Perancangan Sistem Value Chain Terhadap Prospek Pengumpulan E-Waste Di Bank Sampah

Electronic waste (e-waste) has become environmental issue in Indonesia. Several tons of e-waste was generated each year. Available landfills will not be sufficient to accommodate e-waste that people produce. Waste bank become one of many solutions to overcome this problem. Implementation of pilot project in waste bank is needed to see the prospects of e-waste collection in waste bank. Thus, the goal of this research is to design a value chain system for e-waste collection prospect in waste bank and system simulation as the foundation for implementing a pilot project. Simulations on 2 scenarios had been done to determine profitability of e-waste collection's pilot project in waste bank. Based on simulation, it is known that there is profit generated from e-waste recycling process for 2 scenarios. Ranges of profit for 2 months are Rp. 7.963.879 - Rp. 40.447.047 for scenario 1 and Rp. 7.952.394 – 40.435.561 for scenario 2. If only PCB component that could be recycled, profit for 2 months still can be generated in the range Rp. 689.964 – Rp. 6.398.486 for scenario 1 and Rp. 678.478 – Rp. 6.387.000 for scenario 2. Thus, implementation of e-waste collection's pilot project in waste bank is profitable

Magnetism and electron spin resonance in single crystalline beta-AgNpO2(SeO3)

We report magnetization, susceptibility, electrical transport, and electron spin resonance (ESR) studies of single crystals of beta-AgNpO2(SeO3). Here the valence of the Np sites is expected to be Np(V). We observe a magnetic transition below 8 K, where the transition temperature is dependent on the effective magnetic moment. Although the transition appears to be ferromagnetic, no hysteresis is seen in the magnetization, and the saturation moment above 0.1 T is found to be about 60% of the free NpO2 ion moment. The decrease in the Np moments determined experimentally is thought to arise from crystal field and spin-orbit effects. Although Np(V) is expected to be ESR silent, we observe temperature dependent ESR spectra at ~44 GHz (for fields above the saturation field) that show slight shifts in the g-factor and line width at low temperatures. Our results provide evidence that both Np(V) and Np(IV) valences are present, where the latter may be a minority population. The crystals, although dark in appearance, are electrically insulating (rho > 10^10 Ohm-cm) at room temperature.Comment: 6 pages, 8 figure

High field magnetic resonant properties of beta'-(ET)2SF5CF2SO3

A systematic electron spin resonance (ESR) investigation of the low temperature regime for the (ET)2SF5CF2SO3 system was performed in the frequency range of ~200-700 GHz, using backward wave oscillator sources, and at fields up to 25 T. Newly acquired access to the high frequency and fields shows experimental ESR results in agreement with the nuclear magnetic resonance (NMR) investigation, revealing evidence that the transition seen at 20 K is not of conventional spin-Peierls order. A significant change of the spin resonance spectrum in beta'-(ET)2SF5CF2SO3 at low temperatures, indicates a transition into a three-dimensional-antiferromagnetic (3D AFM) phase.Comment: 4 pages, 7 figures, minor grammatical change

Semiconductive and Photoconductive Properties of the Single Molecule Magnets Mn12_{12}-Acetate and Fe8_8Br8_8

Resistivity measurements are reported for single crystals of Mn$_{12}$-Acetate and Fe$_8$Br$_8$. Both materials exhibit a semiconductor-like, thermally activated behavior over the 200-300 K range. The activation energy, $E_a$, obtained for Mn$_{12}$-Acetate was 0.37 $\pm$ 0.05 eV, which is to be contrasted with the value of 0.55 eV deduced from the earlier reported absorption edge measurements and the range of 0.3-1 eV from intramolecular density of states calculations, assuming $2E_a$= $E_g$, the optical band gap. For Fe$_8$Br$_8$, $E_a$ was measured as 0.73 $\pm$ 0.1 eV, and is discussed in light of the available approximate band structure calculations. Some plausible pathways are indicated based on the crystal structures of both lattices. For Mn$_{12}$-Acetate, we also measured photoconductivity in the visible range; the conductivity increased by a factor of about eight on increasing the photon energy from 632.8 nm (red) to 488 nm (blue). X-ray irradiation increased the resistivity, but $E_a$ was insensitive to exposure.Comment: 7 pages, 8 figure

Muon spin rotation study of the intercalated graphite superconductor CaC6 at low temperatures

Muon spin rotation (muSR) experiments were performed on the intercalated graphite CaC6 in the normal and superconducting state down to 20 mK. In addition, AC magnetization measurements were carried out resulting in an anisotropic upper critical field Hc2, from which the coherence lengths xi_ab(0)=36.3(1.5) nm and xi_c(0)=4.3(7) nm were estimated. The anisotropy parameter gamma_H= H_c2_ab/H_c2_c increases monotonically with decreasing temperature. A single isotropic s-wave description of superconductivity cannot account for this behaviour. From magnetic field dependent muSR experiments the absolute value of the in-plane magnetic penetretion depth lambda_ab=78(3) nm was determined. The temperature dependence of the superfluid density rho_s(T) is slightly better described by a two-gap than a single-gap model