Taking the black soil of northeastern cold land as the research object, this paper adopts the three-factor quadratic saturation D311 optimal design scheme, uses static black box-gas chromatography to analyse the irrigation season, nitrogen fertilizer and straw biochar to the impact of greenhouse gas emissions for N2O growing season in the northeast cold paddy field. This paper also studies the optimal water and fertilizer application scheme for N2O control. The results show that the effects of three factors on N2O emissions are as follows: nitrogen fertilizer > biochar > water. The irrigation and biochar have an inhibitory effect on N2O emissions, while nitrogen fertilizer has a promoting effect on N2O emissions. The performance is as follows: water + nitrogen fertilizer can promote the emission of N2O; water + biochar can inhibit the emission of N2O; nitrogen fertilizer + biochar can promote the emission of N2O. Combined with the yield, the integrated water and biochar optimization schemes, when controlling the increase of N2O growth season in paddy fields to not exceed 10% are as follows: The amount of irrigation is 4252~5531 kg/hm2; the nitrogen application rate is 103.30~117.35 kg/hm2; and the amount of biochar is 15.12~24.42 t/hm2.

The radioactive field is one of the most important areas in human health. It must be studied to see the changes in the doses of human exposure. In this study, 46 soil samples were collected from different locations of Karakh side at Baghdad Governorate. The specific activity of natural radionuclides (terrestrial gamma radiation) 238U, 232Th and 40K for soil samples were measured using gamma-ray spectroscopy with NaI(Tl) ("3×3") detector in low-background. Moreover, ten radiological hazard parameters, which include radium equivalent activity (Raeq), absorbed gamma dose rate (Dγ), external hazard index (Hext), internal hazard index (Hint), representative gamma index (Iγr), annual effective dose equivalent (AEDE) that includes the indoor and outdoor effective dose rate, and ELCR were calculated. It has also used GIS technology for mapping specific activity and radiological radiation parameters for all the samples under study. The results show that, the average value of specific activity of terrestrial gamma radiation 238U, 232Th, 40K, 238U+232Th+40K and 235U were 16.47±0.94 Bq/ kg, 9.72±0.43 Bq/kg, 367.95±11.13 Bq/kg, 394.15±11.90 Bq/kg and 0.76±0.043 Bq/kg respectively. While, the average value of radiological radiation parameters such as Raeq, Hex, Hin, Iγr , Iα, Exposure, Dr, AGED, AEDEindoor, AEDEoutdoor, AEDEtotal, and ELCR in present study were 58.7183±2.017 Bq/kg, 0.1586±0.00546, 0.2032±0.00768, 0.4523±0.0151, 0.08237±0.0046, 3.367±0.113 μR/h, 28.8309±0.968 nGy/h, 207.1078±6.86 mSv/y, 0.1415±0.00475 mSv/y, 0.03541±0.00119 mSv/y, 0.177±0.00594 mSv/y and 0.6192 ±0.0208 respectively. The results indicate that the effective dose from terrestrial gamma radiation is everywhere across the area within the acceptable level, subject to the inherent spatial averaging of the measurements.

Toxic and harmful gases, noise, industrial dust, loads, and job posture in architectural engineering construction are the different factors that influence health loss of construction workers. Among them, construction dust is a primary occupational health threat among construction workers. Accordingly, this study aims to analyze the dust pollution hazard in the architectural construction process and quantitatively estimate the health loss of construction workers. It uses a case study based on an earthwork stage in a construction site at Zhengzhou City, Henan Province, China. Environmental health risks were evaluated by using the exposure parameter method, while estimating the health losses of different objects caused by earthwork in this construction site. Results demonstrated that dust in the earthwork site was caused by the cement process and moving vehicles. Cementers and road cleaners suffered the most threats from dust with dust exposure dosages of 0.48 and 0.21 mg/kg·d, respectively. The health losses of cementers and road cleaners reached CNY 19,342.74 and CNY 14,532.36, respectively. A reduction on health costs caused by dust pollution in architectural engineering construction is possible through the following proposed measures: strengthening the monitoring of the construction workers’ level of exposure to dust pollution, establishing a health management system for construction workers, focusing on the effect of environmental supervision mechanism, and standardizing the emission standards of construction dust pollution. Results could provide some references in understanding the current status and distribution law of dust pollution in construction sites, promoting the implementation of health management and protection system for construction workers, enhancing the working environment of construction workers, and quantitatively estimating the total health influences of architectural engineering.

Riparian zones suffer from increased human disturbances and the plant communities change unpredictably in response to altered conditions. It is important to understand the effects of human activities on plant communities for rational tourism development and ecological protection programs. We sampled 14 and 27 sites in nearly natural and human-influenced landscapes along the Lijiang River in southwest China, respectively, to detect human impacts on the ecosystem. We set three survey lines, based on a submersion gradient, at each site to determine whether herbaceous species richness increased with distance from the river, and we examined the effects of disturbance on herbaceous distribution. The landscapes shared 101 common species, and unique species in the human-influenced landscape were partly synanthropic. The species richness and diversity indices of the nearly natural landscape were significantly higher than those of the human-influenced landscape (P < 0.01). Species richness increased with distance from the river in the nearly natural landscape, and a significant difference was detected among the variances of survey lines (P < 0.05) in the human-influenced landscape. In the nearly natural landscape, species richness increased with fewer hydrological effects, and a stable community was maintained. However, human disturbances led to community variability and fragmented riparian habitats, resulting in species extinction and ecological degradation. We suggest that appropriate dam and reservoir regulations, prohibition of soil destructions, and a long-term research program for ecosystem protection may help in improving the monitoring of human influences and sustainable management in riparian zones of tourist rivers.

The modelling of chlorophyll-a concentration helps to restrict the harmful effects in marine species caused by increased nutrient loads. The derived satellite data are often used for the monitoring of marine ecology. The common usage of satellite data is monthly average data to avoid the problem of missing values. In order to reduce the effect of missing data, this study employed the cubic spline model by using a satellite data for investigating seasonal variations of chlorophyll-a mapped in an eight-day interval consisting of missing values in Pattani Bay, Thailand from the year 2003 to 2017. This study further used the spline-fitted data for creating the baseline model of chlorophyll-a in Pattani Bay, and for examining the difference between spline fitted and monthly average data. This study revealed that the cubic spline method was able to handle the missing values in satellite data to gain the smoothness in data. When both models were compared, the spline-fitted observation yielded a smoother curve pattern than the monthly average observation. The spline fitted model was also able to display the chlorophyll-a data at any particular day of the year. It was also shown that the chlorophyll-a concentration level in the coastal area of Pattani Bay was higher in the inshore pixels, especially in rainy season.

Catechol and hydroquinone are widely applied in industrial synthesis while they are typical toxic organic pollutants. Efficient adsorptive removal of catechol and hydroquinone is highly needed. In this research, activated carbon fibre (ACF) was used for the kinetic removal of the two pollutants. As catechol and hydroquinone have different pKa values, it was found that the highest uptake of catechol and hydroquinone was observed at pH 11.0 and 5.0, respectively. The adsorption kinetics for catechol and hydroquinone were compared. The removal of hydroquinone is higher than that of catechol at almost all the pH conditions. At pH 7.0, the uptake of catechol and hydroquinone on ACF were 125.8 and 200.4 mg/g, respectively. As both Elovich and pseudo-second-order kinetic models could better describe the adsorption process, the adsorption of catechol and hydroquinone onto ACF might be chemisorption. The rate determining step might be diffusive in nature for the uptake of catechol and hydroquinone. Linear pseudo-second-order kinetic model fitted the experimental data better than pseudo-first-order kinetic model. The presence of natural organic matter, humic acid, could inhibit the uptake of catechol and hydroquinone on ACF profoundly.

Waste lubricant oil can be regenerated by flocculation and adsorption to get rid of impurities. In this work, the performance of flocculants (chitosan, sodium carbonate and sodium silicate) and sorbents (carclazyte and silica gel) were evaluated experimentally. The results showed that the combination of chitosan and sodium carbonate had beat results in removal of acid value and mechanical impurities. Silica gel contacting adsorption had the best colour removal. Thermal precipitation (80°C, 24h) was adopted as primary step before flocculation to wipe off heavier particulate matter. The best ratio of chitosan, sodium carbonate and silica gel was 1:1:1, and the best dosage of chitosan was 2% compared to oil. After the re-refining process, viscosity decreased from 186.34 (mm2/s, 40°C) to 155.21 (mm2/s, 40°C), the acid value from 0.26 (mg KOH/g) to 0.06 (mg KOH/g), mechanical impurities content from 3.62% to 1.41%, water content from 0.45% to 0.06%, and light absorbance from 4.31 to 1.17.

Hybrid membranes are currently being developed to find the membrane that is having good chemical and thermal resistance. This research devotes to the development of hybrid membrane from clay/TiO2 with PVA polymer and its application for colour wastewater filtration. The results show that the optimum concentration of PVA is 5%. At this condition, the hybrid membrane has a bulk density of 2 g/cc and porosity of 23.13%. The hybrid membrane produces the coefficient rejection of 79.48%. At the higher concentration of PVA, the filtration becomes not effective because the flux of membrane is very low.

A graphene-based magnetic composite (Fe3O4/GO) was prepared and used for simultaneous removal of Cu(II) and 1-naphthol. The composite was characterized by SEM, TEM, XRD, FT-IR and Raman. Electron microscopy reflected that Fe3O4 spheres were dispersed on graphene layers. The pseudo-second-order kinetic and Langmuir isotherm models could best describe the sorption kinetics and isotherms. The sorption of Cu(II) and 1-naphthol increased with increasing temperature, and thermodynamic parameters calculated from temperature dependent sorption revealed that sorption of Cu(II) and 1-naphthol on Fe3O4/GO was spontaneous and endothermic. The results indicated that Fe3O4/GO can be utilized as potential adsorbents for purification of co-contaminated water systems.

Crown profile models are key components of growth and yield models and are crucial for estimating the crown volume and constructing 3D visualization of trees. We used a total of 431 trees collected from 98 pure even-aged temporary sample plots established in Fujian Province to develop crown profile models of Chinese fir (Cunninghamia lanceolata).To describe the shape of tree crowns more accurately, significance tests of the effects of different stand conditions (stand age, site index, and stand density) on crown shape were conducted with one-way analysis of variance (ANOVA). Multiple comparisons based on the ANOVA results were used to classify the crown data into three groups according to stand age: Group I (young forest), Group II (medium forest), and Group III (nearly mature and mature forest). We analysed the relationships between the crown variables and stand variables and used the reparameterization approach to develop three optimal crown profile models for different age groups. Stand variables (such as stand density) further improved the prediction efficacy of the models. Considering the correlation between repeated measurement data for the same tree crown, the non-linear mixed-effects modelling (NLME) method was used to account for autocorrelation. The determination coefficients (R2) of the above three optimal models fitted by the non-linear mixed-effects approach were 0.9214, 0.9398 and 0.9129, and their Root Mean Squared Errors (RMSEs) were 0.1246, 0.1409 and 0.1786, respectively. The determinant coefficients (R2) of the three models fitted by the nonlinear least squares (NLS) approach were 0.9015, 0.8794 and 0.8930, and their RMSEs were 0.1395, 0.2102 and 0.1878, respectively. The results indicated that the predicted accuracy was significantly increased by using non-linear mixed effects modelling compared with the NLS method.