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Skin grafting continues to be a fundamental component of burn treatment and inherently, a donor site must be created and treated. Burn surgeons agree that specific dressings may have a significant affect on donor site healing, but we have no consensus as to which dressing provides maximum benefit.Retrospective analysis of prospectively collected data from an observational, within-patient controlled assessment of a practice pattern intervention. The project compared donor sites treated with high-density polyethylene plus an overlying layer of bismuth/petroleum gauze to donor sites treated with bismuth/petroleum gauze alone. The primary endpoint was patient reported pain using a standard visual analog scale from 0 (no pain) to 10 (worst possible pain). A 2-point reduction in pain was considered clinically significant. Healing was defined as complete detachment of the dressings and 95% wound re-epitheliazation.A total of 30 patients were observed and analyzed. Both dressings were associated with a mean pain rating of 6 out of 10 (STD= ± 2) and a median pain rating of 6 out of 10 (range = 0-10). Additionally, both dressings were associated with a mean healing time of 20 days (SEM=1.1). The subjective dressing preference showed that a majority of patients had no preference between the two modalities (n = 20). However, when an actual preference was stated (n = 10), bismuth/petroleum gauze alone was preferred by 9 out of 10 patients.Clinically and subjectively, we found no discernible differences between the 2 dressing regimens. Thus, bismuth/petroleum gauze alone is the more cost effective dressing choice. Our burn center continues to use bismuth/petroleum gauze alone as its standard of care for donor site dressings and will continue to try to define the optimal donor site dressing.

Phosphorus (P) fertilization practices and winter cover crops are promoted to protect water quality yet can potentially influence crop yield and profitability. This study examined the impacts of three P fertilizer management practices (no P, fall broadcast P, and spring injected P) and winter annual cover crop use on yields, net returns, and water quality in a no-till corn-soybean rotation. Treatments were replicated in a 4-year field study where sediment, total P, and dissolved reactive P (DRP) losses in edge-of-field surface runoff were continuously monitored. Production budgets were developed for each treatment and coupled with water quality data to identify optimal practices and opportunity costs for improving water quality. Applying P fertilizers increased crop yield regardless of application method or cover crop, but the response was more pronounced in corn than soybean. The cover crop reduced corn grain yield in one year with high temperature and low precipitation but did not impact grain yield in the other corn year or either year of soybean. The most profitable treatment was fall broadcast P fertilizer with no cover crop, which also had the greatest total P and DRP losses and near greatest sediment loss. The lowest-cost methods of reducing total P, DRP, and sediment losses were respectively no P fertilizer without a cover crop ($47.56 kg

We analyze the coupling into a slotted cylindrical cavity operating at fundamental cavity modal frequencies overlapping with the slot’s first resonance frequency through an unmatched formulation th...

In this article, we examine the coupling into an electrically short azimuthal slot on a cylindrical cavity operating at fundamental cavity modal frequencies. We first develop a matched bound formulation through which we can gather information for maximum achievable levels of interior cavity fields. Actual field levels are below this matched bound; therefore, we also develop an unmatched formulation for frequencies below the slot resonance to achieve a better insight on the physics of this coupling. Good agreement is observed between the unmatched formulation, full-wave simulations, and experimental data, providing a validation of our analytical models. We then extend the unmatched formulation to treat an array of slots, found again in good agreement with full-wave simulations. These analytical models can be used to investigate ways to mitigate electromagnetic interference and electromagnetic compatibility effects within cavities.

The adoption of conservation practices is a dynamic process. Factors that vary over time can affect farmers’ decision to adopt and adoption timing. We used a duration model to evaluate the farmer's adoption time for continuous no‐till (CNT), cover crops (CCs), and the variable‐rate application of inputs (VRA). We found that producers who had previously adopted soil conservation practices were more likely to adopt additional complementary practices. Farmers using crop rotation adopted CNT and CCs approximately 48% and 62% faster than farmers without a crop rotation, respectively. The CC adoption time was also reduced by 70% for farmers who had adopted CNT. Complementarities between conservation practices may enhance the benefits from adoption and allow farmers to adopt bundles of conservation practices more quickly over time. This can be taken advantage of in conservation programs by promoting or requiring practices first that enhance adoption of other practices. We also found important heterogeneity in the adoption speed associated with farm management characteristics, producers’ attitudes, weather patterns, and crop prices.

A novel localization algorithm, which considers nonline-of-sight (NLOS) propagation, is proposed in this paper. By introducing a transfer function that relates the field at a given receiver to the source as a function of frequency and position, the NLOS effect can be mitigated and the propagation channel can be calibrated back to free space. The simulation results demonstrate that the proposed algorithm performs much better than that using the usual line-of-sight time difference of arrival (TDOA) localization, and the accuracy is only limited by the sampling frequency. The measurements verify the improvement in using the improved TDOA method versus the usual TDOA method.

It is well-known that a slotted resonant cavity with high-quality factor exhibits interior electromagnetic (EM) fields that may be even larger than the external field. The authors aim to reduce the cavity's EM fields and quality factor over a frequency band analytically, numerically, and experimentally by introducing microwave absorbing materials in the cavity. A perturbation model approach was developed to estimate the quality factor of loaded cavities, which is validated against full-wave simulations and experiments. Results with 78.7 mils (2 mm) thick ECCOSORB-MCS absorber placed on the inside cavity wall above and below the aperture slot (with only 0.026% cavity volume) result in a reduction of shielding effectiveness >19 dB and reductions in quality factor >91%, providing confirmation of the efficacy of this approach.

Conservation tillage offers economic and soil quality benefits, yet conventional tillage remains the prevailing system in some regions. The purpose of this study is to identify the effect of profitability factors, risk attitudes, crop rotations, and other farmer and farm characteristics on farmers’ choices to use no-till (NT), strip-till (ST) and reduced/conventional tillage (RCT) in producing dryland corn, wheat, and soybean in Kansas. The results show that factors such as crop yields, risk aversion, crop insurance, baling and grazing of crop residue, crop acreage, and farmers’ approach to adopting new technologies are significant factors in farmers’ choice of tillage practice.

Over the past few decades, farmers have increasingly integrated cover crops into their cropping systems. Cover-crop benefits can help a farmer to achieve sustainability or reduce negative environmental externalities, such as soil erosion or chemical runoff. However, the impact on farm economics will likely be the strongest incentive to adopt cover crops. These impacts can include farm profits, cash crop yields or both. This paper provides a review of cover-crop adoption, production, risk and policy considerations from an economic perspective. These dimensions are examined through a review of cover-crop literature. This review was written to provide an overview of cover crops and their impacts on the farm business and the environment, especially with regard to economic considerations. Through increasing knowledge about cover crops, the intent here is to inform producers contemplating adoption and policy makers seeking to encourage adoption.

Many Black gay and bisexual men (BGBM) practice consistent religious worship and spirituality in order to cope with social challenges. This study utilized data from in-depth qualitative interviews conducted to explore personal meanings of religiosity and spirituality and how these constructs affect partner choices and sexual behaviors among BGBM. Interviews were conducted with 26 BGBM in Los Angeles, California, from September to November 2015. In-depth interviews yielded themes related to BGBM’s understanding of religiosity and spirituality and how their personal beliefs influenced their partner choices and sexual risks. Implications for church-based and community-based interventions are discussed.

Dedicated annual sorghum crops, such as sweet sorghum or energy sorghum, may provide an option for farmers to supply cellulosic feedstocks for biofuel production and help the industry meet government mandates. Kansas farmers are poised to be major producers of sweet sorghum for biofuels due to favorable agro-ecological conditions. The purpose of this paper is to assess Kansas farmers' willingness to grow sweet sorghum under contract as a feedstock for biofuel production. The paper examines farmers' willingness-to-pay for contract attributes and the impact of socio-economic factors on their willingness-to-pay for these attributes. A stated choice survey was administered to Kansas farmers to assess their willingness to grow sweet sorghum for biofuels under various contracting scenarios. Results show that farmers may be willing to grow biomass for bioenergy under contract, but may have varying preferences for the importance of contract attributes such as net returns, contract length, insurance availability, government incentives, and potential for biorefinery harvest options based on socio-economic characteristics of growers.

This paper examines the likelihood that farm managers would be willing to harvest crop residue, or grow a dedicated annual or perennial bioenergy crop. In addition, factors affecting how many initial acres adopters would be willing to plant of a dedicated annual or perennial bioenergy crop are assessed. The study finds several factors affect farm managers' decisions to harvest crop residue, or grow annual or perennial bioenergy crops, as well as their potential initial acreage allocation decisions. These factors lead to several policy implications that should be tailored to the specific type of cellulosic bioenergy crop.

Farmers' adoption of cellulosic biofuel feedstock enterprises plays an important role in the future of agriculture and the renewable fuels \industry. However, no set markets currently exist for bioenergy feedstocks outside of very localized geographic locations and farmers may be reluctant to produce the feedstocks without contracts that help mitigate uncertainty and risk. This study examines farmers' willingness to grow switchgrass under contract using a stated choice approach. Data were collected using an enumerated survey of Kansas farmers and analyzed using latent class logistic regression models. Farmers whose primary enterprise is livestock are less inclined to grow switchgrass. Shorter contracts, greater harvest flexibility, crop insurance, and cost-share assistance increase the likelihood that farmers will grow switchgrass for bioenergy production.

Switchgrass ( L.) has been promoted as a potential feedstock for cellulosic biofuel in the United States. Switchgrass is known to respond to N fertilizer, but optimal rates remain unclear. Given the potential nonlinear response of nitrous oxide (NO) emissions to N inputs, N additions to switchgrass above optimal levels could have large impacts on the greenhouse gas balance of switchgrass-based biofuel. Additionally, N additions are likely to have large impacts on switchgrass production costs. Yield, N removal, and net returns were measured in switchgrass receiving 0 to 200 kg N ha in Manhattan, KS, from 2012 to 2014. Emissions of NO were measured in the 0- to 150-kg N ha treatments. Total emissions of NO increased from 0.2 to 3.0 kg NO-N ha as N inputs increased from 0 to 150 kg N ha. The 3-yr averages of fertilizer-induced emission factors were 0.7, 2.1, and 2.6% at 50, 100, and 150 kg N ha, respectively. Removal of N at harvest increased linearly with increasing N rate. Switchgrass yields increased with N inputs up to 100 to 150 kg N ha, but the critical N level for maximum yields decreased each year, suggesting that N was being applied in excess at higher N rates. Net returns were maximized at 100 kg N ha at both a high and low urea cost (US$394.71 and $945.91 ha, respectively). These results demonstrate that N inputs were necessary to increase switchgrass productivity, but rates exceeding optimal levels resulted in excessive NO emissions and increased costs for producers.

Experiences of coerced or forced sex have been associated with risk for HIV infection for all adults and may be more common for gays, lesbians, bisexuals (GLB) and people who inject drugs (PWID). In this study, we explored factors associated with prior 12-month experiences of forced or coerced sex among a sample of PWID, with a focus on sexual orientation and gender. PWID (N = 772) from Los Angeles and San Francisco were recruited using targeted sampling methods in 2011–2013 and surveyed on a range of items related to demographics, drug use, HIV risk, and violence, including experiences of forced or coerced sex in the prior 12 months. In this racially/ethnically diverse, mostly homeless, and low-income sample of PWID, 25% of participants were female and 15% identified as GLB. Sexual coercion was reported by 9% of gay and bisexual men, 8% of heterosexual females, 5% of lesbians and bisexual women, and less than 1% of heterosexual men. In multivariate analyses, compared to heterosexual males, gay or bisexual males (adjusted odds ratio [AOR] = 10.68; 95% confidence interval [CI] = 2.03, 56.23), and heterosexual females (AOR = 9.69; 95% CI = 2.04, 45.94) had increased odds of coerced sex in the prior 12 months. Having a paying sex partner (AOR = 3.49; 95% CI = 1.42, 8.54) or having had forced sex prior to the age of 16 by someone at least five years older (AOR = 4.74; 95% CI = 1.88, 11.93) also elevated the odds of coercive sex. Sexual coercion is common among PWID, but especially for gay and bisexual men and heterosexual females. Efforts to reduce sexual violence among PWID are urgently needed.

The analysis of electromagnetic coupling in nonlinear circuit simulations requires a bidirectional, fully consistent approach. Nonlinear responses of semiconductor devices in electronic circuit components can change the impedances seen at circuit nodes, changing the boundary conditions encountered by impressed electromagnetic fields and, thus, changing the characteristics of the energy coupled from these external fields into that circuit. It is important to include the coupling in the circuit simulation self-consistently because this allows us to accurately predict the responses to various EMI/EMC problems of interest. It is also important to predict circuit responses efficiently because that opens the door to statistical applications for the technique being used. In this paper, we review a technique that we have developed called A Thevenin Equivalent Network Approach. This approach is shown to be quite robust in that it is computationally efficient; it can be implemented in a variety of commonly available circuit solving codes; it already includes a few additional techniques required to enhance its implementation in those codes; and it is quite accurate.

The analysis of electromagnetic coupling in nonlinear circuits requires a bidirectional, fully consistent approach. Nonlinear responses of semiconductor devices in electronic circuit components can change the impedances seen at circuit nodes, changing the boundary conditions encountered by impressed electromagnetic fields, and thus changing the characteristics of the energy coupled from these external fields into that circuit. It is important to include the coupling in the circuit simulation self-consistently because this allows us to accurately predict the responses to various EMI/EMC problems of interest. It is also important to predict circuit responses efficiently because that opens the door to statistical applications for the technique being used. In this paper, we review a technique that we have developed called ATHENA (A THevenin Equivalent Network Approach). This approach is shown to be quite robust in that it is computationally efficient, it can be implemented in a variety of commonly available circuit solving codes, it already includes a few additional techniques required to enhance its implementation in those codes, and it is quite accurate.

Many studies have assessed the technical feasibility of producing bioenergy crops on agricultural lands. However, while it is possible to produce large quantities of agricultural biomass for bioenergy from lignocellulosic feedstocks, very few of these studies have assessed farmers’ willingness to produce these crops under different contracting arrangements. The purpose of this paper is to examine farmers’ willingness to produce alternative cellulosic biofuel feedstocks under different contractual, market, and harvesting arrangements. This is accomplished by using enumerated field surveys in Kansas with stated choice experiments eliciting farmers’ willingness to produce corn stover, sweet sorghum, and switchgrass under different contractual conditions. Using a random utility framework to model the farmers’ decisions, the paper examines the contractual attributes that will most likely increase the likelihood of feedstock enterprise adoption. Results indicate that net returns above the next best alternative use of the land, contract length, cost share, financial incentives, insurance, and custom harvest options are all important contract attributes. Farmers’ willingness to adopt and their willingness-to-pay for alternative contract attributes vary by region and choice of feedstock.

Erosion of agricultural cropland has been identified as a major source of sediment accumulating in water reservoirs. Emphasis is increasingly on finding the most cost-effective ways to control soil erosion to reduce reservoir sedimentation. In this study, biophysical and economic models for the Tuttle Creek Lake watershed in northeastern Kansas were integrated to determine if implementation of alternative cropland management strategies to reduce reservoir sediment are more cost-effective than dredging. In the Tuttle Creek Lake watershed, we found that if the marginal costs of agricultural best management practices (BMP) implementation become >$6.90/t of sediment reduction, then dredging becomes the economically preferred alternative. Meeting this cost requires that BMP in the form of filter strips and no-till cultivation are implemented in a targeted, cost-effective manner, not in a random pattern of voluntary adoption that may characterize BMP adoption in some watersheds. Although reservoir dred...

A novel source localization algorithm that combines the time difference of arrival (TDOA) method and a technique for the de-embedding of the propagation transfer function for non-line-of-sight (NLOS) propagation is proposed, in order to achieve accurate source localization under NLOS conditions. An iterative implementation of the method is given, and results are shown for a simple case of a single wall obstacle.

The economic feasibility of soybeans, grain sorghum, and corn in annual rotation with winter wheat using reduced tillage and no-tillage systems in the Central Great Plains was evaluated, with continuous wheat and grain sorghum also analyzed. Net returns were calculated using simulated yield and price distributions based on historical yields, two historical annual price series, and 2011 costs. Stochastic Efficiency with Respect to a Function was used to determine the preferred strategies under various risk preferences. The no-till wheat-soybean and reduced-till wheat-soybean systems are the first and second most preferred, regardless of the level of risk aversion.

“Watershed Manager” is a spreadsheet-based model that is used in extension education programs for learning about and selecting cost-effective watershed management practices to reduce soil, nitrogen, and phosphorus losses from cropland. It can facilitate Watershed Restoration and Protection Strategy (WRAPS) stakeholder groups’ development of comprehensive watershed management plans that are required to be eligible for state and federal funding. This tool was developed to educate stakeholders about alternative best management practices (BMPs) that result in improvements in water quality and to select the combination of BMPs that yield the largest improvement in water quality per dollar spent. Users are able to estimate, optimize, and compare the economic and environmental effects of alternative management practices. WRAPS represents a citizen/stakeholder-led approach rather than a government-mandated and directed approach to watershed management. Kansas WRAPS is a state-sanctioned process whereby watershed protection and restoration plans are created and implemented. Funds, guidance, and technical assistance are provided for stakeholders to reach consensus on issues of relevance in their watershed and to design and execute a plan to address those issues. Cost-effective conservation is a way of getting the largest benefit for the dollars invested, but it is not always the most politically or socially palatable approach. Watershed Manager allows local stakeholders to cost-effectively identify politically and socially acceptable management practices. Watershed Manager has been utilized in developing cost-effective implementation plans to meet total maximum daily loads (TMDLs) for 16 Hydrologic Unit Code 8 (HUC 8) watersheds in Kansas through the WRAPS program.

This paper studies the time-domain propagation and dispersion of a pulse propagating on a microstrip line with a metallic top cover. A gap voltage source is used to model a practical excitation on the line. High-frequency distortion effects are observed that cannot be accounted for by conventional transmission-line theory, since they are due to the simultaneous excitation of the bound mode and a strong leaky mode. The bound-mode and leaky-mode components of the pulse are identified and separately studied to aid in the physical interpretation of the pulse distortion. The excitation of a dominant leaky mode gives rise to an interesting pulse-splitting phenomenon, due to the different velocities of the bound mode and the leaky mode. The influence of dielectric and conductor losses on the pulse shape is also studied.

This study examines the economic potential of producing a wheat (Triticum aesitivum) and grain sorghum (Sorgbum bicolor (L.) Moench) rotation with three different tillage strategies (conventional, reduced, and no tillage) compared with the Conservation Reserve Program (CRP) in a semiarid region. This research uses enterprise budgeting and stochastic efficiency with respect to a function to determine the preferred management strategies under various risk preferences. Yields, input rates, and field operations from an experimental field in western Kansas are used to calculate net returns for each tillage strategy. Although net returns to crop production using reduced tillage and no-tillage strategies with average crop prices for January 2007 through December 2008 are higher than CRP payments, risk analysis indicates that CRP would be the preferred strategy for more risk-averse managers. When average crop prices for January 2006 through December 2008 are used, CRP payments are higher than returns from crop production. Based on this analysis, only individuals who are risk-neutral or slightly risk-averse would prefer crop production to continue CRP enrollment in this region unless commodity prices reach the historically high levels of late 2007 and early 2008 and remain there.

T he potential for sequestering carbon in agricultural and forestry sinks to generate carbon credits has received increased attention by legislative bodies, government and nongovernment organizations, private firms, farm managers, and universities over the last few years. This increased interest is primarily due to international regulation of greenhouse gas (GHG) emissions under the Kyoto Protocol. Although the United States has not ratified the Kyoto Protocol, a voluntary market and many state and regional initiatives have been developed to reduce atmospheric concentrations of GHGs. In addition, recent legislation proposed within the United States promotes a cap-and-trade system for reducing GHGs (Pew Center 2008; RFF 2008). Since our first examination of fledging carbon credit markets and factors affecting them (Williams et al. 2005), many new markets have developed, as well as new opportunities to reduce GHG emissions. Several countries have developed GHG markets to help meet their mandatory GHG reductions under the Kyoto Protocol or other regulations. In addition, voluntary markets have formed outside the regulatory constraints to serve businesses interested in trading carbon credits, and there are a number of carbon offset providers that sell offsets to consumers and businesses. Table 1 summarizes the main market types that exist at present. The…

The input impedance and radiation pattern of the inset-fed rectangular microstrip patch antenna are investigated. It is concluded that a shifted cosine-squared function describes well the variation of the resonant input resistance with the feed location (point of contact between the microstrip feed line and the notch) for a given patch and substrate geometry. The parameters of the shifted cosine-squared function depend on the notch width for a given patch and substrate geometry. The cross-polarization level is seen to increase as either the notch width or depth increases. However, for a fixed input resistance level, the notch depth decreases as the width increases, so that the cross-polarization level is not very sensitive to the notch width for a fixed input resistance.

The electrical characteristics of an inverted shorted annular-ring-reduced surface-wave (RSW) antenna are presented in this letter. This microstrip antenna is designed for RSW excitation and lateral radiation and, hence, the characteristic patterns are relatively smooth in the forward region and demonstrate significantly reduced backscattered radiation, relative to a conventional microstrip patch. Results from a theoretical analysis of the antenna will be presented, along with confirming experimental results. These results include a radiation, input impedance, efficiency, bandwidth, directivity, and gain characterization of the antenna.

Writers carefully include critical information in the opening lines of their chapters, but students often gloss over these beginning sentences, missing information that could help them better comprehend the text. To address this concern, the authors created a strategy that prompts students to examine the opening lines of chapters, helping readers notice and name what is seen, thus deepening their understanding and engagement. This article describes the Chapter Glancing strategy, showing teachers how to lift up the opening lines of chapters to help students examine the information embedded there. The strategy prompts students to predict and infer as they notice and name aspects of the text that hold promise for future understandings. By illuminating what readers do, Chapter Glancing becomes a useful strategy that students transfer into their own reading. How to introduce this strategy to students and the variations for using this strategy are addressed.

A new Global Positioning System (GPS) microstrip patch antenna designed for dual-band (LI /L2) operation is introduced. The antenna design is based on the reduced-surface-wave (RSW) concept and, as a result, is much less susceptible to low-angle multipath interference effects than some of the more commonly-used high-precision GPS antennas. In this paper, the radiation characteristics of this new design was compared to a dual- band choke-ring and a dual-band pinwheel antenna. In addition to having the advantages typically associated with microstrip patch antennas, this planar dual-band antenna lacks the design complications associated with the frequently-used stacked-patch method for realizing dual-band microstrip antenna performance. Thus, the simplicity of the design, together with the reduced horizon and backside radiation levels and excellent circular polarization characteristics indicate that this new antenna design is a promising candidate for dual-band, high-precision applications.

Sexual positioning practices among men who have sex with men (MSM) have not received a thorough discussion in the MSM and HIV literature, given that risks for acquiring or transmitting HIV and STIs via condomless anal sex vary according to sexual positioning. MSM bear a disproportionate burden of HIV compared to the general population in the United States; surveillance efforts suggest that HIV and STIs are increasing among domestic and international populations of MSM. We conducted a narrative review, using a targeted literature search strategy, as an initial effort to explore processes through which sexual positioning practices may contribute to HIV/STI transmission. Peer-reviewed articles were eligible for inclusion if they contained a measure of sexual positioning identity and/or behavior (i.e. “top,” “bottom,” etc.) or sexual positioning behavior (receptive anal intercourse [RAI] or insertive anal intercourse [IAI]), or assessed the relationship between sexual positioning identity with HIV risk, anal sex practice, masculinity, power, partner type, or HIV status. A total of 23 articles met our inclusion criteria. This review highlights dynamic psycho-social processes likely underlying sexual decision-making related to sexual positioning identity and practices among MSM and MSM who have sex with women (MSMW), and ways these contexts may influence HIV/STI risk. Despite limited focus in the extant literature, this review notes the important role contextual factors (masculinity stereotypes, power, partner type, and HIV status) likely play in influencing sexual positioning identity and practices. Through this review we offer an initial synthesis of the literature describing sexual positioning identities and practices and conceptual model to provide insight into important areas of study through future research.

The time difference of arrival (TDOA) positioning method is a classic method that is used to determine the unknown location of a transmitting wireless device, based on the time differences in the signals that are received at different receivers. In this investigation the method is studied for two-dimensional (2-D) problems for simplicity, using a vertical dipole source radiating a carrier wave that is modulated by a baseband signal. By maximizing the cross-correlation between the signals arriving at any two receivers, the TDOA between these two receivers is estimated. In principle, only three receivers are needed for source localization in 2-D problems in the absence of noise, using the TDOA between any two pairs of receivers. However, the accuracy can be influenced significantly by non-line-of-sight effects when multiple walls, realistic ground effects, and scattering objects are added to the propagation route. A more accurate result can be obtained by using a modified method discussed here, which incorporates a transfer function that relates the field at a given receiver to the dipole source amplitude as a function of frequency. A “processed signal” is calculated at each receiver by de-embedding the transfer function from the received signals and multiplying back by a free-space propagation term for each frequency in the signal spectrum, thus removing the effects of the environment and calibrating the channel back to free space. Since the transfer function is different at each possible source position, an iterative method is proposed to do the localization.

Increasing the number of antennas for wireless communications, while concealing them within their environment, is an area of great importance as demand for wireless devices increases. One method to achieve this goal is to use the existing conducting objects in an environment as antennas. This requires altering the natural current distribution on conducting objects such that optimal radiation properties can be obtained. In this paper, a composite dielectric bead element is introduced for this purpose on electrically large wire structures. The operation of the bead element is described using transmission line theory, and a wire model of the element is given. Using the wire model, the loading for several electrically large wire structures is designed such that they resonate and radiate similarly to a half-wavelength dipole

This study examined the economic potential of no-tillage versus conventional tillage to sequester soil carbon by using two rates of commercial N fertilizer or beef cattle manure for continuous corn (Zea mays L.) production. Yields, input rates, field operations, and prices from an experiment were used to simulate a distribution of net returns for eight production systems. Carbon release values from direct, embodied, and feedstock energies were estimated for each system, and were used with soil carbon sequestration rates from soil tests to determine the amount of net carbon sequestered by each system. The values of carbon credits that provide an incentive for managers to adopt production systems that sequester carbon at greater rates were derived. No-till systems had greater annual soil carbon gains, net carbon gains, and net returns than conventional tillage systems. Systems that used beef cattle manure had greater soil carbon gains and net carbon gains, but lower net returns, than systems that used commercial N fertilizer. Carbon credits would be needed to encourage the use of manure-fertilized cropping systems.

General formulas for a two-dimensional (2-D) leaky-wave antenna (LWA) are obtained, which are applicable to any general class of 2-D leaky-wave antenna that consists of a partially reflecting surface that is mounted on top of a grounded substrate, and excited by a simple source. Closed-form expressions are obtained for the radiated fields, the field peak values in the E- and H-planes, the beamwidths in the E- and H-planes, and the pattern bandwidth. The formulas are obtained from a simple transverse equivalent network model of the structure. An accurate formula for the substrate thickness necessary to give a beam at any desired angle is also obtained.

The far-field radiation patterns of a two-dimensional (2-D) periodic slot leaky-wave antenna (LWA) are studied. The antenna consists of a two-dimensional periodic array of slots in a conducting plane that is printed on top of a grounded dielectric slab. The antenna is excited by a simple source such as a dipole inside the slab. Reciprocity along with the spectral-domain method is used to calculate the far-field pattern, and the radiation characteristics of the structure are investigated. A comparison between the present periodic slot LWA and a 2-D periodic patch LWA discussed in Part I is given to show the advantages of the slot antenna for certain applications. The slot LWA can achieve high directivity patterns, and a circularly-polarized version of the antenna can achieve good circular-polarization at broadside.

Four different models for the probe inductance of a circular probe in an infinite parallel plate waveguide are studied. These models include a uniform-current model, a cosine-current model, a gap-voltage source model, and a coaxial-frill model. These different models treat the vertical variation of the fields within the substrate and the field of the coaxial feed with varying degrees of rigor. Numerical high frequency structure simulator data are also compared with the results of these models in order to draw reliable conclusions about the accuracy of these models as a function of the substrate thickness. A simple computer-aided design formula for the probe inductance of a coaxial feed probe for a rectangular microstrip patch antenna is also introduced.

Farm machinery is a vital part of most farming operations, from the physical work it performs in the production process to the enjoyment provided from its operation. As technological advancements in machinery and the crop production process evolve, farm sizes increase and profit margins often decrease. Therefore, efficient use of machinery and its contribution to a producer’s relative cost of production is increasingly important. Machinery costs can be determined from farm records or cost estimators; however, these methods often result in generalized whole farm or per machine costs, rather than per unit (e.g., acre, ton, bale, etc.) machinery costs. One alternative to calculating the myriad of machinery costs is to use custom farming rates. Custom farming rates are rates paid for an operator to perform an operation, such as harvesting, planting, tillage, etc., and are usually based on a per unit charge (i.e. acre, ton, bales, etc.). However, with the large amount of neighbor-to-neighbor work, and family custom farming done, whether published custom rates truly represent full machinery ownership and operating costs is often questioned. If the full cost to perform these operations is known, it will allow an individual farm to evaluate its relative machinery costs and allow its crop machinery costs to be benchmarked against an expected cost.