Remote video monitoring for offshore sea farms: Reliability and availability evaluation and image quality assessment via laboratory tests

<div class="page" title="Page 1"><div class="section"><div class="layoutArea"><div class="column"><p class="Abstract">In this article, the availability and reliability of a remote video monitoring system for offshore sea farming plants are studied and tested in laboratory. The scope of the system is to ensure a video surveillance infrastructure so to supervise breeding cages along with the fish inside them, in order to contrast undesired phenomena like fish poaching as well as cages damages. The system is installed on a cage floating structure: it is mainly composed of an IP camera that is controlled by a Raspberry Pi Zero which is the core of the system. Images are streamed thanks to a 3G/4G dongle, while the overall system is powered via two photovoltaic panels charging a backup battery. Simulations are carried out considering two seasonal functioning periods (i.e., winter and summer): each of them is characterised by temperature trends defined according to the average temperatures of the system deployment site, 8 km offshore the city of Piombino, Italy. In order to optimise power consumption without hindering application scenario requirements, the system operates according to a duty cycle of 2 minutes out of 15 (i.e., 8 minutes of operation per hour). The performances of the system are then tested in laboratory exploiting a climatic chamber so to simulate different environmental conditions: variations on image quality are then analysed in order to identify possible dependencies on critical situations related to specific temperature and relative humidity values and to the presence of salt in the air.</p></div></div></div></div>

Trends in surface temperature variability over Mumbai

izs{k.kkRed izek.kksa ls HkweaMy ij lrg rkiekuksa esa m".k izo`fRr dk irk pyrk gSA bl 'kks/k i= esa eqacbZ ds vf/kdre vkSj U;wure rkiekuksa dh izo`fRr;ksa dks Li"V fd;k x;k gSA blesa ,d n’kd ls ysdj izfrnu rd ds fofHkUu dkfyd ekiØeksa ij rkieku izo`fRr;ksa dh tk¡p dh xbZ gSA fo"ke ?kVukvksa ds ?kfVr gksus dh vko`fRr esa izo`fRr;ksa ds fy, ekSle ds leku xq.kksa ds rRoksa dh Hkh tk¡p dh xbZ gSA lkekU;r% eqacbZ esa rkieku dh c<+rh gqbZ izo`fRr ikbZ xbZ gS ftlesa U;wure rkiekuksa dh vis{kk vf/kdre rkieku vf/kd ik;k x;k gS rFkk ;g 95 izfr’kr dh fo’oLrrk Lrj ij lkaf[;dh; :i ls egRoiw.kZ gSA tk¡p dh varj&okf"kZd vkSj varjk ekSle ekuksa nksuksa ij ekWulwu iwoZ vkSj ekWulwu _rqvksa dh vis{kk 'khr _rq vkSj ekWulwuksRrj _rqvksa esa m".krk lfgr ekSleh fHkUurk Li"V :i ls vf/kd ns[kh xbZ gSA pje rkieku ds fo’ys"k.k esa ekSleh fHkUurk Hkh Li"Vr% ns[kh xbZ gSA xeZ fnuksa vkSj xeZ jkrksa esa ?kVukvksa dh vko`fRr 'khr_rq vkSj ekWulwuksRrj _rqvksa dh vis{kk ekWulwu iwoZ vkSj ekWulwu _rqvksa esa vf/kd Li"V :i ls ns[kh xbZ gSA lHkh _rqvksa esa nksuksa LVs’kuksa ij fnu vkSj jkr nksuksa ds le; ds rkiekuksa esa larqfyr m".k izo`fRr ikbZ xbZ gS gk¡ykfd ekWulwuksRrj _rq esa lkarkØqt esa ;g fHkUurk lkaf[;dh; :i ls ux.; ikbZ xbZ gSA Observational evidence points to a warming trend in surface temperatures over the globe. This paper focuses on the trends in Maximum and Minimum temperatures over Mumbai. The temperature trends were investigated at different temporal scales from decadal to daily. The seasonal series were also investigated for trends in frequency of occurrences of extreme events. In general an increasing trend is observed over Mumbai, with the increase in Maximum temperatures more than the Minimum temperatures and statistically significant at 95% confidence level. A seasonal distinction is evident with the warming more in the Winter and Post Monsoon seasons as compared to the Pre Monsoon and Monsoon seasons at both the inter-annual and intra-seasonal scales of investigation. The seasonal distinction was also evident in the extreme temperature analysis. The frequency of occurrences in the hot days and hot nights were more pronounced in the Pre Monsoon and Monsoon seasons as compared to the Winter and Post Monsoon seasons. Symmetric warming trend was observed for both the daytime and nighttime temperatures at both the stations in all the seasons though the variations at Santacruz are statistically insignificant in the Post-Monsoon season

Observed Quantile Features of Summertime Temperature Trends over China: Non-Negligible Role of Temperature Variability

Changes in temperature variability can have more serious social and ecological impacts than changes in the mean state of temperature, especially when they are concurrent with global warming. The present study examines the summertime temperatures’ trends over China from the quantile perspective. Through fully investigating the quantile trends (QTs) of the maximum (Tmax) and minimum temperature (Tmin) using the homogenized observation data and quantile regression analysis, we identify evident region-specific quantile features of summertime temperature trends. In most of northern China, the QTs in Tmax and Tmin for all percentiles generally show strong uniform warmings, which are dominated by a warm shift in mean state temperatures. In contrast, the QTs of Tmax in the Yangtze River Basin show distinguishable inter-quantile features, i.e., an increasing tendency of QTs from cooling trends in the lower percentile to warming trends in the higher percentile. Further investigations show that such robust growing QTs of Tmax across quantiles are dominated by the temperature variance. Our results highlight that more attention should be paid to the region-specific dominance of temperature variability in trends and the related causes.

In-depth temperature and smoke production of charring wood under a constant external heat flux

The combustion characteristics of charring wood have been studied experimentally in a well-ventilated environment of a smoke chamber. A numerical simulation has also been performed for a limited case, with the Fire Dynamics Simulator, to estimate the burning environment. A horizontally placed specimen (ponderosa pine) with a moisture content of 0% or 20% is exposed to a radiant flux (25 kW/m2), with or without flaming ignition. Simultaneous measurements of the specimen’s in-depth temperature and the mass loss determine the charring front (rate) at 300 °C and the gasification rate, respectively. These condensed-phase conditions relate directly to real-time variations of gas-phase quantities: the specific optical density of smoke and the concentrations of toxic gases measured by a Fourier transform infrared gas analyzer. In-depth temperature trends are similar whether the flame exists, whereas the smoke and toxicants’ concentrations are substantially different. After the charring front moves through the specimen, the oxidative pyrolysis continues under the irradiation at high temperatures (up to ∼550 °C). Carbon monoxide and acrolein are produced continuously throughout the test, and the results indicate strong correlations. Although char formation of wood is favorable for fire safety, consequent incomplete combustion produces smoke and toxicants.