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"ABSTRAKPada penelitian ini dilaporkan investigasi mengenai efek dari eksposur faset kristal (001) TiO2 anatase terhadap aktivitas fotoelektrokatalitik dari fotoanoda yang terdiri dari film nanokomposit BiVO4/TiO2. Fotoanoda dibuat dengan mendeposisikan nanokomposit di atas permukaan kaca FTO melalui teknik doctor blade. Dalam penelitian ini, empat jenis morfologi TiO2 antase yaitu, nanospindel, nanocube, nanooctahedral, dan nanosheet disintesis melalui metode hidrotermal dengan penambahan directing agent yang berbeda. Selanjutnya, TiO2 hasil sintesis dikarakterisasi dengan menggunakan X-Ray Diffractometer (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmelt Tellers (BET), dan UV-Vis diffuse reflectance spectra (DRS). Berdasarkan hasil karakterisasi, puncak difraksi menunjukkan karakteristik untuk fase anatase murni dengan eksposure faset kristal (001) untuk nanospindel dan nanocube dan faset kristal (101) untuk nanocube dan nanooctahedral. Selain itu, respon fotoelektrokimia dari fotoanoda juga diukur menggunakan sistem 3 elektroda pada reaktor photocatalytic fuel cell (PFC) dan menghasilkan nilai densitas arus mencapai 0,0386 mA/cm2 untuk nanokomposit BiVO4/TiO2 nanosheet dan 0,0381 mA/cm2 untuk nanokomposit BiVO4/TiO2 nanospindle. Menggunakan sistem PFC ini, degradasi rhodamin B yang diperoleh adalah sebesar 23,15% untuk nanokomposit BiVO4/TiO2 nanosheet dan 30,58% untuk nanokomposit BiVO4/TiO2 nanospindle selama 3 jam reaksi.

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ABSTRACTThis work reports an investigation on the effect of exposing (001) crystal facet of anatase TiO2 to photoelectrocatalytic activity of photoanode composed of TiO2/BiVO4 nanocomposite film. Here, the photoanode was fabricated by depositing the nanocomposite on the surface of FTO via doctor blade technique. In this study, four different types of anatase TiO2 morphologies, i. e. nanospindle, nanocube, nanooctahedra, and nanosheet were synthesized via hydrothermal method in the presence of various directing agents. Furthermore, the as-prepared TiO2 was characterized using X-Ray Diffractometer (XRD), Transmission Electron Microscopy (TEM), Brunauer-Emmelt-Tellers (BET), and UV-Vis diffuse reflectance spectra (DRS). Based on the result, the diffraction peaks revealed characteristic for the pure anatase phase with exposure (001) crystal facet for nanospindle and nanosheet and (101) crystal facet for nanocube and nanooctahedra. Additionally, photoelectrochemical response of the photoanode was also evaluated using a three-electrode system on the photocatalytic fuel cell (PFC) reactor and exhibited a significantly high current density value of 0.0386 mA/cm2 and 0.0381 mA/cm2 for TiO2 nanosheet/BiVO4 and TiO2 nanospindle/BiVO4 nanocomposite. Using this PFC system, the degradation of rhodamine B were obtained 23.15% and 30.58% for TiO2 nanosheet/BiVO4 and TiO2 nanospindle/BiVO4 nanocomposite for 3 hours reaction time. "

"Studi komputasi adalah studi yang ditentukan dari perhitungan struktur elektronik berupa material, seperti Fe, Ni, dan Co. Struktur kristal berupa material Fe, Ni, dan Co yang dikomputasikan adalah Fe3Ni2 dan Fe6Ni3Co. Struktur Fe6Ni3Co yang didapatkan dengan mengganti Ni pada Fe3Ni2 dengan Co. Studi ini telah dilakukan dengan menggunakan Density Functional Theory (DFT) melalui metode atomistik, optimasi geometri, dan analisis konstanta elastis. Metode atomistik menunjukkan bahwa struktur kristal yang berbentuk tetragonal dan kelompok ruang P4/mmm. Optimasi geometri dilakukan dengan menggunakan energy cutoff sebesar 300 eV terhadap struktur kristal yang berbentuk tetragonal dengan parameter kisi (a, b, c) adalah (10, 10, 1) dalam satuan Å. Analisis konstanta elastis menghasilkan besaran Cij terdiri dari i adalah pola regangan secara masing-masing sebanyak 6 dan j adalah amplitudo sebanyak 6. Cij berguna untuk menentukan konstanta elastis beserta jenisnya, antara lain modulus elastisitas, modulus bulk, modulus geser, kompresibilitas, dan rasio poisson serta berguna untuk menentukan kondisi stabilitas dari Fe3Ni2 dan Fe6Ni3Co.

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Computational studies are studies that are determined from the calculation of the electronic structure of materials, such as Fe, Ni, and Co. The crystal structures in the form of Fe, Ni, and Co materials which are computed are Fe3Ni2 and Fe6Ni3Co. The Fe6Ni3Co structure obtained by replacing Ni in Fe3Ni2 with Co. This study was carried out using Density Functional Theory (DFT) through atomistic method, geometry optimization, and elastic constant analysis. Atomistic method shows that the crystal structure is tetragonal and the space group is P4/mmm. Geometry optimization was carried out using a cutoff energy of 300 eV for a tetragonal crystal structure with lattice parameters (a, b, c) of (10, 10, 1) in Å units. Analysis of the elastic constant produces the amount Cij consist of i is the pattern of strain as many as 6 each and j is the amplitude of 6. Cij is useful for determine the elastic constants and their types, including modulus of elasticity, bulk modulus, shear modulus, compressibility, and poisson’s ratio as well useful to determine the stability conditions of Fe3Ni2 and Fe6Ni3Co."

"PT Nabisco Foods is a food industry which is facing quality problem, that is product overweight. Overweight percentage existing reaches 5,44 percent meanwhile company?s maximum taret for overweight is only 3 percent. Six Sigma is a comprehensive methodology for quality improvement which is directly eliminating the main special sources of problem with DMAIC (De_firie-MeaszIre-Analyze-improve-Coniro/) approach. Six Sigma concept is aimed to increase process capability, reduce variation between outputs and adjust them with the target.Determining product O with Reguler type as the main focuss, research scope is limited in mixing, forming dan baking area. Then the actual process capability is evaluated by measuring weight and thickness parameter of base cake. For weight parameter, level sigma is 5,04 dan 99,93 percent yield. These metric value indicates that the process capability for weight parameter is quite good. On the other hand, for thickness parameter, level sigma 3,45 and 97,42 percent yield are received which points that improvement focuss on process related to thickness parameter is needed. By analyzing actual process, the root causes with highest risk level are identiiied, one of them is the leak of correlation of temperature between oven zone. The outcome of using Taguchi method is the optimum setting that are I baking time in 6 menit, suhu zone 1,2 dan 3 subsequently 500, 610 and 650 F.For the last phase of Six Sigma., author recommend utilization of control chart form for monitoring process capability continuously with thickness of base cake as the parameter."

"Summary:Using the simplifications made possible by the availability of computer technology, this is a solid state physics text for physics students. It emphasises on physics rather than formal mathematics. It attempts to add important developments in the field without sacrificing the book's accessibility and teachability"