Peste des petits ruminants (PPR) is a highly contagious disease of small ruminants. The purpose of this study was to investigate the epidemic characteristics of PPR outbreaks in the People's Republic ...of China (PR China) from 2013 to 2018. A total of 41,876 PPR outbreaks were recorded in small ruminant populations in PR China during that period. Data from February to June 2018 were used to study new developments in the PPR epidemic in PR China. Spatio‐temporal clusters and temporal distribution patterns were studied based on PPR notifications. We also used multiple logistic regression to examine the contribution of anthropogenic, climatic and topographic factors to PPR outbreaks. Distance to the nearest road (OR = 1.007 95% CI: 1.001–1.014), price of mutton (OR = 1.904 95% CI: 1.358–2.668) and mean monthly temperature in July (OR 1.156 = 95% CI: 1.110–1.204) showed positive effects on PPR outbreaks. Negative effects were observed for number of large‐scale farms (OR = 0.962 95% CI: 0.940–0.985). We also found that observed patterns of seasonality were characterized by peaks in April of 2014. Spatio‐temporal clusters occurred in Yunnan, Jiangsu, Anhui, Heilongjiang province and Chongqing municipality. Hunan province reported PPR occurrences every year from 2014 to June 2018. Yunnan, Jiangsu and Anhui province have 56, 33 and 30 epidemic locations, respectively. PPR infections were first reported as the cause of death for 19 wild bharals in Qinghai province in 2018. All of this suggests that domestic trading of sheep and goats may be closely related to the spread of PPR. Prophylactic immunization in suspected animal populations or areas is recommended for the control of PPR and wild small ruminants should be monitored. Results presented here provide improved knowledge about PPR dynamics in PR China, which could be helpful in designing more effective prevention strategies.
Basic oxygen furnace slag (SS) is prone to carbonation due to its alkaline properties. The combined use of carbonated basic oxygen furnace slag (CSS) with metakaolin (MK) as a composite supplementary ...cementitious material (CSS-MK) can improve the reactivity of CSS and significantly lower the overall embodied CO2 emission. However, the impact of CSS-MK on the resistance of external sulfate attack (ESA) of cement remains unclear. This study aims to clarify the influence of CSS-MK on the resistance of cement to ESA. Compressive strength, water absorption, and electrical flux before ESA, and macro-scale expansion, microstructure, and evolution of phase assemblage during ESA were investigated. Results indicate that CSS-MK exhibits higher strength reactivity compared to SS-MK, enabling a 30% cement replacement level without compromising compressive strength after 7 days. CSS-MK reduces water absorption by 37.9% and electrical flux by 67.6%, enhancing transport property and reducing sulfate ion intrusion into the cement paste. The carbonation treatment transforms calcium silicate in SS into CaCO3, decreasing soluble calcium content, and creating a CaCO3-based passivation layer that inhibits sulfate ion corrosion. Meanwhile, the reaction in CSS-MK blends between the CaCO3 in CSS and MK consumes Ca(OH)2, forms ettringite and thermodynamically more stable carboaluminate, and results in the absence of monosulfate prior to ESA and the presence of carboaluminate during ESA, which consequently decreases ettringite content by 40% in paste after 240 days of ESA. Furthermore, at the macroscopic level, the expansion decreased by 85.2% after 360 days of ESA, effectively mitigating specimen cracking and damage.
•The combined substitution of carbonated steel slag and metakaolin enhances resistance to external sulfate attack (ESA).•The reaction between carbonated steel slag and metakaolin reduces the permeability and ettringite formation during ESA.•The presence of a CaCO3-based passivation layer decreases soluble Ca content and impedes the leaching of Ca from steel slag.
The microstructure of a 3D-printed mortar was investigated in present study. To enhance the density contrast between sand and cementitious slurry, a novel leaching strategy was used as an auxiliary ...method, based on which the spatial dispersion of sands in 3D-printed mortar was rendered. Meanwhile, to alleviate the problem of CT's limited resolution, X-ray attenuation method (XRAM) was introduced in this study to investigate the spatial distribution of local porosity in 3D-printed mortar. Besides, focusing on single filaments, the upper part of the filaments presented lower sand rate and higher porosity than the lower part, and the difference between the filaments located near the top of 3D-printed mortar was more significant. Finally, based on the sliding method, the interlayer width, average porosity and average sand ratio of 3D-printed mortar were estimated as 640
21.9% and 43.1%, respectively. The research results would deepen the understanding of 3D-printed concrete.
The steam curing technology is worldwide applied in the production of concrete prefabricated components, including the production of track slab and girder used for the high‐speed railway in China. ...However, the steam curing process at elevated temperature will often generate the heat damage on concrete and thus degrade the long‐term performance of the steam‐cured concrete prefabricated components. It is very important to deeply understand the mechanism of heat damage and thus to find effective method reducing or avoiding the damage of steam curing on concrete. The main purpose of this paper is to systematically classify the types of thermal damages on concrete during the steam curing and its mechanism. The influences of main factors on three thermal damages such as the unrecoverable expansion deformation, the surface layer defect, and the embrittlement of the steam‐cured concrete are discussed in detail. The controlling methods of thermal damages including optimization of the steam curing regime and mixing proportions, the addition of supplementary additives, the self‐healing technology, and other curing technology are compared and summarized based on the literatures. Finally, suggestions for future research are proposed in order to effectively reduce or even avoid the thermal damage of the steam‐cured concrete. And also, some new technology for developing the green and high performance early strength concrete with low CO2 emission are presented.
To solve the problems of poor thermal insulation and heat preservation properties that exist in the walls made of small-size concrete hollow blocks, a new type of compound small-size concrete hollow ...blocks has been developed. As shown in tests and calculations, the compound blocks not only improve significantly the thermal insulation effect, heat preservation properties, and impermeability of the walls, but also show good decorative results.
Chytridiomycosis, a leading cause for the global decline in the number of amphibians, is caused by the fungal pathogen
Batrachochytrium dendrobatidis
. In this study, global distribution data of
B. ...dendrobatidis
were collected from January 2009 to May 2019. Space–time scan statistics and the maximum entropy (MaxEnt) model were used to analyze the epidemic trends and aggregation of the pathogen, and predict
B. dendrobatidis
distribution through its relationships with climate factors, wind speed, and solar radiation. The results of space–time scan statistics show seven clusters of data for the distribution of
B. dendrobatidis
. The time was mainly concentrated in 2009, 2013, 2015, and 2016, and the regions were primarily concentrated in southeastern Canada, southwestern France, Nigeria, Cameroon, eastern Brazil, southeastern Brazil, central Madagascar, and central and eastern Australia. MaxEnt showed that annual precipitation had the largest contribution percentage in the model, and annual mean temperature highly influenced the distribution of
B. dendrobatidis
. The global high-risk areas of
B. dendrobatidis
distribution were mainly observed in western Canada, southern Brazil, Chile, the United Kingdom, Japan, the Republic of Korea, eastern South Africa, eastern Madagascar, southeastern Australia, and southern China.
► Colorimetric methods for measurement of chloride penetration. ► Factors affecting chloride concentration at the color change boundary. ► Methods for free chloride measurement. ► Measurement of ...chloride penetration depth. ► Applications measurement of AgNO
3colorimetric methods.
This paper reviews reaction mechanisms of AgNO
3, AgNO
3
+
K
2CrO
4 and AgNO
3
+
fluoresceine colorimetric methods, and their applications for measurement of chloride ion penetration in concrete. Among the three methods, AgNO
3 method is most widely applied because it gives similar results but simpler and faster than the other two methods. AgNO
3-based colorimetric methods can potentially measure two variables, chloride ion penetration depth and chloride concentration at the color change boundary. Reported chloride ion concentrations at the color change boundary (C
d
) measured or calculated by some researchers vary over a broad range due to many factors, such as sampling procedure, chloride ion analysis method, alkalinity of concrete, sprayed volume and concentration of AgNO
3 solution, pore solution volume and methods for measuring free chloride concentration in concrete, etc., in which sprayed volume and concentration of AgNO
3 solution are main factors. The smaller the volume of sprayed AgNO
3 solution with a certain concentration, the lower the
C
d
is. 0.1
mol/L AgNO
3 solution has most clear color of boundary. To obtain a lower C
d
, a proper sprayed volume of 0.1
mol/L AgNO
3 solution should be determined. However, this important point was not mentioned at all times since the AgNO
3 method was applied. Based on small range of
C
d
, AgNO
3 method can be a useful method for rapidly evaluating chloride ion penetration in reinforced concrete structures in chloride environments.
Cement-asphalt mortar interlayer plays an important role in ballast-less track in high speed railway. Cement-asphalt mortar undergoes repetitive changes in temperature when it is exposed to its ...service environment. Change in temperature has a significant effect on the thermal deformation of cement-asphalt mortar, and even affects directly the durability of ballast-less track. In the paper, length and mass of the specimens of cement-asphalt mortar were continuously measured during the heating and cooling cycles within the range of temperatures of -10~60degreesC. The results indicate that there is an evidently irreversible shrinkage at the end of the first cycle of heating and cooling. The shrinkage taken place at the end of cycles of heating and cooling decreases with the increase in cycle numbers. Apart from the curve for the first heating, deformation curves of cement-asphalt mortar either for heating or for cooling are nearly lines. After being heated and cooled for 5 times, the temperature-deformation curve for heating nearly overlaps the curve for cooling. The percent of moisture loss at the end of every cycle decreases with the increase in cycle numbers. Thermal shrinkage occurs at about 0degreesC in the first heating.
We investigate quantum state tomography（QST） for pure states and quantum process tomography（QPT） for unitary channels via adaptive measurements. For a quantum system with a d-dimensional Hilbert ...space, we first propose an adaptive protocol where only 2d. 1 measurement outcomes are used to accomplish the QST for all pure states. This idea is then extended to study QPT for unitary channels, where an adaptive unitary process tomography（AUPT） protocol of d2＋d.1measurement outcomes is constructed for any unitary channel. We experimentally implement the AUPT protocol in a 2-qubit nuclear magnetic resonance system. We examine the performance of the AUPT protocol when applied to Hadamard gate, T gate（/8 phase gate）, and controlled-NOT gate,respectively, as these gates form the universal gate set for quantum information processing purpose. As a comparison, standard QPT is also implemented for each gate. Our experimental results show that the AUPT protocol that reconstructing unitary channels via adaptive measurements significantly reduce the number of experiments required by standard QPT without considerable loss of fidelity.
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