Fiber reinforced composites of a novel pendent polyimide: Optimum processing and mechanical properties

A 2-component polyimide [3,4\u27-ODA + 4,4\u27-ODPA], a 3-component parent polyimide [3,4\u27-ODA + 4,4\u27-ODPA + 10 mol % Mellitic acid dianhydride (MADA)] and a 4-component pendent polyimide [3,4\u27-ODA + 4,4\u27-ODPA + 10 mol % MADA + 10 mol % Zr] were synthesized and characterized using fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) techniques. Since temperature and time are critical factors influencing the thermal and mechanical properties of the final polyimide, it is important to have detailed information on the best time-temperature conditions for imidization and cure in order to optimize the processing and properties of this polyimide. The present investigation focused on developing these conditions for the polymer. The processing condition of heating the poly(amic acid) at 310 C for 15 minutes was chosen as an optimum processing condition for the Zr-pendent polyimide. The sample showed complete imidization without any decomposition at the given processing temperature. The polyimide resins were also investigated as a matrix for high performance composites. Prepregs were fabricated using the conventional hand lay-up technique. Carbon and/or glass fiber reinforced composite laminates were fabricated in an autoclave to obtain a 60:40 fiber to resin by weight ratio. Tensile, flexural, Izod impact and dynamic mechanical analysis tests were carried out on the composite laminates. Mechanical properties of the pendent polymer were compared with those of the parent (without pendent groups) polyimide. Failure mechanisms were studied through the use of optical and scanning electron microscopy. The Zr-pendent polyimide composites showed lower moduli for the mechanical tests performed as compared to the 2-component and parent polyimide composites. Comparisons of mechanical data with laminates fabricated using a different molding cycle are also included

Helping struggling writers through self-regulated strategy development

The purposes of this action research was to determine the effectiveness of implementing a self-regulated strategy development model to teach a story writing strategy to three 3rd grade students at a New Jersey Elementary School. This study involved a comparison of stories written by students before and after self-regulated strategy development instruction. Students chosen to participate in the study lacked proficiency in story writing and held negative beliefs towards writing in general. All participants completed a Pre-SRSD Story Writing task, which was holistically scored to determine student ability in story writing. The Pre-SRSD Story Writing task was submitted prior to SRSD instruction and compared with the Post-SRSD Story Writing task which was completed after SRSD instruction one week later. The Post-SRSD Story Writing task was holistically scored and analyzed using a rubric to determine whether the writing ability of participants improved as a result of SRSD instruction. Results of this analysis showed that SRSD did improve writing proficiency of low writing ability students

Multiprocessor system design tutor : expert system approach

To increase computational bandwidth and system resilience, integration of several microprocessors in a single system becomes necessary. The overall throughput and efficiency of such a system is directly dependent on the hardware and software interconnection supported by the basic microprocessor chip. Sometimes it becomes difficult to put together all the information for design criteria and all the design related formulas. The approach made here is to continuously update the hardware and software information in the database related to a given microprocessor. This information can be accessed at any time for efficient design solution. Intel 80386 and Motorola 68020 microprocessors are reviewed in detail and all the information is stored in a database. The above approach has been implemented in the Multiprocessor System Design - Tutor (MSDT) using the Informix relational database management system. MSDT is a menu driven system implemented to help the system design engineers. MSDT stores and maintains information related to multiprocessor system design, which includes multiprocessor system requirements, microprocessor characteristics, the role of microprocessor in multiprocessor system design and interconnection network configurations and their performance factors. This information is presented to the user via the screen building utility of Informix-4GL; the user can also get a hard copy of all the information within the database by running the report generation utility. MSDT also has security password protection. The system has a good help facility available for the design process. At any given time the user can update the data in the table using this menu driven system. The system is intended to grow into a complete evaluation system based on the Informix-4GL. It is developed on the basis of Fourth Generation Language which has a screen building utility, a menu building utility, a report writer and a window manager. This system will suggest the candidate microprocessor and suitable support chips and interconnection techniques for different applications

Bridging the Gap between Food Insecurity and Subsequent Child Body Mass: Mediating Effects of Dietary Quality and Feeding Styles in Low-Income Hispanic Preschoolers

Background: Low-income Hispanic preschoolers face disproportionately high prevalence of food insecurity (FI) and obesity. Consumption of low-cost, energy-dense foods to compensate for FI leads to excess body-mass. FI parents may adopt feeding styles that contribute to decline in children’s dietary quality. Feeding style describes the amount of demandingness (i.e., control of children’s eating) and responsiveness (i.e., warmth used to express demandingness). FI may indirectly contribute to obesity through dietary quality and feeding style. Purpose: This study investigated: 1. if dietary quality mediated the relationship between food security status (FSS) at Time 1 (T1) and child body-mass at Time 2 (T2), 2. if feeding demandingness (PFD) and/or responsiveness (PFR) mediated the relationship between FSS at T1 and child dietary quality at T2, 3. explored if gender and/or parental acculturation moderated the mediation. Method: The current study was a secondary analysis of an observational study (R01 HD06257, PI: Hughes). Hispanic parent-preschooler dyads (n=137) provided data through the 6-item Household Food Security Survey, Healthy Eating Index-2015 (HEI), Caregiver’s Feeding Style Questionnaire, Bidmensional Acculturation Scale, and body-mass-index z-score (BMIz) at two timepoints 18 months apart. Mediation and moderated mediation analyses were conducted using regression models while controlling co-variates. Bias-corrected bootstrap confidence intervals estimated indirect effects. Outcomes: FSST1 did not indirectly influence child BMIzT2 through HEIT1 (ab= -0.00, bootstrap CI [-0.15, 0.03]). FSST1 also did not indirectly influence HEIT2 through PFDT1 (ab= -0.01, bootstrap CI [-0.15, 0.03]) or PFRT1 (ab= 0.01, bootstrap CI [-0.04, 0.14]). However, as FSST1 worsened, HEI-2015T2 improved (c= 1.06, 95% CI [0.43, 1.69]). As a co-variate, higher baseline English acculturationT1 predicted lower HEI-2015T2 (β= -3.44, 95% CI [-5.62, -1.26]) and higher BMIzT2 (β= 0.13, 95% CI [0.05, 0.21]); however, it did not have significant conditional effects in moderated mediation models. Gender (pFSSxGender= .04) moderated the direct effect of FSST1 on BMIzT2; however, effect size ((β= 0.05, 95% CI [0.002, 0.09]) was too small to be clinically relevant. Conclusion: FI did not affect body-mass through dietary quality, nor did it affect dietary quality through PFD or PFR. However, an unexpected positive direct relationship between FI and subsequent dietary quality warrants further exploration

Sensory and cognitive contributions to speech perception in background noise in young adults

In the present study, speech perception in background noise was investigated by asking participants to perform listening tasks in two target speech contexts. Each target speech context was presented in four listening environments. External factors within each listening environment were manipulated, and various internal factors of the listener were subsequently measured. The primary aim of this study was to determine how well sensory and cognitive functions predict speech perception in noise outcomes for various target speech contexts presented in different types and levels of background noise. While this study did not reveal a significant effect for seven of the nine sensory and cognitive variables, this does not suggest that speech perception in noise does not involve a broad range of sensory and cognitive abilities. It’s possible that even when individual difference among listeners exist, the sensory and cognitive abilities of most young normal hearing individuals are suitable for the purpose of speech perception in noise.Communication Sciences and Disorder

Design and Manufacturing of a Mecanum Wheel for the Magnetic Climbing Robot

An AndyMark Mecanum Wheel has been re-designed for better performance and utilization by Helical Robotics. Mecanum Wheel is a complex Omni-Directional wheel that currently contains several drawbacks. The drawbacks include design, usage of hobby grade material, bumps in rollers, etc. A comprehensive design of the Mecanum wheel is being presented using Computer Aid Software, CAD and analysis tools, such as Finite Element Analysis, FEA. The different concepts were hand sketched using various parameters and then implemented in a CAD software-- CATIA. The Mecanum Wheel\u27s feasibility was thoroughly studied through ANSYS software. Load analysis was performed using various materials and several manufacturing processes carefully, to check the achievability of the wheel. In conclusion, the Mecanum wheel was successfully re-designed and manufactured to meet the requirements and specifications of Helical Robotics

સ્વામિનારાયણ સંપ્રદાયની મધ્યકાલીન ગુજરાતી કૃષ્ણકવિતા - એક સમીક્ષાત્મક અધ્યયન

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TLR1-induced chemokine production is critical for mucosal immunity against Yersinia enterocolitica.

Our gastrointestinal tract is a portal of entry for a number of bacteria and viruses. Thus, this tissue must develop ways to induce antigen-specific T cell and antibody responses quickly. Intestinal epithelial cells are a central player in barrier function and also in communicating signals from invading pathogens to the underlying immune tissue. Here we demonstrate that activation of Toll-like receptor 1 (TLR1) in the epithelium leads to the upregulation of the chemokine CCL20 during oral infection with Yersinia enterocolitica. Further, both neutralization of CCL20 using polyclonal antibody treatment and deletion of TLR1 resulted in a defect in CCR6+ dendritic cells (DCs), which produce innate cytokines that help to induce anti-Yersinia-specific T helper 17 (TH17) cells and IgA production. These data demonstrate a novel role for TLR1 signaling in the intestinal epithelium and demonstrate that together TLR1 and CCL20 are critical mediators of TH17 immunity through the activation and recruitment of DCs