Characteristics of the Pressing Process and Density Profile of MUPF-Bonded Particleboards Produced from Waste Plywood.

Waste plywood containing phenol-formaldehyde (PF) resin is one of the materials that are difficult to use in the production of particleboards based on UF resin. Therefore, the aim of this research was to analyze the possibility of using this type of waste in the production of particleboards bonded with melamine-urea-phenol-formaldehyde (MUPF) resin in order to determine their suitability for particleboard production. The pressing process and density profile of three-layer particleboards were presented. The press closing time for mats containing only recovered particles in the core layer (100%), produced with a face layer ratio of 50%, a resin load for a face layer of 12%, and a core layer of 10%, at a unit pressure of 3 MPa, was 29% shorter than for the industrial particle mats. Regardless of the level of variability of independent factors, the heating time of the mats containing recovered particles was 10-20% shorter than the heating time of the mats with industrial particles. The greatest impact on the maximum density of the face layer of particleboards was observed for the content of the recovered particles and then the resin load. The maximum density area of the face layer was located closer to the surface in particleboards produced with a higher (80%, 100%) content of the recovered particles, a higher (i.e., 12% and 10%, respectively, for face and core layers) resin load, a lower (35%) face layer ratio, and a higher (3 MPa) unit pressure.

Influence of Thermal Modification in Nitrogen Atmosphere on the Selected Mechanical Properties of Black Poplar Wood (Populus nigra L.).

The thermal modification of wood in a nitrogen atmosphere shapes the functional properties of wood. The aim of this research was to determine the influence of different levels of temperature and the duration of thermal modification on the mechanical properties of the black poplar (Populus nigra L.). Black poplar was thermally modified in nitrogen atmosphere in the temperature range from 160 °C to 220 °C (6 levels) for 2 h to 8 h (4 levels), resulting in a total of 24 treatments. The effect of these treatments on compressive strength parallel to the grain (CS), modulus of rupture (MOR), and modulus of elasticity during bending (MOE) were analyzed. Thermal modification influenced the mechanical properties of black poplar wood. After thermal modification occurred in a nitrogen atmosphere, an increase in compressive strength was noticeable for all variants of black poplar wood modification. The highest 16% increase in CS was obtained for the modification carried out at the temperature of 160 °C and for 2 h. An increase was also found for MOE when modified under mild conditions, while a decrease occurred for variants at higher temperatures, i.e., for 200 °C and 220 °C. The study showed that for all modification variants, there was a decrease in MOR alongside the increase in modification temperature and time.

Temperature, Time, and Interactions between Them in Relation to Colour Parameters of Black Poplar (Populus nigra L.) Thermally Modified in Nitrogen Atmosphere.

Thermal modification of wood in nitrogen atmosphere permits its usability value to be improved. The aim of the research was to determine the impact of technological modification parameters at different levels on the colour of black poplar (Populus nigra L.). Black poplar was thermally modified in nitrogen atmosphere at a range of temperatures from 160 °C to 220 °C, at times between 2 h and 8 h. The parameters of wood colour were measured according to the CIE L*a*b* colour space model. The changes in a* and b* had a non-linear profile. The maximum value of a* for black poplar wood was achieved after a modification at the temperature of 200 °C, while the maximum value of the b* parameter was achieved after modification at 190 °C. Colour changes in the ΔE of black poplar after modification at 160 °C and 170 °C were similar, and the dynamics of changes increased after modification at the temperature of 180 °C. The highest value of ΔE, around 40, was observed after modification at the temperature of 220 °C and time of 8 h. There were no statistically significant differences between the ΔE for radial and tangential sections. Statistical analysis showed that modification temperature was responsible for the variability of the L* value in 90%, and in ca. 70% for the changes in parameters a* and b*. The influence of the modification time on the colour parameters was minor-below 4%. The influence of the interaction between modification temperature and time on the colour parameters was below 10%. As a consequence, in the case of ΔE of black poplar wood, the influence of temperature was at a level of ca. 80%. On the other hand, the influence of time and the interaction between temperature and time of modification was low-below 3%.

Evaluation of the Dimensional Stability of Black Poplar Wood Modified Thermally in Nitrogen Atmosphere.

Black poplar (Populus nigra L.) was thermally modified in nitrogen atmosphere. The effects of the modification process on poplar wood were evaluated for temperatures: 160 °C, 190 °C, and 220 °C applied for 2 h; and 160 °C and 190 °C for 6 h. The percentual impact of temperature and time of modification on the properties of modified wood was analysed. The study permitted the identification correlations between the chemical composition and selected physical properties of thermally modified poplar wood. The dimensional stability of poplar wood was improved after thermal modification in nitrogen. The higher the temperature of modification, the lower the equilibrium moisture content (EMC) of black poplar. At the temperature of 220 °C, EMC was two times lower than the EMC of non-modified black poplar. It is also possible to reduce the dimensional changes of wood two-fold (at the modification temperature of 220 °C), both in radial and tangential directions, independently of the acclimatization conditions (from 34% to 98% relative humidity, RH). Similar correlations have been found for wood that has been soaked in water. Higher modification temperatures and longer processing times contributed to a lower swelling anisotropy (SA).

Non-adaptive reaction to disease - coping, demographic variables and trauma symptoms in cancer patients.

OBJECTIVES: The aim of the presented study was to determine the relations of styles and strategies of coping with stress and demographic variables with the intensity of PTSD symptoms in persons diagnosed with cancer. The study tried to determine which style of coping with stress is the best predictor of posttraumatic symptoms in the group. METHODS: This study was conducted on the group of 150 patients (55 females and 95 males) that were treated for cancer. Polish version of the Mini-Mental Adjustment to Cancer Scale - mini-MAC - was used to study styles of coping with stress. PTSD Inventory (PTSD-C) allowing for the quantitative estimation of the symptoms was used measure the intensity of PTSD symptoms. Additionally, a demographic questionnaire containing the questions about the age, sex, education, and the time since the diagnosis was employed for the benefits of this study. RESULTS: The results of the study indicate non-adaptive function of destructive style. In the situation of being subjected to a traumatic event this style is propitious to the development of the symptoms of posttraumatic stress disorder. The individual strategies of coping, sex and age are correlated with higher intensity of posttraumatic symptoms in sick persons. CONCLUSIONS: Destructive style, of coping with stress is less beneficial for the adaptation to a cancerous disease. It may significantly influence the development of pathological symptoms characteristic to PTSD.

Emotional reactivity, coping style and cancer trauma symptoms.

INTRODUCTION: This article studies the relationship between emotional reactivity and coping style on the one hand and intensity of symptoms of trauma in adult patients with cancer on the other hand. MATERIAL AND METHODS: The study was conducted on 150 patients, 55 women and 95 men, hospitalized for diagnosed cancer. Temperament was assessed with the Formal Characteristics of Behaviour - Temperament Inventory (FCB-TI). Coping style was assessed with the Polish version of the Mental Adjustment to Cancer Scale (Mini-MAC). Intensity of intrusion/hyperarousal and avoidance/numbing was assessed with the Factorial Version Inventory (PTSD), a quantitative measure of trauma-related symptoms. RESULTS: The outcomes of this study suggest that individual coping style is what determines the intensity of trauma-related symptoms most strongly. Destructive coping style accounts for 49% of the variance of symptom intensity and emotional reactivity accounts for 6%. Combined, destructive coping style and emotional reactivity account for 55% of the variance of general post-traumatic stress symptoms. CONCLUSIONS: Destructive coping style (more important determinant of trauma symptoms) and high emotional reactivity as one of temperament traits are conducive to intensification of cancer trauma symptoms in adult patients. Our findings suggest that constructive coping style and low emotional reactivity may act as a specific protector against cancer trauma symptoms in adults.