Estrategico Nacional (QREN) from the European Social Fund and Portuguese Ministerio da Educação e Ciência
    corecore