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Theory of mind (ToM) deficits in people with schizophrenia have been reported and associated with impaired social interactions. Thus, ToM deficits may negatively impact social functioning and warrant consideration in treatment development. However, extant ToM measures may place excessive cognitive demands on people with schizophrenia. Therefore, the study aimed to develop a comprehensible Assessment of ToM for people with Schizophrenia (AToMS) and evaluate its psychometric properties. The AToMs was developed in 5 stages, including item formation, expert review, content validity evaluation, animation production, and cognitive interviews of 25 people with schizophrenia. The psychometric properties of the 16-item AToMS (including reliability and validity) were then tested on 59 people with schizophrenia. The newly developed animated AToMS assesses 8 ToM concepts in the cognitive and affective dimensions while placing minimal neurocognitive demands on people with schizophrenia. The AToMS presented satisfactory psychometric properties, with adequate content validity (content validity index = 0.91); mostly moderate item difficulty (item difficulty index = 0.339-0.966); good discrimination (coefficients = 0.379-0.786), internal consistency (Cronbach's α = 0.850), and reliability (intraclass correlation coefficient = 0.901 for test-retest, 0.997 for inter-rater); and satisfactory convergent and divergent validity. The AToMS is reliable and valid for evaluating ToM characteristics in people with schizophrenia. Future studies are warranted to examine the AToMS in other populations (e.g., people with affective disorders) to cross-validate and extend its utility and psychometric evidence.

Exhaust emissions from the large population of motorcycles are a major issue in Asian countries. The regulation of exhaust emissions is therefore becoming increasingly stringent, with those relating to nitrogen oxides (NOx) the most difficult to pass. The homogeneous charge compression ignition (HCCI) has special combustion characteristics and hence produces low NOx emissions and exhibits high thermal efficiency. This study developed an HCCI system for a 150 cc motorcycle engine. The target engine was modified using a dual-fuel of dimethyl ether (DME) and gasoline with exhaust gas recirculation (EGR). It was tested at 2000&ndash, 4000 rpm and the analysis was focused on 2000 rpm. The DME was supplied continuously at an injection pressure of 1.5 kg/cm2. The gasoline injection rate was adjusted at a pressure of 2.5 kg/cm2. A brake-specific fuel consumption of &lt, 250 g/kW&middot, h was achieved under a condition of air&ndash, fuel equivalence ratio (&lambda, ) &lt, 2 and an EGR of 25%. The nitric oxide concentration was too low to measure. The brake mean effective pressure (BMEP) increased by 65.8% from 2.93 to 4.86 bar when the EGR was 0% to 25%. The combustion efficiency was close to 100% when the BMEP was &gt, 3 bar.

Because Asian countries have a large number of motorcycles, motorcycle engine exhaust emission poses a major problem in the region. Homogeneous charge compression ignition (HCCI) is a promising combustion technology with high efficiency and low nitrogen oxide emission. This study investigated the combustion characteristics of HCCI in a 150 cc motorcycle engine with three types of dual fuel. The main fuels consisted of dimethyl ether (DME), kerosene, and n-heptane, and gasoline was the additive fuel. External exhaust gas recirculation (EGR) was used to expand the operating range of the engine. All test points were executed under stable HCCI operation with a coefficient of variation 0.9. The findings suggest that adjusting the CA50 to a value greater than 5° after top dead center, or limiting the maximum cylinder pressure to < 50 bar is crucial to preventing excessive pressure rising. Overall, kerosene was deemed unsuitable for engines because of its high sulfur content, whereas DME is considered an excellent option.

This paper develops an adaptive idle speed control strategy for a V2, 1000 cc four-stroke, water-cooled, port injection SI engine. In order to verify the proposed strategy, the non-dimensional engine model including charging and torque dynamics is established in Matlab/Simulink software based on previously experimental verification. The integration of dynamics above will be a multi-input-single-output (MISO) system, which inputs are throttle angle and spark advance angle, and the output is engine speed. The proposed adaptive controller is developed on the model-based structure. The system parameters are updated by recursive least square (RLS) method so the system is able to represent the actual operation. The updated system parameters adjust control gain by derivation of closed-loop gain and pole placement. This research also applies RLS method in torque load identification, and uses feedforward control module to calculate the desired throttle opening for the corresponding engine torque. The feedforward throttle control makes controller less angle of spark advance, therefore, the tracking time could be reduced. In order to verify the proposed adaptive idle speed controller performance, the conventional proportional integral derivative (PID) idle speed controller is established. The results show the proposed feedforward adaptive controller can obviously improve about 40% of tracking time with ramps load. In addition, when the water pump load is added, the proposed strategy can also improve about 20%. Finally, the results of the proposed strategy are also improved comparing to the conventional PID control as deposits happen.

Neck pain is a common cause of disability. This study investigated the psychometric properties of the cervical nonorganic signs (CNOS), a tool for assessing abnormal illness behaviors in patients with neck pain.The CNOS was administered on patients with neck pain. Reliability and validity analyses were used to evaluate the psychometric properties. Exploratory factor analysis was used to investigate the dimensionality. Correlations with the Short Form-36 were used to investigate the convergent validity.The results supported the reliability (inter-rater reliability intra-class correlation: 0.920), validity (correlated with body pain (|ρ|=0.31) and vitality (|ρ| =0.30), and two-factor dimensionality (χThe CNOS is a reliable and valid instrument for assessing pain and vitality problems. It helps patients to express severe pain and lack of vitality. The rehabilitation discipline could use the scale to understand pain expression and to design proper rehabilitation programs. Implications for Rehabilitation The cervical nonorganic signs has two domains (pain and vitality). The scale is reliable and valid for patients with neck pain. Patients with high scores on the pain domain have severe body pain that may interfere with normal social activities. Clinicians should understand their suffering and try to help them to alleviate the pain.

This paper designs a lean-burn system and its control strategies to retrofit the motorcycle engine as a semi-direct injection (SDI) engine. The lean-burn system of the SDI engine consists of a high-swirl charge, fuel injection during intake-valve opening, and liquefied petroleum gas (LPG) as the fuel. The high-swirl charge motion is generated by the new intake port with a controllable plate which is designed using the computational fluid dynamics software. The lean limit is therefore extended due to the stratified charge by higher in-cylinder swirl motion. By controlling the controllable plate, the SDI engine can be operated in stratified mode with leaner air-fuel ratio (AFR) at lower load and engine speed. The SDI engine can be switched to homogeneous mode with stoichiometric AFR for higher load and engine speed. Therefore, the proposed control strategies consist of an engine management system, adaptive intake manifold pressure control, adaptive torque control in stratified mode, adaptive torque control in homogeneous mode, and switching strategies for switching between stratified and homogeneous modes. The SDI engine and its control strategies are verified with the motorcycle test on a chassis dynamometer. The tests including driving cycle and constant speed test are executed to investigate the fuel economy of SDI engine as compared with original engine. The raw emissions of idle operation between SDI and original engines are investigated as well. Experimental results show that the SDI engine can reduce the exhaust emissions and fuel consumption as compared with original engine.

This paper describes a systematic procedure, which includes analysis of strategy design criteria and development of real-time implementable strategy, to investigate the power management strategy for a range extended electric vehicle (RE–EV) using dynamic programming (DP). Since battery life is an important factor in replacement costs, battery energy losses are treated as one design criterion for battery protection. Fuel energy losses are another design criterion to address fuel economy. These two design criteria are expressed as two different cost functions for DP to evaluate both fuel-energy-loss-oriented and battery-energy-loss-oriented power management strategies. Considering driver comfort and battery life, limitations of noise, vibration, harshness, and battery charging/discharging currents are expressed as constraints in the DP process. Analysis results show that the fuel-energy-loss-oriented strategy can have better fuel economy, but its higher battery energy losses and average charging/discharging currents are unfavorable for battery life. On the contrary, battery-energy-loss-oriented strategy sacrifices some fuel economy in exchange for benefits to battery life. A rule-based, multi-mode switch strategy is then proposed as a power management strategy for RE–EV, which can require lower computation efforts. The proposed strategy employs a driving pattern recognition technique of switching among the control rule sets extracted from DP results of each representative driving pattern. Simulation results using three untrained driving patterns show that the proposed strategy improves the control performance of fuel economy and battery protection compared to that of conventional thermostat control strategy.

The present study consisted of two phases: development and psychometric validation of a Chinese version of the Hooper Visual Organization Test (HVOT) using Rasch analysis and the provision of normative data on the basis of a representative sample of the Chinese-speaking population. The HVOT was administered to 1008 healthy adults aged 15-79 years, 60 patients with stroke, and 60 patients with schizophrenia. The results indicated that with 12 items removed, the resulting 18-item scale was found to be unidimensional, with satisfactory internal consistency and no evidence of differential item functioning or bias for age, sex and educational level. There were significant differences between each of the two patient groups and normal controls on the scores of the Rasch-developed measure. All test-retest coefficients exceeded 90 in patient samples. As performance on the Chinese version decreases with age and lower years of education, regression-based normative data that took age and education into account were established. A cut-off score of 21.5, out of an x-y range, the higher the better, resulted in a sensitivity of 0.86 and a specificity of 0.68. The normative data presented here will enable clinicians to determine different levels of visuosynthetic impairments more precisely.

The goal of this study was to examine the relationship between the validity of postural movement and bilateral motor integration in terms of sensory integration theory. Participants in this study were 61 Chinese children ages 48 to 70 months. Structural equation modeling was applied to assess the relation between measures tapping postural movement and bilateral motor integration: for postural movement, the measures involve the Monkey Task, Side-Sit Co-contraction, Prone on Elbows, Wheelbarrow Walk, Airplane, and Scooter Board Co-contraction from the DeGangi-Berk Test of Sensory Integration, and Standing Balance with Eyes Closed / Opened in Southern California Sensory Integration Tests. For bilateral motor integration, the measures chosen were the Rolling Pin Activity, Jump and Turn, Diadokokinesis, Drumming, and Upper Extremity Control from the DeGangi-Berk Test of Sensory Integration, and Cross the Midline in Southern California Sensory Integration Tests (SCSIT). Postural movement was highly correlated with the bilateral motor integration. The factor structure fit the theoretical conceptualization, classifying postural movement and bilateral motor integration together in the same category. Therapists could combine two separate objectives (postural movement and bilateral motor integration) of intervention in an activity to improve the adaptive skills based on the vestibular-proprioceptive integration.

This study investigated the effects of exposure to pseudoscientific television (TV) programs upon Taiwanese citizens' pseudoscientific beliefs. The beliefs and practices of pseudoscience portrayed in the media may misguide the citizens in making life choices that may lead to negative consequences. Participants of this study included 2,024 individuals who were selected using probability proportional to size sampling method. Interviews were conducted and survey data were quantitatively analyzed by means of stepwise multiple regressions and reported with the use of cross tables. Results revealed exposure to pseudoscientific TV programs as a strong predictor of Taiwanese citizens' pseudoscientific beliefs and that younger citizens demonstrate more pseudoscientific beliefs and practices than older citizens. Researchers of this study proposed the need for making better use of mass media as a way to educate citizens about science and reduce pseudoscientific beliefs.

The purpose of this quantitative study is to understand the attitudes of Taiwanese adult citizens over 18 years of age toward science and technology. A theoretical model is constructed and evaluated to identify factors that affect public attitudes. Differences in citizens' gender, age, and educational level are also examined to determine whether they parallel differences found in their attitudes. Citizens were selected using probability proportional to size (PPS) sampling. A total of 2,024 valid questionnaires were collected and analyzed by structural equation modeling. The results showed that citizens' scientific knowledge promotes positive attitudes toward techno-scientific issues, which are reflected in their high level of support for scientific development, research and application, as well as recognition of global warming and impression of scientists. Additionally, citizens of different genders, ages, and educational levels have significant differences in their attitudes toward science and technology...

Engine rotational dynamics can be estimated from the tooth signals of the crankshaft wheel. The accuracy of the calculation rises when the number of tooth increases. However, the engine control unit (ECU) needs to detect the tooth position and converts it into time information. It will overload the interrupt system. In order to overcome this problem, the field programmable gate array (FPGA) is proposed to implement the engine rotational dynamics calculation with stroke identification algorithm. The FPGA can accelerate the interpolation and the multiplication processes by implementing them in parallel computation. Thus, the proposed method can calculate the engine rotational dynamics in real time, and then the calculation results can be transferred into the robust Kalman filter which was established by Matlab/Simulink in a computer, i.e., a simulated ECU. Finally, a 125cc scooter is utilized to verify the proposed algorithm. The test results show that the proposed method can be used to obtain precise information of engine rotational dynamics.

The Semi-Direct Injection (SDI) system has been shown to improve small engine efficiency and exhaust by utilizing a lean burn method. In order to better understand how to more readily utilize the control systems in SDI engine, the real-time operation of an SDI engine was modeled. A charging model was developed by using a filling-and-emptying model to simulate air exchange in an engine, including varying the intake manifold structure. A single-zone model was applied to a combustion model and the effects of air/fuel ratio and swirl ratio on combustion duration were also considered. The calculated results of the intake manifold pressure, heat release rate, and cylinder pressure were compared with the experimental data. The results of this study show that this modeling process approximates reality.

PurposeNanoparticles have been studied as additives to lubrication oils for reducing friction and wear. The purpose of this paper is to investigate the effect of nanofluid on engine oil and friction reduction in a real engine.Design/methodology/approachThe nanoparticles were prepared using a high‐temperature arc in a vacuum chamber to vaporize the Ti metal, and then condensed into a dispersant to form the TiO2 nanofluid, which was used as lubricant additive. Experiments were performed in both real engine running and test rig.FindingsIt was found that the engine oil with nanofluid additive with an ethylene glycol dispersant of nanoparticles, had gelled after 10‐h of engine running. The problem of oil gelation (jelly‐like) was solved by replacing the dispersant with paraffin oil. The engine oil with TiO2 nanoparticle additive exhibited lower friction force as compared to the original oil. The experiment showed that a smaller particle size exhibits better friction reduction with particle size ranging from 59 to 220 nm.Research limitations/implicationsThe paper is restricted to findings based on the dispersed nanoparticles in fluid as additive for engine lubrication oil.Practical implicationsThe test results are useful for the application of nanofluid additive for engine oil.Originality/valueMost previous researches in this field were executed on tribotester, rather than the actual engine. This paper describes experimental methods and equipment designed to investigate the application of TiO2 nanofluid as lubricant additive in internal combustion engine.

An adaptive power split control for a rear-wheel-driven hybrid electric scooter (HES) is proposed in this paper. It is designed using the concept of total equivalent fuel consumption. The equivalence factor is used to transform the electric energy into the equivalent fuel energy and is often selected to be a predetermined function of the state of charge (SOC) of the battery. However, the predetermined function might not be optimal for different driving cycles. An adaptive fuzzy sliding mode controller is used to adjust the equivalence factor according to the SOC deviation. An instantaneous cost function, which consists of the total equivalent fuel consumption, is then minimized to obtain the optimal power split between the internal combustion engine and the electric motor. Deterministic dynamic programming (DDP) is used to offer the performance upper bound to benchmark the proposed control strategy. Preliminary results show that suboptimal fuel economy, which is close to the DDP performance, can be achieved for various driving cycles.

The efficiency of an internal combustion engine (ICE) is essential for automobiles and motorcycles. Several studies have demonstrated that the homogeneous charge compression ignition (HCCI) is a promising technology for realizing engines with high efficiency and low emissions. This study investigated the combustion characteristics of the HCCI using a 125 cc motorcycle engine with n-heptane fuel. The engine performance, combustion characteristics, and thermal efficiency were analyzed from experimental data. The results revealed that a leaner air⁻fuel mixture led to higher engine efficiency and output. The improvement of engine output is contradictory to the general trend. Energy balance analysis revealed that lower heat loss, due to the low cylinder gas temperature of lean combustion, contributed to higher efficiency. A double-Wiebe function provided excellent simulation of the mass fraction burned (MFB) of the HCCI. Air cycle simulation with the MFB, provided by the double-Wiebe function, was executed to investigate this phenomenon. The results indicated that a better combustion pattern led to higher thermal efficiency, and thus the engine output and thermal efficiency do not require a fast combustion rate in an HCCI engine. A better combustion pattern can be achieved by adjusting air⁻fuel ratio (AFR) and the rates of dual fuel and exhaust gas recirculation (EGR).

For a conventional scooter engine with a four-plus-one-tooth crankshaft wheel, not only is the crankshaft position estimation insufficient due to poor angle resolution, but the speed measurement might also be easily contaminated by the sensor noise. We proposed a Kalman filter with stroke identification to estimate the engine rotational dynamics. The design of the Kalman filter is based on a kinematic model that requires no engine parameters. A nonlinear engine model is used to evaluate the estimation performance of the conventional algorithm using a low-pass filter and the proposed algorithm at various operating conditions. Preliminary simulation and experimental results show that the proposed algorithm can mitigate the noise impact and result in estimations closer to the actual engine responses.

A heat transfer model for small-scale spark-ignition engines has been proposed by authors in previous study. However, that model was developed based on experimental data of one engine, it may not be so accurate for others. In order to improve the accuracy of predicted heat transfer rate for different engines, a modified heat transfer model using Stanton number based on two engines is proposed. Prediction results of instantaneous heat flux, global heat transfer, heat release rate, and cylinder pressure based on the proposed model are compared with the experimental results of three engines and prediction results of previous model. It is found that the proposed model has prediction results closer to the measured data than the previous models at the most engine operation conditions.

Few studies have specifically investigated the cognitive correlates of employment for persons with mental retardation. To evaluate the relationship of cognitive and adaptive functioning to work status, 56 competitively employed and 55 unemployed individuals with mental retardation underwent a comprehensive neuropsychological and adaptive behavioral evaluation. Results of multivariate analysis of covariance (MANCOVA) revealed significant group differences in cognitive and adaptive behavioral domains controlling for gender and severity of mental retardation. Follow-up ANCOVAs showed that the employed group performed significantly better than the unemployed group on measures of attention, memory, verbal comprehension, visual perception, and adaptive behavior. Using discriminant function analysis, 73.2 percent of the employed and 76.4 percent of the unemployed people were predicted correctly. These results suggest that adaptive behavior and specific aspects of cognitive functioning are significant predictors of successful employment for persons with mental retardation.

In order to satisfy different requirements for engine design and real-time simulation, modulization technology is used in this paper to establish the engine model for small-scale engines. The model consists of simple and complex modules of charging, torque, friction, and crankshaft dynamics, which are established in Matlab/Simulink and verified using the experimental data. Different sets of these modules can be selected for various applications. For engine design, a complex model, which consists of the wave-action charging module and the mean-value combustion module, is employed to study the effects of inlet and exhaust systems on torque output performance. For real-time simulation, different levels of complexity can be selected according to the hardware-in-the-loop requirement of the control verification.

This study examined the tribological properties of two lubricating oils, an API-SF engine oil and a Base oil, with CuO, TiO 2 , and Nano-Diamond nanoparticles used as additives. The friction and wear experiments were performed using a reciprocating sliding tribotester. The experimental results show that nanoparticles, especially CuO, added to standard oils exhibit good friction-reduction and anti-wear properties. The addition of CuO nanoparticles in the API-SF engine oil and the Base oil decreased the friction coefficient by 18.4 and 5.8%, respectively, and reduced the worn scar depth by 16.7 and 78.8%, respectively, as compared to the standard oils without CuO nanoparticles. In addition, investigations were performed using TEM, OM, SEM, and EDX to interpret the possible mechanisms of anti-friction and anti-wear with nanoparticles.

Purpose Carpal tunnel syndrome (CTS) is one of the most common hand problems and a major cause of work disability. The purpose of this study was to use confirmatory factor analysis (CFA) to assess the factor structure of the Boston Carpal Tunnel Questionnaire (BCTQ) in patients with CTS. Methods One hundred and twenty-three patients with CTS were recruited from two hospitals. Each patient completed the functional status scale and the symptom severity scale of the BCTQ. CFA was used to assess the model fit between the data and pre-established theoretical measurement models. Results CFA showed that all three-factor models were better than the original two-factor model. Among the three-factor models, the simplified model, with 11 items assessing daytime pain, nocturnal numbness/tingling, and hand function was the best, for the model fit the data better than did the other models. Specifically, the Comparative Indices were larger than 0.95 (Tucker–Lewis Index and Comparative Fit Index values), and the Absolute Fit Indices and information-theoretic measures were the smallest. Moreover, all factor loadings were significant and high in magnitude (ranging from 0.66 to 0.99), the composite reliabilities exceeded 0.60 (ranging from 0.78 to 0.94), and the average variance extracted exceeded 0.50 (ranging from 0.61 to 0.89). Conclusion The simplified model showed the highest reliability and validity, and the factor structure was the simplest/clearest one. The simplified model is recommended for clinical use due to its convenience and precision for assessing the problems of patients with CTS.

The heat transfer models proposed in previous studies are not suitable for small-scale spark-ignition engines, because they were developed primarily for large-scale engines. In order to improve the accuracy of the predicted heat transfer rate for small-scale engines, a heat transfer model using the Stanton number is proposed in this paper. Prediction results of instantaneous heat flux, global engine heat transfer, and cylinder pressure based on the proposed model are compared with the experimental results and prediction results of previous models. It is found that the proposed model has prediction results closer to the measured data than the previous models at most engine operating conditions.

In order to study the effect of the crank sensor noise on the engine management system (EMS), an algorithm using a closed-loop estimator with stroke identification is proposed to estimate the engine rotational dynamics. Estimated crank angle and engine speed are used for fuel injection and ignition control systems. The closed-loop estimator design is based on a linear model by assuming that the engine rotational inertia is constant. Since the effective inertia actually varies with different crank angles, the stability of the proposed algorithm is assessed using the Lyapunov stability theorem. Performances of the proposed and traditional algorithms are evaluated using a non-linear engine model with a four-plus-one-tooth crankshaft wheel in Matlab/Simulink. The estimated crank angle and engine speed of the traditional algorithm can be significantly affected by large sensor noises resulting from the poorly grounded ignition coil. It was found that the proposed algorithm can mitigate the noise impact and thus maintain the desired engine control performance.

Five step cone gurations were designed to investigate the effects of inlet step cone gurations on the e ow structure and ignition of solid fuel behind a backstep. Experiments were conducted separately in a cold e ow for the e owe eld measurement and in a hot e ow for the fuel regression before ignition and ignition tests. The step height was e xed at 29 mm for each cone guration. The inlet velocity of the cold e ow was 15 m/s. The velocity e owe eld was measured with a laser Doppler anemometer and the ignition process was observed with a video camera. The cone guration of the inlet step signie cantly affected the turbulence intensity of the shear layer and the reverse e ow rate of the recirculation zone. The greater reverse e ow rate provided a better e ameholding capability, and hence, abbreviated the ignition delay. As the e ow was turbulent, the higher the turbulence intensity and the longer the ignition delay. When the oxygen concentration was higher than 19%, the effect of inlet cone guration on ignition diminished.

Applying lean burn for motorcycle engines is a preferred solution to reduce fuel consumption and exhaust pollutants. It is however difficult to use conventional air/fuel control solutions for a lean-burn engine as the fuel duration is controlled to achieve desired torque, while airflow is controlled by the throttle valve to maintain air/fuel ratio demand. So for lean-burn motorcycle engine, the throttle valve must be automatically controlled depending on airflow requirement. However airflow cannot be controlled directly by throttle position due to high error. Since the airflow is closely related to the manifold pressure, this paper proposes an adaptive controller for pressure intake manifold control of a motorcycle engine using an electronic throttle valve control. The throttle position is employed as the control input for maintaining desired intake manifold pressure, and is designed based on a lead-lag compensator. The speed-density solution is employed to estimate the parameter of dynamic model. The root-locus technique is used to design the adaptive controller. Performance of the proposed controller is evaluated using a nonlinear motorcycle engine model in matlab/Simulink and experimental validation.

This paper discusses the design, modeling, and development of small motorcycle equipped with a HCCI engine in an series hybrid configuration. A mathematical model was developed using MATLAB/Simulink and used to size the powertrain components and to predict fuel economy. A conventional 125 cc spark ignition engine was modified to run in HCCI combustion mode and integrated into a prototype vehicle. Dual-fuel and external EGR strategies were used to upgrade the engine speed and torque capabilities of the engine to meet the requirements of the powertrain. An electrical generator, hub-motor, battery pack and other power electronics devices were used to form the electrical system for the vehicle. The advantages of the proposed design compared to the original motorcycle with SI engine and CVT transmission are: 1) a reduction in noxious emissions due to the HCCI combustion, and 2) higher fuel economy in city driving because of the HCCI engine and series hybrid powertrain. Fuel economy was measured by driving the motorcycle on a chassis dynamometer using a sequence of ECE-40 driving cycles. The overall fuel economy was measured to be 73.7km/L which represents a 139.3% increase in fuel economy over the baseline vehicle.

Ignition of solid fuel by a hot oxidizing flow in a sudden-expansion combustor was investigated experimentally. The controlled variables of the experiments were concentration of oxygen (12-25%), gas temperature (750-850 C), and flow velocity (19-46 m/s). The step height was 29 mm. The corresponding Reynolds numbers based on the flow velocity and the step heights were 12 x 10(sup 4)-31 x 10(sup 4). The controlling mechanisms of ignition in the flow with abundant oxygen were distinct from those with little oxygen. The initial flame kernels formed near the reattachment point and adjacent to the surface of solid fuel when the oxygen concentration was large. The process was controlled by diffusion and the ignition delay decreased with increased flow velocity. For the flow containing oxygen at a small concentration, the initial flame kernels formed within the recirculation zone and away from the surface of the solid fuel. The process was then controlled by the chemical kinetics and the ignition delay increased with increased flow velocity. 15 refs.

The transient regression and ignition of a solid fueld in a hot-oxidizing flow in a simulated combustor of a solid-fuel ramjet (SFRJ) were experimentally investigated. The local regression of solid fuel was measured at various intervals before ignition, and the controlled variables of the experiments were the inlet flow velocity, gas temperature, oxygen content, and step height. The maximum regression was located at 5.0–5.5 step heights from the entrance. The results of regression tests indicate that the influence of heat transfer was more important than the flow structure of the separated-reattaching flow. The regression rate increased with increasing the flow temperature and mass flow rate but decreased with increasing step height. The oxygen content had no significant influence on the regression before ignition. The transport phenomena in the combustor before ignition were closely related to the ignition mechanisms, which were diffusion control and chemical kinetics control. Diffusion control applied in the region of oxygen concentration greater than 20%, and the ignition delay decreased as pyrolyzed fuel vapor increased during the preignition period. Chemical kinetics control applied in the region of oxygen concentration less than, 15%, and the flow feature of flame stabilization was more important than pyrolysis for decreasing the ignition delay.

This study used nationwide data from the Taiwan Education Panel Survey (TEPS) to examine the longitudinal effects of educational expectations and achievement attributions on the academic achievements of adolescents. The sample included 2,000 Taiwanese secondary school students, each of whom completed three waves of questionnaires and cognitive tests: the first in grade 7 (in 2001), the second in grade 9 (in 2003), and the third in grade 11 (in 2005). Through multilevel longitudinal analysis, the results showed: (1) educational expectations accounted for a moderate amount of the variance in academic achievements; (2) students with high educational expectations and effort attribution exhibited higher growth rates in their academic achievements; and (3) studentswith lower educational expectations and those attributing success to others showed significantly fewer academic achievements and significantly lower growth rates in such achievements. The results demonstrated that adolescents' educational expectations and achievement attributions play crucial roles in the long-term course of academic accomplishments. Implications for educational practice and further studies are also discussed.

Homogeneous charge compression ignition (HCCI) is recognized as an advanced combustion system for internal combustion engines that reduces fuel consumption and exhaust emissions. This work studied a 150 cc air-cooled, four-stroke motorcycle engine employing HCCI combustion. The compression ratio was increased from 10.5 to 12.4 by modifying the cylinder head. Kerosene fuel was used without intake air heating and operated at various excess air ratios (λ), engine speeds, and exhaust gas recirculation (EGR) rates. Combustion characteristics and emissions on the target engine were measured. It was found that keeping the cylinder head temperature at around 120–130°C is important for conducting a stable experiment. Two-stage ignition was observed from the heat release rate curve, which was calculated from cylinder pressure. Higher λ or EGR causes lower peak pressure, lower maximum rate of pressure rise (MRPR), and higher emission of CO. However, EGR is better than λ for decreasing the peak pressure and MRPR without deteriorating the engine output. Advancing the timing of peak pressure causes high peak pressure, and hence increases MRPR. The timing of peak pressure around 10–15 degree of crank angle after top dead center indicates a good appearance for low MRPR.

Homogeneous charge compression ignition (HCCI) is a well-known technology that reduces the fuel consumption and exhaust emissions. This work implemented HCCI on a 150cc spark-ignition (SI) engine. The compression ratio of target engine was changed from 10.5 to 12.4 to enhance the compression temperature. In addition, a commercialized low-pressure injector was installed near the intake port for supplying fuel for HCCI operation. After the analysis of in-cylinder gas temperature, the dual fuel, with gasoline for the additive fuel and kerosene as the main fuel, was investigated in the small scale target engine. Experiments were executed through various excess air ratios, different gasoline additive ratios and then extension of engine load. Two-stage heat release, which provides energy to heat up the mixture during the compression stroke, was observed from HCCI combustion with kerosene fuel. The maximum rate of pressure rise (MRPR) could be reduced by increasing gasoline additive ratio of dual fuel without deteriorating the engine power output. By using the dual fuel method, the engine indicated mean effective pressure could be improved by a maximum percentage 23.9% and an average percentage 17.6% from just using kerosene fuel under the knocking limitation of MRPR equals to 4 bar/deg.Copyright © 2010 by ASME

Homogeneous charge compression ignition (HCCI) is recognized as an advanced combustion system of internal combustion engine for reducing fuel consumption and exhaust emissions. This paper studied a 150 cc air-cooled four-stroke motorcycle engine operating HCCI combustion. The compression ratio was increased from 10.5 to 12.4 by modifying the cylinder head. The kerosene fuel was used without intake air heating and operated at various excess air ratios (λ), engine speeds, and EGR rates. The combustion characteristics and emissions on the target engine were measured. It was found that keeping the cylinder head temperature at around 120–130°C is important for stable experiment. Two-stage ignition was observed from the heat release rate curve, which was calculated from the cylinder pressure. Higher first stage ignition temperature causes higher peak cylinder gas temperature. Higher λ or EGR causes lower peak pressure, lower maximum rate of pressure rise (MRPR), and higher emission CO. However, EGR is better than excess air for decreasing the peak pressure and MRPR without deteriorating the engine output.Copyright © 2009 by ASME