246 research outputs found
Numerical Modelling of Biodiesel Blends in a Diesel Engine
© 2017 The Authors. Biodiesel is a biofuel which has similar properties to diesel and can readily be used in a diesel engine with minimal modifications. Promising results have been determined using mixtures of biodiesel and diesel with the reduction of soot and emissions of a diesel engine. Experimental analysis of diesel engines can be expensive and therefore Computation Fluid Dynamics programs are used to analyses the combustion process. The AVL Fire ESED program is currently being employed to investigate the effects of biodiesel on the diesel engines soot, emissions and power generation from a Cummins ISBE220 engine. Investigation is performed on pre and post injection-rate shapes on the combustion process establishing the results correlate accurately with researched data. A pre injection was determined to increase maximum power, reduce combustion generated noise, increase early in cylinder temperature and reduce fuel consumption due to the increase in power. A post injection was verified to reduce soot emissions while increasing NOx emissions marginally. The investigation of the injection-rate shape established the soot-NOx trade-off which was also found in the research. The models developed were agreeable with biodiesel data with percentage error in indicated power ranging from 1.62-8.85%. The models suggested that biodiesel assists in reducing NOx and soot emissions. The soot-NOx trade-off was further investigated determining the theory that then by reducing the combustion temperature in the combustion chamber the NOx emissions can be reduced while increasing soot emissions. By increasing the temperature in the combustion chamber the opposite effect was found to occur
Secure -dimensional Simultaneous Dense Coding and Applications
Simultaneous dense coding guarantees that Bob and Charlie simultaneously
receive their respective information from Alice in their respective processes
of dense coding. The idea is to use the so-called locking operation to "lock"
the entanglement channels, thus requiring a joint unlocking operation by Bob
and Charlie in order to simultaneously obtain the information sent by Alice. We
present some new results on simultaneous dense coding: (1) We propose three
simultaneous dense coding protocols, which use different -dimensional
entanglement (Bell state, W state and GHZ state). (2) Besides the quantum
Fourier transform, two new locking operators are introduced (the double
controlled-NOT operator and the SWAP operator). (3) In the case that spatially
distant Bob and Charlie have to finalise the protocol by implementing the
unlocking operation through communication, we improve our protocol's fairness,
with respect to Bob and Charlie, by implementing the unlocking operation in
series of steps. (4) We improve the security of simultaneous dense coding
against the intercept-resend attack. (5) We show that simultaneous dense coding
can be used to implement a fair contract signing protocol. (6) We also show
that the -dimensional quantum Fourier transform can act as the locking
operator in simultaneous teleportation of -level quantum systems.Comment: 22 pages, comments are welcom
Angiogenesis in the synovium and at the osteochondral junction in osteoarthritis
SummaryObjectivesWe hypothesised that osteochondral and synovial angiogenesis in osteoarthritis (OA) are independent processes. We investigated whether indices of osteochondral and synovial angiogenesis display different relationships with synovitis, disease severity and chondrocalcinosis in patients with OA.DesignSynovium and medial tibial plateaux were obtained from 62 patients undergoing total knee joint replacement for OA (18 [29%] had chondrocalcinosis) and from 31 recently deceased people with no evidence of joint pathology post-mortem (PM). Vascular endothelium, proliferating endothelial cells (ECs) and macrophages were quantified by immunohistochemistry for CD34, CD31/Ki67 and CD14, respectively. Grades were assigned for radiographic and histological OA disease severity, clinical disease activity and histological synovitis (based on cellular content of the synovium).ResultsBlood vessels breached the tidemark in 60% of patients with OA and 20% of PM controls. Osteochondral vascular density increased with increasing cartilage severity and clinical disease activity scores, but not with synovitis. Synovial EC proliferation, inflammation and macrophage infiltration were higher in OA than in PM controls. Synovial angiogenesis indices increased with increasing histological synovitis, but were not related to osteochondral vascular density or other indices of OA disease severity. OA changes were more severe in patients with concurrent chondrocalcinosis. Chondrocalcinosis was not associated with increased angiogenesis or histological synovitis beyond that seen in OA alone.ConclusionOsteochondral and synovial angiogenesis appear to be independent processes. Osteochondral vascularity is associated with the severity of OA cartilage changes and clinical disease activity, whereas synovial angiogenesis is associated with histological synovitis. Modulation of osteochondral and synovial angiogenesis may differentially affect OA disease
Multiplexing of encrypted data using fractal masks
This paper was published in OPTICS LETTERS and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://dx.doi.org/10.1364/OL.37.002895. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under lawIn this Letter, we present to the best of our knowledge a new all-optical technique for multiple-image encryption and multiplexing, based on fractal encrypting masks. The optical architecture is a joint transform correlator. The multiplexed encrypted data are stored in a photorefractive crystal. The fractal parameters of the key can be easily tuned to lead to a multiplexing operation without cross talk effects. Experimental results that support the potential of the method are presented.This research was performed under grants TWAS-UNESCO Associateship Scheme at Centres of Excellence in the South, CONICET No. 0863 (Argentina), ANCYT PICT 1167 (Argentina), and Facultad de Ingenieria, Universidad Nacional de La Plata No. 11/I125 (Argentina), Sostenibilidad 2011-2012, and CODI (Universidad de Antioquia-Colombia). W. D. Furlan and J. A. Monsoriua acknowledge financial support from Ministerio de Economia y Competitividad (grant FIS2011-23175), Generalitat Valenciana (grant PROMETEO2009-077), and Universitat Politecnica de Valencia (grants PAID-05-11 and PAID-02-11), Spain.Barrera, J.; Tebaldi, M.; Amaya, D.; Furlan, W.; Monsoriu Serra, JA.; Bolognini, NA.; Torroba, RD.... (2012). Multiplexing of encrypted data using fractal masks. Optics Letters. 37(14):2895-2897. doi:10.1364/OL.37.002895S289528973714Refregier, P., & Javidi, B. (1995). Optical image encryption based on input plane and Fourier plane random encoding. Optics Letters, 20(7), 767. doi:10.1364/ol.20.000767Matoba, O., & Javidi, B. (1999). Encrypted optical memory system using three-dimensional keys in the Fresnel domain. Optics Letters, 24(11), 762. doi:10.1364/ol.24.000762Unnikrishnan, G., Joseph, J., & Singh, K. (2000). Optical encryption by double-random phase encoding in the fractional Fourier domain. Optics Letters, 25(12), 887. doi:10.1364/ol.25.000887Nomura, T. (2000). Polarization encoding for optical security systems. Optical Engineering, 39(9), 2439. doi:10.1117/1.1288369Tebaldi, M., Furlan, W. D., Torroba, R., & Bolognini, N. (2009). Optical-data storage-readout technique based on fractal encrypting masks. Optics Letters, 34(3), 316. doi:10.1364/ol.34.000316Situ, G., & Zhang, J. (2005). Multiple-image encryption by wavelength multiplexing. Optics Letters, 30(11), 1306. doi:10.1364/ol.30.001306Liu, Z., & Liu, S. (2007). Double image encryption based on iterative fractional Fourier transform. Optics Communications, 275(2), 324-329. doi:10.1016/j.optcom.2007.03.039Hwang, H.-E., Chang, H. T., & Lie, W.-N. (2009). Multiple-image encryption and multiplexing using a modified Gerchberg-Saxton algorithm and phase modulation in Fresnel-transform domain. Optics Letters, 34(24), 3917. doi:10.1364/ol.34.003917Matoba, O., & Javidi, B. (1999). Encrypted optical storage with angular multiplexing. Applied Optics, 38(35), 7288. doi:10.1364/ao.38.007288Fredy Barrera, J., Henao, R., Tebaldi, M., Torroba, R., & Bolognini, N. (2006). Multiplexing encryption–decryption via lateral shifting of a random phase mask. Optics Communications, 259(2), 532-536. doi:10.1016/j.optcom.2005.09.027Henao, R., Rueda, E., Barrera, J. F., & Torroba, R. (2010). Noise-free recovery of optodigital encrypted and multiplexed images. Optics Letters, 35(3), 333. doi:10.1364/ol.35.000333Barrera, J. F., Henao, R., Tebaldi, M., Torroba, R., & Bolognini, N. (2006). Multiple image encryption using an aperture-modulated optical system. Optics Communications, 261(1), 29-33. doi:10.1016/j.optcom.2005.11.055Mosso, F., Barrera, J. F., Tebaldi, M., Bolognini, N., & Torroba, R. (2011). All-optical encrypted movie. Optics Express, 19(6), 5706. doi:10.1364/oe.19.005706Monsoriu, J. A., Saavedra, G., & Furlan, W. D. (2004). Fractal zone plates with variable lacunarity. Optics Express, 12(18), 4227. doi:10.1364/opex.12.00422
Quantum fluids of light
This article reviews recent theoretical and experimental advances in the
fundamental understanding and active control of quantum fluids of light in
nonlinear optical systems. In presence of effective photon-photon interactions
induced by the optical nonlinearity of the medium, a many-photon system can
behave collectively as a quantum fluid with a number of novel features stemming
from its intrinsically non-equilibrium nature. We present a rich variety of
photon hydrodynamical effects that have been recently observed, from the
superfluid flow around a defect at low speeds, to the appearance of a
Mach-Cherenkov cone in a supersonic flow, to the hydrodynamic formation of
topological excitations such as quantized vortices and dark solitons at the
surface of large impenetrable obstacles. While our review is mostly focused on
a class of semiconductor systems that have been extensively studied in recent
years (namely planar semiconductor microcavities in the strong light-matter
coupling regime having cavity polaritons as elementary excitations), the very
concept of quantum fluids of light applies to a broad spectrum of systems,
ranging from bulk nonlinear crystals, to atomic clouds embedded in optical
fibers and cavities, to photonic crystal cavities, to superconducting quantum
circuits based on Josephson junctions. The conclusive part of our article is
devoted to a review of the exciting perspectives to achieve strongly correlated
photon gases. In particular, we present different mechanisms to obtain
efficient photon blockade, we discuss the novel quantum phases that are
expected to appear in arrays of strongly nonlinear cavities, and we point out
the rich phenomenology offered by the implementation of artificial gauge fields
for photons.Comment: Accepted for publication on Rev. Mod. Phys. (in press, 2012
Green criminology: shining a critical lens on environmental harm
Green criminology provides for inter-disciplinary and multi-disciplinary engagement with environmental crimes and wider environmental harms. Green criminology applies a broad ‘‘green’’ perspective to environmental harms, ecological justice, and the study of environmental laws and criminality, which includes crimes affecting the environment and non-human nature. Within the ecological justice and species justice perspectives of green criminology there is a contention that justice systems need to do more than just consider anthropocentric notions of criminal justice, they should also consider how justice systems can provide protection and redress for the environment and other species. Green criminological scholarship has, thus, paid direct attention to theoretical questions of whether and how justice systems deal with crimes against animals and the environment; it has begun to conceptualize policy perspectives that can provide contemporary ecological justice alongside mainstream criminal justice. Moving beyond mainstream criminology’s focus on individual offenders, green criminology also explores state failure in environmental protection and corporate offending and environmentally harmful business practices. A central discussion within green criminology is that of whether environmental harm rather than environmental crime should be its focus, and whether green ‘‘crimes’’ should be seen as the focus of mainstream criminal justice and dealt with by core criminal justice agencies such as the police, or whether they should be considered as being beyond the mainstream. This article provides an introductory overview that complements a multi- and inter-disciplinary article collection dedicated to green criminological thinking and research
Radiotherapy following breast-conserving surgery for screen-detected ductal carcinoma in situ: indications and utilisation in the UK. Interim findings from the Sloane Project
Use of radiotherapy (RT) after breast-conserving surgery (BCS) for ductal carcinoma in situ (DCIS) varies according to country, precedent and prejudice. Results from a preliminary analysis of the data available within the UK Sloane Project can be appreciated in the context of the uncertainty concerning the selection of adjuvant RT following BCS for DCIS. There was a marked geographical variation in the use of RT within the United Kingdom. However, overall, patients with DCIS treated with BCS were significantly more likely to have RT planned (and given) if they had large (⩾15 mm), intermediate or high-grade tumours or if central comedo-type necrosis was present. Unexpectedly, margin width did not appear to have a significant effect on the decision-making process. However, the Van Nuys Prognostic Index did significantly affect the chances of getting planned RT in the univariate analysis, suggesting that clinicians may be starting to use this scoring system in routine practice to assist in decision making
Cloning and Characterization of Glutamate Receptors in Californian Sea Lions (Zalophus californianus)
Domoic acid produced by marine algae has been shown to cause acute and chronic neurologic sequelae in Californian sea lions following acute or low-dose exposure. Histological findings in affected animals included a degenerative cardiomyopathy that was hypothesized to be caused by over-excitation of the glutamate receptors (GluRs) speculated to be present in the sea lion heart. Thus tissues from five sea lions without lesions associated with domoic acid toxicity and one animal with domoic acid-induced chronic neurologic sequelae and degenerative cardiomyopathy were examined for the presence of GluRs. Immunohistochemistry localized mGluR 2/3, mGluR 5, GluR 2/3 and NMDAR 1 in structures of the conducting system and blood vessels. NMDAR 1 and GluR 2/3 were the most widespread as immunoreactivity was observed within sea lion conducting system structures. PCR analysis, cloning and subsequent sequencing of the seal lion GluRs showed only 80% homology to those from rats, but more than 95% homologous to those from dogs. The cellular distribution and expression of subtypes of GluRs in the sea lion hearts suggests that exposure to domoic acid may induce cardiac damage and functional disturbances
Environmental Justice and the Role of Criminology: An Analytical Review of 33 Years of Environmental Justice Research
An increasing number of scholars and activists have begun to tackle a variety of issues relevant to environmental justice studies. This study attempts to address the role of criminologists in this domain. The authors examine 425 environmental justice articles in 204 academic journals, representing 18 programs/departments between 1970 and 2003. First, they measure the environmental justice contributions in the literature by academic department or activist affiliation. Second, they identify the major themes in the literature as they have developed and reveal the current and future directions of environmental justice studies. Such themes include the spatial distribution of hazards, social movements, law and public policy, and environmental discrimination. Finally, the authors seek to call attention to the evident linkages between accepted areas of criminological scholarship and environmental justice. From this latter objective, the authors seek to demonstrate how criminology and criminal justice can advance this critical dialogue and social movement
Continuum of care in maternal, newborn and child health in Pakistan: analysis of trends and determinants from 2006 to 2012
Iqbal S, Maqsood S, Zakar R, Zakria Zakar M, Fischer F. Continuum of care in maternal, newborn and child health in Pakistan: analysis of trends and determinants from 2006 to 2012. BMC Health Services Research. 2017;17(1): 189.Background
Pakistan, being a developing country, presents the dismal picture of maternal and neonatal mortality and morbidity. The majority of maternal and neonatal deaths could be avoided if Continuum of Care (CoC) is provided in a structured pathway from pregnancy to birth and to the first week of life of the newborn child. This study aimed to analyse the trends of CoC at all three levels (antenatal care, skilled delivery and postpartum care) and to identify various factors affecting the continuation in receiving CoC in Pakistan during 2006 to 2012.
Methods
Secondary data analysis was performed on nationally representative data from the last two iterations of Pakistan Demographic and Health Survey (PDHS), conducted during 2006/07 to 2012/13. The analysis is limited to women of the reproductive age group (15–49 years) who gave birth during the last five years preceding both surveys. This leads to a sample size of 5,724 and 7,461 respondents from PDHS 2006/07 and 2012/13 respectively. The association between CoC and several factors, including individual attributes (reproductive status), family influences, community context, as well as cultural and social values was assessed in bivariate analyses in a first step. Furthermore, odds ratios and adjusted odds ratios with 95% confidence intervals using a binary and multivariable logistic regression were calculated.
Results
Our research presents the trends of a composite measure of CoC including antenatal care, delivery assistance and postpartum care. The largest gap in CoC was observed at antenatal care followed by delivery and postnatal care within 48 h after delivery. Results show that CoC completion rate has increased from 15% to 27% amongst women in Pakistan over time from 2006 to 2012. Women with high age at first birth, having less number of children, with higher education, belonging to richest quintile, living in Sindh province and urban areas, having high autonomy and exposure to mass media were most likely to avail complete CoC.
Conclusions
The findings show that women in Pakistan still lack the CoC. This calls for attention to develop and implement tailored interventions, focusing on the needs of women in Pakistan to provide CoC in an integrated manner, involving both public and private sectors by appropriately addressing the factors hindering CoC completion rates
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