Muhammad Hanif — новинки

Pakistan is facing an intense crisis in conventional energy resources. Utilization of unlimited solar energy will help in minimizing the dependency on conventional energy resources. The purpose of the study was to develop a high performance flat plate solar collector that would be used as a solar drier for various fruits and vegetables. A small scale flat plate solar collector (1.8 x 0.9 m) connected to a drying chamber was developed at the Department of Agricultural Mechanization, Faculty of Crop Production Sciences, Khyber Pakhtunkhwa Agricultural University Peshawar, Pakistan. Efficiency of collector was evaluated at seven air flow rates, one natural (0.57 kg.min-1) and six forced air flow rates (2.84, 5.68, 8.52, 11.37, 14.2 and 17.05kg.min-1) under three ambient temperatures of 20, 22 and 24oC. Results showed that flow rate significantly (P < 0.000) affected the efficiency of flat plate solar collector. Efficiency increased from 19.1 % at the natural flow rate to 56 % at a 17.05 kg.min-1.Efficiency also significantly (P < 0.000) increased from 53 to 55.1 % with an increase in ambient temperature from 22 to 24oC.

A high performance parabolic trough solar collector was developed during this study and was used for drying of vegetables and fruits. The materials used are easily available in the markets and included steel sheet with high power of reflecting light, steel pipe, angle iron and fully insulated drying box. The concentrating collector was a tilted at 34°south (Equivalent to the latitude of Peshawar). The concentrating reflector has a reflecting surface area of 2.9 m2 and focal length of 0.17 m. The length and width of the collector were 2.4 m and 1.21 m, respectively. The absorber having a surface of 0.376 m2 was fixed in front of the reflector at the distance equal to focal length. The heated air was flowing through fan from absorber tube to drying box. The maximum temperature of the absorber was 140 oC. The drying box was a 1 m x 0.57 m x 0.55 m box fully insulated. All Fruits and vegetable were dried with high air flow rate (1.72 kg.min-1). Efficiency was determined by taking the ratio of heat available at the collector in

The problem of sampling with probability proportonal to a size measure and with some control over the probabilities of joint selection of pair''s of units has a history that goes back to about 1943.It is also well known that the problems related to sampling witout replacement with unequal probabilities have attracted and continue to attract the attention of many scholars and statisticians especially in recent years. In this monograph extensive dealing to design based and model based has been coverd. Some new estimators have been suggested to solve many problems. Most important point which has discussed is recommendation for users.

The concept of two-phase sampling was first given by Neyman (1938), later on several simple and general regression and ratio estimators have been suggested, starting from Mohanty (1967), Srivastava (1970), Chand (1975), Kiregyera (1980, 84), Mukerjee et al. (1987), Srivastava et al.(1990), Roy (2003)and Samiuddin and Hanif (2006,07). Use of multi-auxiliary information for ratio and regression estimators, were considered, by Olkin (1958), Goswami and Sukhatme (1965), Raj (1965), Rao and Mudholkar (1967), Tripathi (1970, 1976), Tripathi and Ahmed (1995), Sen (1972), Tripathi (1987), Singh and Namjoshi (1988), Tripathi and Khattree (1989), Tripahi and Chaubey (1993), Ahmed (2003), Martin and Steven (2004) and Ahmad at el. (2008). In this monograph we have provided general classes of regression and ratio estimators for two-phase and multi-phase sampling using multi-auxiliary variables for estimating single as well as multiple variables of interest.The theoretical developments provided in this monograph can be useful in multipurpose surveys in which the problem is to estimate population means of several variables simultaneously in the field like agricultural, forestry etc.

Unequal Probability Sampling has been efficiently used for estimation of population characteristics. Several developments have been made from time to time to increase the precision of estimates. In this book we present some new methods of estimation in unequal probability sampling. Some selection procedures have been discussed for use with the Horvitz and Thompson (1952) estimator. We have also proposed a general selection procedure which yields several selection procedures as special case. We have also discussed the method of developing the approximations for variance formulae for Horvitz and Thompson (1952) estimator. Some new estimators have been discussed alongside their design and model based study. The empirical comparison of proposed techniques has also been given with some well known estimation techniques of unequal probability sampling.

As we all know that sampling with unequal probability plays most important role in large scale sample surveys, therefore in this monograph some recent developments regarding this topic has been discussed. Moreover since joint probability is difficult calculate therefore some approximations of the joint probability have been derived. Special attention has been given to general theory of arbitrary probability. For this theory sampling with replacement and without replacement are the special cases of this general theory. Generalized Murthy estimator has also been discussed in details.

This book intended to cover the overview of unequal probability sampling and Generalization of Murthy''s (1957) estimator. The researcher in the field of survey sampling can get benefit from this book. This book covers an overview of the unequal probability sampling, work done for Horvitz and Thompson (1952), Raj(1956) and Murthy (1957) estimators. Simulation and Empirical studies are conducted to discuss the performance of various available estimators for unequal probability sampling.

Researchers in serious games area and professionals in stroke rehabilitation, working collaboratively in explorative interdisciplinary research studies in order to develop usable and effective applications. This research study aims to investigate the role and usefulness of Video Capture Virtual Reality Technology (VCVRT) in motor impairment rehabilitation, to identify and explore the importance of this technology in healthcare, specifically in motor impairment rehabilitation. The authors concluded from the research study that video capture virtual reality technology is applicable for motor impairment rehabilitation while considering following factors, i.e. Physiotherapist centered approach, a gaming framework where a portfolio of games can be assembled for individual patients, and video capture virtual reality technology is applicable for home based rehabilitation under the supervision of physiotherapist. Furthermore,physiotherapists'' concerns and importance in the intervention of serious games and healthcare area are highlighted by this research work.