Evidence of successful river spawning by lake trout (Salvelinus namaycush) in the Lower Niagara River,Lake Ontario

Restoration of a wild-produced lake trout Salvelinus namaycush population in Lake Ontario has not been successful despite the adult population often meeting or exceeding restoration targets. Lack of high-quality spawning habitat in Lake Ontario is suggested as one impediment to recruitment of wild lake trout, although the quantity and location of spawning habitat is poorly understood. If high-quality spawning habitat is limited in Lake Ontario, lake trout may be using uncommon spawning locations such as rivers. Anecdotal angler accounts point to the Niagara River as a lake trout spawning location. To better understand the potential of the Niagara River as a spawning location, egg and juvenile fish collections were conducted 12–14 river kilometers from the mouth of the Niagara River from 2010 to 2012; and mature female lake trout with surgically implanted acoustic tags were monitored from 2015 to 2019. Genetic analyses confirmed 60% of collected eggs and 93% of collected post-hatch juvenile fish in the Niagara River were lake trout. Tagged female lake trout returned to the Niagara River over consecutive years during the spawning season. The short duration of lake trout presence in the river (mean = 56 days/year) suggests female lake trout use the Niagara River primarily for spawning. Diversity in spawning locations may provide lake trout population’s resilience against environmental variability through a portfolio effect. Improved identification of riverine spawning locations, including their overall contribution to wild recruitment, may be a useful tool for managers to restore a wild-produced population of lake trout in Lake Ontario.     

Improving classification-based diagnosis of batch processes through data selection and appropriate pretreatment

This work considers the application of classification algorithms for data-driven fault diagnosis of batch processes. A novel data selection methodology is proposed which enables online classification of detected disturbances without requiring the estimation of unknown (future) process behavior, as is the case in previously reported approaches.The proposed method is benchmarked in two case studies using the Pensim process model of Birol et al. (2002) implemented in RAYMOND. Both a simple k Nearest Neighbors (k-NN) and complex Least Squares Support Vector Machine (LS-SVM) are employed for classification to demonstrate the generic nature of the proposed approach. In addition, the influence of different data pretreatment methods on the classification performance is discussed, together with a motivation for selecting the correct pretreatment steps. Finally, the influence of the number of available training batches is studied.The results demonstrate that a good classification performance can be achieved with the proposed data selection method even with a low number of faulty training batches by exploiting knowledge on the nature of the to-be-diagnosed faults in the data pretreatment. This provides a proof of concept for classification-based batch diagnosis and demonstrates the importance of incorporating process insight in the construction of data-driven process monitoring and diagnosis tools.     

Strong organic acid-assistant synthesis of holey graphitic carbon nitride for efficient visible light photocatalytic H2 generation

A facile and cost-effective method was developed for the synthesis of holey N-deficient graphitic carbon nitride nanosheets (FCN) using trifluoroacetic-acid-treated urea as a precursor. The role of trifluoroacetic acid on the composition, structure and photocatalytic performance of the prepared catalysts was carefully investigated. The obtained samples displayed laminated porous morphology with nitrogen defects, larger specific surface areas, extended range of spectral response and enhanced electron mobility of charge carriers. Consequently, the optimized catalyst FCN-400 exhibited superb photocatalytic performance and excellent cycling stability for hydrogen evolution. The hydrogen evolution rate over FCN-400 reached 309.3 μmol/h under visible light irradiation, which is 11.3-fold of that of urea-derived graphitic carbon nitride (27.3 μmol/h).     

Direct ink writing of cordierite ceramics with low thermal expansion coefficient

Since the application of cordierite ceramics is limited by the disadvantages of traditional preparation techniques, 3D printing technology provides the only choice for the rapid preparation of cordierite ceramics with highly complex structures. In this work, the fabrication of cordierite ceramics with complex structures was achieved by direct ink writing. The near-net-shape of cordierite ceramics was realized by the volume expansion caused by the phase transformation. A cordierite ceramic with an average shrinkage rate of 1.58 % was obtained at 1400 °C. The low shrinkage avoids design and manufacturing procedures carried out for dimensional and alignment errors. In addition, the coefficient of thermal expansion was as low as 1.69 × 10^?6 °C^?1. The effect of configuration on the thermal behavior of cordierite ceramics is understood by analyzing the phase composition and microstructure. The cordierites ink reported in this work offers additional possibilities for the production of novel complex structures.     

Fouling tendency of ash resulting from burning mixtures of biofuels. Part 1: Deposition rates

Specified mixtures of peat with bark and peat with straw were burned in a lab-scale entrained flow reactor that simulates conditions in the superheater region of a conventional biomass-fired boiler. The deposition rates were recorded on an air-cooled probe that was inserted into the reactor at the outlet. For both mixtures, the deposition behaviour followed a non-linear pattern, which suggests that physico-chemical interaction between the types of ash has taken place. Peat seems to act as a cleansing agent in all mixtures with straw, while it acts as a cleansing agent in mixtures with bark only up to a share of 50 wt% bark. Between 50 and 100 wt% bark, it seems that peat adds to the deposition. The results indicate that it is possible to burn up to 30 wt% bark (renewable biofuel and pulp mill waste) and up to 70 wt% straw (renewable biofuel and agricultural waste) in mixtures with peat (CO₂-neutral fossil fuel) without encountering increased deposition rates.     

建筑系统性能的案例分析

在能源问题日益突出的当今,建筑系统性能的分析十分必要。本文对某高层建筑及其改造方案进行了性能的综合分析。首先,对建筑的全年能耗及自然采光进行了分析;其次,研究了设计计算方法对设备系统容量的影响以及不同气候条件如何选取适合的被动式技术。通过案例分析发现,利用被动式技术,全年供暖热需求可以降低28.3%;改变建筑设计手法充分利用自然资源,照明能耗可以降低44.04%;另外,线传热系数法和面积加权法计算墙体平均传热系数时相对误差达到11.07%。     

Net-zero energy building schools

In the Netherlands with respect to sustainable educational building the main focus has been on energy saving. Recently some schools were built as rather environmental friendly schools with more attention to comfort and health aspects. The first NZEB designed school is analyzed and the results compared with other more traditional schools. With all the enthusiasm for NZEB buildings it is good to look into the pro and contra. In the past important necessary technological and organizational changes were frustrated and thus delayed as people only focused on the positive aspects and forgot about the possible negative aspects. This then resulted in disappointing pilot projects. Therefore the article will give a list of advantages and disadvantages and will come up with recommendations to gain more and lose less in the process of doing so. The way to approach the design task is to look for win–win situations, find those solutions which increases the advantages of NZEB while at the same time improve some of the NZEB disadvantages characteristics.     

基于燃池的新型灶连炕系统的实验研究

通过对北方农村地区供暖方式的调查,在以火炕为主要供暖方式的既有农宅基础上提出了一种基于燃池的新型灶连炕系统。该新型灶连炕系统的创新点在于将小型燃池放入灶下部,利用燃池阴燃的原理改善了夜间炕面温度下降速度快的问题。针对该系统进行不同工况下的热源特性分析,并将其与传统炕在炕面温度、炕面温度标准差、炕体蓄放热特性、炕体散热能力方面进行对比分析。结果表明燃池实际阴燃燃烧过程中出现逆向阴燃,这与燃池内部空气量的多少有关;该新型系统能有效维持夜间炕面温度处于人体热舒适范围内,采用阴燃后可使炕面温度分布更加均匀,炕面所提供的散热量有78.1%满足房间热负荷,避免了人们夜间重新填料,为该系统的推广应用提供依据。     

Renewables portfolio standard and regional energy structure optimisation in China

Eastern Coastal areas of China have been developing rapidly since the implementation of reforms and the opening of China's economic markets in 1978. As in most areas of the world, this rapid economic growth has been accompanied by large increases in energy consumption. China's coal-dominated energy structure has resulted in serious ecological and environmental problems. Exploiting renewable energy resources and introducing Renewables Portfolio Standard (RPS) are some of the most important approaches towards optimising and sustaining the energy structure of China. This paper discusses international experiences in the implementation of RPS policies and prospects for using these policies to encourage renewable energy development in China, establishes a concise definition of renewable resources, differentiating between the broad definition (which includes hydro over 25 MW in size) from the narrow definition (which limits the eligibility of hydro to below 25 MW in size), and quantitatively analyses the potential renewable energy target. The research shows that: (1) Under the narrow hydro definition the renewable energy target would be 5.1% and under the broad hydro definition it would be 18.4%. (2) Western China has contributed 90.2% of the total renewable electricity generation in the country (if big and medium hydropowers are not included). Including big and medium hydropower, the figure is 63.8%. (3) Eastern electricity companies can achieve their quota by buying Tradable Renewable Energy Certificates (TRCs or Green Certificates) and by exploiting renewable energy resources in Western China. The successful implementation of the RPS policy will achieve the goal of sharing the benefits and responsibilities of energy production between the different regions of China.     

Wheat straw and peat for fuel pellets—organic compounds from combustion

Wood pellets are an environmentally friendly biofuel with no net contribution to global warming. Today, the demand for wood pellets for residential heating is rapidly increasing in Sweden and many other countries. Therefore, alternative raw materials for pellet production, such as wheat straw and peat, are of great interest.Before these new fuels are widely used, it is important to study the emissions to air during combustion. The smoke contains a large number of compounds which, to varying degrees, can affect health and the environment. Specific organic compounds from five sequential combustion stages; initial smouldering, early flaming, late flaming, after-flame smouldering and final glowing, were determined for incomplete combustion of straw and peat/wood pellets on a laboratory scale and compared to those from softwood pellets.The emissions from incomplete combustion reflect the chemical composition of the fuel. During initial smouldering of the studied fuels, methoxyphenols from the lignin of the fuels were released at high concentrations. Relatively high concentrations of 1,6-anhydroglucose and furan-related compounds, originating from the polysaccharides of the fuel, were also found during this stage, especially in peat/wood pellet smoke. During flaming burning, wood pellets burned more efficiently and with even lower emissions than the other fuels. After-flame smouldering of the studied pellets, especially straw pellets, released high concentrations of compounds that are hazardous to health and the environment.