Soft Core/Shell Packages for Stretchable Electronics

This paper presents materials and core/shell architectures that provide optimized mechanical properties in packages for stretchable electronic systems. Detailed experimental and theoretical studies quantitatively connect the geometries and elastic properties of the constituent materials to the overall mechanical responses of the integrated systems, with a focus on interfacial stresses, effective modulus, and maximum extent of elongation. Specific results include core/shell designs that lead to peak values of the shear and normal stresses on the skin that remain less than 10 kPa even for applied strains of up to 20%, thereby inducing minimal somatosensory perception of the device on the human skin. Additional, strain‐limiting mesh structures embedded in the shell improve mechanical robustness by protecting the active components from strains that would otherwise exceed the fracture point. Demonstrations in precommercial stretchable electronic systems illustrate the utility of these concepts.     

Brain mechanisms for reading and language processing in spina bifida meningomyelocele: A combined magnetic source- and structural magnetic resonance imaging study.

Objective: The development of the ability to process spoken and written language depends upon a network of left hemisphere temporal, parietal, and frontal regions. The present study explored features of brain organization in children with spina bifida meningomyelocele (SBM) and shunted hydrocephalus, who commonly present with precocious development of word reading skills and preservation of vocabulary and grammar skills. Method: Eight children with SBM were compared with 15 IQ and reading-level matched, typically developing controls on MRI-based morphometric and Magnetic Source Imaging-derived neurophysiological profiles. Results: Children with SBM showed reduced magnetic activity in left inferior parietal regions during spoken word recognition and pseudoword reading tasks. We also noted reduced surface area/volume in inferior parietal and posterior temporal regions in SBM and increased gray matter volumes in left middle frontal regions and gyral complexity in left posterior temporal and inferior parietal regions. Conclusions: A complex pattern of changes in cortical morphology and activation may serve as evidence for structural and functional brain reorganization ensuring preservation of language and decoding abilities in children with SBM. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Preparation of granular activated carbon from oil palm shell by microwave-induced chemical activation: Optimisation using surface response methodology

In this study, waste palm shell was used to produce activated carbon (AC) using microwave radiation and zinc chloride as a chemical agent. The operating parameters of the preparation process were optimised by a combination of response surface methodology (RSM) and central composite design (CCD). The influence of the four major parameters, namely, microwave power, activation time, chemical impregnation ratio and particle size, on methylene blue (MB) adsorption capacity and AC yield were investigated. Based on the analysis of variance, microwave power and microwave radiation time were identified as the most influential factors for AC yield and MB adsorption capacity, respectively. The optimum preparation conditions are a microwave power of 1200 W, an activation time of 15 min, a ZnCl₂ impregnation ratio of 1.65 (g Zn/g precursor) and a particle size of 2 mm. The prepared AC under the optimised condition had a BET surface area (S_BET) of 1253.5 m²/g with a total pore volume (V_tot) of 0.83 cm³/g, which 56% of it was contributed to the micropore volume (V_mic).     

Is there an association between intradialytic hypotension and serum magnesium changes?

Intradialytic hypotension (IDH) is the most common complication of hemodialysis (HD). The aim of this study was to investigate the significance of intradialytic changes of serum magnesium (sMg) and its relation to IDH. We considered 58 patients undergoing HD. Serum magnesium was measured at start, after 2 hours, and at the end of the HD sessions. Total sMg concentration corrected for albumin was according to Krolles proposed formula. Blood pressure was measured every 30 min. Data were analyzed by SPSS.15. A P value of less than 0.05 was considered as significant. Occurrence of IDH among HD patients was 27.6% (16/58). Serum magnesium decreased significantly during HD session (P<0.05). Comparing corrected sMg in IDH group with non-IDH group showed that: corrected sMg was 0.66 ± 0.14 mmol/L vs. 0.84 ± 0.26 mmol/L at the start of dialysis (P=0.43), 0.62 ± 0.17 mmol/L vs. 0.74 ± 0.23 mmol/L (P=0.04) at 2 hours, and 0.61 ± 0.12 mmol/L vs. 0.72 ± 0.22 mmol/L (P=0.03) at the end of dialysis. Intradialytic hypotension episodes were significantly related to a decrease in sMg during dialysis (P=0.02). There was a significant decrease in sMg levels during dialysis. Intradialytic hypotension was significantly related to lowered sMg levels during dialysis.     

Multifamily Affordable Housing: Residential Satisfaction

The objectives of this paper are to identify strategic issues impacting multifamily affordable housing resident satisfaction and to develop a systematic model to forecast residential satisfaction based on data gathered from two multifamily affordable housing properties located in Atlanta. This study concluded that major variables impacting residence are satisfaction with property management, tenant selection policies, enforcing residential rules, communication with residents, property management staff answering quickly to residents’ concerns, how cooperative property management staff is with residents, how friendly staff is to residents, residents referring their friends to live in their apartment complex, quality of the community, maintenance, residents’ quality of life, building quality, quality of building repairs, overall cleanness of property grounds, overall cleanness of the community, residents’ perception of safeness in their neighborhood at night, residents’ perception of safeness at night while inside their units, and overall resident satisfaction with their apartment units. The study provides a framework for developing a decision support system that could be used by property managers or developers.     

Design and Construction Challenges of a Federal Laboratory Building: A Case Study

This paper presents a case study regarding design and construction challenges of a federal laboratory building. The case study illustrates the successful collaboration of two federal agencies, General Services Administration (GSA) and Centers for Disease Control and Prevention (CDC). Creative methods were used to resolve complex design, construction, and budgetary issues. This paper describes lessons learned from a specific laboratory project on issues such as: A master plan and its role in locating secure laboratory buildings, site planning issues, contracting mechanisms, building security, energy, project development, design and construction excellence, and funding. Although CDC and GSA approved the release of this paper, the authors offer a disclaimer that the opinions and conclusions drawn in the papers are those of the authors, and are not necessarily shared by the CDC and GSA.     

Effects of ultrasonic waves on carbon dioxide solubility in brine at different pressures and temperatures

The adverse impacts of CO₂ emission on the global warming highlight the importance of carbon capture and storage technology and geological storage of CO₂ under solubility trapping mechanisms. Enhancing the solubility of CO₂ in formation water has always been the focus of research in the area of CO₂ sequestration. Ultrasound techniques are one of the environmentally friendly methods that use high-intensity acoustic waves to improve gas solubility in liquids. Ultrasonic waves can alter the properties of different phases that lead to chemical reactions and provide a means to increase the solubility of CO₂ in connate water. In this study, we investigated the effects of ultrasound on the solubility of CO₂ in connate water under different conditions of pressure, temperature, and salinity. The results showed that the solubility of CO₂ was improved with increasing pressure under ultrasonic effects. However, the solubility of CO₂ was inversely proportional to the increase in brine salinity and temperature. Therefore, it was concluded that the solubility of CO₂ might be enhanced in the presence of ultrasound.     

Strategic policy analysis for infrastructure rehabilitation using system dynamics

Recent requirements for sustainable development and increasing trend for public–private partnerships (PPPs) have added additional complexities to the policy-making process in the infrastructure management domain. To support policy analysis, this paper presents a system dynamics (SD) model to analyse the impact of different strategic policies (e.g. budgeting, PPP involvement) on infrastructure serviceability, backlog accumulation and sustainability. The proposed model has been implemented on a network of school buildings from the Toronto District School Board asset inventory. Four sets of experiments with different policy scenarios over a 50-year strategic planning horizon have been conducted to investigate policies related to rehabilitation, budget distribution, government investment and PPP involvement. The proposed model was implemented on a commercial SD software incorporating all the dynamic interactions among the strategic parameters. The experiment results show that the model works as a practical decision support tool that enables asset managers to test the effectiveness of various strategic policy scenarios on long-term infrastructure performance.