The effects of air permeability, background ventilation and lifestyle on energy performance, indoor air quality and risk of condensation in domestic buildings

Effective and efficient ventilation is essential when improving energy performance and Indoor Air Quality (IAQ) of buildings. Reducing air permeability can considerably improve the energy performance of buildings; however, making the buildings more airtight may result in lower rates of natural ventilation which may in turn increase the risks of condensation and unacceptable IAQ. This study evaluates the effects of different air permeability rates, background ventilation and occupants’ lifestyles on the energy performance as well as the risk of condensation and CO2 concentration in domestic buildings. Dynamic computer simulations were conducted in EnergyPlus. Results indicated direct relations between the ventilation rates, energy performance and IAQ. Higher air permeability along with background ventilation resulted in considerably better IAQ while energy consumption increased by up to four times. Occupants’ lifestyles were identified as a major contributor to the risk of condensation.This is the final version. It was first published by MDPI at http://www.mdpi.com/2071-1050/7/4/4022

A reinforcement learning model to inform optimal decision paths for HIV elimination

The \u27Ending the HIV Epidemic (EHE)\u27 national plan aims to reduce annual HIV incidence in the United States from 38,000 in 2015 to 9300 by 2025 and 3300 by 2030. Diagnosis and treatment are two most effective interventions, and thus, identifying corresponding optimal combinations of testing and retention-in-care rates would help inform implementation of relevant programs. Considering the dynamic and stochastic complexity of the disease and the time dynamics of decision-making, solving for optimal combinations using commonly used methods of parametric optimization or exhaustive evaluation of pre-selected options are infeasible. Reinforcement learning (RL), an artificial intelligence method, is ideal; however, training RL algorithms and ensuring convergence to optimality are computationally challenging for large-scale stochastic problems. We evaluate its feasibility in the context of the EHE goal. We trained an RL algorithm to identify a \u27sequence\u27 of combinations of HIV-testing and retention-in-care rates at 5-year intervals over 2015-2070 that optimally leads towards HIV elimination. We defined optimality as a sequence that maximizes quality-adjusted-life-years lived and minimizes HIV-testing and care-and-treatment costs. We show that solving for testing and retention-in-care rates through appropriate reformulation using proxy decision-metrics overcomes the computational challenges of RL. We used a stochastic agent-based simulation to train the RL algorithm. As there is variability in support-programs needed to address barriers to care-access, we evaluated the sensitivity of optimal decisions to three cost-functions. The model suggests to scale-up retention-in-care programs to achieve and maintain high annual retention-rates while initiating with a high testing-frequency but relaxing it over a 10-year period as incidence decreases. Results were mainly robust to the uncertainty in costs. However, testing and retention-in-care alone did not achieve the 2030 EHE targets, suggesting the need for additional interventions. The results from the model demonstrated convergence. RL is suitable for evaluating phased public health decisions for infectious disease control

Assessing the Risks of Dampness and Mould Growth in Renovated Properties

A large portion of the UK housing stock was built before the introduction of the 1989’s building regulations in which insulated cavity walls became mandatory. It is estimated that 65% of the UK housing stock have uninsulated walls and 49% have single glazed leaky windows making them inefficient in terms of energy performance. There have been great efforts during the recent years to improve the quality and energy performance of such buildings through retrofitting/refurbishment not only to improve the living standards of their occupants but also to achieve UK’s carbon emission targets for 2050. Refurbishing such buildings to improve their quality/energy performance may, at the same time, increase the risk of poor indoor air quality (IAQ), condensation, dampness, and mould growth in these buildings. Many refurbished housing stock in the UK are facing similar problems. Damp and mould issues affect between 30-50% of new or refurbished buildings. There is therefore a need for appropriate design strategies not only to improve the quality and thermal performances of such buildings but also to reduce the aforementioned risks through better design, construction detailing, methods, and management processes. This paper reports on the first phase of a joint university/industry Knowledge Transfer project to address the above issues in renovated student accommodations in North West England. Temperature, relative humidity, CO2, and meter readings are measured and recorded in three case study buildings. Results revealed a direct relationship between energy consumption, IAQ, and occupants’ behaviours in the buildings. CO2, Temperature, and RH levels were more acceptable in one of the case study buildings; however, its energy consumption was 7 times higher when compared with a similar building

Effects of Manual and Automatic Natural Ventilation Control Strategies on Thermal Comfort, Indoor Air Quality and Energy Consumption

Occupants of naturally ventilated buildings can tolerate wider ranges of temperature and Indoor Air Quality (IAQ) if they have more control over their environment. Meanwhile, due to the complexity of advanced natural ventilation (ANV) strategies, introducing some form of automatic control is essential despite the fact that they limit the occupants’ control over their environment. Therefore, it is essential to understand the performance of ANV systems and occupants’ behaviours in order to identify a balance between automatic and manual controls to enhance the performance of ANV systems while maintaining the occupants’ comfort. The aim of the work reported in this paper is to evaluate the effects of a retrofitted ANV system with manual and automatic controls on thermal comfort, indoor air quality and energy consumption in an open-plan office building in the UK. Physical measurements were used to study the building performance in terms of thermal comfort, IAQ and energy consumption. The results revealed that occupants were much more aware about thermal comfort compared to IAQ. Therefore, relying on the occupants to control the ventilation system would considerably increase the risk of poor IAQ in buildings. Moreover, introducing automatic controls did not affect the thermal comfort conditions for those who understood and actively controlled the ANV system, while the situation improved for those occupants who were not active. Results of this study showed that introducing automated natural ventilation helped to reduce energy consumption by 8%

Purification and characterization of &#945-galactosidase from Lactobacillus acidofillus

α−Galactosidase (α-D-galactoside galactohydrolase [EC 3.2.1.22]) was obtained from Lactobacillus acidofillus which was grown in modified de Man, Rogosa and Sharpe (MRS) medium, supplemented with raffinose. α-Galactosidase was released from the cells by ultrasonic treatment, then precipitated by ammonium-sulfate and further purified with Sephadex G-200 and DEAE cellulose chromatography with a 18.5-fold increase in specific activity and 28% recovery. Km and Vmax for this enzyme was determined by p-nitrophenyl-α-D-galactoside as substrate, to be about 0.47 mM, and 17.54 μmol/min per mg of protein, respectively. Maximum enzymatic activity occurred at pH 5.5 and temperature at 45°C. The enzymatic activity was retained at least for 30 min, at temperatures of 25 - 55°C, but there was inactive temperature at about 60°C. Galactose was able to decrease the enzyme activity by a factor of 63%. Among the sugars tested, fructose, glucose, sucrose, lactose and mannose reduced the enzyme activity only slightly (less than 10% of the control). A strong inhibition of α-galactosidase activity was found in the presence of 0.1 mM HgCl.Key words: α-Galactosidase, enzyme purification, Lactobacillus acidofillus, kinetic studies

Analisis Kinerja Keuangan Perusahaan Sebelum Dan Sesudah Initial Public Offering (Ipo) Di Bursa Efek Indonesia (Studi Pada Perusahaan Non Finansial Yang Listing Di Bei Tahun 2011)

The purpose of this study is to explain the differences in financial performance of non-financial companies before and after the Initial Public Offering (IPO) at the Indonesia Stock Exchange (BEI). This study uses a quantitative approach with statistical methods. The research variables consisted of Current Ratio (CR), Debt to Equity Ratio (DER), Debt Ratio (DR), Total Assets Turnover Ratio (TATO), Net Profit Margin (NPM), Return on Investment (ROI) and Return on Equity (ROE). Data analysis is descriptive statistical analysis and inferential statistical analysis consisting of normality test and test hypotheses using SPSS version 20. The results of testing the hypothesis by using paired sample t-test showed that there were significant differences in the company's financial performance before and after the IPO when viewed from the mean CR and ROE. Meanwhile, if viewed from the mean DER, DR, TATO, NPM, and ROI, there are no significant differences in the company's financial performance before and after the IPO. When viewed as a whole, the company's financial performance was not increased after an IPO. This can happen due to a short observation period and also the condition that the company is still in the adjustment phase after an IPO

The modalities of Iranian soft power: from cultural diplomacy to soft war

Through exploring Iran's public diplomacy at the international level, this article demonstrates how the Islamic Republic's motives should not only be contextualised within the oft-sensationalised, material or ‘hard’ aspects of its foreign policy, but also within the desire to project its cultural reach through ‘softer’ means. Iran's utilisation of culturally defined foreign policy objectives and actions demonstrates its understanding of soft power's potentialities. This article explores the ways in which Iran's public diplomacy is used to promote its soft power and craft its, at times, shifting image on the world stage

Evaluation of ultrasound technology to break seed dormancy of common lambsquarters (Chenopodium album)

Although seed dormancy is advantageous for annual plants in the wild, unsynchronized germination in the laboratory leads to increased error in measurements. Therefore techniques to promote and synchronize germination are routinely used. Ultrasound is one of the newest methods for breaking dormancy in weed seeds. We have investigated whether ultrasonic waves can be used to break seed dormancy of common lambsquarters (Chenopodium album), a highly competitive annual weed that leads to significant reduction of yields of corn, soybeans, and sugar beets. Ultrasonic waves with frequency of 35kH were applied for 0 (control), 5, 10, 15 and 30 minutes using a completely randomized design. The results showed that the use of ultrasound waves generally enhanced the traits under investigation in the treated samples compared to the control sample. The maximum enhancement of germination percentage (180%), seedling dry weight (78%), and seedling vigor index I (271%) and II (392%) was seen in the common lambsquarters samples treated with ultrasound for 15 minutes and seedling length (40%) at 30 minutes compared to the control samples. Radical lengths were not statistically different from controls under any treatment and plumule length only increased marginally. These changes are reflected in seedling vigor index I and II measurements. For some of these traits, increasing the length of ultrasound treatment to 30 minutes had negative effects. These results demonstrate that ultrasound technology can be used as a quick, and efficient non-destructive method to break seed dormancy in common lambsquarters

Control of Carbon Dioxide Concentration in Educational Spaces Using Natural Ventilation

This article was accepted for publication in the International Journal of Ventilation [© VEETECH]. The definitive version is available from: http://www.ijovent.org.uk/This paper reports on research carried out to develop natural ventilation control strategies for densely occupied learning spaces with the intention of improving indoor air quality and heating energy consumption. Investigations were carried out for two test cases according to the characteristics given in CIBSE Guide A (2006) and Building Bulletin (BB) 101 (Department for Education, 2006). The performance of these test cases were assessed using dynamic thermal simulation with fixed CO2 set-points, based on which opening dampers are controlled. Improvements to the control strategy are then proposed. The results show that acceptable indoor air quality can be achieved in almost all cases by adopting typical, traditional control strategies. However, energy consumption can be reduced further by applying more advanced control strategies which use two CO2 set-points to regulate the opening sizes in a non-linear, but stepwise manner. Simulation results predict savings in heating energy consumption of at least 30%