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Background/Aim This case report aims to describe an unusual angiographic finding of smoke-stack leakage (SSL) in a vitrectomised eye of a patient with proliferative diabetic retinopathy (PDR). Case description A 59-year-old male with a 17-year history of type 2 diabetes mellitus underwent fundus fluorescein angiography (FA) following vitrectomy for vitreous hemorrhage secondary to PDR. His visual acuity at the time of FA was 6/6 in both eyes. The examination focused on identifying neovascularization elsewhere (NVE) and analysing leakage patterns. FA revealed active NVEs in the left eye with late-phase leakage nasally and inferiorly to the optic disc, while the right eye exhibited a distinctive SSL pattern from residual proliferation. Interestingly, the leakage subsided in the late phase, leaving only staining of the residual fibrous tissue. Conclusion The observed SSL in this vitrectomised eye underscores unique post-surgical dynamics of fluorescein diffusion. This case highlights the importance of recognizing altered leakage patterns in vitrectomised patients, which can impact the evaluation and management of retinal neovascularization in PDR.

— The use of condensing heat exchangers (CHEs) in gas-fired boiler units helps cool the flue gases below the dew point. One of the issues that has to be settled in the case of CHEs installed downstream of boilers is to ensure that the flue gas removal stacks will operate without steam condensation on their inner surfaces. To protect smoke stacks against hydrate corrosion, bypassing of part of combustion products not cooled in the CHE is mainly used in practice. The article presents the results obtained from computations of the heat-transfer processes in the combustion products cooled in a CHE as they move in a reinforced concrete smoke stack fitted with clamped lining, which is protected against hydrate corrosion by bypassing. The computations are carried out for three operation modes of the 180-m high smoke stack, through which flue gases are removed from three power-generating boilers of the BKZ-420-140 NGM type installed at the Samara combined heat and power plant (CHPP), a branch of Samara PAO T Plus. The peculiarity and complexity of the computations are connected with the fact that that the flue gas’s thermophysical parameters and motion velocity in the smoke stack vary during the flue gas cooling process. The parameters’ variation pattern depends essentially on the fraction of gases directed in bypass of the CHE. A mathematical model and computer program are developed for computing the heat-transfer processes in flue gases moving in the smoke stack with CHEs installed downstream of the boilers and with the smoke stack protected against hydrate corrosion by the bypassing method. It has been determined that, for a 180-m high three-layer reinforced concrete smoke stack operating at an outdoor air temperature of –30°С and boilers operating at the nominal load, the fraction of bypassed gases makes 30–35%. With the boilers operating at partial loads equal to 75 and 60% of the nominal value, the fraction of bypassed gases makes 35–40 and 40–45%, respectively. The use of condensing heat exchangers in boiler units results in that the levels of temperature difference, free temperature deformation, and thermal stresses in the smoke stack’s structural elements are reduced by a factor of 1.33–2.80 depending on the fraction of gases passed through the CHEs, thereby enhancing the flue gas removing smoke stack performance reliability.

Smelting is an industrial process involving the extraction of metal from ore. During this process, impurities in ore-including arsenic, lead, and cadmium-may be released from smoke stacks, contaminating air, water, and soil with toxic-heavy metals. The problem of public health harm from smelter emissions received little official attention for much for the twentieth century. Though people living near smelters periodically complained that their health was impaired by both sulfur dioxide and heavy metals, for much of the century there was strong deference to industry claims that smelter operations were a nuisance and not a serious threat to health. It was only when the majority of children living near the El Paso, Texas, smelter were discovered to be lead-exposed in the early 1970s that systematic, independent investigation of exposure to heavy metals in smelting communities began. Following El Paso, an even more serious led poisoning epidemic was discovered around the Bunker Hill smelter in northern Idaho. In Tacoma, Washington, a copper smelter exposed children to arsenic-a carcinogenic threat. Thoroughly grounded in extensive archival research,Tainted Earthtraces the rise of public health concerns about nonferrous smelting in the western United States, focusing on three major facilities: Tacoma, Washington; El Paso, Texas; and Bunker Hill, Idaho. Marianne Sullivan documents the response from community residents, public health scientists, the industry, and the government to pollution from smelters as well as the long road to protecting public health and the environment. Placing the environmental and public health aspects of smelting in historical context, the book connects local incidents to national stories on the regulation of airborne toxic metals. The nonferrous smelting industry has left a toxic legacy in the United States and around the world. Unless these toxic metals are cleaned up, they will persist in the environment and may sicken people-children in particular-for generations to come. The twentieth-century struggle to control smelter pollution shares many similarities with public health battles with such industries as tobacco and asbestos where industry supported science created doubt about harm, and reluctant government regulators did not take decisive action to protect the public's health.

This chapter explains how Big Data is used to gain performance insights into one of America's most successful restaurant chains, Dickey's Barbecue Pit. The firm, which operate 514 restaurants across the US, have developed a proprietary Big Data system called Smoke Stack. Smoke Stack crunches data from POS systems, marketing promotions, loyalty programmes, customer surveys and inventory systems to provide near real‐time feedback on sales and other key performance indicators. The chapter highlights the importance of working with a brilliant partner: one that is willing to work closely with you and that really understands what you're trying to achieve. Another highlight of the chapter is how users right across the company, from the boardroom to the restaurant floor, have access to data that helps them improve performance. Central to this is a flexible, user‐friendly platform.

Pakistan has around 20,000 brick kilns, constituting 3% of global brick production. Consequently, air pollution and air quality indicators have significantly deteriorated. In this study, we examined the effect of different fuel types, such as coal, coal + wheat straw, and coal + rice straw, on stack emissions from FCBTK kilns and Zigzag kilns in Faisalabad, Pakistan. Standard protocols for measuring stack emissions, including smoke opacity, SO 2 , and CO, were used. The results were compared with Pakistan’s Punjab Environmental Quality Standards (PEQS). Specifically, in Zigzag kilns, blended fuels reduced CO emissions to approximately 123.7 mg/Nm 3 with wheat straw and 162.2 mg/Nm 3 with rice straw. In contrast, FCBTKs showed CO emission reductions of 233.17 mg/Nm 3 with wheat straw and 341.07 mg/Nm 3 with rice straw. For SO 2 , Zigzag kilns achieved reductions of 412.7 mg/Nm 3 with wheat straw and 352.4 mg/Nm 3 with rice straw, while FCBTKs reduced emissions by 564.9 and 481.7 mg/Nm 3 , respectively. Smoke opacity in Zigzag kilns improved by 4.6 percentage points with rice straw and 2.3 with wheat straw, whereas in FCBTKs, the improvement was 41.4 and 20.3 percentage points, respectively. Statistical comparisons using Pearson’s correlation and linear regression analysis further indicate that biomass additives combined with coal are more effective as fuels in the brick kiln industry. One‐way ANOVA and Kruskal–Wallis tests, along with post hoc analysis, confirmed significant differences among fuel groups ( p < 0.001), demonstrating strong relationships between fuel composition and emission levels. These additives significantly reduce air pollution and improve community health by lowering emissions of smoke opacity, SO 2 , and CO. According to the results, blending agricultural residues with coal enhances emission performance, with Zigzag kilns showing the most significant reductions.

New techniques have recently been developed and applied to capture reactive nitrogen species, including nitrogen oxides (NOx=NO+NO2), nitrous acid (HONO), nitric acid (HNO3), and particulate nitrate (pNO3-), for accurate measurement of their isotopic composition. Here, we report – for the first time – the isotopic composition of HONO from biomass burning (BB) emissions collected during the Fire Influence on Regional to Global Environments Experiment (FIREX, later evolved into FIREX-AQ) at the Missoula Fire Science Laboratory in the fall of 2016. We used our newly developed annular denuder system (ADS), which was verified to completely capture HONO associated with BB in comparison with four other high-time-resolution concentration measurement techniques, including mist chamber–ion chromatography (MC–IC), open-path Fourier transform infrared spectroscopy (OP-FTIR), cavity-enhanced spectroscopy (CES), and proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF). In 20 “stack” fires (direct emission within ∼5 s of production by the fire) that burned various biomass materials from the western US, δ15N–NOx ranges from −4.3 ‰ to +7.0 ‰, falling near the middle of the range reported in previous work. The first measurements of δ15N–HONO and δ18O–HONO in biomass burning smoke reveal a range of −5.3 ‰ to +5.8 ‰ and +5.2 ‰ to +15.2 ‰, respectively. Both HONO and NOx are sourced from N in the biomass fuel, and δ15N–HONO and δ15N–NOx are strongly correlated (R2=0.89, p<0.001), suggesting HONO is directly formed via subsequent chain reactions of NOx emitted from biomass combustion. Only 5 of 20 pNO3- samples had a sufficient amount for isotopic analysis and showed δ15N and δ18O of pNO3- ranging from −10.6 ‰ to −7.4 ‰ and +11.5 ‰ to +14.8 ‰, respectively. Our δ15N of NOx, HONO, and pNO3- ranges can serve as important biomass burning source signatures, useful for constraining emissions of these species in environmental applications. The δ18O of HONO and NO3- obtained here verify that our method is capable of determining the oxygen isotopic composition in BB plumes. The δ18O values for both of these species reflect laboratory conditions (i.e., a lack of photochemistry) and would be expected to track with the influence of different oxidation pathways in real environments. The methods used in this study will be further applied in future field studies to quantitatively track reactive nitrogen cycling in fresh and aged western US wildfire plumes.

High-rise buildings present substantial challenges for firefighting and rescue operations owing to their considerable height. The stack effect, which becomes more pronounced with increasing building height, accelerates smoke propagation and significantly increases the likelihood of casualties. This study identifies and analyzes the risks associated with fire incidents in high-rise residential buildings. A 49-story building was selected as the reference model, and population density was applied to estimate occupant numbers for the risk assessment. For the damage scenario, one disaster-vulnerable individual per household was assumed. The simulation results revealed that firefighters and vulnerable occupants were exposed to smoke within 541 s. The findings of this study indicate that the stack effect, amplified by building height, exacerbates fire and smoke spread, thereby increasing firefighting risks and potential casualties. These results highlight fire incidents in high-rise structures as a critical category of urban disaster. Furthermore, the study underscores the limitations of existing firefighting facilities in addressing such scenarios and emphasizes the urgent need for new paradigms in firefighting strategies and smoke control technologies to mitigate the risks associated with the stack effect.

To characterize the magnitude of stack effect within stairwells and elevator shafts, differential pressure measurements were taken in fifteen (15) high-rise buildings in four (4) different cities (Cleveland, Baltimore, Minneapolis, and Philadelphia) during the winter months of January–March, 2013. Test buildings ranged in height from 44 m to 150 m (143 ft–492 ft). Outside temperatures during testing ranged from −12°C to 15°C (10°F–59°F). Based on the differential pressures measured, there was evidence of winter stack effect in all buildings tested. On the lower levels of all buildings, air was observed flowing from the building into the stairwells and elevator hoistways with pressure differential magnitudes ranging from −2.7 Pa to −24.9 Pa, −12.0 Pa average (−0.011 in. w.g. to −0.100 in. w.g., −0.048 in. w.g. average). Similarly, in most buildings (excluding Buildings 6 and 7) air was observed flowing from the stair and elevator hoistways into the building on the upper levels with pressure differential magnitudes ranging from 0.5 Pa to 34.9 Pa, 11.2 Pa average (0.002 in. w.g. to 0.140 in. w.g., 0.045 in. w.g. average). Under winter conditions, the data suggests that large quantities of air can migrate, floor-to-floor, via unprotected elevator shafts. Data further suggests activation of the stairwell pressurization system can increase vertical air movement via unprotected elevator shafts. This behavior is expected to impact the movement of smoke floor-to-floor during a fire, as airflow is indicative of smoke migration. The exterior stack force on the building’s envelope (governed by the building’s height and temperature differential between the building interior and exterior) does not always translate proportionally to shaft-to-building differential pressures (i.e., “stack effect”), as each building is unique. Although a building’s height and outside temperature play important roles in determining vertical airflow movement within a building, height alone was not found to be a good predictor of vertical airflow (or smoke movement) within the building due to stack effect. Other variables, such as architectural layout, architectural leakage, wind effects, and ventilation systems should all be considered. Simplified algebraic calculations (i.e. hand calculations) do not treat the building as a complete system, and do not account for all variables involved. Therefore, simplified algebraic calculations may result in inaccurate shaft-to-building differential pressure predictions. Based on this analysis, unless conservative leakage values are used, the simplified algebraic calculations may underpredict the shaft-to-building differential pressures. Using simplified algebraic calculations may be suitable for preliminary approximations, however, for design purposes a more complex analysis is recommended. The more complex analysis should consider other variables that affect pressure differentials such as changes in architectural layout and envelope leakage from floor-to-floor, HVAC systems, and wind.

Atmospheric emissions related to harbor-related activities can significantly contribute to air pollution of coastal urban areas and so, could have implications to the citizens’ health that live in those areas. Of great concern is the local impact of the emissions that are generated while ships are at berth, since not all types of ships switch off the main engines. This paper intends to investigate the influence of the stack configuration for generic cargo ships on the exhaust smoke dispersion, using the Port of Leixões as a case study and a series of wind tunnel experiments with support of Particle Image Velocimetry (PIV) technique. For that, different configurations of the stack of a cargo ship (in terms of height, geometry and diameter) were simulated under the typical wind conditions of the study area. The PIV results indicate negligible differences between the medium and long stack height, with the short stack height presenting a strong impact on the flow field around the stack. For the short stack height, the flow field is not only disturbed by the stack, but also by the cargo ship bridge, with both obstacles promoting disturbances on the flow field and creating a large wake turbulence effect, which is important for the downwash phenomena. Regarding the effects linked with two distinct geometries (straight or curved), the results show that the straight chimney led to higher perturbation of wind field when compared with the curved geometry. The curved stack presents an increase of vorticity, indicating the generation of more turbulent structures. The PIV results also confirmed that higher wind velocity at the inlet conducts to higher vorticity levels, as well as a higher number of Kelvin–Helmholtz structures. For distinct wind conditions the PIV measurements point out different patterns, indicating the northern wind direction as the most favorable condition for the exposure of dock workers to pollutants. Overall, the results showed that a ship stack with a curved end, medium length and smaller diameter has the capability to promote the behaviors in the flow that are coherent with increased pollutant dispersion.

The external wind can change smoke movement patterns inside the staircase and affect smoke exhaust efficiency. This paper analyzes the smoke back-layering phenomenon in the staircase with open stair doors below the fire floor. The effect of the open stair door location and the heat release rate of fires and external wind velocities on smoke movement patterns are investigated numerically. The external wind ranges from 0–5.5 m/s. At 0 m/s, the smoke back-layering phenomenon driven by pressure difference can be found in the staircase with all stair doors closed. With the increasing wind velocity, four smoke behaviors are identified: upward moving smoke, first downward then upward moving smoke, downward moving smoke, and no smoke. Results show that the back-layering distance is mainly influenced by the external wind and heat release rate of fires. Correlations are modified and used to predict the longest back-layering distance with the first downward then upward moving smoke. This helps with arranging the smoke detectors inside a staircase and the fire safety design of high-rise buildings.