913 research outputs found

    Status of water use and potential of rainwater harvesting for replacing centralized supply system in remote mountainous areas: a case study.

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    The failure of the centralized water supply system forced XY community to become more dependent on uncertain and unstable water sources. The results of surveying 50 households showed that 89.18% of total households depended on water collected from rivers, which contributed 58.3% of the total water volume used for the domestic demands. The average water volume consumed was 19.5 liters/person/day (l/p/d), and 86.5% of households used more than one source; 13.5% of households collected water only from rivers, and 45.94% of families had rainwater harvesting (RWH) for their activities (domestic water demand); however, RWH only provided 9.9% of total water consumption. In this study, basic methods were applied to calculate the storage tanks necessary to balance the water deficit created by drought months. Three levels of water demand (14, 20, and 30 l/p/d) can be the best choices for RWH; for a higher demand (40 and 60 l/p/d), small roof area (30-40 m2), and many people (six to seven) per family, RWH might be impractical because of unsuitable rainfall or excessively large storage tanks

    ZFOURGE: Extreme 5007A˚\AA emission may be a common early-lifetime phase for star-forming galaxies at z>2.5z > 2.5

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    Using the \prospector\ spectral energy distribution (SED) fitting code, we analyze the properties of 19 Extreme Emission Line Galaxies (EELGs) identified in the bluest composite SED in the \zfourge\ survey at 2.5z42.5 \leq z \leq 4. \prospector\ includes a physical model for nebular emission and returns probability distributions for stellar mass, stellar metallicity, dust attenuation, and nonparametric star formation history (SFH). The EELGs show evidence for a starburst in the most recent 50 Myr, with the median EELG having a specific star formation rate (sSFR) of 4.6 Gyr1^{-1} and forming 15\% of its mass in this short time. For a sample of more typical star-forming galaxies (SFGs) at the same redshifts, the median SFG has a sSFR of 1.1 Gyr1^{-1} and forms only 4%4\% of its mass in the last 50 Myr. We find that virtually all of our EELGs have rising SFHs, while most of our SFGs do not. From our analysis, we hypothesize that many, if not most, star-forming galaxies at z2.5z \geq 2.5 undergo an extreme Hβ\beta+[\hbox{{\rm O}\kern 0.1em{\sc iii}}] emission line phase early in their lifetimes. In a companion paper, we obtain spectroscopic confirmation of the EELGs as part of our {\sc MOSEL} survey. In the future, explorations of uncertainties in modeling the UV slope for galaxies at z>2z>2 are needed to better constrain their properties, e.g. stellar metallicities.Comment: 11 pages, 5 figures (main figure is fig 5), accepted for publication in Ap

    Comparative study about the performance of three types of modified natural treatment systems for rice noodle wastewater

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    © 2019 Elsevier Ltd In this study, three semi-pilot scale systems (vertical flow constructed wetland, multi-soil layering, and integrated hybrid systems) for treating real rice noodle wastewater were operated parallelly for the first time in a tropical climate at a loading rate of 50 L/(m2·d) for more than 7 months to determine the optimal conditions and to compare their treatment performance. The results demonstrated that these systems were appropriate for the removal of organics, suspended solids, and total coliform (Tcol). The highest reductions in chemical oxygen demand (CODCr, 73.2%), phosphorus (PO4-P, 54%), and Tcol (4.78 log MPN/100 mL inactivation) were obtained by the integrated hybrid system, while the highest removal efficiencies of ammonium (NH4-N, 60.64%) and suspended solids (80.49%) were achieved in the vertical-flow-constructed wetland and multi-soil layering systems respectively

    Dry semi-continuous anaerobic digestion of food waste in the mesophilic and thermophilic modes: New aspects of sustainable management and energy recovery in South Korea

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    © 2016 Elsevier Ltd In this study, parallel, bench-scale, mesophilic and thermophilic, dry, semi-continuous anaerobic digestion (DScAD) of Korea food waste (FW, containing 22% total solids (TS) and 20% volatile solids (VS)) was investigated thoroughly under varying operational conditions, including hydraulic retention times (HRTs) and organic loading rates (OLRs). The aim was to evaluate the start-up, stability, overall removal efficiency, and inhibitory effects of toxic compounds on process performance over a long-term operation lasting 100 days. The results from both digesters indicate that the simultaneous reduction of VS and the production of gas improved as the HRT decreased or the OLR increased. The highest average rates of VS reduction (79.67%) and biogas production (162.14 m3biogas/ton of FW, 61.89% CH4), at an OLR of 8.62 ± 0.34 kg VS/m3day (25 days of HRT), were achieved under thermophilic DScAD. In addition, the average rates of reduction of VS and the production of biogas in thermophilic DScAD were higher by 6.88% and 16.4%, respectively, than were those in mesophilic DScAD. The inhibitory effects of ammonia, H2S, and volatile fatty acids (VFAs) on methane production was not clear from either of the digesters, although, apparently, their concentrations did fluctuate. This fluctuation could be attributed to the self-adaptation of the microbial well. However, digestion that was more stable and faster was observed under thermophilic conditions compared with that under mesophilic conditions. Based on our results, the optimum operational parameters to improve FW treatment and achieve higher energy yields could be determined, expanding the application of DScAD in treating organic wastes

    "First pain" in humans: convergent and specific forebrain responses

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    <p>Abstract</p> <p>Background</p> <p>Brief heat stimuli that excite nociceptors innervated by finely myelinated (Aδ) fibers evoke an initial, sharp, well-localized pain ("first pain") that is distinguishable from the delayed, less intense, more prolonged dull pain attributed to nociceptors innervated by unmyelinated (C) fibers ("second pain"). In the present study, we address the question of whether a brief, noxious heat stimulus that excites cutaneous Aδ fibers activates a distinct set of forebrain structures preferentially in addition to those with similar responses to converging input from C fibers. Heat stimuli at two temperatures were applied to the dorsum of the left hand of healthy volunteers in a functional brain imaging (fMRI) paradigm and responses analyzed in a set of volumes of interest (VOI).</p> <p>Results</p> <p>Brief 41°C stimuli were painless and evoked only C fiber responses, but 51°C stimuli were at pain threshold and preferentially evoked Aδ fiber responses. Most VOI responded to both intensities of stimulation. However, within volumes of interest, a contrast analysis and comparison of BOLD response latencies showed that the bilateral anterior insulae, the contralateral hippocampus, and the ipsilateral posterior insula were preferentially activated by painful heat stimulation that excited Aδ fibers.</p> <p>Conclusions</p> <p>These findings show that two sets of forebrain structures mediate the initial sharp pain evoked by brief cutaneous heat stimulation: those responding preferentially to the brief stimulation of Aδ heat nociceptors and those with similar responses to converging inputs from the painless stimulation of C fibers. Our results suggest a unique and specific physiological basis, at the forebrain level, for the "first pain" sensation that has long been attributed to Aδ fiber stimulation and support the concept that both specific and convergent mechanisms act concurrently to mediate pain.</p

    Adsorption mechanism of hexavalent chromium onto layered double hydroxides-based adsorbents: A systematic in-depth review

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    © 2019 Elsevier B.V. An attempt has been made in this review to provide some insights into the possible adsorption mechanisms of hexavalent chromium onto layered double hydroxides-based adsorbents by critically examining the past and present literature. Layered double hydroxides (LDH) nanomaterials are typical dual-electronic adsorbents because they exhibit positively charged external surfaces and abundant interlayer anions. A high positive zeta potential value indicates that LDH has a high affinity to Cr(VI) anions in solution through electrostatic attraction. The host interlayer anions (i.e., Cl−, NO3−, SO42−, and CO32−) provide a high anion exchange capacity (53–520 meq/100 g) which is expected to have an excellent exchangeable capacity to Cr(VI) oxyanions in water. Regarding the adsorption-coupled reduction mechanism, when Cr(VI) anions make contact with the electron-donor groups in the LDH, they are partly reduced to Cr(III) cations. The reduced Cr(III) cations are then adsorbed by LDH via numerous interactions, such as isomorphic substitution and complexation. Nonetheless, the adsorption-coupled reduction mechanism is greatly dependent on: (1) the nature of divalent and trivalent salts utilized in LDH preparation, and the types of interlayer anions (i.e., guest intercalated organic anions), and (3) the adsorption experiment conditions. The low Brunauer–Emmett–Teller specific surface area of LDH (1.80–179 m2/g) suggests that pore filling played an insignificant role in Cr(VI) adsorption. The Langmuir maximum adsorption capacity of LDH (Qomax) toward Cr(VI) was significantly affected by the natures of used inorganic salts and synthetic methods of LDH. The Qomax values range from 16.3 mg/g to 726 mg/g. Almost all adsorption processes of Cr(VI) by LDH-based adsorbent occur spontaneously (ΔG° 0) and increase the randomness (ΔS° >0) in the system. Thus, LDH has much potential as a promising material that can effectively remove anion pollutants, especially Cr(VI) anions in industrial wastewater

    Remote monitoring of natural slopes. Insights from the first Terrestrial INSAR campaign In Vietnam

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    Il presente lavoro, realizzato nell'ambito di un progetto di ricerca finanziato dal Vietnamese Space Science &amp; Technology Program, mostra i primi risultati di una campagna di monitoraggio da remoto della frana di Nam Dan (Vietnam settentrionale) dove, per la prima volta nel Paese, è stata utilizzata la tecnica dell'Interferometria SAR Terrestre (TInSAR). Tale tecnica si basa sull’utilizzo di un sensore radar installato su una piattaforma terrestre che trasmette il segnale nel campo delle microonde (banda Ku) e ne riceve gli echi di ritorno dai target riflettenti. Il sensore utilizzato è costituito da due antenne (una trasmittente e una ricevente) e si muove seguendo una traiettoria lineare lungo un binario. Grazie a questa tecnica è possibile effettuare da remoto il monitoraggio delle deformazioni del terreno, raggiungendo una precisione sub-millimetrica in condizioni ideali (ad es. breve distanza, alta riflettività, etc.). Le attività di monitoraggio sono state condotte nel villaggio di Nam Dan, dove una frana attiva con diverse evidenze geomorfologiche quali scarpate, crepe, contropendenze con ristagni d’acqua, abitazioni e beni pubblici gravemente danneggiati, costituisce una seria minaccia per la popolazione locale. L’area di Nam Dan (22°36'N; 104°29'E) si trova nella parte meridionale del distretto di Xin Man, in prossimità del confine tra Vietnam e Cina. Tale distretto, caratterizzato da un clima monsonico umido subtropicale, si estende su un'area di circa 582 km2ed è caratterizzato da una topografia complessa con catene montuose, pendii terrazzati e valli molto profonde con processi erosivi avanzati. Gli archivi locali riportano che in tale area, dal 2012 al 2016, si sono verificate 967 frane, principalmente durante l'estate in corrispondenza delle piogge monsoniche del sud-ovest. Secondo recenti indagini e osservazioni sul campo, la frana oggetto di studio, verificatasi nel luglio del 2012 in seguito a forti precipitazioni, può classificarsi come uno scivolamento traslativo di detrito e si estende su un'area di circa 12.000 m2 con una profondità media di circa 22,5 metri. Nell'agosto del 2013 la frana ha causato nuovi gravi danni a 5 abitazioni, al mercato comunale e alla strada provinciale n. 178 e rappresenta tutt’oggi un grave pericolo per la popolazione residente. Le attività di monitoraggio sono state effettuate tra agosto e dicembre 2019 attraverso un nuovo interferometro radar denominato Phoenix, che è stato utilizzato in una delle sue prime applicazioni sul campo. Il monitoraggio tramite Interferometria SAR Terrestre ha avuto l’obiettivo di controllare l’evoluzione del versante instabile ed ha portato alla realizzazione di mappe di spostamento e delle relative serie temporali, fornendo informazioni dettagliate sulla localizzazione e sui tassi di deformazione dei processi gravitativi di versante presenti. Sebbene nel periodo monitorato non siano state registrate deformazioni significative, l'utilizzo di questa tecnica di telerilevamento, insieme alla strumentazione a contatto precedentemente installata (inclinometri, piezometri, pluviometri) ed alle indagini sul campo, hanno contribuito a migliorare la conoscenza della frana di Nam Dan e la comprensione del suo cinematismo, con particolare riguardo all'evoluzione temporale delle deformazioni superficiali, anche tenendo conto delle condizioni meteorologiche locali. I risultati ottenuti durante la campagna di monitoraggio, in combinazione con i dati precedentemente acquisiti ed elaborati, confermano che il versante oggetto di studio è caratterizzato da fenomeni di instabilità gravitativa, che possono essere innescati da precipitazioni intense che solitamente avvengono nell’area durante la stagione estiva. In considerazione dei contesti ambientali dell'area, quali le severe condizioni climatiche e le aree impervie da percorrere in assenza di infrastrutture viarie adeguate, è stato posto l'accento sulle attività operative sul campo e sull'individuazione di soluzioni tecnologiche appropriate, che hanno rappresentato aspetti particolarmente sfidanti per il monitoraggio di fenomeni franosi tramite tecniche di telerilevamento.The present work, realized in the framework of a research project funded by the Vietnamese Space Science &amp; Technology Program, shows the first insights of remote monitoring at the Nam Dan landslide (Northern Vietnam). The Terrestrial SAR Interferometry (TInSAR) technique was used for the first time in the Country.The activities were performed in Nam Dan village, where an active landslide with several geomorphological evidences as open cracks and scarps, severely damaged dwellings and public assets, constituting a serious hazard to the local inhabitants. The monitoring activities were carried out between August and December 2019 through a new TInSAR device called Phoenix which it was used for one of its first on-field applications. The Terrestrial SAR was aimed at creating displacement maps and related time series, providing detailed information on the location and deformation rate of the processes under investigation. The use of such a remote sensing technique, coupled with contact instrumentation (inclinometers, piezometers, rain gauge) and field surveys have contributed to improving the knowledge about the Nam Dan landslide and the understanding of its behaviour, with particular regard to the time evolution of deformations

    Use of Oral Cholera Vaccines in an Outbreak in Vietnam: A Case Control Study

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    Simple measures such as adequate sanitation and clean water stops the spread of cholera; however, in areas where these are not available, cholera spreads quickly and may lead to death in a few hours if treatment is not initiated immediately. The use of life-saving rehydration therapy is the mainstay in cholera control, however, the rapidity of the disease and the limited access to appropriate healthcare units in far-flung areas together result in an unacceptable number of deaths. The WHO has recommended the use of oral cholera vaccines as a preventive measure against cholera outbreaks since 2001, but this was recently updated so that vaccine use may also be considered once a cholera outbreak has begun. The findings from this study suggest that reactive use of killed oral cholera vaccines provides protection against the disease and may be a potential tool in times of outbreaks. Further studies must be conducted to confirm these findings
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