Historic preservation of Siheyuan in Beijing China for continued residential use in modern China.

Siheyuan is a classical architecture style of residential housing of Beijing citizens dating from the Ming Dynasty. The people of China are very familiar with Siheyuan, considering its history of more than 700 years. It is a very important cultural and historical relic, which is now suffering from urban renovation. Since most of the buildings were built many years ago, present day residents have problems with accessing modern amenities such as convenient water access, light limitations, and lack of privacy. This study proposes solutions for these issues to help residents live in a more convenient and modern condition by rearranging Siheyuan's layout, designing plumbing system, and adding energy saving equipment.--Abstract

Well Productivity Enhancement of High Temperature Heterogeneous Carbonate Reservoirs

Acidizing is one of the most popular techniques for well productivity enhancement during oil and gas production. However, the treatment method is not very effective when the wellbore penetrates through multiple layers of heterogeneous reservoirs. Uneven acid distribution always results in productivity enhancement under expectation. When such a well is drilled, the temperature of the well could be too high to keep the acid reaction under control. The acid used in the treatment fluid, most commonly HCl, would react with the tubular and the formation at a very high rate. Rather than creating long wormholes to bypass the damaged area, face dissolution, loss of pipelines, and potential damage are the outcomes after the treatment. Thus, several new techniques were proposed in this study to solve the issues discussed above. To address the heterogeneity of the reservoir, viscoelastic surfactants (VES) were used as diverting agents during acidizing treatments. A recently developed chelating agent, L-glutamic acid-N,N-diacetic acid (GLDA), was evaluated as a possible alternative for the traditional HCl. Coreflood tests and measurements of rheology properties of the treatment fluids were used to investigate the performance of the treatment fluids based on the two new systems. In total, two VES were evaluated for their diverting abilities. The first VES was based on amine oxide. It was found that the live VES-based acids had the highest apparent viscosity when the concentration of HCl was 5 wt%. During the coreflood tests, the VES-based acid was only able to build up pressure drop across the core at injection rates less than 1 cm_(3)/min. A significant amount of the VES was left inside the core after the treatment, which reduced the efficiency of production enhancement. The other VES, based on carboxysulfobetaine, can tolerate high temperatures up to 325°F. According to the viscosity measurements of the spent VES-based acid, the addition of various corrosion inhibitors lowered the fluid viscosity at temperatures above 150°F. Mutual solvent was able to break the wormlike micelles formed by the VES in the presence of calcium chloride. The diverting ability of the VES was proved through coreflood tests. For the GLDA-based treatment fluids, two additives were added into the system in effort to improve the efficiency of the treatments. Polymers and VES were added into the GLDA to achieve even fluid distribution during treatment. A significant viscosity increment was observed with the help of the viscosifier, which could expand the application of the GLDA

Investigation and Construction of Self-oscillating Systems

Self-oscillating reactions have been widely observed and studied since the last century because they exhibit unique behaviors different from the traditional chemical reactions. Self-oscillating systems, such as the Belousov-Zhabotinsky (BZ) reaction, oxidation reaction of CO on single crystal Pt, and calcium waves in the heart tissue, are of great interest in a variety of scientific areas. This thesis contributes to the understanding of wave transition in BZ reaction, and to possible applications of non-equilibrium behaviors of polymer systems. In BZ reaction, two types of wave patterns, target and spiral, are frequently observed. The transition from one to another is not fully understood. Hence, a systematic investigation has been performed here to investigate the mechanism by which heterogeneity affects the formation of wave patterns. A BZ reaction catalyst was immobilized in ion exchange polystyrene beads to form active beads. Then active and inactive beads with no catalyst loading were mixed together with various ratios to achieve various levels of heterogeneity. In the same reaction environment, different wave patterns were displayed for the bead mixtures. We observed a transition from target patterns to spiral patterns as the percentage of the active beads in the beads mixture decreased. The increase of the heterogeneity led to wave pattern transition. Heterogeneity hindered the propagation of target waves and broke them into wavelets that generated spiral waves. In an effort to develop practical applications based on non-equilibrium phenomena, we have established a novel drug delivery system. A proton generator Zirconium Phosphate (ZrP) was imbedded inside a pH sensitive polymer matrix, poly acrylic acid (PAA). Through the ion exchange with sodium cation (Na+), ZrP generates protons to control the swelling/shrinking behaviors of PAA. The drug encapsulated in the matrix can be released in a controlled manner by adjusting the supply of Na+. This system might be developed into vehicles to deliver drugs to specific targets and release at a proper time. This new delivery technique will be convenient and significantly increase the efficiency of medicines

Imbibition behaviors in shale nanoporous media from pore-scale perspectives

In shale reservoirs, spontaneous imbibition is an important mechanism of fracturing fluid loss, which has an important impact on enhanced oil recovery and water resource demand. However, spontaneous imbibition behaviors are more complicated to characterize and clarify due to the nanoscale effects of the boundary slip, oil-water interfacial slip, and heterogeneous fluid properties caused by intermolecular interactions. A nanoscale multi-relaxation-time multicomponent and multiphase lattice Boltzmann method was applied to investigate the water imbibition into oil-saturated nanoscale space. The effects of pore size, fluid-surface slip, water film, oil-water interfacial slip, water bridge, and pore structures on the imbibition behaviors in a single nanopore were investigated. Then, the spontaneous imbibition behaviors in nanoporous media based on the pore scale microsimulation parameters obtained from the molecular simulation velocity results were simulated, and the effects of water saturations on imbibition behaviors were discussed. The results show that as the water saturation increases from 0 to 0.1, the imbibition mass in nanoporous media increases because of the oil-water interfacial slip and a completely hydrophilic wall. As water saturation continues to increase, the imbibition mass decreases gradually because the existence of water bridges impedes the water imbibition.Document Type: Original articleCited as: Wang, H., Cai, J., Su, Y., Jin, Z., Wang, W., Li, G. Imbibition behaviors in shale nanoporous media from pore-scale perspectives. Capillarity, 2023, 9(2): 32-44. https://doi.org/10.46690/capi.2023.11.0

Longitudinal survey of microbiome associated with particulate matter in a megacity.

BackgroundWhile the physical and chemical properties of airborne particulate matter (PM) have been extensively studied, their associated microbiome remains largely unexplored. Here, we performed a longitudinal metagenomic survey of 106 samples of airborne PM2.5 and PM10 in Beijing over a period of 6 months in 2012 and 2013, including those from several historically severe smog events.ResultsWe observed that the microbiome composition and functional potential were conserved between PM2.5 and PM10, although considerable temporal variations existed. Among the airborne microorganisms, Propionibacterium acnes, Escherichia coli, Acinetobacter lwoffii, Lactobacillus amylovorus, and Lactobacillus reuteri dominated, along with several viral species. We further identified an extensive repertoire of genes involved in antibiotic resistance and detoxification, including transporters, transpeptidases, and thioredoxins. Sample stratification based on Air Quality Index (AQI) demonstrated that many microbial species, including those associated with human, dog, and mouse feces, exhibit AQI-dependent incidence dynamics. The phylogenetic and functional diversity of air microbiome is comparable to those of soil and water environments, as its composition likely derives from a wide variety of sources.ConclusionsAirborne particulate matter accommodates rich and dynamic microbial communities, including a range of microbial elements that are associated with potential health consequences