Menentukan Parameter Model Cauchy Untuk a (1,587) Konstan Bahan Polistirena

Dalam jurnal ini akan dilaporkan mengenai hasil karakterisasi optik lapisan tipis polistirena dengan metode Ellipsometri. Berdasarkan model Dispersi Cauchy yang digunakan sebagai model untuk menunjukkan hubungan dispersi normal bahan transparan seperti Polistirena. Metode komputasi yang dibangun pada penelitian ini parameter Cauchy maupun ketebalan d dari bahan Polistirena dapat diprediksi, dengan A konstan sebesar 1,587 untuk bahan Polistirena dengan Pelarut Toluena B = 45560,60366; C = -68,850229; d = 5,743782 dan error = 0,10828. Sedangkan untuk pelarut Xilena B = 19,155923; C = -56,078811; d = 0,1 x 10-5-dan error 2,2916. Hasil dengan pelarut berbedasaat A konstan menunjukkan perbedaan indeks bias dan ketebalan yang juga mempengaruhi keadaan polarisasi cahaya

Studi pendahuluan lebah madu di beberapa daerah di Kecamatan Wamena dan sekitarnya, Jayawijaya, Irian Jaya

Kata kunci: lebah madu, Apis cerana, Koloni, Produksi, Lingaka

Evaluasi Proses Pembuatan Avtur (Aviation Turbine) Berdasarkan Analisa Sifat Fisik Dan Kimia Minyak Mentah (Crude Oil) Di PT Pertamina Ru II Dumai

Aviation Turbine Fuel (AVTUR) atau secara Internasional lebih dikenal dengan nama Jet A-1 adalah bahan bakaruntuk pesawat terbang jenis jet (baik tipe jet propusion atau propeller.) Avtur adalah minyak tanah dengan spesifikasiyang diperketat, terutama mengenai titik uap, dan titik beku. Secara umum, avtur memiliki kualitas yang lebih tinggidibandingkan bahan bakar yang digunakan untuk pemakaian yang kurang ‘genting\u27 seperti pemanasan atautransportasi darat. PT Pertamina RU II Dumai adalah salah satu Perusahan pengolahan yang menghasilkan berbagaiproduk akhir atau produk turunan dari minyak mentah.Untuk melakukan proses pengolahan pada minyak mentahperlu dikatahui karakteristik dan spesifikasi dari minyak mentah (bahan baku) yang akan diolah Untuk mengetahuimutu dan manfaat minyak bumi tersebut,ada beberapa parameter analisa minyak bumi yang digunakan yang terbagidalam 2 parameter yaitu parameter fisik dan parameter kimia.Dari analisa tersebut diketahui Bahan baku minyakmentah daerah Duri ( Duri Crude ) tipe “Naphthenic-naphthanic” dan Minas ( Minas Crude ) tipe “Paraffinicintermediate”.Penulis membuat perhitungan material balance bahwa Produksi Avtur secara aktual berkisar 8,35 %dari jumlah feed umpan dari kilang dumai 127 bbl dan kilang SPK 49 bbl.Mutu dan kualitas hasil produksi bahanbakar jenis Avtur (Aviation Turbine) kilang pertamina RU II Dumai baik dan memenuhi syarat dan spesifikasi yangditetapkan serta layak dipasarkan

Biodiversity into your hands - A call for a virtual global natural history 'metacollection'

10.1186/1742-9994-10-55Frontiers in Zoology101

Phylogeny and evolution of life-history strategies in the Sycophaginae non-pollinating fig wasps (Hymenoptera, Chalcidoidea)

<p>Abstract</p> <p>Background</p> <p>Non-pollinating Sycophaginae (Hymenoptera, Chalcidoidea) form small communities within <it>Urostigma </it>and <it>Sycomorus </it>fig trees. The species show differences in galling habits and exhibit apterous, winged or dimorphic males. The large gall inducers oviposit early in syconium development and lay few eggs; the small gall inducers lay more eggs soon after pollination; the ostiolar gall-inducers enter the syconium to oviposit and the cleptoparasites oviposit in galls induced by other fig wasps. The systematics of the group remains unclear and only one phylogeny based on limited sampling has been published to date. Here we present an expanded phylogeny for sycophagine fig wasps including about 1.5 times the number of described species. We sequenced mitochondrial and nuclear markers (4.2 kb) on 73 species and 145 individuals and conducted maximum likelihood and Bayesian phylogenetic analyses. We then used this phylogeny to reconstruct the evolution of Sycophaginae life-history strategies and test if the presence of winged males and small brood size may be correlated.</p> <p>Results</p> <p>The resulting trees are well resolved and strongly supported. With the exception of <it>Apocrytophagus</it>, which is paraphyletic with respect to <it>Sycophaga</it>, all genera are monophyletic. The Sycophaginae are divided into three clades: (i) <it>Eukoebelea</it>; (ii) <it>Pseudidarnes</it>, <it>Anidarnes </it>and <it>Conidarnes </it>and (iii) <it>Apocryptophagus</it>, <it>Sycophaga </it>and <it>Idarnes</it>. The ancestral states for galling habits and male morphology remain ambiguous and our reconstructions show that the two traits are evolutionary labile.</p> <p>Conclusions</p> <p>The three main clades could be considered as tribes and we list some morphological characters that define them. The same biologies re-evolved several times independently, which make Sycophaginae an interesting model to test predictions on what factors will canalize the evolution of a particular biology. The ostiolar gall-inducers are the only monophyletic group. In 15 Myr, they evolved several morphological adaptations to enter the syconia that make them strongly divergent from their sister taxa. Sycophaginae appears to be another example where sexual selection on male mating opportunities favored winged males in species with small broods and wingless males in species with large broods. However, some species are exceptional in that they lay few eggs but exhibit apterous males, which we hypothesize could be due to other selective pressures selecting against the re-appearance of winged morphs.</p

Optimisation of biomass, exopolysaccharide and intracellular polysaccharide production from the mycelium of an identified Ganoderma lucidum strain QRS 5120 using response surface methodology

Wild-cultivated medicinal mushroom Ganoderma lucidum was morphologically identified and sequenced using phylogenetic software. In submerged-liquid fermentation (SLF), biomass, exopolysaccharide (EPS) and intracellular polysaccharide (IPS) production of the identified G. lucidum was optimised based on initial pH, starting glucose concentration and agitation rate parameters using response surface methodology (RSM). Molecularly, the G. lucidum strain QRS 5120 generated 637 base pairs, which was commensurate with related Ganoderma species. In RSM, by applying central composite design (CCD), a polynomial model was fitted to the experimental data and was found to be significant in all parameters investigated. The strongest effect (p lt 0.0001) was observed for initial pH for biomass, EPS and IPS production, while agitation showed a significant value (p lt 0.005) for biomass. By applying the optimized conditions, the model was validated and generated 5.12 g/L of biomass (initial pH 4.01, 32.09 g/L of glucose and 102 rpm), 2.49 g/L EPS (initial pH 4, 24.25 g/L of glucose and 110 rpm) and 1.52 g/L of IPS (and initial pH 4, 40.43 g/L of glucose, 103 rpm) in 500 mL shake flask fermentation. The optimized parameters can be upscaled for efficient biomass, EPS and IPS production using G. lucidum

Fabrication and viscoelastic characteristics of waste tire rubber based magnetorheological elastomer

In this study, waste tire rubber (WTR) was successfully converted into magnetorheological (MR) elastomer via high-pressure and high-temperature reclamation. The physical and rheological properties of WTR based MR elastomers were assessed for performance. The revulcanization process was at the absence of magnetic fields. Thus, the magnetizable particles were allowed to distribute randomly. To confirm the particle dispersion in the MR elastomer matrix, an observation by scanning electron microscopy was used. The magnetization saturation and other magnetic properties were obtained through vibrating sample magnetometer. Rheological properties including MR effect were examined under oscillatory loadings in the absence and presence of magnetic fields using rotational rheometer. The WTR based MR elastomer exhibited tunable intrinsic properties under presentation of magnetic fields. The storage and loss modulus, along with the loss factor, changed with increases in frequency and during magnetization. Interestingly, a Payne effect phenomenon was seen in all samples during dynamic swept strain testing. The Payne effect was significantly increased with incremental increases in the magnetic field. This phenomenon was interpreted as the process of formation-destruction-reformation undergone by the internal network chains in the MR elastomers

A Peculiar New Genus and Species of Entedoninae (Chalcidoidea: Eulophidae) from Southeast Asia

Volume: 9Start Page: 170End Page: 17

Melihat Nabi SAW shalat: panduan lengkap, praktis dan shahih shalat Nabi

151 hlm. ; 21 cm

A new class of magnetorheological elastomers based on waste tire rubber and the characterization of their properties

© 2016 IOP Publishing Ltd. This paper proposes a new type of magnetorheological elastomer (MRE) using rubber from waste tires and describes its performance characteristics. In this work, scrap tires were utilized as a primary matrix for the MRE without incorporation of virgin elastomers. The synthesis of the scrap tire based MRE adopted a high-temperature high-pressure sintering technique to achieve the reclaiming of vulcanized rubber. The material properties of the MRE samples were investigated through physical and viscoelastic examinations. The physical tests confirmed several material characteristics - microstructure, magnetic, and thermal properties-while the viscoelastic examination was conducted with a laboratory-made dynamic compression apparatus. It was observed from the viscoelastic examination that the proposed MRE has magnetic-field-dependent properties of the storage modulus, loss modulus, and loss tangent at different excitation frequencies and strain amplitudes. Specifically, the synthesized MRE showed a high zero field modulus, a reasonable MR effect under maximum applied current, and remarkable damping properties