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In this paper, based on the Wachspress generalized barycentric coordinates, we propose and analyze a polygonal finite volume element method (PFVEM) for solving the anisotropic diffusion equation on convex polygonal meshes. In particular, the PFVEM reduces to the classical P 1 -FVEM on triangular meshes and it is not identical to the classical Q 1 -FVEM on quadrilateral meshes. A new proof is given to Proposition 8 in [19] , a result that is crucial to the derivation of the interpolation error estimates in both H 1 and H 2 norms. The original proof is based on a certain geometric assumption, which is shown not always true by a counterexample given in this paper. Moreover, for the error analysis of the PFVEM, we prove the H 2 error estimate of the Wachspress interpolation. Under the coercivity assumption, the optimal H 1 error estimate for the finite volume element solution is obtained. Several numerical examples are presented to show the efficiency and robustness of the proposed method for the heterogeneous and anisotropic diffusion problems on polygonal meshes. [ABSTRACT FROM AUTHOR]

• A novel concrete cover delamination model is proposed. • Flat concrete surface and non-uniform distribution of rust are duly accounted for. • The interaction between neighboring corroded rebars is considered. • Bulging deformation of cover surface and volume of rust can be predicted manually. Cover delamination failure caused by the corrosion of closely spaced rebars is commonly found in deteriorated reinforced concrete (RC) structures. However, analytical studies carried out on this failure mode of RC structures are rare. In response, this paper proposes a novel analytical model for cover delamination which takes into account the interaction between the neighboring corroded rebars, non-uniform distribution of rust around the steel/concrete interface, and boundary conditions of the concrete surface. This simple model enables manual prediction of the bulging deformation of the cover surface and the maximum thickness of rust. The predicted results are then verified with numerically derived results from a nonlinear finite element analysis. Finally, the effects of the rebar spacing, tensile strength of concrete and cover thickness on the bulging of the concrete cover surface and the maximum thickness of rust are studied with the verified analytical model. [ABSTRACT FROM AUTHOR]

• Elastic-body-rotation model for simulating corrosion-caused cover cracking is proposed. • The width of surface cracks and bulging of cover are predicted. • The thicknesses of corroded steel for initiating and widening cracks are derived. • This simple model has been validated by available test results. A novel elastic-body-rotation model is proposed to analyze the mechanism and the process of cover cracking and spalling caused by the non-uniform corrosion of widely spaced reinforcements. The width of the cover surface cracks, bulging of the concrete surface and maximum thickness of the corroded steel can be predicted by using the proposed model. The predicted bulging of the concrete cover has been validated by the experimental and numerical results. Using the validated model, the effects of the diagonal crack angle, tensile strength of concrete and cover thickness on the bulging of the cover surface and the thickness of the corroded steel for initiating and widening cracks are investigated with a parametric study. It is found that the diagonal cracking angle has a major influence on the cover surface crack width. In addition, the degree of corrosion in rebars and the width of internal diagonal cracks can be evaluated by simply measuring the width of surface cracks or the bulging of cover surface. [ABSTRACT FROM AUTHOR]

Abstract The characteristic carmine red color due to heme proteins is always observed in enriched anammox biomass. Heme c is a very important co-factor participating the main metabolic reactions with catalytic and electron-transfer potential in the anammox bacteria, and is possible for use as an indicator to evaluate anammox performance. Knowledge of the relationship between the heme c concentration and the anammox reactor performance is, however, very limited available information is constrained at an operation temperature of 35 °C. In this study, we report the heme c concentration change along with nitrogen removal rate (NRR) in three anammox expanded granular sludge bed reactors operated at different temperatures (15, 25, 35 °C). The response of specific anammox activity (SAA) to temperature was revealed for biomass originating from three reactors. The results indicate a strong relationship between heme c concentration and NRR at different culture temperatures. The possibility of evaluating the anammox performance by combining heme c quantification and the temperature is revealed. Graphical abstract Unlabelled Image Highlights • Heme c was found as a good indicator of anammox performance evaluation. • Positive linear correlation was obtained between heme c and nitrogen removal rate. • Ca. kuenenia stuttgartiensis predominated in 3 reactors at different temperatures. • Heme c concentration in anammox process also depends on culture temperatures. [ABSTRACT FROM AUTHOR]

Phosphorus recovery from wastewater is an important approach for sustainable phosphorus use. In this work, a process combining anammox and hydroxyapatite (HAP) precipitation in an expanded bed reactor for simultaneous nitrogen removal and phosphorus recovery was developed by applying specific Ca/P ratio and pH control. A high phosphorus removal rate (0.14 ± 0.01 kg-P/m 3 /d) was obtained while a stable nitrogen removal efficiency (87.4 ± 2.9%) maintained with an effluent recirculation system applied. Average 13.4% phosphorus (30.7% in P 2 O 5 ) accumulation in the dry sludge and a Ca/P ratio very close to HAP was observed by quantitative elemental analysis. In this work, different analysis revealed the two layers structure with anammox biofilm attached to inorganic core of the granules. Different spectral analysis determined the major phase of the inorganic content as hydroxyapatite. With proper Ca/P ratio and pH control, anammox expanded bed reactor was transformed into an efficient process to simultaneously remove nitrogen and recover phosphorus. [ABSTRACT FROM AUTHOR]

The nitrogen loading rate (NLR) of an anammox attached film expanded bed (AAFEB) reactor was increased from 5.0 to 60.0 gN/L/d. During the stable operational period, the TN removal efficiency maintained at 87.3 ± 2.5%, and a maximum nitrogen removal rate (NRR) of 44.9 ± 0.3 gN/L/d was achieved. Overload resulted in the sharp deterioration of reactor performance, the ratio of (Food/Microorganism)/SAA should be maintained at lower than 66 ± 7% to ensure the stable operation of the AAFEB reactor. New stoichiometric equations for the anammox process under the low NLR condition (5.0 gN/L/d) and the high NLR condition (50.0 gN/L/d) were proposed. The quantitative SAA-cytochrome heme C relationship was established for the first time that providing a simple way for monitoring the reactor performance. Substrate tolerance ability was significantly increased that proving the stability of the AAFEB reactor was continuously enhanced during the stable operational periods. [ABSTRACT FROM AUTHOR]

Summary Previous literature suggests that social capital at the individual and community levels can contribute significantly to poverty reduction. In this paper we empirically investigate the relationship between social capital and households’ probability of living under poverty. We used a large-scale cross-sectional survey in western Chinese provinces to explore the impact of households’ social capital on four different poverty measures. Our results indicate that in addition to the structural and relational properties of households’ social networks, the types of resources embedded in these networks such as business ties, political ties, and appropriable social organizations can contribute significantly to poverty reduction. Moreover, since our study is situated in China’s emerging economy context, we can thus further explore how variations in macrolevel institutions affect the usefulness of various social resources in reducing poverty. We discovered that the quality of local institutions as measured by local residents’ trust toward the institutions can modulate the effectiveness of political ties and appropriable social organizations, such that the impacts of political ties and appropriable social organizations tend to diminish in communities with higher level of institutional trust than they are in communities with lower level of institutional trust, while business ties turn out to be effective in alleviating poverty in both high- and low-trust communities. [ABSTRACT FROM AUTHOR]

The accumulation of soluble microbial production (SMP) in an anammox attached film expanded bed (AAFEB) and its effect on the reactor performance were investigated in this study. During the long-term experiment, an extended HRT resulted in the accumulation of SMP and the change of treatment performance. When the SMP increased from 10.5 ± 1.5 mg L −1 to 31.7 ± 6.4 mg L −1 with the increase of influent TN concentration from 313 mg L −1 to 2500 mg L −1 , the TN removal efficiency was stable. However, when the influent TN concentration was 3500 mg L −1 , the SMP concentration increased higher than 100 mg L −1 , the reactor soon became inhibited. Bath tests indicated that both the specific anammox activity (SAA) and the substrate tolerance ability decreased during the stable operation phases, whereas the specific denitrification activity (SDA) was significantly enhanced. In addition, N 2 O emissions in the anammox-denitrifier symbiotic system were greater than in the conventional nitrogen removal process. [ABSTRACT FROM AUTHOR]

An anammox attached film expanded bed (AAFEB) reactor was operated to study the long-term performance and the variation of substrate tolerance ability. The results indicated that the nitrogen loading potential (NLP) was significantly enhanced from 13.56 gN·(L·d) − 1 to 20.95 gN·(L·d) − 1 during the stable operation period. The inhibitory concentration of 10% (IC 10 ) for free ammonia (FA), free nitrous acid (FNA) and SN inf (diluted substrate concentration) increased from 18 mg/L, 12 μg L −1 and 370 mg NL − 1 to 31 mg/L, 19 μg L −1 and 670 mg NL − 1 , respectively. However, the substrate shock of 2500 mg NL − 1 for 24 h terribly weakened the treatment performance and substrate tolerance ability of the reactor. The results of batch tests indicated that the existence of lag phase made the AAFEB reactor more vulnerable to substrate variation. The SN inf was accurate to be used to monitor the reactor performance and should be maintained below 320 mg NL − 1 to ensure the absolute stable operation. [ABSTRACT FROM AUTHOR]

The Early Cretaceous was a time with super-greenhouse conditions and episodic global oceanic anoxic events. However, relative timing of atmospheric CO 2 emissions and oceanic anoxic events, and their causal relationships remain matters of debate. Using the stomatal index approach, well-preserved fossil cuticles of Ginkgo from the Lower Cretaceous Changcai Formation, eastern Jilin, and from the Lower Cretaceous Yingcheng Formation, central Jilin, Northeast China, were investigated to reconstruct atmospheric CO 2 concentrations during the Aptian and earliest Albian (Early Cretaceous). The results indicate that the CO 2 concentrations reached 1098–1142 ppmv (Carboniferous standardization) or 970–1305 ppmv (regression function) during the Aptian and earliest Albian. Our estimates of palaeoatmospheric CO 2 concentrations during the earliest Albian (OAE 1b) are slightly higher than the data between the early Aptian Selli (OAE 1a) and the middle Aptian Fallot OAEs; this may indicate the absence of any great emissions of CO 2 during the latest Aptian and earliest Albian. [ABSTRACT FROM AUTHOR]

An Anaerobic ammonia oxidation (Anammox) expanded granular sludge bed (EGSB) reactor was investigated with a long-term continuous operation. The nitrogen removal performance and stability of process subjected to transient pH shock (decreased from 9.0 to 7.0 and maintaining for 24 h) were evaluated. In the steady stage, the nitrogen loading rate (NLR) and nitrogen removal rate (NRR) can reach to 10 and 8.5 kg-N m −3 d −1 , respectively. However, the system had a low tolerance for transient pH shock. The deterioration of the granule sludge properties and the inhibition of specific Anammox activity (SAA) resulted in the destabilization of the EGSB after pH shock. The main factors governing the treatment performance of EGSB were the high concentration of free nitrous acid (FNA) and free ammonia (FA). However, the lower than 10% reduction of ammonia removal can be maintained when FA and FNA were lower than 15 mg l −1 and 15 μg l −1 , respectively. The process was successfully recovered by controlling the FNA and FA concentration after the low pH shock. [ABSTRACT FROM AUTHOR]

To optimize the operation and know the relationships between operation and potential capability of UASB-anammox mixed culture process, reactor kinetic models were conducted and the potential nitrogen conversion rates were estimated. Total nitrogen (TN), NH 4 + -N and NO 2 − -N removal efficiency were simulated and predicted by modified Stovere-Kincannon model, Monod model, First-order model and Grau second-order substrate removal models. The nitrogen gas production rate was also evaluated by Van der meer and heertjes model. During the process, the nitrogen loading rate (NLR) was increased from 0.93 to 7.34 g L −1 d −1 following the substrate increased from 280 to 462 mg N L −1 and hydraulic residence times (HRT) decreased from 24 h to 1.5 h, the highest achieved removal efficiency of NH 4 + –N, NO 2 − –N and TN were 99, 95 and 90%, respectively. Simulation results proved that the Modified Stover-Kincannon model and the Grau second-order model were the most appropriate models with prospected maximum TN removal rate U max and saturation value constant K B were 3.33 and 4.03 g N L −1 d −1 , respectively. Validation of the linearity between the experimental data and predicted values of kinetics illustrated the two models appropriately described the kinetic behavior of UASB-anammox mixed culture. The reactor kinetic evaluation proved valuable information for guiding or optimizing the operation condition. [ABSTRACT FROM AUTHOR]

In this paper, a double-cylinder model with a consideration of concrete confinement effects is proposed to simulate reinforcement corrosion-caused cover cracking. The analytical model incorporates force equilibrium in both tangential and radial directions as well as volume expansion and deformation compatibility in the steel-rust-concrete interface. Confinement effects outside the cylinders are taken into account by comparing the numerical and available experimental results. Parametric studies are conducted to investigate the variations of the critical volume of consumed steel, critical expansive pressure and time to cover cracking. [ABSTRACT FROM AUTHOR]

Whole-rock major and trace elements, together with zircon U–Pb and Hf-isotope data, are reported for the granitic intrusions in the central part of the Jiamusi–Khanka Massif in the eastern segment of the Central Asian Orogenic Belt (CAOB), in order to investigate their precise geochronological framework, petrogenesis, sources and tectonic implications. LA-ICP-MS zircon U–Pb data, combined with previous ages, indicate that the Jiamusi–Khanka Massif is dominated by three stages of granitic magmatism, i.e., Cambrian (530–493 Ma), Permian (299–254 Ma) and Late Triassic (223–212 Ma), with two possible subordinate magmatic events that occurred in the Silurian (434–416 Ma) and Carboniferous (331–317 Ma). The Permian diorite and granodiorite contain high Al 2 O 3 (15.81–19.07 wt.%), Na 2 O (K 2 O/Na 2 O = 0.25–0.44) and Sr (748–949 ppm) contents and low Y (4–18 ppm) and Yb (0.37–1.94 ppm) contents, with high Sr/Y ratios of 54–207, indicating that they probably originated from partial melting of a mafic lower crust at high-pressure conditions. However, the coeval monzogranite and granite porphyry have higher SiO 2 , Y, Yb and HREE contents and lower Al 2 O 3 , Na 2 O/K 2 O ratio and Sr contents, together with the features of LILE-enriched, HFSE-depleted and Nb–Ta–Ti troughs, reflecting that they were likely produced by partial melting of arc-type crustal materials at a relatively shallow crustal level. Meanwhile, the Late Triassic granites contain high SiO 2 (75.90–77.40 wt.%) and K 2 O (4.17–4.87 wt.%), combined with low Sr and high Y and HREE, suggesting that they were possibly generated from crustal materials with involvement of slab-derived fluids at low pressure. All the granitoids have high 176 Hf/ 177 Hf ratios (0.282518–0.282842) with Hf two-stage model ages of 2005–809 Ma, and most of the magmatic zircons have positive ε Hf (t) values, indicating that the primary magmas of these rocks were derived from partial melting of a dominantly “old” source with a possible significant addition of juvenile materials. Based on the geochemical data and the regional geological investigations, we propose that the Jiamusi–Khanka Massif was an exotic block probably derived from Gondwana, which might be located in a relatively southerly place compared with the current position and faced the Paleo-Pacific Ocean during the Early Permian–Late Triassic time. The Permian granitoids would form in an active continental margin setting, whereas the Late Triassic granites were most likely generated within a local extensional environment, both of which were closely related to the westward subduction of the Farallon plate of the Paleo-Pacific Ocean beneath the Jiamusi–Khanka Massif. [ABSTRACT FROM AUTHOR]

Social network types have been proved to have significant impacts on older population's health outcomes. However, the existing discoveries are still inconsistent, which may be attributed largely to the heterogeneous measures and methods scholars used and to the unidirectional causalities presumed in most research. This study addresses these gaps by using more-refined measures to explore whether the network types have differential impacts on older adults' health outcomes, and whether a reverse causal relationship exists between older adults' health conditions and the network types they adopted. Using data from three recent waves (2005, 2008, and 2012) of the Chinese Longitudinal Healthy Longevity Survey (n = 4190), we constructed four network types using the K-means clustering method (i.e., diverse, friend, family, and restricted), and examined their impacts on a variety of health outcomes (i.e., physical, cognitive, psychological, and overall well-being). Our results demonstrate that there are strong reciprocal associations between these two factors. On the one hand, a diverse network type yielded the most beneficial health outcomes as measured by multiple health indicators, and the friend-focused network type is more beneficial than the family-focused network type in physical outcomes but not in psychological outcomes. On the other hand, we found that a decrease in all health indicators leads to withdrawal from more-beneficial network types such as a diversified network type, and a shift to less-beneficial network types such as family-focused or restricted networks. The understanding of this reciprocal association could encourage programs designed to enhance healthy aging to focus on improving the bridging social capital of older adults so that they can break the vicious cycle between network isolation and poor health conditions. [ABSTRACT FROM AUTHOR]

Summary Public–private partnership (PPP) has gained popularity during the market-oriented reforms in China’s urban infrastructure sectors. This paper explores how city characteristics, spatial pressures, and other institutional forces condition the extent of liberalization reforms in local infrastructure markets. The findings advance the policy diffusion literature by suggesting that the different diffusion mechanisms not only function independently, but also moderate each other’s effects under certain conditions. Specifically, this research finds that the effects of peer pressure undermine the effects of spatial exposure, and the influence of provincial government reduces the effectiveness of peer pressure and epistemic influences. [ABSTRACT FROM AUTHOR]

Abstract: A 5-bit lumped CMOS step attenuator with low insertion loss and low phase distortion is designed and simulated in this paper. The proposed attenuator is based on lumped switched bridged-T and π structure attenuators, and implemented with 0.18-μm CMOS technology. Different attenuation states are controlled by NMOS switches. The switches in series branches have channel-shunt resistance to minimize the on-resistance without increasing parasitic capacitance. The NMOS switches in shunt branches are body-floated to improve the power handling performance of the proposed attenuator. Each attenuation module has an inductive phase-compensate low-pass network. The attenuator is controlled with a 5-bit digital signal to achieve the maximum attenuation amplitude range of 0–31dB with 1dB increase at 3–22GHz. The root mean square (RMS) amplitude errors for each one of the 32 states are less than 0.53dB and the RMS insertion phase is less than 6.3° at 3–22GHz. The insertion loss is 5.5–13dB, and the input P1dB is 18.4dBm at 12.5GHz. [Copyright &y& Elsevier]