CVD of silicon carbide on structural fibers: Microstructure and composition

Structural fibers are currently being considered as reinforcements for intermetallic and ceramic materials. Some of these fibers, however, are easily degraded in a high temperature oxidative environment. Therefore, coatings are needed to protect the fibers from environmental attack. Silicon carbide (SiC) was chemically vapor deposited (CVD) on Textron's SCS6 fibers. Fiber temperatures ranging from 1350 to 1500 C were studied. Silane (SiH4) and propane (C2H8) were used for the source gases and different concentrations of these source gases were studied. Deposition rates were determined for each group of fibers at different temperatures. Less variation in deposition rates were observed for the dilute source gas experiments than the concentrated source gas experiments. A careful analysis was performed on the stoichiometry of the CVD SiC coating using electron microprobe. Microstructures for the different conditions were compared. At 1350 C, the microstructures were similar; however, at higher temperatures, the microstructure for the more concentrated source gas group were porous and columnar in comparison to the cross sections taken from the same area for the dilute source gas group

Introducing a Manipulated System of Drainage Basins of a Developing Countries

As a natural open system, in a drainage basin, there is water flow and balanced channel characteristics. In a manipulated channel system, however, according to Mrowka (1974) and Schumm (1977), the water flow is made under control that induces dynamics in channel characteristics. In this paper, attempt is made to uncover how channel project is caused, nature of the new forms of channel cross-sectional area, shape, sinuosity, and gradient, as well as flood-plain characteristics. It also covers the peculiar transformation evolved as drainage basin system is changed to channel project. Consequently in the paper, two tasks involved were explained. These are significant channel re-construction, and redirection of stream flow as relates to developing water terrace in the savanna zone of Nigeria with the increased channel project dated back 1970s (Olofin, 1980). Specifically, the paper drew considered the physical characteristics of the natural channel of River Suka in North Central Nigeria and the manipulated system or the new face of the drainage basin project of the Kano River, Nigeria used to structure the Tiga dam that involved downstream channel adjustments Keywords: drainage basin, channel, river, dam, downstrea

Optimization of Water Treatment Parameters using Processed Moringa oleifera As a Natural Coagulant for Low Turbidity Water

Moringa oleifera is a natural coagulant which can be used for water treatment in tropical developing countries. This study presents the results of production of natural coagulant from processed Moringa oleifera with simple technique (oil extraction, salt extraction, and microfiltration with 0.2 μm). The optimization study on physical factors was carried out for coagulation-flocculation process. Low initial turbidity water samples (synthetic and river water) were used with turbidity less than 50 Nephelometric Turbidity Units (NTU). The response surface methodology (RSM) was used, and the analysis of variance (ANOVA) was performed to validate the developed regression model. The residual turbidity obtained was 4.514 NTU for synthetic water and 1.598 NTU for river water by applying the optimum conditions of 40 rpm (low speed), mixing time of 41 minutes, and Moringa oleifera dosage of 0.75 mg/L

3-D CFD transient simulation of transesterification in stirred tank reactor

A transient CFD simulation was successfully carried out for waste cooking oil (WCO)transesterification in a stirred tank reactor (STR). In this work, a multi-species reaction model was simplified to simulate the reactive flow in an STR using in a multiple reference frame (MRF)approach. Average velocity fields in the STR, by a mixed flow impeller were taken using a 2-D PIV technique to calculate the turbulence and dissipation energy statistically for the numerical model. The thermo-physical properties of the reacting species were incorporated as user defined function (UDF) to implement the reaction in ANSYS FluentTM. Reaction/ flow coupling was achieved using the eddy dissipation model. The biodiesel yield predictions were fairly comparable with the experimental data. Time steps of the model are important aspects that primarily affect the solutions of the simulation

Специфика организации транспортной службы предприятия

В данной статье были рассмотрены проблемы организации транспортной службы предприятия. Актуальность темы исследования обусловлена, тем, что любую готовую продукцию необходимо транспортировать, в связи с этим были рассмотрены общие характеристики транспортной службы предприятия, сделаны выводы, позволяющие повысить эффективность работы транспортного цеха предприятия за счет повышения качества надежности внешних и внутрипроизводственных перевозок, что обеспечит повышение конкурентоспособности предприятия в целом

Spin Liquid Phases in 2D Frustrated XY Model

In this paper we consider the $J_1-J_2-J_3$ classical and quantum 2D XY model. Spin wave calculations show that a spin liquid phase still exists in the quantum case as for Heisenberg models. We formulate a semiclassical approach of these models based on spin wave action and use a variational method to study the role played by vortices. Liquid and crystal phases of vortex could emerge in this description. These phases seem to be directly correlated with the spin liquid one and to its crystalline interpretation.Comment: 16 pages, Latex, 4 figures. To be published in Phys. Rev.

Hydatid cyst disease of the lung as an unusual cause of massive hemoptysis: a case report

<p>Abstract</p> <p>Introduction</p> <p>Echinococcosis and/or hydatidosis is one of the most important zoonotic diseases in the world. In Turkey, echinococcosis is an endemic disease, however, hydatid disease of the lung is uncommon and usually caused by <it>Echinococcus granulosus</it>.</p> <p>Case presentation</p> <p>In this report we describe a 17-year-old male patient who presented with massive hemoptysis due to hydatid disease of the lung.</p> <p>Conclusion</p> <p>Although it is one of the less common causes of massive hemoptysis, hydatid disease of the lung requires greater attention in countries, such as Turkey, in which hydatid cyst disease is common.</p

Implementation of a Digitally Enabled Care Pathway (Part 2): Qualitative Analysis of Experiences of Health Care Professionals.

BACKGROUND: One reason for the introduction of digital technologies into health care has been to try to improve safety and patient outcomes by providing real-time access to patient data and enhancing communication among health care professionals. However, the adoption of such technologies into clinical pathways has been less examined, and the impacts on users and the broader health system are poorly understood. We sought to address this by studying the impacts of introducing a digitally enabled care pathway for patients with acute kidney injury (AKI) at a tertiary referral hospital in the United Kingdom. A dedicated clinical response team-comprising existing nephrology and patient-at-risk and resuscitation teams-received AKI alerts in real time via Streams, a mobile app. Here, we present a qualitative evaluation of the experiences of users and other health care professionals whose work was affected by the implementation of the care pathway. OBJECTIVE: The aim of this study was to qualitatively evaluate the impact of mobile results viewing and automated alerting as part of a digitally enabled care pathway on the working practices of users and their interprofessional relationships. METHODS: A total of 19 semistructured interviews were conducted with members of the AKI response team and clinicians with whom they interacted across the hospital. Interviews were analyzed using inductive and deductive thematic analysis. RESULTS: The digitally enabled care pathway improved access to patient information and expedited early specialist care. Opportunities were identified for more constructive planning of end-of-life care due to the earlier detection and alerting of deterioration. However, the shift toward early detection also highlighted resource constraints and some clinical uncertainty about the value of intervening at this stage. The real-time availability of information altered communication flows within and between clinical teams and across professional groups. CONCLUSIONS: Digital technologies allow early detection of adverse events and of patients at risk of deterioration, with the potential to improve outcomes. They may also increase the efficiency of health care professionals' working practices. However, when planning and implementing digital information innovations in health care, the following factors should also be considered: the provision of clinical training to effectively manage early detection, resources to cope with additional workload, support to manage perceived information overload, and the optimization of algorithms to minimize unnecessary alerts