Subsidizing carbon sequestration via forestry in Maryland: A cost-benefit assessment

Carbon sequestration by forestry is one way to mitigate climate change, and policy incentives are in place to encourage private investment in forestry. State and federal forestry cost-share programs subsidize the establishment of trees and the improvement of existing forested land. The objective of this research was to determine the effectiveness of such programs in Maryland and to compare the monetized benefits from permanently sequestered carbon with the current subsidies. To meet this objective, private and social cost-benefit analyses were conducted for three forestry investment scenarios in Maryland that coincide with the main cost-share programs available there. Sensitivity analysis considered a range of values for the social cost of carbon, the discount rate, and program implementation costs. ^ The first program considered was the state funded Woodland Incentive Program (WIP), which provides cost-share assistance for improving timber management. According to the cost-benefit analysis results, the program provides sufficient incentives to induce participation. For a discount rate of 5%, the investment in pre-commercial thinning with participation in WIP increases discounted returns by $60.62 per acre. However, the total program enrollment over the past eight years was only 24,443 acres, compared to GIS analysis results that show approximately 737,000 acres across Maryland are eligible for the program. The total cost share assistance provided by WIP for a timber management improvement practice of pre-commercial thinning was$81.34 per acre, while from society’s view, the discounted carbon sequestration benefits provided by the improved timber stand were $146.82 per acre. By basing the cost-share assistance on the carbon benefits, and so increasing the subsidies, potential and actual program participation may converge. ^ Two land conversion programs were considered: the federally funded Environmental Quality Incentives Program (EQIP) and the state funded Lawn to Woodland (L2W) Initiative. The cost-benefit analysis results show that the conversion from cropland to forest through EQIP does not provide enough incentive to induce program participation. Cropland rents generate income far greater than the benefits from forestry conversion, even when carbon benefits are included. In this case, the program is already providing subsidies larger than the carbon sequestration benefits, and the actual participation of only 344 acres between 2009 and 2013 is still very low. However, when using the pastureland rent, which is about half of the cropland rent, the conversion to forest is much more likely. There are around 750,000 acres of pastureland in Maryland that could be converted to forest to increase carbon sequestration across the state. ^ The conversion from lawn to forest through L2W provided contrasting results. Since timber harvest is unlikely following the conversion from lawn to forest, the carbon benefits are much higher. The cost-share assistance was$335.91 per acre, and the discounted carbon benefits from the conversion were $1,245.87 per acre. Cost-share assistance based on the benefits from permanently sequestered carbon could justify increasing the incentive to participate by almost four times. Since neither land use in this scenario provides financial returns to the owner, the investment decision depends largely on the aesthetic values of lawn versus forest that the landowner possesses, which are difficult to estimate. GIS analysis estimated that approximately 230,000 acres are eligible for this new program across Maryland. ^ Maryland is at the forefront when compared to other states, supplementing federal cost-share programs with its own resources to combat climate change. This analysis suggests the state financed initiatives may exhibit the potential to enhance carbon sequestration more than the federal programs, and for each state program there was scope to increase subsidies given the value of carbon benefits realized

Air pollution control with semi-infinite programming

Environment issues are more than ever important in a modern society. Complying with stricter legal thresholds on pollution emissions raises an important economic issue. This paper presents some ideas in the use of optimization tools to help in the planning and control of stationary pollution sources. Three main semi-infinite programming approaches are described. The first consists in optimizing an objective function while the pollution level in a given region is kept bellow a given threshold. In the second approach the maximum pollution level in a given region is computed and in the third an air pollution abatement problem is considered. These formulations allow to obtain the best control parameters and the maxima pollution positions, where the sampling stations should be placed. A specific modeling language was used to code four academic problems. Numerical results computed with a semi-infinite programming solver are shown

Breakdown of the few-level approximation in collective systems

The validity of the few-level approximation in dipole-dipole interacting collective systems is discussed. As example system, we study the archetype case of two dipole-dipole interacting atoms, each modelled by two complete sets of angular momentum multiplets. We establish the breakdown of the few-level approximation by first proving the intuitive result that the dipole-dipole induced energy shifts between collective two-atom states depend on the length of the vector connecting the atoms, but not on its orientation, if complete and degenerate multiplets are considered. A careful analysis of our findings reveals that the simplification of the atomic level scheme by artificially omitting Zeeman sublevels in a few-level approximation generally leads to incorrect predictions. We find that this breakdown can be traced back to the dipole-dipole coupling of transitions with orthogonal dipole moments. Our interpretation enables us to identify special geometries in which partial few-level approximations to two- or three-level systems are valid

Coherent control in a decoherence-free subspace of a collective multi-level system

Decoherence-free subspaces (DFS) in systems of dipole-dipole interacting multi-level atoms are investigated theoretically. It is shown that the collective state space of two dipole-dipole interacting four-level atoms contains a four-dimensional DFS. We describe a method that allows to populate the antisymmetric states of the DFS by means of a laser field, without the need of a field gradient between the two atoms. We identify these antisymmetric states as long-lived entangled states. Further, we show that any single-qubit operation between two states of the DFS can be induced by means of a microwave field. Typical operation times of these qubit rotations can be significantly shorter than for a nuclear spin system.Comment: 15 pages, 11 figure

Lifetimes of Confined Acoustic Phonons in Ultra-Thin Silicon Membranes

We study the relaxation of coherent acoustic phonon modes with frequencies up to 500 GHz in ultra-thin free-standing silicon membranes. Using an ultrafast pump-probe technique of asynchronous optical sampling, we observe that the decay time of the first-order dilatational mode decreases significantly from \sim 4.7 ns to 5 ps with decreasing membrane thickness from \sim 194 to 8 nm. The experimental results are compared with theories considering both intrinsic phonon-phonon interactions and extrinsic surface roughness scattering including a wavelength-dependent specularity. Our results provide insight to understand some of the limits of nanomechanical resonators and thermal transport in nanostructures

Measuring the quantum efficiency of single radiating dipoles using a scanning mirror

Using scanning probe techniques, we show the controlled manipulation of the radiation from single dipoles. In one experiment we study the modification of the fluorescence lifetime of a single molecular dipole in front of a movable silver mirror. A second experiment demonstrates the changing plasmon spectrum of a gold nanoparticle in front of a dielectric mirror. Comparison of our data with theoretical models allows determination of the quantum efficiency of each radiating dipole.Comment: 4 pages, 4 figure

Comparative shotgun proteomic analysis of Clostridium acetobutylicum from butanol fermentation using glucose and xylose

<p>Abstract</p> <p>Background</p> <p>Butanol is a second generation biofuel produced by <it>Clostridium acetobutylicum </it>through acetone-butanol-ethanol (ABE) fermentation process. Shotgun proteomics provides a direct approach to study the whole proteome of an organism in depth. This paper focuses on shotgun proteomic profiling of <it>C. acetobutylicum </it>from ABE fermentation using glucose and xylose to understand the functional mechanisms of <it>C. acetobutylicum </it>proteins involved in butanol production.</p> <p>Results</p> <p>We identified 894 different proteins in <it>C. acetobutylicum </it>from ABE fermentation process by two dimensional - liquid chromatography - tandem mass spectrometry (2D-LC-MS/MS) method. This includes 717 proteins from glucose and 826 proteins from the xylose substrate. A total of 649 proteins were found to be common and 22 significantly differentially expressed proteins were identified between glucose and xylose substrates.</p> <p>Conclusion</p> <p>Our results demonstrate that flagellar proteins are highly up-regulated with glucose compared to xylose substrate during ABE fermentation. Chemotactic activity was also found to be lost with the xylose substrate due to the absence of CheW and CheV proteins. This is the first report on the shotgun proteomic analysis of <it>C. acetobutylicum </it>ATCC 824 in ABE fermentation between glucose and xylose substrate from a single time data point and the number of proteins identified here is more than any other study performed on this organism up to this report.</p

An ultra-sensitive pulsed balanced homodyne detector: Application to time-domain quantum measurements

A pulsed balanced homodyne detector has been developed for precise measurements of electric field quadratures of pulsed optical quantum states. A high level of common mode suppression (> 85 dB) and low electronic noise (730 electrons per pulse) provide a signal to noise ratio of 14 dB for the measurement of the quantum noise of individual pulses. Measurements at repetition rates up to 1 MHz are possible. As a test, quantum tomography of the coherent state is performed and the Wigner function and the density matrix are reconstructed with a 99.5% fidelity. The detection system can also be used for ultrasensitive balanced detection in cw mode, e.g. for weak absorption measurements.Comment: 3 pages, submitted to Optics Letter

Consequences of hydroxyl generation by the silica/water reaction

Water diffusing into silica surfaces gives rise for several effectson diffusion behaviour and mechanical properties. Water added to silica glass increases its specific volume so that the silica expands near the surface. Mechanical boundary conditions give rise for compressive “swelling stresses”. This fact provides a tool for the interpretation of many experimental observations from literature

Consequences of hydroxyl generation by the silica/water reaction - Part II: Global and local Swelling - Part III: Damage and Young\u27s Modulus

Water diffusing into silica surfaces gives rise for several effects on diffusion behaviour and mechanical properties. In a preceding booklet, we focused on diffusion and fiber strengths and deformations which were obtained by water soaking under external loading. In the present booklet we deal with results and interpretations of strength increase in the absence of applied stresses