Quasi steady state and dynamic hygrothermal performance of fibrous Hemp and Stone Wool insulations: Two innovative laboratory based investigations

Moisture and heat management properties of Hemp and Stone Wool insulations were studied by mounting them between a hot and a cold climate chamber. Both insulations were exposed to identical hygrothermal boundary conditions. Quasi steady state and dynamic tests were carried out at a range of relative humidity exposures. The likelihood of interstitial condensation was assessed and equivalent thermal conductivity values of the insulations were determined. The adsorption-desorption isotherms of the insulations were also determined in a dynamic vapour sorption (DVS) instrument. It was observed that the likelihood of condensation was higher in Stone Wool insulation than in Hemp insulation. Hemp insulation performed better in managing moisture due to its high hygric inertia and water absorption capacity. It was observed that the equivalent thermal conductivity of Stone Wool insulation was dependent on enthalpy flow and phase change of moisture. The equivalent thermal conductivity of Hemp insulation was close to its declared thermal conductivity in dynamic conditions when high relative humidity exposures were transient. In quasi steady state boundary conditions, when the insulation was allowed to reach the equilibrium moisture content at ranges of relative humidity, there was a moisture dependent increase of thermal conductivity in Hemp insulation

Hygrothermal response of a dwelling house. Thermal comfort criteria

The use of local natural materials in order to reduce the environmental negative impact of buildings has become common practice in recent years; such buildings are to be found in all regions of the planet. The high level of thermal protection provided by the envelope elements made from natural materials such as straw bale insulation, hemp insulation or sheep wool, and their lack of thermal massiveness require a more complex analysis on their ability to keep interior comfort without accentuated variations. This paper proposes a comparative analysis between different solutions for a residential building located near a Romanian city, Cluj-Napoca. The elements of the building envelope are designed in three alternative solutions, using as substitute to classical solutions (concrete and polystyrene, masonry and polystyrene), straw bales and rammed earth for enclosing elements. For this purpose there are conducted numerical simulations of heat and mass transfer, using a mathematical model that allows the analysis of indoor comfort, by comparing both objective factors (air temperature, operative temperature and relative humidity) and subjective factors, which are needed to define interior thermal comfort indices PPD and PMV. Finally, a set of conclusions are presented and future research directions are drawn

Effect of Exposure to Environmental Cycling on the Thermal Conductivity of Expanded Polystyrene

The global effort to reduce energy consumption generated by buildings involves the increasing use of thermal insulation materials, with expanded polystyrene representing one of the most used materials to this end. The thermal performance of expanded polystyrene has been extensively studied; however, information on the effect of exposure to cyclic environmental conditions on its thermal performance is limited. Therefore, we conducted such a study, which is presented in this article. In the first stage, samples were subjected to 28 days of preconditioning to accelerate the increase in moisture in the material. The second stage involved exposure to 40 freeze–thaw cycles of 12 h each. The weight and thermal conductivity of the samples were measured before and after exposure, and the compression behavior was also analyzed. The results show a decrease in the thermal performance of expanded polystyrene exposed to cyclic environmental conditions, as demonstrated by an increase in the water content of the material under the same measurement conditions and an increase of 5.06% in the average thermal conductivity. The influence of this increase on the thermal performance of commonly used wall construction elements was also been studied and presented in this article. A decrease of 7.59% in the compressive stress of the material at 10% strain was also demonstrated

Microbiology of Dental Disease in Pet Rabbits

Maintenance of oral health and hygiene represents an essential condition in avoiding dental disease for humankind but also for the animal kingdom. This study aimed to present the importance of prevention techniques and treatment options for dental disease in pet rabbits. The research was focused on 16 rabbits that had been diagnosed with dental disease based on clinical and paraclinical examination, we obtained samples from the dental injury site using a sterile cotton swab and followed up with bacteriological examination and antibiotic sensitivity testing for identifying the bacteria and the resistances. Out of 16 samples sent to the laboratory for testing, 4 were negative (25%), showing no bacterial growth, from the rest of the samples the following bacterial strains were identified: 18,75% Staphylococcus spp, 18,75% Streptococcus spp, 6,25% Streptococcus β hemolytic, 6,25% Pseudomonas aeruginosa, 6,25% Klebsiella spp. 3 cases presented with multiple-strain infection as follows: 6,25% Streptobacillus spp and Klebsiella spp; 6,25% Proteus spp and Streptoccus spp; 6,25% Pseudomonas spp and Streptoccus spp. After obtaining the antibiotic sensitivity test results, we found that the most efficient drug was Amikacin, no bacteria presented resistance to this medicine, and it was followed by Trimethoprim/sulfa (TMPS) and Ciprofloxacin. All the identified bacterial strains were presenting resistance to Amphotericin and Clindamycin. Antimicrobial resistance and the limited availability of veterinary-use-approved drugs constitute strong arguments that sustain the importance of this study in the management of dental disease in pet rabbits.  

Clinical and radiologic diagnosis in dental disease in pet rabbits

Rabbits became more and more popular pets these last few years. For assuring their good health and wellbeing both the owners and the veterinarians are equally responsible. Sudden change in diet or inadequate nutrients, poor husbandry or stressing factors can all cause complex systemic pathologies to appear that often start at the oral cavity and the teeth. The aim of this study was to identify and apply the most accurate methods of approach, restrain, examination and diagnosis in dental disease in pet rabbits. This study included 19 rabbits, one of them clinically healthy and 18 were identified with dental disease. The patients had multiple affections but we categorized them according to the primary disease. 6 of them presented with pathologies of the incisors (31.57%), 10 had issues starting with the premolars (52.63%) and 2 with the molars (10.52%). The highest rate was 52.63% represented by the ones that presented dental disease at the premolars. The most met pathology in this study was odontogenic abscess formation in 11 out of 19 cases (57.89%), in most cases the abscesses appeared secondary due to periodontal infections. Knowing the specific features of the oral cavity, of the approach and the restraining methods as well as the clinical and imagistic diagnosing can assure proper management of dental disease in pet rabbits.