Numerical study of a regenerative counter flow evaporative cooler using alumina nanoparticles in wet channel

The use of Maisotsenko Cycle (M-Cycle) has enhanced the domain of evaporative cooling technologies to sub-wet bulb temperature cooling while ensuring moisture control. Several studies have demonstrated the use of cross-flow heat & mass exchanger (HMX) offers higher cooling capacity; however, it has lower cooling effectiveness and Energy Efficiency Ratio (EER). In contrast, a counter-flow (HMX) offers high cooling effectiveness with lower cooling capacity. In this paper, the performance of counter-flow HMX is enhanced by addition of alumina nanoparticles in feed water due to enhanced heat and mass transfer characteristics of nanofluids compared to original base fluid. Here, a mathematical model is formulated by incorporating the nanofluids in a selected control volume. The developed model is solved numerically on a discretized HMX length. Initially, the model is benchmarked against previously published results using water as base fluid. A comparison between HMX performance using water and alumina nanofluid is performed in terms of Performance Enhancement Ratio (PER). PER indicates 1-18% increase in cooling effectiveness, 18-43% increase in cooling capacity and 9-19% increase in EER by using alumina in water when working air temperature is increased from 20°C to 45°C. Similarly, an increase in PER is also observed by changing air velocity. Increase of 41% is observed in cooling capacity and 18% increase in EER is observed by changing particle volume fraction from 0 to 2 percent. This research identifies ways to reduce the carbon emissions of a building by increasing the energy efficiency of existing evaporative cooling technology using nanofluids

Relation of corporate governance with financial performance

The intention of the work is to prove that corporate governance is essential to uninterrupted operation of any corporation, while more consideration to the process such that governance. Hence it is transparent what is commonly intermediate by corporate governance. This work proves a link with the corporate governance and firm financial performance in insurance industry of Pakistan. It included three variables which are Audit committee independence, board independence and CEO duality for corporate governance. The degree of firm's performance is limited by return on equity and asset. This work gives a positive direction for exploring this concept

A comparison of drift wave stability in stellarator and tokamak geometry

The influence of plasma geometry on the linear stability of electrostatic ion-temperature-gradient driven drift modes (ITG modes) is investigated. An advanced fluid model is used for the ions together with Boltzmann distributed electrons. The derived eigenvalue equation is solved numerically. A comparison is made between an H – 1NF [Fusion Technol. 17, 123 (1990)] like stellarator equilibrium, a numerical tokamak equilibrium and the analytical s - alpha equilibrium. The numerical and the analytical tokamak are found to be in good agreement in the low inverse aspect ratio limit. The growth rates of the tokamak and stellarator are comparable whereas the modulus of the real frequency is substantially larger in the stellarator. The threshold in Ln/LT for the stellarator is found to be somewhat larger. In addition, a stronger stabilization of the ITG mode growth is found for large L n / R in the stellarator case

Determinants of Commercial Banks Profitability: Panel Data Evidence from Pakistan

Purpose- The rationale of this study is to investigate the determinants of commercial banks profitability in Pakistan over the period 2004-2010 Design/methodology/approach- Multiple regression analysis using cross sectional time series data is used to test the relationship between return on asset after tax as a dependent variable and various independent variables Findings- The results indicate that internal factors such as liquidity, firm’s efficiency, assets composition and deposit composition as well as external factors such as firm size have significant impact on the profitability of commercial banks. Research limitations/implications- The sample size being taken in this study is small due to the unavailability of data because the most commercial banks annual reports are computerized since 2006. More evidence is needed on the determinants of commercial bank profitability in Pakistan to generalize the results beyond these five banks or to different study periods. Practical implications- The study might help the commercial banks managers to concentrate on the factors actually determine the banks performance so that they will be able to take more strategic approach to add value to their organizations. Originality/value- The study adds to the literature on the commercial banks profitability determinants and particularly such study has not been conducted in Pakistan so far. Keywords: Commercial banks profitability, Banks, Pakista

Thermal performance enhancement of a cross-flow-type maisotsenko heat and mass exchanger using various nanofluids

© 2018 by the authors. The incorporation of a Maisotsenko (M) Cycle into an indirect evaporative cooler has led to the achievement of sub-wet bulb temperature without any humidification, thus making it a possible green and sustainable alternative for handling the cooling load of a building. In this work, the thermal performance of a cross-flow heat and mass exchanger (HMX) is enhanced by the addition of nanoparticles in the wet channel because they significantly influence the heat and mass transfer characteristics of the base fluid. A governing model for the temperature and humidity variations of the HMX is numerically simulated. Initial benchmarking is achieved using water properties. Afterward, a comparative study is conducted using aluminum-oxide-, copper-oxide-, and titanium-oxide-based nanofluids. Enhancements of 24.2% in heat flux, 19.24% in wet bulb effectiveness, 7.04% in dew point effectiveness, 29.66% in cooling capacity, and 28.43% in energy efficiency ratio are observed by using alumina-based nanofluid as compared to water in the wet channel of the cross-flow HMX. Furthermore, a particle volume concentration of 1% and a particle diameter of 20nm are recommended for maximum performance

Frequency of metabolic syndrome in psychiatric patients, is this the time to develop a standardized protocol to reduce the morbidity from an acute care psychiatry unit.

OBJECTIVE: To determine the frequency of Metabolic Syndrome among psychiatric patients and to look for the correlation between the two medical conditions. METHODS: The cross-sectional study was conducted from February to April 2013 at the acute care psychiatry in-patient unit at Kingston General Hospital, Ontario, Canada, and comprised adult patients of both genders diagnosed under the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition. For Metabolic Syndrome, definitions outlined by the International Diabetes Federation were used. The patients were divided into two groups on the basis of presence or absence of the Syndrome and were compared for clinical and demographic characteristics. SPSS 22 was used for statistical analysis. RESULTS: Of the 50 patients in the study, 24(48%) were found to have Metabolic Syndrome. Besides, 40 (80%) patients were taking atypical antipsychotics regardless of the diagnosis; 20(83%) among those with the Syndrome, and 20(77%) among those without it. CONCLUSIONS: Patients at high risk of developing metabolic syndrome need to be identified early so that an individualised care plan can be formulated. Identifying the variables to make a management plan is vital

Torsion of ovarian dysgerminoma in a child: role of computed tomography.

Dysgerminomas are malignant germ cell tumors of the ovary that most commonly occur in the adolescent population. Ovarian dysgerminomapresenting with complications like torsion is a rare entity in the pediatric age group. Cross-sectional imaging plays a crucial role in diagnosis, tumor staging before surgical resection, and for planning adjuvant chemotherapy. We report a case of a nine-year-old female who presented to the emergency room (ER) with abdominal distention and abdominal pain. Computed tomography scan revealed a large right-sided pelvic mass with areas of low attenuation, speckled calcification, peritumoral free fluid, and a twisted vascular pedicle that was likely originating from the left adnexa. The right ovary was normal in appearance. Suspicion of a left-sided ovarian tumor with torsion was raised, which was later confirmed on surgery and histopathology of the resected specimen

Dynamic Modelling and Analysis of a Hybrid Power System of Floating Solar PV System for an Offshore Aquaculture Site in Newfoundland

In this article a hybrid power system, a combination of solar and diesel generator (DG) is modeled in MATLAB and the dynamic performance of the system are analyzed considering the design parameters. The said system is designed for an offshore aquaculture site located in Newfoundland, Canada. The paper presents a novel concept of evaluating the dynamic performance of floating solar PV panels over the water surface of the fish farm. The sizing and economic feasibility of the system were carried out on HomerPro. Design is modeled in MATLAB to analyze the impact of dynamic changes on system performance. The system is exposed to variable irradiance, temperature, and load side variations and simulated under each condition. The results presented here confirm the satisfactory and reliable response of the system in all scenarios. The designed system shall replace the existing power source (diesel gen) with green and economical energy resources and will be a great help to bring sustainability in the Canadian aquaculture industry