On the Theoretical Carbon Storage and Carbon Sequestration Potential of Hempcrete

Hempcrete is a natural insulation material that is well known for exhibiting favorable thermal properties and low manufacturing emissions. Hempcrete is a biocomposite, consisting of hemp shiv and a lime-based binder composed of hydrated lime and either a hydraulic (e.g., natural hydraulic lime and ordinary portland cement) or pozzolanic binder (e.g., metakaolin). While long-term biogenic carbon storage can be achieved via utilization of hemp shiv in hempcrete, additional carbon storage can be achieved via carbonation of the binder. This study advances previous carbonation modeling approaches by deriving a theoretical model based on the fundamentals of cement hydration and carbonation chemistry to quantify the total theoretical in situ CO2e sequestration potential of hempcrete binders. To estimate the percentage of manufacturing CO2e emissions that can be recovered through in situ binder carbonation, the model is implemented in life cycle assessments of 36 hempcrete formulations of various binder contents and densities using an equivalent functional unit (FU) of a 1&nbsp;m2 wall assembly with a U-value of 0.27&nbsp;W/(m2K). Our model estimates between 18.5% and 38.4% of initial carbon emissions associated with binder production can be sequestered through in situ carbonation. Considering biogenic carbon storage, we predict that the total life cycle CO2e emissions of hempcrete can be negative, with a minimum of&nbsp;&minus;16.0&nbsp;kg CO2e/FU for the hempcrete mixture formulations considered herein. However, we estimate that some hempcrete formulations can exhibit net-positive emissions, especially high-density mixes (&gt;300&nbsp;kg/m3) containing portland cement, thereby illustrating the importance of materials selection and proportioning in designing carbon-storing hempcrete. &nbsp;</p

Wood in buildings: the right answer to the wrong question

Reducing the embodied emissions of materials for new construction and renovation of buildings is a key challenge for climate change mitigation around the world. However, as simply reducing emissions is not sufficient to meet the climate targets, using bio-based materials seems the only feasible choice as it permits carbon storage in buildings. Various studies have shown that bio-based materials allow turning overall life cycle impacts negative, therefore, having a cooling effect on the climate. In recent years, scholars and policy makers have focused almost exclusively on the advancement of wooden buildings. Timber structures stand out as they can be prefabricated and used for high-rise buildings. Yet, one important aspect seems to be overlooked: the consideration of supply and demand. Large forest areas that allow sustainable sourcing of woody biomass only exist in the Northern hemisphere, notably in North America and Europe. In these regions, though, urbanization rates are mostly stagnating, meaning new construction rates are low. The largest amount of material requirements in these regions are derived from the refurbishment of the existing stock. Moreover, in areas where structural material is needed for new construction, in Asia, Africa and South America, rain forests need to be protected. Therefore, we need to rethink the desire to find one solution and carelessly implement it everywhere. Instead, we need to consider locally available material and know-how for grounded material choices. This paper explores the supply of a range of bio-based materials and matches it against the material demand of global building stocks. It is based on various previous studies by the authors, of South Africa, China, Portugal, and more. The analysis divides between structural materials for new construction, such as wood and bamboo, and thermal insulation materials for the refurbishment of existing buildings, such as straw and hemp. The results emphasize the need for diversifying bio-based material solutions

High throughput mutagenesis for identification of residues regulating human prostacyclin (hIP) receptor

The human prostacyclin receptor (hIP receptor) is a seven-transmembrane G protein-coupled receptor (GPCR) that plays a critical role in vascular smooth muscle relaxation and platelet aggregation. hIP receptor dysfunction has been implicated in numerous cardiovascular abnormalities, including myocardial infarction, hypertension, thrombosis and atherosclerosis. Genomic sequencing has discovered several genetic variations in the PTGIR gene coding for hIP receptor, however, its structure-function relationship has not been sufficiently explored. Here we set out to investigate the applicability of high throughput random mutagenesis to study the structure-function relationship of hIP receptor. While chemical mutagenesis was not suitable to generate a mutagenesis library with sufficient coverage, our data demonstrate error-prone PCR (epPCR) mediated mutagenesis as a valuable method for the unbiased screening of residues regulating hIP receptor function and expression. Here we describe the generation and functional characterization of an epPCR derived mutagenesis library compromising >4000 mutants of the hIP receptor. We introduce next generation sequencing as a useful tool to validate the quality of mutagenesis libraries by providing information about the coverage, mutation rate and mutational bias. We identified 18 mutants of the hIP receptor that were expressed at the cell surface, but demonstrated impaired receptor function. A total of 38 non-synonymous mutations were identified within the coding region of the hIP receptor, mapping to 36 distinct residues, including several mutations previously reported to affect the signaling of the hIP receptor. Thus, our data demonstrates epPCR mediated random mutagenesis as a valuable and practical method to study the structurefunction relationship of GPCRs. © 2014 Bill et al

The effect of cochlear implantation on music perception by adults with usable pre-operative acoustic hearing

This study investigated the change in music perception of adults undergoing cochlear implantation. Nine adults scheduled for a cochlear implant (CI) were assessed on a music test battery both prior to implantation (whilst using hearing aids; HAs), and three months after activation of their CIs. The results were compared with data from a group of longer-term CI users and a group of HA-only users. The tests comprised assessments of rhythm, pitch, instrument, and melody perception. Pre-to-post surgery comparisons showed no significant difference in the rhythm, melody, and instrument identification scores. Subjects' scores were significantly lower post-implant for ranking pitch intervals of one octave and a quarter octave (p=0.007, and

Efficiently learning the preferences of people

Contains fulltext : 103332.pdf (author's version ) (Open Access