Influence Of Processing Speed Research Articles

Executive Function and Processing Speed in Children Living with Sickle Cell Anemia.

Executive function and processing speed difficulties are observed in children living with sickle cell anemia (SCA). The influence of processing speed on executive function is not well understood. We recruited 59 children living with SCA and 24 matched controls aged 8-18 years between 2010 and 2016 from clinics in the UK. Children completed tests in processing speed and cognitive flexibility, subdomains of executive function. MRI scans were conducted within one year of testing; oxygen saturation was obtained on the day of testing. Hemoglobin levels were obtained from medical records. Caregivers completed the executive function questionnaire. Hierarchical linear regressions found that hemoglobin, oxygen saturation, age, infarct status, and processing speed were not independent predictors for any model. However, for all cognitive flexibility tests, there was a significant interaction between infarct status and processing speed; children without silent cerebral infarction (SCI) with faster processing speed had better cognitive flexibility. Our findings indicate that, when interpreting executive function difficulties, it is important to account for the relationship between SCI status and processing speed. More research is needed to elucidate the mechanisms, but clinically, including executive function testing as part of clinic visits by embedding psychologists within the healthcare team would appear to be a critical step.

Study on the Influence of the Processing Speed in the Generation of Complex Geometries in Aluminium Matrix Composites by Electrochemical Precision Machining

Currently, an increasing demand for lightweight materials with a high strength can be observed. Potential materials, which fulfil these requirements, are particle reinforced aluminium matrix composites (AMCs). AMCs consist of an aluminium matrix, which is reinforced by ceramic particles. In a consequence, AMCs offer a strength, which is comparable to steel, along with a density, which is comparable to light metals. In the Collaborative Research Centre SFB 692 at Chemnitz University of Technology, AMCs are analysed under different research aspects. One of these aspects is the generation of complex geometries by Electrochemical Precision Machining (PECM).The investigated AMC consists of ENAW 2017, which is reinforced by 10% of SiC-particles. To achieve the desired complex geometry, the dissolution characteristic of the specific AMC was analysed. Furthermore, the achievable surface quality was characterised. Based on these fundamental results, processing strategies for generating complex geometries in AMCs by PECM were derived.In this study, the influence of the PECM processing speed on the resulting complex geometry is investigated. For that purpose, a model geometry based on a retarder was selected and realized. The resulting side gap and the front gap as a function of an increasing processing voltage and an increasing feed rate are presented. It can be stated that the side gap can be reduced by an increase in feed rate.

Influence of Processing Speed on Microstructure and Mechanical Properties of ZK60 Magnesium Alloy Prepared by Friction Stir Processing

Influence of Processing Speed on Microstructure and Mechanical Properties of ZK60 Magnesium Alloy Prepared by Friction Stir Processing

Polystyrene cellulose fiber composites: effect of the processing conditions on mechanical and dynamic mechanical properties

The usage of natural fibers on the composites development has grown rapidly in the recent years due to the fibers plentiful availability, renewable source, low density and biodegradability. However, there are some drawbacks, for instance, the fiber dispersion on a polyolefin matrix. In this work, the influence of processing speed on the mechanical and dynamic mechanical properties of polystyrene (PS) filled with cellulose fiber composites was investigated. The composites were processed on a twin-screw co-rotating extruder, using screw speeds of 200 rpm, 400 rpm and 600 rpm. The dynamic mechanical properties and the mechanical properties were investigated as a function of fiber content. The composites processed on a screw speed of 400 rpm had presented an increase on flexural and impact strength, compared to the composites processed at 200 rpm. The flexural and storage modulus had increased when increasing the fiber content, as well as increasing the processing speed. The greater fiber dispersion obtained at a screw speed of 400 rpm hinders the agglomeration arrangement and distributes the fibers more equally on the matrix. The increase on processing speed probably generates a fiber size reduction, increasing the fiber superficial area and generating a greater contact with the matrix as well. Therefore, the efforts transference of matrix to fibers is improved, originating an increase on the evaluated properties.

Influence of processing speed on microstructures and mechanical properties of friction stir processed Mg–Y–Nd–Zr casting alloy

Mg–3·99Y–3·81Nd–0·53Zr (WE43) casting alloy was subjected to friction stir processing (FSP) at a constant rotation rate of 800 rev min−1 and various processing speeds of 30, 60, 90 and 120 mm min−1, and microstructures and mechanical properties of the experimental materials were investigated. With the processing speeds increasing, the average grain size first decreases and then increases, and the finest microstructure (∼2 μm) is prepared at the processing speed of 60 mm min−1. Owing to much finer microstructure, the mechanical properties of the WE43 alloy after FSP are significantly improved. The maximum tensile strength and elongation of the FSP WE43 alloy obtained at 60 mm min−1 are 290 MPa and 17·2% respectively. The fracture morphology shows that fine dimples and tearing edges can be observed on the FSP specimens. In addition, high temperature tensile tests show that the FSP WE43 alloys exhibit excellent high strain rate superplasticity, with a large elongation of 631% at 748 K at a strain rate of 2×10−2 s−1.

Effect of Processing Speed on Microstructures and Mechanical Properties of Submerged Friction Stir Processed AZ91 Alloy

Normal and submerged friction stir processing (SFSP) were conducted to AZ91 magnesium alloy plates with 6mm in thickness, and influence of processing speed (ν) on microstructures and mechanical properties of the experimental materials was investigated. The results revealed that fine and equiaxed grains were observed in the stirred zone (SZ). As the processing speed increased from 60mm/min to 150mm/min, the average grain size in the SZ of normal FSP material decreased. However, the grain size of the SFSP specimens first increased with the processing rate increasing from 60mm/min to 120mm/min, and then decreased when the processing rate increased to 150mm/min. Microstructure of the SFSP specimen was much finer compared with the normal FSP one, and the grain size of α-Mg was about 1.2µm when the processing speed was 60mm/min during SFSP. Because of much finer microstructure of SFSP, the microhardness, tensile strength and elongation were all improved. SEM fracture observation showed that fine dimples and tearing edges could be observed on SFSP specimen which showing good ductility. In addition, high temperature tensile tests showed that SFSP AZ91 alloys exhibited excellent superplasticity at high strain rate, with an elongation of 1202% at 623 K with a strain rate of 3x10-3s-1. The present study demonstrated that SFSP possesses great potential in preparing fine-grained materials.

Domain‐specific and domain‐general precursors of mathematical achievement: A longitudinal study from kindergarten to first grade

Many contributing factors, both domain specific and domain general, influence children's performance in school achievement. This research aims to verify the importance of kindergarten measures of cognitive abilities and numerical competence in the role of predicting mathematical school achievement at the end of first grade. A total of 70 children (38 females and 32 males) took part in the study. We tested the children at the beginning of their last year of kindergarten (time 1) on the following cognitive abilities: IQ, phonology, counting skills, verbal short-term memory, visuo-spatial short-term memory, working memory, and processing speed. Then, we tested the same children at end of their last year of kindergarten (time 2) on a measure of numerical competence and at the end of their first year of primary school (time 3) on a test of math achievement. Path analysis models revealed the direct influence of working memory and processing speed on predicting numerical competence in pre-schoolers and the influence of processing speed and verbal IQ on predicting math achievement in first graders. Moreover, this study found a direct link between numerical competence and math achievement. Both domain-specific and domain-general factors contribute to determining math achievement at the end of first grade.

Influence of processing speed on adult age differences in working memory

Two studies are reported in which adults ranging from 18 to 80 years of age performed tasks designed to measure working memory functioning and perceptual comparison speed. The results from both studies indicated that statistical control of the measures of perceptual comparison speed greatly attenuated the age-related variance in measures of working memory even when working memory was assessed under self-paced conditions. Additional results in the second study supported the hypothesis that the speed influence was manifested in the rate of activating information rather than in the rate at which it was lost as a function of time or other processing.