let r be an associative ring with unity. an element a in r is said to be r-clean if a = e+r, where e is an idempotent and r is a regular (von neumann) element in r. if every element of r is r-clean, then r is called an r-clean ring. in this paper, we prove that the concepts of clean ring and r-clean ring are equivalent for abelian rings. further we prove that if 0 and 1 are the only idempotents...

In the present study, the high viscosity of the jatropha curcas oil was decreased by preheating. The effect of fuel inlet temperature on performance of diesel engine is evaluated. A single cylinder, four stroke, constant speed, air cooled, direct injection diesel engine developing a power output of 3.7 kW at 1500 rev/min typically used in agricultural sector was tested using neat jatropha oil a...

in this work, we investigate the transfer of some homological properties from a ring $r$ to its amalgamated duplication along some ideal $i$ of $r$ $rbowtie i$, and then generate new and original families of rings with these properties.

for a ring endomorphism $alpha$ and an $alpha$-derivation $delta$, we introduce a concept, so called skew $pi$-armendariz ring, that is a generalization of both $pi$-armendariz rings, and $(alpha,delta)$-compatible skew armendariz rings. we first observe the basic properties of skew $pi$-armendariz rings, and extend the class of skew $pi$-armendariz rings through various ring extensions. we nex...

A 9 pm cutoff 256x256 hand-held quantum well infrared photodetector (QWIP) camera has been demonstrated. Excellent imagery, with a noise equivalent differential temperature (NEAT) of 26 mK has been achieved. In this paper, we discuss the performance of this portable long-wavelength infrared camera in quantum efficiency, NEAT, minimum resolvable temperature difference (MRTD), uniformity, etc. an...

Let R be a discrete valuation ring with a unique maximal ideal πR and a quotient field K, and let F = R/πR be the residue class field. Let n ≥ 2 be an integer and {λij | 1 ≤ i, j ≤ n} a set of n integers satisfying λii = 0, λik + λkj ≥ λij , λij + λji > 0 (if i = j) for all 1 ≤ i, j, k ≤ n. Then Λ = (πijR) is a basic semiperfect Noetherian R-subalgebra of the full n× n matrix algebra Mn(K). We ...

in this paper, we introduce the new notion of n-f-clean rings as a generalization of f-clean rings. next, we investigate some properties of such rings. we prove that mn(r) is n-f-clean for any n-f-clean ring r. we also, get a condition under which the denitions of n-cleanness and n-f-cleanness are equivalent.

a topoframe, denoted by $l_{ tau}$,  is a pair $(l, tau)$ consisting of a frame $l$ and a subframe $ tau $ all of whose elements are complementary elements in$l$. in this paper, we define and study the notions of a$tau $-real-continuous function on a frame $l$ and the set of realcontinuous functions $mathcal{r}l_tau $ as an $f$-ring.we show that $mathcal{r}l_{ tau}$is actually a generalization ...