71 research outputs found

    Feasibility study and design of a low-energy residential unit in Sagarmatha park for environmental impact reduction of high altitude buildings

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    The project presented in this paper is geographically set within Sagarmatha National Park, a wide area located on the Nepalese mountainside of Everest and declared as World Heritage Site since 1979. In recent years the park was the focus of several studies and initiatives, aimed at improving the management of its many-sided ecosystem, significantly influenced by climate change and increase of human activities and tourism, which occurred from the end of the 1970s, as well as by practices that are harmful both to human health and to our environment (e.g. burn up kerosene or animal excrements in order to obtain heat). Research work has focused on designing a residential unit that meets population needs, in terms of simplicity of realization, replicability, use of local materials, environmental compatibility and exploitation of available renewable energies. For this purpose a thorough analysis was conducted to identify the housing standard characteristic of reference context and Sherpa people, concerning indoor thermal comfort conditions, construction techniques, availability and skills of local workforce. Data necessary for the design phase were obtained through a collaboration with researchers of Ev-K2-CNR center, active at 5,050 meters a.s.l. in Nepal at the base of Mount Everest with a laboratory/observatory (known as the "Pyramid") for highaltitude meteorological studies since 1989. Climate conditions were registered by specific monitoring stations at certain times (2002-2008); during preliminary stage, these values were considered representative of the local context chosen for the project, that is Namche Bazar, a village located within the park, in a central point both from the logistic and altimetric/weather points of view. For the residential unit under investigation, two different constructive approaches were selected and compared: earthbags and straw bales. Both techniques have several advantages, in particular availability of raw material (jute bags, soil, straw), simplicity (e.g. earthbag constructions are realized using the ancient technique of pisé, combined with flexible bags or tubes), durability, insulation performance, costeffectiveness. Through a specific software for calculation of winter/summer thermal loads, different combinations of selections of structure and insulation were examined for both solutions, in order to achieve the optimum for the case study. Furthermore on the base of data monitored on site, a specific assessment was carried out to evaluate the potential of solar and wind resources. Aiming at entirely covering the heat and electric energy needs by exploiting renewable energy sources, various plant configurations were finally assumed. Every single choice was made to reduce human influence on land resources, such as timber, and to improve internal and external environmental quality

    Three-year observations of halocarbons at the Nepal Climate Observatory at Pyramid (NCO-P, 5079 m a.s.l.) on the Himalayan range

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    A monitoring programme for halogenated climate-altering gases has been established in the frame of the SHARE EV-K<sup>2</sup>-CNR project at the Nepal Climate Laboratory – Pyramid in the Himalayan range at the altitude of 5079 m a.s.l. The site is very well located to provide important insights on changes in atmospheric composition in a region that is of great significance for emissions of both anthropogenic and biogenic halogenated compounds. Measurements are performed since March 2006, with grab samples collected on a weekly basis. The first three years of data have been analysed. After the identification of the atmospheric background values for fourteen halocarbons, the frequency of occurrence of pollution events have been compared with the same kind of analysis for data collected at other global background stations. The analysis showed the fully halogenated species, whose production and consumption are regulated under the Montreal Protocol, show a significant occurrence of "above the baseline" values, as a consequence of their current use in the developing countries surrounding the region, meanwhile the hydrogenated gases, more recently introduced into the market, show less frequent spikes. <br><br> Atmospheric concentration trends have been calculated as well, and they showed a fast increase, ranging from 5.7 to 12.6%, of all the hydrogenated species, and a clear decrease of methyl chloroform (−17.7%). The comparison with time series from other stations has also allowed to derive Meridional gradients, which are absent for long living well mixed species, while for the more reactive species, the gradient increases inversely with respect to their atmospheric lifetime. The effect of long range transport and of local events on the atmospheric composition at the station has been analysed as well, allowing the identification of relevant source regions the Northern half of the Indian sub-continent. Also, at finer spatial scales, a smaller, local contribution of forest fires from the Khumbu valley has been detected

    Using daily air temperature thresholds to evaluate snow melting occurrence and amount on Alpine glaciers by T-index models : the case study of the Forni Glacier

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    Glacier melt conditions (i.e., null surface temperature and positive energy budget) can be assessed by analyzing data acquired by a supraglacial automatic weather station (AWS), such as the station installed on the surface of Forni Glacier (Italian Alps). When an AWS is not present, the assessment of actual melt conditions and the evaluation of the melt amount is more difficult and simple methods based on T-index (or degree days) models are generally applied. These models require the choice of a correct temperature threshold. In fact, melt does not necessarily occur at daily air temperatures higher than 0 \ub0C. In this paper, we applied both energy budget and T-index approaches with the aim of solving this issue. We start by distinguishing between the occurrence of snowmelt and the reduction in snow depth due to actual ablation (from snow depth data recorded by a sonic ranger). Then we find the daily average temperature thresholds (by analyzing temperature data acquired by an AWS on Forni Glacier) which, on the one hand, best capture the occurrence of significant snowmelt conditions and, on the other, make it possible, using the T-index, to quantify the actual snow ablation amount. Finally we investigated the applicability of the mean tropospheric lapse rate to reproduce air temperature conditions at the glacier surface starting from data acquired by weather stations located outside the glacier area. We found that the mean tropospheric lapse rate allows for a good and reliable reconstruction of glacier air temperatures and that the choice of an appropriate temperature threshold in T-index models is a very important issue. From our study, the application of the +0.5 \ub0C temperature threshold allows for a consistent quantification of snow ablation while, instead, for detecting the beginning of the snow melting processes a suitable threshold has proven to be at least 124.6 \ub0C

    Improving the quality of cognitive screening assessments: ACEmobile, an iPad-based version of the Addenbrooke's Cognitive Examination-III.

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    INTRODUCTION: Ensuring reliable administration and reporting of cognitive screening tests are fundamental in establishing good clinical practice and research. This study captured the rate and type of errors in clinical practice, using the Addenbrooke's Cognitive Examination-III (ACE-III), and then the reduction in error rate using a computerized alternative, the ACEmobile app. METHODS: In study 1, we evaluated ACE-III assessments completed in National Health Service (NHS) clinics (n = 87) for administrator error. In study 2, ACEmobile and ACE-III were then evaluated for their ability to capture accurate measurement. RESULTS: In study 1, 78% of clinically administered ACE-IIIs were either scored incorrectly or had arithmetical errors. In study 2, error rates seen in the ACE-III were reduced by 85%-93% using ACEmobile. DISCUSSION: Error rates are ubiquitous in routine clinical use of cognitive screening tests and the ACE-III. ACEmobile provides a framework for supporting reduced administration, scoring, and arithmetical error during cognitive screening

    Preliminary Estimation of Black Carbon Deposition from Nepal Climate Observatory-Pyramid Data and Its Possible Impact on Snow Albedo Changes Over Himalayan Glaciers During the Pre-Monsoon Season

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    The possible minimal range of reduction in snow surface albedo due to dry deposition of black carbon (BC) in the pre-monsoon period (March-May) was estimated as a lower bound together with the estimation of its accuracy, based on atmospheric observations at the Nepal Climate Observatory-Pyramid (NCO-P) sited at 5079 m a.s.l. in the Himalayan region. We estimated a total BC deposition rate of 2.89 g m-2 day-1 providing a total deposition of 266 micrograms/ square m for March-May at the site, based on a calculation with a minimal deposition velocity of 1.0 10(exp -4) m/s with atmospheric data of equivalent BC concentration. Main BC size at NCO-P site was determined as 103.1-669.8 nm by correlation analysis between equivalent BC concentration and particulate size distribution in the atmosphere. We also estimated BC deposition from the size distribution data and found that 8.7% of the estimated dry deposition corresponds to the estimated BC deposition from equivalent BC concentration data. If all the BC is deposited uniformly on the top 2-cm pure snow, the corresponding BC concentration is 26.0-68.2 microgram/kg assuming snow density variations of 195-512 kg/ cubic m of Yala Glacier close to NCO-P site. Such a concentration of BC in snow could result in 2.0-5.2% albedo reductions. From a simple numerical calculations and if assuming these albedo reductions continue throughout the year, this would lead to a runoff increases of 70-204 mm of water drainage equivalent of 11.6-33.9% of the annual discharge of a typical Tibetan glacier. Our estimates of BC concentration in snow surface for pre-monsoon season can be considered comparable to those at similar altitude in the Himalayan region, where glaciers and perpetual snow region starts in the vicinity of NCO-P. Our estimates from only BC are likely to represent a lower bound for snow albedo reductions, since a fixed slower deposition velocity was used and atmospheric wind and turbulence effects, snow aging, dust deposition, and snow albedo feedbacks were not considered. This study represents the first investigation about BC deposition on snow from atmospheric aerosol data in Himalayas and related albedo effect is especially the first track at the southern slope of Himalayas

    Aerosol mass and black carbon concentrations, a two year record at NCO-P (5079 m, Southern Himalayas)

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    Aerosol mass and the absorbing fraction are important variables, needed to constrain the role of atmospheric particles in the Earth radiation budget, both directly and indirectly through CCN activation. In particular, their monitoring in remote areas and mountain sites is essential for determining source regions, elucidating the mechanisms of long range transport of anthropogenic pollutants, and validating regional and global models. Since March 2006, aerosol mass and black carbon concentration have been monitored at the Nepal Climate Observatory-Pyramid, a permanent high-altitude research station located in the Khumbu valley at 5079 m a.s.l. below Mt. Everest. The first two-year averages of PM<sub>1</sub> and PM<sub>1−10</sub> mass were 1.94 ÎŒg m<sup>−3</sup> and 1.88 ÎŒg m<sup>−3</sup>, with standard deviations of 3.90 ÎŒg m<sup>−3</sup> and 4.45 ÎŒg m<sup>−3</sup>, respectively, while the black carbon concentration average is 160.5 ng m<sup>−3</sup>, with a standard deviation of 296.1 ng m<sup>−3</sup>. Both aerosol mass and black carbon show well defined annual cycles, with a maximum during the pre-monsoon season and a minimum during the monsoon. They also display a typical diurnal cycle during all the seasons, with the lowest particle concentration recorded during the night, and a considerable increase during the afternoon, revealing the major role played by thermal winds in influencing the behaviour of atmospheric compounds over the high Himalayas. The aerosol concentration is subject to high variability: in fact, as well as frequent "background conditions" (55% of the time) when BC concentrations are mainly below 100 ng m<sup>−3</sup>, concentrations up to 5 ÎŒg m<sup>−3</sup> are reached during some episodes (a few days every year) in the pre-monsoon seasons. The variability of PM and BC is the result of both short-term changes due to thermal wind development in the valley, and long-range transport/synoptic circulation. At NCO-P, higher concentrations of PM<sub>1</sub> and BC are mostly associated with regional circulation and westerly air masses from the Middle East, while the strongest contributions of mineral dust arrive from the Middle East and regional circulation, with a special contribution from North Africa and South-West Arabian Peninsula in post-monsoon and winter season

    Accuracy of P0.1 measurements performed by ICU ventilators: a bench study.

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    Occlusion pressure at 100 ms (P0.1), defined as the negative pressure measured 100 ms after the initiation of an inspiratory effort performed against a closed respiratory circuit, has been shown to be well correlated with central respiratory drive and respiratory effort. Automated P0.1 measurement is available on modern ventilators. However, the reliability of this measurement has never been studied. This bench study aimed at assessing the accuracy of P0.1 measurements automatically performed by different ICU ventilators. Five ventilators set in pressure support mode were tested using a two-chamber test lung model simulating spontaneous breathing. P0.1 automatically displayed on the ventilator screen (P0.1 <sub>vent</sub> ) was recorded at three levels of simulated inspiratory effort corresponding to P0.1 of 2.5, 5 and 10 cm H <sub>2</sub> O measured directly at the test lung and considered as the reference values of P0.1 (P0.1 <sub>ref</sub> ). The pressure drop after 100 ms was measured offline on the airway pressure-time curves recorded during the automated P0.1 measurements (P0.1 <sub>aw</sub> ). P0.1 <sub>vent</sub> was compared to P0.1 <sub>ref</sub> and to P0.1 <sub>aw</sub> . To assess the potential impact of the circuit length, P0.1 were also measured with circuits of different lengths (P0.1 <sub>circuit</sub> ). Variations of P0.1 <sub>vent</sub> correlated well with variations of P0.1 <sub>ref</sub> . Overall, P0.1 <sub>vent</sub> underestimated P0.1 <sub>ref</sub> except for the Löwenstein <sup>Âź</sup> ventilator at P0.1 <sub>ref</sub> 2.5 cm H <sub>2</sub> O and for the Getinge group <sup>Âź</sup> ventilator at P0.1 <sub>ref</sub> 10 cm H <sub>2</sub> O. The agreement between P0.1 <sub>vent</sub> and P0.1 <sub>ref</sub> assessed with the Bland-Altman method gave a mean bias of - 1.3 cm H <sub>2</sub> O (limits of agreement: 1 and - 3.7 cm H <sub>2</sub> O). Analysis of airway pressure-time and flow-time curves showed that all the tested ventilators except the Getinge group <sup>Âź</sup> ventilator performed an occlusion of at least 100 ms to measure P0.1. The agreement between P0.1 <sub>vent</sub> and P0.1 <sub>aw</sub> assessed with the Bland-Altman method gave a mean bias of 0.5 cm H <sub>2</sub> O (limits of agreement: 2.4 and - 1.4 cm H <sub>2</sub> O). The circuit's length impacted P0.1 measurements' values. A longer circuit was associated with lower P0.1 <sub>circuit</sub> values. P0.1 <sub>vent</sub> relative changes are well correlated to P0.1 <sub>ref</sub> changes in all the tested ventilators. Accuracy of absolute values of P0.1 <sub>vent</sub> varies according to the ventilator model. Overall, P0.1 <sub>vent</sub> underestimates P0.1 <sub>ref</sub> . The length of the circuit may partially explain P0.1 <sub>vent</sub> underestimation

    A simple model to evaluate ice melt over the ablation area of glaciers in the Central Karakoram National Park, Pakistan

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    This study provides an estimate of fresh water derived from ice melt for the ablation areas of glaciers in the Central Karakoram National Park (CKNP), Pakistan. In the CKNP there are ~700 glaciers, covering ~4600 km2, with widespread debris cover (518 km2). To assess meltwater volume we applied a distributed model able to describe both debris-covered and debris-free ice ablation. The model was calibrated using data collected in the field in the CKNP area and validated by comparison with ablation data collected in the field, independent of the data used in building the model. During 23 July\u20139 August 2011, the mean model-estimated ablation in the CKNP was 0.024 m w.e./ d in debris covered areas and 0.037 m w.e./ d in debris-free areas. We found a mean error of +0.01 m w.e. (corresponding to 2%) and a root-mean-square error equal to 0.09 m w.e. (17%). According to our model, the ablation areas of all the glaciers in the CKNP produced a water volume of 1.963 km3 during the study period. Finally, we performed several sensitivity tests for assessing the impact of the input data variations
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