Using Thermal Inertia of Buildings with Phase Change Materials as a Flexible Energy Resource

The massive uptake of distributed energy resources (DERs) and advancement in infrastructure technologies have attracted more attention on demand response. Using photovoltaic (PV) systems and battery storage systems enable end-users to actively manage their energy consumption by shifting or reducing flexible loads. One of the flexible loads that contribute primarily to buildings’ energy usage and overall energy consumption worldwide is space heating and cooling. In recent years, the thermal inertia of a building has been demonstrated as a potential alternative to battery energy storage. In some countries such as Australia, the predominant type of building has low thermal inertia. Therefore, using thermal inertia as an alternative to battery storage systems becomes infeasible for these lightweight buildings. However, the integration of phase change materials (PCMs) into the building’s envelope improves the building’s thermal inertia significantly. The present dissertation expands frontiers of PCM application in residential buildings, offering advances on PCM integration into home energy management systems (HEMS) that can be installed in smart meters with low computational power. Moreover, through many case studies in Australia, it investigates the viability of PCM to use as an alternative to the battery storage system to reduce electricity cost and increase self-consumption of PV systems

Acute Poisoning With Peganum Harmala, Esfand: A Rare Case Report

Peganum harmala, is a plant of the family Nitrariaceae with small seeds, traditionally used to induce abortion and menstruation. It also has pharmacological properties such as lowering blood glucose, as well as analgesic, anti-cancer, antibacterial and antifungal effects. The current report presents a rare case of a middle-aged female referring to Clinical Toxicology Service with the history of drinking a glass of boiled Esfand seeds, in order to reduce blood sugar, and complaining of nausea, abdominal pain, general weakness, dizziness, and several vomiting episodes.

using thermal inertia of buildings with phase change material for demand response

Abstract: In recent years, demand response programs have proved useful in managing peak demand and meeting sustainability goals, enabling an efficient use of the smart grid. Heating, ventilation, and air conditioning (HVAC) loads in buildings constitute a large proportion of the total energy consumption of households, and accordingly, a flexible and efficient operation of these devices can aid power utilities in meeting load management objectives while reducing consumer's electricity bills. With the emergence of promising new technologies, such as phase change materials (PCM), buildings can serve as a virtual thermal energy storage, which improves energy efficiency and also allows occupants to offer grid services like peak demand reduction. The objective of this paper is to establish the effectiveness of PCM as a demand response resource, demonstrating the extent to which it can be used for peak demand reduction. A wide range of scenarios are considered to investigate the impacts of geographical location, PCM melting point, duration of precooling and preheating, setting points of HVAC system, thickness and location of PCM, on the capability of the PCM in reducing or shifting the cooling and heating load. All simulations are performed using the EnergyPlus platform, examining typical residential buildings in five Australian cities: Brisbane, Sydney, Melbourne, Hobart and Perth. The simulation results showed a decrease in the HVAC demand in the buildings with PCM, in all cities, with the highest reductions observed in Hobart and Melbourne. The integration of a 20mm thick PCM in the roof, wall and floor of the building yielded a 21.8% and 16.7% reduction in annual HVAC demand in Hobart and Melbourne respectively, when compared to the building without PCM. However, this is with the assumption that the HVAC system is operating 24 hours a day for a whole year. The PCM-integrated building showed a shift in the HVAC demand in all cities except Perth. A shift by 9 minutes, 3 minutes, 60 minutes and 103 minutes was recorded in the cities of Brisbane, Sydney, Melbourne and Hobart respectively. The simulation results will be used in subsequent research to schedule the HVAC demand using a home energy management system

A study on job postures and musculoskeletal illnesses in dentists

Objectives: Musculoskeletal disorders (MSDs) compose a large part of occupational diseases in dental professionals, prevention of which is dependent on assessment and improvement of job postures by means of ergonomic interventions. This study was aimed at evaluation of ergonomic conditions of the profession of dentists and also at assessing the relationship between MSDs and conditions of work. Materials and Methods: This cross-sectional study was performed among 65 dentists using the method of Rapid Entire Body Assessment (REBA). The prevalence of MSDs was obtained by the use of the Nordic Musculoskeletal Questionnaire (NMQ). Results: In this investigation, the prevalence of MSDs for different body parts was: 75.9% for the neck, 58.6% for the shoulders, 56.9% for the upper back, 48.3% for the lower back and 44.8% for the wrist. Job analysis by the use of REBA showed that 89.6% of limbs in group A and 79.3% of limbs in group B had a score > 4. Only neck and lower back pain have significant relationship with the risk levels obtained using the REBA method. Conclusions: It can be concluded that work postures of dentists need to be improved. In addition to education, work station design, rest period during work and regular physical activities should be taken into account

Numerical Investigation of the Strain Stiffening Behavior of Mesenchymal Stem Cells on Elastic Substrates

In order to accurately predict the cellular response, it is necessary, along with other factors, to consider the effect of the cell spreading on the substrate. Also, the core tensions, due to the cell spreading, play a crucial role in the fate of a stem cell. Therefore, the exact prediction of these tensions is of particular importance. The effect of the strain stiffening of a mesenchymal cell, in a two-dimensional model, was investigated numerically using finite element method, by exerting a time function displacement, to the cytoplasm boundary. Utilizing Schwartz-Christoffel transformation, a model for cell-spreading was proposed that can be used to achieve accurate cellular responses. Three different models are considered. In the first model, the cell is treated as a non-alive material. That is, the mechanical properties remain constant on the substrate. Two other models, the linear and exponential strain-stiffening, are active models. By comparing the results of these models with the experimental results, it was found that the assumption that the cell is inactive departs the response from the exact amount. Therefore, considering the cell’s living nature, in both linear and exponential models, leads to more similarity of the results, both the tension value and the slope of the variations, with the experimental observations. Furthermore, by increasing the amount of the cell spreading, the difference in the amount of the nucleus stress in active models with the inactive model increases, so that the predicted tension by the linear model reaches 2.3 times that predicted by the non-alive model

Energy management of buildings with phase change materials based on dynamic programming

The thermal inertia of buildings is a flexible resource that can be used for shaping the space heating and cooling demand. However, in some countries, especially Australia, a large number of buildings have low thermal inertia. Given this context, this paper builds on the literature introducing phase change materials (PCM) to improve buildings' thermal inertia. Our main focus is to address the challenges of energy management in buildings with PCM. The corresponding optimisation problem involves scheduling an HVAC system while considering the PCM layer as an energy storage system. Solving this problem requires a technique that can deal with the nonlinear nonconvex characteristic of the PCM. We use dynamic programming (DP), which suffers from the curse of dimensionality. Given this drawback, we present preliminary work on developing computationally efficient DP methods for energy management with PCMs. We demonstrate that the proposed method produces high-quality solutions and yields considerable cost savings

A study on job postures and musculoskeletal illnesses in dentists

Objectives: Musculoskeletal disorders (MSDs) compose a large part of occupational diseases in dental professionals, prevention of which is dependent on assessment and improvement of job postures by means of ergonomic interventions. This study was aimed at evaluation of ergonomic conditions of the profession of dentists and also at assessing the relationship between MSDs and conditions of work. Materials and Methods: This cross-sectional study was performed among 65 dentists using the method of Rapid Entire Body Assessment (REBA). The prevalence of MSDs was obtained by the use of the Nordic Musculoskeletal Questionnaire (NMQ). Results: In this investigation, the prevalence of MSDs for different body parts was: 75.9% for the neck, 58.6% for the shoulders, 56.9% for the upper back, 48.3% for the lower back and 44.8% for the wrist. Job analysis by the use of REBA showed that 89.6% of limbs in group A and 79.3% of limbs in group B had a score > 4. Only neck and lower back pain have significant relationship with the risk levels obtained using the REBA method. Conclusions: It can be concluded that work postures of dentists need to be improved. In addition to education, work station design, rest period during work and regular physical activities should be taken into account