Prediksi Kedalaman Terbentuknya Wax Pada Sumur X Lapangan Y

Ketika temperatur crude oil berkurang, komponen-komponen berat seperti paraffin/wax (C18 – C60) akan terpresipitasi dan mengendap pada dinding pipa. Pengendapan wax dapat menyebabkan diameter internal pipa berkurang dan pipa tersumbat. Laju produksi yang rendah dapat mempengaruhi terjadinya deposit wax karena waktu tinggal (residence time) minyak yang lama di pipa. Residence time minyak yang lama, menyebabkan adanya heat loss dari fluida, sehingga menurunkan temperatur minyak saat mengalir. Penelitian ini dilakukan dengan tujuan untuk memprediksi kedalaman terbentuknya wax pada sumur X. Untuk mengetahui kedalaman terbentuknya wax pada sumur X, yaitu dengan memplot hasil prediksi distribusi tekanan dan temperatur per kedalaman kedalam kurva wax deposition envelope. Fase wax pada sumur X akan muncul pada temperatur 131 °F dan tekanan 343 psi di kedalaman 300 ft dari kepala sumur dan pada saat tekanan statis reservoir mencapai 1752 psi

Komunikasi Pendek* Studi Floristik Jenis-jenis Anggrek (Orchidaceae) Di Taman Nasional Gunung Halimun, Jawabarat

Lokasi Taman Nasional Gunung Halimun secara administratif termasuk dalam tiga wilayah Kabupaten, yaitu Bogor, Sukabumi dan Lebak.Kawasan ini diresmikan sebagai Taman Nasional pada tahun 1992 yang meliputi luasan 40.000 ha.(Anonim. 1999.Gunung Halimun National Park Mesh Map. Biodiversity Conservation Project. Bogor. 53 pp.). Taman Nasional Gunung Halimun terbagi dalam sembilan daerah kerja (Resort). Lima resort di antaranya, yaitu kawasan resort Citorek,Cikelat, Kabandungan, Cisangku dan Cigudeg telah dikunjungi dan diamati keragaman jenis anggreknya. Tujuan penelitian ini adalah untuk mengetahui keragaman jenis anggrek dan mengevaluasi status populasinya di alam

Optimal Monthly Reservoir Operation Rules for Hydropower Generation Derived with SVR-NSGAII

A novel tool is proposed that couples the nondominated sorting genetic algorithm (NSGAII) with support vector regression (SVR) and nonlinear programming (NLP) to optimize monthly operation rules for hydropower generation. The SVR-NSGAII is applied to calculate the optimized release for hydropower generation by minimizing (1) the error committed by the SVR in extracting the optimized operation rule, and (2) the number of input variables used as predictors (the parsimony feature) in a regression model. The SVR calculates the optimized reservoir release for hydropower generation based on input variables and parameters values that are found by the NSGAII. An evaluation of results obtained for the Karoon-4 reservoir of Iran indicates that the SVR-NSGAII is well suited to calculate the optimal hydropower reservoir operation rule in real time with approximately 90% accuracy

Risk of Pseudotumor Cerebri Syndrome (PTCS) with hormonal contraceptive use

Background: Hormonal contraceptives (HC), one of the most prescribed classes of medication in women, have been linked with pseudotumor cerebri syndrome (PTCS). To date, no large epidemiologic study has examined this association.Methods: A case-control study using the IMS LifeLink Pharmetrics Plus database was conducted. Cases had an ICD-9-CM code for benign intracranial hypertension as well as a procedural code for a CT or MRI and a code for lumbar puncture procedure within 15 days of the PTCS code. Controls were selected from the cohort using density-based sampling.Results: From a cohort of 9,053,240 subjects, there were 288 cases of PTCS corresponding to 2,880 controls. The adjusted RRs for two or more prescriptions of oral combined contraceptive was 0.62 (95% confidence interval 0.39-0.99). RRs for overall HC use was 0.91 (95% CI 0.39-2.12) for one prescription of HCs and 0.69 (95% CI 0.45-1.05) for two or more prescriptions. The RRs for one and two or more prescriptions of progestin only HCs were 0.75 (95% CI 0.08-7.46) and 1.06 (95% CI 0.42-2.69), respectively.Conclusions: Overall HC use does not have a significant effect on incidence of PTCS, however harm associated with progestin-only contraceptives cannot be excluded