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Due to rapid expansion in the global economy and industrialization, PM2.5 (particles smaller than 2.5 µm in aerodynamic diameter) pollution has become a key environmental issue. The public health and social development directly affected by high PM2.5 levels. In this paper, ambient PM2.5 concentrations along with meteorological data are forecasted using time series models, including random forest (RF), prophet forecasting model (PFM) and autoregressive integrated moving average (ARIMA) in Anhui province, China. The results indicate that the RF model outperformed the PFM and ARIMA in the prediction of PM2.5 concentrations, with cross-validation coefficients of determination R2, RMSE and MAE values of 0.80, 11.50 µg/m3 and 8.13 µg/m3, respectively. PFM achieved the average results (R2 = 0.73, RMSE = 13.21 µg/m3 and MAE = 9.17 µg/m3), while the predicted results by ARIMA are comparatively poorer (R2 = 0.63, RMSE = 15.56 µg/m3 and MAE = 10.64 µg/m3) than RF and PFM. These findings reveal that the RF model is the most effective method for predicting PM2.5 and can be applied to other regions for new findings.

The novel coronavirus (COVID-19), first identified at the end of December 2019, has significant impacts on all aspects of human society. In this study, we aimed to assess the ambient air quality patterns associated to the COVID-19 outbreak in the Yangtze River Delta (YRD) region using a random forest (RF) model. To estimate the accuracy of the model, the cross-validation (CV), determination coefficient R

To study the damage evolution laws of red sandstone samples with prefabricated cracks under cyclic uniaxial compression, physical tests were conducted. In this research, the stress–strain curve characteristics, failure process characteristics, strength, and deformation properties of the cracked sandstone specimens were studied under different cracked geometric parameters (α, β) and cyclic loads. The experimental results revealed that the elasticity modulus, deformation modulus, residual strength, and peak strength increased linearly with the number of loading cycles. Additionally, the failure modes of the samples transition from brittle failure under a small number of loading cycles to ductile failure under a high number of loading cycles. The elastic modulus and peak strength of all the specimens under cyclic loading showed a “strengthening” phenomenon. With increasing crack dip angle (α), the peak strength and crack initiation stress first increased and then decreased. However, with the increase in the crack bridge inclination angle (β), the peak strength and crack initiation stress first decreased and then increased. By using the fitting analysis of the damage evolution equation, it was proven that the damage variable method is suitable for describing the damage evolution characteristics of cracked sandstone.

Plastics are man-made long-chain high polymeric compounds which have long-lasting effects on environment and human health. One of the most concerning issues of plastic is related with their associated chemicals and their subsequent effects upon release on ecological resources and human beings. The current study was conducted with the purpose to assess the composition of solid waste generation in general and plastic waste generation in particular. The study further examines the potentials of plastic waste refinery in district Peshawar (Pakistan) with its cost management and possible potentials to reduce the greenhouse gas emissions. Average per capita waste generation for Peshawar City was found to be 0.46 kg/cap/day, while the physical composition of municipal solid waste (MSW) intimated that food waste is the major component generated with an average of 0.257 kg/cap/day (52% of the total MSW) followed by plastic waste as the second major component with an average of 0.077 kg/cap/day (16%). The total volume of plastic waste was found to be 330 tons/day in the study area. It has been estimated that the establishment of plastic waste refinery for 330 tons of plastic waste can save an amount of 66,725,340 rupees/annum along with generation of 551/month mgwt energy and reduction of 41.08 GHGT/year greenhouse gases emission. The findings of this study will be helpful for the concerned departments and decision-makers for establishment of plastic waste refineries for sustainable plastic waste management.

Rock cliff faces are mostly avoided in rock engineering research, especially where the scale of the slope exceeds the scale of fracturing present in the rock mass. The research to understand the rock cliff face joints plays an important role in slope engineering. This paper presents a rock block identification method based on unnamed aerial vehicle photogrammetry and its computer implementation of Cliff face rock, Fort Munro Pakistan. An advance bundle adjustment method was used to build the real three-dimensional (3D) surface model of the rock mass. Later, random sample consensus algorithm was used to search the structural planes in cloud point model. A computer program, geotechnical structure and model analysis (GeoSMA-3D) was developed to solve the engineering problems and to verify the example. The program confirmed the efficiency of the theory in dealing with complex surface modelling and cliff face rocky slope stability analysis. The approach presented can be applied as a general guiding design principle for cliff face rock slope.

In current research, a novel geometrical technique is introduced to estimate the length (L) of sliding arc by considering slip surface entry point distance (de). Morgenstern-Price limiting equilibrium and strength reduction methods are selected within the framework of SLOPE/W and FLAC3D softwares respectively, to study the sliding mechanism and stability-effecting factor for a loose rock slope comprise of two different material. Also, the variability influence of strength parameters (cohesion force and friction angle) and the depth of pore water pressure on safety factor, failure depth (D) and distribution range of critical failure surface (CFS) are investigated through software. The results show that the shear strength parameters and the depth of pore water pressure plays a significant role in altering overall stability and the distribution range of CFS for a loose rock slope. Shallow failure with composite failure surface is much easier to occur for loose rock slope subjected to pore water pressure and material heterogeneity. These findings can be effectively used for loose rock slope reinforcement design.

In loose or highly weathered rock slopes, the circular shear failure mechanism occurs in large scale. Most rock slope stability investigations ignore the influence of geometric parameters, i.e., failure surface entry point distance (le). This study presents failure surface determination based on constant element stress-based method. The failure surfaces and their sliding mechanism are analyzed first by using FLAC3D (Fast Lagrangian Analysis of Continua in three-dimension). A real case of instability corresponds to a loose rock is presented and its stability is determined by numerical analysis. To investigate the effectiveness of present method the influence of shear strength (c, φ) and geometric parameters (α, β) on the safety factor (FS) is also analyzed by using Geo5, FLAC3D and ABAQUS computer codes. Then, Geo5 and Statistical Package for the Social Sciences (SPSS) softwares were used to determine the effect of dimensionless parameter lambda (λ) on the failure surface entry point distance (le) and length of failure arc (L). The results show that shear failure may occur in non-homogeneous slope. Shear failure has exit and entry points situated either on the surface or near the toe of slope. The length of failure arc (L) is affected by the le and λ. Moreover, it can be acknowledged that the relation of both L and le with shear strength parameters (c, φ) is logarithmic, respectively. So, based on the rock strength parameters, L and le are predictable by using the equations derived from non-linear regression.

The analysis of damage process and the characterization of damaged rock masses through numerical models are the most difficult and challenging tasks in geotechnical engineering. This review paper describes and collects information regarding the causes of damage in the rocks and damage models (constitutive and hybrid damage models) for rock damage analysis. The main objective of this review is to discuss the causes of damage process, characterization, constitutive modes, and impact of natural changes on the selection of damage model. The review suggests that releasable strain energy, crack propagation and coalescence, joints, natural changes, and engineering disturbance are the main causes of rock fracture and damage. Most studies showed that a wider range of rock mass characterization will be required to create an ideal numerical model due to the rock reality, inelasticity, fractures, anisotropy, and inhomogeneity. Hybrid models are more efficient computationally as compared with the constitutive models. The review concludes that numerical models are also applicable tools to understand damage scale, damage degree and type, damage location, and damage occurrence time in the rocks.

Block failure is a common type of uncertainty in blocky and layered rock slopes. One of the most critical types of block failure is a slide of slope top flexural toppling. In the current research, such kind of block failure is studied through numerical modeling. For this purpose, extensive field investigations and laboratory tests were conducted to determine the structural geology and strength parameters. Block theory was used within the network of geotechnical structure and model analysis (GeoSMA-3D) tool to identify the key sliding blocks. Strength reduction method (SRM) was selected in finite difference computer program FLAC3D to examine the failure mechanism of whole cut slope. The volume of sliding blocks, block sliding faces, horizontal displacement, and corresponding safety factor (FS) were evaluated by using software. The results indicated that cut slope is unstable and partial block-flexural failure can occur at the upper part of the slope. The results suggested that the deformation of upper layers of cut slope was more as compared with that of the lower layers. The findings of the present study can be used to take operative safety treatment of the layered cut slope in Pakistan.

This study investigates PCBs attenuation and the abundance of active polychlorinated-degrading Dehalococcoides spp. biphenyl dioxygenase (bphC), chemotaxis (CheA), and flagellum (flic) genes in floody and dry soil conditions polluted with polychlorinated biphenyls. The results revealed that total PCBs, high chlorinated PCBs (>4 cl), and less chlorinated PCBs (

Pharmaceuticals (VPs) are used in large amounts to protect human health and reduce diseases and promote growth for livestock and poultry in farms. Due to their use pattern, they possess a potential for reaching the soil environment where they develop resistance and can impact the soil ecosystem services. The environmental pollution and health risks caused by the antibiotics and antibiotic resistance genes (ARGs) have become urgent issues all over the world. This chapter provides a comprehensive overview of the occurence of antibiotics and ARGs in soil. The fate of antibiotics such as photodegradation, bioremediation, chemical treatments, etc., was discussed in detail. ARGs’ occurrence and their mechanism (horizontal and vertical) of transfer into soil ecosystem were reviewed. We review the impact that pollution by antibiotics or by antibiotic resistance genes may have for both human health and the evolution of environmental microbial populations. The chapter could be helpful to university teachers, students, and management authorities for the management and to develop the policy for the new emerging environmental contaminates.

Heavy metal concentrations in sediments of the Kurang stream: a principal feeding tributary of the Rawal Lake Reservoir were investigated using enrichment factor (EF), geoaccumulation index (Igeo) and metal pollution index (MPI) to determine metal accumulation, distribution and its pollution status. Sediment samples were collected from twenty one sites during two year monitoring in pre- and post-monsoon seasons (2007-2008). Heavy metal toxicity risk was assessed using Sediment Quality Guidelines (SQGs), effect range low/effect range median values (ERL/ERM), and threshold effect level/probable effect level (TEL/PEL). Greater mean concentrations of Ni, Mn and Pb were recorded in post-monsoon season whereas metal accumulation pattern in pre-monsoon season followed the order: Zn>Mn>Ni>Cr>Co>Cd>Pb>Cu>Li. Enrichment factor (EF) and geoaccumulation (Igeo) values showed that sediments were loaded with Cd, Zn, Ni and Mn. Comparison with uncontaminated background values showed higher concentrations of Cd, Zn and Ni than respective average shale values. Concentrations of Ni and Zn were above ERL values; however, Ni concentration exceeded the ERM values. Sediment contamination was attributed to anthropogenic and natural processes. The results can be used for effective management of fresh water hilly streams of Pakistan.