Effect of V-shaped Ribs on Internal Cooling of Gas Turbine Blades

Thermal efficiency and power output of gas turbines increase with increasing turbine rotor inlet temperature. The rotor inlet temperatures in most gas turbines are far higher than the melting point of the blade material. Hence the turbine blades need to be cooled. In this work, simulations were carried out with the leading edge of gas turbine blade being internally cooled by coolant passages with V-shaped ribs at angles of 30°, 45° or 60° and at three aspect ratios (1:1, 1:2 and 2:3). The trailing edge of the blade was cooled by cylindrical and triangular pin-fin perforations in staggered and inline arrangements. Numerical analyses were carried out for each configuration of the cooling passages. The best cooling passages for leading edge and trailing edge were deduced by comparing the results of these analyses. It was found that using V-shaped ribs and fins induces a swirling flow, which in turn increases the velocity gradient and hence produces an improvement in heat transfer. The results show that under real time flow conditions, the application of V-shaped ribs and pin-fin perforations is a very promising technique for improving blade life

HPLC Method for Determination of p-coumaric acid from the Medicinal Herb Leptadinia reticulata

The aim of present study was to develop and validate a simple, precise and rapid HPLC method for the quantification of p-coumaric acid in Leptadinia reticulata extractst. The analysis was performed by reverse-phase chromatography on an phenomenex C18 columns with isocratic elution of Methanol and 0.8%-Formic acid in water (6:4) at a flow rate of 1.0mL/min, a column temperature of 35°C, photodiode array detector detection at 326 nm. The method validated in terms of linearity accuracy precision LOD, LOQ and stability. The herb Leptidinia reticulata contains 0.17% p-coumaric acid. The linear range of method was 0.25-50µg/ml with correlation coefficient of 0.9993, the recovery was 98-99.4% and the relative standard deviation is 0.98 % (n=6). The developed method was found to be a relatively simple, precise and reproducible for the quantification of p-coumaric acid. The method does not employ any derivatization procedure and can be used as a quality control tool for the routine analysis of    p-coumaric acid from an herb Leptadinia reticulata

The contributions of focused attention and open monitoring in mindfulness-based cognitive therapy for affective disturbances: A 3-armed randomized dismantling trial

OBJECTIVE: Mindfulness-based cognitive therapy (MBCT) includes a combination of focused attention (FA) and open monitoring (OM) meditation practices. The aim of this study was to assess both short- and long-term between- and within-group differences in affective disturbance among FA, OM and their combination (MBCT) in the context of a randomized controlled trial. METHOD: One hundred and four participants with mild to severe depression and anxiety were randomized into one of three 8-week interventions: MBCT (n = 32), FA (n = 36) and OM (n = 36). Outcome measures included the Inventory of Depressive Symptomatology (IDS), and the Depression Anxiety Stress Scales (DASS). Mixed effects regression models were used to assess differential treatment effects during treatment, post-treatment (8 weeks) and long-term (20 weeks). The Reliable Change Index (RCI) was used to translate statistical findings into clinically meaningful improvements or deteriorations. RESULTS: All treatments demonstrated medium to large improvements (ds = 0.42-1.65) for almost all outcomes. While all treatments were largely comparable in their effects at post-treatment (week 8), the treatments showed meaningful differences in rapidity of response and pattern of deteriorations. FA showed the fastest rate of improvement and the fewest deteriorations on stress, anxiety and depression during treatment, but a loss of treatment-related gains and lasting deteriorations in depression at week 20. OM showed the slowest rate of improvement and lost treatment-related gains for anxiety, resulting in higher anxiety in OM at week 20 than MBCT (d = 0.40) and FA (d = 0.36), though these differences did not reach statistical significance after correcting for multiple comparisons (p\u27s = .06). MBCT and OM showed deteriorations in stress, anxiety and depression at multiple timepoints during treatment, with lasting deteriorations in stress and depression. MBCT showed the most favorable pattern for long-term treatment of depression. CONCLUSIONS: FA, OM and MBCT show different patterns of response for different dimensions of affective disturbance. TRIAL REGISTRATION: This trial is registered at (v NCT01831362); www.clinicaltrials.gov

Preparation of Microcrystals of Piroxicam Monohydrate by Antisolvent Precipitation via Microfabricated Metallic Membranes with Ordered Pore Arrays

Microcrystals of piroxicam (PRX) monohydrate with a narrow size distribution were prepared from acetone/PRX solutions by antisolvent crystallization via metallic membranes with ordered pore arrays. Crystallization was achieved by controlled addition of the feed solution through the membrane pores into a well-stirred antisolvent. A complete transformation of an anhydrous form I into a monohydrate form of PRX was confirmed by Raman spectroscopy and differential scanning calorimetry. The size of the crystals was 7–34 μm and was controlled by the PRX concentration in the feed solution (15–25 g L¯¹), antisolvent/solvent volume ratio (5–30), and type of antisolvent (Milli-Q water or 0.1–0.5 wt % aqueous solutions of hydroxypropyl methyl cellulose (HPMC), poly(vinyl alcohol) or Pluronic P-123). The smallest crystals were obtained by injecting 25 g L¯¹ PRX solution through a stainless-steel membrane with a pore size of 10 μm into a 0.06 wt % HPMC solution stirred at 1500 rpm using an antisolvent/solvent ratio of 20. HPMC provided better steric stabilization of microcrystals against agglomeration than poly(vinyl alcohol) and Pluronic P-123, due to hydrogen bonding interactions with PRX and water. A continuous production of large PRX monohydrate microcrystals with a volume-weighted mean diameter above 75 μm was achieved in a continuous stirred membrane crystallizer. Rapid pouring of Milli-Q water into the feed solution resulted in a mixture of highly polydispersed prism-shaped and needle-shaped crystals

Effectiveness of post-partum family planning interventions on contraceptive use and method mix at 1 year after childbirth in Kinshasa, DR Congo (Yam Daabo): a single-blind, cluster-randomised controlled trial.

BACKGROUND:In rural Burkina Faso, a package of six low-technology, post-partum contraceptive interventions (ie, refresher training for providers, a counselling tool, supportive supervision, daily availability of contraceptive services, client appointment cards, and invitation letters to attend appointments for partners), aimed at strengthening existing primary health-care services and enhancing demand for them, doubled the use of modern contraceptives at 12 months post partum (ie, 55% uptake in intervention recipients vs 29% in routine-care users). This study assessed the effect of a similar package but in urban settings of Kinshasa province, Democratic Republic of the Congo, in an effort to reduce the unmet need for post-partum family planning. METHODS:Yam Daabo was a multi-intervention, single-blinded, cluster-randomised controlled trial done in six primary health-care centres (clusters) in Kinshasa. Centres were randomly allocated to receive the six-component intervention or standard antenatal and postnatal care in matched pairs (1:1) on the basis of number of monthly births, the ratio of health workers per population in the health zone, and the urban and suburban settings. Only data analysts could be masked to cluster allocation. Health-care facilities were eligible if they provided a continuum of antenatal, delivery, and postnatal care, were well stocked with contraceptives, and were situated close to the main study centre. All pregnant women presenting to the six centres were eligible if they were in their third pregnancy trimester and had no counterindications to deliver in the facility. The main outcome was prevalence of use of modern contraceptives at 12 months after delivery. Analysis was by modified intention-to-treat using generalised linear mixed models or Fisher's exact test for small groups. Prevalence ratios were adjusted for cluster effects and baseline characteristics. This study was registered with the Pan-African Clinical Trials Registry (PACTR201609001784334). FINDINGS:From July 1, 2016, to Feb 2, 2017, eight of 52 clinics assessed for eligibility met the criteria and were randomised. Of 690 women approached, 576 (83%) women were enrolled: 286 in the four intervention clusters and 290 in the four control clusters. Of them, 519 (90%) completed the 12-month study exit interview (252 in the intervention group and 267 in the control group) and were included in the intention-to-treat analysis. At 12 months, 115 (46%) of 252 women in the intervention group and 94 (35%) of 267 in the control group were using modern contraceptives (adjusted prevalence ratio [PR] 1·58, 95% CI 0·74-3·38), with significant differences in the use of contraceptive implants (22% vs 6%; adjusted PR 4·36, 95% CI 1·96-9·70), but without difference in the use of short-acting contraceptives (23% vs 28%; 0·92, 0·29-2·98) and non-modern or inappropriate methods (7% vs 18%; 0·45, 0·13-1·54). There were no serious adverse events or maternal deaths related to the study. INTERPRETATION:The Yam Daabo intervention package did not have a significant effect on the overall use of effective modern contraceptives but significantly increased implant use in women post partum who live in urban settings in Kinshasa up to a year after childbirth. However, interferences from external family planning initiatives in the control group might have diminished differences between the services received. Such an intervention could be potentially relevant in similar contexts in DR Congo and other countries. FUNDING:Government of France; UNDP/UNFPA/UNICEF/WHO/World Bank Special Programme of Research, Development and Research Training in Human Reproduction

Evidence for structural and electronic instabilities at intermediate temperatures in κ\kappa-(BEDT-TTF)2_{2}X for X=Cu[N(CN)2_{2}]Cl, Cu[N(CN)2_{2}]Br and Cu(NCS)2_{2}: Implications for the phase diagram of these quasi-2D organic superconductors

We present high-resolution measurements of the coefficient of thermal expansion $\alpha (T)=\partial \ln l(T)/\partial T$ of the quasi-twodimensional (quasi-2D) salts $\kappa$-(BEDT-TTF)$_2$X with X = Cu(NCS)$_2$, Cu[N(CN)$_2$]Br and Cu[N(CN)$_2$]Cl. At intermediate temperatures (B), distinct anomalies reminiscent of second-order phase transitions have been found at $T^\ast = 38$ K and 45 K for the superconducting X = Cu(NCS)$_2$ and Cu[N(CN)$_2$]Br salts, respectively. Most interestingly, we find that the signs of the uniaxial pressure coefficients of $T^\ast$ are strictly anticorrelated with those of $T_c$. We propose that $T^\ast$ marks the transition to a spin-density-wave (SDW) state forming on minor, quasi-1D parts of the Fermi surface. Our results are compatible with two competing order parameters that form on disjunct portions of the Fermi surface. At elevated temperatures (C), all compounds show $\alpha (T)$ anomalies that can be identified with a kinetic, glass-like transition where, below a characteristic temperature $T_g$, disorder in the orientational degrees of freedom of the terminal ethylene groups becomes frozen in. We argue that the degree of disorder increases on going from the X = Cu(NCS)$_2$ to Cu[N(CN)$_2$]Br and the Cu[N(CN)$_2$]Cl salt. Our results provide a natural explanation for the unusual time- and cooling-rate dependencies of the ground-state properties in the hydrogenated and deuterated Cu[N(CN)$_2$]Br salts reported in the literature.Comment: 22 pages, 7 figure

Substitution Effect by Deuterated Donors on Superconductivity in κ\kappa-(BEDT-TTF)2_2Cu[N(CN)2_2]Br

We investigate the superconductivity in the deuterated BEDT-TTF molecular substitution system $\kappa$-[(h8-BEDT-TTF)$_{1-x}$(d8-BEDT-TTF)$_x$]$_2$Cu[N(CN)$_2$]Br, where h8 and d8 denote fully hydrogenated and deuterated molecules, respectively. Systematic and wide range ($x$ = 0 -- 1) substitution can control chemical pressure finely near the Mott boundary, which results in the modification of the superconductivity. After cooling slowly, the increase of $T_{\textrm{c}}$ observed up to $x \sim$ 0.1 is evidently caused by the chemical pressure effect. Neither reduction of $T_{\textrm{c}}$ nor suppression of superconducting volume fraction is found below $x \sim$ 0.5. This demonstrates that the effect of disorder by substitution is negligible in the present system. With further increase of $x$, both $T_{\textrm{c}}$ and superconducting volume fraction start to decrease toward the values in $x$ = 1.Comment: J. Phys. Soc. Jp

Participatory action research to identify a package of interventions to promote postpartum family planning in Burkina Faso and the Democratic Republic of Congo

© 2018 The Author(s). Background: The YAM DAABO study ("your choice" in Mooré) takes place in Burkina Faso and the Democratic Republic of Congo. It has the objective to identify a package of postpartum family planning (PPFP) interventions to strengthen primary healthcare services and determine its effectiveness on contraceptive uptake during the first year postpartum. This article presents the process of identifying the PPFP interventions and its detailed contents. Methods: Based on participatory action research principles, we adopted an inclusive process with two complementary approaches: a bottom-up formative approach and a circular reflective approach, both of which involved a wide range of stakeholders. For the bottom-up component, we worked in each country in three formative sites and used qualitative methods to identify barriers and catalysts to PPFP uptake. The results informed the package design which occurred during the circular reflective approach - a research workshop gathering service providers, members of both country research teams, and the WHO coordination team. Results: As barriers and catalysts were found to be similar in both countries and with the view to scaling up our strategy to other comparable settings, we identified a common package of six low-cost, low-technology, and easily-scalable interventions that addressed the main service delivery obstacles related to PPFP: (1) refresher training of service providers, (2) regularly scheduled and strengthened supportive supervision of service providers, (3) enhanced availability of services 7 days a week, (4) a counseling tool, (5) appointment cards for women, and (6) invitation letters for partners. Conclusions: Our research strategy assumes that postpartum contraceptive uptake can be increased by supporting providers, enhancing the availability of services, and engaging women and their partners. The package does not promote any modern contraceptive method over another but prioritizes the importance of women's right to information and choice regarding postpartum fertility options. The effectiveness of the package will be studied in the experimental phase. If found to be effective, this intervention package may be relevant to and scalable in other parts of Burkina Faso and the DRC, and possibly other Sub-Saharan countries