Materials design for sustainability through life cycle modeling of engineered cementitious composites

Evaluating and enhancing construction material sustainability requires a life cycle perspective of the structures in which they are used, since material properties and durability can have a profound effect on overall infrastructure performance. A framework is proposed to evaluate and enhance the design of “greener” materials that integrates material design, structural design, and life cycle modeling of the built system. This framework is applied to engineered cementitious composite materials, a family of high performance fiber-reinforced composites used as link slabs in a concrete bridge deck. Modeling results show incorporating waste materials, such as fly ash, should be pursued only if the material retains adequate durability for the structural application where it is used. Additionally, traffic congestion resulting from bridge deck construction and rehabilitation events dominates environmental and economic life cycle results, consuming the most energy, producing the largest amount of pollutants, and generating the greatest life cycle costs.     

Stress assessment based on Ergonomics coupled with image-processing tools and techniques for lean product design and development

This paper presents an innovative lean ergonomic tool (LET) for mental stress through facial muscle activity assessment. An image-processing tool has been developed based on the analysis of facial angles. These angles were perceived by analyzing the stress levels of product development team members at certain conditions. A total number of 26 subjects participated in the experiments. On the basis of angular deviation levels, a stress level classification scheme was developed using neutral position of each team members for each task. Through statistical analysis, team members were divided into the groups of same degree of stress level. Each group was assigned a numerical expression value which was relative to the perceived stress level of that group for each task. Using five distinct action categories, a criterion for the evaluation of stress level was proposed which was validated through two distinct case studies. The developed LET will help the top management in taking corrective actions to reduce the stress level during product design and development.     

Measures for sustainability

Clean Technologies and Environmental Policy -     

Emerging technologies for enabling proangiogenic therapy

Ischemic disease causes a large number of deaths and significant clinical problems worldwide. Therapeutic angiogenesis, strengthened by advances in growth-factor-based therapies, is a promising solution to ischemic pathologies. Major challenges in therapeutic angiogenesis are the lack of stability of native angiogenic proteins and also providing sustained delivery of biologically active proteins at the ischemic sites. This paper will discuss various protein engineering strategies to develop stabilized proangiogenic proteins and several biomaterial technologies used to amplify the angiogenic outcome by delivering biologically active growth factors in a sustained manner.     

Enhancement of seismic sustainability of critical facilities through system analysis

Proper functioning of critical facilities such as acute care hospitals and fire stations are essential in the aftermath of a severe earthquake. For these facilities to remain operational, not only their building structures must remain safe for continued occupancy, but also their nonstructural components/systems must remain functional. Motivated by a previous study by the second author, this paper demonstrates a probabilistic system analysis for enhancing the sustainability of deficient critical facilities. The analysis, in principle, utilizes event and fault tree procedures to evaluate the system fragility defined by the probability that the system will not perform its intended purpose. Enhancement of sustainability is demonstrated by using a representative numerical model of an existing facility. The study shows that by selecting the most vulnerable components, utilizing the concept of annual sensitivity index, the annual probability of failure can be reduced significantly in a cost-effective way.     

Development of a fast,lean and agile direct pelletization process using experimental design techniques

A novel hot melt direct pelletization method was developed, characterized and optimized, using statistical thinking and experimental design tools. Mixtures of carnauba wax (CW) and HPMC K100M were spheronized using melted gelucire 50–13 as a binding material (BM). Experimentation was performed sequentially; a fractional factorial design was set up initially to screen the factors affecting the process, namely spray rate, quantity of BM, rotor speed, type of rotor disk, lubricant–glidant presence, additional spheronization time, powder feeding rate and quantity. From the eight factors assessed, three were further studied during process optimization (spray rate, quantity of BM and powder feeding rate), at different ratios of the solid mixture of CW and HPMC K100M. The study demonstrated that the novel hot melt process is fast, efficient, reproducible and predictable. Therefore, it can be adopted in a lean and agile manufacturing setting for the production of flexible pellet dosage forms with various release rates easily customized between immediate and modified delivery.     

Lithography for enabling advances in integrated circuits and devices

Because the transistor was fabricated in volume, lithography has enabled the increase in density of devices and integrated circuits. With the invention of the integrated circuit, lithography enabled the integration of higher densities of field-effect transistors through evolutionary applications of optical lithography. In 1994, the semiconductor industry determined that continuing the increase in density transistors was increasingly difficult and required coordinated development of lithography and process capabilities. It established the US National Technology Roadmap for Semiconductors and this was expanded in 1999 to the International Technology Roadmap for Semiconductors to align multiple industries to provide the complex capabilities to continue increasing the density of integrated circuits to nanometre scales. Since the 1960s, lithography has become increasingly complex with the evolution from contact printers, to steppers, pattern reduction technology at i-line, 248 nm and 193 nm wavelengths, which required dramatic improvements of mask-making technology, photolithography printing and alignment capabilities and photoresist capabilities. At the same time, pattern transfer has evolved from wet etching of features, to plasma etch and more complex etching capabilities to fabricate features that are currently 32 nm in high-volume production. To continue increasing the density of devices and interconnects, new pattern transfer technologies will be needed with options for the future including extreme ultraviolet lithography, imprint technology and directed self-assembly. While complementary metal oxide semiconductors will continue to be extended for many years, these advanced pattern transfer technologies may enable development of novel memory and logic technologies based on different physical phenomena in the future to enhance and extend information processing.     

Education for sustainability: challenges and trends

There has been increasing recognition of the critical role of education for sustainability (ES). This article addresses the subject of ES through all the levels of formal and non-formal education, including basic education, university, organisations (private and public) and lifelong learning. The challenges and implications of effectively incorporating sustainability concepts and principles through all the levels of the education system are presented and analysed. Examples and suggestions are presented and discussed, taking into account the interactions, needs and objectives of people and society.

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Metrics for supply chain sustainability

Most interpretations of sustainable development recognise that there are constraints on long-term human activities imposed by material and energy availability and by the capacity of the planet to accommodate wastes and emissions; inter- and intra-generational equity within these constraints is then an ethical principle underlying sustainability. This leads to identifying three dimensions of sustainable development: techno-economic, ecological and social. This paper reviews the development of indicators to reflect these three dimensions, applicable to industrial sectors, companies and broad groups of products or services. Indicators of environmental and economic performance are relatively well established. They can be combined to indicate the sustainability of products, services and supply chains. Indicators of social performance are more problematic, particularly indicators to describe the social value of products and services. Cases from the process, petroleum and petrochemicals, electronics and fast moving consumer goods sectors are reviewed, showing that social indicators must be developed through public participation.     

Synthesis of ferroelectric perovskites through aqueous-solution techniques

The hydrolysis of niobates in aqueous solutions has been applied to the coprecipitation of PbNb_2/3Mg_1/3O₃ leading to a low temperature synthesis of this ferroelectric relaxor ceramic. The effect of hydrolysis conditions — such as the concentration of bases and acids used, their rates of addition and the nature of the precursors salts — is described. The perovskite phase appears after heating at 350C and is obtained as a pure phase at 800C after heat treatment for 1 h. Relaxor ferroelectric ceramics with a high dielectric constant can be obtained by sintering at 1000C. The process has been also applied to the synthesis of other relaxor ceramic compositions such as PZN (PbNb_2/3Zn_1/3O₃) and PFN (PbNb_1/2Fe_1/2O₃) compounds.     

Wave propagation through engineering materials; assessment and monitoring of structures through non-destructive techniques

Elastic wave propagation has been used for decades for assessment of the structural integrity of engineering materials. The advantage it offers is the direct connection to elastic properties, the relatively easy application through commercial equipment as well as numerous empirical correlations between pulse velocity and material strength or quality in general. Advanced features like frequency dependence of wave parameters may further improve the characterization capacity. Concrete materials due to their inherent microstructure, which is enhanced by the existence of damage-induced cracking, exhibit a complicated behavior concerning the propagation of pulses of different frequencies. The different wave lengths interact with inhomogeneities according to their size and therefore, leave their signature on the phase velocity and attenuation versus frequency curves. Although experimental measurements are troublesome in concrete structures, mainly due to attenuation of high frequencies, it is suggested that, whenever possible, application of different frequencies can provide a more detailed insight on the internal condition of the structure. Apart from classical elastic wave studies, the scattering microstructure of concrete exercises strong influence on the elastic signals emitted after cracking events, distorting therefore crucial acoustic emission parameters used for the characterization of the structural integrity. In the present paper experimental evidence of dispersion and examples on how it can be utilized in concrete non destructive inspection are presented and discussed.     

Urban regeneration and impact assessment for social sustainability

This paper provides a working definition of social sustainability and highlights the growing array of social sustainability assessment tools (e.g. SIA, HIA, equality impact assessment, SA). Within EIA the social dimension has been very much the ‘poor relation’. However, changes in the UK planning system, the drive for sustainable communities, and for greater public involvement in decision making are raising the profile of the social dimension. This is particularly relevant for urban regeneration projects, which are often mixed use (including housing), and with the potential for development to be shaped by community involvement. The paper includes a review of recent environmental statements (ESs) for regeneration projects in the UK, which provides findings on, for example, the inclusion of social factors in the process; scope of such factors; methodological approaches and impact assessment tools; and role of community involvement. The research raises questions about the extent to which social issues shape outcomes; it also highlights some important challenges, including the key issue of ‘integration versus disintegration’ in the scope and process of impact assessment.     

Integrated sustainability assessment for chemical processes

Policies on sustainable development have resulted in the wide concern about economic, safety, and environmental-friendly chemical production. This work focuses on the development of a holistic methodology that enables the evaluation and comparison of process sustainability in an integrated system. This methodology is proposed based on material and energy flows, process parameters, and process configuration. It uses a set of criteria, including inherent safety, potential environmental impact, and economic aspects. These criteria as the basis for determining the integrated index can be used to perform sustainability assessment for process alternatives under investigation. The multi-criteria decision analysis procedure is presented to conduct the integrated assessment based on qualitative and quantitative analysis. As a case study, ethanol production process, i.e., ethylene-derived feedstock process (A1) and straw cellulose-derived feedstock process (A2) are used to illustrate the proposed methodology. Results showed that A1 had advantage over A2 for the economic aspect while A2 had better performance in the environmental and safety aspects. A2 is the prior option from the point of view of comprehensive evaluation.     

Nanosized bismuth ferrite powder prepared through sonochemical and microemulsion techniques

Two processing routes, namely sonochemical and microemulsion have been exploited to prepare bismuth ferrite powders. Phase pure nanosized BiFeO₃ powders are prepared by sonochemical and microemulsion techniques in the temperature range of 400 °C and at 500 °C which is much lower than that of the conventional preparation methods. The XRD obtained from both cases was likely to be pure bismuth ferrite. Though the microemulsion based powders showed slightly better properties with respect to particle size, surface area, and final density, sonochemically prepared powders may be more acceptable considering the ease of preparation and cost effectiveness.