With the application of high-precision, enormous rotating equipment and the addition of harsh working conditions, the advantages of dry gas sealing technology are increasingly obvious. Herein, research on the dynamic stability of dry gas seals is reviewed based on their operating mechanism. The influence of the dry gas seal structure, vibration response, and dynamic followability on the reliability of the shaft end sealing system of rotating machinery is the focus of current dry gas sealing technology. This work reviews the research history; analyzes the key coefficient of instability of the sealing system under external disturbances and the existing research on stability models; discusses the influence of starting and stopping characteristics, working conditions, and groove parameters on the stability of dry gas seals; and points out the shortcomings in the existing research. In addition, potential developments in dynamic stability are proposed, including improving model accuracy, improving experimental techniques, or applying intelligent control and optimization methods to enhance the dynamic stability of the sealing system. Finally, the development prospects for dry gas sealing technology in intelligent monitoring and wide temperature range adaptations are discussed, and theoretical guidance for improving the dry gas seal system is provided.

Abstract In order to reduce the failure accidents of conventional packers, a kind of sealing structure of retrievable packers is designed, which can provide reference for optimizing the sealing performance and pressure capacity of packers. And theoretical calculation and experimental research on its sealing performance and pressure capacity are carries out through the finite element analysis on the contact with large deformation based on Abaqus and experimental. The results show that when the rubber cylinder of retrievable packers in the sealing process, the upper packer is subjected to greater stress and mainly plays a sealing role. In order to improve the sealing performance of packer, the height of upper and lower packer should be preferentially selected about 60 mm, the height of middle rubber cylinders should be about 50 mm, and the thickness of packer should be about 21 mm. The newly designed rubber cylinders can meet 150 ℃. Sealing and pressure-bearing function under the condition of 10000 Psi. The rubber cylinder of newly designed can satisfy the function of sealing and pressure-bearing under 140 ℃ and 10000 Psi. The whole experiment shows that the capacity of bearing pressure and sealing is stable, which can better meet the requirements of field use.

Hydrogen is believed to be the principal domain of sustainable energy drive as an alternative to fossil fuels. Unlike the existing standards and knowledge for other fuels, the integrity of sealing and storage materials under the hydrogen environment is not comprehensively studied due to the comparatively new technology and lack of standard laboratory protocols. Typically, storage and polymer materials used as sealing experience degradation and damage in different ways over time in the exposure of hydrogen at different operating conditions, called aging. Improved understanding of the physical and chemical mechanism of degradation due to gaseous hydrogen atmosphere; helps to select and develop the materials best suited to carrier and sealing for respective applications. Damage to materials from aging is inevitable in high-pressure hydrogen gas exposure. This review discusses the mechanism of different categories of aging of storage and sealing materials under the hydrogen environment. Also, the article approaches discussing different laboratory test methods for each type of aging simulation. It covers the limitation of current research on determining material integrity through existing techniques of aging experiments and also explores the latest development. Important improvements are suggested in terms of materials development and testing procedures to meet the existing knowledge in the literature.

Photoelectrochemical systems have the potential to contribute to de-carbonation of the energy system because solar energy can be directly converted to hydrogen which can be burnt without the release of greenhouse gases. However, meaningful deployment of photoelectrochemical (PEC) technology in the global energy system, even when highly efficient scaled up devices become available, shall only be a reality when their safe and reliable operation can be guaranteed over serveral years of service life. The first part of the review discusses the importance of hermetic sealing of up scaled PEC device provided by the casing and sealing joints from a reliability and risk perspective. The second part of the review presents a survey of fully functional devices and early demonstrators and uses this to establish the extent to which the state of the art in PEC device design address the issue of hermetic sealing. The survey revealed that current material choices and sealing techniques are still unsuitable for scale –up and commercialization. Accordingly, we examined possible synergies with related photovoltaic and electrochemical devices that have been commericalised and derived therefrom, recommendations for future research routes that could accelerate the development of hermetic sealings of PEC devices.

Abstract: Unusual methane emission and spontaneous combustion of coal induced by the air leakage are both hazards during mining. The most common practice has been to improve mine safety is sealing the mining fractures. In this paper, the methane and geology, coal spontaneous combustion characteristics and the coexistence of methane emission and spontaneous combustion of coal were analyzed. The preparation system of inorganic solidified foam (ISF) in field applications is studied and the working principle of generating device consists of foam generator and mixer was expounded. The technical plan of site construction is that the foam fluids was injected to respectively seal the mining fractures behind hydraulic supports, the cavities of air return corner, and the fractures nearby the coal pillar. After the foam fluids injection, the two stress values in the coal pillar eventually maintained above 15.5Mpa and 13Mpa, respectively. It indicated that the ISF can enhance the bearing stress ability of the coal pillar by transforming the stress state from two dimensional to three dimensional. The methane concentration in the air return corner and air return roadway declined significantly to 0.63% and 0.25%. The differential pressure inside and outside of the 4301(1) goaf fluctuated between -100pa to 150pa and the concentration of CO and O2 declined to 9ppm and 6%. The CO concentration in the air return corner finally reached a stable level of 6ppm. What that all means, the foam fluids can seal the air leakage and inhibit spontaneous combustion of coal effectively.

Laboratory experiments were performed to measure the supercritical CO2 (scCO2) storage ratio (%) of the conglomerate and sandstone in Janggi Basin, which are classified as rock in Korea available for CO2 storage. The scCO2 storage capacity was evaluated by direct measurement of the scCO2 amount replacing pore water in a reservoir rock core. The scCO2 sealing capacity of the cap rock (i.e., tuff and mudstone), was also compared by measuring the initial scCO2 seepage pressure (Δp) into the rock core. The measured average scCO2 storage ratio of the conglomerate and the sandstone in Janggi Basin was 30.7 % and 13.1 %, respectively, suggesting that the scCO2 storage capacity is greater than 360,000 metric tons in the Janggi Basin. The initial scCO2 seepage pressure of the tuff in the Janggi Basin was 15 bar and continuous scCO2 injection into the tuff core occurred at Δp higher than 20 bar. For the mudstone, the initial scCO2 seepage pressure was higher than 150 bar (10 times higher than that of the tuff), demonstrating that the mudstone is more suitable than the tuff to shield scCO2 leakage from the reservoir rock in the Janggi Basin.

The steel grid structure with bolted ball joints is gaining popularity in offshore platforms and aquaculture cages, but the corrosion resistance of these joints is a critical safety concern. This article introduces an innovative method to enhance the sealing performance of bolted ball joints, preventing seawater ingress and corrosion. The approach involves creating a sealed surface within the contact gap between the sleeve and connecting components. Circular grooves and sealing washers are added to both ends of the sleeve. A two-dimensional finite element analysis model of the bolted ball joint with the sealing structure was created using SOLIDWORKS and ANSYS. The study analyzes the sealing gasket's contact pressure at various compression levels and evaluates its performance with bubble tests for air tightness. Research results show a linear relationship between contact pressure and compression rate, with a sealing pressure of 5.95MPa achieved at a 14% compression rate. This simple, cost-effective sealing method effectively prevents corrosion from seawater, making it ideal for marine environments.

During shearer operation, piston rod is susceptible to wear from invasion of pollutants, and then ruins sealing ring in hydraulic cylinder. This work attempts to conduct a systematical investigation of Cu-DLC (Cu-doped Diamond-like Carbon) film to improve the seal performance. Failure process of hydraulic cylinder was analyzed, and relevant parameters were determined. Several Cu-DLC films were deposited on the substrate of piston rod in a multi-ion beam assisted system, and their structures and combined tribological performances were investigated. As a result, dust particles attached to the piston rod may enter the cylinder, and damage the sealing ring under the radial force. Cu grains prefer to orientate (111) crystal plane with increase of Cu content, and may induce drop of hardness and internal stress for the film. Friction coefficient of the film ranges from 0.04 to 0.15, and rise of IG/ID ratio from 1.4 to 2.3 in Raman data indicates that bond transition from sp3-C to sp2-C may lower the friction coefficient. Modification mechanism of Cu-DLC film for the seal performance may come from synergistic effects of (i) contact force and friction heat induce the film graphitization, (ii) Cu doping improves toughness of the film and acts as a solid lubricant, and (iii) transfer layer plays a role of self-lubrication.

The civil construction industry is one of the sectors that most consume natural resources in the world and, consequently, one of that generate more waste. Thinking about constructive techniques that generate less impact on the environment is vital to ensure sustainable development. In this scenario, the Life Cycle Assessment (LCA) has been presented as an internationally recognized approach, that assesses the potential impact of products and services on human health and the environment, throughout its entire life cycle. Aimed to identify construction techniques and vertical closing systems that generate less impact and consumption of natural resources, the impacts generated by the life cycle of the three vertical closing systems most applied in construction sites in Brazil were compared: ceramic brick masonry system (CBr); concrete block masonry system (CBk); and structural blocks masonry system (SBk). The SBk proved to be the least impacting to the “Resource Scarcity”, “Damage to Human Health”, and “Damage to the diversity of Ecosystems” interesting areas. This performance is directly related to the use of cement CPIII type and also by the fact that the SBk consumes less concrete and mortar than the others. Already the "Water Consumption" area, the CBk was the least impacting due to the lower consumption of electricity during its life cycle. The reliability of the results was proven through a sensitivity analysis of the normalization and characterization factors, which consisted of comparing the results obtained by applying two different methodologies. It is believed that the LCA study carried out can assist in the decision-making process regarding the choice of the most sustainable construction method.

Even though hard, low friction coatings such as diamond like carbon (DLC) would be beneficial for the per-formance and longevity of rubber seals, a crucial challenge – as graphically illustrated in Figure 1.a – remains. The elastic mismatch of rubber substrate and DLC coating prevents a fracture free coating application. In this work a nature inspired approach (Figure 1.b) is applied to render the stiff coating flexible and resilient to delamination at the same time by direct patterning. Rubber substrates were laser structured with tile patterns and subsequently DLC-coated. Tensile and tribology tests were performed on structured and unstructured samples. Unstructured DLC-coatings showed a crack pattern induced by the coating process, which was further fragmented by tensile stress. Coatings with tile patterns did not experience a further fragmentation under load. During continuous tribological loading, less heterogenous damage is produced for tile structured samples. The findings are ascribed to the relief of induced coating stress by the tile structure, meaning a more resilient coating.

Our work is regarding the analysis of land use changes, in the light of “saving soil” against the expansion due to unearned plus value of land: The loss of natural and agricultural surface in front of the expanding urban environment is a critical aspect of unsustainability of urban development, especially in the way it was carried out in the past decades. The measure of the physical transition of land use and characters from a more natural condition of land surface to a new artificial one, joint with a parallel analysis of the increase of land value due to such change is nowadays a major land-policy tool. The interplay of urban economics regulation with planning, reveals new key issues in urban governance and environmental preservation. In this paper it will be shown some experiment about the impact assessment of soil take, related with the seek of valorization of property inside the planning process. Our paper reports as well about the experimental activity carried out inside the MITO Lab of the Polytechnic of Bari, where reports about property values and environmental values have been produced, specially looking at the reality of the Apulia, a southern Italian Region, that is rich of farmlands and coastlines, often invaded by constructions with a severe loss of nature, landscape and ecosystems services.

Prefabricated forms of construction have led to the rapid onsite assembly of buildings however there are still on-site tasks and processes which can be reevaluated and redone specifically in keeping with the principles of prefabrication instead being adapted to fit its purpose. One such process is that of waterproofing between prefabricated panels and modules which come from the factory fully complete façade and all. Conventional means of waterproofing can be used however it results in more work done on site, potential delays and generally requires access from the external face of the building. This paper presents the Modelling, Implementation and Evaluation of purpose developed weatherproof seals specific for Prefabricated Construction. An overview is provided of the entire development process and specific focus is given to the modeling using FEA computer simulations, manufacturing and testing which then resulted in the implementation in a prefabricated panelised building which is used as a case study and the means of further evaluation. These strategies have enabled an efficient and robust prefabricated waterproofing solution specific for this form of construction to be understood and implemented. The resulting case study has successfully verified the time and cost savings when compared to conventional techniques whilst still providing a durable and effective weatherproof seal for prefabricated panelised and modular systems.

Satisfactory weatherproofing of buildings is vital to maximise their design life and performance which requires the careful design of external sealing technologies. Systems commonly available have served well in conventional construction however with many prefabricated systems emerging in the building industry new and novel means of weatherproofing between panels and modules need to be developed purpose specific to this application. This paper presents a holistic and fundamental methodological approach to Design and Development of waterproof seals and has been applied specific for prefabricated panelised and modular systems. Two purpose specific weatherproof seals are finally presented. Flow charts of the overview of the suggested methodological approach and the processes within which include DfMA that have been incorporated into understanding and developing seals for this practical application. These strategies have enabled a resourceful and holistic set of processes that can be adapted and used for similar forms of product research in new and developing areas of construction such as prefabrication. The design and development process is thoroughly explored and has resulted in an exploration of the technical challenges and potential solutions which take into consideration factors from installation limitations to building tolerances.