Quantitative measures for assessment of the hydraulic excavator digging efficiency

In this paper, quantitative measures for the assessment of the hydraulic excavator digging efficiency are proposed and developed. The following factors are considered: (a) boundary digging forces allowed for by the stability of an excavator, (b) boundary digging forces enabled by the driving mechanisms of the excavator, (c) factors taking into consideration the digging position in the working range of an excavator, and (d) sign and direction of potential digging resistive force. A corrected digging force is defined and a mathematical model of kinematic chain and drive mechanisms of a five-member excavator configuration was developed comprising: an undercarriage, a rotational platform and an attachment with boom, stick, and bucket. On the basis of the mathematical model of the excavator, software was developed for computation and detailed analysis of the digging forces in the entire workspace of the excavator. By using the developed software, the analysis of boundary digging forces is conducted and the corrected digging force is determined for two models of hydraulic excavators of the same mass (around 17 000 kg) with identical kinematic chain parameters but with different parameters of manipulator driving mechanisms. The results of the analysis show that the proposed set of quantitative measures can be used for assessment of the digging efficiency of existing excavator models and to serve as an optimization criterion in the synthesis of manipulator driving mechanisms of new excavator models.     

Dynamic behavior of a hydraulic crane operating a freely suspended payload

We describe an investigation of the dynamic behavior of a hydraulically driven crane with a freely suspended payload during luffing and slewing motions. To simplify the task, the two movements are considered separately. Taking into account only one motion at a time, the crane is regarded as a three-link kinematic chain with revolute joints. The forward dynamics problem is solved for a crane with three rotational degrees of freedom, two of which describe the load swinging. In both the cases studied, the links are driven by a torque applied via a hydraulic drive, i.e., a linear actuator for the luffing case and a rack and pinion mechanism for the slewing motion. To compose the set of differential equations for the forward dynamics problem, a method based on a general Newton-Euler algorithm is used. From these simulations the time histories of various parameters, namely the swinging angles, hydraulic pressures, and joint forces, are determined. The results obtained via simulations are confirmed experimentally and a good agreement between the two outputs is observed. The results also show that a hydraulic drive system using fast opening flow direction control valves increases the load swing and imposes extensive inertial forces and problems of fatigue and reliability.     

SURVEY OF JEWISH EDUCATION IN NEW YORK CITY

This case study examines the contours of culturally relevant pedagogy in an undergraduate preservice teacher education program for Jewish women. The case describes how the assigned reading of Albarelli’s (2000) narrative of teaching in a Hasidic Jewish school, Teacha! Stories from a Yeshiva, disrupts the classroom community, diminishes student engagement with the course, and undermines student confidence in the instructor. This research explores what happens when “respect for” challenges “reflection about.” The study finds that differential cultural understandings surrounding the concept of “respect” mediate the discourse. The author raises questions about the ethics of social justice in religious teacher education, probes the poverty of educational reform in a landscape of nondiscussables, and offers strategies for navigating this tender terrain.     

The role of stroke knowledge in reading and spelling in Chinese

The present study examined the types of orthographic knowledge that are important in learning to read and spell Chinese words in a 2‐year longitudinal study following 289 Hong Kong Chinese children from Grade 1 to Grade 2. Multiple regression results showed that radical knowledge significantly predicted children's word reading and spelling performance across the years. Stroke knowledge contributed both concurrently (Grade 1) and longitudinally (Grade 2) to children's spelling performance after controlling for rapid naming, phonological awareness, morphological awareness and radical knowledge. These findings support the significance of radical knowledge in Chinese reading and spelling and the specific role of stroke order knowledge in Chinese spelling. The findings have implications for the design of an effective curriculum for teaching children to spell Chinese characters.     

Loneliness,friendship quality and the social networks of adolescents with high‐functioning autism in an inclusive school setting

By definition, children with autism have poor peer relationships despite age and ability. When children enter adolescence, social problems typically worsen and feelings of loneliness and isolation may emerge. Thus, the overarching goal of the current study is to examine the social–emotional relationships of adolescents with autism and their typically developing (TD) classmates. Participants included 20 adolescents, 7 adolescents with autism and 13 TD classmates. All participants were enrolled in a drama class at a regular education high school in the Los Angeles area. Results indicate that adolescents with autism experienced significantly more loneliness than their TD classmates, had significantly poorer friendship quality in companionship and helpfulness, and had significantly lower social network status than their TD classmates. In addition, 92.4% of TD adolescents had secondary or nuclear social network centrality, which means that those adolescents were significantly connected and recognised in their classroom social structure although 71.4% of the adolescents with autism were either isolated or peripheral in their classroom. These findings imply that although inclusion in regular classrooms may allow adolescents with autism to be involved in the social structure of their classroom, they experienced more loneliness, poorer friendship quality and social network status as compared with their classmates. These results suggest that, perhaps, more intensive social skills' interventions that focus on friendship development are needed in adolescents with autism.     

Name Writing: A Window into the Emergent Literacy Skills of Young Children

This article discusses the potential significance of name writing skills in addressing many important questions about the development of early literacy skills. Young children are inherently interested in producing their own names in print. Furthermore, young children appear to construct their understandings of name writing skills in a predictable, sequential pattern. Questions raised include whether the development of name writing skills mirrors the development of other important cognitive skills, the potential of name writing skills to offer insight as to how young children learn important literacy concepts, the use of name writing as a developmental indicator for children that may be at risk for reading difficulties, and the potential for structured activities using name writing to facilitate the development of emergent literacy skills.     

Supervisor Cultural Humility Predicts Intentional Nondisclosure by Post-Master's Counselors

The authors examined supervisor cultural humility as a predictor of supervisee intentional nondisclosure. Using multiple regression in a sample of 101 post-master's counselors, the authors found that 20% of supervisees' intentional nondisclosure was explained by their perceptions of their supervisors' level of cultural humility.     

Improving Reading Comprehension through Holistic Intervening and Tutoring During After-School with High Risk Minority Elementary School Students

The current study took a quasi-experimental approach investigating the effect of a holistic after-school intervention, on reading comprehension measured by the Gray Oral Reading Test (GORT)-4 on at-risk students in Grade 2 through Grade 5. Analysis of Variance was used to investigate the relationship between pre- and post-intervention scores. The study showed encouraging results. The 91 student participants showed gains in their GORT-4 total scores after the intervention. Results of after-school tutoring lend support to the use of peer-tutoring in afterschool in the elementary schools. Due to the exploratory nature of the study in a single school, there are constraints on generalizability and utility of findings to other schools across the board.     

Training in phonological strategies improves Chinese dyslexic children’s character reading skills

This study investigated Chinese dyslexic children’s efficiency in employing phonological strategies (i.e. the use of orthography-phonology correspondence rules) in reading and the effectiveness of training phonological strategies in improving Chinese dyslexic children’s reading performance. An Experimental Group of 15 Chinese dyslexic children received a five-day intensive training in phonological strategies while a comparable Control Group did not. The results showed that Chinese dyslexic children did not use the phonological strategies as efficiently as Chinese average readers, and the training programme was effective in significantly improving the Experimental Group’s reading performance. This suggests that Chinese dyslexic children can benefit from training in phonological strategies.