since the promenades allocate the part of the country's revenues, therefore, attention to its valuation is very important. springs in desert area are the most prominent of natural landscapes. more study in country investigates recreational value using double– bounded dichotomous choice. but in this study, single-bounded dichotomous choice has been used because of this approach is more like...

in this paper the partial and total factors productivities of isfahan province industries are analyzed. the two digit isic yearly data is used for period 1972-1993 . the results shoe that the average partial labor productivity are 6/8 and 2/2 mil. rials which are corresponded to chemical and wood industries, respectively. the average labor productivity of all industries is roughly constant befo...

Cement concrete and other cement-based composites find wide application in the construction industry. The manufacturing of cement releases a large amount CO2, so use has become major area environmental concern. Attempts have been made to minimize quantity con- crete by replacing it with supplementary cementitious materials. Geopolymer is one those potential candidates for alternative mate- rial...

The Prime Power Conjecture (PPC) states that abelian planar diierence sets of order n exist only for n a prime power. Evans and Mann 2] veriied this for cyclic diierence sets for n 1600. In this paper we verify the PPC for n 2;000;000, using many necessary conditions on the group of multipliers.