Manipulation of Giant Faraday Rotation in Graphene Metasurfaces

Faraday rotation is a fundamental magneto-optical phenomenon used in various optical control and magnetic field sensing techniques. Recently, it was shown that a giant Faraday rotation can be achieved in the low-THz regime by a single monoatomic graphene layer. Here, we demonstrate that this exceptional property can be manipulated through adequate nano-patterning, notably achieving giant rotation up to 6THz with features no smaller than 100nm. The effect of the periodic patterning on the Faraday rotation is predicted by a simple physical model, which is then verified and refined through accurate full-wave simulations.Comment: 4 pages, 5 figures, submitted to Applied Physics Letter

INVESTIGATION OF THE EFFECTIVENESS OF AN INTEGRATED FLOODED-BED DUST SCRUBBER ON A LONGWALL SHEARER THROUGH LABORATORY TESTING AND CFD SIMULATION

Dust generation at an underground coal mine working face continues to be a health and safety issue. Prolonged exposure to high concentrations of airborne respirable dust can cause a debilitating and often fatal respiratory disease called Black Lung. In addition, the deposition of float dust in mine return airways poses a serious safety hazard if not sufficiently diluted with inert rock dust. A localized methane explosion can transition into a self-propagating dust explosion. Since dust is a byproduct of various mining activities, such as cutting and loading, crushing, and transportation, the dust-related issues cannot be totally eliminated. However, the adverse health effects and safety concerns can be minimized if a significant amount of the generated dust is removed from the ventilation air by a mechanical device, such as a dust scrubber. Over the last three decades, flooded-bed dust scrubbers integrated into continuous miners have been successfully applied for capturing and removing airborne dust generated at the working face. According to the National Institute for Occupational Safety and Health (NIOSH), a flooded-bed scrubber can achieve more than 90% capture and cleaning efficiencies under optimum conditions. Although flooded-bed scrubbers have proven useful in the vast majority of cases, they have not yet been successfully applied to a longwall face. In the United States, numerous attempts have been made to reduce dust concentration at a longwall face through the application of a scrubber; but, none were successfully implemented. Encouraged by the successful use of a flooded-bed scrubber system at continuous miner faces, this research revisits the flooded-bed scrubber concept for a longwall shearer. For this investigation, a full-scale physical model of a Joy 7LS longwall shearer, modified with an integrated flooded-bed dust scrubber, was designed and fabricated at the University of Kentucky. The scope of work for this research was limited to capturing and cleaning dust generated near the shearer headgate drum only. The mock-up was transported to, and assembled in, the full-scale longwall dust gallery at the NIOSH Pittsburgh Research Laboratory (PRL). Tests were conducted to examine: (1) the effect of the scrubber on headgate-drum dust reduction and (2) the combined effect of the scrubber and splitter sprays on headgate drum dust reduction. Analysis of test results for the scrubber-alone condition indicates a significant dust reduction of up to 57% in the return airway and 85% in the test gallery walkway, whereas the combination of scrubber and splitter-arm sprays shows dust reduction of up to 61% and 96% in the return and walkway, respectively. These results indicate that a flooded-bed scrubber integrated into a longwall shearer can be used as a viable technique to reduce a large portion of airborne dust at a longwall face. Subsequently, a Computational Fluid Dynamics (CFD) model of the longwall gallery and shearer was developed and validated using the results of the experimental study. The CFD simulation results are in good agreement with the experimental results with a maximum of 9.7% variation. This validated CFD model can be used in future research to predict the effects of modifications to the scrubber system, including modifications to the scrubber inlet, to optimize the scrubber design, and to evaluate the effectiveness of adding a tailgate drum dust scrubber

Fetus-in-fetu: A Rare Congenital Anomaly

Two cases of fetus-in-fetu, on which we performed surgery in 2003 and 2006, are being reported. Both the cases presented with a lump in the abdomen. Radiology confirmed the diagnosis. The lumps were found in the retroperitoneum and successfully excised. Because of the rarity of the condition, these two cases are being reported with relevant salient features and are discussed in the light of available literature. Key words: Abdominal lump, axial skeleton, fetus-in-fetu, retroperitoneal, teratom

Analysis of Household Livelihood Structure and Strategies of Farmers in Conservation Forest Areas, Case in the Village of Cipeuteuy, District Sukabumi

Penduduk Desa Cipeuteuy masih menggantungkan kehidupan mereka dari kegiatan pertanian. Lahan yang digunakan adalah Taman Nasional Gunung Halimun Salak dan menggunakan prinsip pinjam pakai. Strategi nafkah warga yang tinggal di desa ini tidak hanya dari sektor pertanian, tapi juga sektor non pertanian. Terdapat berbagai cara penerapan struktur strategi penghidupan, mulai dari intensifikasi satu sektor, diversifikasi pendapatan atau pola nafkah ganda, rekayasa spasial atau migrasi. Namun, semua sektor pendapatan tetap menggunakan modal. Kelima modal yaitu modal sumberdaya alam, modal sosial, modal manusia, modal finansial, dan modal fisik digunakan sebagai cara untuk mendukung keberlanjutan strategi nafkah mereka. Bahkan semakin lama, warga cenderung lebih bergantung pada sektor non petanian. Namun basis nafkah mereka adalah sebagai petani. Hal ini dapat disimpulkan bahwa telah terjadi transformasi sosial dimana nilai pertanian terhadap masyarakat telah menurun

Manufacturing Process and Emerging Advantage of Graphene Based Composites in Aerospace- A Review

The cardinal pillar for this paper is to showcase the composition of Graphene-based composites and reveal the hidden uses of Graphene-based composites in aerospace dominion. This paper briefly discusses the different methods by which graphene-based composites can be synthesized mostly those with functional polymers and inorganic nanostructures and additionally covers a few of the applications of graphene-based composites such as lightweight, fire retardancy, and additive manufacturing. Moreover, this detailed paper also brings up crucial highlights where graphene-based composites have covered long distances from the research lab to commercialization, specifically focusing on aerospace industries

Korelasi Kepemimpinan Situasional Kepala Sekolah, Motivasi Kerja Dan Iklim Kerja Terhadap Kinerja Guru Pada Guru SMA Negeri 1 Tampaksiring

This study aims to find out and analyze: Are there significant correlations between situational leadership principals (X1), motivation ker (X2), the climate of teachers working on teacher performance (Y). This research is ex-post facto in the form of correlational with population of subjects include teachers at SMAN 1 Tampaksiring, which amounts to 45 people. Preparation of questionnaires conducted using Likert scale models. Data were analyzed using simple regression, multiple regression, and partial correlation analysis. The results showed that (1) The tendency of situational leadership teachers be in either category. There is a significant correlation between situational leadership with teacher performance with a correlation coefficient (rx1y) of 0.637 and the determination of 40.6%, (2) The tendency of teachers' work motivation in be in either category. There is a significant correlation between motivation and performance of teachers working, with a correlation coefficient (rx2y) of 0.882 and of determination of 77.8%. 3) The tendency of teachers working climate be in either category. There is a significant correlation with the performance of teachers working climate, with a correlation coefficient (rx3y) of 0.805 and of determination of 64.8% .4) tendency teacher performance be in either category 5) There is a significant correlation of leadership situational, work motivation and work climate together with the performance teacher, with a correlation coefficient (Ry123) of 0.950 and of determination (R2) of 90.2%

Hubungan Kualitas Pengelolaan, Supervisi Akademik Kepala Sekolah Dan Iklim Kerja Terhadap Kinerja Guru SMP Negeri Di Kabupaten Jembrana

This study was aimed at finding out the correlation between management quality, principal's academic supervision and work climate and teacher performance at public junior secondary schools in Jembrana regency. This study was an Expost Facto. There was only one type of instruments used to collect the data on the variables of management quality, principal's academic supervision, work climate and teacher performance, i.e., questionnaire. To determine the respondents, proportional random sampling technigue was used, i.e., by drawing the data at random from all members of the population of 169 teachers. The data were analyzed by using simple regression, multiple regression, and multiple regression. Based on the results of analyses some findings were found as follows. First, there was a significant correlation between management quality (X1) and teacher performance (Y) as shown by linear regression equation Y = 14.329 + 0.514 X1 with 27.7% contribution. Second, there was a significant correlation between principal's academic supervision (X2) and teacher performance (Y) as shown by linear regression equation Y = 127.549 + 0.610 X2 with 33.7% contribution. Third, there was a significant correlation between teacher's work climate (X2) and teacher performance (Y) as shown by linear regression Y= 142.963 + 0.513X3 with 27.9% contribution. Fourth, there was a significant contribution between management quality (X1), principal's academic supervision (X2), teacher's work climate (X3) and teacher performance (Y) as shown by linear regression equation Y = 0.272 X1 + 0.432X2 + 0.258 X3 + 77.045 with 52.5