Thermal performance and pressure drop of different pin-fin geometries

The purpose of this study is to show the performance of hexagonal, square and cylindrical pin-fin arrays in improving heat transfer. In the present study, the thermal performance and pressure drop of the pin-fin heat exchanger are studied. The heat exchanger consists of cylindrical, hexagonal and square pin-fins. These types of pin-fins are capable of producing beneficial effects in transport enhancement and flow control. The pin-fins were arranged in an in-line manner. The relative longitudinal pitch SL/D=2 , and the relative transverse pitch were kept constant ST/D=2 . Air and water are used as working fluids in shell side and tube side, respectively. The inlet temperatures of air are between 50 and 90° C. The cold water entering the heat exchanger at the inner channel flows across the fin and flows out at the inner channel. Such pin-fins show potential for enhancing the heat transfer rate in pin-fin cross flow heat exchanger

Effects of Topical Ozone Application on Outcomes after Accelerated Corneal Collagen Cross-linking: An Experimental Study

Purpose: Ozone is a trioxygen molecule that spontaneously degrades into oxygen and oxygen free radicals. This study was designed to assess the effects of topical ozone application on outcomes after corneal collagen cross-linking (CXL). Methods: Enucleated fresh cadaver yearling sheep eyes (n = 28) were divided into five groups: control (C, n = 6), sham (S, n = 6), ozone only (Z, n = 6), CXL only (X, n = 5), and Ozone + CXL (ZX, n = 5). In all groups, except C, the epithelial layer was removed. In group Z, 20 μg/mL liquid ozone was topically applied. In group X, CXL was performed in the accelerated pulse mode. In group ZX, both CXL and ozone were applied. Post-interventional oxygen levels were determined and corneal confocal microscopy and optical coherence tomography were performed. Corneas were evaluated using light and electron microscopy. Results: Pre-interventional central corneal thickness (CCT) was highest in the control group and considerably similar in the remaining groups (P = 0.006). Pre- and post-interventional CCT were significantly different in the ozonated groups (Z and ZX) (P = 0.028; P = 0.043). Demarcation line depths were similar in groups Z, X, and ZX (P = 0.343). Increased stromal tissue reflectivity was observed in groups Z, X, and ZX. Oxygen levels were higher in the ozonated groups (Z and ZX) (P = 0.006), and caspase activity was higher in the CXL groups (X and ZX) (P = 0.028) as compared to the other groups. Group ZX showed tighter, more regular, and parallel fibrils. Conclusion: Ozone increases corneal stromal oxygenation which can probably augment the effect of CXL. Future studies should investigate the safety and feasibility of ozone application during CXL

Effect of curing conditions on the engineering properties of self-compacting concrete

25-29The paper reports an experimental study investigating the influence of curing conditions on the engineering properties of self-compacting concretes (SCC). Portland cement (PC) concrete and two types of SCC, i.e., SCC-I with fly ash and SCC-II with silica fume, specimens are prepared and cured in three different curing conditions, namely standard 20°C water, sealed and air cured for the periods of 3, 7, 14 and 28 days. At the end of each curing period, compressive and tensile strength and ultrasonic pulse velocity (UPV) values are determined. The results showed that water cured specimens always give the highest values followed by those cured as sealed and in air irrespective of type and age of concrete and test methods. For both compressive and tensile strength tests, the SCC-II gives the highest values followed by SCC-I and then PC concrete for all curing periods and conditions. Whilst, the UPV results showed that the highest values are obtained from the SCC-I and then from the PC concrete and SCC-II for all curing conditions

Capillary water absorption of self-compacting concrete under different curing conditions

365-372This paper reports an experimental study carried out to investigate the influence of addition of pozzolanic materials and curing regimes on the mechanical properties and the capillary water absorption (sorptivity) characteristics of self-compacting concrete (SCC). Portland cement (PC) concrete and two types of SCC, SCC-I with fly ash (30% FA/70% PC) and SCC-II with silica fume (10% SF/90% PC), specimens were prepared and cured in three different curing conditions (standard 20°C water, sealed and air cured) for the periods of 3, 7, 14 and 28 days. At the end of each curing period, compressive and tensile strengths and ultrasonic pulse velocity (UPV) values were determined; sorptivity coefficents were determined at 28 days. The results indicated that SCC-II specimens gave higher compressive and tensile strength and lower sorptivity coefficient values than those of corresponding SCC-I and PC concrete specimens, regardless of curing regimes and age of concrete. The results also showed a good correlation between the strength development of concrete and its sorptivity, i.e., as the compressive and tensile strengths increased due to the hydration, the sorptivity coefficients decreased significantly

Clinical and Surgical Evaluation of Perineal Hernia in Dogs: 41 Cases

Besalti, Omer/0000-0002-7819-9094;WOS: 000278958100007The purpose of the study was to report the clinical and surgical records of perineal hernia and associated rectal pathology with epidural morphine analgesia in 41 dogs. Fourty one dogs suffered from perineal hernia were included into the study with the age varied from 4.5 to 16 years. Eleven dogs had bilateral while the other 30 had unilateral (17 right, 13 left) perineal hernia. The clinical signs were perianal swelling (n=41), severe tenesmus (n=19), dyschesia (n=9), proctitis (n=7), fecal incontinence (n=4), stranguria (n=2) and hematuria (n=1). Associated rectal pathologies were diverticulation (n=15), dilatation (n=4), deviation (n=3) and sacculation (n=1). The rectal diverticulum was corrected by extraluminal plication (n=12) or rectal resection (n=3). Internal obturator muscle flap transposition was used to repair the hernia in all cases. Postoperative pain was subjectively evaluated and scores were "no pain" in 10 cases, mild in 28 cases, moderate in 3 cases. Mean follow-up time was 27.3 months (range 4 months to 5 years) and the recurrence was observed only in three cases postoperatively. In conclusion, combined perineal herniorraphy with internal obturator muscle transposition and rectal wall repairment can be carried out at the same time and epidural morphine administration provide adequate analgesia for these operations

Influence of self-compacting concrete on the lateral pressure on formwork

The paper describes a study carried out to examine the effect of self-compacting concrete (SCC) on the lateral pressure on formwork. This comprised two series: (a) control tests, with SCC and comparative concretes (Portland cement (PC) and superplasticised, high-consistence (SP-HC)) cast in 8·0 m columns and walls, and measurements made of concrete and pore water pressures (ten elements) and (b) site tests, with similar properties considered on actual reinforced SCC members during their construction (seven elements). In the control tests, concrete was poured from above to the rising surface at slow (3·0 m/h) and fast (80·0 m/h) rates of rise (with compaction used in the PC and SP-HC concretes only). The results from these indicate that maximum concrete pressures with SCC were slightly lower than those of the comparative concretes at both rates of rise and in columns and walls. Pore water pressures were less than concrete pressures, except with the fast rate of rise for SCC and SP-HC concrete, where the reverse occurred (with the concretes having similar values or SCC slightly higher), which seemed to relate to the concrete properties/pour details and differences in concrete/pore water pressure measurement methods. Maximum pressures for SCC in the control tests were less than hydrostatic and those calculated using the CIRIA report 108 guidance method ( Clear and Harrison, 1985 ). For the site tests, where base-to-top pouring was mainly used (i.e. concrete was passed by way of a hopper at the top of the formwork through a pipe running to its base and kept in place throughout the pour) maximum pressures for SCC were found to exceed hydrostatic in some cases, indicating that this method may give higher pressures. To investigate this further, data from the literature covering SCC pressure measurements on formwork were examined. These showed general agreement with the results of the current study using base-to-top pours and where concrete pumping from below had been adopted, which tended to be at the upper end of the maximum pressure range for SCC. Consideration is given to how SCC may fit within CIRIA 108 for estimating concrete pressure on formwork. </jats:p

Obstacles to Providing Urinary Incontinence Care Among Nurses in Turkey: A Descriptive Study.

Nurses play an important role in identifying, evaluating, monitoring, and managing patients with urinary incontinence (UI)

Obstacles to Providing Urinary Incontinence Care Among Nurses in Turkey: A Descriptive Study

WOS: 000496718300003PubMed: 31702991Nurses play an important role in identifying, evaluating, monitoring, and managing patients with urinary incontinence (UI). PURPOSE: This study was conducted to determine nurses' knowledge, attitudes, practices, and obstacles to managing patients' UI. METHODS: A descriptive study was conducted between September 2017 and February 2018 at 2 university hospitals, 2 private hospitals, and 4 state hospitals in a metropolitan city in Turkey. All registered nurses present at the times of data collection were eligible to participate. After providing informed consent, they were asked to complete a 25-item demographic characteristic questionnaire, a 7-item UI assessment and care implementation form, a 12-item form assessing obstacles faced during UI care provision, a 24-item UI knowledge questionnaire (higher scores indicated more knowledge; a score of 70% correct was considered adequate), and the Urinary Incontinence Attitude Scale. The latter comprised 15 Likert-type questions that measures attitudes toward UI symptoms, treatment, and prevention (maximum score of 60; higher scores infer positive attitude). Data were collected and entered into a software program for statistical analysis including Mann Whitney U, chi-square, and correlation tests. Incomplete forms were excluded. RESULTS: Of the 475 potential participants, 254 nurses completed all forms; 228 (89.8%) were women, 177 (69.7%) had a bachelor's degree, 146 (57.5%) worked in a state hospital, and 105 (41.3%) worked for 2 to 3 years. The mean score for UI knowledge was 15.22 +/- 3.43 (range 0-24), and the mean attitude score was 46.40 +/- 5.50 (range 15-60). The major nurse- or hospital-related obstacles to providing UI care were a lack of systems for patient follow-up (67.7%) and lack of patient education materials (60.2%). A weak positive correlation was noted between UI knowledge level and attitude (r = 0.263; P =.000). CONCLUSION: Although nurses had a positive attitude toward UI, UI knowledge scores were low. Lack of patient follow-up systems and patient education materials were important obstacles to nurses providing UI care. In addition to addressing these obstacles, postgraduation evidence-based UI education for nurses is needed to optimize care