Investigating the Effect of Replacing Domestic Water Meters in Reducing the Apparent Losses, Case Study (Region 3 of Water and Wastewater Company of Isfahan Province)

Performance accuracy of water meters have a special effect on apparent losses and non-revenue water. The purpose of this paper is investigating the effect of replacing faulty water meters on income generation of water and wastewater companies & encouraging them to replace water meters. 198 water meters from 2 old subscription zones from region 3 of Isfahan were chosen as a sample & replaced in summer 2020. The average monthly consumption one period after replacement was compared with the similar monthly period in last year/years. The results were validated with the results of laboratory test of a number of old water meters of different brands. 35% of water meters had increase in consumption, 13% had decrease in consumption and the average of mean monthly consumption has increased to 26.55%. water meters with the brands 4 had the most negative error. Replacement of water meters reduce the low consumption class and increase the high consumption and misuse class which causes the increase of %67.83 in water rate. The results were generalized to 5928 subscribes of region 3 with over 20 years old water meters. Payback period for replacing all old water meters with the size of 0.5 and 0.75 inch was 4.3 years

Thermal Properties of the Binary-Filler Composites with Few-Layer Graphene and Copper Nanoparticles

The thermal properties of an epoxy-based binary composites comprised of graphene and copper nanoparticles are reported. It is found that the "synergistic" filler effect, revealed as a strong enhancement of the thermal conductivity of composites with the size-dissimilar fillers, has a well-defined filler loading threshold. The thermal conductivity of composites with a moderate graphene concentration of ~15 wt% exhibits an abrupt increase as the loading of copper nanoparticles approaches ~40 wt%, followed by saturation. The effect is attributed to intercalation of spherical copper nanoparticles between the large graphene flakes, resulting in formation of the highly thermally conductive percolation network. In contrast, in composites with a high graphene concentration, ~40 wt%, the thermal conductivity increases linearly with addition of copper nanoparticles. The electrical percolation is observed at low graphene loading, less than 7 wt.%, owing to the large aspect ratio of graphene. At all concentrations of the fillers, below and above the electrical percolation threshold, the thermal transport is dominated by phonons. The obtained results shed light on the interaction between graphene fillers and copper nanoparticles in the composites and demonstrate potential of such hybrid epoxy composites for practical applications in thermal interface materials and adhesives.Comment: 25 pages, 4 figure

Graphene Composites as Efficient Electromagnetic Absorbers in the Extremely High Frequency Band

We report on the synthesis of the epoxy-based composites with graphene fillers and testing their electromagnetic shielding efficiency by the quasi-optic free-space method in the extremely high frequency (EHF) band (220 - 325 GHz). The curing adhesive composites were produced by a scalable technique with a mixture of single-layer and few-layer graphene layers of a few-micron lateral dimensions. It was found that the electromagnetic transmission, T, is low even at small concentrations of graphene fillers: T<1% at frequency of 300 GHz for a composite with only 1 wt% of graphene. The main shielding mechanism in composites with the low graphene loading is absorption. The composites of 1 mm thickness and graphene loading of 8 wt% provide excellent electromagnetic shielding of 70 dB in the sub-terahertz EHF frequency with negligible energy reflection to the environment. The developed lightweight adhesive composites with graphene fillers can be used as electromagnetic absorbers in the high-frequency microwave radio relays, microwave remote sensors, millimeter wave scanners, and wireless local area networks.Comment: 28 pages, 6 figure

Phonon and Thermal Properties of Quasi-Two-Dimensional FePS3 and MnPS3 Antiferromagnetic Semiconductor Materials

We report results of investigation of the phonon and thermal properties of the exfoliated films of layered single crystals of antiferromagnetic FePS3 and MnPS3 semiconductors. The Raman spectroscopy was conducted using three different excitation lasers with the wavelengths of 325 nm (UV), 488 nm (blue), and 633 nm (red). The resonant UV-Raman spectroscopy reveals new spectral features, which are not detectable via visible Raman light scattering. The thermal conductivity of FePS3 and MnPS3 thin films was measured by two different techniques: the steady-state Raman optothermal and transient time-resolved magneto-optical Kerr effect. The Raman optothermal measurements provided the orientation-average thermal conductivity of FePS3 to be 1.35 W/mK at room temperature. The transient measurements revealed that the through-plane and in-plane thermal conductivity of FePS3 is 0.85 W/mK and 2.7 W/mK, respectively. The films of MnPS3 have higher thermal conductivity of 1.1 W/mK through-plane and 6.3 W/mK in-plane. The data obtained by both techniques reveal strong thermal anisotropy of the films and the dominant contribution of phonons to heat conduction. Our results are important for the proposed applications of the antiferromagnetic semiconductor thin films in spintronic devices.Comment: 43 pages, 8 figure