Potential of relative humidity as a proxy of air temperature in developing passive and adaptive building fa\ue7ades with bio-based responsive materials

There has been significant development in thermo-responsive materials for drug delivery and bio-medical use; some are bio-based. However, the use of thermo-responsive bio-based materials in the built environment, especially on the building fa\ue7ade, is almost non-existent due to complexities including difficulties manufacturing in bulk, cost and durability to weathering. On the other hand, humidity-responsive materials such as wood are abundant and are used in buildings globally. Furthermore, new bio-based humidity-responsive materials such as bacterial cellulose (BC) and natural fibres have the potential for building applications. In this study, we hypothesised that if there was a relationship between the relative humidity and air temperature in a location, humidity-responsive materials could be used to develop passive and adaptive building fa\ue7ades, which would indirectly respond to temperature. Here, we selected two sites (New Delhi, India and Newcastle upon Tyne, UK) with temperate climates — according to the K\uf6ppen-Geiger system— to analyse the relationship between relative humidity and air temperature from 37 years (1985-2022) of weather data and typical meteorological year (TMY) climate data for 2004-2018. This relationship assessment used the Pearson correlation (coefficient and p-value) analysis. Our results showed a strong and statistically significant negative correlation between the relative humidity and air temperature in all months in 37 years in New Delhi, with the strongest correlation in the summer and monsoon months. However, the correlation was strong only in some summer months for Newcastle upon Tyne. We concluded that humidity-responsive bio-based materials have the potential to be used to actuate passive and adaptive building fa\ue7ades in New Delhi (for all-year-round use) and Newcastle (only during summer), which respond indirectly to external temperature

Bio-jaali: Passive building skin with mycelium for climate change adaptation to extreme heat

Climate change induced global warming and frequent extreme heat events have become common recently, increasing the ownership and operation of active cooling, particularly in cities and megacities. To reduce the dependency on active cooling, in this study, we aimed to re-design ‘Jaali’— perforated screens made of bricks and sandstones to cool the incoming air inspired by historical building use— with bio-based materials such as mycelium. We hypothesised that ‘Bio-jaali’ would ventilate and reduce the indoor temperature reducing energy demand for cooling. For the climatic context, we selected the temperate climate of New Delhi. We used climatic data analysis and performance-based dynamic environmental simulations with Designbuilder and Energy Plus to evaluate the effect of Bio-jaali on the indoor operative temperature in a single-zone naturally ventilated indoor office space. The simulation results showed sandstone Jaali reduced the annual average indoor operative temperature by 5.2%, whereas Bio-jaali were able to provide a reduction of 3.0% compared to the base case. Furthermore, the seasonal analysis showed that Bio-jaali reduced the summer indoor operating temperature by decreasing heat gain from outdoor heat, particularly during daytime and increased indoor temperature during winter by reducing heat loss, demonstrating its potential for year-round usage

Bacterial Cellulose as a Building Material: Identifying opportunities, limitations and challenges

Bacterial cellulose (BC), a bacteria-synthesised cellulose material, has been intensively researched in biomedical, food and packaging over several decades. However, its application in the built environment (BE) has received less attention. This paper scopes out BC’s original properties and the methods used to modify them. This capability to modify the properties of BC offers exciting possibilities for creating building components with low environmental impact, enhanced properties and targeted performance. In its unprocessed hydrogel state, BC yields promising strength and durability. This biodegradable material\u27s production process can be sustained by several waste streams, making it a promising material for the circular economy. When used in composites, BC can act as a scaffold for multiple nanoparticles and polymers, extending its properties to, for example, provide electrical conductivity or antimicrobial surfaces. However, to support BC’s application in the BE, the material must be studied at multiple scales, namely nano-, micro- and macro-scale. Standardised tests need to be developed and tailored to measure BC behaviour under complex BE scenarios. Its interaction with humidity, durability and its regenerative properties are identified as potentially fruitful areas for further investigation

The Use of Preoperative Epoetin-α in Revision Hip Arthroplasty

PURPOSE: To evaluate the efficacy of preoperative epoetin-α on the revision hip arthroplasty patient. We hypothesized that epoetin-α will reduce blood transfusion. A pertinent review of the literature is provided. METHODS: Forty-six patients were retrospectively reviewed. Sixteen patients received epoetin-α. Patients were case matched by age, preoperative hemoglobin, surgery, gender, and BMI. The clinical triggers for blood transfusion during or after the procedure were determined based on peri- and postoperative hemoglobin levels, ASA score, and/or clinical symptoms consistent with anemia. Blood salvage was not used. RESULTS: Blood transfusion and length of stay were decreased in the epoetin-α group. Hemoglobin in the intervention group increased from 12.0 to 14.5, preoperatively. Patients who received epoetin-α were 0.78 (RR=0.225) times as likely to receive a transfusion. Number Needed to Treat (NNT) to avoid one allogeneic transfusion was 1.84. Age, Gender, BMI, ASA, total and hidden blood loss, preoperative Iron supplements, preop Hct, preop PLT, PT, PTT, and INR were similar. One (6.0%) patient developed an uncomplicated deep venous thrombosis in the intervention group. CONCLUSIONS: The mildly anemic revision hip arthroplasty patient is at increased risk for transfusion. Epoetin-α increased preoperative hemoglobin counts and reduced transfusions in this study; it also decreased patient length of hospital stay likely allowing for an earlier readiness to resume normal activities and/or meet short-term milestones. A randomized study to evaluate the direct and indirect costs of such a treatment methodology in the mildly anemic revision patient may be warranted