Platinum-group metals (PGM) are important precious metals in many industrial fields. However, their natural resource deposits are strictly limited. Accordingly, their recycling process from wastes and/or secondary resources must be considered. In this study, the leaching of PGM from automotive catalyst residue was performed based on the formation of their chloro-complexes in various concentration of acidic solution. The recovery of platinum, palladium and rhodium from the samples after hydrogen reduction pretreatments was examined in the leaching process by using a mild solution mixture of NaClO-HCl and H 2 O 2 at 65 C for 3 h. Effect of other solution mixtures on the extraction of the precious metals was also compared with NaClO-HCl-H 2 O 2 , such as HCl-H 2 O 2 and NaClO-HCl. The optimum condition to dissolve platinum, palladium and rhodium was achieved by the mixture of 3 vol% NaClO, 5 kmolÁm À3 HCl and addition of 1 vol% H 2 O 2 . The recovery of platinum, palladium and rhodium after 3 h leaching reaches 88%, 99%, 77%, respectively.

Tujuan penelitian ini yaitu untuk menganalisis pengaruh sosialisasi perpajakan terhadap kepatuhan wajib pajak orang pribadi dengan kesadaran wajib pajak orang pribadi sebagai variabel mediasi. Populasi pada penelitian ini adalah Wajib Pajak Orang Pribadi yang telah terdaftar di Kantor Pelayanan Pajak Pratama Semarang Tengah Dua yang berjumlah 10.661 wajib pajak. Perhitungan jumlah sampel menggunakan rumus slovin, sampel yang digunakan dalam penelitian ini adalah sebanyak 100 kuesioner yang disebarkan langsung di KPP Pratama Semarang Tengah Dua atas izin pejabat yang berwenang dalam KPP tersebut. Analisis data menggunakan pendekatan Partial Least Square (PLS) dengan menggunakan program WarpPLS 4.0. Hasil penelitian menunjukkan bahwa variabel sosialisasi perpajakan dapat mempengaruhi kesadaran wajib pajak sebesar 50,4% dan sosialisasi perpajakan, dan kesadaran wajib pajak dapat mempengaruhi kepatuhan wajib pajak sebesar 58,5%. Hasil penelitian menunjukkan bahwa sosialisasi perpajakan berpengaruh positif terhadap kesadaran wajib pajak orang pribadi, sosialisasi perpajakan berpengaruh positif terhadap kepatuhan wajib pajak orang pribadi, kesadaran wajib pajak berpengaruh positif terhadap kepatuhan wajib pajak orang pribadi, serta kesadaran wajib pajak memediasi pengaruh sosialisasi perpajakan terhadap kepatuhan wajib pajak orang pribadi.Kata kunci : Sosialisasi Perpajakan; Kesadaran Wajib Pajak Orang Pribadi; Kepatuhan Wajib Pajak Orang Pribadi

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Recycling platinum group metals (PGMs) from waste and/or secondary resources is becoming quite important due to the limitation of the natural resource deposits of PGMs. Among the processes of PGMs' recycling from secondary resources, the hydrometallurgical method draws extensive concerns, particularly for the selection of leaching solution. The present work evaluated the ability of chloride leaching solutions, i.e. HCl-H 2 O 2 and NaClO-HCl-H 2 O 2 to extract Pt, Pd and Rh from a kinetic point of view. The effect of temperature in the range of 277-307 K and time were also examined under the conditions of À500 mm of particle size and 100 g L À1 of pulp density.The kinetic model (I):was found to be the most suitable to describe the leaching process of Pt, Pd and Rh in the NaClO contained solution. In this model the interface transfer and diffusion across the leached support layer both affect the rate of leaching reaction.fits the kinetic data very well for the dissolution of Pd in the HCl-H 2 O 2 solution, showing that the diffusion across the leached support layer mainly affect the kinetic behaviors and the diffusion coefficient is inversely proportional to leaching time t. The NaClO contained solution and HCl-H 2 O 2 solution leaching of Pt, Pd and Rh are strongly dependent on the leaching temperature. In the case of the NaClO contained solution, the activation energy based on model (I) for Pd, Pt and Rh was 63.5, 59.1 and 77.9 kJ mol À1 , respectively. It is probably because of that the diffusion of NaClO contained solution across the leached support layer was very slow due to the micro-porous structure of the catalyst; and a high activation energy was needed in effect. Regarding to the leaching in the HCl-H 2 O 2 solution, the activation energy for Pd was 13.4 kJ mol À1 on the basis of model (II).

A new b Ti alloy was designed and fabricated by powder metallurgy process using pure metallic powders. The addition of Mo and Cr increased the stability of the b phase. By contrast, O promoted a phase formation upon cooling. The addition of 18%Mo and 10%Cr stabilized the b phase into ambient temperature. O increased the critical cooling rate of formation of a phase due to the prediction of the continuous cooling transformation diagram calculated by the Java-based Material Properties software. Sintering and solution treatment also enhanced the alloying behavior of pure powders to their designated chemical compositions. Hardness of the alloy decreased with increasing Mo and Cr content, which led to the decrease of a phase. The Ti-18%Mo-10%Cr alloy exhibited better corrosion resistance than a commercial Ti-6%Al-4%V alloy, which is used as current biomaterial.