645 research outputs found
Comparative Efficiency and Driving Range of Light- and Heavy-Duty Vehicles Powered with Biomass Energy Stored in Liquid Fuels or Batteries
This study addresses the question, When using cellulosic biomass for vehicular transportation, which field-to-wheels pathway is more efficient: that using biofuels or that using bioelectricity? In considering the question, the level of assumed technological maturity significantly affects the comparison, as does the intended transportation application. Results from the analysis indicate that for light-duty vehicles, over ranges typical in the United States today (e.g., 560-820 miles), field-to-wheels performance is similar, with some scenarios showing biofuel to be more efficient, and others indicating the two pathways to be essentially the same. Over the current range of heavy-duty vehicles, the field-to-wheels efficiency is higher for biofuels than for electrically powered vehicles. Accounting for technological advances and range, there is little basis to expect mature bioelectricity-powered vehicles to have greater field-to-wheels efficiency (e.g., kilometers per gigajoule biomass or per hectare) compared with mature biofuel-powered vehicles
Health claims in the labelling and marketing of food products:: the Swedish food sector's Code of Practice in a European perspective
Since 1990 certain health claims in the labelling and marketing of food products have been allowed in Sweden within the food sector's Code of Practice. The rules were developed in close dialogue with the authorities. The legal basis was a decision by the authorities not to apply the medicinal products’ legislation to “foods normally found on the dinner table” provided the rules defined in the Code were followed. The Code of Practice lists nine well-established diet–health relationships eligible for generic disease risk reduction claims in two steps and general rules regarding nutrient function claims. Since 2001, there has also been the possibility for using “product-specific physiological claims (PFP)”, subject to premarketing evaluation of the scientific dossier supporting the claim. The scientific documentation has been approved for 10 products with PFP, and another 15 products have been found to fulfil the Code's criteria for “low glycaemic index”. In the third edition of the Code, active since 2004, conditions in terms of nutritional composition were set, i.e. “nutrient profiles”, with a general reference to the Swedish National Food Administration's regulation on the use of a particular symbol, i.e. the keyhole symbol. Applying the Swedish Code of practice has provided experience useful in the implementation of the European Regulation on nutrition and health claims made on foods, effective from 2007
Bioenergy and African Transformation
Among the world’s continents, Africa has the highest incidence of food insecurity and poverty and the highest rates of population growth. Yet Africa also has the most arable land, the lowest crop yields, and by far the most plentiful land resources relative to energy demand. It is thus of interest to examine the potential of expanded modern bioenergy production in Africa. Here we consider bioenergy as an enabler for development, and provide an overview of modern bioenergy technologies with a comment on application in an Africa context. Experience with bioenergy in Africa offers evidence of social benefits and also some important lessons. In Brazil, social development, agricultural development and food security, and bioenergy development have been synergistic rather than antagonistic. Realizing similar success in African countries will require clear vision, good governance, and adaptation of technologies, knowledge, and business models to myriad local circumstances. Strategies for integrated production of food crops, livestock, and bioenergy are potentially attractive and offer an alternative to an agricultural model featuring specialized land use. If done thoughtfully, there is considerable evidence that food security and economic development in Africa can be addressed more effectively with modern bioenergy than without it. Modern bioenergy can be an agent of African transformation, with potential social benefits accruing to multiple sectors and extending well beyond energy supply per se. Potential negative impacts also cut across sectors. Thus, institutionally inclusive multi-sector legislative structures will be more effective at maximizing the social benefits of bioenergy compared to institutionally exclusive, single-sector structures
Transport coefficients for electrolytes in arbitrarily shaped nano and micro-fluidic channels
We consider laminar flow of incompressible electrolytes in long, straight
channels driven by pressure and electro-osmosis. We use a Hilbert space
eigenfunction expansion to address the general problem of an arbitrary cross
section and obtain general results in linear-response theory for the hydraulic
and electrical transport coefficients which satisfy Onsager relations. In the
limit of non-overlapping Debye layers the transport coefficients are simply
expressed in terms of parameters of the electrolyte as well as the geometrical
correction factor for the Hagen-Poiseuille part of the problem. In particular,
we consider the limits of thin non-overlapping as well as strongly overlapping
Debye layers, respectively, and calculate the corrections to the hydraulic
resistance due to electro-hydrodynamic interactions.Comment: 13 pages including 4 figures and 1 table. Typos corrected. Accepted
for NJ
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Technoeconomic and life-cycle analysis of single-step catalytic conversion of wet ethanol into fungible fuel blendstocks
Technoeconomic and life-cycle analyses are presented for catalytic conversion of ethanol to fungible hydrocarbon fuel blendstocks, informed by advances in catalyst and process development. Whereas prior work toward this end focused on 3-step processes featuring dehydration, oligomerization, and hydrogenation, the consolidated alcohol dehydration and oligomerization (CADO) approach described here results in 1-step conversion of wet ethanol vapor (40 wt% in water) to hydrocarbons and water over a metal-modified zeolite catalyst. A development project increased liquid hydrocarbon yields from 36% of theoretical to >80%, reduced catalyst cost by an order of magnitude, scaled up the process by 300-fold, and reduced projected costs of ethanol conversion 12-fold. Current CADO products conform most closely to gasoline blendstocks, but can be blended with jet fuel at low levels today, and could potentially be blended at higher levels in the future. Operating plus annualized capital costs for conversion of wet ethanol to fungible blendstocks are estimated at 1.44/GJ in the future, similar to the unit energy cost of producing anhydrous ethanol from wet ethanol (100 per barrel but not at 60 per barrel. Life-cycle greenhouse gas emission reductions for CADO-derived hydrocarbon blendstocks closely follow those for the ethanol feedstock
Intracavity optical trapping with ytterbium doped fiber
We propose a novel approach for trapping micron-sized particles and living cells based on optical feedback. This approach can be implemented at low numerical aperture (NA=0.5, 20X) and long working distance. In this configuration, an optical tweezers is constructed inside a ring cavity fiber laser and the optical feedback in the ring cavity is controlled by the light scattered from a trapped particle. In particular, once the particle is trapped, the laser operation, optical feedback and intracavity power are affected by the particle motion. We demonstrate that using this configuration is possible to stably hold micron-sized particles and single living cells in the focal spot of the laser beam. The calibration of the optical forces is achieved by tracking the Brownian motion of a trapped particle or cell and analysing its position distribution. © 2013 SPIE
Autoantibodies against NMDAR subunit NR1 disappear from blood upon anesthesia
Anesthetics penetrate the blood-brain-barrier (BBB) and - as confirmed preclinically – transiently disrupt it. An analogous consequence in humans has remained unproven. In mice, we previously reported that upon BBB dysfunction, the brain acts as ‘immunoprecipitator’ of autoantibodies against N-methyl-D-aspartate-receptor subunit-NR1 (NMDAR1-AB). We thus hypothesized that during human anesthesia, pre-existing NMDAR1-AB will specifically bind to brain. Screening of N = 270 subjects undergoing general anesthesia during cardiac surgery for serum NMDAR1-AB revealed N = 25 NMDAR1-AB seropositives. Only N = 14 remained positive post-surgery. No changes in albumin, thyroglobulin or CRP were associated with reduction of serum NMDAR1-AB. Thus, upon anesthesia, BBB opening likely occurs also in humans
One loop photon-graviton mixing in an electromagnetic field: Part 2
In part 1 of this series compact integral representations had been obtained
for the one-loop photon-graviton amplitude involving a charged spin 0 or spin
1/2 particle in the loop and an arbitrary constant electromagnetic field. In
this sequel, we study the structure and magnitude of the various polarization
components of this amplitude on-shell. Explicit expressions are obtained for a
number of limiting cases.Comment: 31 pages, 3 figure
Evaluating of HPV-DNA ISH as an adjunct to p16 testing in oropharyngeal cancer
© 2020 Jeffrey Chi. Aim: Current guidelines recommend p16 immunohistochemistry (IHC) for testing human papillomavirus (HPV) in oropharyngeal carcinoma (OPSCC). We evaluated the value of adding DNA in situ hybridization (ISH) to p16 IHC. Methods: Fifty patients with OPSCC were analyzed. Concordance between HPV-DNA ISH and p16 IHC was measured by Gwet\u27s agreement coefficient. Results: p16 IHC was positive in 35/48 (72.9%), negative in 8/48 (16.7%) patients. Wide spectrum DNA-ISH was positive in 9/23 (39%) and negative in 14/23 (60.9%) patients. High-risk 16/18 (HR) HPV DNA-ISH was positive in 11/23 (47.8%) and negative in 12 (52.2%) patients. The agreement between HPV DNA-ISH and p16 IHC is fair (Gwet\u27s AC1 = 0.318). Conclusion: The agreement between p16 IHC and HPV-DNA ISH was fair. However, ISH sensitivity was low. Our findings add to the current data that p16 IHC testing is reliable and may be enough as a stand-alone test for HPV detection in OPSCC. Current testing guidelines recommend p16 immunochemistry (IHC) for detecting human papillomavirus (HPV) in oropharyngeal cancer (OPSCC). We evaluated the value of adding HPV DNA in situ hybridization (ISH) to p16 IHC. Fifty patients with OPSCC were analyzed. p16 IHC was positive in 72.9% of patients and DNA-ISH was positive in 39% of patients when wide spectrum probe was used and positive in 47.8% of patients when high-risk probe was used. The agreement between the two tests was fair. However, DNA-ISH sensitivity was low. p16 IHC may be enough as a stand-alone test for detection of HPV in OPSCC
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