Numerical Modelling of Simultaneous Heat and Moisture Transport in Fire Protective Suits Under Flash Fire Exposure and Evaluation of Second Degree Burn Time

An improved numerical model is developed for coupled heat and moisture transport in fire protective suit exposed to flash fire. This model is combined with Pennes' bio-heat transfer model and subsequently, second-degree burn time is estimated using Henriques' burn integral. Natural convection is considered inside the air gap present between the multilayer clothing ensemble and the skin. Comparisons of temperature and moisture distribution within the multilayer clothing, air gap, and the skin during the exposure are presented considering combined heat and moisture transport and only heat transport. Effect of moisture transport on the protective performance of the fire protective suit is shown. Impact of both horizontal and vertical air gap orientations on second-degree burn time is studied. Effect of temperature-dependent thermo-physical properties, relative humidity, fiber regain, different exposure conditions and fabric combinations for the fire protective suits on burn time is analyzed.

Large-Scale Background and the Role of Quasi-Biweekly Moisture Transport in the Extreme Yangtze River Rainfall in Summer 2020

A severe flooding hit southern China along the Yangtze River in summer 2020. The floods were induced by heavy rains, and the associated dynamic and thermodynamic conditions are investigated using daily gridded rainfall data of China and NCEP-NCAR reanalysis. It is found that the summer rainfall over the Yangtze River Basin (YRB) experienced pronounced subseasonal variation in 2020, dominated by a quasi-biweekly oscillation (QBWO) mode. The southwestward-moving anomalous QBWO circulation was essentially the fluctuation of cold air mass related to the tropospheric polar vortex or trough-ridge activities over the mid-high latitude Eurasian in boreal summer. The large-scale southwestward-transport of cold air mass from mid-high latitudes and the northeastward-transport of warm and moist air by the strong anomalous anticyclone over the western North Pacific provided important circulation support for the heavy rainfall in the YRB. The quasi-biweekly anomalies of potential and divergent component of vertically integrated water vapor flux played a major role in maintaining the moisture during summer 2020. The diagnosis of moisture budget shows that the enhanced moisture associated with the quasi-biweekly fluctuation rainfall was primarily attributed to the moisture convergence. The convergence of QBWO specific humidity by the background mean flow and convergence of mean specific humidity by QBWO flow played dominant roles in contributing to the positive moisture tendency. In combination with an adiabatic ascent induced by the warm temperature advection, the boundary layer moisture convergence strengthens the upward transport of moisture from lower troposphere. The vertical moisture transport associated with boundary layer convergence was of critical importance in causing low-level tropospheric moistening, whereas the horizontal advection of moisture showed a negative effect during the anomalous quasi-biweekly summer rainfall in 2020.

Moisture origin, transport pathways, and driving processes of intense wintertime moisture transport into the Arctic

A substantial portion of the moisture transport into the Arctic occurs in episodic, high-amplitude events with strong impacts on the Arctic's climate system components such as sea ice. This study focuses on the origin of such moist-air intrusions during winter and examines the moisture sources, moisture transport pathways, and their linkage to the driving large-scale circulation patterns. For that purpose, 597 moist-air intrusions, defined as daily events of intense (exceeding the 90th anomaly percentile) zonal mean moisture transport into the polar cap (≥70∘ N), are identified. Kinematic backward trajectories combined with a Lagrangian moisture source diagnostic are then used to pinpoint the moisture sources and characterize the airstreams accomplishing the transport. The moisture source analyses show that the bulk of the moisture transported into the polar cap during these moist-air intrusions originates in the eastern North Atlantic with an uptake maximum poleward of 50∘ N. Trajectories further reveal an inverse relationship between moisture uptake latitude and the level at which moisture is injected into the polar cap, consistent with ascent of poleward-flowing air in a baroclinic atmosphere. Focusing on intrusions in the North Atlantic (424 intrusions), we find that lower tropospheric moisture transport is predominantly accomplished by two types of airstreams: (i) cold, polar air warmed and moistened by surface fluxes and (ii) air subsiding from the mid-troposphere into the boundary layer. Both airstreams contribute about 36 % each to the total transport. The former accounts for most of the moisture transport during intrusions associated with an anomalously high frequency of cyclones east of Greenland (218 intrusions), whereas the latter is more important in the presence of atmospheric blocking over Scandinavia and the Ural Mountains (145 events). Long-range moisture transport, accounting for 17 % of the total transport, dominates during intrusions with weak forcing by baroclinic weather systems (64 intrusions). Finally, mid-tropospheric moisture transport is invariably associated with (diabatically) ascending air and moisture origin in the central and western North Atlantic, including the Gulf Stream front, accounting for roughly 10 % of the total transport. In summary, our study shows that moist-air intrusions into the polar atmosphere result from a combination of airstreams with predominantly high-latitude or high-altitude origin, whose relative importance is determined by the underlying driving weather systems (i.e., cyclones and blocks).

Polylactic acid based Janus membranes with asymmetric wettability for directional moisture transport with enhanced UV protective capabilities

The PLA-E/TiO2@PDA–PLA Janus membrane with asymmetric wettability exhibits efficient directional moisture transport and excellent UV protective capacity.

Rainfall distribution in Yamuna catchment and quantitative estimation of heavy rainfall in related synoptic situations

A study of rainfall over Yamuna catchment from its origin upto Delhi for the period from 1976to 1990 IS made with an attempt to understand the fine distribution of rainfall in different ranges over the catch-ment for the flood operational period from .1 June to 15 October. The study of associated synoptic situations for heavy rainfall activity in the catchment is made for synoptic typing. Synoptic empirical diagrams have been developed for estimation of average isohyetal rainfall over the catchment from estimation of moisture transport.

Antarctic Peninsula warming and precipitation phase transition during atmospheric river events

<p><span lang="en-US">Polar amplification has been pronounced in the Arctic with near-surface air temperatures increasing at more than twice the global warming rate d</span>uring the last several decades<span lang="en-US">. At the same time, over Antarctica temperature trends have exhibited a large regional variability. In particular, the </span>Antarctic Peninsula (AP) <span lang="en-US">stands out as having a </span>warming<span lang="en-US"> rate much higher than</span> the rest of the Antarctic ice sheet and other land areas in the Southern Hemisphere (SH)<span lang="en-US">.</span> <span lang="en-US">F</span>uture projections indicate that <span lang="en-US">warming and ice loss will intensify in both polar regions with important impacts</span> globally. In addition to the warming amplification, there has been also an enhancement of the polar water cycle with increase<span lang="en-US">s</span> <span lang="en-US">in </span>poleward moisture transport and precipitation in both polar regions. An important process linking warming and precipitation enhancement is a shift towards more frequent rainfall compared to snowfall<span lang="en-US">. F</span>uture projections show that the rain fraction will significantly increase in coastal Antarctica, especially in the AP. Atmospheric rivers (ARs), long corridors of intense moisture transport from subtropical and mid-latitude regions poleward, are known for <span lang="en-US">their </span>prominent role in <span lang="en-US">both </span>heat and moisture transport with impacts ranging from intense precipitation to temperature records and major melt events in Antarctica.<span lang="en-US"> Limited observations have hampered process understanding and correct representation of these extreme events in models.</span> <span lang="en-US">This presentation will give an overview of the </span>enhanced observations targeting ARs in the A<span lang="en-US">P</span> (<span lang="en-US">including </span>surface meteorology, radiosonde, cloud and precipitation remote sensing, <span lang="en-US">and </span>radiative fluxes) as part of the <span lang="en-US">Year of Polar Prediction (</span>YOPP<span lang="en-US">)</span>-SH international collaborative effort<span lang="en-US">. </span>In-depth analysis of transport of heat and moisture, <span lang="en-US">atmospheric vertical structure, </span>cloud properties<span lang="en-US"> and precipitation phase transition from snowfall to rainfall </span>during selected <span lang="en-US">AR </span>case<span lang="en-US">s</span> will be<span lang="en-US"> presented and compared with ERA5 reanalysis and high-resolution Polar-WRF model simulations</span>.<span lang="en-US"> We will highlight three different local regimes around the AP: large-scale precipitation over the Southern Ocean north of the AP, orographic enhancement of precipitation in the western AP and the role of foehn, cloud/precipitation clearing and temperature increase in the northeastern AP. </span></p>

Utilization of Crushed Pavement Blocks in Concrete: Assessment of Functional Properties and Environmental Impacts

Production of concrete is connected to extensive energy demands, greenhouse gases production or primary sources depletion. Reflecting current economical, social, or environmental trends, there is strong pressure on mitigation these requirements and impacts. The exploitation of secondary- or waste materials in production processes has therefore a great potential which is not related solely to binders but also to fillers. In this light, this paper aims at thorough investigations of concrete mixtures with crushed concrete pavements as partial or full replacement of natural coarse aggregates. The research combines experimental techniques to quantify the influence of the substitution on basic physical, mechanical, and heat/moisture transport/storage parameters. The experimental data obtained are further exploited as input data for computational prediction of coupled heat and moisture transport to assess the influence of the aggregates substitution on hygrothermal performance of the built-in concretes. In the last step, the environmental impacts are assessed. Since the changes in the hygrothermal performance were found to be insignificant (i), the compressive strength were improved by up to 25% (ii) and most of the environmental impact indicators were decreased (iii) at the same time, the findings of the research presented predeterminate such a reuse strategy to wider application and use.

Moisture Transport Associated with Southwest Monsoon Rainfall Over Sri Lanka in Relatively Wet and Dry Rainfall Years

Atmospheric moisture transportation associated with the occurrence of relatively wet and dry southwest monsoon (SWM) years over Sri Lanka is still not fully understood. This study focused on investigating the role of moisture transport in contrast SWM years. We selected seven wet (SWMWet) and nine dry (SWMDry) years for 1985-2015 and found that the whole country experiences above-average (below average) rainfall in SWMWet (SWMDry) years. In SWMWet years, strengthening moisture-laden low-level jets (LLJ) from the Arabian Sea bring a large amount of moisture towards Sri Lanka. In contrast, the weakening of the LLJ from the Arabian Sea direction is observed in SWMDry years. As a consequence, the climatological mean of net moisture flux (4.35 ×105 kg s-1) over the study domain is increased (5.33×105 kg s-1) and decreased (3.98 ×105 kg s-1) in SWMWet and SWMDry years, respectively. With respect to long-term Vertically Integrate Moisture Flux Divergence (VIMFD, –3.28×10-5 kg m-2 s-1), negative anomalous VIMFD (–1.78×10-5 kg m-2 s-1) in SWMWet years and positive anomalous VIMFD (1.44×10-5 kg m-2 s-1) in SWMDry years are recorded, which ascribed above-average and below-average rainfall over the country. Furthermore, strong moisture convergence (divergence) center in the western/ southwestern part of Sri Lanka during the SWMWet (SWMDry) years explain why strong positive and negative SWM rainfall anomalies are concentrated in these two regions. Furthermore, results highlighted a strong relationship between net moisture flux availability and SWM rainfall (r= 0.63) that may explain the observed SWM rainfall variability over the country.