Effect of Variable Conditions of Exposure on the Physical and Mechanical Properties of Blockboards

The growing demand for wood and the continued increase of the raw material price have resulted in companies using more efficient wood resources in wood-based products such as blockboard. These boards are used in the field of interior design, especially. The aim of this research was to evaluate the effect of variable environmental conditions on the physical and mechanical properties of blockboard (BK). Two types of commercial BK were exposed in variable environmental conditions (kitchen, bathroom and climatic chamber) for three months. The BK structures were composed of veneer (V) and high-density fibreboards (HDF) for the face sheets and glued, solid wood, resinous strips for the core. The temperature and relative humidity of the air (RH) ranged from 18 °C to 25 °C and from 25% to 90%, respectively. In the climatic chamber (CC), the dynamics of the parameter variations were different than in the other two exposure climates, being determined by the programmed cyclic changes in RH. The changes observed on physical and mechanical properties were more extreme for the blockboards tested in the CC than in the kitchen (K) and bathroom (Ba). After 3 months of exposure in the CC, the thickness and weight of the boards increased by 1.8 and 1.1 times, respectively, for veneered BK, and by 4.4 and 0.4 times, for BK with HDF faces, compared to values recorded in the kitchen. The panels exposed in the CC exhibited the highest increase in moisture content (MC): 41% for veneered BK and 82% for BK with HDF faces after three months of exposure, followed by those exposed in the bathroom and kitchen. Increases in MC determined decreases of flexural properties and soundness surfaces, more evident for HDF face structures compared to V ones.

Remote video monitoring for offshore sea farms: Reliability and availability evaluation and image quality assessment via laboratory tests

<div class="page" title="Page 1"><div class="section"><div class="layoutArea"><div class="column"><p class="Abstract">In this article, the availability and reliability of a remote video monitoring system for offshore sea farming plants are studied and tested in laboratory. The scope of the system is to ensure a video surveillance infrastructure so to supervise breeding cages along with the fish inside them, in order to contrast undesired phenomena like fish poaching as well as cages damages. The system is installed on a cage floating structure: it is mainly composed of an IP camera that is controlled by a Raspberry Pi Zero which is the core of the system. Images are streamed thanks to a 3G/4G dongle, while the overall system is powered via two photovoltaic panels charging a backup battery. Simulations are carried out considering two seasonal functioning periods (i.e., winter and summer): each of them is characterised by temperature trends defined according to the average temperatures of the system deployment site, 8 km offshore the city of Piombino, Italy. In order to optimise power consumption without hindering application scenario requirements, the system operates according to a duty cycle of 2 minutes out of 15 (i.e., 8 minutes of operation per hour). The performances of the system are then tested in laboratory exploiting a climatic chamber so to simulate different environmental conditions: variations on image quality are then analysed in order to identify possible dependencies on critical situations related to specific temperature and relative humidity values and to the presence of salt in the air.</p></div></div></div></div>

A Low-Cost, Easy-to-Assemble Device to Prevent Infant Hyperthermia under Conditions of High Thermal Stress

High ambient temperature and humidity greatly increase the risk of hyperthermia and mortality, particularly in infants, who are especially prone to dehydration. World areas at high risk of heat stress include many of the low- and middle-income countries (LMICs) where most of their inhabitants have no access to air conditioning. This study aimed to design, evaluate, and test a novel low-cost and easy-to-assemble device aimed at preventing the risk of infant hyperthermia in LMICs. The device is based on optimizing negative heat transfer from a small amount of ice and transferring it directly to the infant by airflow of refrigerated air. As a proof of concept, a device was assembled mainly using recycled materials, and its performance was assessed under laboratory-controlled conditions in a climatic chamber mimicking realistic stress conditions of high temperature and humidity. The device, which can be assembled by any layperson using easily available materials, provided sufficient refrigerating capacity for several hours from just 1–2 kg of ice obtained from a domestic freezer. Thus, application of this novel device may serve to attenuate the adverse effects of heat stress in infants, particularly in the context of the evolving climatic change trends.

Comparative characteristics of the main sanogenetic mechanisms in large laboratory animals (pigs) with acute blood loss and after infusion of an isotonic colloidal solution based on dextran and an isotonic solution based on polyglucin in conditions of general external cooling

The experiment was carried out on male pigs, which in the operating room were simulated with acute blood loss (air temperature 23oC). Then the animals were placed in a climatic chamber (minus 50 ° C) for 10 minutes. Then the temperature in the climatic chamber was raised to minus 10 ° C and the introduction of the test solutions to the animals began. It was found that in both groups there were similar indicators of blood pressure. The heart rate and respiratory rate in animals in the group with the experimental solution based on polyglucin derivatives were lower than in the group with the solution based on dextran. Key words: external general cooling, pigs, blood pressure, heart rate, respiratory rate, infusion solution.

Design, construction and implementation of relative humidity and temperature climatic chamber for metrology laboratory

For the calibration of thermohygrometers it is necessary to have a means of generating temperature and relative humidity for this reason in this development we will build a climatic chamber which will generate and control these two magnitudes. For the generation of temperature a thermoresistance was used and the decrease of relative humidity was done through a silica gel trap through which the air inside the chamber is recirculated with the use of a vacuum pump. On the other hand, an ultrasonic humidity generator also known as fogger was used to increase the relative humidity. For the construction of the chamber, acrylic was used as the main material, since it is translucent and facilitates the visualization of the thermohygrometers’ indications. For the control of the process variables such as temperature and relative humidity, an Arduino card was used, which through PWM pulse width modulation, the control was performed achieving a variation of 0.3 °C and 2 %RH, which will be evaluated by an accredited laboratory in the characterization of isothermal media certified by ONAC, since it is in this way that the inhomogeneity, stability and thermal load of the medium, components that affect the uncertainty of the instruments under calibration, are evaluated. It should be remembered that this development was carried out in order to create an air medium with which temperature and relative humidity measuring instruments can be calibrated in the metrology laboratory VALIDACIONES Y METROLOGIA LM S.A.S., since it is in the process of growth and one of its main objectives is to be accredited in the magnitudes of temperature and relative humidity before the accreditation body in Colombia (ONAC), which is the entity that will finally give the technical approval to release the chamber and put it into operation.

Environment Influence on the Properties of Functional Parts Made of HIPS Material

The aim of this work is to study the climatic influences on 3D printed materials. This study focuses on the HIPS material, which was chosen as the starting material for further studies. The material in the field of 3D printing is known for its rapid photooxidation, which results in the formation of cracks in the final product. A climatic chamber was used for degradation, in which UV light, heat and increased humidity were applied to the material. The degree of degradation was then checked by tensile test and electron microscope.

Evaluation of the Thermofluidic Performance of Climatic Chambers: Numerical and Experimental Studies

Climatic chambers are highly important in research and industrial applications and are used to examine manufactured samples, specimens, or components in controlled environment conditions. Despite the growing industrial demand for climatic chambers, only a few published studies have specifically concentrated on performance analysis and functional improvements through numerical and experimental studies. In this study, a 3D computational fluid dynamics (CFD) model of a climatic chamber was developed using Ansys Fluent to simulate the fluid flow, heat, and mass transfer to obtain the velocity, temperature, and relative humidity fields in the interior box of a 1200 L climatic chamber. The results were then validated with experimental data from a prototype. Finally, the heat losses of the surrounding components of the chamber were calculated, and the relationship between the inside temperature and the overall thermal loss was modelled. This validated numerical model provides the possibility of optimising the performance of climate chambers by reducing the thermal loss from the walls and modifying the air flow pattern inside the chamber.

NEW TEST RIG FOR MEASURING THE FRICTION TORQUE OF GEARBOXES IN EXTREME THERMAL CONDITIONS

A new test rig for tribological tests was developed and manufactured. It consists of a mobile device for measurement of the start-up friction torque of transmissions, in particular planetary gearboxes, and the friction torque in dynamically steady conditions, as well as a climatic chamber to stabilize the temperature of the tested gearbox in its extreme range: from -50 to +50°C. In the series of devices for tribological tests, developed and manufactured at the Institute, the new test rig is marked with the symbol T-34. The verification results correspond with the churning losses related to the viscosity characteristics of the lubricating oils. As the temperature increases, both the start-up friction torque and the friction torque under dynamically steady conditions decrease.

Impact of temperature humidity index (THI) on physiological responses and milk yield of Tharparkar and Karan Fries cows exposed to controlled environment

Tharparkar and Karan Fries cows were exposed to 25°C, 35°C and 42°C with relative humidity of 50±5%, corresponding to THI of 72.2, 85.3 and 91.0, respectively for three hours continuously for three days consecutively in the control climatic chamber. At THI of 91.0, physiological responses i.e. RR/ min, PR/min and RT (°F) increased by 14, 13, and 1.18 in Tharparkar and 23, 14 and 2.98 in Karan Fries cows, respectively over pre exposure values. At THI of 91.0, the surface body temperature was increased over THI 72.2 by 5.21 to 7.52°C in Tharparkar and 7.45 to 8.42°C in Karan Fries cows. Skin blood flow of Karan Fries cows was increased by 4.98, 4.15 and 3.95 PU at THI 85.3 and 6.84, 9.18 and 8.04 PU at 91 THI over the pre exposure values of respective THI at dorsal, ventral and ear part of body, respectively. The decrease in milk yield was calculated in the THI range of 72.2 - 91.0, the milk yield was decrease (per unit increase in THI) by 135.11ml in Karan Fries and 51.60 ml in Tharparkar cows. The results of the study clearly indicated the more sensitivity of Karan Fries compared to Tharparkar cows at higher THI. Therefore, Karan Fries cows needs protection from extreme heat for sustained production performance.

Influence of conversion coatings on the resistance of adhesive joints to undercorrosion

The paper deals with the application of conversion coatings for the preparation of surfaces before adhesive bonding of galvanized and non-galvanized steels. The morphology of the coatings was monitored by electron microscopy. The corrosion characteristics of the conversion coatings were determined by linear polarization. Steels treated with conversion coatings were used to form bonded joints using three structural adhesives. The resistance of the joints to undercorrosion was determined following the change in the load-bearing capacity of the joints after exposure in the climatic chamber.