Mass Flow Research Articles

Model-Based input energy control for reproducible AISI 316L laser deposited tracks

In the Directed Energy Deposition (DED) process, when the mass flow of metal particles is relatively high, the thickness of the layers increases, leading to a more productive process. The higher the mass flow is, the more difficult it becomes to get a stable melt pool. The accumulation of residual heat in the previously consolidated material constitutes a thermal input affecting the balance at the laser-material interaction zone. An accurate control of the temperature of the laser-material interaction zone is critical to maintain the dynamic viscosity of the liquid metal within the narrow margin in which it can be managed in a stable way. The present work introduces a thermal model in which domains with tunable properties are considered to reproduce the growing of the manufactured sample. Concurrently, a virtual closed-loop PID regulator has been implemented in order to calculate suitable values of laser power to compensate the heat accumulated in the material, offering the results from the model as input process parameters to be directly applied in the real process. The levels of laser power proposed by the model have been experimentally applied, leading to a stable process capable of carrying out in reality the desired component.

Exergoeconomic evaluation and multi-objective optimization of a novel geothermal-driven zero-emission system for cooling, electricity, and hydrogen production: capable of working with low-temperature resources

Geothermal energy is an abundant natural resource in many regions around the world. However, in some areas, the temperature of the geothermal energy resource is too low to be efficiently harvested. Organic Rankine cycles (ORCs) are known for recovering heat from low-temperature resources and generating electricity. Furthermore, half-effect absorption chillers (HEACs) are designed to produce cooling with low-temperature resources. This study proposes a novel configuration that utilizes an ORC for electricity generation, a HEAC for cooling production, and a PEM electrolysis system to produce hydrogen. The power section consists of two turbines, one driven by the vapor produced from the geothermal flow expansion, which powers the PEM section, while the other turbine in the ORC is used to drive pumps and electricity production. First, the system is thermoeconomically analyzed for an initial set of inputs. Then, various parameters are analyzed to determine their influences on system performance. The analyses reveal that the system can work with geothermal source temperatures as low as 80 °C, but the exergy and energy (thermal) efficiencies decrease to around 17% under the base settings. Furthermore, the system is capable of working with resource temperatures up to 170 °C. Ten parameters are found to affect the system’s efficiency and effectiveness. To optimize the system, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is implemented to find the optimum conditions. The objective functions are exergy efficiency and unit polygeneration cost (UPGC), which can conflict. The optimization shows that the exergy efficiency of the system can reach 48% in the optimal conditions (for a heat source temperature of 112 °C and a mass flow rate of geothermal fluid of 44 kg/s), with a hydrogen production rate of 1.1 kg/h.

Floral abundance and corolla length predict the importance of species in connecting urban green areas

Despite the growing urbanization rate and its consequences on biodiversity and species interactions worldwide, the connection among urban green areas, performed by interacting species, is still poorly understood. We evaluated how plant and hummingbird species vary across the urban landscape of a tropical city in Brazil, identifying traits of species taking part in shared interactions between areas. We recorded plant-hummingbird interactions in five green spaces and two remnants of native vegetation, and: (1) contrasted species traits and species-level indices of both plants and hummingbirds; (2) evaluated how species and interactions vary among pairs of areas; (3) used a meta-network approach to identify which pairs of interacting species are more important in connecting areas. Species turnover was the component that better explained the beta-diversity of interactions among sites. In green spaces, plant species presented greater centrality and longer corollas than in remnants. However, both plants and hummingbirds were similarly specialized regardless of the type of area. Trees with large floral displays and with longer corollas shared more interactions and were present in more networks. Most interactions recorded in remnants are unique to them, due to the exclusiveness of some hummingbirds and plant species in such native habitat and are, thus, more sensitive to habitat conversion. Our findings support the importance of preserving remnants and using mass flowering native species in urban afforestation to maintain plant-hummingbird interactions and promote urban biodiversity. We evidenced that few interactions (16.6%) were redundant across areas, indicating a highly susceptible and fragmented system in the urban space.

An Observational View of Structure in Protostellar Systems

The envelopes and disks that surround protostars reflect the initial conditions of star and planet formation and govern the assembly of stellar masses. Characterizing these structures requires observations that span the near-IR to centimeter wavelengths. Consequently, the past two decades have seen progress driven by numerous advances in observational facilities across this spectrum, including the Spitzer Space Telescope, Herschel Space Observatory, the Atacama Large Millimeter/submillimeter Array, and a host of other ground-based interferometers and single-dish radio telescopes. ▪ Nearly all protostars have well-formed circumstellar disks that are likely to be rotationally supported; the ability to detect a disk around a protostar is more a question of spatial resolution rather than whether or not a disk is present. ▪ The disks around protostars have inherently higher millimeter/submillimeter luminosities as compared to disks around more-evolved pre-main-sequence stars, though there may be systematic variations between star-forming regions. ▪ The envelopes around protostars are inherently asymmetric, and streamers emphasize that mass flow through the envelopes to the disks may not be homogeneous. ▪ The current mass distribution of protostars may be impacted by selection bias given that it is skewed toward solar-mass protostars, which is inconsistent with the stellar initial mass function.

Experimental and numerical investigation on the heat and mass transfer performance of tar rich coal in-situ pyrolysis

On ground experiments are conducted firstly to simulate the multi-physics underground pyrolysis of tar rich coal and find out the kinetic parameters of the reaction. And then multi-physics simulation is performed by coupling heat transfer, fluid flow and chemical reactions. Three pyrolysis models are compared and it’s found that the convective flow of heat carrier in coal seam plays an important role in heat transfer although the flow velocity is low. Then the effects of permeability, inlet mass flow rate on heat and mass transfer are investigated for two geometric models with homogeneous and inhomogeneous permeability. It’s found that increasing the permeability is beneficial for fast production of tar. For the homogeneous permeability model, the pyrolysis reaction can be completed in only 140 days when the permeability is 1000 md while for the non-homogeneous permeability model, increasing the inlet mass flow rate can improve the heat and mass transfer performance only in the early stage when the pyrolysis occurs mainly in the fractured zone with higher permeability. The pyrolysis reaction time when the inlet mass flow rate is 0.174 kg/s is 22 days shorter than that of 0.054 kg/s. But in the later stage the inlet mass flow rate has little effect on the reaction rate and brings about a higher pressure drop. The pyrolysis under different well patterns is also compared and the results indicate that four-well heating and six-well heating modes can improve the uniformity and the reaction conversion rate with the same total inlet mass flow rate during the same time. For the six-well heating mode, the pyrolysis reaction can be completed in about 100 days, which is 60 days shorter than the single-well heating mode.

Assessment of the content of biologically active substances in Hypericum perforatum along an altitude gradient

An assessment of the content of flavonoids in the herb St. John’s wort, selected in natural phytocoenosis along an altitudinal gradient, is presented. We used generally accepted methods described in the relevant manuals when conducting research. The material for the study was air-dried samples of the aerial parts of St. John’s wort (Hypericum perforatum) collected at different altitudes. The features of the accumulation of flavonoids (leucoanthocyanins, catechins, flavonols) and the amount of anthracene derivatives in the herb St. John’s wort (Hypericum perforatum) in the phase of mass flowering along an altitudinal gradient were studied. It has been shown that an increased level of anthracene derivatives (in terms of hypericin) is observed at altitudes of 615 - 716 m above sea level. The amount of anthracene derivatives (in terms of hypericin) significantly decreases along the altitudinal gradient. The content of catechins in samples taken along the altitudinal gradient varies within 0.17 - 0.36 mg%. It has been established that plants selected at different altitudes from 615 to 2025 m above sea level are characterized by other content of flavonoids. The samples in the altitude range 615 - 716 m above sea level have the maximum content. The plants selected in the vicinity of the village had the best characteristics for the accumulation of the mass fraction of flavonols. Makhchesk, Irafsky district of the Republic of North Ossetia - Alania, in coenopopulations of a cereal-forb meadow at 1340 m above sea level. Thickets of Hypericum perforatum are found on slopes of southern and southeastern exposure.

Numerical analysis-based performance assessment of the small-scale organic Rankine cycle turbine design for residential applications

The organic Rankine cycle (ORC) is one of the most common ways to use energy resources to utilise waste heat. Integrating ORC with other systems, such as cooling or heating applications, is also helpful for residential uses. In the ORC system, the turbines are the most critical component determining the system's efficiency. This study conducted a computational fluid dynamics study on a regenerative flow turbine that can be used in small-scale organic Rankine cycle systems. For the higher temperature applications, the analyses were performed using n-pentane working fluid for 1500 and 3000 rpm turbine speeds, inlet temperature between 475–550 K, outlet pressure between 0.9–1.2 MPa, and mass flow rates between 0.5–1.0 kg/s. As a result of the analysis, the isentropic efficiency varies between 4.97 % and 12.52 %. It was concluded that the output power obtained from the turbine varies between 0.53 kW and 2.96 kW. The analyses were also performed for lower temperature (363 and 393 K), pressure (0.05 MPa and 0.3 MPa) and mass flows (0.1 to 0.25 kg/s) applications. In this case, the isentropic efficiency of the turbine varies between 6.23 % and 14.52 %, whereas the power generation varies between 0.068 and 0.521 kW.

Development and validation of an innovative headspace collection technique: volatile organic compound patterns emitted by different developmental stages of Halyomorpha halys

Over the past two decades, several headspace collection techniques have been used to detect and identify volatile organic compounds (VOCs) emitted by plants, pests, air, and soil. Volatiles emitted by pests and infected plants are usually found at low concentrations. The important challenge is to be able to capture an exact collection of relative quantities of the relevant VOCs. Here we present an innovative headspace collecting device (HSCD) for sampling VOCs, which ensures an exact regulation of mass flow velocity and collected total gas volume allowing besides qualitative analysis of collected VOCs, an exact comparison of their relative quantities in plant or insect headspace samples. The HSCD possess six parallel odor collection systems each consisting of a digital mass flow detector and controller connected to a vacuum pump, which are mounted in a trolley suitcase, connected by tubes, and wired electrically. The programming of the channels, can be done by a digital control unit. Using the HSCD, VOCs emitted by the brown marmorated stink bug (BMSB), Halyomorpha halys, from its different developmental stages including egg, nymphal stages, nymphal exuvia, and adults were collected on thermal desorption tubes and analyzed using an automated thermal desorber connected to a gas chromatography-mass spectrometry system. Forty-five VOCs were identified in total, which mainly consisted of tridecane (4.36-69.33%), E-2-decenal (4.24-26.48%), 2-undecenal (0.63-50.03%), and E-4-oxo-2-hexenal (1.22-20.58%). The random forest analysis revealed three different chemical patterns among BMSB life stages samples. In conclusion, these results indicate that the new developed HSCD, a mobile, easy to use, and reliable instrument, has a high potential to sample relevant VOCs of a specific life stage of an insect both qualitatively and quantitatively. It was demonstrated that this information can be used for identifying specific chemical signatures, which fit to specific life stages of the BMSB, and may be used as biomarker for on-site detection of this pest e.g. in shipping containers or agricultural areas.

Features of using Tropicana 1 on potatoes in the forest steppe of Western Siberia

The results of experimental studies on the effectiveness of using the medicine Tropikanka 1 during the growing season of potatoes of the Vega (early) variety are presented. Arid conditions were observed during the experiments, especially in May and June. Tropikanka 1 was used during the potato growing season by spraying plants at the beginning of budding and mass flowering in concentrations of 0.005, 0.01, and 0.02% with a working fluid flow rate of 300 l/ha. Spraying with water was used as a control. The research aims to develop ways to use environmentally friendly organic fertilizer to stimulate the growth and development of potatoes and increase their yield with good quality and product safety. It was shown that on gray forest heavy loamy soil of the forest-steppe of the Ob region under conditions of acute moisture deficiency in May, June, and early July 2023, the use of Tropikanka 1 during the potato growing season accelerated the rate of progression of the phenological phases of potatoes by two days compared to the control (water). The maximum leaf area was formed during the use of the drug Tropikanka 1, especially at a concentration of 0.01% - 1.4 times higher than the control. Against the background of spraying potato plants during the growing season with Tropikanka 1, the yield of tubers increased by 1.3 times. The total yield in the variants with spraying plants with Tropikanka 1 at a concentration of 0.01%for the early variety Vega was 27.1 t/ha, 21% higher than the control. An increase in marketable yield of up to 30% was noted when using liquid fertilizer based on dilution of poultry manure treated with nitric acid. An increase in the quality of potato tubers was established with an increase in dry matter content by 0.3%, starch by 0.4%, and vitamin C by 0.6% mg/kg. The concentration of nitrates was below the MPC. It was noted that using liquid fertilizer Tropikanka 1 did not reduce the safety indicators of the early potato variety Vega tubers during long-term storage.

Sweeping JET actuator for the control of flow separation on a hump airfoil

Flow control can effectively improve lift and delay flow separation. Sweeping jet (SWJ) actuators have attracted increasing interest for as active flow control actuators. In this paper, the characteristics of the SWJ actuator were studied through large-eddy simulation and experiments. It was discovered that the oscillation frequency of the SWJ actuator is directly proportional to the mass flow rate, and its working principle was determined. Subsequently, SWJ actuators with [Formula: see text], 1.9%, and 6.6% were applied to flow control on the hump airfoil. It was observed that with an increase in momentum coefficient, the SWJ actuator was able to push the shear layer toward the hump airfoil surface, leading to a reduction in the size of the separation vortex. At [Formula: see text], it was achieved that the reattachment point of the separation vortex shifted upstream from [Formula: see text] to [Formula: see text], and the separation vortex size essentially disappeared. During the investigation of the flow control mechanism of the SWJ actuator, it was found that the SWJ actuator periodically generates a separation vortex V1, which has entrainment effects, resulting in the formation of an external jet on the airfoil surface, effectively inhibiting flow separation.

Performance investigation of a low-power Hall thruster fed on iodine propellant

The common propellants used for electric thrusters, such as xenon and krypton, are rare, expensive, and difficult to acquire. Solid iodine attracts much attention with the advantages of low cost, extensive availability, low vapor pressure, and ionization potential. The performance of a low-power iodine-fed Hall thruster matched with a xenon-fed cathode is investigated across a broad range of operation conditions. Regulation of the iodine vapor’s mass flow rates is stably achieved by using a temperature control method of the iodine reservoir. The thrust measurements are finished utilizing a thrust target during the tests. Results show that thrust and anode-specific impulse increase approximately linearly with the increasing iodine mass flow rate. At the nominal power of 200 W class, iodine mass flow rates are 0.62 and 0.93 mg/s, thrusts are 7.19 and 7.58 mN, anode specific impulses are 1184 and 826 s, anode efficiencies are 20.8% and 14.5%, and thrust to power ratios are 35.9 and 37.9 mN/kW under the conditions of 250 V, 0.8 A and 200 V, 1.0 A, respectively. The operating characteristics of iodine-fed Hall thruster are analyzed in different states. Further work on the measurements of plasma characteristics and experimental optimization will be carried out.

Transonic Compressor Darmstadt Open Test Case: Experimental Investigation of Stator Secondary Flows and Hub Leakage

Abstract The future trend of clean sky aviation has led to a smaller core engine, resulting in highly loaded stages with increased relative tip gaps and leakage flows, which causes a reinforced influence of secondary flow phenomena. This article experimentally investigates the secondary flow effects in the 3D-optimized shrouded stator of the TUDa-GLR-OpenStage, representative of a transonic high-pressure compressor front stage, and its susceptibility to typical hub leakage flows. The impact of stator hub leakage on efficiency and total pressure ratio is investigated for several operating speeds, from subsonic to nominal transonic operating conditions. Steady five-hole probe and time-resolved virtual multi-hole probe measurements at different operating conditions at nominal speed are conducted to investigate the underlying loss mechanisms. The leakage mass flow is determined using the measured pressure difference within the fin seal. Steady results show that the optimized 3D stator effectively suppresses the hub corner separation compared to the predecessor 2D stator, but its performance is further limited by a near-tip separation. With the increased stator hub leakage (at a leakage-to-main flow ratio of about 0.4%), the compressor isentropic efficiency generally drops (by about −0.5%) at the full operating range due to an enhanced hub corner separation effect. However, the increased leakage also helps alleviate the tip-corner separation when operating near stall, leading to a smaller efficiency penalty under these conditions. Unsteady results reveal the sensitivity of transient compressor performance to the passing rotor wake, but limited interaction between this phenomenon and the increased leakage is observed. These findings provide insight into the stator hub leakage-related penalties on the compressor aerodynamics efficiency.

Effect of wood flour and compatibilizer content on the properties of wood-plastic composites

Wood-plastic composites (WPC) with are prepared by melting and mixing wood flour (WF) and thermoplastics which has green and biodegradable advantages and is of great significance in the development of the era of global resource scarcity. In this work, recycled polypropylene and WF were used as raw materials and commercially available maleic anhydride grafted polypropylene (MAH-g-PP) was used as a compatibilizer. The extrusion injection molding method was used and investigated by varying the amount of WF and compatibilizer added. The composites were analyzed for micro-morphology, melt mass flow rate, mechanical properties, and thermal stability by scanning electron microscopy (SEM), melt flow rate tester (MFR), electronic universal testing machine, and thermogravimetric analysis (TGA). According to the results, WF shows a positive effect in terms of storage and loss modulus of the composites, but it shows a negative effect in terms of thermal stability and mechanical properties. As an effective compatibilizer, MAH-g-PP plays an important role in improving the mechanical properties of the composites, especially at an additional level of 4 wt%, which maximized the overall performance of the composites.

Numerical simulation and experimental study on ultrafine powder spiral transportation degassing

Aiming at the problems of ultrafine powders of high air content and environmental pollution, low measurement accuracy and low efficiency in packaging and filling process, the research on degassing spiral powder transportation was carried out. Discrete element method and physical experiment method were used to simulate and test the mass flow rate, material density and dust concentration of packaging environment of equidistant spiral and degassing (variable pitch) spiral powder transportation, and the transportation effects of equidistant spiral and degassing spiral were analyzed.Simulation and test results show that the average mass flow rate of the degassing screw is 0.639 kg s−1 with the same screw outer diameter, inner shaft diameter, length and rotational speed, and the flow rate fluctuates with the percentage of fluctuation in the range of 7.19% − 10.02%. The degassing spiral increases the mass flow rate of the feeding device and reduces the flow fluctuation,and the maximum densification of the material was increased by about 7.25%. With the increase of rotational speed, the environmental dust lifting degree of both spiral filling processes increased, but under the same rotational speed, the dust lifting degree of the outlet of the degassing spiral was significantly reduced compared to the isometric spiral, and the rotational speed was increased from 80 to 120 r min−1, the maximum dust lifting degree of the isometric spiral was 37.88%, and the average dust lifting degree of the maximum was 25.59%, and the maximum dust lifting degree of the degassing spiral was 21.59%. The maximum dust lifting degree of the degassing spiral is 21.18%, and the maximum increase of the average dust lifting degree is 14.49%. Degassing spiral device effectively realises efficient and clean packaging of ultra-fine powder.

Heat flow topology-driven thermo-mass decoupling strategy: Cross-scale regularization modeling and optimization analysis

The liquid desiccant dehumidification (LDD) is both eco-friendly and highly effective in humidity control, widely investigated across diverse angles. This study expands the application of the newly devised heat current method to examine the liquid desiccant dehumidification process. It introduces a new regularized temperature, which includes using a heat flow topology driven thermo-mass decoupling strategy, and constructing the heat current model by defining both the thermal resistance and moisture resistance. It significantly extends the application of the heat current method, clarifying the thermo-mass coupling energy transfer mechanism. The findings indicate that key factors influencing system performance indicators include total thermal conductivity (αA), solution mass flow rate (ms), air-solution mass flow rate ratio (RA/S,D), and heat source temperature (tH). Furthermore, under the influence of distinct thermal conductivities, the optimal output values for performance indicators, including moisture removal rate, exergy efficiency and entransy efficiency, are determined as 8.4 g/s, 71.2%, and 12.3%, respectively. The results of synergistic influence analysis reveal that, for the performance indicator entransy efficiency, msand RA/S,D display a significant degree of synergistic influence, resulting in a strong positive effect and benefiting 68.53% of the total area. Multi-objective optimization indicates a trade-off relationship among the system performance evaluation indicators moisture removal rate, exergy efficiency and entransy efficiency, with optimal solution values of 3.25 g/s, 65.92%, and 12.01%, respectively.

Compact heat pipe heat exchanger for waste heat recovery within a low-temperature range

Heat pipe heat exchangers (HPHX) are attracting attention for being capable of effective heat exchange through phase change. Much waste heat is generated at low-temperature sources, but there has been a lack of research on this. Most previous studies focus on large HPHXs over 1 m in length. In the present study, a compact HPHX (185 × 70 × 140 mm3) with nine heat pipes was fabricated, and the potential for waste heat recovery (WHR) was investigated at low heat sources. Also, the thermal performance of the HPHX was compared with and without the fin of the heat pipe. Experiments were conducted by changing the hot-side gas temperatures (50, 75, 100, and 125 °C) and mass flow rates (0.03, 0.04, and 0.05 kg/s). The heat transfer rate and pressure loss had a linear relationship with the hot-side temperature and mass flow rate. Despite a low temperature 50 °C, more than 100 W of heat can be recovered using a compact HPHX. At least 1.8 times improved thermal performance was obtained in HPHX in which finned heat pipes were installed. These results are expected to serve as indicators for various applications that generate low-temperature waste heat, such as clothes dryers and kitchen hoods.

Numerical Investigation of PV/T System by Using Graphene Based Nanofluids

The effective use of solar radiation can be maximized by the implementation of a novel hybrid device referred to as a photovoltaic thermal collector (PV/T), which has the capability to simultaneously generate both electrical and thermal energy. As temperature increases, the efficiency of the photovoltaic (PV) cell drops. The present work employs graphene nanofluids as a means to decrease the temperature of the system in order to evaluate the photovoltaic thermal (PV/T) performance. The PV/T system is subjected to Computational Fluid Dynamics (CFD) simulation, wherein graphene nanofluids of different volume concentrations (0%, 0.1%, 0.2%, and 0.3%) and mass flow rates (0.065, 0.075, and 0.085 kg/s) are employed. The PV/T system demonstrated enhanced performance as a result of the implementation of the proposed approach, which effectively reduced the temperature of the solar cell during the period of maximum solar radiation, spanning from 9 AM to 4 PM. The utilization of the system was employed for the generation of thermal and electrical energy due to its respective thermal and electrical efficiency of 67% and 11.5%. The completed research has demonstrated that the integration of graphene nanofluids has the potential to enhance the efficiency of PV/T systems.

Transport and deposition of the 39.8 ka Campanian Ignimbrite large-scale pyroclastic density currents (Italy)

Processes of transport and deposition of large-scale pyroclastic density currents, which transport 102−103 km3 of material, are still poorly understood. The volcanic explosivity index (VEI) 7 Campanian Ignimbrite pyroclastic density current is one such poorly understood case that is subject to lively scientific debates about its origin and processes. The Campanian Ignimbrite is related to the 39.8 ka eruption that formed the partly submarine and active Campi Flegrei caldera in Italy. The related pyroclastic density current extended over an area of more than 6000 km2 on land around the caldera, with a final runout of ∼75 km, and surmounted mountain ridges higher than 1000 m above sea level, even at distal reaches. We used physical characteristics of the ignimbrite to understand the transport and emplacement dynamics of the Campanian Ignimbrite pyroclastic density current. Thickness, mass, and clast-size distributions across paleotopography were used to infer that the main transport system was a dilute, density-stratified pyroclastic density current, which was at least 1.5 km thick, which was short-lived (possibly as short as ∼20 min), and which had a mass flow rate of ∼1011 kg/s. At its base, high-concentration undercurrents formed and interacted with the rough paleotopography, laying down a low-aspect-ratio ignimbrite sheet when on flat plains, but generating back-flows from ridges and channeling in paleovalleys. The deposit is predominantly a massive valley-pond ignimbrite facies, even across rough mountain terrains. The absence of veneer facies on steep slopes reflects the near-Newtonian rheology of the undercurrents, interpreted as fluidized dense granular flows. This work advances the interpretations of pyroclastic density current deposits, which do not necessarily directly reflect conditions in the transport system.

Predicting compressor mass flow rate using various machine learning approaches

Abstract A major focus of the present study is to construct high-fidelity models for predicting corrected mass flow rates based on the collected compressor map data. Both traditional machine learning research and modern deep learning techniques have been employed to obtain well-fitted regression models of compressor mass flow rate. As traditional machine learning methods, Multiple Linear Regression and Random Forest, are conducted on compressor maps for prediction of corrected mass flow rate. The time series-based deep learning models are able to capture the overall trend of a given input for specific map data. Therefore, a time series-based deep learning technique, namely Gated Recurrent Unit has been employed to improve regression results. Besides, the prediction capabilities of the models, results also show that the proposed models can be used for the development of dynamic aero-thermal mathematical models of gas turbine engines and mass flow rate models created for dynamic compressors in other disciplines.

Atmospheric gaseous mercury and associated health risk assessment in the economic capital of India.

Mercury cycling in coastal metropolitan areas on the west coast of India becomes complex due to the combined effects of both intensive domestic anthropogenic emissions and marine air masses. The present study is based on yearlong data of continuous measurements of gaseous elemental mercury (GEM) concentration concurrent with meteorological parameters and some air pollutants at a coastal urban site in Mumbai, on the west coast of India, for the first time. The concentration of GEM was found in a range between 2.2 and 12.3ng/m3, with a mean of 3.1 ± 1.1ng/m3, which was significantly higher than the continental background values in the Northern Hemisphere (~ 1.5ng/m3). Unlike particulates, GEM starts increasing post-winter to peak during the monsoon and decrease towards winter. July had the highest concentration of GEM followed by October, and a minimum in January. GEM exhibited a distinct diurnal cycle, mainly with a broad peak in the early morning, a narrow one by nightfall, and a minimum in the afternoon. The peaks and their timing suggest the origin of urban mobility and the start of local activities. A positive correlation between SO2, PM2.5, temperature, relative humidity, and GEM indicates that emissions from local industrial plants in the Mumbai coastal area. Principal component analysis (PCA) and cluster analysis (CA) confirm this fact. Monthly back trajectory analysis showed that air mass flows are predominantly from the Arabian Sea and local human activities. Assessment of human health risks by USEPA model reveals that the hazardous quotient, HQ < 1, implies negligible carcinogenic risk. GEM observations in Mumbai during the study period are below the World Health Organization's (WHO) safe limit (200ng/m3) for long-term inhalation.