PENGARUH CUTTING SPEED TERHADAP KEKASARAN PERMUKAAN BAHAN ALLUMININIUM ALLOY 6061 PADA PROSES PEMBUBUTAN

Pada proses pembubutan benda kerja logam terdapat beberapa faktor yang mempengaruhi tingkat kekasaran permukaan benda kerja. Selalin geometri sudut mata pahat, parameter pemotongan memberi pengaruh terhadap hasil yang diperoleh. Penelitian ini dilakukan bertujuan untuk mengetahui pengaruh parameter kecepatan potong terhadap kekasaran permukaan pada pembubutan benda kerja aluminium alloy 6061, Penelitian ini dilakukan dengan memvariasikan lima kecepatan pemotongan yaitu 200, 300, 400, 500 dan 600 m/min. Setiap kali selesai proses pemesinan dengan menggunakan masing-masing kecepatan pemotongan tersebut, benda kerja hasil pembubutan dilakukan pengukuran kekasaran permukaannya dengan menggunakan alat ukur surface test Mitotoyo tipe 211 dengan pengambilan panjang spesimen sebesar 0,25 mm. hasil penelitian diperoleh bahwa pada setiap kenaikan kecepatan potong dengan kelipatan 100 m/min maka angka penurunan kekasaran permukaan dengan TNR=0.4 adalah sebesar 9.98%, TNR=0.8 adalah sebesar 6.21% , dan TNR 1.2 adalah 3.23%. Selanjutnya, setiap pembesaran tool nose radius dengan kelipatan 0.4 mm  dihasilkan rata-rata  penurunan harga kekasaran permukaan pada Vc =200m/min adalah sebesar 26.3 %, pada Vc=300m/min adalah 22.66% , Vc= 400 m/min adalah 14.53% , Vc 500m/min adalah 12.24%, dan Vc=600m/min adalah 13.73

Trabajos de metales (del hierro y sus artífices españoles). Noticia histórica de la cuchillería y de los cuchilleros antiguos en España

Artículo publicado en el Almanaque del Museo de la IndustriaCopia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-201

Effect of rotational shepherding on demographic and genetic connectivity of calcareous grassland plants

Response to habitat fragmentation may not be generalized among species, in particular for plant communities with a variety of dispersal traits. Calcareous grasslands are one of the most species-rich habitats in Central Europe, but abandonment of traditional management has caused a dramatic decline of calcareous grassland species. In the Southern Franconian Alb in Germany, reintroduction of rotational shepherding in previously abandoned grasslands has restored species diversity, and it has been suggested that sheep support seed dispersal among grasslands. We tested the effect of rotational shepherding on demographic and genetic connectivity of calcareous grassland specialist plants and whether the response of plant populations to shepherding was limited to species dispersed by animals (zoochory). Specifically, we tested competing dispersal models and source and focal patch properties to explain landscape connectivity with patch-occupancy data of 31 species. We fitted the same connectivity models to patch occupancy and nuclear microsatellite data for the herb Dianthus carthusianorum (Carthusian pink). For 27 species, patch connectivity was explained by dispersal by rotational shepherding regardless of adaptations to zoochory, whereas population size (16% species) and patch area (0% species) of source patches were not important predictors of patch occupancy in most species. [Correction made after online publication, February 25, 2014: Population size and patch area percentages were mistakenly inverted, and have now been fixed.] Microsite diversity of focal patches significantly increased the model variance explained by patch occupancy in 90% of the species. For D. carthusianorum, patch connectivity through rotational shepherding explained both patch occupancy and population genetic diversity. Our results suggest shepherding provides dispersal for multiple plant species regardless of their dispersal adaptations and thus offers a useful approach to restore plant diversity in fragmented calcareous grasslands

Multiscale analysis of re-entrant production lines: An equation-free approach

The computer-assisted modeling of re-entrant production lines, and, in particular, simulation scalability, is attracting a lot of attention due to the importance of such lines in semiconductor manufacturing. Re-entrant flows lead to competition for processing capacity among the items produced, which significantly impacts their throughput time (TPT). Such production models naturally exhibit two time scales: a short one, characteristic of single items processed through individual machines, and a longer one, characteristic of the response time of the entire factory. Coarse-grained partial differential equations for the spatio-temporal evolution of a "phase density" were obtained through a kinetic theory approach in Armbruster et al. [2]. We take advantage of the time scale separation to directly solve such coarse-grained equations, even when we cannot derive them explicitly, through an equation-free computational approach. Short bursts of appropriately initialized stochastic fine-scale simulation are used to perform coarse projective integration on the phase density. The key step in this process is lifting: the construction of fine-scale, discrete realizations consistent with a given coarse-grained phase density field. We achieve this through computational evaluation of conditional distributions of a "phase velocity" at the limit of large item influxes.Comment: 14 pages, 17 figure

Influencia del pH y la temperatura en la adsorción de fenol en agua utilizando ceniza de bagazo de caña de azúcar

La remoción del fenol en medio acuoso mediante adsorcióncon ceniza de bagazo de caña de azúcar, fuellevada a cabo a diferentes temperaturas en este estudio.El rango de pH donde ocurre el máximo por cientode remoción de fenol es 6,85 - 7,09. Para el estudio deadsorción a batch la ceniza tomada directamente delhorno de un Central Azucarero fue preparada y unapequeña cantidad de esta, se puso en contacto consoluciones acuosas de fenol, de concentraciones entre31,25 y 500 mg/L, a pH 7. Los experimentos a diferentestemperaturas muestran un máximo valor promediodel por ciento de remoción de fenol de 62,8 % a 27°C. La isoterma del modelo de Langmuir, fue la másapropiada para describir el proceso de adsorción y elmayor valor para la capacidad máxima de adsorción enla monocapa (Q0) fue de 142,86 mg/g a 40 °C. Todaslas concentraciones de fenol en la fase acuosa fuerondeterminadas mediante espectrometría UV-Visible

Determinants Preeclampsia in Pregnancy at Rsup Dr. Mohammad Hoesin Palembang

Background: Preeclampsia is pregnancy hypertension disorder that significantly affect morbidity and maternal mortality word-wide. Preeclampsia occurs in 5-7% of all pregnancies and is the leading cause of maternal death in the developing world. The purpose of this research was to identify risk factors associated with the incidence of preeclampsia in pregnant women at the Hospital Dr. Mohammad Hoesin Palembang in 2015. Methods: This research used a case-control study design. The data used secondary data from mothers medical record with preeclampsia and without preeclampsia in the period 1 January 2015-31 December 2015. The number of samples was 85 cases and controls. Analysis of data used univariate, bivariat analysis used chi square test, and multivariate used multiple logistic regression prediction model. Results: Multivariate analysis showed that factors associated with preeclampsia were age> 35 years (OR: 4.120; 95% CI: 1.715 to 9.897) obesity (OR: 2.134; 95% CI: 1.093 to 4.167) and a history of hypertension (OR: 12.143; 95% CI: 1.368 to 107.792). Conclusion: The most dominant factor related to the incidence of preeclampsia in pregnant women is a history of hypertension. The advice can be given that the relevant agencies to improve promotive and preventive efforts by providing socialization of the factors which may be a risk of preeclampsia so that cases of preeclampsia can be prevented at an early stage

Finding diamonds in the rough: Targeted Sub-threshold Search for Strongly-lensed Gravitational-wave Events

Strong gravitational lensing of gravitational waves can produce duplicate signals separated in time with different amplitudes. We consider the case in which strong lensing produces identifiable gravitational-wave events and weaker sub-threshold signals hidden in the noise background. We present a search method for the sub-threshold signals using reduced template banks targeting specific confirmed gravitational-wave events. We apply the method to all events from Advanced LIGO's first and second observing run O1/O2. Using GW150914 as an example, we show that the method effectively reduces the noise background and raises the significance of (near-) sub-threshold triggers. In the case of GW150914, we can improve the sensitive distance by $2.0\% - 14.8\%$. Finally, we present the top $5$ possible lensed candidates for O1/O2 gravitational-wave events that passed our nominal significance threshold of False-Alarm-Rate $\leq 1/30$ days

Directed dispersal by rotational shepherding supports landscape genetic connectivity in a calcareous grassland plant

Directed dispersal by animal vectors has been found to have large effects on the structure and dynamics of plant populations adapted to frugivory. Yet, empirical data are lacking on the potential of directed dispersal by rotational grazing of domestic animals to mediate gene flow across the landscape. Here, we investigated the potential effect of large-flock shepherding on landscape-scale genetic structure in the calcareous grassland plant Dianthus carthusianorum, whose seeds lack morphological adaptations to dispersal to animals or wind. We found a significant pattern of genetic structure differentiating population within grazed patches of three nonoverlapping shepherding systems and populations of ungrazed patches. Among ungrazed patches, we found a strong and significant effect of isolation by distance (r = 0.56). In contrast, genetic distance between grazed patches within the same herding system was unrelated to geographical distance but significantly related to distance along shepherding routes (r = 0.44). This latter effect of connectivity along shepherding routes suggests that gene flow is spatially restricted occurring mostly between adjacent populations. While this study used nuclear markers that integrate gene flow by pollen and seed, the significant difference in the genetic structure between ungrazed patches and patches connected by large-flock shepherding indicates the potential of directed seed dispersal by sheep across the landscape