Karakteristik Keramik Mgal2o4 Untuk Bahan Bakar Nuklir Matriks Inert (Imf) Yang Dibuat Dari Serbuk Hasil Hem Pada Suhu Sinter 1500oc

Terdapatkecenderungan bahwa di masa depan plutonium dan aktinida lain yang berumur panjangsebagai hasil samping PLTN akan menimbulkan masalah. Untuk mengatasi hal ini diperlukanbahan bakar reaktor daya yang lebih efisien. Salah satunya adalah bahan bakar matriks inert(IMF). Bahan bakar ini terdiri dari keramik yang inert (terhadap neutron) sebagai matriks danbahan fisil seperti uranium dioksida yang terdispersi atau larut padat di dalam matriks sebagaibahan bakarnya. Salah satu karakteristik yang diperlukan dari keramik matriks inert adalahrapat massa yang tinggi. Serbuk Al2O3 dan MgO dengan komposisi 50-50, 45-55 dan 55-45dalam % mol digerus dengan alat gerus listrik selama 1 Jam dan ball mill (HEM, high energymilling) selama 50 Jam. Serbuk hasil gerus dipres dengan tekanan 4 ton/cm2. Pelet hasil pres(mentah) kemudian disinter pada suhu 1500oC selama 2 Jam. Rapat masa pelet mentah dansinter ditentukan melalui penimbangan dan pengukuran dimensi. Pelet sinter selanjutnyadianalisis dengan difraksi sinar-x (XRD) dan mikroskop elektron (SEM). Hasil XRDmemperlihatkan bahwa semua keramik yang dibuat mempunyai struktur kristal kubik spinel.Keramik dengan komposisi 50-50 hasil HEM dapat disintesis dengan baik pada suhu 1500oCtetapi keramik yang sama dari serbuk awal tidak dapat disintesis dengan baik. Rapat massakeramik komposisi 45-55 dan 55-45 lebih rendah dari pada rapat massa keramik komposisi 50-50 karena ternyata kelebihan MgO dan Al2O3 tidak membentuk larutan padat spinel. Padasemua keramik fase kedua teramati. Meskipun serbuk hasil HEM lebih reaktif dari pada serbukawal, namun untuk mendapatkan rapat massa yang lebih tinggi waktu HEM perlu ditambah

Improved Quality of Color Sumatra Barb, Puntigrus Tetrazona (Bleeker, 1855) with Artificial Feed Enriched Red Spinach Flour (Amaranthus Tricolor L.)

Ikan sumatra albino (Puntigrus tetrazona) merupakan salah satu ikan hias asli Indonesia yang berasal dari pulau Sumatera. Budidaya ikan sumatra albino mengalami penurunan dalam kualitas warna karena spesies ini tidak dapat memproduksi karotenoid dalam tubuhnya. Guna mengatasi permasalahan ini, maka dibutuhkan sebuah alternatif berupa penambahan karotenoid dalam pakan. Penelitian ini bertujuan untuk mengkaji efektivitas dosis tepung bayam merah sebagai pakan terhadap kualitas warna ikan sumatra albino. Ikan hias sumatra albino dengan bobot 0,54 g dan panjang 3,50 cm dipelihara di dalam akuarium (30 cm x 20 cm x 20 cm).Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan empatperlakuan (A=0% (kontrol), B=2%, C=4%, dan D=6%) dan tiga ulangan. Parameter yang diamati meliputi nilai kualitas warna kulit ikan (L=lightness, C=chroma, dan H=hue) dan total karotenoid pada kulit, sirip,serta daging ikan sumatra albino. Ikan dipelihara selama 42 hari dan diberi pakan tigakali sehari. Hasil penelitian menunjukkan bahwapenambahantepung bayam merah pada dosis 6%dengan kandungan karotenoid 45,26 ppm pada pakan, 50,44 ppm pada sirip, 16,10 ppm pada kulit, dan 3,69 ppm pada daging, dapat meningkatkan kualitas warna ikan sumatra albino. Hal tersebut diindikasikan dengan menurunnya nilai L=60,83%, meningkatnya nilai C=20,57%, dan mempertahankan nilai H=87,09°

Geología de las Placas Scotia y Sandwich. Revisión y Mapa Geológico

Fil: Yamin, M.G. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales. Dirección de Geología Regional; Argentina.Fil: Anselmi, G. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales. Dirección de Geología Regional; Argentina.Esta contribución técnica está integrada por un mapa y una síntesis geológica de las placas Scotia y Sandwich, en el sector comprendido entre los paralelos 50° y 65° 40’ de latitud sur y los meridianos 78° y 19° 30’ de longitud oeste. El mapa se realizó a escala 1:7.500.000 sobre la base de la recopilación y el análisis de la información geológica y estructural del área. En el cuadro estratigráfico asociado se distinguieron cuatro sectores con características geológicas (litológicas y estructurales) afines, tales como: el sector continental de América del Sur y las islas Georgias del Sur, las islas Malvinas, las islas Sandwich del Sur y, finalmente, el sector norte de la península Antártica, las islas Shetland del Sur y las islas Orcadas del Sur. Asimismo, se compiló el mapa geológico de las islas Georgias del Sur, a escala 1:1.000.000. El material cartográfico se complementó con un breve texto e ilustraciones. Se incorporaron, además, algunos datos históricos y fotografías del repositorio institucional del Servicio Geológico Minero Argentino (SEGEMAR)

Competitive Performance of Carbon “Quantum” Dots in Optical Bioimaging

Carbon-based “quantum” dots or carbon dots are surface-functionalized small carbon nanoparticles. For bright fluorescence emissions, the carbon nanoparticles may be surface-doped with an inorganic salt and then the same organic functionalization. In this study, carbon dots without and with the ZnS doping were prepared, followed by gel-column fractionation to harvest dots of 40% and 60% in fluorescence quantum yields, respectively. These highly fluorescent carbon dots were evaluated for optical imaging in mice, from which bright fluorescence images were obtained. Of particular interest was the observed competitive performance of the carbon dots in vivo to that of the well-established CdSe/ZnS QDs. The results suggest that carbon dots may be further developed into a new class of high-performance yet nontoxic contrast agents for optical bioimaging

Visual comfort evaluation in presence of direct daylight in office

En regiones con clima árido y elevado número de días con cielo claro resulta muy ventajoso iluminar los espacios interiores con luz natural, logrando ahorros energéticos y beneficios en los usuarios. Para ello es necesario un adecuado análisis y control de la luz solar. En este trabajo se evaluaron 15 oficinas que presentan manchas de sol en el área de trabajo. Estas oficinas se evaluaron a través de métricas subjetivas y objetivas: nivel de iluminancia, relaciones de luminancia, riesgo de deslumbramiento, uniformidad, entre otras, tomándose como referencia las medidas subjetivas. Los resultados mostraron que de las 8 métricas evaluadas, sólo cuatro presentaron correlaciones moderadas r>0.5 con la sensación de los usuarios, la iluminancia vertical al ojo, análisis de luminancias en campo de visión cercana y valores de uniformidad utilizadas en conjunto son una herramienta más descriptiva de las escenas con luz natural. En este sentido, este estudio indica que es recomendable utilizar más de una métrica en escenas con luz natural, profundizando el análisis de imágenes HDR, cuyo poder de diagnóstico es aún poco aprovechado.In regions with arid climate and many clear-sky days it is very advantageous to illuminate the interior spaces with daylight, achieving energy savings and benefits for users. It is therefore necessary an adequate analysis and sunlight control. A total of 15 offices with sunspots over the work space were evaluated. These offices were evaluated through objective and subjective metrics developed to assess daylight spaces: level of illuminance, luminance ratios, risk of glare, uniformity, among others, taking as reference values subjective data. The results showed that of the 8 metric evaluated, only four showed moderate correlations r> 0,5 with users perception. Vertical illuminance at eye, luminance analysis in the near field of view and uniformity values were a more descriptive tool in daylight scenes used together. In this way, this study suggests that it is suitable the use of more than one metric in daylight scenes, deepening in the HDR-image analysis, whose diagnostic power is still an underdeveloped area.Eje: Paisajes sustentables (Actas).Facultad de Arquitectura y Urbanism

Cosmic ray tests of the D0 preshower detector

The D0 preshower detector consists of scintillator strips with embedded wavelength-shifting fibers, and a readout using Visible Light Photon Counters. The response to minimum ionizing particles has been tested with cosmic ray muons. We report results on the gain calibration and light-yield distributions. The spatial resolution is investigated taking into account the light sharing between strips, the effects of multiple scattering and various systematic uncertainties. The detection efficiency and noise contamination are also investigated.Comment: 27 pages, 24 figures, submitted to NIM

Unpacking ‘women’s health’ in the context of PPPs: a return to instrumentalism in development policy and practice?

There has been a significant increase in funding for health programmes in development over the last two decades, partly due to the formation of public–private partnerships. This article examines the impact of public–private partnerships from the perspective of women’s health, asks whether the current culture of funding has led to an increased instrumentalism in women’s health programming and what effects this has on how women’s health is addressed at the level of practice. The article is based on research carried out with UK-based non-governmental organisations (NGOs), and its conclusions raise further challenges for improving women’s health policies and programmes in development

Harnessing case isolation and ring vaccination to control Ebola.

As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts

Retrospective Analysis of the 2014-2015 Ebola Epidemic in Liberia.

The 2014-2015 Ebola epidemic has been the most protracted and devastating in the history of the disease. To prevent future outbreaks on this scale, it is imperative to understand the reasons that led to eventual disease control. Here, we evaluated the shifts of Ebola dynamics at national and local scales during the epidemic in Liberia. We used a transmission model calibrated to epidemiological data between June 9 and December 31, 2014, to estimate the extent of community and hospital transmission. We found that despite varied local epidemic patterns, community transmission was reduced by 40-80% in all the counties analyzed. Our model suggests that the tapering of the epidemic was achieved through reductions in community transmission, rather than accumulation of immune individuals through asymptomatic infection and unreported cases. Although the times at which this transmission reduction occurred in the majority of the Liberian counties started before any large expansion in hospital capacity and the distribution of home protection kits, it remains difficult to associate the presence of interventions with reductions in Ebola incidence