•PET aggregate concrete has better workability compare to natural aggregate concrete.•Reduction of density is achievable with PET coarse aggregate in concrete.•Relatively high compressive strength is ...attainable with PET aggregate concrete.
This study investigates the effect of plastic as an alternative coarse aggregate on various fresh and harden properties of concrete. Polyethylene terephthalate (PET), a thermoplastic polymer, is considered as an alternative aggregate and replaced with natural coarse aggregate, such as brick chips. The PET aggregate is obtained by shredding, melting and crushing the collected waste PET bottles. The primary focus of the work is to observe compressive strength and unit weight of PET aggregate concrete (PAC) along with their workability in comparison with the natural aggregate concrete (NAC). With the increase in PET replacement ratio and w/c ratio lower unit weights and compressive strengths are observed for PAC compare to NAC. Compressive strength for 20% PET replaced PAC at 0.42w/c ratio is 30.3MPa which is only 9% less than the NAC. However, PAC has significantly high workability as 1.8cm slump value is observed for 20% PET replaced PAC at 0.42w/c ratio. Therefore, PET replaced concrete with low w/c ratio and high workability can be used for structural concrete member.
A wide range of human–robot collaborative applications in diverse domains, such as manufacturing, health care, the entertainment industry, and social interactions, require an autonomous robot to ...follow its human companion. Different working environments and applications pose diverse challenges by adding constraints on the choice of sensors, degree of autonomy, and dynamics of a person-following robot. Researchers have addressed these challenges in many ways and contributed to the development of a large body of literature. This paper provides a comprehensive overview of the literature by categorizing different aspects of person-following by autonomous robots. Also, the corresponding operational challenges are identified based on various design choices for ground, underwater, and aerial scenarios. In addition, state-of-the-art methods for perception, planning, control, and interaction are elaborately discussed and their applicability in varied operational scenarios is presented. Then some of the prominent methods are qualitatively compared, corresponding practicalities are illustrated, and their feasibility is analyzed for various use cases. Furthermore, several prospective application areas are identified, and open problems are highlighted for future research.
MAIN CONCLUSION : The enhanced expression of a P ₁B -type ATPase gene (SaHMA3) is essential for Cd hyperaccumulation and hypertolerance in Sedum alfredii Hance. A functional understanding of the ...mechanism through which hyperaccumulator plants accumulate and tolerate extremely toxic metals is a prerequisite for the development of novel strategies for improving phytoremediation using engineered plants or natural hyperaccumulators as well as biofortification and food crop safety. Most hyperaccumulator species, however, are small and slow-growing, and their potential for large-scale decontamination of polluted soils is limited. Sedum alfredii Hance, the only one metal hyperaccumulator from the Crassulaceae family, is an ideal candidate for gaining a functional understanding of the intra-family hyperaccumulation mechanisms as well as their potential applications. In the present study, we isolated and functionally characterized a P₁B-type ATPase gene (SaHMA3) from S. alfredii Hance. SaHMA3 alleles from a hyperaccumulating ecotype (HE) and non-hyperaccumulating ecotype (NHE) were constitutively expressed in both shoot and root and encoded tonoplast-localized proteins, but showed differences in transport substrate specificity and expression level. SaHMA3 h from the HE plant was a Cd transporter. In contrast, SaHMA3n from NHE plants was able to transport both Zn and Cd. SaHMA3 showed a significantly higher constitutive expression level in HE plants than in NHE plants. Furthermore, the expression level of SaHMA3 in the shoots of HE plants was considerably higher than in the roots. Overexpression of SaHMA3h in tobacco plants significantly enhanced Cd tolerance and accumulation and greatly increased the root sequestration of Cd. In summary, our data suggested that SaHMA3 plays critical roles in Cd hyperaccumulation and hypertolerance in Cd hyperaccumulator S. alfredii Hance.
Synthesis of iron oxide nanoparticles by the recently developed green approach is extremely promising because of its non-toxicity and environmentally friendly behavior. In this study, nano scaled ...iron oxide particles (α-Fe2O3) were synthesized from hexahydrate ferric chloride (FeCl3.6H2O) with the addition of papaya (Carica papaya) leaf extract under atmospheric conditions. The synthesis of iron oxide nanoparticles was confirmed by systematic characterization using FTIR, XRD, FESEM, EDX and TGA studies. The removal efficiency of remazol yellow RR dye with the synthesized iron oxide nanoparticles as a photocatalyst was determined along with emphasizing on the parameters of catalyst dosage, initial dye concentration and pH. Increasing the dose of iron oxide nanoparticles enhanced the decolorization of the dyes and a maximum 76.6% dye degradation was occurred at pH 2 after 6 h at a catalyst dose of 0.8 g/L. Unit removal capacity of the photocatalyst was found to be 340 mg/g at dye concentration of 70 ppm and at a catalyst dose of 0.4 g/L. The synthesized nanoparticles showed moderate antibacterial activity against Klebsiella spp., E.Coli, Pseudomonas spp., S.aureus bacterial strains. Although the cytotoxic effect of nanoparticles against Hela, BHK-21 and Vero cell line was found to be toxic at maximum doses but it can be considered for tumor cell damage because it showed excellent activity against the Hela and BHK-21 cell lines.
Materials science, Materials chemistry, Nanotechnology, Iron oxide nanoparticles, Carica papaya, Photocatalytic activity, Remazol yellow RR, Antibacterial activity, Cytotoxicity.
•Foliar application of Zn and Se promoted growth of water spinach.•Foliar fertilizers increased Zn and Se bioavailability in Caco-2 cell line.•Biofortification reduced Cd and Pb concentrations but ...not bioavailability.•Cytotoxicity of HL-7702 was bioavailable dose-dependent.•Nutrition quality improved by foliar application of Zn and Se fertilizers.
The present study investigated the effects of foliar application of zinc (Zn) and selenium (Se) on bioavailability of Zn and Se and toxicity of cadmium (Cd) and lead (Pb) to different water spinach ecotypes (LA and HA) grown in slightly (XZ) or moderately (LJY) contaminated fields via in vitro digestion combined with Caco-2/HL-7702 cell model. The obtained results revealed that foliar application of Zn and Se promoted yield, increased total, bioaccessible and bioavailable fractions of Zn and Se in plants, indicating that foliar application is a feasible way of biofortification. Although there was no significant effect on liver cell proliferation (MTT), membrane stability (LDH) and hepatocyte enzyme (ALT and AST) activities, the obvious ecotype and soil dependent fluctuations of lipid peroxidation (MDA) and antioxidant enzyme (SOD, POD and CAT) activities in serum highly suggest that the low accumulator and clean field should be used in agricultural production rather than the high accumulator and contaminated farmland. Moreover, foliar application of Zn and Se improved nutritional quality of all water spinach genotypes in both fields, including increased Fe, vitamin C, cellulose and chlorophyll, maintained concentrations of potassium (K), manganese (Mn), copper (Cu), protein, and nitrate. These results demonstrate that this agricultural management practice may prove to be an effective approach for minimizing health risk and alleviating “hidden hunger” in the developing countries.
A wireless sensor network (WSN) consists of specialized sensor nodes that perform sensing services for Internet of Things devices with limited battery power. As the replacement or recharging of ...batteries is not possible, energy consumption becomes the most important design issue in WSNs. The energy‐efficient routing protocol gets the most priority in such energy‐constrained networks. The utilization of clustering‐based routing protocols like stable election protocol (SEP) has gained much attention as the network's lifetime is significantly improved due to the clustering of sensor nodes. Moreover, the inclusion of a secondary CH (SCH) is beneficial when the member node with the most remaining energy performs data aggregation and reduces the energy burden of the CH. This article characterizes SEP and Prolong SEP (P‐SEP) protocols and then extends them by incorporating SCH, which ensures balanced energy consumption. The performance of the proposed Extended SEP and Extended P‐SEP protocols has been analysed regarding stability period, network lifetime, energy usage and throughput. The simulation results demonstrate that the proposed protocols outperform state‐of‐the‐art protocols like P‐SEP, Modified SEP (M‐SEP) and SEP. In particular, the stability period of Extended SEP and Extended P‐SEP has improved up to 42% and 89%, respectively, compared to M‐SEP.
Secondary cluster head (SCH)based two routing protocols, namely Extended stable election protocol (SEP) and Extended P‐SEP, have been proposed for heterogeneous wireless sensor networks. Hence, SCH reduces the energy burden of the CH as well as increases the lifetime of the network. The simulation results demonstrate that the proposed protocols outperform state‐of‐the‐art protocols like SEP and P‐SEP.
•Polypropylene aggregate (PPA) is used as a partial replacement of coarse aggregates, such as crushed stone and burnt clay brick aggregates to evaluate the properties of concrete.•Concrete with 30 % ...PPA shows a higher slump value and lower density than both the control stone aggregate concrete (SAC) as well as brick aggregate concrete (BAC).•For both the SAC and BAC, concrete containing 10 % PPA exhibits higher mechanical strength compared to the control as well as the other PPA content concrete.•The ultrasonic pulse velocity (UPV) for the concrete is a function of aggregate types and PPA content.•Based on multiple regression analysis, empirical equations are proposed to predict various strength properties from the compressive strength values and to evaluate compressive strength from the UPV values.
The application of waste materials in concrete is getting more popular in the concrete industries as it can reduce the associated costs and environmental impacts. The present study investigates the performances of concrete while incorporating polypropylene (PP) plastic, derived from waste plastic products, as a partial replacement of natural stone aggregate (SA) and burnt clay brick aggregate (BA). The main variables include the percentage of PP aggregate (PPA) (0%, 10 %, 20 %, and 30 %), water-cement ratio (0.45 and 0.55), and types of aggregate (SA and BA). Results are presented in terms of workability, hardened density, compressive, tensile strengths, modulus of rupture, modulus of elasticity (MoE), ultrasonic pulse velocity (UPV), and cost analysis. Furthermore, empirical equations are proposed for predicting different properties of concrete; especially, predicting compressive strengths from the UPV values. Results indicated that the slump value increased with increasing the percentage of PPA. Concrete with 10 % PPA exhibited higher compressive strength, modulus of rupture, and splitting tensile strengths, even, higher than that of the control stone aggregate concrete (SAC) and control brick aggregate concrete (BAC). The UPV values varied with aggregate types and PPA content. Both the compressive strength and the UPV values decreased with the increasing percentages of PPA from 10 to 30. Furthermore, SAC exhibited higher compressive strength and UPV values compared to BAC. A good correlation was found between the compressive strength and the UPV values for concrete with PPA. From the cost sensitivity analysis, it was observed that concrete containing 10 % PP content had the highest strength over cost ratio compared to the control and other PPA concrete. Therefore, it is recommended to use up to 10 % PPA either with stone aggregate or brick aggregate for structural concrete. Finally, this study will open new opportunities for producing green concrete by using non-biodegradable waste plastic materials.
Phytoremediation coupled with agro-production is a sustainable strategy for remediation of toxic metal contaminated farmlands without interrupting crop production. In this study, high accumulating ...oilseed rape was rotated with low accumulating rice to evaluate the effects of crop rotation on growth performance and uptake of cadmium (Cd) in plants. In this system, oilseed rape was inoculated with plant growth promoting endophyte (PGPE) consortium, and rice was applied with soil composite amendment and foliar inhibitor. The results showed, compared with rice monoculture, crop rotation coupled with superposition measure has potential to enhance yield, biomass and nutritional quality of both crops, as well as to increase Cd uptake in non-edible tissues of oilseed rape and to reduce Cd concentration in individual parts of rice, thus accelerating phytoextraction and ensuring food safety. These comprehensive management practices removed 7.03 and 7.91% total Cd from two experiment fields, respectively, in three years phytoremediation. These results demonstrated a feasible technical mode for phytoremediation coupled with argo-production in slightly Cd contaminated field, and also provided useful information for further investigation of interaction mechanisms between the rotated crops and biofortification measures.
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•Inoculation with PGPE consortium promoted growth and Cd uptake of oilseed rape.•Simple rotation with oilseed rape threatened food safety of succeeding rice.•Application of soil amendment and foliar inhibitor improved rice yield and quality.•Superposition biofortification measure exhibited utmost reduction in soil Cd.•Phytoremediation coupled with agro-production is a feasible technology.
Production of plastic has risen significantly in the last 60 years worldwide, and around 10% of this plastic is turned into solid waste. This plastic becomes an environmental hazard in the absence of ...appropriate recovery methods. Incorporating waste plastic in concrete is an alternate way to recycle this waste plastic. Polypropylene (PP) and polyethylene terephthalate (PET) are two of the most widely used plastic scarcely recovered and recycled. Therefore, in the present study, both PP and PET are used as a partial replacement (10%, 20%, and 30% by volume) of coarse aggregate. These concretes are compared for three different water-cement ratios (0.42, 0.48, and 0.57). Properties such as workability, density, compressive, and tensile strengths are compared. Concrete with PP aggregate has shown as much as 39% higher compressive strength and 9% lower density than brick aggregate concrete. On the other hand, concrete with PET aggregate has displayed as much as 53% reduction in compressive strength compared to the reference concrete. Furthermore, it demonstrates higher workability and lower density. Equations are proposed to describe relationships between compressive and splitting tensile strengths of concrete, including the effect of plastic aggregate percentages. Cost analysis of the concrete reveals that incorporating waste plastic in concrete is more expensive than the regular brick aggregate concrete. Still, up to 10%, PP can be used in concrete, considering the gain in compressive strength.
Cadmium (Cd) contamination and continuous cropping obstacle often coexist in greenhouse soil and seriously restrict cucumber production. In this study, hyperaccumulator Sedum alfredii Hance was ...intercropped with spring cucumber (Cucumis sativus L.), then rotated with low accumulator water spinach and autumn cucumber under rational water regime, composited amendment was applied to soil before transplanting autumn cucumber. The results showed that, compared with conventional crop rotation system (Chinese cabbage and cucumber rotation), superposition management practice suppressed Fusarium wilt disease by 28.4 and 57.4% and increased yield by 35.2 and 383% for spring and autumn cucumbers, respectively. Meanwhile, photosynthetic characteristics, antioxidant system and fruit quality were significantly improved. Furthermore, this mode modified soil microbial community structure, enhanced soil enzyme activities, and simultaneously reduced soil total and phytoavailable Cd by 30.3 and 47.7%, respectively. These results demonstrated a feasible technical system to achieve phytoremediation coupled with argo-production in Cd contaminated greenhouse soil with continuous cropping obstacle and provided useful information for further revelation of interaction mechanisms between multicropping and comprehensive biofortification measurements.
•Intercropping with S. alfredii was effective for suppressing cucumber wilt disease.•Water regime and soil amendment facilitated crops to achieve phytoavoidation.•Wilt disease inhibition was the cause of the phenotype and physiology improvement.•Superposition measure exhibited utmost modification of soil property.•Phytoremediation coupled with agro-production is a feasible technology.
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