Quantum corrections to the entropy of charged rotating black holes

Hawking radiation from a black hole can be viewed as quantum tunneling of particles through the event horizon. Using this approach we provide a general framework for studying corrections to the entropy of black holes beyond semiclassical approximations. Applying the properties of exact differentials for three variables to the first law thermodynamics, we study charged rotating black holes and explicitly work out the corrections to entropy and horizon area for the Kerr-Newman and charged rotating BTZ black holes. It is shown that the results for other geometries like the Schwarzschild, Reissner-Nordstr\"{o}m and anti-de Sitter Schwarzschild spacetimes follow easily

Electrolyte Performance of Noni Fruit Extracts (Morinda Citrifolia L.) for C–Zn Batteries

C–Zn battery is a commercial battery that widely used due to its easy to carry, inexpensive, and easy to obtain. However, the serious thing is the problem of battery waste which not only causes pollution but also endangers natural resources due to contained heavy metals (Mn) and corrosive electrolytes. Noni (Morinda Citrifolia L.) is a fruit with the main component of vitamin C (ascorbic acid) as an antioxidant. This acid component is the basis for further utilization as an environmentally friendly electrolyte application. Noni was fermented with 2 time variations, 48 and 72 hours. Fabrication of C–Zn batteries was done with thin configurations like sandwiches. Furthermore, voltage was measured with digital multimeter. The results obtained, Open Circuit Voltage (OCV) of 0.72 V for unfermented electrolytes. Then, the use of fermented electrolytes causes an increase in voltage and current due to decreased pH

Ricci-flat Metrics with U(1) Action and the Dirichlet Boundary-value Problem in Riemannian Quantum Gravity and Isoperimetric Inequalities

The Dirichlet boundary-value problem and isoperimetric inequalities for positive definite regular solutions of the vacuum Einstein equations are studied in arbitrary dimensions for the class of metrics with boundaries admitting a U(1) action. We show that in the case of non-trivial bundles Taub-Bolt infillings are double-valued whereas Taub-Nut and Eguchi-Hanson infillings are unique. In the case of trivial bundles, there are two Schwarzschild infillings in arbitrary dimensions. The condition of whether a particular type of filling in is possible can be expressed as a limitation on squashing through a functional dependence on dimension in each case. The case of the Eguchi-Hanson metric is solved in arbitrary dimension. The Taub-Nut and the Taub-Bolt are solved in four dimensions and methods for arbitrary dimension are delineated. For the case of Schwarzschild, analytic formulae for the two infilling black hole masses in arbitrary dimension have been obtained. This should facilitate the study of black hole dynamics/thermodynamics in higher dimensions. We found that all infilling solutions are convex. Thus convexity of the boundary does not guarantee uniqueness of the infilling. Isoperimetric inequalities involving the volume of the boundary and the volume of the infilling solutions are then investigated. In particular, the analogues of Minkowski's celebrated inequality in flat space are found and discussed providing insight into the geometric nature of these Ricci-flat spaces.Comment: 40 pages, 3 figure

Kajian Tentang Tingkat Efisiensi Pelayanan Kesehatan Rumah Sakit Umum Pemerintah Kabupaten/Kota di Jawa Timur Menggunakan Metode PCA-DEA

Salah satu prioritas pembangunan provinsi Jawa Timur adalah meningkatkan kualitas pelayanan kesehatan. Kualitas pelayanan kesehatan dapat diukur melalui efisiensi pelayanan kesehatan di rumah sakit. Efisiensi yang dimaksud adalah adanya keseimbangan antara yang dilayani dan yang melayani, selanjutnya disebut sebagai output dan input. Pada penelitian ini ingin diketahui tingkat efisiensi 39 rumah sakit umum pemerintah Kabupaten/Kota di Jawa Timur dengan menggunakan metode Principal Component Analysis-Data Enpelovment Analysis (PCA-DEA) berorientasi input. Model yang digunakan yaitu DEA-CCR, DEA-BCC, PCA-CCR, dan PCA-BCC. Data input yang digunakan adalah sumber daya kesehatan di rumah sakit umum dan data output yang digunakan berupa jumlah pasien rawat inap dan jumlah pasien rawat jalan. Dari berbagai model PCA-DEA yang digunakan dihasilkan nilai efisiensi yang berbeda untuk rumah sakit umum yang sama dan hanya satu rumah sakit umum yang memiliki nilai efisiensi yang tetap atau konsisten diantara rumah sakit- rumah sakit tersebut, yaitu rumah sakit umum Kanjuruhan Kepanjen Malang

Motivasi Belajar sebagai Mediator Hubungan Kecerdasan Adversitas dan Prokrastinasi Akademik pada Mahasiswa yang Aktif Berorganisasi

: This research was aimed to reveal the influence of Adversity Quotient on academic procras- tination students actively involved in organizations either directly or through motivation. The research design utilized the cross sectional study and the cluster random sampling with 50 respondents. The instruments were Adversity Quotient questionnaires, motivation questionnaires, and academic procrastination questionnaires. Data were analyzed by using the path analysis. The findings showed that Adversity Quotient indirectly influenced academic procrastination without motivation and also Adversity Quotient indirectly influencedacademic procrastination through motivation