Analisis Pengaruh Suhu Mesin terhadap Emisi Gas Buang pada Kondisi Torsi dan Daya Maksimum Studi Kasus: Sepeda Motor Yamaha Vega Zr

Reaksi pembakaran bahan bakar bensin (C8H18) dengan oksigen (O2) dalam keadaan sempurna akan menghasilkan karbondioksida (CO2) dan uap air (H2O) murni. Tetapi karena bensin merupakan campuran senyawa hidrokarbon yang diikuti oleh unsur-unsur lainnya sedemikian rupa dalam proses pembakaran yang begitu singkat akan terjadi hasil unsur dan senyawa lainnya. Pada pengujian emisi gas buang biasanya yang dideteksi adalah senyawa dari unsur C, H dan N. Unsur Nitrogen perlu diamati karena merupakan kandungan udara terbesar yang melebihi Oksigen. Pada penelitian ini akan dilakukan pengamatan terhadap emisi gas buang pada kondisi torsi maksimum dan daya maksimum dengan memvariasikan suhu (temperatur) mesin. Senyawa yang diamati konsentrasinya adalah CO, CO2, HC dan O2. Torsi maksimum terjadi pada putaran rendah sedang daya masimum terjadi pada putaran yang lebih tinggi. Hasil percobaan memperlihatkan konsentrasi gas buang naik dengan naiknya temperatur, kecuali konsentrasi CO2. Konsentrasi CO dan HC lebih tinggi pada kondisi Torsi maksimum, sebaliknya untuk konsentrasi CO2 dan O2

B-Cyclin/CDKs Regulate Mitotic Spindle Assembly by Phosphorylating Kinesins-5 in Budding Yeast

Although it has been known for many years that B-cyclin/CDK complexes regulate the assembly of the mitotic spindle and entry into mitosis, the full complement of relevant CDK targets has not been identified. It has previously been shown in a variety of model systems that B-type cyclin/CDK complexes, kinesin-5 motors, and the SCFCdc4 ubiquitin ligase are required for the separation of spindle poles and assembly of a bipolar spindle. It has been suggested that, in budding yeast, B-type cyclin/CDK (Clb/Cdc28) complexes promote spindle pole separation by inhibiting the degradation of the kinesins-5 Kip1 and Cin8 by the anaphase-promoting complex (APCCdh1). We have determined, however, that the Kip1 and Cin8 proteins are present at wild-type levels in the absence of Clb/Cdc28 kinase activity. Here, we show that Kip1 and Cin8 are in vitro targets of Clb2/Cdc28 and that the mutation of conserved CDK phosphorylation sites on Kip1 inhibits spindle pole separation without affecting the protein's in vivo localization or abundance. Mass spectrometry analysis confirms that two CDK sites in the tail domain of Kip1 are phosphorylated in vivo. In addition, we have determined that Sic1, a Clb/Cdc28-specific inhibitor, is the SCFCdc4 target that inhibits spindle pole separation in cells lacking functional Cdc4. Based on these findings, we propose that Clb/Cdc28 drives spindle pole separation by direct phosphorylation of kinesin-5 motors

Search for light top squark pair production in final states with leptons and b -jets with the ATLAS detector in s=7\sqrt{s}=7 TeV proton-proton collisions

The results of a search for pair production of light top squarks are presented, using 4.7 fb^-1 of sqrt(s) = 7 TeV proton-proton collisions collected with the ATLAS detector at the Large Hadron Collider. This search targets top squarks with masses similar to, or lighter than, the top quark mass. Final states containing exclusively one or two leptons (e, mu), large missing transverse momentum, light-jets and b-jets are used to reconstruct the top squark pair system. Global mass scale variables are used to separate the signal from a large ttbar background. No excess over the Standard Model expectations is found. The results are interpreted in the framework of the Minimal Supersymmetric Standard Model, assuming the top squark decays exclusively to a chargino and a b-quark. Light top squarks with masses between 123-167 GeV are excluded for neutralino masses around 55 GeV