STUDI REGIM ALIRAN FLUIDA DAN PENENTUAN HEAD LOSS AKIBAT GESEKAN PADA INSTALASI PERPIPAAN

Instalasi perpipaan dalam industry merupakan sistem keteknikan memegang perananan penting yang berfungsi untuk mengalirkan  air, minyak dan gas dari satu titik ke titik lain melalui semua komponen yang tercakup didalamnya. Sistem perpipaan terdiri dari pipa lurus, sambungan-sambungan, belokan katup-katup dan peralatan-peralatan instrumentasi yang harus bekerja secara optimal. Regim aliran fluida di dalam berbagai komponen perpipaan memberikan pengaruh terhadap aliran teristimewa pada dua parameter penting yaitu koefesien gesek dan kehilangan head. Tujuan penelitian ini adalah memantau sifat pergerakan fluida dalam rezim laminar dan turbulen dan menentukan nilai head loss sebagai fungsi debit dalam rezim laminar dan turbulen. Penelitian dilakukan pada pipa lurus berdiamater 4 inci dengan panjang total 10 meter, diameter 4 inci dengan satu belokan 90o. Penentuan hubungan kerugian head terhadap debit dilakukan melalui simulasi hidrodinamika, dimana kecepatan aliran divariasi dari 0,02 - 0,1 m/s, sesuai dengan debit Q = 10-52 liter/menit. Variasi kecepatan ini melewati regim aliran laminar dan turbulen yang diukur pada 4 penampang pada pipa lurus dan elbow. Hasil yang diperoleh menunjukan bahwa profil aliran pada setiap penampang berbeda-bada untuk nilai debit Q yang sama. Pada setiap penampang dengan variasi nilai debit Q, karakter nilai kerugian head meningkat dengan meningkatnya debit aliran Q dengan nilai berbeda pada setiap penampang, namun trend perubahannya mirip. Kondisi laminar terjadi pada Q <34 lit/menit dengan kerugian head hdl < 0,74x10-3 m,  transisi terjadi pada Q=34-36 lit/menit, dengan hdl = (0,74 -0,68)x10-3 m dan turbulen sepenuhnya pada Q>36 lit/menit dengan hdl > 0,74x10-3 m. Hal ini menujukan bahwa pada elbow atau belokan, aliran akan menjadi turbulen walaupun pada kecepatan yang rendah

18F-fluorodeoxyglucose positron emission tomography-positive sarcoidosis after chemoradiotherapy for Hodgkin’s disease: a case report

<p>Abstract</p> <p>Introduction</p> <p>The occurrence of granulomatous disease in the setting of Hodgkin's disease is rare; however, when it occurs it can pose significant clinical and diagnostic challenges for physicians treating these patients.</p> <p>Case presentation</p> <p>We report the case of a 33-year-old Caucasian woman of Mediterranean descent with newly diagnosed ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET)/computed tomography (CT) scan-positive, early-stage Hodgkin's disease involving the cervical nodes who, despite having an excellent clinical response to chemotherapy, had a persistent ¹⁸F-FDG PET scan-positive study, which was suggestive of residual or progressive disease. A subsequent biopsy of her post-chemotherapy PET-positive nodes demonstrated sarcoidosis with no evidence of Hodgkin's disease.</p> <p>Conclusion</p> <p>This case highlights the fact that abnormalities observed on posttherapy PET/CT scans in patients with Hodgkin's disease are not always due to residual or progressive disease. An association between Hodgkin's disease and/or its treatment with an increased incidence of granulomatous disease appears to exist. Certain patterns of ¹⁸F-FDG uptake observed on PET/CT scans may suggest other pathologies, such as granulomatous inflammation, and because of the significant differences in prognosis and management, clinicians should maintain a low threshold of confidence for basing their diagnosis on histopathological evaluations when PET/CT results appear to be incongruent with the patient's clinical response.</p

A Self-Consistent Model for Positronium Formation from Helium Atoms

The differential and total cross sections for electron capture by positrons from helium atoms are calculated using a first-order distorted wave theory satisfying the Coulomb boundary conditions. In this formalism a parametric potential is used to describe the electron screening in a consistent and realistic manner. The present procedure is self consistent because (i) it satisfies the correct boundary conditions and post-prior symmetry, and (ii) the potential and the electron binding energies appearing in the transition amplitude are consistent with the wave functions describing the collision system. The results are compared with the other theories and with the available experimental measurements. At the considered range of collision energies, the results agree reasonably well with recent experiments and theories. [Note: This paper will be published on volume 42 of the Brazilian Journal of Physics

An Equation of State of a Carbon-Fibre Epoxy Composite under Shock Loading

An anisotropic equation of state (EOS) is proposed for the accurate extrapolation of high-pressure shock Hugoniot (anisotropic and isotropic) states to other thermodynamic (anisotropic and isotropic) states for a shocked carbon-fibre epoxy composite (CFC) of any symmetry. The proposed EOS, using a generalised decomposition of a stress tensor [Int. J. Plasticity \textbf{24}, 140 (2008)], represents a mathematical and physical generalisation of the Mie-Gr\"{u}neisen EOS for isotropic material and reduces to this equation in the limit of isotropy. Although a linear relation between the generalised anisotropic bulk shock velocity $U^{A}_{s}$ and particle velocity $u_{p}$ was adequate in the through-thickness orientation, damage softening process produces discontinuities both in value and slope in the $U^{A}_{s}$-$u_{p}$ relation. Therefore, the two-wave structure (non-linear anisotropic and isotropic elastic waves) that accompanies damage softening process was proposed for describing CFC behaviour under shock loading. The linear relationship $U^{A}_{s}$-$u_{p}$ over the range of measurements corresponding to non-linear anisotropic elastic wave shows a value of $c^{A}_{0}$ (the intercept of the $U^{A}_{s}$-$u_{p}$ curve) that is in the range between first and second generalised anisotropic bulk speed of sound [Eur. Phys. J. B \textbf{64}, 159 (2008)]. An analytical calculation showed that Hugoniot Stress Levels (HELs) in different directions for a CFC composite subject to the two-wave structure (non-linear anisotropic elastic and isotropic elastic waves) agree with experimental measurements at low and at high shock intensities. The results are presented, discussed and future studies are outlined.Comment: 12 pages, 9 figure

Effect of maternal panic disorder on mother-child interaction and relation to child anxiety and child self-efficacy

To determine whether mothers with panic disorder with or without agoraphobia interacted differently with their children than normal control mothers, 86 mothers and their adolescents (aged between 13 and 23 years) were observed during a structured play situation. Maternal as well as adolescent anxiety status was assessed according to a structured diagnostic interview. Results showed that mothers with panic disorder/agoraphobia showed more verbal control, were more criticizing and less sensitive during mother-child interaction than mothers without current mental disorders. Moreover, more conflicts were observed between mother and child dyadic interactions when the mother suffered from panic disorder. The comparison of parenting behaviors among anxious and non-anxious children did not reveal any significant differences. These findings support an association between parental over-control and rejection and maternal but not child anxiety and suggest that particularly mother anxiety status is an important determinant of parenting behavior. Finally, an association was found between children’s perceived self-efficacy, parental control and child anxiety symptoms

Cardiac safety of dual anti-HER2 blockade with pertuzumab plus trastuzumab in early HER2-positive breast cancer in the APHINITY trial.

BACKGROUND Trastuzumab increases the incidence of cardiac events (CEs) in patients with breast cancer (BC). Dual blockade with pertuzumab (P) and trastuzumab (T) improves BC outcomes and is the standard of care for high-risk human epidermal growth factor receptor 2 (HER2)-positive early BC patients. We analyzed the cardiac safety of P and T in the phase III APHINITY trial. PATIENTS AND METHODS Left ventricular ejection fraction (LVEF) ≥ 55% was required at study entry. LVEF assessment was carried out every 3 months during treatment, every 6 months up to month 36, and yearly up to 10 years. Primary CE was defined as heart failure class III/IV and a significant decrease in LVEF (defined as ≥10% from baseline and to <50%), or cardiac death. Secondary CE was defined as a confirmed significant decrease in LVEF, or CEs confirmed by the cardiac advisory board. RESULTS The safety analysis population consisted of 4769 patients. With 74 months of median follow-up, CEs were observed in 159 patients (3.3%): 83 (3.5%) in P + T and 76 (3.2%) in T arms, respectively. Most CEs occurred during anti-HER2 therapy (123; 77.4%) and were asymptomatic or mildly symptomatic decreases in LVEF (133; 83.6%). There were two cardiac deaths in each arm (0.1%). Cardiac risk factors indicated were age > 65 years, body mass index ≥ 25 kg/m2, baseline LVEF between 55% and <60%, and use of an anthracycline-containing chemotherapy regimen. Acute recovery from a CE based on subsequent LVEF values was observed in 127/155 patients (81.9%). CONCLUSIONS Dual blockade with P + T does not increase the risk of CEs compared with T alone. The use of anthracycline-based chemotherapy increases the risk of a CE; hence, non-anthracycline chemotherapy may be considered, particularly in patients with cardiovascular risk factors

The strategic calculus of terrorism: Substitution and competition in the Israel—Palestine conflict

Previous work on the dynamics of conflicts where we see terrorism has tended to focus on whether we see shifts in attack mode following government countermeasures. We contend that many factors other than counterinsurgency can influence whether groups resort to terrorism, including competition between groups, as well as their relationship to public opinion and other political events. Hence, understanding terrorist tactics in prolonged conflicts with multiple actors requires us to consider a more general framework of innovation, imitation, competition and dependence between actors. We use disaggregated data on terrorist attacks, counterterrorism and public opinion in the Israel—Palestine conflict to jointly evaluate predictions derived from several conventional theories of strategic behaviour. We find that the strategic calculus of Palestinian groups is complex and cannot be treated as time invariant. Our results suggest that factors such as the degree of public support, inter-group competition, the anticipation of countermeasures and non-trivial non-violent payoffs have an observable effect on the strategic behaviour of the Palestinian groups, and that structural relationships are often far from constant over time. </jats:p

The Early Husserl on Typicality

This paper presents and evaluates the early Husserl’s account of typicality. In the Logical Investigations, Husserl holds that the meaning of ordinary language (common) names is sensitive to typicality: this meaning depends on typical examples which vary in different contexts and are more or less similar to one another. This seems to entail that meanings, which according to Husserl are concepts, are “fluctuating” (schwankend) and vague. Prima facie, such a claim contravenes his theory of ideal meanings, or concepts, which are “fixed” (fest) and sharp. However, Husserl wants to save this theory. He claims that the fluctuation and vagueness in question are not to be found in the meaning itself, or the concept, but rather derive from the act of meaning. Thus, he apparently manages to make room for typicality in ordinary language while accepting only fixed and sharp meanings. After presenting Husserl’s theory, I evaluate it and ask whether he will still be committed, despite his own claims, to accepting prototype concepts to account for typicality in ordinary language