Mathematical modelling and simulation of the dehumidifier for the tropical region of Malaysia
In this paper, mathematical model for an adiabatic dehumidifier of liquid desiccant air conditioning system is presented. Regression approach is used to generate the mathematical relation between enthalpy and humidity ratio. Flow-pattern between air & desiccant mainly affects the performance of adiabatic dehumidifier therefore to get proper dehumidification counter-flow configuration is considered as previous studies show that counter-flow direction of air to desiccant has better dehumidification results. For validation, results of present study were compared with those of numerical and analytical results of previous studies, and the agreement was found to be quite satisfactory. The developed mathematical model is then used to study the performance analyses of adiabatic-dehumidifier for the tropical region of Malaysia. Analyses are made for the week having very high range of humidity ratio (18 - 19.5 g/kg). The main concern of the current article is given on moisture removal from the ambient air according to thermal comfort-zone.
A novel method to evaluate the performance of liquid desiccant air dehumidifier system
The system efficiency of desiccant air dehumidification is usually evaluated by a coefficient of performance (COP) that is defined as the ratio of the cooling capacity and the sum of net electrical power input. The common efficiency evaluation method has many weaknesses especially if applied on liquid type of desiccant, low humidity different between inlet and outlet, and also on the system that has automatic operating control. This paper offers a solution for weaknesses of common method with a proposed novel method to evaluate the performance of liquid desiccant air dehumidification system.
Work, Status, and Income: Men in the American Occupational Structure since the Late Nineteenth Century
The historical record rarely presents researchers with precisely the evidence they desire. This is particularly true for social historians and like-minded scholars, whose subjects left precious few signs of their passing. Consequently, certain data have borne a disproportionate evidentiary load in social-historical research. The occupation a person pursued is one key piece of information on which scholars have come to depend. Our understanding of the historical social structure and where people fit into it is bound up with the interpretation of occupations. But this reliance on occupation as the primary social locator in historical research depends on some largely unexamined premises. Whether scholars group occupations or convert them into numerical status measures, they make assumptions about the nature of the occupational structure. When researchers incorporate change over time into their analyses, they suggest that the meaning of occupations remained stable for the purpose of measuring social mobility, class position, or group status-attainment. This assumption has been the subject of little discussion and even less research. For all the use to which historians have put occupation, there has been little effort to assess systematically its stability as a social or economic indicator.