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Resting‐state functional connectivity (RSFC) records enormous functional interaction information between any pair of brain nodes, which enriches the individual‐phenotypic prediction. To reduce high‐dimensional features, correlation analysis is a common way for feature selection. However, resting state fMRI signal exhibits typically low signal‐to‐noise ratio and the correlation analysis is sensitive to outliers and data distribution, which may bring unstable features to prediction. To alleviate this problem, a bootstrapping‐based feature selection framework was proposed and applied to connectome‐based predictive modeling, support vector regression, least absolute shrinkage and selection operator, and Ridge regression to predict a series of cognitive traits based on Human Connectome Project data. To systematically investigate the influences of different parameter settings on the bootstrapping‐based framework, 216 parameter combinations were evaluated and the best performance among them was identified as the final prediction result for each cognitive trait. By using the bootstrapping methods, the best prediction performances outperformed the baseline method in all four prediction models. Furthermore, the proposed framework could effectively reduce the feature dimension by retaining the more stable features. The results demonstrate that the proposed framework is an easy‐to‐use and effective method to improve RSFC prediction of cognitive traits and is highly recommended in future RSFC‐prediction studies. [ABSTRACT FROM AUTHOR]

In order to reduce the harmful emissions from marine diesel engines, the use of alternative fuels is a promising option. In this study, the combustion process and NOx emissions and composition ratios of waste cooking oil biodiesel on a marine auxiliary diesel engine were investigated experimentally. Four different blended ratios of biodiesel and diesel were selected. The results showed that the peak of heat release rate (PHRR) decreased with the increasing biodiesel blended ratios at most of the operation conditions. The maximum reductions of PHRR were 11.04% and 19.86% at speeds of 1050 rpm and 1500 rpm. The brake specific fuel consumption (BSFC) increased but the brake thermal efficiency (BTE) changed little when the biodiesel blended ratio increased. The maximum increments of BSFC were reached at B50 and were 7.0%–8.3% and 5.1%–6.1% at 1050 rpm and 1500 rpm under different engine loads. With the increase of biodiesel blended ratios, NOx emissions decreased and NO 2 /NOx increased slowly due to the decline of in-cylinder temperature. While NO 2 /NOx decreased significantly with the increasing engine speed and load for the reduction of in-cylinder cooler regions. In general, the waste cooking oil biodiesel can be considered as an alternative fuel for marine auxiliary diesel engines. [ABSTRACT FROM AUTHOR]

• Internal feature of biodiesel jet can be captured by fast X-ray phase-contrast imaging. • Feature detection and matching were used to analyze the near-field jet stability. • Five stages of biodiesel jet stability were found for a single-hole injector. • Near-field jet feature was highly dependent on the needle lift. Fuel spray is very effective in controlling the combustion process to improve engine performance and reduce emissions. Understanding the spray unstability during the injection process is of importance to improve the control of spray characteristics and engine operation. In this study, near-field biodiesel jets were recorded using fast X-ray phase contrast imaging and the flow features inside the jet were extracted using Speeded Up Robust Features (SURF) method. The image similarity by feature matching was successfully used to represent the near-field jet stability. Based on the jet stability, an injection process can be divided into five stages: an unstable stage at needle opening, a partially stable transition stage at needle opening, a stable stage, a stable transition stage at needle closing and an unstable stage at needle closing. The ranges of needle lift for five stages were also determined. The jet unstability is highly related to the cavitation formation and gas purging process during needle opening. The variation of stable jet feature is dependent on the needle lift at needle closing. Higher needle lift for the similar jet feature at needle opening indicates a hydraulic delay compared to needle closing. Finally, the possible reasons of jet feature formation and feature detection used on the multi-hole injector are discussed. [ABSTRACT FROM AUTHOR]

With the increasing concern regarding diesel engine emissions, including nitrogen oxides (NO X ) and particulate matter (PM), and the rising of energy demand as well, the utilization of alternative fuels in diesel engine has been found to be an attractive solution. Natural gas is a very promising and highly attractive fuel because of its domestic availability, widespread distribution infrastructure, low cost, and clean-burning qualities to be used as a transportation fuel. Natural gas/diesel dual fuel is an operation mode in which natural gas is introduced into the intake air upstream of the manifold and then ignited by the direct injected diesel in the cylinder. The aim of this paper is to identify the potential use of natural gas/diesel dual fuel on diesel engine. In this literature review, the combustion, emission and performance characteristics of natural gas/diesel dual fuel combustion-mode published mainly in scientific journals have been collected and critically analyzed. A wide range of natural gas mass ratio which represents the mass fraction of natural gas in the total fuel and different types of engines were involved. It has been found that dual fuel mode has a lower compression pressure and a longer ignition delay compared with normal diesel mode. The application of dual fuel mode significantly decreases the NO X , carbon dioxide (CO 2 ) and PM emissions. However, the hydrocarbon (HC) and carbon monoxide (CO) emissions may increase by several times or even more than 100 times in comparison to normal diesel combustion. And there appears a trade-off relationship between NO X and HC emissions with dual fuel mode. The engine power is decreased up to 2.1% at dual fuel mode, but the power loss can be reduced or recovered by changing some of the operating parameters. The brake thermal efficiency (BTE) of dual fuel mode is lower at low and intermediate loads, while under high engine load conditions it is similar or a little higher when compared with normal diesel mode, and the maximum increase is about 3%. The COV IMEP seems to be generally higher than normal diesel mode and it decreases with the increasing engine load. [ABSTRACT FROM AUTHOR]

In this study, port premixed methanol compression ignition combustion was performed on a heavy-duty diesel engine. The effects of methanol to diesel ratio (R MD ) and DIT (diesel injection timing) on combustion, performance and emissions were comprehensively investigated. The experimental results demonstrated that R MD and DIT played important roles in combustion and emission control. With the increasing R MD , the ignition delay was prolonged and the combustion duration was shortened. And as DIT retarded, the ignition delay was also prolonged and the combustion duration basically remained unchanged at the beginning, and then followed by a slight decrease. The maximum in-cylinder mean temperature decreased with the retarding DIT and it was largely affected by the combine of R MD and DIT. The brake thermal efficiency remained stable at low R MD , but showed a slight decrease at high R MD. NO X and soot emissions and the RI (ringing intensity) were all decreased as RMD increase, while HC and CO emissions increased significantly. With the retarding DIT, HC emission firstly increased and then decreased, while CO emission always increased. It was more important that the trade-off relationship between NO X and soot was significantly improved with the increasing R MD and almost disappeared at R MD 1.54. [ABSTRACT FROM AUTHOR]

The combustion and emission characteristics of a dual fuel diesel engine with high premixed ratio of methanol (PR m ) were investigated. Experiments were performed on a 6-cylinder turbocharged, inter-cooling diesel engine. Methanol was injected through the intake port and ignited by direct injected diesel in the cylinder, the maximum PR m was over 70%. The experimental results showed that with high PR m , the maximum in-cylinder pressure increased from medium to high engine load but varied little or even decreased at low engine speed and load. High PR m prolonged the ignition delay but shortened the combustion duration and decreased the in-cylinder gas temperature at ignition timing. Hydrocarbons (HC), carbon monoxide (CO), formaldehyde emissions and the proportion of nitrogen dioxide (NO 2 ) in nitrogen oxides (NO X ) increased significantly with the increase of PR m while NO X and dry soot emissions were significantly reduced, which meant the trade-off relationship between NO X and soot emissions disappeared. The increased HC, CO and formaldehyde emissions could be effectively reduced by diesel oxidation catalyst (DOC) when the exhaust gas temperature reached the light off temperature of the DOC. After DOC, the NO 2 proportion in NO X was greatly reduced to less than that of baseline engine at methanol premixed mode but increased slightly at pure diesel mode. The maximum PR m was confined by in-cylinder pressure at high engine speed and load. But at low engine speed and load, it was confined by the high emissions of HC, CO and formaldehyde even after DOC. [ABSTRACT FROM AUTHOR]

An experimental study was conducted to investigate the operating range and combustion characteristics in a methanol fumigated diesel engine. The test engine was a six-cylinder, turbocharged direct injection engine with methanol injected into the intake manifold of each cylinder. The experimental results showed that the viable diesel methanol dual fuel (DMDF) operating range in terms of load and methanol substitution percent (MSP) was achieved over a load range from 6% to 100%. The operating range was restricted by four bounds: partial burning, misfire, roar combustion and knock. The lower bound of the operating range was the partial burn bound, which occurred under very low load conditions with high MSP. As the load increased to medium load, MSP reached its maximum value of about 76%, and the onset of misfire provided the right bound for normal operation. At medium to high load, maximum MSP began to decrease. DMDF combustion with excessive MSP was extremely loud with high pressure rise rate, which defined the roar combustion bound. As it increased to nearly full load, measured pressure traces in-cylinder showed strong acoustic oscillations. The appearance of knock provided the upper bound of the operating range. In general, as the load increased, the characters of the combustion changed from partial burn to misfire to roar combustion and to knocking. The range between these four bounds and the neat diesel combustion bound constituted the viable operating range. Over the viable operating range, DMDF combustion worsened the brake thermal efficiency (BTE) at light load while boosted it at medium and high load. [ABSTRACT FROM AUTHOR]

In this paper, an integrated fault-tolerant control (FTC) strategy is proposed for unmanned helicopter system under aggressive maneuvers. In order to handle the effect of strong nonlinearities caused by large pitch angle, linear parameter varying (LPV) technique is adopted in the helicopter system modeling. Then, LPV model-based unknown input observer (UIO) design is conducted to simultaneously realize actuator faults and system state estimation, based on which an active fault-tolerant controlleris also constructed. Considering bi-directional robustness interactions between fault as well as state observer and active fault-tolerant controller, an integrated fault-tolerant controller design is further developed. Besides, actuator saturation is also considered in LPV modeling as well as integrated fault-tolerant controller design of the helicopter system. In order to guarantee the robust performance of proposed integrated fault tolerant controller design of helicopter system, energy-to-energy strategy is adopted. And the linear matrix inequality (LMI) toolbox is utilized for gain calculation. Finally, comparative experimental tests are carried out to show the effectiveness and advantages of the proposed FTC strategy. [ABSTRACT FROM AUTHOR]

Background: We investigated the role of ANGPTL3 and ANGPTL4 in atherosclerosis development and determined whether plasma concentrations of ANGPTL3 and ANGPTL4 are related to the degree of coronary stenosis. Methods: A total of 305 consecutive patients with angina who underwent diagnostic coronary angiography were enrolled in the study between August 2017 and August 2018. The levels of ANGPTL3 and ANGPTL4 were measured by using competitive ELISA kits. Results: According to the degree of coronary artery stenosis, patients were classified into four types: coronary artery stenosis of < 10%, 10-50%, 50-75, and > 75%. The plasma ANGPTL3 level was higher (51.71 ± 52.67 vs. 24.65 ± 10.32 ng/mL, P < 0.001) and that of ANGPTL4 was lower (454.66 ± 269.05 vs. 875.49 ± 961.15 ng/mL, P < 0.001) in the coronary artery stenosis ≥ 10% group than in the < 10% group. ANGPTL3 and ANGPTL4 levels were significantly associated with the severity of coronary vascular stenosis. ROC curve analyses indicated that ANGPTL3 concentrations above 30.5 ng/mL can predict atherosclerosis with a sensitivity of 71.2% and specificity of 75.3%, and that ANGPTL4 levels below 497.5 ng/mL can predict atherosclerosis with a sensitivity of 63.9% and specificity of 74.5%. ANGPTL3 and ANGPTL4 were determined to be independent risk factors for coronary atherosclerosis with odds ratios (ORs) of 0.189 (95% CI 0.097-0.368, P < 0.001) and 3.625 (95% CI 1.873-7.016, P < 0.001), respectively. Conclusions: Increased ANGPTL3 or decreased ANGPTL4 shows an association with coronary atherosclerosis and, may become a predictor of coronary atherosclerosis in the future. [ABSTRACT FROM AUTHOR]

Abnormal proliferation of pulmonary arterial smooth muscle cells (PASMCs) is a key mechanism in the development of pulmonary arterial hypertension (PAH). Signal transducer and activator of transcription 3 (STAT3) signalling plays a critical role in modulating PASMC proliferation, and G-protein-coupled receptor kinase 6 (GRK6) regulates the STAT3 pathway. However, the mechanism underlying the relationship between GRK6 and PAH remains unclear. In this study, we aimed to investigate the role of GRK6 in PAH and determine its potential as a therapeutic target. We utilised hypoxia- and SU5416-induced PAH mouse models and a monocrotaline-induced PAH rat model to analyse the involvement of GRK6. We conducted gain- and loss-of-function experiments using mouse PASMCs. Modulation of GRK6 expression was achieved via a lentiviral vector in vitro and an adeno-associated virus serotype 1 encoding GRK6 in vivo. GRK6 was significantly downregulated in the lung tissues of PAH mice and rats, predominantly in PASMCs. Knockout of GRK6 exacerbated PAH, while both therapeutic and prophylactic overexpression of GRK6 alleviated PAH, as evidenced by a reduction in right ventricular systolic pressure, right ventricular wall to left ventricular wall plus ventricular septum ratio, pulmonary vascular media thickness, and pulmonary vascular muscularisation. Mechanistically, GRK6 overexpression attenuated hypoxia-induced PASMC proliferation and STAT3 phosphorylation. Conversely, knockdown of GRK6 promoted hypoxia-induced proliferation, which was mitigated by a STAT3 inhibitor. Our findings highlight the potential protective and beneficial roles of GRK6 in PAH; we propose a lung-targeted GRK6 gene therapy utilizing adeno-associated virus serotype 1 as a potential treatment approach for patients with PAH. Deficiency of GRK6 enhances hypoxia-induced proliferation of pulmonary arterial smooth muscle cells by increasing the activity of p-STAT3 in PAH. AAV.GRK6 attenuated hypoxia-induced PAH by inhibiting STAT3 activation and PASMC proliferation. [Display omitted] • Knockout of GRK6 exacerbated PAH. • Therapeutic and prophylactic overexpression of GRK6 alleviated PAH. • GRK6 overexpression reduced hypoxia-induced PASMC proliferation and STAT3 phosphorylation. • GRK6 overexpression-induced changes ameliorated vascular remodelling in PAH. • GRK6 could serve as a potential target for the prevention and alleviation of PAH. [ABSTRACT FROM AUTHOR]

• The average dwell time of activity in DMN is shortened in AD. • The system entropy of the brain state-space increases in AD. • The alteration of temporal organization may associate with CSF biomarkers. The alterations of dynamic brain functions in Alzheimer's disease (AD) remain far from well understood. In this study, using functional magnetic resonance imaging (fMRI) data, we adopted a co-activation pattern (CAP) approach, which relies on very few assumptions, to explore the differences of brain dynamics among healthy elderly, patients with early amnestic mild cognitive impairment (MCI) and patients with AD. Briefly, k-means clustering was applied to all fMRI frames from the three groups and generated a set of reproducible CAPs. We found the obtained CAPs showed high correspondence to the well acknowledged functional networks including default mode network (DMN), executive control network and visual networks, etc. Different from previous CAP-based studies, we further quantitatively analyzed the temporal dependence of the CAPs using multiple parameters. Primary findings include, for AD and MCI compared with NC, the decreased mean fraction of occurrence and persistence of DMN related CAPs, which indicates the typical DMN damage; the increased/decreased mean persistence of ventral/dorsal visual network related CAPs, which may associate with the visuospatial disorder of patients with AD pathology; the elevated transition and CAP entropies and multiple alterations of CAP transition probabilities, which imply the altered mode of information flow and lifted system uncertainty in AD brains. We also found correlations of proposed measurements to cerebrospinal fluid biomarkers and neuropsychological scores. This study verified the AD-related alteration found by traditional FC analysis, and proposed several new biomarkers which have the potential for assisting AD treatment and early diagnosis. [ABSTRACT FROM AUTHOR]

Complex robotic systems often have to operate in large environments. At the same time, their dynamic is complex enough that path planning algorithms need to reason about the differential constraints of these systems. On the other hand, such robotic systems are typically expected to operate with speed that is commensurate with that of humans. This poses stringent limitation on available planning time. A common approach is to use a two-dimensional(2-D) global planner for long range planning, and a short range higher dimensional planner or controller capable of satisfying all of the constraints on motion. However, this approach is incomplete and can result in oscillations or even the inability to find a path to the goal. In this paper, we present an approach to solve this problem by combining the global and local path planning problem into a single search scheme using a combined 2-D and higher dimensional state space. The proposed approach is demonstrated and validated in simulation and experiment with a significantly asymmetric differential drive robot. [ABSTRACT FROM AUTHOR]

In order to meet the stringent Diesel-engine emission regulations, an aftertreatment system has become more and more popular in many countries. Specifically, to reduce the NO x emissions, a selective catalytic reduction (SCR) system has been successfully applied to many Diesel-engine applications. In the SCR system, NO x sensors are used to monitor the NO x concentration for the control strategies design and fault diagnosis. However, studies show that current NO x sensors are often cross-sensitive to ammonia. Thus, the reading of NO x sensor located at downstream of the SCR catalyst may not be accurate, due to the existing of ammonia slip in the system. Aiming to address this problem, some observers based on Kalman filtering theory are utilized to estimate the cross-sensitivity factor and the actual NO x concentration. Inspired by the fact that the adaptive unscented Kalman filter (AUKF) has the advantages of sample calculation and the capacity to deal with nonlinear system, the AUKF-based observer is investigated to estimate the factor in this paper. In addition, the process noise and measurement noise are usually unknown and time-varying in actual conditions. The AUKF would be effective to update the process and measurement noise covariance matrices online to adapt the practical SCR system. Simulation results through an experimentally-validated full vehicle simulator cX-Emission prove that the performance of designed observer based on AUKF is excellent. [ABSTRACT FROM AUTHOR]

Highlights: [•] PM and dry-soot from turbo-charged diesel engine with DMDF were measured. [•] Relation on dry-soot emission and PM was analyzed. [•] Effects of DMDF, DOC and intake air temperature on PM and dry-soot were investigated. [•] Particle number and mass concentration on different loads with DMDF were realized. [ABSTRACT FROM AUTHOR]

Mild cognitive impairment (MCI) exhibits a high risk of progression to Alzheimer's disease (AD), and it is commonly deemed as the precursor of AD. It is important to find effective and robust ways for the early diagnosis of MCI. In this paper, a random forest-based method combining multiple morphological metrics was proposed to identify MCI from normal controls (NC). Voxel-based morphometry, deformation-based morphometry, and surface-based morphometry were utilized to extract morphological metrics such as gray matter volume, Jacobian determinant value, cortical thickness, gyrification index, sulcus depth, and fractal dimension. An initial discovery dataset (56 MCI/55 NC) from the ADNI were used to construct classification models and the performances were testified with 10-fold cross validation. To test the generalization of the proposed method, two extra validation datasets including longitudinal ADNI data (30 MCI/16 NC) and collected data from Xuanwu Hospital (27 MCI/32 NC) were employed respectively to evaluate the performance. No matter whether testing was done on the discovery dataset or the extra validation datasets, the accuracies were about 80% with the combined morphological metrics, which were significantly superior to single metric (accuracy: 45% ∼76%) and also displayed good generalization across datasets. Additionally, gyrification index and cortical thickness derived from surface-based morphometry outperformed other features in MCI identification, suggesting they were some key morphological biomarkers for early MCI diagnosis. Combining the multiple morphological metrics together resulted in a significantly better and reliable identification model, which may be helpful to assist in the clinical diagnosis of MCI. [ABSTRACT FROM AUTHOR]

Diesel engines are the main source of rapidly-growing energy consumption worldwide. Diesel consumption is responsible for serious air pollution, which includes nitrogen oxides (NOx), hydrocarbon (HC), carbon monoxide (CO) emissions and some particulate matter (PM) discharged from the combustion chamber. In the past few decades, alternative fuels, such as alcohol, biodiesel, natural gas, and Di Methyl Ether (DME), have been used in diesel engines to reduce energy costs and environmental pollution. As a result of alternative fuels directives, an increasing number of diesel engines have adapted dual fuel blends, and an enormous amount of research is focused on new and inadequately studied combustion and emission profiles. Compared to conventional diesel fuel, the application of dual fuels would add new parameters to combustion and emission profiles for diesel vehicles worldwide. This review aims to reveal (1) Known and anticipated combustion characteristics and emissions products from dual fuels. (2) Toxic properties and the expected influence on engine performance. (3) Identifying promising alternative fuels for emissions control in compression combustion engines. The results presented herein will show a significant reduction of regular gas and PM emissions by the use of alcohol/diesel dual fuel, while unregulated emissions such as methanol, ethanol, acetaldehyde, formaldehyde, ketone, have increased compared to those from diesel fuel. PM emissions decreased significantly with the increase of alternative fuels, such as alcohols, natural gas, biodiesel and DME, while regular gaseous emissions varied depending on the type alternative fuel and the engine conditions. As one new and cleaner substitute for diesel engines, DME operation has a longer injection delay, lower maximum cylinder pressure, a lower ratio of pressure rise, and shorter ignition delay in comparison with diesel operation--the opposite of alcohol/diesel and dual fuels. This review evaluates the effects of some alternative fuels (alcohol, biodiesel, natural gas and Di Methyl Ether (DME)) on combustion characteristics and emission products from diesel engines to meet future emission regulations using alternative fuel. [ABSTRACT FROM AUTHOR]

In recent years, marine auxiliary diesel engine has been widely used to produce electricity in the large ocean-going ship. One of the main technical challenges for ocean-going ship is to reduce pollutant emissions from marine auxiliary diesel engine and to meet the criteria of disposal on ships pollutants of IMO (International Maritime Organization). Different technical changes have been introduced in marine auxiliary diesel engine to apply clean fuels to reduce pollutant emissions. The ultralow sulfur light fuel will be applied in diesel engine for emission reductions in China. This study is aimed to investigate the impact of fuel (ultralow sulfur light fuel) on the combustion characteristic, NOx and green house gas emissions in a marine auxiliary diesel engine, under the 50%–90% engine speeds and the 25%–100% engine torques. The experimental results show that, in the marine auxiliary diesel engine, the cylinder pressure and peak heat release rate increase slightly with the increase of engine torques, while the ignition advances and combustion duration become longer. With the increases of the engine speed and torque, the fuel consumption decreases significantly, while the temperature of the exhaust manifold increases. The NOx emissions increase significantly with the increases of the engine speed and torque. The NO emission increases with the increases of the engine speed and torque, while the NO 2 emission decreases. Meanwhile, the ratio of NO 2 and NO is about 1:1 when the diesel engine operated in the low speed and load, while the ratio increases significantly with the increases of engine speed and torque, due to the increase of the cylinder temperature in the diffusive combustion mode. Moreover, the CO 2 emission increases with the increases of engine speed and torque by the use of ultralow sulfur light fuel. [ABSTRACT FROM AUTHOR]

Diabetic nephropathy (DN) is one of the most common complications of diabetes mellitus (DM). However, the exact mechanism is not clearly understood. In this study, our results showed that 24 h urinary protein, kidney index, and glomerular area were decreased, while creatinine clearance ratio was increased in DN rats when the rats were treated with NAR 50 mg/d for 6 weeks. Mesangial cell (MMCs) proliferation was inhibited in the NAR group by 3,(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), and the cell cycle analysis showed that cells stayed in G2 phase in NAR group. And NAR treatment attenuated the deposition of ECM in DN rats and MMCs. Moreover, our data showed that let-7a was downexpressed in both DN rats and MMCs under high glucose condition. Surprisingly, NAR affected the expressions of Col4 and FN through upregulating let-7a in MMCs. In addition, we found that let-7a negatively regulated the expression of transforming growth factor-β1 receptor 1 (TGFBR1), and TGFBR1 was required for the let-7a-mediated downregulation of TGF-β1/smad signaling. Interestingly, NAR inhibited TGF-β1/smads signaling activation by upregulating let-7a. Therefore, our findings indicated that NAR ameliorated kidney injury by regulating let-7a/TGFBR1 signaling. [ABSTRACT FROM AUTHOR]

A number of measurements have been provided to detect formaldehyde in the atmosphere, but there are no clear unified standards in engine exhaust. Nowadays, formaldehyde, an unregulated emission from methanol engine, has been attracting increasing attention by researchers. This paper presents the detection techniques for formaldehyde emitted from the engines applied in recent market, introducing the approaches in terms of unregulated emission tests of formaldehyde, which involved gas chromatography, liquid chromatography, chromatography-mass spectrometry, chromatography-spectrum, Fourier infrared spectroscopy and spectrophotometry. The author also introduces the comparison regarding to the advantages of the existing detection techniques based on the principle, to compare with engine exhaust sampling method, the treatment in advance of detection, obtaining approaches accessing to the qualitative and quantitative analysis of chromatograms or spectra. The accuratest result obtained was chromatography though it cannot be used continuously. It also can be utilized to develop high requirements of emissions and other regulations. Fourier infrared spectroscopy has the advantage of continuous detection for a variety of unregulated emissions and can be applied to the bench in variable condition. However, its accuracy is not as good as chromatography. As the conclusion, a detection technique is chosen based on different requirements. [ABSTRACT FROM AUTHOR]

This study is aimed to investigate the combined application of diesel methanol dual fuel (DMDF) and a simple after-treatment for reducing particulate matter (PM) emissions of a diesel engine. The effects of DMDF, a double diesel oxidation catalyst (DDOC) and a DOC closely coupled with a particulate oxidation catalyst (POC) in series (DPOC) on smoke emissions, particulate mass and number concentrations and size distributions were analyzed. Tests were conducted on a 4-cylinder turbo-charged, inter-cooling, mechanical in-line fuel injection pump diesel engine modified to DMDF combustion mode. Testing results showed that, before the DDOC and the DPOC, the dry-soot and smoke opacity efficiency decreases with the increase of substitution ratio of methanol at high engine load. There is a significant decrease of smoke opacity in DMDF mode after the DDOC, while the DPOC has a significant effect on the reduction in dry-soot emission. There is an average reduction in dry-soot by 25% in pure diesel fuel mode after the DDOC, while in DMDF mode, the average reduction is more than 60%, and the maximum reduction in dry-soot is up to 96%. There is a slightly reduction in PM emissions at low substitution ratio of methanol, while the high substitution ratio of methanol leads to more reduction in PM emissions. After the DDOC and the DPOC, particulate number and mass concentrations, especially nuclear particles, can be significantly reduced when the exhaust gas temperature is enough high. [ABSTRACT FROM AUTHOR]