Performance and emission characteristics of biofuel in a small-scale gas turbine engine

Performance and emissions characteristics of a 30 kW gas turbine engine burning Jet A, soy methyl ester, canola methyl ester, recycled rapeseed methyl ester, hog-fat biofuel, and their 50% (volume) blends in Jet A were studied over a range of throttle settings. The addition of biofuel resulted in a reduction in static thrust and thrust-specific fuel consumption, and increased thermal efficiency. The CO and NO emissions from the turbine were reduced with the biofuel blends. The results suggest that an optimum mixture may be found that reduces pollutant emissions while producing the desired thrust. This study demonstrates that biofuels may serve as viable supplements to petroleum-based fuels.     

Micro electric discharge milling process performance: An experimental investigation

Micro electric discharge milling (μED-milling) process is gaining lot of interest in the area of microfabrication specifically for hard to machine materials. Any complex shape can be generated with a controlled motion of cylindrical tool in a predefined path similar to conventional micromilling. In this method the material removal mechanism in tool and workpiece is complex and requires a detail study of the process parameters. Parameters such as tool rotation speed, feed rate and aspect ratio (AR) can play a vital role in μED-milling process along with the fundamental parameter such as energy. This research work aims to provide exhaustive study of parameters on material removal rate (MRR) and tool wear rate (TWR) by conducting general factorial experiments. A new method is proposed to measure the volume of material eroded from workpiece and tool with an aid of design software. The experimental result shows that the parameters have individual and combined effect on MRR and TWR. Among the parameters, tool rotation speed has a significant function in flushing away the debris to ensure stable discharge. Detailed surface morphology of the machined features has also been analyzed using scanning electron microscope (SEM). A regression analysis was carried out to establish models for MRR and TWR as a function of process parameters.     

Green synthesis,characterisation and biological studies of AgNPs prepared using Shivlingi (Bryonia laciniosa) seed extract

Green synthesis of silver nanoparticles (AgNPs) using Shivlingi (Bryonia laciniosa) seed extract was carried out. Characterisation of synthesised nanoparticles was accomplished through the optical absorption and photoluminescence spectrum, X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. The XRD analysis further confirmed the size of nanoparticles ∼15 nm. TEM images revealed homogeneous spherical ∼10 nm Bryonia extract capped AgNPs. The biological studies indicated that both Bryonia seed extract and the nanoparticles lack anti‐microbial activity; however, the nanoparticles had better cytotoxicity and total antioxidant activity. The Lethal concentration (LC)₅₀ value of water extract and the nanoparticles were found to be 1091 and 592 μg/ml, respectively. The lower LC₅₀ of nanoparticles indicates that it is more cytotoxic than the crude extract. The results indicate that the Bryonia seed is safe to be used as a medicine and the formation of their nanoparticle has further enriched the chemical reactivity, energy absorption and biological mobility.Inspec keywords: silver, nanoparticles, nanomedicine, particle size, microorganisms, cellular biophysics, nanofabrication, photoluminescence, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, Fourier transform infrared spectra, Raman spectra, antibacterial activity, biochemistryOther keywords: green synthesis, biological studies, Shivlingi seed extraction, Bryonia laciniosa, silver nanoparticles, optical absorption, photoluminescence spectrum, X‐ray diffraction, transmission electron microscopy, scanning electron microscopy, SEM, Fourier transform infrared spectroscopy, Raman spectroscopy, XRD analysis, nanoparticle size, TEM images, homogeneous spherical images, antioxidant activity, water extraction, chemical reactivity, energy absorption, biological mobility, Ag     

Trustworthy Computing under Resource Constraints with the DOWN Policy

Trustworthy computing modules like secure coprocessors (ScP) are already in extensive use today, albeit limited predominantly to scenarios where constraints on cost is not a serious limiting factor. However, inexpensive trustworthy computers are required for many evolving application scenarios. The problem of realizing inexpensive ScPs for large-scale networks consisting of low-complexity devices have not received adequate consideration thus far. We introduce two strategies toward realizing low-cost ScPs. The first is the decrypt only when necessary (DOWN) policy, which can substantially improve the ability of low-cost ScPs to protect their secrets. The DOWN policy relies on the ability to operate with fractional parts of secrets. Taking full advantage of the DOWN policy requires consideration of the nature of computations performed with secrets and even the mechanisms employed for distribution of secrets. We discuss the feasibility of extending the DOWN policy to various asymmetric and symmetric cryptographic primitives. The second is cryptographic authentication strategies which employ only symmetric cryptographic primitives, based on novel ID-based key predistribution schemes that demand very low complexity of operations to be performed by the ScP and can take good advantage of the DOWN policy.     

Global optimization for scheduling refinery crude oil operations

In this work we present an outer-approximation algorithm to obtain the global optimum of a nonconvex mixed-integer nonlinear programming (MINLP) model that is used to represent the scheduling of crude oil movement at the front-end of a petroleum refinery. The model relies on a continuous time representation making use of transfer events. The proposed algorithm focuses on effectively solving a mixed-integer linear programming (MILP) relaxation of the nonconvex MINLP to obtain a rigorous lower bound (LB) on the global optimum. Cutting planes derived by spatially decomposing the network are added to the MILP relaxation of the original nonconvex MINLP in order to reduce the solution time for the MILP relaxation. The solution of this relaxation is used as a heuristic to obtain a feasible solution to the MINLP which serves as an upper bound (UB). The lower and upper bounds are made to converge to within a specified tolerance in the proposed outer-approximation algorithm. On applying the proposed technique to test examples, significant savings are realized in the computational effort required to obtain provably global optimal solutions.     

Novel schmitt trigger based on lambda diode

A new circuit to realise a Schmitt trigger has been conceived. This circuit, which is based on the well known lambda diode, is suitable for integration using CMOS technology. It requires only three devices and is probably simpler than any other conventional Schmitt trigger circuit.     

Patient preferences for in-center intense hemodialysis

There is a lack of data on patient preferences for intense hemodialysis (IHD). In this study, we conducted a cross-sectional survey to identify patient preferences and patient-centered barriers for IHD. A questionnaire on preferences and anticipated barriers, anticipated benefits, and quality of life for three in-center IHD schedules (daytime 2 hr six times/week [DHD], nocturnal 8 hr three times/week [ND3], and nocturnal 8 hr six times/week [ND6]) was administered to 100 chronic hemodialysis patients. A majority of patients (68%) were willing to undergo DHD for symptomatic benefits or increase in survival. An increase in energy level (94%) and improvement in sleep (57%) were the most common potential benefits that would justify DHD, but only 19% would undergo DHD for an increase in survival of < or =3 years. Only 20% and 7% would consider ND3 and ND6, respectively. The most common reported barriers were inadequate time for self (50%) and family (53%), followed by transportation difficulties (53%). Most patients would undergo DHD for symptomatic or survival benefits, but not ND3 or ND6. Disruption of personal time, however, is an important consideration. Success of DHD program would depend on arrangements for transportation to dialysis unit.     

Experimental verification of failure of Amontons' law in polymeric textiles

The dynamic friction of a variety of textile materials was studied and was experimentally proven that the frictional behavior of textile materials do not obey the Amontons' basic law of friction (F/N = μ). Both woven and nonwoven materials with different fiber content and constructional features were used in the study. Results show that the dynamic friction–normal load relationship is not a straight line passing through origin. A statistical approach has been followed to prove the significance of the deviation from the Amontons' law. To the authors' best knowledge, the work reported in this article has for the first time experimentally proven the failure of Amontons' basic law of friction for polymeric textiles, using a novel approach. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3879–3885, 2004     

Axisymmetric delaminations in layered cylinders

An analytical model is developed to predict the effect of an axisymmetric delamination in a layered anisotropic cylinder under different loading conditions. Thin shell assumptions are incorporated into classical laminated shell theory to facilitate the use of the simplified Donnell equations for shell displacements. The critical loading condition under which the debond tends to propagate is predicted based on Griffith's energy balance criterion. A closed-form solution for a simplified model is shown to form the basis for the realistic problem. The effects of the individual ply thicknesses, the crack front curvature, and the axial and shear strains of the laminate reference plane are studied.

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Résumé Un modèle analytique est développé pour prédire l'effet d'une délamination axisymétrique dans le cas d'un cylindre anisotrope à plusieurs couches sous des conditions de charge différentes. On incorpore des hypothèses sur les coques minces dans la théorie des coques colaminées classiques afin de faciliter l'utilisation des équations simplifiées de Donnell pour les déplacements de la coque. La condition critique de sollicitation sous laquelle le décollement tend à se propager est prédite sur la base du critère d'équilibre d'énergie de Griffith. Une solution fermée pour un modèle simplifié apparait constituer la base d'un problème réaliste. Les effets d'épaisseur des différentes couches, la courbure du front de la fissure et les déformations axiales et de cisaillement du plan de référence de la liaison sont étudiés.

     

Hierarchically porous nanoarchitecture constructed by ultrathin CoSe2 embedded Fe-CoO nanosheets as robust electrocatalyst for water oxidation

The sluggish kinetics and high cost of the noble-metal based electrocatalyst for oxygen evolution reaction(OER)still seriously limits the efficiencies of water splitting.Herein,for the first time,we rationally design a porous hierarchical nanoarchitecture,constructed by ultrathin CoSe2 embedded Fe-CoO nanosheets(CoSe2@Fe-CoO),which is synthesized via self-assembly hydrolysis driven in-situ synergetic selenization of Fe/Co/O/Se precursor followed by Ostwald ripening.As an OER catalyst,the porous CoSe2@Fe-CoO hybrid with abundant CoOOH electroactive sites delivers a small Tafel of 56.2 mV/dec with very low onset overpotential of 280 mV@10 mA/cm2 and excellent long-term physicochemical stability till 62 h without obvious decay,which outperforms well-established benchmark electrocatalysts(RuO2).The boosted OER performance of CoSe2@Fe-CoO nanosheets is mainly attributed to its iron-doping effect,porous nanoarchitecture,and multicomponent synergetic/interfacial effect between ultrathin cobalt(Ⅱ)oxide and conductive cobalt selenide(CoSe2)nanoframework.This work presents a facile construction strategy to find a nonprecious hybrid OER electrocatalyst with excellent performance and long-term stability.