Dynamical Horizons: Energy, Angular Momentum, Fluxes and Balance Laws

Dynamical horizons are considered in full, non-linear general relativity. Expressions of fluxes of energy and angular momentum carried by gravitational waves across these horizons are obtained. Fluxes are local, the energy flux is positive and change in the horizon area is related to these fluxes. The flux formulae also give rise to balance laws analogous to the ones obtained by Bondi and Sachs at null infinity and provide generalizations of the first and second laws of black hole mechanics.Comment: 4 pages, RevTeX4. Minor typos corrected. To appear in Phys.Rev.Let

Optimization of molybdenite flotation using response surface method

Purpose. The paper is aimed to study the molybdenite flotation from a low-grade uranium ore containing 0.2% of Mo. Methods. Three control parameters including frother (MIBC) dosage, collector (gasoline) dosage and pH, each in five levels, were investigated. Response surface methodology (RSM) was performed for statistical design and analysis of experiments and process modeling. Four quadratic mathematical models were derived for prediction of Mo recovery and Mo grade. Findings. Analysis of variance showed that frother and collector dosage were the most significant factors affecting Mo recovery and grade. In process optimization, maximum values of Mo recovery and grade were achieved as 79.13% and 2.93%, respectively. Optimum frother concentration of 78.93 g/t, gasoline dosage of 507.70 g/t, and pH of 9.77, for Mo recovery were obtained. However, in optimization studies, a case proposed the model in which the same consumption of reagents is used. Originality. There is a recognized need for type of uranium ore which contains Molybdenite, therefore working on molybdenite removing from this ore helps to recover uranium in the next steps. This research provides a novel approach to gain the optimum recovery and grade to extract uranium so easily. Practical implications. This study showed that response surface methodology could be effectively used for flotation process modeling as well as finding an optimum condition to achieve maximum recovery and grade under minimum consumption of flotation reagents.Мета. Дослідження особливостей процесу флотації молібденіту з низькозбагаченої уранової руди, що містить 0.2% молібдену. Методика. Проаналізовано три контрольних параметра флотації – дозу спінювача (метил-ізобутил-карбінол), колекторне (газолінове) дозування і ph (кожен – у п’яти різницях рівнів). Для статистичного розрахунку, аналізу експериментів і моделювання процесу флотації застосовано метод поверхневого відклику (МПВ). Були розроблені чотири квадратичні математичні моделі для розрахункових даних отримання Мо і визначення його якості. Результати. Встановлено, що спінювач і колекторне дозування є найбільш впливовими факторами при отриманні Мо та його якості. У процесі оптимізації максимальні рівні отримання Мо та якості були, відповідно, 79.13% і 2.93%. Виявлено наступну оптимальну концентрацію для Мо: спінювач – 78.93 г/т, газолінове дозування – 507.70 г/т, pH – 9.7, що підтверджено моделюванням. Наукова новизна. Запропоновано інноваційний підхід для отримання легкого й оптимального способу відновлення і ступеня вилучення урану до високої якості. Практична значимість. Метод поверхневого відклику може ефективно застосовуватися для моделювання процесу флотації з метою визначення оптимальних умов досягнення максимальної рекуперації та якості при мінімальних витратах флотаційних реагентів.Цель. Исследование особенностей процесса флотации молибденита из низкообогащенной урановой руды, содержащей 0.2% молибдена. Методика. Проанализированы три контрольных параметра флотации – доза вспенивателя (метил-изобутил-карбинол), коллекторная (газолиновая) дозировка и pH (каждый – в пяти разностях уровней). Для статистического расчета, анализа экспериментов и моделирования процесса флотации применен метод поверхности отклика (МПО). Были разработаны четыре квадратичные математические модели для расчетных данных получения Мо и определения его качества. Результаты. Установлено, что вспениватель и коллекторная дозировка являются наиболее влияющими факторами при получении Мо и его качества. В процессе оптимизации максимальные уровни получения Мо и качества были, соответственно, 79.13% и 2.93%. Выявлена следующая оптимальная концентрация для Мо: вспениватель – 78.93 г/т, газолиновая дозировка – 507.70 г/т, pH – 9.7, что подтвержденно моделированием. Научная новизна. Предложен инновационный подход для получения легкого и оптимального способа восстановления и степени извлечения урана до высокого качества. Практическая значимость. Метод поверхностного отклика может эффективно применяться для моделирования процесса флотации с целью определения оптимальных условий достижения максимальной рекуперации и качества при минимальном расходе флотационных реагентов.The financial support of the Jaber Ibn Hayan Research Laboratories, Nuclear Science and Technology Research Institute and Mr. Hasan Sedighi helps and the university of Imam Khomeini (IKIU) is gratefully acknowledged

Distorted Black Holes with Charge

We present new solutions to the Einstein-Maxwell equations representing a class of charged distorted black holes. These solutions are static-axisymmetric and are generalizations of the distorted black hole solutions studied by Geroch and Hartle. Physically, they represent a charged black hole distorted by external matter fields. We discuss the zeroth and first law for these black holes. The first law is proved in two different forms, one motivated by the isolated horizon framework and the other using normalizations at infinity.Comment: 18 pages, LaTe

Non-symmetric trapped surfaces in the Schwarzschild and Vaidya spacetimes

Marginally trapped surfaces (MTSs) are commonly used in numerical relativity to locate black holes. For dynamical black holes, it is not known generally if this procedure is sufficiently reliable. Even for Schwarzschild black holes, Wald and Iyer constructed foliations which come arbitrarily close to the singularity but do not contain any MTSs. In this paper, we review the Wald-Iyer construction, discuss some implications for numerical relativity, and generalize to the well known Vaidya spacetime describing spherically symmetric collapse of null dust. In the Vaidya spacetime, we numerically locate non-spherically symmetric trapped surfaces which extend outside the standard spherically symmetric trapping horizon. This shows that MTSs are common in this spacetime and that the event horizon is the most likely candidate for the boundary of the trapped region.Comment: 4 pages, 3 figures; v2: minor modifications; v3: clarified conclusion

The Ideology of the Politician Discourse in Talk Shows: An Analytical Study

The article aims to explore the ideology of Jordanian politicians discourse in the talk shows, based on Critical Discourse Analysis (CDA) in its ideological aspect, and by applying Van Dijk ideological square. The population has been the program Friendly Fire (NiranSadeeqah) that is broadcast on Amman TV. Seven episodes have been analyzed (of which, their airtime accumulated to (5 hrs. and 51 minutes) that hosted seven Jordanian prime ministers. The analysis categories have been determined based on Van Dijk ideological square; (Emphasizing positive things about Us, emphasizing negative things about Them, De-emphasize negative things about Us, De-emphasizing positive things about Them). The results concluded that the ideology of the Jordanian politicians discourse sought primarily to De-emphasize of the negativity related to the Jordanian politician (36.4%), with (2.07 hrs.) of the seven episodes. At the second rank, the Jordanian politicians discourse focused on emphasizingthe positivity of politician Jordanian (28.7%) with (1.52.30 hrs.). Thirdly, they sought to “Emphasize negative things about others” (19.7%) with (01:06:20 hrs.). Finally, they focused on “De-emphasizing positive things about others (15.2%) with (0:45:30 hrs.)

Pengaruh Partisipasi Anggaran,peran Kuasa Pengguna Anggaran,kejelasan Sasaran Anggaran di Moderasi oleh Budaya Organisasi terhadap Kinerja Aparatur Pemerintah Daerah (Studi Empiris pada Satuan Kerja Perangkat Daerah Kota Pekanbaru)

This Study aims to identify and analyze the effect of budgetery participation,the role of authority of the budget user,clarity of budget goal.organizational culture as moderating variabel on the regional government performance.primary data were collected using a survey of civil servant (PNS) in 32 work units (SKPD) Pekanbaru city government consisting of 96 people head on education public and employment head section and sub-section .the sampling technique used purposive sampling,analysis of the data in this study using multiplelinear regression analysis by using spss version 20.0 The result of this study show that organizational culture as moderating variabel has no effect relation the role of authority of the budget user and the regional government performance

Sam68 is absolutely required for Rev function and HIV-1 production

Sam68 functionally complements for, as well as synergizes with, HIV-1 Rev in Rev response element (RRE)-mediated gene expression and virus production. Furthermore, C-terminal deletion/point mutants of Sam68 (Sam68ΔC/Sam68-P21) exert a transdominant negative phenotype for Rev function and HIV-1 production. However, the relevance of Sam68 in Rev/RRE function is not well defined. To gain more insight into the mechanism of Sam68 in Rev function, we used an RNAi (RNA interference) strategy to create stable Sam68 knockdown HeLa (SSKH) cells. In SSKH cells, Rev failed to activate both RRE-mediated reporter gene [chloramphenicol acetyltransferase (CAT) and/or gag] expressions. Importantly, reduction of Sam68 expression led to a dramatic inhibition of HIV-1 production. Inhibition of the reporter gene expression and HIV production correlated with the failure to export RRE-containing CAT mRNA and unspliced viral mRNAs to the cytoplasm, confirming that SSKH cells are defective for Rev-mediated RNA export. Taken together, these results suggest that Sam68 is involved in Rev-mediated RNA export and is absolutely required for HIV production

The spectrum and prognosis of AIDS-defining illnesses in Cape Town

Objectives. To describe the incidence, spectrum and prognosis of AIDS-defining illnesses (ADI) in patients without access to antiretroviral therapy (ART). Design. Prospective cohort study. Subjects. 1 215 HIV-infected patients attending adult HIV clinics affiliated to the University of Cape Town in the New Somerset and Groote Schuur Hospitals from 1992 to 2000. Main outcome measures. Incidence rate (IR) of ADIs and survival after the ..

Mobile Journalism Skills of Field Reporters of TV Channels

The article aimed to identify the level of mobile journalism skills that field reporters in Jordanian TV channels have. It adopted the survey methodology and applied it to an available sample of (56) reporters. The results showed that self-skills (most important are journalistic sense and observation skills and skills of adapting to smartphones) came first. Professional skills (most important are the skills of communicating with sources, and the skills of transmitting, publishing, and distributing media materials) came second. While technical skills (such as the skill of searching for and verifying information, images and videos, and skills of protecting and securing information) came in the third and final order, being the least of the skills for field reporters. The results also revealed that the most important ethical standards for mobile journalism for reporters are avoiding fabricating journalistic stories, respecting religions, and preserving the confidentiality of sources. Finally, the results concluded that there is a correlation between mobile journalism skills and commitment to ethical standards in the production of media content via mobile