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This article describes a wideband filter-less radio frequency (RF) power amplifier (PA) with in-band harmonics suppression using a polyphase network. The novel passive polyphase (three-way three-phase) network helps in suppressing both the second and third harmonics of the PA present within the operating band. The architecture uses three extended continuous class F (CCF) PAs, which are combined using the proposed polyphase network. The output power of the overall system varies between 41.7 and 42.4 dBm from 0.65 to 2.05 GHz. The second and third harmonic suppression levels are improved by 15–28 and 12–15 dB, respectively, when compared with that of the standalone PA.

Groundwater is one of the major sources of water in arid and semi-arid regions. Hence, its qualitative assessment and knowledge about spatial variations are important for the purposes of planning and management in agricultural and domestic consumption. In this study we applied the Normalized Difference Dispersal Index (NDDI) and the Normalized Difference Index (NDI) over pre- and post-monsoon data set for Dwarka city of Delhi, India. NDDI maps for five environmentally sensitive ions were generated by integrated geochemical analysis in the Geographical Analysis System (GIS). NDDI plots highlights spot specific enrichment (accretion or attrition and dilution) in the study area. The NDI values suggest that World Health Organization (WHO) standards are a little more stringent as compared to Bureau of Indian Standards (BIS).

Remediation of wastewater, sludge and removal of objectionable substances from our environment using radiation technology is neglected. Hardly, a couple of decades ago, application of electron beam (EB) technology has gained attention for waste management. When wastewater is irradiated with electron beam, the beam can alter the physico-chemical properties of irradiated aqueous material and also transform wastewater chemicals due to the excitation or ionization of chemical molecules. Thus, chemical reactions may be capable of producing new compounds. The beam of electrons initiates primary reactions to induce the excitation or ionization of molecules at varied rates. This review paper will help to a budding researcher how to optimize the irradiation process to achieve high efficiency with low electron beam energy which is economically viable/feasible. Application of E-beam radiation for wastewater treatment may ensure future smart cities with sustainable water resources management.

AbstractIn this study, geo-statistical tool was used to map groundwater quality parameters. Groundwater samples were collected from 30 wells. In order to quantify the site-specific variations, Normalized Difference Dispersal Index (NDDI) was used to map five parameters namely pH, EC, TH, Ca, and Mg. Maximum NDDI value enrichment was exhibited by EC (−0.01) and Mg (−0.009 ≈ −0.01) it reflects accretion. In addition, for pH (−0.012), TH (−0.027), and Ca (−0.025), it outlined by dilution or minor accretion, whereas median NDDI value for EC, Ca, Mg, TH and pH is −0.02, −0.02, −0.03, −0.029, and −0.04, respectively. NDDI mapping is a functional tool for evaluation and comparative assessment of spatio-temporal variations in groundwater. Further, frequency distribution and inter correlation analysis of the data-set has displayed coherence. The results of study will help in management of water resources.

The efficacy of electron beam radiation for the disinfection and reduction of organic load of sewage water was assessed with ILU-6 Accelerator at Radiation Technology Development Division of the Bhabha Atomic Research Centre, Mumbai India. The current problem on environmental health in relation to water pollution insists for the safe disposal of sewage water. In general, sewage water comprises heterogeneous organic based chemicals as well as pathogens. EB treatment of the wastewater has found to be very effective in reducing the pathogens as well as organic load. EB dose of 1.5 kGy was sufficient for complete elimination of total coli forms. The experimental results elucidated the reduction of biological oxygen demand—BOD (35 and 51.7%) in both inlet and outlet sewage samples. Similarly reduction of chemical oxygen demand—COD was observed (37.54 and 52.32%) in both sewage samples with respect to increase in irradiation doses (0.45–6 kGy). The present study demonstrated the potential of ionizing radiation for disinfection of sewage and to increase the water quality of the wastewater by decreasing BOD and COD. So, the irradiation sewage water can find its application either in agriculture for irrigation, in industry for cooling purpose and some selected domestic purposes.

In the last decade, phase changing material slurry (PCMS) gained much attention as a cooling medium due to its high energy storage capacity and transportability. However the flow of PCM slurry is a complex phenomenon as it affected by various parameters, i.e. fluid properties, velocity, particle size and concentration etc.. In the present work ice is used as a PCM and numerical investigation of heterogeneous slurry flow has been carried out using Eulerian KTGF model in a horizontal pipe. Firstly the present model is validated with existing experiment results available in the literature, and then model is applied to the present problem. Results show that, flow is almost homogeneous for ethanol based ice slurry with particle diameter of 0.1 mm at the velocity of 1 m/s. It is also found that ice particle distribution is more uniform at higher velocity, concentration of ice and ethanol in slurry. Results also show that ice concentration increases on the top of the pipe, and the effect of particle wall collision is more significant at higher particle diameter.