PENGARUH CAMPURAN LIMBAH BATUBARA (FLY ASH) TERHADAP SIFAT PLASTISITAS TANAH BERDASARKAN UJI CONE PENETROMETER

Tanah merupakan tempat berdirinya berbagai macam jenis konstruksi, yang sering menjadi masalah jika tanah tersebut memiliki sifat-sifat buruk seperti kadar air tinggi, plastisitas tinggi, potensi kembang susut yang tinggi. penambahan zat tambah (aditif) dengan memanfaatkan limbah batu bara (fly ash) merupakan salah satu usaha yang dapat dilakukan untuk memperbaiki tanah tersebut. Tujuan penelitian ini adalah untuk mengetahui sifat plastisitas tanah setelah ditambahkan fly ash dan dilakukan pemeraman. Pada penelitian ini tanah yang digunakan tanah di daerah Jalan Karet, Kec. Sui Beliung, Pontianak Barat, Kalimantan Barat. Pengujian laboratorium yang dilakukan adalah pengujian sifat fisik tanah dengan variasi campuran fly ash 5, 10, 20 dan 40% serta lama waktu curing 0, 7, 14 dan 28 hari. Pengujian batas cair (LL) menggunakan cone penetrometer. Penurunan nilai batas cair (LL) terbesar adalah pada campuran fly ash 40%  sebesar 39,45 % dengan lama Pemeraman 28 hari dan nilai batas plastis (PL) terbesar adalah pada campuran fly ash 40% sebesar 25,283% dengan lama pemeraman 0 hari. Nilai batas cair (LL) dan batas plastis (PL) mengalami penurunan, membuat nilai Indeks Plastisitas nya (PI) juga menurun, penambahan fly ash menyebabkan bertambahnya fraksi butiran kasar sehingga tertutupnya sebagian pori-pori tanah membuat tanah menjadi kurang sensitif terhadap perubahan kadar air.Kata kunci: fly Ash, plastisitas tanah, cone penetromete

Venture Capital Booms and Startup Financing

We review the growing literature on the relationship between venture capital booms and startup financing, focusing on three broad areas: First, we discuss the drivers of large inflows into the venture capital asset class, particularly in recent years -- which are related to but also distinct from macroeconomic business cycles and stock market fluctuations. Second, we review the emerging literature on the real effects of venture capital financing booms. A particular focus of this work is to highlight the potential impact that booms (and busts) can have on the types of firms that VCs choose to fund and terms at which they are funded, independent of investment opportunities -- thereby shaping the trajectory of innovation being conducted by startups. Third, an important insight from recent research is that booms in venture capital financing are not just a temporal phenomenon but can also be seen in terms of the concentration of VC investment in certain industries and geographies. We also review the role of government policy, exploring the degree to which it can explain the concentration of VC funding in the US over the past forty years in just two broad areas – information and communication technologies (ICT) and biotechnology. We conclude by highlighting promising areas of further research

Validation Aspects of Water Treatment Systems for Pharmaceutical Products

The goal of conducting validation is to demonstrate that a process, when operated within established limits, produces a product of consistent and specified quality with a high degree of assurance. Validation of water treatment systems is necessary to obtain water with all desired quality attributes. This also provides a framework to establish a total control over the process which monitors safety, efficacy and ultimately, the process outcomes. The present overview is an attempt to discuss various aspects of validation including different approaches, components of water treatment systems, equipment qualifications, phases of performance testing, documentation and post-validation monitoring.Keywords: Validation; Water treatment systems; Quality attributes; Pharmaceutical product

Pengaruh Kompetensi Individu, Insentif, dan Motivasi Intrinsik terhadap Kinerja Pegawai Perum Bulog Divre Kampar

This research was aims in Perum Bulog Divre Kampar. The purpose of this study was to determine 1) To determine the effect of individual competence, incentives and intrinsic motivation simultaneously on the performance of Employees Perum Bulog Divre Kampar. 2) To determine the effect of individual competence, incentives and intrinsic motivation partially on employee performance Perum Bulog Divre Kampar. 3) To determine which variables are the most significant influence on employee performance of Perum Bulog Divre Kampar. The number of samples in this study were 56 employees Perum Bulog Divre Kampar.The results of this study resulted in 1) There is the influence of individual competencies, incentives and intrinsic motivation simultaneously on the performance of Employees Perum Bulog Divre Kampar. 2) influences of individual competencies, incentives and intrinsic motivation partially on employee performance Perum Bulog Divre Kampar.3) individual competence is the most significant variable effect on employee performance Perum Bulog Divre Kampar.Keywords: Individuals Competence, Incentives, Intrinsic Motivation, Performance

Surface excitonic emission and quenching effects in ZnO nanowire/nanowall systems: limiting effects on device potential.

We report ZnO nanowire/nanowall growth using a two-step vapour phase transport method on a-plane sapphire. X-ray diffraction and scanning electron microscopy data establish that the nanostructures are vertically well-aligned with c-axis normal to the substrate, and have a very low rocking curve width. Photoluminescence data at low temperatures demonstrate the exceptionally high optical quality of these structures, with intense emission and narrow bound exciton linewidths. We observe a high energy excitonic emission at low temperatures close to the band-edge which we assign to the surface exciton in ZnO at ~ 3.366 eV, the first time this feature has been reported in ZnO nanorod systems. This assignment is consistent with the large surface to volume ratio of the nanowire systems and indicates that this large ratio has a significant effect on the luminescence even at low temperatures. The band-edge intensity decays rapidly with increasing temperature compared to bulk single crystal material, indicating a strong temperature-activated non-radiative mechanism peculiar to the nanostructures. No evidence is seen of the free exciton emission due to exciton delocalisation in the nanostructures with increased temperature, unlike the behaviour in bulk material. The use of such nanostructures in room temperature optoelectronic devices appears to be dependent on the control or elimination of such surface effects

Electronic structure of the substitutional vacancy in graphene: Density-functional and Green's function studies

We study the electronic structure of graphene with a single substitutional vacancy using a combination of the density-functional, tight-binding, and impurity Green's function approaches. Density functional studies are performed with the all-electron spin-polarized linear augmented plane wave (LAPW) method. The three $sp^2 \sigma$ dangling bonds adjacent to the vacancy introduce localized states (V$\sigma$) in the mid-gap region, which split due to the crystal field and a Jahn-Teller distortion, while the $p_z \pi$ states introduce a sharp resonance state (V$\pi$) in the band structure. For a planar structure, symmetry strictly forbids hybridization between the $\sigma$ and the $\pi$ states, so that these bands are clearly identifiable in the calculated band structure. As for the magnetic moment of the vacancy, the Hund's-rule coupling aligns the spins of the four localized V$\sigma_1 \uparrow \downarrow$, V$\sigma_2 \uparrow$, and the V$\pi \uparrow$ electrons resulting in a S=1 state, with a magnetic moment of $2 \mu_B$, which is reduced by about $0.3 \mu_B$ due to the anti-ferromagnetic spin-polarization of the $\pi$ band itinerant states in the vicinity of the vacancy. This results in the net magnetic moment of $1.7 \mu_B$. Using the Lippmann-Schwinger equation, we reproduce the well-known $\sim 1/r$ decay of the localized V$\pi$ wave function with distance and in addition find an interference term coming from the two Dirac points, previously unnoticed in the literature. The long-range nature of the V$\pi$ wave function is a unique feature of the graphene vacancy and we suggest that this may be one of the reasons for the widely varying relaxed structures and magnetic moments reported from the supercell band calculations in the literature.Comment: 24 pages, 15 figures. Accepted for publication in New Journal of Physic

Introduction to half-metallic Heusler alloys: Electronic Structure and Magnetic Properties

Intermetallic Heusler alloys are amongst the most attractive half-metallic systems due to the high Curie temperatures and the structural similarity to the binary semiconductors. In this review we present an overview of the basic electronic and magnetic properties of both Heusler families: the so-called half-Heusler alloys like NiMnSb and the the full-Heusler alloys like Co$_2$MnGe. \textit{Ab-initio} results suggest that both the electronic and magnetic properties in these compounds are intrinsically related to the appearance of the minority-spin gap. The total spin magnetic moment $M_t$ scales linearly with the number of the valence electrons $Z_t$, such that $M_t=Z_t-24$ for the full-Heusler and $M_t=Z_t-18$ for the half-Heusler alloys, thus opening the way to engineer new half-metallic alloys with the desired magnetic properties.Comment: 28 pages, submitted for a special issue of 'Journal of Physics D: Applied Physics' on Heusler alloy

Spectral evidence for jets from Accreting Millisecond X-ray Pulsars

Transient radio emission from X-ray binaries is associated with synchrotron emission from collimated jets that escape the system, and accreting millisecond X-ray pulsars (AMXPs) are no exception. Although jets from black hole X-ray binaries are well-studied, those from neutron star systems appear much fainter, for reasons yet uncertain. Jets are usually undetectable at higher frequencies because of the relative brightness of other components such as the accretion disc. AMXPs generally have small orbital separations compared with other X-ray binaries and as such their discs are relatively faint. Here, I present data that imply jets in fact dominate the radio-to-optical spectrum of outbursting AMXPs. They therefore may provide the best opportunity to study the behaviour of jets produced by accreting neutron stars, and compare them to those produced by black hole systems.Comment: 4 pages, 2 figures, to appear in the proceedings of "A Decade of Accreting Millisecond X-ray Pulsars", Amsterdam, April 2008, eds. R. Wijnands et al. (AIP Conf. Proc.