10,421 research outputs found
The trade-off relationship between energy use and environmental quality in US agriculture: a multiobjective linear programming analysis
Improvements of environmental quality, and energy production and conservation for present and future generations have become important goals of our society. However, improvement of one goal is in general accompanied by degradation of the other goal since energy use as well as new energy production technologies result in contamination of water and air which are vital to public health;It is assumed that policy-makers have three objectives to be minimized in U.S. agricultural crop production. The objectives are minimization of crop production and transportation costs, soil loss, and energy use in producing the given demands. An interregional linear programming model was constructed to examine changes in production patterns, resource use patterns, cost, and soil loss in response to single objectives versus multiobjectives. A partial trade-off relationship between soil loss and energy use was also derived by employing the constraint method. The model has a set of constraints and a set of activities. There are approximately 1,200 resource constraints and more than 30,000 activities in the model. The year 1990 was specified as the basis for the analysis;Decrease in energy use in U.S. crop production can be achieved by increased adoption of reduced tillage practices, a shift of crop production from irrigated land to dryland, and substitution of cropland for energy inputs. Reduction of soil erosion can be accomplished by adopting conservation tillage practices, replacing conventional tillage practices with reduced tillage practices or no-tillage practices, utilizing crop residues, and rotating row crops with sod crops. The results of two compromise solutions derived by using L(,p)-metrics suggest that the levels of energy use and costs are higher, but the level of soil loss is lower as compared to the cost minimization solution;The adjustment process of reducing energy use involves opposite forces under the minimization of soil loss. Increased adoption of reduced tillage practices undoubtedly results in a reduction of soil loss and energy use. However, shifts in crop production from the western regions to the rainfed regions and the substitution of land for energy in all regions to meet the specified demands in the model increase soil loss. The solutions on the partial trade-off curve show that the net national change in soil loss is positive as the level of energy use in endogenous crop production declines. Therefore, there exists a trade-off relationship between energy use and soil loss from the national point of view
Cooper-Pair Spin Current in a Strontium Ruthenate Heterostructure
It has been recognized that the condensation of spin-triplet Cooper pairs
requires not only the broken gauge symmetry but also the spin ordering as well.
One consequence of this is the possibility of the Cooper-pair spin current
analogous to the magnon spin current in magnetic insulators, the analogy also
extending to the existence of the Gilbert damping of the collective
spin-triplet dynamics. The recently fabricated heterostructure of the thin film
of the itinerant ferromagnet SrRuO3 on the bulk Sr2RuO4, the best-known
candidate material for the spin-triplet superconductor, offers a promising
platform for generating such spin current. We will show how such
heterostructure allows us to not only realize the long-range spin valve but
also electrically drive the collective spin mode of the spin-triplet order
parameter. Our proposal represents both a new realization of the spin
superfluidity and a transport signature of the spin-triplet superconductivity.Comment: 5 pages, 3 figure
The introduction of the new control method of plant viruses infection for organic farming
Pepper mild mosaic virus (PMMoV) and cucumber mosaic virus (CMV) are economically important viruses, which cause enormous losses by infecting various vegetable crops. worldwide. Various strategies based on the avoidance of sources of infection, control of vectors have been conventionally employed to minimize the losses caused by these viruses. These strategies, however have not been effective as control tools. We have found that the extracts of gallnuts from Quercus dentate and Rhus javanica strongly inhibit PMMoV and CMV infection. The gallnuts are plant excretion produced when irritants are released by the larvae of gall insects. They contain high amounts of tannic acid such as gallic acid and ellagic acid. Also the gallnut extracts are widely used in pharmaceuticals, food and feed additives, it is safe natural material which can be used in organic farming. Our results indicate that they are potent plant viruses inhibitors that maybe used to prevent the spread of viruses infections in the cultivating farm
PIYAS-Proceeding to Intelligent Service Oriented Memory Allocation for Flash Based Data Centric Sensor Devices in Wireless Sensor Networks
Flash memory has become a more widespread storage medium for modern wireless devices because of its effective characteristics like non-volatility, small size, light weight, fast access speed, shock resistance, high reliability and low power consumption. Sensor nodes are highly resource constrained in terms of limited processing speed, runtime memory, persistent storage, communication bandwidth and finite energy. Therefore, for wireless sensor networks supporting sense, store, merge and send schemes, an efficient and reliable file system is highly required with consideration of sensor node constraints. In this paper, we propose a novel log structured external NAND flash memory based file system, called Proceeding to Intelligent service oriented memorY Allocation for flash based data centric Sensor devices in wireless sensor networks (PIYAS). This is the extended version of our previously proposed PIYA [1]. The main goals of the PIYAS scheme are to achieve instant mounting and reduced SRAM space by keeping memory mapping information to a very low size of and to provide high query response throughput by allocation of memory to the sensor data by network business rules. The scheme intelligently samples and stores the raw data and provides high in-network data availability by keeping the aggregate data for a longer period of time than any other scheme has done before. We propose effective garbage collection and wear-leveling schemes as well. The experimental results show that PIYAS is an optimized memory management scheme allowing high performance for wireless sensor networks
Spatio-Temporal Analysis of Roadside Transportation-Related Air Quality (StarTraq 2021): A Characterization of Bike Trails and Highways in the Fresno/Clovis Area
The San Joaquin Valley is identified as an area with a high level of particulate matter (PM) in the air, reaching above the federal and state clean air standards (EPA 2019). Many of the cities in the valley are classified as the most polluted cities in the United States for both particulate matter and ozone pollution (American Lung Association, 2021). To resolve this issue, alternative forms of transportation have been considered in transportation planning. In this study, active transportation mode air quality was monitored on selected Woodward Park and Old Clovis trails and urban bike lanes. Real-time aerosol monitors, and low-cost sensors were carried in a backpack on bicycles during the sampling. Researchers collected GPS data via a portable GPS technology called Tracksticks. Driving transportation mode air quality data was acquired from the roadways within the Fresno/Clovis area, spanning six sampling routes, and during intercity trips between Fresno, Berkeley, and Los Angeles, for a total of five sampling routes. âOn-Road\u27 (outside vehicle) monitors were installed on the roof of a vehicle while âIn-Vehicleâ monitors were installed inside the vehicle for comparison with the particulate pollution levels in the two contrasting microenvironments. The results showed the following three main outcomes: (1) clear relationships exist among PMs of different sizes; (2) there were greater variations in air quality of bike trails and On-Road samples than backyard and In-Vehicle samples; (3) we observed significant differences in air quality inside and outside the vehicle while driving local and intercity roadways; and (4) the road trip to the Bay area revealed that San Joaquin Valley has increased ambient PM2.5 and black carbon (BC) levels compared to those in the Bay Area on every trip, regardless of the daily change of the air quality
- âŠ