2,302 research outputs found

    Cementation in a matrix of loose sandy soil using biological treatment method

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    Man-made materials varying from cement-based to chemical-based have been injected into soils to improve their engineering properties (shear strength, compressibility, permeability, bearing capacity etc.). Soil type in general plays important role in determination of treatment material and method. Materials used for soil treatment might have side effects in terms of air pollution, soil or water contamination etc. during manufacturing or application. An alternative, environmentally friendly soil treatment method that is based on the use of bacteria present in soils and named Biological Treatment Method (BTM) has been used by researchers to bond particles of loose sandy soils via creation of calcite (CaCO3) generated by bacteria using urea to influence the precipitation of calcium carbonate. This study presents the results of bacterial induced cementation (BIC) in matrix of loose sandy soil. A bacterium used in this study is Sporosarcina pasteurii that is naturally present in soils and is aerobic type. The bacteria grown in laboratory environment were injected to the matrix of loose sandy soil. Subsequent nutrient mediums were introduced to specimens to accelerate the development of cementation level. Number of bacteria, pH level, temperature and amount of CaCO3 were measured during the duration of testing. Images of Scanning Electron Microscope (SEM) showed that creation of cementation from precipitation of CaCO3 on the surface and pores of soil matrix were observed for only sand samples into which nutrient was flushed on sequence of arbitrary time.Key words: Biological treatment, sand, soil treatment

    The effectiveness of Sufi music for mental health outcomes. A systematic review and meta-analysis of 21 randomised trials.

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    BACKGROUND: There is some evidence that Sufi music therapy might improve physical and mental well-being; however, no systematic review or meta-analysis has pooled and critiqued the evidence. The aim of this systematic review was to evaluate the effects of Sufi music therapy on mental health outcomes. METHODS: We searched Medline, PsycINFO, the Web of Science, Science Direct, PsycARTICLES, Cochrane Library, SCOPUS, CINAHL Plus, AMED, and ULAKBIM databases, and the reference lists of the studies found. Papers published in academic peer-reviewed journals were included, as well as from other sources such as chapters in edited books, the grey literature, or conference presentations. Articles published up to March 2020 in Turkish and English were included. Our primary outcome of interest was anxiety and secondary outcomes of interest were other mental health outcomes such as depression. To assess the methodological quality of the articles, the Cochrane Risk of Bias Tool was used. The quality of evidence was assessed using the GRADEpro GDT system. RESULTS: This search yielded 21 clinical trials that were eligible for inclusion. A meta-analysis, using a random effects model, of 18 randomised controlled trials involving 1454 participants showed that Sufi music therapy with makams, compared with treatment as usual (TAU) or a no-music control group, reduced symptoms of anxiety in the short term in patients undergoing an operation or treatments such as chemotherapy or haemodialysis (standardised mean difference SMD= -1.15, 95% CI, -1.64 to -0.65; very low-quality evidence). The evidence of Sufi music with makam's effect on anxiety is rated as very low. Qualitative synthesis of secondary outcomes revealed significant effects for depression, positive symptoms in schizophrenia, stress, which however were based on fewer studies. Trials were of moderate methodological quality, and there was significant heterogeneity across the studies. CONCLUSION: Sufi music may reduce anxiety of patients undergoing medical procedures like haemodialysis, coronary artery surgery, angiography, colonoscopy, bone marrow aspiration and biopsy procedures. Evidence from single studies suggests effects on depression and stress as well. However, due to methodological limitations of the studies, further, higher quality studies are required in other cultures

    Characterization of an embedded RF-MEMS switch

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    An RF-MEMS capacitive switch for mm-wave integrated circuits, embedded in the BEOL of 0.25ÎĽm BiCMOS process, has been characterized. First, a mechanical model based on Finite-Element-Method (FEM) was developed by taking the residual stress of the thin film membrane into account. The pull-in voltage and the capacitance values obtained with the mechanical model agree very well with the measured values. Moreover, S-parameters were extracted using Electromagnetic (EM) solver. The data observed in this way also agree well with the experimental ones measured up to 110GHz. The developed RF model was applied to a transmit/receive (T/R) antenna switch design. The results proved the feasibility of using the FEM model in circuit simulations for the development of RF-MEMS switch embedded, single-chip multi-band RF ICs

    Gas and seismicity within the Istanbul seismic gap

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    Understanding micro-seismicity is a critical question for earthquake hazard assessment. Since the devastating earthquakes of Izmit and Duzce in 1999, the seismicity along the submerged section of North Anatolian Fault within the Sea of Marmara (comprising the “Istanbul seismic gap”) has been extensively studied in order to infer its mechanical behaviour (creeping vs locked). So far, the seismicity has been interpreted only in terms of being tectonic- driven, although the Main Marmara Fault (MMF) is known to strike across multiple hydrocarbon gas sources. Here, we show that a large number of the aftershocks that followed the M 5.1 earthquake of July, 25th 2011 in the western Sea of Marmara, occurred within a zone of gas overpressuring in the 1.5–5 km depth range, from where pressurized gas is expected to migrate along the MMF, up to the surface sediment layers. Hence, gas-related processes should also be considered for a complete interpretation of the micro- seismicity (~M < 3) within the Istanbul offshore domain

    Revealing the last 13,500 years of environmental history from the multiproxy record of a mountain lake (Lago Enol, northern Iberian Peninsula)

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    This is the author's accepted manuscript. The final publication is available at Springer via http://dx.doi.org/10.1007/s10933-009-9387-7.We present the Holocene sequence from Lago Enol (43°16′N, 4°59′W, 1,070 m a.s.l.), Cantabrian Mountains, northern Spain. A multiproxy analysis provided comprehensive information about regional humidity and temperature changes. The analysis included sedimentological descriptions, physical properties, organic carbon and carbonate content, mineralogy and geochemical composition together with biological proxies including diatom and ostracod assemblages. A detailed pollen study enabled reconstruction of variations in vegetation cover, which were interpreted in the context of climate changes and human impact. Four distinct stages were recognized for the last 13,500 years: (1) a cold and dry episode that includes the Younger Dryas event (13,500–11,600 cal. year BP); (2) a humid and warmer period characterizing the onset of the Holocene (11,600–8,700 cal. year BP); (3) a tendency toward a drier climate during the middle Holocene (8,700–4,650 cal. year BP); and (4) a return to humid conditions following landscape modification by human activity (pastoral activities, deforestation) in the late Holocene (4,650–2,200 cal. year BP). Superimposed on relatively stable landscape conditions (e.g. maintenance of well established forests), the typical environmental variability of the southern European region is observed at this site.The Spanish Inter-Ministry Commission of Science and Technology (CICYT), the Spanish National Parks agency, the European Commission, the Spanish Ministry of Science, and the European Social Fund
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