Investigating the household standard of living is an important subject with respect to targeting problem in poverty alleviation programs. By doing so, at first, we can identify the poor, indirectly and then, we can targetize the assistants to them. Most of the studies on standard of living, based on survey data, are confronted with the sample selection error (bias). Sample selection bias is not the only feature of standard of living studies, but also, it occurs when the observations have self-selectivity property, which in turn might result in bias and inconsistency with estimators. The main purpose of the paper is the introduction of a general methodology of correcting selectivity bias, with application to the regression of standard of living in rural areas of Iran.

In this work, we have modified a synthesized Y-type zeolite (Si/Al = 2. 5), with three different amines to investigate the influence of adsorbent’ s surface modification on CO2 selectivity over CH4. The pristine and amine-functionalized NaY zeolites were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) analysis, and N2 adsorption. The results showed that the structure of zeolite was preserved after amine modification. The adsorption capacity of CO2 and CH4 on these adsorbents was measured by the volumetric method at 298 K and 348 K. In comparison to CH4, CO2 was preferentially adsorbed on these adsorbents. the results demonstrated that incorporation of amines into zeolites structure improved significantly the selectivity towards carbon dioxide so that the optimal selectivity of CO2 over CH4 reached to 4. 04 on zeolite modified with 2-methylaminoethanol at 348 K. Chemical interaction between adsorbate and sorbents as well as the steric effects were assessed to be the main reasons of high selective adsorption of carbon dioxide on amine-functionalized zeolites. Two of the most common adsorption models, the Langmuir and Sips isotherms, were used to correlate the experimental data of CO2 adsorption on the adsorbents The results revealed that the amine-functionalized NaY zeolites could be a good sorbent for use in flue and natural gas separation processes.

Sediment selectivity during transport may provide basic information for evaluating on-site and off-site impacts of the soil erosion. Limited information is, however, available on the selectivity of sediments in rill erosion, particularly in the rainfed furrows. Toward this, the sediment selectivity was investigated in three soil textures (loam, loamy sand sand clay loam) under 10% slope using 90 mm. h-1 rainfall intensity for 40 min. Soil samples were passed from a 10 mm sieve and packed in to the erosion flume with 0. 4m × 4 m in dimensions. Particles size distribution (PSD) was determined in the sediments (PSDs) and compared with the original soil PSD (PSDo). The proportion of PSDs and PSDo was stated as PSDs/PSDo to show the selectivity of soil particles by rill erosion. Based on the results, all three soils appeared as the coarse particles (coarse sand and very coarse sand) in sediments with the PSDs/PSDo>1, indicating the higher selectivity of these particles by rill erosion. Loamy sand was the most susceptible soil to rill erosion among the studied soils, which generated a higher runoff (0. 0035 m2. s-1) and sediment load (0. 1 kg. m-1. s-1) during rainfall. The PSDs of this soil were similar to those of the original soil PSD. This study revealed that the stability of aggregates could be regarded as the major soil factor controlling rill erosion rate and the sediment selectivity in the semi-arid soils. With an increase in the water-stable aggregates, soil infiltration rate and as a consequence, shear stress of flow could be decreased in the rills.