for a simple digraph $g$ of order $n$ with vertex set${v_1,v_2,ldots, v_n}$, let $d_i^+$ and $d_i^-$ denote theout-degree and in-degree of a vertex $v_i$ in $g$, respectively. let$d^+(g)=diag(d_1^+,d_2^+,ldots,d_n^+)$ and$d^-(g)=diag(d_1^-,d_2^-,ldots,d_n^-)$. in this paper we introduce$widetilde{sl}(g)=widetilde{d}(g)-s(g)$ to be a new kind of skewlaplacian matrix of $g$, where $widetilde{d}(g...

abstract intensive and inefficient use of energy leads to degradation of natural resources and environmental problems. this study evaluated the relationship between the energy of consumed inputs and yield of tomato, cucumber and melon using the cobb–douglas production function. the data were collected from 90 farmers in firoozabad using a questionnaire. the farmers were chosen by simple random ...

abstract the aim of this study was to determine the input–output energy consumption in different levels of tomato production. the data used in the study were obtained from 140 tomato growers in different villages of marand township by using a face to face questionnaire. the results showed that the amount of energy consumed in tomato production was 65.2 gjha-1 which about 51% of this was generat...

the study examined gender analysis of energy use for rice production in north central nigeria using a sample of 60 rice farmers. an analysis of gender relations provides the information on the different conditions men and women face, and the different effects that policies and programs may have on them. simple descriptive statistics were used to analyze the data. energy efficiency and energy pr...

in this paper smart operation of micro energy hub is presented. energy hub system consists of certain energy hubs and interconnectors that are coordinated by energy hub system operator. an energy hub contains several converters and storages to serve demanded services in most efficient manner from available energy carriers. in this paper, the flexibility of energy delivery point is enhanced u...

for a simple connected graph $g$ with $n$-vertices having laplacian eigenvalues‎ ‎$mu_1$‎, ‎$mu_2$‎, ‎$dots$‎, ‎$mu_{n-1}$‎, ‎$mu_n=0$‎, ‎and signless laplacian eigenvalues $q_1‎, ‎q_2,dots‎, ‎q_n$‎, ‎the laplacian-energy-like invariant($lel$) and the incidence energy ($ie$) of a graph $g$ are respectively defined as $lel(g)=sum_{i=1}^{n-1}sqrt{mu_i}$ and $ie(g)=sum_{i=1}^{n}sqrt{q_i}$‎. ‎in th...