Temperature distribution in an aircraft tire at low ground speeds

An experimental study was conducted to define temperature profiles of 22 x 5.5, type 7, bias ply aircraft tires subjected to freely rolling, yawed rolling, and light braking conditions. Temperatures along the inner wall of freely rolling tires were greater than those near the outer surface. The effect of increasing tire deflection was to increase the temperature within the shoulder and sidewall areas of the tire carcass. The effect of cornering and braking was to increase the treat temperature. For taxi operations at fixed yaw angles, temperature profiles were not symmetric. Increasing the ground speed produced only moderate increases in tread temperature, whereas temperatures in the carcass shoulder and sidewall were essentially unaffected

Some effects of adverse weather conditions on performance of airplane antiskid braking systems

The performance of current antiskid braking systems operating under adverse weather conditions was analyzed in an effort to both identify the causes of locked-wheel skids which sometimes occur when the runway is slippery and to find possible solutions to this operational problem. This analysis was made possible by the quantitative test data provided by recently completed landing research programs using fully instrumented flight test airplanes and was further supported by tests performed at the Langley aircraft landing loads and traction facility. The antiskid system logic for brake control and for both touchdown and locked-wheel protection is described and its response behavior in adverse weather is discussed in detail with the aid of available data. The analysis indicates that the operational performance of the antiskid logic circuits is highly dependent upon wheel spin-up acceleration and can be adversely affected by certain pilot braking inputs when accelerations are low. Normal antiskid performance is assured if the tire-to-runway traction is sufficient to provide high wheel spin-up accelerations or if the system is provided a continuous, accurate ground speed reference. The design of antiskid systems is complicated by the necessity for tradeoffs between tire braking and cornering capabilities, both of which are necessary to provide safe operations in the presence of cross winds, particularly under slippery runway conditions

Static and yawed-rolling mechanical properties of two type 7 aircraft tires

Selected mechanical properties of 18 x 5.5 and 49 x 17 size, type 7 aircraft tires were evaluated. The tires were subjected to pure vertical loads and to combined vertical and lateral loads under both static and rolling conditions. Parameters for the static tests consisted of tire load in the vertical and lateral directions, and parameters for the rolling tests included tire vertical load, yaw angle, and ground speed. Effects of each of these parameters on the measured tire characteristics are discussed and, where possible, compared with previous work. Results indicate that dynamic tire properties under investigation were generally insensitive to speed variations and therefore tend to support the conclusion that many tire dynamic characteristics can be obtained from static and low speed rolling tests. Furthermore, many of the tire mechanical properties are in good agreement with empirical predictions based on earlier research

What Regional Economic Factors Drive Feedstock Cost for Cannabinoid Hemp Processors in the United States?

This study measures the importance of various regional economic and agronomic factors on a grower’s decision to cultivate cannabinoid (CBD) hemp flower in the United States, and its subsequent effect on CBD processor feedstock cost. I use real options analysis to recover the price of hemp flower required to trigger land use change from commodity crop production to hemp flower production across various scenarios endemic to different hemp producing regions. Results suggest the most important factors in determining the price required to trigger CBD floral hemp production are the expected yield of floral hemp and CBD concentrations within it. CBD processors looking to secure affordable feedstock should prioritize regions supporting these factors. Under current state policies and cultivars, the Southern United States appears to be the most likely, of current major hemp production regions, to be capable of producing low-cost floral hemp. This is due to its relatively favorable growing conditions

Uncertainty, Irreversibility, And Investment In Secondgeneration Biofuels

The present study formalizes and quantifies the importance of uncertainty for investment in a corn-stover based cellulosic biofuel plant. Using a real options model we recover prices of gasoline that would trigger entry into the market and calculate the portion of that entry trigger price required to cover cost and the portion that corresponds to risk premium. We then discuss the effect of managerial flexibility on the entry risk premium and the prices of gasoline that would trigger mothballing, reactivation, and exit. Results show that the risk premium required by plants to enter the second-generation biofuel market is likely to be substantial. The analysis also reveals that a break-even approach (which ignores the portion of entry price composed of risk premium), and the traditional Marshallian approach (which ignores the portion of entry price composed of both the risk premium and the drift rate), would significantly underestimate the gasoline entry trigger price and the magnitude of that underestimation increases as both volatility and mean of gasoline prices increase. Results also uncover a great deal of hysteresis (i.e. a range of gasoline prices for which there is neither entry nor exit in the market) in entry/exit behavior by plants. Hysteresis increases as gasoline prices become more volatile. Hysteresis suggests that, at the industry level, positive (negative) demand shocks will have a significant impact on prices (production) and a limited impact on production (prices). In combination all of these results suggest that policies supporting second generation biofuels may have fallen short of their targets because of their failure to alleviate uncertainty

Hemp Production Network Effects: Are Producers Tipped Toward Suboptimal Varietal Selection by Their Neighbors?

The 2018 farm bill removed industrial hemp from the Schedule 1 Controlled Substance List. In response, states scrambled to enact hemp legislation. Some hemp flower producers report their hemp fields were cross- pollinated by a neighbor growing a different hemp cultivar. For hemp flower crops, cross- pollination reduces cannabinoid concentration levels within the flower; these concentration levels dictate flower price. We show that in a repeated game, once a sufficiently large percentage of growers decide to plant hemp fiber/seed crops, cross-pollination forces flower growers to convert to fiber/seed to avoid the negative network externality. Over time, a stable, suboptimal Nash equilibrium of reduced flower production results. The most important factor driving this tip to reduced flower production is pollen transmission rates between fields. This factor can be effectively reduced through either an auction-style quota system directed at seed and fiber cultivars or intertemporal zoning laws that dictate when a particular cultivar can be planted. As applications for hemp growing licenses swell, cross- pollination between farmers becomes increasingly likely. If left unchecked by policy, farm-level income and rural economic development will be suppressed

Adapting network theory for spatial network externalities in agriculture: A case study on hemp cross-pollination

Growers have increasingly expressed frustration over the negative externalities created by their neighbor\u27s production practices. These spatial agricultural network problems include issues such as cross-pollination and herbicide drift. We develop novel methods for estimating parameters that allow us to adapt and apply general network diffusion models to these spatial agricultural network problems. Doing so allows us to calculate externality damage within a region and calculate cost-effective policies for alleviating that externality. We empirically illustrate, motivate, and test this approach by applying it to hemp. We find that network structure is an important factor in externality size and cost-effective policy response for spatial agricultural network problems. We also find that policies that are implemented early and proactively are more likely to be successful and cost effective than policies implemented retroactively. Finally, we find that in our application of limiting the cross-pollination damage experienced by growers of feminized hemp from non-feminized hemp growers, the most cost-effective policy is to establish a regional quota on non-feminized production combined with intertemporal cultivar spacing. This policy response will likely change across time and region as economic and network variables evolve

Sustainable Consumption Behavior in Sub-Saharan Africa: A Conceptual Framework

This paper develops a conceptual framework for investigating the adoption patterns, inhibitors, and facilitators ( PIF ) of sustainable consumption in sub-Sahara African ( SSA ) settings. Literature evidence shows paucity of empirical studies on sustainable consumption from SSA , which partly explains lack of suitable conceptual framework to guide research in this area. Also, the existing frameworks, which were developed outside SSA may not be suitable for constructing sustainable consumption behavior in SSA because of its peculiarities. The key signifi cance of this article is the potential of providing future researchers in this area with a framework to guide and manage their studies. As a conceptual article, insight was drawn from a plethora of scholarly articles in the domain of sustainable consumption and related areas. The framework is built on four key constructs—adoption patterns, inhibitors, facilitators ( PIF ), and intention. As a guide for studies from the SSA , the article includes an empirical section, which provides preliminary empirical validation for the proposed PIF conceptual framework based on a pilot test. The result from the pilot study, using structural equation modeling ( SEM ), led to positing the PIF Sustainable Consumption model, thus giving support for the PIF Conceptual Framework, which this article puts forward. In addition, the proposed PIF conceptual framework is capable of providing insight for crafting sustainability-related policies. © 2016 Wiley Periodicals, Inc

Integrating micro-algae into wastewater treatment: A review

Improving the ecological status of water sources is a growing focus for many developed and developing nations, in particular with reducing nitrogen and phosphorus in wastewater effluent. In recent years, mixotrophic micro-algae have received increased interest in implementing them as part of wastewater treatment. This is based on their ability to utilise organic and inorganic carbon, as well as inorganic nitrogen (N) and phosphorous (P) in wastewater for their growth, with the desired results of a reduction in the concentration of these substances in the water. The aim of this review is to provide a critical account of micro-algae as an important step in wastewater treatment for enhancing the reduction of N, P and the chemical oxygen demand (COD) in wastewater, whilst utilising a fraction of the energy demand of conventional biological treatment systems. Here, we begin with an overview of the various steps in the treatment process, followed by a review of the cellular and metabolic mechanisms that micro-algae use to reduce N, P and COD of wastewater with identification of when the process may potentially be most effective. We also describe the various abiotic and biotic factors influencing micro-algae wastewater treatment, together with a review of bioreactor configuration and design. Furthermore, a detailed overview is provided of the current state-of-the-art in the use of micro-algae in wastewater treatment