Optimasi Dosis Pupuk Majemuk NPK dan Kalsium pada Bibit Kelapa Sawit (Elaeis Guineensis Jacq.) di Pembibitan Utama

This research was aimed to evaluate the rates of NPK and calcium fertilizers for the growth of oil palm seedling at main nursery. It was conducted in IPB Experimental Station, Cikabayan, Darmaga, Bogor from December 2011 to November 2012. The two factors, NPK and calcium, were arranged in a randomized block design with three replications. The rates of NPK fertilizer (15-15-15) were 0, 115, 230 and 460 g seedling-1. The rates of calcium fertilizer were 0, 5, 10 and 20 g seedling-1. There was no interaction effect observed between NPK and calcium fertilizer. NPK fertilizer, however had the significant quadratic effect on plant height, leaf number, stem diameter and chlorophyll content. Based on morphology variables, recommended optimum rate of NPK 15-15-15 fertilizer was 333 g seedling-1 for eight months. Thus, NPK rates were 7.00, 7.00, 19.45, 59.25, 66.3, 61.55, 58.97 and 54.16 g seedling-1 from first to eight month respectively. The optimum rate of calcium fertilizer was not determined in this experiment

Quarter-wave layers with 50% reflectance for obliquely incident unpolarized light

The conditions under which light interference in a transparent quarter-wave layer of refractive index n1 on a transparent substrate of refractive index n2 leads to 50% reflectance for incident unpolarized light at an angle φ are determined. Two distinct solution branches are obtained that correspond to light reflection above and below the polarizing angle, φp , of zero reflection for p polarization. The real p and s amplitude reflection coefficients have the same (negative) sign for the solution branch φ\u3eφp and have opposite signs for the solution branch φ\u3cφp . Operation at φ\u3cφp is the basis of a 50%–50% beam splitter that divides an incident totally polarized light beam (with p and s components of equal intensity) into reflected and refracted beams of orthogonal polarizations [ Opt. Lett. 31, 1525 (2006) ] and requires a film refractive indexn1⩾(2√+1)n2−−√ . A monochromatic design that uses a high-index TiO2 thin film on a low-index MgF2substrate at 488 nm wavelength is presented as an example

Principal angles and principal azimuths of frustrated total internal reflection and optical tunneling by an embedded low-index thin film

The condition for obtaining a differential (or ellipsometric) quarter-wave retardation when p- and s-polarized light of wavelength λ experience frustrated total internal reflection (FTIR) and optical tunneling at angles of incidence ϕ≥ the critical angle by a transparent thin film (medium 1) of low refractive index n1 and uniform thickness d, which is embedded in a transparent bulk medium 0 of high refractive index n0 takes the simple form: −tanh2x=tanδptanδs , in whichx=2πn1(d/λ)(N2sin2ϕ−1)1/2 , N=n0/n1 , and δp , δs are 01 interface Fresnel reflection phase shifts for the pand s polarizations. From this condition, the ranges of the principal angle and normalized film thickness d/λ are obtained explicitly. At a given principal angle, the associated principal azimuths ψr , ψt in reflection and transmission are determined by tan2ψr=−sin2δs/sin2δp and tan2ψt=−tanδp/tanδs , respectively. At a unique principal angle ϕegiven by sin2ϕe=2/(N2+1) , ψr=ψt=45° and linear-to-circular polarization conversion is achieved upon FTIR and optical tunneling simultaneously. The intensity transmittances of p- and s-polarized light at any principal angle are given byτp=tanδp/tan(δp−δs) and τs=−tanδs/tan(δp−δs) , respectively. The efficiency of linear-to-circular polarization conversion in optical tunneling is maximum at ϕe

Reflection coefficients of p- and s-polarized light by a quarter-wave layer: explicit expressions and application to beam splitters

The complex-amplitude reflection coefficients of p- and s-polarized light by a transparent freestanding, embedded, or deposited quarter-wave layer (QWL) are derived as explicit functions of the angle of incidence and layer refractive index. This provides the basis for the design of 50%-50% beam splitters for incident s-polarized or unpolarized light that use a high-index (e.g., TiO2 or Ge) QWL embedded in a glass cube in the visible and near infrared spectral range. These simple devices have good angular and spectral response and are insensitive to small film thickness errors to the first order

Single-layer-coated beam splitters for the division-of-amplitude photopolarimeter

A design procedure is presented for a near-optimal, single-layer-coated prism beam splitter that serves as the key optical element of the division-of-amplitude photopolarimeter (DOAP). For given film and substrate refractive indices, the angle of incidence and film thickness are selected such that the ellipsometric differential phase shifts in reflection and transmission Delta_r and Delta_t differ by ±pi/2, and the normalized determinant of the instrument matrix is maximized. The best results are obtained by using high-index films on low-index substrates. This is illustrated by examples of ZnS and GaP films on silica prisms in the visible and Si, Ge, and PbTe films on Irtran 1 substrates in the infrared. A 16° Si-prism DOAP beam splitter at the 1.55-µm lightwave-communications wavelength is also presented. It uses a 163-nm SiO2 coating on the entrance face to satisfy the optimum delta condition at 73° incidence, and the determinant of the instrument matrix is 78.23% of its theoretical maximum. The exit face of the Si prism is antireflection coated with a 208-nm Si3N4 film

ANALISIS KONDISI EKSISTING PENAMPANG SUNGAI CISANGKUY HILIR MENGGUNAKAN HEC-RAS 4.1.0

Abstrak: Banjir yang terjadi akibat meluapnya Sungai Cisangkuy Hilir mengakibatkan kerugian yang besar mencakup kerugian fisik maupun non fisik. Meluapnya Sungai Cisangkuy Hilir tersebut disebabkan karena sungai tidak  mampu  lagi menampung  debit  banjir  yang terjadi.  Makalah ini membahas mengenai analisis kondisi penampang eksisting Sungai Cisangkuy Hilir terhadap debit banjir rencana (periode ulang 20 tahun) menggunakan software HEC-RAS. Penelitian kali ini menggunakan HEC-RAS dari mulai pembuatan model tiruan Sungai Cisangkuy Hilir sampai simulasi aliran model tersebut. Berdasarkan hasil simulasi, ( steady flow analysis) menggunakan debit banjir rencana periode ulang 20 tahun (229, 27 m3/s) bahwa semua penampang mengalami banjir dan tidak memenuhi persyaratan tinggi jagaan (0.75 meter). Tinggi banjir tertinggi terdapat pada stasiun 17,4 yaitu mencapai 3,06 meter sedangkan tinggi banjir terendah terdapat pada stasiun 0 yaitu sebesar 0,03 meter. Banjir tersebut disebabkan karena tinggi sedimen yang mencapai tiga meter di sepanjang sungai yang membuat kapasitas penampang menjadi kecil. Sehingga dapat diambil kesimpulan bahwa Sungai Cisangkuy Hilir memerlukan upaya penanganan banjir khususnya dengan normalisasi penampang sungai.Kata kunci: penampang, model, sedimen, simulasi, steadyAbstract: Floods caused by overflowing of the river downstream Cisangkuy cause large losses include loss of physical and non-physical. Cisangkuy River Downstream overflowing caused by the river no longer able to accommodate the flood discharge. This paper discusses the analysis of the existing conditions section Cisangkuy river downstream with discharge plan (20 year return period) using HEC-RAS software. This research using HEC-RAS ranging from artificial modeling Cisangkuy River downstream until flow simulation model. Based on simulation results, (steady flow analysis) using the flood discharge plan period of 20 years (229, 27 m3/s) that all the section was flooded and did not comply the freeboard (0.75 meters). The highest floods are on station 17.4, reaching 3.06 meters while the lowest was at station flood 0 is equal to 0.03 meters. The flood was caused by high sediment that reaches three meters along the river which makes a small cross-section capacity. So it can be concluded that the river downstream Cisangkuy require flood mitigation efforts in particular by normalizing the river section. Keywords: cross section, models, sediment, simulation, stead

Single-layer-coated beam splitters for the division-of-amplitude photopolarimeter

A design procedure is presented for a near-optimal, single-layer-coated prism beam splitter that serves as the key optical element of the division-of-amplitude photopolarimeter (DOAP). For given film and substrate refractive indices, the angle of incidence and film thickness are selected such that the ellipsometric differential phase shifts in reflection and transmission Delta_r and Delta_t differ by ±pi/2, and the normalized determinant of the instrument matrix is maximized. The best results are obtained by using high-index films on low-index substrates. This is illustrated by examples of ZnS and GaP films on silica prisms in the visible and Si, Ge, and PbTe films on Irtran 1 substrates in the infrared. A 16° Si-prism DOAP beam splitter at the 1.55-µm lightwave-communications wavelength is also presented. It uses a 163-nm SiO2 coating on the entrance face to satisfy the optimum delta condition at 73° incidence, and the determinant of the instrument matrix is 78.23% of its theoretical maximum. The exit face of the Si prism is antireflection coated with a 208-nm Si3N4 film

Acclimation to Hypoxia Increases Survival Time of Zebrafish, Danio rerio, during lethal hypoxia

Survivorship of zebrafish, Danio rerio, was measured during lethal hypoxic stress after pretreatment in water at either ambient oxygen or at a lowered, but nonlethal, level of oxygen. Acclimation to nonlethal hypoxia (pO2 @ 15 Torr; ca. 10% air-saturation) for 48 hr significantly extended survival time during more severe hypoxia (pO2 @ 8 Torr; ca. 5% air-saturation) compared to survival of individuals with no prior hypoxic exposure. The magnitude of the acclimation effect depended upon the sex of the fish: hypoxia pretreatment increased the survival times of males by a factor of approximately 9 and that of females by a factor of 3 relative to controls. In addition, survival time of control and hypoxia acclimated fish depended upon when in the year experiments were conducted. Survival times were 2–3 times longer when measured in the late fall or winter compared to survival times measured during the spring or summer. These results demonstrate a direct survival benefit of short-term acclimation to hypoxia in this genetically tractable fish. The fact that the acclimation effect depended upon the sex of the fish and the season during which experiments were conducted demonstrates that other genetic and/or environmental factors affect hypoxia tolerance in this species