Moisture Condensation Research Articles

Enhancing Preservation: Addressing Humidity Challenges in Indonesian Heritage Buildings Through Advanced Detection Methods Point Cloud Data

Heritage buildings are valuable assets that represent national cultural identity. Proper building maintenance is a major issue for preservation, as building monitoring aspects and preventive measures are often only taken after physical damage happens. In the context of Indonesian heritage buildings, high levels of humidity which may cause condensation and soil dampness are often overlooked. Early detection methods are urgently required to effectively detect potential risks of condensation. This study aims to investigate condensation risk for heritage building surfaces by calculating thermal properties (i.e., emissivity, albedo) and Blinn-Phong BRDF values through the integration of thermal imaging and 3D scanning techniques. This approach supports architects and conservators in making informed decisions to protect and maintain cultural heritage structures. The study also highlights gaps in current Indonesian regulations regarding moisture presence and condensation risk detection in heritage buildings.

Triple oxygen isotope variability of precipitation in a tropical mountainous region

We present one year of δD, δ18O, d-excess, and Δʹ17O data from monthly precipitation at a Caribbean coastal site in Panama and from tap waters across the country to constrain geographic, climate, and moisture source controls on isotopic variability and better understand the sources and mechanisms of precipitation in Central America, a region facing significant modifications to the annual rainfall cycle due to climate change. Monthly precipitation δD ranged from –52.2 to +14.3 ‰, δ18O from –7.6 to +0.4 ‰, d-excess from +7.1 to +11.6 ‰, and Δ′17O from +11 to +29 per meg. Rainy season precipitation samples were found to have lower δD, δ18O, and d-excess due to Rayleigh distillation during the condensation and rainout of Pacific moisture over the central cordilleras, which results in decoupling between d-excess and Δ′17O. Outlier Δ′17O values during peak dry and rainy months may reflect seasonal changes in water vapor sourcing, from Caribbean to Pacific and/or locally recycled moisture, or may be a result of organic contamination. Tap water δD ranged from –82.3 to –14.3 ‰, δ18O from –11.6 to –2.4 ‰, d-excess from +4.3 to +12.2 ‰ and Δ′17O from –2 to +84 per meg. Tap water δD and δ18O values increase eastward due to lower orographic effects and Pacific and locally recycled moisture contributions to rainfall and greater secondary evaporation. Tap water d-excess and Δ′17O values are also de-coupled but lack clear spatial trends and controls. The results of this study indicate the promise of adding Δ′17O to the isotopic toolkit in tropical mountainous regions with complicated water cycling dynamics and provide a baseline for future triple oxygen isotope investigations.

Net Zero Agrivoltaic Arrays for Agrotunnel Vertical Growing Systems: Energy Analysis and System Sizing

Local indoor farming plays a significant role in the sustainable food production sector. The operation and energy costs, however, have led to bankruptcy and difficulties in cost management of indoor farming operations. To control the volatility and reduce the electricity costs for indoor farming, the agrivoltaics agrotunnel introduced here uses: (1) high insulation for a building dedicated to vertical growing, (2) high-efficiency light emitting diode (LED) lighting, (3) heat pumps (HPs), and (4) solar photovoltaics (PVs) to provide known electric costs for 25 years. In order to size the PV array, this study develops a thermal model for agrotunnel load calculations and validates it using the Hourly Analysis Program and measured data so the effect of plant evapotranspiration can be included. HPs are sized and plug loads (i.e., water pump energy needed to provide for the hybrid aeroponics/hydroponics system, DC power running the LEDs hung on grow walls, and dehumidifier assisting in moisture condensation in summer) are measured/modeled. Ultimately, all models are combined to establish an annual load profile for an agrotunnel that is then used to model the necessary PV to power the system throughout the year. The results find that agrivoltaics to power an agrotunnel range from 40 to 50 kW and make up an area from 3.2 to 10.48 m2/m2 of an agrotunnel footprint. Net zero agrotunnels are technically viable although future work is needed to deeply explore the economics of localized vertical food growing systems.

Analysis of the sintering process of the sintering charge in a high layer. Report 2. Reduction and oxidation processes, moisture behavior and gas dynamics of the sintering process

Piece of information 1 of this article briefly examines the history of the development of modeling the sintering process. To study it, a modern three-dimensional mathematical model was used. Its adaptation was made for the operating conditions of sinter plant No. 5 of PJSC “MMK”, on whose sinter machines the mix is sintered in a bed 700 mm high. Studies have been carried out on the formation and development of fuel combustion and limestone dissociation zones. In the information under consideration, the reduction and oxidation processes of moving the temperature fields of the material with the melt, the combustion zone, processes of gas formation along the height of the bed are presented together. It has been established that a small-height Fe2O3 reduction zone is formed under the fuel combustion zone, and that the conditions for the formation of an oxidation zone under the fuel combustion zone, discussed in the literature, are extremely unfavorable. An analysis of the processes of drying and waterlogging of the mix in a high bed was carried out. A lesser negative impact of moisture condensation in a high bed has been established compared to a low or medium height bed. The gas-dynamic operation of the bed under the ignition hearth with throttling conditions of the first vacuum chambers of the sinter machine is considered. A decrease in the rate of gas filtration at the outlet of the bed was established in comparison with the input rate after the drying and fuel combustion zones exited the bed.

Capillary Condensation Mediated Fluidic Straining for Enhanced Bacterial Inactivation

AbstractBiomaterials capable of continuously inactivating pathogens are essential for suppressing transmission of infectious diseases, such as epidemic cerebrospinal meningitis and pulmonary tuberculosis. Here, capillary condensation of air moisture within nano‐confined spaces between superhydrophilic rigid nanorods is shown and target microbiology spontaneously stretch and inactivate aerosolized microorganisms. Specifically, the negative Gaussian curvature‐shaped water condensate causes fluidic straining, comprising surface tension and Laplace pressure, strong enough to deform and eliminate the selected bacteria. Plate counting quantifies the sharply reduced contact‐killing period for superhydrophilic and bare nanorods (6 vs 100 min for E. coli, 20 vs 120 min for S. aureus) under relative humidity of 70%. Theoretical calculations and experimental studies indicate increased mechanical straining and mechano‐bactericidal by improving air moisture content. To further illustrate utility, long‐term antibacterial medical masks are fabricated by integrating such nanorods onto commercial fabrics. Collectively, these findings highlight the immense potential of capillary condensation‐induced fluidic straining as an eco‐friendly, broad‐spectrum, and highly efficient antibacterial strategy.

Future projection of tropical cyclone genesis in the Western North pacific using high-resolution GCMs and genesis potential indices

The study employed high-resolution atmospheric general circulation models (AGCM) to simulate tropical cyclones (TCs) and evaluated two TC genesis potential indices in reflecting projected TC changes in the western North Pacific (WNP) under a warming scenario. Both indices accurately represented the seasonal variation of TC genesis frequency (TCGF) and its spatial distribution in historical simulations and observation data. The widely-used TC genesis potential index (χGPI) projected a significant increase in TCGF in response to a warmer ocean surface. However, this projection conflicted with the significant reduction in the model projection due to the dominant control of SST on the χGPI. Higher SST in remote ocean basins often over dominated the destabilization effect of in-situ warmer SST and caused more stable atmospheric conditions in the WNP, resulting in fewer TC occurrences. By contrast, the revised index (χMqGPI), which considers gross moisture condensation, projected a TCGF decrease that more accurately reflected the decreasing trend of TCGF in the warming simulations by AGCM, although the degree of reduction was smaller than that derived directly from TC detection scheme. The results suggest the plausibility of using χMqGPI, based on the results of multimodel coarse-resolution CMIP6 climate models, to project future changes in TCGF in the WNP.

Development and verification of a graphical detection system for multi-field interactions in stored grain based on LF-NMR

Stored grain is a complex ecosystem in which intricate multi-field interactions exist among abiotic and biotic factors, as well as the surrounding environment. Clearly understanding these interactions is crucial for ensuring grain storage security. This study developed a graphical detection system based on low-field nuclear magnetic resonance (LF-NMR) technology, which consists of an LF-NMR imaging analyzer, a small grain container, and dedicated software. This system can simultaneously detect the temperature, moisture, and humidity of a grain sample stored in the grain container and visually present the cloud maps of these fields through the dedicated software. To verify the system's performance, two laboratory storage experiments with paddy rice samples were conducted for 15 d. The results indicated that the measured cloud maps could accurately depict the variations in the temperature, moisture, and humidity fields within the stored paddy rice samples during the storage period. The areas with potential risks of fungal growth, grain sprouting, and moisture condensation due to the multi-field interactions could also be identified through the cloud maps, which demonstrated the credible performance of the system. This system could provide a new technical means to uncover the complex coupling relationships within grain storage ecosystems.

Effect of insolation heating of roof coverings on their performance reliability

Introduction. The article addresses the issues of ensuring the performance reliability of warm roofs in terms of condensation moisture accumulating in their structures, which causes leaks on the upper floors of buildings. Such problems are often revealed when buildings are inspected during repair and reconstruction works. Leaks in the ceilings of buildings with warm roofs were detected in dry, sunny weather with significant heating of the roof covering due to solar radiation.Aim. To examine the effect of the insolation heating of a roof covering on the formation of condensate in the warm roof of a building in summer, taking into account its design solution.Materials and methods. Materials are presented on inspection of buildings in the Moscow region for repair and reconstruction needs; they reveal the problem of leak formation in the warm roofs of buildings on dry, sunny summer days. The process of moisture transfer through the exterior covering was analyzed through analytical calculations using the roof design solution in the considered structure as an example.Results. The calculation of moisture transfer yielded vapor transmission resistance, conventional true and maximum partial pressures of water vapor, as well as temperatures at the layer boundaries in the studied structures. Changes in these parameters across the thickness of structures were revealed via a graphical method, which showed where the dew point indicating possible condensation in the covering is formed. For a comparative analysis, moisture transfer was calculated for a similar design in which mineral wool insulation was replaced by extruded polystyrene.Conclusions. 1. The calculations of moisture transfer in the examined covering designs confirmed the formation of condensate due to the insolation heating of the roof in summer. 2. The choice of a covering design solution in the design of buildings should be based on accurate heat and moisture calculations taking into account climatic conditions in the construction area, including for the summer season.

Evaluation of three suction pretreatment systems for the air compressor

Air compressor, as the power source of pneumatic tools, suffers the problems of low efficiency and high failure rate in summer. In this paper, three suction air pretreatment systems are presented, which are characterized by the cold sources: a vapor compression refrigeration unit, a water chilling unit and a combination of water chilling unit with cooling tower. Models for the thermodynamic and economic performance evaluation of the three systems are established and solved. The moisture diffusion coefficient is applied to consider the influence of the moisture condensation and the Marshall and Swift coefficients is introduced to consider the capital change over time. Formula to calculate the efficiency of refrigeration compressor is adopted. Besides, the system total efficiency, percentage of power saving (PPS) and payback period (PBP) are defined as performance indexes. A comparative study with typical meteorological data of hot-dry regions and hot-humid regions is conducted to analyze the superiority of each system under the operation conditions of varied suction air temperature and volume flow. According to the results, optimal spray water flowrate exists for each operation condition and an air–water ratio of 0.8 is recommended. When the suction air temperature decreases, the PBP of each system increases and a sharp increase occurs when the temperature is lower than the air dew point temperature. A suction air temperature of 26 ℃ is suggested. Direct air cooling with an evaporator is preferred when the suction air volume flowrate is smaller than 60 m3/min for hot-humidity regions. The combined system is significantly superior in hot-dry regions. The PBP of the three systems is all longer than 10 months. How to guarantee the usage rate is the key for enterprises to consider the use of suction air pretreatment systems.

Experimental Construction and Validation of Revised Drucker–Prager Model Using Finite Element Method for Moisture Condensation Zone in Bentonite-Bonded Silica Sand

For predicting casting deformation by FEM (finite element method) thermal stress analysis, this paper experimentally constructed and validated the Drucker–Prager (DP) model and its revised model (RDP) for the condensation zone of bentonite-bonded sand molds. The condensation zone has been known as a remarkably low-strength region in the mold, and its mechanical response should be dominant to the casting deformation. To construct the models through uniaxial and triaxial compression tests, the test pieces reproducing the condensation zone were prepared by permeating water vapor through a test piece of bentonite-bonded sand. The constructed models were then applied to the FEM stress analysis of the triaxial test to validate them by comparing the analytical stress–strain curves with the experiment. The experimental stress–strain curve after permeating water did not show any distinct yielding point; however, the analytical curve with the original DP model clearly exhibited a yielding point due to the yield criterion of the model. The distinct yielding criterion should be essentially fatal to reproduce the stress–strain relationship of the condensation zone. Contrarily, the RDP model reproduced the experimental curve with less than 10 % error and was found to be advantageous for modeling the smooth stress–strain relationship of the condensation zone.

Corrosion Behavior of Zn-Al-Mg-Si Coatings in Sulfur Dioxide-Containing Environment

Zn-Al-Mg-Si coatings are an excellent alternative to conventional hot-dip galvanizing coatings. Their high corrosion resistance in corrosive environments containing chlorides and CO2 is well recognized. But sulfur dioxide is also an important stimulator of corrosion in the atmospheric environment. This article presents the results of microstructure (SEM/EDS/XRD) and corrosion behavior tests of Zn-Al-Mg-Si coatings obtained by a double hot-dip method on HSLA steel. The corrosion resistance of the coatings was determined in the sulfur dioxide test with general condensation of moisture (EN ISO 6988). In the corrosion test, Zn-Al-Mg-Si coatings showed twofold smaller weight loss compared to conventional hot-dip zinc coatings. It was found that the corrosion behavior of coatings was influenced by the structural components revealed in the outer layer: Al-rich dendritic and interdendritic areas with Zn/MgZn2 eutectic, MgZn2 intermetallic and Si precipitates and their electrochemical nature. The increase in corrosion resistance was caused by the formation of beneficial corrosion products: layered double hydroxides (LDHs) based on divalent Mg2+ and Zn2+ cations, trivalent Al3+ cations and SO42− anions, and zinc hydroxysulfate—Zn4SO4(OH)6∙5H2O. The presence of Si precipitates could cause pitting corrosion of coatings.

Convective heat transfer with condensation in crossflow of a circular cylinder: Experiments and simulations

Forced convection heat transfer has been widely studied but not with the inclusion of condensation phenomenon particularly in crossflow of a cylinder. In this study, the convective heat transfer with moisture condensation of the air that is relevant for food thawing applications with the airflow around a circular cylinder was investigated. Experiments were carried out that represents food air-thawing conditions such as the Re number within a subcritical range, and the relative humidity of air being varied. Heat flux was measured at different angles around the cylinder to characterize the local heat transfer. A three-dimensional CFD modeling was subsequently carried out with the appropriate choice of turbulence model, and the condensation with the presence of non-condensable gasses. The simulation results were well correlated with the experimental data. The heat transfer rate on the leeward side is enhanced with the development of the detached vortex at higher Re number; hence, changing it within a certain range is an effective method to improve the uniformity of convective condensation heat transfer. An increase in the relative humidity was found to enhance the average convective condensation heat transfer. An empirical correlation that predicts the overall heat transfer was developed adopting Nu, Re, and Pr numbers.

Identification of corrosion factors in blast furnace gas pipe network with corrosion big data online monitoring technology

To mitigate the accelerated corrosion of blast furnace gas pipelines induced by severe environmental conditions, this study has established an extensive high-throughput sensor system in the field. It leverages corrosion big data technology to investigate the corrosion factors affecting industrial gas pipelines and to precisely analyze the influence of related variables. The results indicated that temperature reduction is the driving factor that causes increased pipeline corrosion. On one hand, temperature fluctuations impact the evaporation and condensation of moisture in the tube. On the other hand, temperature fluctuations, in conjunction with corrosive gases, exhibit significant coupling effects, resulting in more severe corrosion. In addition, critical points for relative humidity and temperature are evident. When humidity exceeds 50%, corrosion in the pipe begins to increase, reaching its peak at 70%. The increase in temperature has a slowing effect on pipeline corrosion, reaching a peak value at 40°C. The response of corrosion rate to the concentration of corrosive gases follows a linear pattern. Based on these observations, we propose an effective corrosion control scheme.

Smart Sterilization Container Technology: Blue Wrap Innovation

Steam sterilization is the basis of modern surgical instrument sterilization. It is a highly effective, safe, cost-effective heat transfer method that is closely monitored and regulated. The autoclave time is typically 1 hour for sterilization and requires direct steam contact with surgical tray contents. A porous barrier, typically blue polypropylene wrap or filter, is required around or on the walls of the sterilized tray to allow steam to enter and escape. This barrier can require up to 2 hours of cooling without touching after autoclave sterilization to prevent moisture condensation and bacterial wicking. The porous barrier is fragile and can tear or develop holes which can lead to OR challenges. It is also moisture sensitive and may be an underappreciated source of surgical site infections. Porous barrier technologies create inherent inefficiencies in sterile processing and OR turnover. Electronic container technology may possibly forego the porous barrier limitations and inefficiencies by capturing a sterile vacuum seal in the autoclave. A verifiable vacuum sealed container may eliminate limited handling while cooling and may increase sterile department efficiency and reduce operating room turnover. If the technology is reliable and consistent, it may offer a safer and more durable, transportable, monitorable, sustainable sterile processing alternative than current porous barrier technologies.

Analysis of the aspiration system and gas cleaning for the cooling zone of the sintering machine for phosphorite ore

This study describes the gas emission aspiration and purification system, which is a crucial component of the life support system for a mining and processing plant. The aspiration system aims to maintain favorable working conditions and prevent the increase of dust content and harmful emissions in the air of working areas beyond the maximum permissible values. This study addresses the cleaning of aspiration and gas emissions in the technological zones of sintering machines during the sintering of ore phosphate material. It provides technical solutions for cleaning gases during the sinter cooling process, considering the condensation of moisture from gases inside exhausters. The text also reveals the technological parameters for the functioning of foam apparatuses, cyclones, and splash catchers. The process of cleaning gases in the technological cooling zone of the sintering machine is carried out in two parallel foam apparatus, using both dry and wet methods.

Experiment and modeling of an improvised atmospheric water harvester for arid and semi-arid conditions

Freshwater scarcity is a severe challenge in arid and semi-arid climatic conditions wherein the water harvesting from the atmosphere using active cooling condensation technique (ACC) is the only option. In this regard, we performed extensive experiments on a classical atmospheric water harvester (AWH) that relies on moisture condensation via a typical 1TR refrigeration cycle. We developed a MATLAB-SIMULINK based AWH model to note that the classical system has reasonable water harvesting rates in humid climates, but is inadequate for arid and semi-arid climatic conditions. We add an ultrasonic humidifier (160 W power input) before the evaporator section of the classical AWH system to address this issue. The modified system only needs a small amount of water (≈250 ml) for start-up, and further operates without perpetual water supply. We measure the water overflow from the humidifier tank (subtract the water added via the humidifier from the total water harvest) to show a net water harvesting in extremely hot and dry conditions (49 °C DBT and 12 % RH) resembling the weather conditions of Jaisalmer, India. A significant improvement of up to 70 % in water harvesting was also observed under warm and dry climates (35 °C DBT and 21 % RH) mimicking Jaipur, India. We believe that our system shows path for developing active AWH systems with substantial water harvesting in arid climates where active moisture condensation using the conventional strategy is otherwise not possible.

Scalable post-treatment for improved self-assembled monolayer coverage in perovskite solar cells

The Cooled Moisture Condensation (CMC) process improves MeO–2PACz coverage on FTO by increasing surface hydroxyl groups and minimizing oxygen vacancies, resulting in more uniform self-assembled monolayer coverage and enhanced solar cell performance.

Method of arrangement of internal thermal insulation of external protective structures of the room

This article aims to discuss the conditions of insulation and avoidance of moisture condensation in the enclosing structures of buildings whose facades cannot be insulated from the outside due to historical and cultural value. The paper presents a study of the energy-efficient design of the facade of a residential building, which uses insulating materials that are suitable for internal thermal insulation of historical buildings. The analysis of domestic and European literary sources regarding the improvement of the level of thermal protection of buildings shows that the improvement of energy efficiency is important for ensuring a sustainable, affordable and safe energy system. The paper presents the results of a study aimed at increasing energy efficiency in residential buildings, as well as an analysis of the humidity state and the possibility of condensation when using internal insulation. Numerical simulations were performed to confirm the results. The obtained results indicate that the use of mineral insulation "BETOL®" and aluminium foil as a vapour barrier, applied from the inside, contributes to the improvement of thermal insulation of the walls and reduces the risks of condensation. Computer simulations have shown that under the considered conditions, condensation does not occur. The relative humidity in the structure does not reach 90%. The same structure without the vapour barrier causes condensation because the relative humidity exceeds 100 % in whole thickness of the brickwork, which will cause destruction of the historical structure. This research makes an important contribution to the development of energy-efficient solutions for the construction industry, as it will ensure the minimum permissible value of the heat transfer resistance of the enclosing structures and extend the service life of them and buildings as a whole.

Quality Analysis of Bonded Joints in the Renovation of Plastic Automotive Parts

In the field of automotive parts, bonded joints are finding more and more applications. One of the main advantages of these joints is their non-destructive bonding. Due to them being permanently applied and being exposed to external operating conditions, their strength properties are reduced, especially when it comes to parts forming the functional unit of a car after renovation. It is, therefore, important to be able to understand these influences, which can help us to understand the extent to which these plastic parts are affected by external operating conditions after renovation. This article shows the various influences that these plastic parts produced using bonding technology and what they can be exposed to. For the evaluation of bonded joints, the following environments simulate the operating condition: SO2 concentration at total moisture condensation, 20% salt solution, and exposure in atmospheric conditions for one year in the environment. The best values among MEGABOND 2000, ChS EPOXY, and DINITROL 860 adhesives are achieved by ChS EPOXY adhesive, which can be recommended for the renovation of plastic parts for the automotive industry.

Flame retardant biogenic building insulation materials from hemp fiber

AbstractBiogenic thermal insulation materials are in high demand because of its carbon‐sequestration nature. However, high flammability, moisture condensation, and relatively high thermal conductivity of biogenic material are major concerns for sustainable building applications. In this study, we report the fire‐retardant cellulose xerogel insulation nanocomposites derived from hemp fiber recycling and silica xerogel, in which the boric acid treatment improves its fire retardancy. The as‐prepared materials show a low thermal conductivity of 31.3 mW/m K, high flexural modulus of 665 MPa, hydrophobicity with the water contact angle of 115°, and fire retardancy with 30% weight loss over a period of burning time 10 min. Overall, this work provides an effective method for the synthesis of fire‐retardant biogenic thermal insulation materials and shows a promising way for next‐generation bio‐based insulation materials.