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Enhancement of sludge gravitational thickening with weak ultrasound

Panyue ZHANG, Tian WAN, Guangming ZHANG

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 753-760 doi: 10.1007/s11783-011-0368-5

摘要： Gravitational thickening is the prevailing method to reduce sludge volume but the process is slow and usually requires addition of polyelectrolyte(s). This paper investigated the potential benefits of sonication on enhancing the sludge gravitational thickening with very low energy dose, so called “weak ultrasound”. Results showed that weak sonication significantly changed the sludge settlability and the main mechanism was release of the loosely bounded extracellular polymeric substances. The changes in sludge behaviors by sonication were strongly influenced by power density and sonication duration. Lower sound frequency was slightly better than higher frequency. Weak sonication (<680 kJ·kg DS) improved the sludge gravitational thickening while high ultrasonic energy deteriorated the process. Considering both the sludge thickening efficiency and energy consumption, the optimum conditions were 0.15 W·mL , 7 s, and 25 kHz. Under such conditions, the energy dose was only 155 kJ·kg DS, much lower than literature reports, and the sludge settling time was shortened from 24 h to 12?h. Weak sonication could substitute expensive polyelectrolyte coagulant for sludge thickening. Combination of weak sonication and polyelectrolyte could further reduce the settling time to 6 h. The final water content of the thickened sludge was not changed after sonication or polyelectrolyte addition.

关键词： activated sludge sonication settlability dry weight extracellular polymeric substances polyelectrolyte

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Application of cable-supported spatial grid in dry coal shed

XING Haidong, HAO Jiping, XU Guobin

《结构与土木工程前沿（英文）》 2008年第2卷第1期页码 26-29 doi: 10.1007/s11709-008-0008-8

摘要： This paper presented a new structural style cable-supported spatial grid, which was applied in large span dry coal sheds. The influence of configuration of cable on the force of cable and beam, the ratio of beam force to cable force and the deflection of span was investigated, and a rational configuration of cable was obtained. The results show that the cable-supported spatial grid can maximize the use of material strength, and have the advantages of low usage of steel, large span and sufficient headroom.

关键词： dry material strength low rational configuration influence

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Influence of HS and NH on biogas dry reforming using Ni catalyst: a study on single and synergetic effect

《环境科学与工程前沿（英文）》 2023年第17卷第3期 doi: 10.1007/s11783-023-1632-1

摘要：

● NH₃ in biogas had a slight inhibitory effect on dry reforming.

关键词： Biogas Dry reforming Sulfur poisoning Ammonia Synergetic effect Hydrogen

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promotes macrophage pyroptosis by driving the glycolytic reprogramming of corneal epithelial cells in dry

《医学前沿（英文）》 2023年第17卷第4期页码 781-795 doi: 10.1007/s11684-023-0986-x

摘要： Tear film hyperosmolarity plays a core role in the development of dry eye disease (DED) by mediating the disruption of ocular surface homeostasis and triggering inflammation in ocular surface epithelium. In this study, the mechanisms involving the hyperosmolar microenvironment, glycolysis mediating metabolic reprogramming, and pyroptosis were explored clinically, in vitro, and in vivo. Data from DED clinical samples indicated that the expression of glycolysis and pyroptosis-related genes, including PKM2 and GSDMD, was significantly upregulated and that the secretion of IL-1β significantly increased. In vitro, the indirect coculture of macrophages derived from THP-1 and human corneal epithelial cells (HCECs) was used to discuss the interaction among cells. The hyperosmolar environment was found to greatly induce HCECs’ metabolic reprogramming, which may be the primary cause of the subsequent inflammation in macrophages upon the activation of the related gene and protein expression. 2-Deoxy-d-glucose (2-DG) could inhibit the glycolysis of HCECs and subsequently suppress the pyroptosis of macrophages. In vivo, 2-DG showed potential efficacy in relieving DED activity and could significantly reduce the overexpression of genes and proteins related to glycolysis and pyroptosis. In summary, our findings suggested that hyperosmolar-induced glycolytic reprogramming played an active role in promoting DED inflammation by mediating pyroptosis.

关键词： dry eye disease glycolytic reprogramming pyroptosis inflammation 2-DG

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Characteristics of pollutants behavior in a stormwater constructed wetland during dry days

Jianghua YU, Kisoo PARK, Youngchul KIM

《环境科学与工程前沿（英文）》 2012年第6卷第5期页码 649-657 doi: 10.1007/s11783-012-0426-7

摘要： A stormwater wetland treating non-point source pollution (NPS) from a 64 ha agricultural watershed was monitored over a period of five months. The results indicated that pH and dissolved oxygen (DO) were increased in the wetland due to the algal growth. The highest total suspended solids (TSS) concentration was observed in the aeration pond due to the resuspension of solids, decreased in the wetland. The respective decreases in total nitrogen (TN) and total kjeldahl nitrogen (TKN) were 15.9% and 28.7% on passing through the wetland. The nitrate and ammonia were increased by 45.4% and decreased by 79.9%, respectively. These variations provided strong evidence for the existence of nitrification. The total phosphorus (TP) and phosphate had respective reductions of 52.3% and 58.2% over the wetland. The total chemical oxygen demand (TCOD) and soluble chemical oxygen demand (SCOD) were also decreased. Generally, the TN, TP and phosphate removal efficiencies were positive. These positive removal efficiencies were mainly due to microbial activities, uptake by plants, and chemical precipitation at high pH. Negative removal efficiencies can be caused by continuous rainfall activities, with short antecedent dry days (ADDs) and unstable hydraulic conditions, some other biogeochemical transformations and algal growth also being important parameters.

关键词： constructed stormwater wetland dry days nitrification and denitrification pollutants characteristic

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Acupuncture for the management of dry eye disease

《医学前沿（英文）》 2022年第16卷第6期页码 975-983 doi: 10.1007/s11684-022-0923-4

摘要： The effectiveness of using acupuncture for dry eye disease (DED) is controversial. Thus, this systematic review investigated the effectiveness and feasibility of using acupuncture for DED in accordance with the 2020 PRISMA statement. The outcomes of interests were (1) to evaluate the efficacy of acupuncture in improving the ocular surface disease index (OSDI), Schirmer I test score, and tear breakup time from baseline to the last follow-up; (2) to determine possible complications of using acupuncture; and (3) to investigate the superiority of acupuncture over other commonly used treatments for DED. Data from 394 patients were collected. Results showed that acupuncture significantly prolonged the tear breakup time (P < 0.0001), significantly increased the Schirmer I test score ( P < 0.0001), and significantly reduced the OSDI ( P < 0.0001) from baseline to the last follow-up. Compared with the control group, the acupuncture group had significantly greater Schirmer I test score ( P < 0.0001), significantly longer tear breakup time ( P = 0.0004), and significantly lower OSDI (P = 0.002). These results suggest that acupuncture is effective and feasible in improving symptoms and signs of DED. No severe adverse effects of acupuncture were observed.

关键词： dry eye disease xerophthalmus acupuncture

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Seismic behavior of cantilever wall embedded in dry and saturated sand

Sanku KONAI, Aniruddha SENGUPTA, Kousik DEB

《结构与土木工程前沿（英文）》 2020年第14卷第3期页码 690-705 doi: 10.1007/s11709-020-0615-6

摘要： The embedded cantilever retaining walls are often required for excavation to construct the underground facilities. Significant numbers of numerical and experimental studies have been performed to understand the behavior of embedded cantilever retaining walls under static condition. However, very limited studies have been conducted on the behavior of embedded retaining walls under seismic condition. In this paper, the behavior of a small scale model embedded cantilever retaining wall in dry and saturated sand under seismic loading condition is investigated by shake table tests in the laboratory and numerically using software FLAC2D. The embedded cantilever walls are subjected to sinusoidal dynamic motions. The behaviors of the cantilever walls in terms of lateral displacement and bending moment are studied with the variation of the two important design parameters, peak amplitude of the base motions and excavation depth. The variation of the pore water pressures within the sand is also observed in the cases of saturated sand. The maximum lateral displacement of a cantilever wall due to seismic loading is below 1% of the total height of the wall in dry sand, but in case of saturated sand, it can go up to 12.75% of the total height of the wall.

关键词： embedded cantilever wall shake table test FLAC2D seismic loading saturated and dry sand

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Use of dry yeast cells as a cheap nitrogen source for lactic acid production by thermophilic

Kim Yng Ooi, Jin Chuan Wu

《化学科学与工程前沿（英文）》 2015年第9卷第3期页码 381-385 doi: 10.1007/s11705-015-1534-2

摘要： Dry yeast cells (DYC) were used as a cheap nitrogen source to replace expensive yeast extract (YE) for L-lactic acid production by thermophilic . Cassava starch (200 g·L ) was converted to L-lactic acid by simultaneous saccharification and fermentation using WCP10-4 at 50 °C in the presence of 20 g·L of DYC, giving 148.1 g·L of L-lactic acid at 27 h with a productivity of 5.5 g·L ·h and a yield of 92%. In contrast, 154.4 g·L of lactic acid was produced at 24 h with a productivity of 6.4 g·L ·h and a yield of 96% when equal amount of YE was used under the same conditions. Use of pre-autolyzed DYC at 50 °C for overnight slightly improved the lactic acid titer (154.5 g·L ) and productivity (7.7 g·L ·h ) but gave the same yield (96%).

关键词： L-lactic acid thermophilic strain Bacillus coagulans dry yeast cells autolysis fermentation

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Laboratory study on high-temperature adsorption of HCl by dry-injection of Ca(OH)

Junjun TAN,Guohua YANG,Jingqiao MAO,Huichao DAI

《环境科学与工程前沿（英文）》 2014年第8卷第6期页码 863-870 doi: 10.1007/s11783-013-0618-9

摘要： Combustion-generated hydrogen chloride (HCl) is considered to be a very hazardous acid gaseous pollutant. This paper presents a laboratory study on the dry adsorption of HCl. The experiments were conducted in a dual-layer granular bed filter, at gas temperatures of 500°C–700°C and (Ca)/ (Cl)molar ratios of 1.0–5.0 using the silver nitrate titration method by dry adsorbent powders Ca(OH) . Mainly, the adsorption efficiency of HCl and utilization efficiency of Calcium were studied, by varying relevant factors including (Ca)/ (Cl), temperature, feeding method, water vapor and CO . With a relatively higher HCl concentration of 1000 ppm, the experimental results revealed that 600°C may be the optimum temperature for HCl adsorption when optimum (Ca)/ (Cl) was 2.5 in our tests. The results also demonstrated that the feeding at a constant pressure was more effective, and the HCl adsorption efficiency could rapidly reach over 90% with (Ca)/ (Cl) = 2.5 at 600°C. Furthermore, the HCl adsorption efficiency was found to be slightly promoted by water vapor, while could be impeded by CO , and the utilization efficiency of calcium could be up to 74.4% without CO , while was only 36.8% with CO when (Ca)/ (Cl) was 2.5 at 600°C.

关键词： acid gas HCl Ca(OH)₂ dry adsorption high temperature dual-layer granular bed filter

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Solving topology optimization problems by the Guide-Weight method

Xinjun LIU, Zhidong LI, Liping WANG, Jinsong WANG

《机械工程前沿（英文）》 2011年第6卷第1期页码 136-150 doi: 10.1007/s11465-010-0126-6

摘要：

Finding a good solution method for topology optimization problems is always paid attention to by the research field because they are subject to the large number of the design variables and to the complexity that occurs because the objective and constraint functions are usually implicit with respect to design variables. Guide-Weight method, proposed first by Chen in 1980s, was effectively and successfully used in antenna structures’ optimization. This paper makes some improvement to it so that it possesses the characteristics of both the optimality criteria methods and the mathematical programming methods. When the Guide-Weight method is applied into topology optimization, it works very well with unified and simple form, wide availability and fast convergence. The algorithm of the Guide-Weight method and the improvement on it are described; two formulations of topology optimization solved by the Guide-Weight method combining with SIMP method are presented; subsequently, three numerical examples are provided, and comparison of the Guide-Weight method with other methods is made.

关键词： Guide-Weight method topology optimization SIMP method

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A decoupled method to identify affecting mechanism of crosswind on performance of a natural draft dry

Weiliang WANG, Junfu LYU, Hai ZHANG, Qing LIU, Guangxi YUE, Weidou NI

《能源前沿（英文）》 2020年第14卷第2期页码 318-327 doi: 10.1007/s11708-019-0627-x

摘要： The natural draft dry cooling tower (NDDCT) has been increasingly used for cooling in power generation in arid area. As crosswind affects the performance of a NDDCT in a complicated way, and the basic affecting mechanism is unclear, attempts have been made to improve the performance of a NDDCT based on limited experiences. This paper introduces a decoupled method to study the complicated crosswind effects on the inlet and outlet of a NDDCT separately by computational fluid dynamics (CFD) modeling and hot state experiments. Accordingly, the basic affecting mechanism of crosswind on the NDDCT performance is identified. Crosswind changes the inlet flow field of a NDDCT and induces mainstream vortices inside the tower, so as to degrade the ventilation. Besides, low crosswind deflects the upward plume at the outlet to further degrade the ventilation, while high crosswind induces the low pressure area at the outlet to reduce the ventilation degradation.

关键词： affecting mechanism crosswind decoupled method mainstream vortices natural draft dry cooling tower (NDDCT) degradation

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Assessment of metals in dry-toilet collected matters from suburban areas of Ulaanbaatar, Mongolia, using

Xuan LIU,Zifu LI,Eric BOSC,Heinz-Peter MANG

《环境科学与工程前沿（英文）》 2014年第8卷第5期页码 710-718 doi: 10.1007/s11783-013-0592-2

摘要： Dry-toilet collected matter (DCM) from traditional dry-toilet pits are a potential health and ecological risk in suburban areas. In this study, the characteristics of metals in DCMs from suburban areas of Ulaanbaatar were surveyed. The results indicate that DCMs contain a high percentage of organic matter and nutrients, while heavy metals are at low levels, which shows good agricultural potential. The concentration ranges of Cr, Cu, Hg, Ni, Pb, and Zn were 11±5, 46±9, 0.08±0.05, 9±3, 17±9, and 338±86 mg·kg , respectively. The concentration of Cd was below 0.5 mg·kg , and a high positive relation was shown between chromium and nickel concentrations. The heavy metals in DCMs were safe for land application but Zn in DCMs was close to the effects range median (ERM), which is toxic in some cases, such as amphipod bioassays. Because it is mandatory to treat DCMs to reduce pathogens, in the case of heavy metal enrichment and agricultural reuse, composting or pyrolysis are better choices than incineration. Compared with global soil background values, the heavy metals in DCMs showed a low level of ecological risk, but a medium level when compared with Mongolian soil background values. The ecological risk of six heavy metals was in the descending order Hg>Cu>Zn>Pb>Ni>Cr and the contribution rate of Hg exceeded 60%.

关键词： heavy metals suburban areas dry-toilet risk assessment

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A wind tunnel study on control methods for cable dry-galloping

Hung D. VO,Hiroshi KATSUCHI,Hitoshi YAMADA,Mayuko NISHIO

《结构与土木工程前沿（英文）》 2016年第10卷第1期页码 72-80 doi: 10.1007/s11709-015-0309-7

摘要： The common vibration of cable caused by rain-wind combination has been known as most typical type and a lot kind of its countermeasures has been proposed for suppressing this phenomenon. Recently, stayed-cables were also proved that they could be excited in dry state (without rain), which is called dry-galloping. Recently, its mechanisms have been explained by axial flow, Reynolds number and so on. To clarify the characteristics of this galloping, wind tunnel test of a cable model with various kinds of wind angle was conducted. Then, three types of countermeasure were examined to suppress dry- galloping of bridge cable. The tests confirmed that the occurrence of dry-galloping depends on relative wind attacked angles and onset reduced wind speed. Furthermore, single spiral wire, double spiral wire and circular ring were found to have high effectiveness in mitigating this galloping when those are installed properly.

关键词： dry-galloping wind-relative angle single spiral wire double spiral wire circular rings

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Instantaneous deflection of light-weight concrete slabs

Behnam VAKHSHOURI, Shami NEJADI

《结构与土木工程前沿（英文）》 2017年第11卷第4期页码 412-423 doi: 10.1007/s11709-017-0416-8

摘要： Construction loading before the age of 28 d can have the most significant effects on the slabs, especially for multi-story structures. The changing properties of the young concrete complicate the prediction of serviceability design requirements also. An experimental investigation is performed on four simply supported Light-Weight Concrete (LWC) one-way slabs subjected to immediate loading at 14 d. Effects of aggregate type, loading levels and cracking moment together with the influences of ultimate moment capacity and service moment on the instantaneous deflection of slabs are studied. Comparison of the obtained results with predictions of existing models in the literature shows considerable differences between the recorded and estimated instantaneous deflection of LWC slabs. Based on sensitivity analysis of the effective parameters, a new equation is proposed and verified to predict the instantaneous deflection of LWC slabs subjected to loading at the age of 14 d.

关键词： instantaneous deflection light-weight concrete expanded polystyrene effective moment of inertia cracking moment moment capacity service moment

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friction and plastic deformation to machined surface temperatures and residual stress patterns in finish dry

Subhash ANURAG, Yuebin GUO,

《机械工程前沿（英文）》 2010年第5卷第3期页码 247-255 doi: 10.1007/s11465-010-0097-7

摘要： Temperature on the machined surface is critical for surface integrity and the performance of a precision component. However, the temperature of a machined surface is challenging for in-situ measurement. Furthermore, the individual contribution of tool/work friction and plastic deformation of work materials to surface temperature is very difficult to quantify because the measured temperature is always the resultant temperature. This lack of understanding on the temperature distribution blocks the design of effective cutting tool geometries and materials to minimize surface temperature. This study provides a finite element method based on a predictive model to decouple the contributions of tool/work friction and material plastic deformation to surface temperature in a dry cutting process. The study shows that the plastic deformation of work material contributes to the majority of surface temperature, whereas the tool/work friction contribution is secondary. High temperatures are produced when more materials are plowed under the cutting edge. A large tool/work friction leads to higher surface temperatures, and the use of a cutting tool with physical properties in process simulation significantly improves the accuracy of predicted surface temperatures. Residual stress reversal from subsurface maximum residual to surface maximum residual stress may occur when tool/work friction increases.

关键词： surface temperature friction residual stress finite element analysis (FEA) dry cutting tool property