The Application of Depletion to Geothermal Resources

The energy crisis and the increasing costs of conventional sources of energy have created increased interest in geothermal resources as an alternative energy source. One impediment to the development of geothermal resources is the uncertainty of their status under federal tax law. This note analyzes the application of the depletion provisions of the Internal Revenue Code of 1954 to geothermal resources. Consideration is given to whether geothermal resources are exhaustible, whether they can or should be viewed as heat, and whether heat is a natural deposit or a mineral. Since geothermal resources exist in several forms, and since the depletion provisions may not apply uniformly to all of the forms, the provisions are analyzed to discover which ones might apply to each form of geothermal resources. A background summary of the nature of geothermal resources is provided in part I. Federal tax law is then reviewed in part II to determine which depletion provisions may apply to geothermal resources. Finally, in part III the distinctions among the forms of geothermal resources and the economics of developing these forms are considered in formulating the tax treatment that should be applied to each form

Investigation of phase-separated electronic states in 1.5µm GaInNAs/GaAs heterostructures by optical spectroscopy

We report on the comparative electronic state characteristics of particular GaInNAs/GaAs quantum well structures that emit near 1.3 and 1.5 µm wavelength at room temperature. While the electronic structure of the 1.3 µm sample is consistent with a standard quantum well, the 1.5 µm sample demonstrate quite different characteristics. By using photoluminescence sPLd excitation spectroscopy at various detection wavelengths, we demonstrate that the macroscopic electronic states in the 1.5 µm structures originate from phase-separated quantum dots instead of quantum wells. PL measurements with spectrally selective excitation provide further evidence for the existence of composition-separated phases. The evidence is consistent with phase segregation during the growth leading to two phases, one with high In and N content which accounts for the efficient low energy 1.5 µm emission, and the other one having lower In and N content which contributes metastable states and only emits under excitation in a particular wavelength range

Crafting Moral Infrastructures: How Nonprofits Use Facebook to Survive

We present findings from interviews with 23 individuals affiliated with non-profit organizations (NPOs) to understand how they deploy information and communication technologies (ICTs) in civic engagement efforts. Existing research about NPO ICT use is largely critical, but we did not find evidence that NPOs fail to use tools effectively. Rather, we detail how various ICT use on the part of NPOs intersects with unique affordance perceptions and adoption causes. Overall, we find that existing theories about technology choice (e.g., task-technology fit, uses and gratifications) do not explain the assemblages NPOs describe. We argue that NPOs fashion infrastructures in accordance with their moral economy frameworks rather than selecting tools based on utility. Together, the rhetorics of infrastructure and moral economies capture the motivations and constraints our participants expressed and challenge how prevailing theories of ICT usage describe the non-profit landscape

Effects of low sampling rate in the digital data-transition tracking loop

This article describes the performance of the all-digital data-transition tracking loop (DTTL) with coherent and noncoherent sampling using nonlinear theory. The effects of few samples per symbol and of noncommensurate sampling and symbol rates are addressed and analyzed. Their impact on the probability density and variance of the phase error are quantified through computer simulations. It is shown that the performance of the all-digital DTTL approaches its analog counterpart when the sampling and symbol rates are noncommensurate (i.e., the number of samples per symbol is an irrational number). The loop signal-to-noise ratio (SNR) (inverse of phase error variance) degrades when the number of samples per symbol is an odd integer but degrades even further for even integers

Computer simulation results for PCM/PM/NRZ receivers in nonideal channels

This article studies, by computer simulations, the performance of deep-space telemetry signals that employ the pulse code modulation/phase modulation (PCM/PM) technique, using nonreturn-to-zero data, under the separate and combined effects of unbalanced data, data asymmetry, and a band-limited channel. The study is based on measuring the symbol error rate performance and comparing the results to the theoretical results presented in previous articles. Only the effects of imperfect carrier tracking due to an imperfect data stream are considered. The presence of an imperfect data stream (unbalanced and/or asymmetric) produces undesirable spectral components at the carrier frequency, creating an imperfect carrier reference that will degrade the performance of the telemetry system. Further disturbance to the carrier reference is caused by the intersymbol interference created by the band-limited channel