The measurement errors problem is endemic in many econometric studies, and one of the oldest known statistical problems. Instrumental variable (IV) method is one of the popular solutions adopted to deal with the mismeasured variables in statistical and econometric analyses. This paper proposes an efficient IV estimator to the parameters of the simple regression model where both variables are subject to measurement errors. The proposed IV is defined using simple mathematical transformation of the manifest independent variable (mismeasured variable). The proposed method is straightforward, and easy to implement. The theoretical superiority of the proposed estimator over the existing IV based estimators due to Wald (1940), Bartlett (1949), and Durbin (1954) is established by analytical comparison and geometric expositions. Simulation based numerical comparisons of the proposed estimator with four different existing estimators are also included.

Abstract- Many methods have been applied in order to reduce nitrate concentration in aqueous solutions, among them

is the adsorption onto the surface of agricultural wastes. In this study, batch experiments were carried out to investigate

the adsorption of nitrate onto olive pomace (OP), a solid by-product of olive oil industry. To achieve this, six parameters

were studied by varying only one parameter at a time. These parameters were the effect of: pH, contact time,

temperature, adsorbent weight, agitation speed and nitrate concentration. The optimum pH was found to be 5, while the

optimum time was 75 minutes. Nitrate removal percentage was found to increase with increasing adsorbent weight or

temperature, with 92.5% of nitrate removed by using 2 g of OP and 48% of nitrate was removed at 60ºC. Generally,

agitation speed increased the nitrate removal percentage, while high initial concentration of nitrate was found to decrease

its removal percentage. These findings, combined with the low cost of OP and its abundance, suggest that OP is a

potential adsorbent for nitrate removal provided that the optimum conditions are applied. Applying this method for

nitrate removal will make drinking water safer to drink and wastewater safer to discharge.

The object of the present paper is to derive some results on differential subordination associated with a generalized derivative operator for certain normalized analytic functions in the open unit disc. The authors establish sandwich type theorems. These results extend many previously known results.

Energy flow bottlenecks in high voltage transmission lines known as congestions are one of the challenges facing power utilities in fast developing countries. Bottlenecks occur in selected power lines when transmission systems are operated at or beyond their transfer limits. In these cases, congestions result in preventing new power supply contracts, infeasibility in existing contracts, price spike and market power abuse. The “Superconductor Technology” in electric power transmission cables has been used as a solution to solve the problem of bottlenecks in energy transmission at high voltage underground cables and overhead lines. The increase in demand on power generation and transmission happening due to fast development and linked to the intensive usage of transmission network in certain points, which in turn, lead to often frequent congestion in getting the required power across to where it is needed