Injection Apparatus Research Articles

Development and performance assessment of the new-generation CF fuel injection system for diesel passenger cars

An innovative hydraulic layout for high-pressure fuel injection systems has been developed. The rail has been removed from the high-pressure circuit of standard Common Rail injection apparatus in order to have: reduced production costs, easy installation on the engine and a fast dynamic response of the injection system during engine transients. The innovative high-pressure pump has been machined with extra delivery ports in order to obtain direct connection with each of the injector feeding pipes. A special pump delivery-chamber, featuring an adequate volume, was designed to provide the minimum hydraulic capacitance required for a proper control of the high-pressure in the system. A prototype of the new-concept Common Feeding (CF) injection system was set up at the Politecnico di Torino laboratory and subjected to an extensive experimental campaign on an advanced hydraulic test rig. The hydraulic performance of the new apparatus was compared with that of standard Common Rail system, in terms of injected flow-rate time histories, cycle-to-cycle dispersion and multiple injection dependence on dwell time. Finally, the new-generation system was installed on a Euro 5 diesel engine and tested in a dynamometer-cell. Pollutant emissions were measured at some reference working conditions as well as along the NEDC and compared to analogous data obtained for the same engine, but set up applying the standard Common Rail.

Flow Injection Analysis of Ethambutol in Antituberculosis Drugs Using a Graphite‐Paraffin Electrode as Amperometric Detector

AbstractA graphite‐paraffin composite electrode has been used for the determination of ethambutol, an antituberculosis drug, in pharmaceutical samples by anodic oxidation. Voltammetric studies were used to characterise the electrochemical behaviour of the ethambutol in different pH solutions (3.0, 8.0 and 12.0). Quantification was carried out using amperometric detection. The detector was assembled in a flow injection apparatus and operated at +1.1 V (vs. Ag/AgCl(NaCl,sat)). The conditions for the best electrode’s response were determined by studying the influence of sample volume and flow rate. The linear response for the method was extended up to a 1.5 mmol L−1 ethambutol solution with a detection limit of 0.1 mmol L−1. The repeatability for successive injections of 1.0 mmol L−1 ethambutol solution was 0.9 % (n=26), demonstrating a good performance of the developed amperometric sensor. The analytical frequency was calculated as approximately 47 determinations h−1. Two different commercial samples were successfully analysed and the results were in good agreement with those obtained by using spectrophotometry. The advantages of the proposed amperometric method over the reference method include simplicity, low consumption of reagents and increased analytical frequency.

Molten Salt Synthesis of Forsterite Heat Insulation Material

The forsterite thermal insulation materials were prepared by the molten salt method and using natural forsterite and NaCl-Na2CO3 molten salt as raw materials. The influences of different mass ratios and reaction temperatures on thermal insulation materials were investigated. Apparent porosity, bulk density and compressive strength of the samples were characterized. And the pore size distribution and microstructure were analyzed by mercury injection apparatus and scanning electron microscopy. The results demonstrated that when the sample was sintered at 1100 °C, and the content of molten salt was 40 wt%, the forsterite thermal insulation materials were better with high apparent porosity and certain compressive strength. The distribution of the pore size was very uniform. Molten NaCl provided liquid environment promoted the sintered of forsterite, the pore was received after the NaCl was removed and the decomposition of Na2CO3.

A membrane-based immunosensor for the analysis of the herbicide isoproturon

A membrane based heterogeneous competitive enzyme-linked immunosorbent assay (ELISA) was used in this work to develop an immunosensor for the detection of a common herbicide, isoproturon. A screen-printed carbon working electrode with carbon counter and silver–silver chloride pseudo-reference electrode was utilized incorporating a membrane fixed into intimate contact with the working electrode to facilitate signal transduction. The membrane containing an immobilized isoproturon–ovalbumin conjugate was laminated onto the carbon working electrode and horseradish peroxidase (HRP) labeled polyclonal antibody was then applied for the competitive assay. Two different amperometric systems, hydroquinone and o-phenylenediamine (OPD) mediation reduction were utilised and the properties of the resultant sensors were compared. A flow injection apparatus was also developed utilising the immunosensor. Limits of detection for isoproturon (LLD 90) were found to be as low as 0.84 ng mL −1. The senor was also validated using spiked extracted soil samples and also isoproturon contaminated samples.

Yersinia enterocolitica outer protein T (YopT)

Pathogenic Yersinia strains evade the innate immune responses of the host by producing effector proteins ( Yersinia outer proteins (Yops)), which are directly injected into mammalian cells by a type III secretion system (TTSS). One of these effector proteins (YopT) disrupts the actin cytoskeleton of the host cell. YopT is a cysteine protease which cleaves Rho proteins directly upstream of the post-translationally modified cysteine. Thereby, it releases the GTPases from the membrane leading to their inactivation. Besides a biochemical characterisation of the molecular mechanism and substrate specificity also delivery into host cells with chaperone binding and guidance to the injection apparatus and the patho-physiological role of YopT have been studied and are summarised in this review.

Cleavage of the NF-κB Family Protein p65/RelA by the Chlamydial Protease-like Activity Factor (CPAF) Impairs Proinflammatory Signaling in Cells Infected with Chlamydiae

Chlamydiae are obligate intracellular bacteria that frequently cause human disease. Chlamydiae replicate in a membranous vacuole in the cytoplasm termed inclusion but have the ability to transport proteins into the host cell cytosol. Chlamydial replication is associated with numerous changes of host cell functions, and these changes are often linked to proteolytic events. It has been shown earlier that the member of the NF-κB family of inflammation-associated transcription factors, p65/RelA, is cleaved during chlamydial infection, and a chlamydial protease has been implicated. We here provide evidence that the chlamydial protease chlamydial protease-like activity factor (CPAF) is responsible for degradation of p65/RelA during infection. This degradation was seen in human and in mouse cells infected with either Chlamydia trachomatis or Chlamydia pneumoniae where it correlated with the expression of CPAF and CPAF activity. Isolated expression of active C. trachomatis or C. pneumoniae CPAF in human or mouse cells yielded a p65 fragment of indistinguishable size from the one generated during infection. Expression of active CPAF in human cells caused a mild reduction in IκBα phosphorylation but a strong reduction in NF-κB reporter activity in response to interleukin-1β. Infection with C. trachomatis likewise reduced this responsiveness. IL-1β-dependent secretion of IL-8 was further reduced by CPAF expression. Secretion of CPAF is, thus, a mechanism that reduces host cell sensitivity to a proinflammatory stimulus, which may facilitate bacterial growth in vivo.

Visualizing the Structural Changes of Bacteriophage Epsilon15 and Its Salmonella Host during Infection

The efficient mechanism by which double-stranded DNA bacteriophages deliver their chromosome across the outer membrane, cell wall, and inner membrane of Gram-negative bacteria remains obscure. Advances in single-particle electron cryomicroscopy have recently revealed details of the organization of the DNA injection apparatus within the mature virion for various bacteriophages, including epsilon15 (ɛ15) and P-SSP7. We have used electron cryotomography and three-dimensional subvolume averaging to capture snapshots of ɛ15 infecting its host Salmonella anatum. These structures suggest the following stages of infection. In the first stage, the tailspikes of ɛ15 attach to the surface of the host cell. Next, ɛ15's tail hub attaches to a putative cell receptor and establishes a tunnel through which the injection core proteins behind the portal exit the virion. A tube spanning the periplasmic space is formed for viral DNA passage, presumably from the rearrangement of core proteins or from cellular components. This tube would direct the DNA into the cytoplasm and protect it from periplasmic nucleases. Once the DNA has been injected into the cell, the tube and portal seals, and the empty bacteriophage remains at the cell surface.

Application of Automatic Mercury Injection Apparatus in Study of Astragalus Slices Drying

The objective of this article is to study the influence of pore size and distribution in plant tissue on drying behavior of plant materials using Astragalus slices as an example. By using an automatic mercury injection apparatus, the study compares the pore size distribution inside the matrix of sample dried by 200 W microwave power and hot air at 60°C. The study also characterizes the matrix microstructure by scanning electronic microscopy (SEM) and discusses the drying kinetics of the sample as well as the rehydration properties of the dried sample. Results show the advantage of automatic mercury injection apparatus over SEM to characterize the matrix microstructure of sample. This work may be helpful for further investigation on the optimization of drying process focused on micromechanisms and the quality of dried product.

Potassium-activated GTPase Reaction in the G Protein-coupled Ferrous Iron Transporter B

FeoB is a prokaryotic membrane protein responsible for the import of ferrous iron (Fe(2+)). A defining feature of FeoB is that it includes an N-terminal 30-kDa soluble domain with GTPase activity, which is required for iron transport. However, the low intrinsic GTP hydrolysis rate of this domain appears to be too slow for FeoB either to function as a channel or to possess an active Fe(2+) membrane transport mechanism. Here, we present crystal structures of the soluble domain of FeoB from Streptococcus thermophilus in complex with GDP and with the GTP analogue derivative 2'-(or -3')-O-(N-methylanthraniloyl)-beta,gamma-imidoguanosine 5'-triphosphate (mant-GMPPNP). Unlike recent structures of the G protein domain, the mant-GMPPNP-bound structure shows clearly resolved, active conformations of the critical Switch motifs. Importantly, biochemical analyses demonstrate that the GTPase activity of FeoB is activated by K(+), which leads to a 20-fold acceleration in its hydrolysis rate. Analysis of the structure identified a conserved asparagine residue likely to be involved in K(+) coordination, and mutation of this residue abolished K(+)-dependent activation. We suggest that this, together with a second asparagine residue that we show is critical for the structure of the Switch I loop, allows the prediction of K(+)-dependent activation in G proteins. In addition, the accelerated hydrolysis rate opens up the possibility that FeoB might indeed function as an active transporter.

Application of Pore Size Analyzers in Study of Chinese Angelica Slices Drying

The objective of this article is to study the influence of pore size and distribution in plant tissue on drying behavior of plant materials using Chinese Angelica slices as an example. By using an automatic mercury injection apparatus and automatic surface area–porosity analyzer, the study compares the pore size distribution inside the matrix of a sample dried by 200 W microwave and 60°C hot air. The study also characterizes the matrix microstructure by scanning electronic microscopy (SEM) and discusses the drying dynamics of the sample, as well as the rehydration property of the dried sample. This work may be helpful for further investigation of the optimization of drying technology focused on micromechanisms and the quality of dried products.

Rapid sample injection for hyperpolarized NMR spectroscopy

Due to its ability to enhance the signal of a single NMR scan by several orders of magnitude, solid-to-liquid state dynamic nuclear polarization (DNP) appears well suited for the analysis of minimal amounts of compounds, as well as for the study of rapid chemical reactions. A key requirement in enabling the application of DNP-NMR to typical small-molecule substances encountered in chemistry and biochemistry is the ability to obtain high-resolution spectra, while at the same time minimizing the loss of polarization due to spin relaxation between the separate steps of DNP polarization and NMR measurement. Here, we present data demonstrating the capability of measuring DNP enhanced NMR spectra of compounds with comparably short relaxation times, with only minimal line broadening attributable to the sample transfer process. We discuss the performance characteristics of a sample injection apparatus specifically designed to provide high-resolution DNP-NMR spectra of small molecule compounds.

The measurement of compositions and the isotopic distribution of released fission gas in the fuel rods of pressurized water reactors (PWR) of Korea

In this work the analysis procedures of fission gas compositions and their isotopic distributions using a gas chromatography (GC) system and/or a quadrupole mass spectrometer (QMS) system were established, and their analysis results were reviewed in order to evaluate their analytical performance. Also, the accumulated data, up to now, regarding fission gas measurement were reviewed to discern any irradiation histories of the punctured fuel rods. A simple gas injection apparatus was designed and fabricated for the quantitative injection of a small volume of fission gas into the GC and the QMS system. With an appropriate temperature controlling of a molecular sieve 5A column, nitrogen, krypton and xenon of a mixture gas was clearly separated within 7 min. According to the analysis results, the relative standard deviation in the determination of fission gas compositions, krypton and xenon, by the GC analysis or by the QMS analysis was about 1%. Based on the review results of the isotopic ratios of krypton and xenon of the released fission gas, it is likely that no abnormally irradiated rods, i.e. defected rods, were included among the punctured rods.

Experimental investigation on granite emplacement during shortening

We present analogue experiments performed to investigate the emplacement of granitic plutons in a shortening upper crust. The models were made of quartz–sand to simulate the brittle crust and a low-viscosity mixture of silicone and oleic acid to reproduce granitic magmas. Shortening of the models was obtained by a moving wall while a special injection apparatus allowed syn-kinematic magma intrusion from the base of the models. Experimental results show that: (1) space for intrusions is achieved during the movement along thrust faults and mostly coincides with low-pressure areas developed into the thrust–anticlines; (2) intrusion shapes are strictly dependent upon the competition between shortening rate (Sh) and injection rate (Inj). For high Sh/Inj values, plutons were elongated with the long axis parallel to the thrust surfaces; (3) magma migrates horizontally away from the injection point and towards the external sector in the direction of tectonic transport a longer distance for high Sh/Inj values; (4) syn-kinematic emplacement is also controlled by model thickness; an increase in this parameter results in an increase in the pluton plan-view aspect ratio. These results support that the final shape of orogenic plutons emplaced at shallow crustal levels may be strongly controlled by deformational features.

Mechanical Property and Crystal Structure of Nylon6 Samples Prepared by Vibration Injection Molding

An injection apparatus with a pressure vibration field was self-developed to study the effects of vibration frequency and vibration pressure on the mechanical properties and crystal structure of nylon6 during the process of vibration injection molding. Scanning electron microscope (SEM) and wide-angle X-ray diffraction (WAXD) measurements were conducted. Experimental results showed that the amount of spherulites in subsurface of vibration sample is much more than that of static sample, and the spherulites become more uniformly and perfect. In subsurface layer, vibration induced the change of crystal form from γ-form to α-form. Tensile and impact strength of samples obtained via vibration injection molding were improved, while the elongation decreased.

病原細菌の分泌装置：その機能と病原性発揮のメカニズム

Bacterial pathogens possesses certain secretion systems to maintain their homeostasis and to exert full virulence. Currently, two translocons including Sec and Tat, and 7 secretion systems are found in Gram-positive and -negative bacteria. Some virulence factors, which are referred to as effectors, are directly translocated into the host cell via an injection apparatus, i.e., the type III secretion system. Thus, characterization of secretion systems and their delivered proteins into extracellular milieus is required for understanding of strategies of bacterial pathogens.

Flow Injection Analysis of Iodate Reduction on PEDOT Modified Electrode

AbstractPoly‐(3,4‐ethylenedioxythiophene) (PEDOT) films were electrodeposited by cyclic voltammetry on glassy carbon electrode at different anodic potentials in the range of 1.0–1.5 V (Ag/AgCl) and its electrocatalytic properties towards reduction of iodate were reported. The effect of the pH of the solution on the response of PEDOT electrode towards iodate also studied. The modified electrode was employed successfully as an amperometric sensor for iodate in a flow injection apparatus. The repeatability of the method for 14 injections of a μM iodate solution was 7%. Interference from other oxidant anions such as nitrate was not noticeable, whereas bromate, chlorate and nitrite interfere at slight levels.

Dopamine Detection with Fast-Scan Cyclic Voltammetry Used with Analog Background Subtraction

Fast-scan cyclic voltammetry has been used in a variety of applications and has been shown to be especially useful to monitor chemical fluctuations of neurotransmitters such as dopamine within the mammalian brain. A major limitation of this procedure, however, is the large amplitude of the background current relative to the currents for the solution species of interest. Furthermore, the background tends to drift, and this drift limits the use of digital background subtraction techniques to intervals less than 90 s before distortion of dopamine signals occurs. To minimize the impact of the background, a procedure termed analog background subtraction is reported here. The background is recorded, and its inverse is played back to the current transducer during data acquisition so that it cancels the background in subsequent scans. Background drift still occurs and is recorded, but its magnitude is small compared to the original background. This approach has two advantages. First it allows the use of higher gains in the current transducer, minimizing quantization noise. Second, because the background amplitude is greatly reduced, principal component regression could be used to separate the contributions from drift, dopamine, and pH when appropriate calibrations were performed. We demonstrate the use of this approach with several applications. First, transient dopamine fluctuations were monitored for 15 min in a flowing injection apparatus. Second, evoked release of dopamine was monitored for a similar period in the brain of an anesthetized rat. Third, dopamine was monitored in the brain of freely moving rats over a 30 min interval. By analyzing the fluctuations in each resolved component, we were able to show that cocaine causes significant fluctuations in dopamine concentration in the brain while those for the background and pH remain unchanged from their predrug value.

Experimental Investigation of the Stability Mechanism and Emissions of a Lifted Swirl Nonpremixed Flame

We report on the experimental investigation of a confined lifted swirl nonpremixed flame by applying a novel Airblast nozzle (Zarzalis, N., et al., 2005, Fuel Injection Apparatus, Patent No. DE 10 2005 022 772.4, EP 06 009 563.5). 3D-laser doppler anemometry, a nonintrusive, laser-based measurement technique, is adapted for the measurement of all three mean velocity components and of the six Reynolds stress components. The determination of the temperature and mixture field occurs by employing in-flame measurement techniques. Valuable information concerning the mixing procedure, the temperature distribution, the turbulence level, and the velocity field of the flame is provided. The results demonstrate that there is sufficient residence time in the precombustion area of the lifted flame in order to achieve spatial and temporal uniformity of the mixture, leading to a quasi-premixed state. It was also found that hot reaction products, carried upstream by an annular zone of reverse flow, react with fresh unburnt mixture in a re-ignition process. The determination of the flow pattern revealed the presence of an inner weak recirculation zone in the nozzle vicinity and a dominant external recirculation zone. The examination of the probability density function of the velocity measurements was also found to be a very useful tool in terms of the analysis of the turbulence structure of the flow. The bimodal distribution in the shear layer between the downstream flow and the recirculated gases yields the existence of large scale eddies. Finally, the significant reduced NOx emissions in the lean area were also shown by means of emission measurements for elevated pressure conditions.

Flow injection analysis of blood l-lactate by using a Prussian Blue-based biosensor as amperometric detector

An amperometric l-lactate biosensor was fabricated by confining lactate oxidase in a Prussian Blue-modified electrode with a Nafion membrane. The detector was assembled in a flow injection apparatus and operated at −0.1 V. Conditions for optimal electrode response were determined by investigating the influence of the amount of immobilized enzyme, the sample volume, and the flow rate. At the established operational conditions, the biosensor exhibited negligible response from interfering species usually present in biological fluids. The stability of the biosensor was also investigated, and its sensitivity was maintained unchanged at certain experimental conditions. l-Lactate was determined in blood samples, and the influence of physical exercise on the results was clearly evidenced, demonstrating that the proposed amperometric detector is suitable for monitoring changes in the l-lactate levels in biological fluids.

Determination of Nitric Oxide by Quenching Electro‐Chemiluminescence of Tris(2,2′‐Bipyridyl)ruthenium in Flow Injection Analysis

AbstractQuenching of the electro‐chemiluminescence of the ruthenium complex was applied for detection of NO at the flow injection apparatus equipped with a homemade gas pressure pump with low noise and a flow‐through electrogenerated chemiluminescence (ECL) cell. NO quenched the ECL emission of Ru(bpy)32+ at the potential of the oxidation of Ru(bpy)32+ efficiently to set the detection limit of NO at 0.1% of concentration of Ru(bpy)32+. The decrease in ECL intensity is linearly dependent on the logarithmic concentration of NO in the range of 5.7×10−7 M to 1.8×10−5 M. Voltammetric and spectrometric analysis showed that NO was not coordinated to Ru(bpy)32+/3+, but catalyzed the quenching reaction.