Mechanical properties of heat-treated wooden material utilized in the construction of outdoor sitting furniture

Effects of impregnation with Imersol-AQUA on the bending strength of some wood materials

ICU patients have an increased risk of joint stiffness because of their critical illness and reduced mobility. There is a paucity of evidence evaluating the efficacy of passive movements (PMs). We investigated whether PMs prevent or reduce joint stiffness in ICU patients. A randomized, controlled, within-participant, assessor-blinded study. A 48-bed tertiary care adult ICU. Intubated patients who were expected to be invasively mechanically ventilated for greater than 48 hours with an ICU length of stay greater than or equal to 5 days, and unable to voluntarily move their limbs through full range of motion (ROM). The ankle and elbow on one side of each participant's body received PMs (10 min each joint, morning and afternoon, 5 d/wk). The other side acted as the control. The PMs intervention continued for as long as clinically indicated to a maximum of 4 weeks. The primary outcome was ankle dorsiflexion ROM at cessation of PMs. Plantarflexion, elbow flexion and extension ROM, and participant-reported joint pain and stiffness (verbal analog scale [VAS]) were also measured. Outcomes were recorded at baseline and cessation of PMs. For participants whose PMs intervention ceased early due to recovery, additional post-early-cessation of PMs review measurements were undertaken as near as possible to 4 weeks. We analyzed data from 25 participants with a median (interquartile range) ICU stay of 15.6 days (11.3-25.4). The mean (95% CI) between-side difference for dorsiflexion ROM (with knee extension) at cessation of PMs was 0.4 degrees (-4.4 to 5.2; p = 0.882), favoring the intervention side, indicating there was not a clinically meaningful effect of 5 degrees. No statistically significant differences were found between the intervention and control sides for any ROM or VAS data. PMs, as provided to this sample of medium to long-stay ICU patients, did not prevent or reduce joint stiffness.

Bu çalışmada, ağaç malzemelerin hava kurusu yoğunluk ve eğilme direnci üzerine farklı yöntem ve sıcaklık koşullarında uygulanan ısıl işlemlerin etkisi analiz edilmiştir. Sarıçam (Pinus silvestris L.) ve kayın (Fagus sylvatica L.) odunu örnekleri ThermoWood, yağlı işlem ve sıcak hava yöntemleri kullanılarak üç farklı sıcaklıkta (170 °C, 190 °C ve 210 °C) ayrı ayrı ısıl işleme tabi tutulmuştur. Deney örneklerinin yoğunluk ve eğilme direnci sırası ile TS 2472 ve TS 2474 esaslarına uyularak belirlenmiştir. Araştırma sonuçlarına göre, ısıl işlem yöntemi ve işlem sıcaklığındaki farklılaşma ahşap örneklerin yoğunluk ve eğilme direnci değerleri üzerinde önemli bulunmuştur. Isıl işlem yöntemi açısından, her iki ağaç türü için en yüksek yoğunluk ve eğilme direnci yağlı ısıl işlem görmüş örneklerde elde edilmiştir. Ayrıca, sıcak hava yöntemine göre ThermoWood yöntemi ile işlem görmüş örneklerde daha yüksek direnç değerleri bulunmuştur. Tüm yöntemler için, ısıl işlem sıcaklığındaki artışa bağlı olarak ahşap örneklerde yoğunluk ve eğilme direnci değerleri azalmıştır. Sıcaklık artışından kaynaklanan yoğunluk ve direnç kayıpları yağlı ısıl işlem yönteminde en az seviyede iken, sıcak hava yönteminde en fazla orana sahiptir.

The effect of commercial heat treatment on physical and mechanical properties of compression wood (CW) and opposite wood (OW) of black pine (Pinus nigra Arnold) was investigated. Black pine logs containing CW were cut parallel to the pith and separated into CW and OW sections. A commercial heat treatment process was applied to pine lumber at 180 and 210 ºC for 3 hours. Water absorption (WA), contact angle (CA), swelling, modulus of rupture (MOR), modulus of elasticity (MOE), and impact bending strength (IBS) were measured. The results showed that heat treatment decreased water absorption and swelling of the CW and OW of black pine. Heat treatment at 210 °C temperature decreased the longitudinal swelling of CW by 51.4%. Higher immersion time lowered the effect of heat treatment on the WA values. The CA values of the CW and OW increased due to heat treatment. Heat treatment reduced the MOR, MOE, and IBS values. The results indicated that MOR, MOE, and CA values were highly affected in the CW; on the other hand, the IBS value was highly affected in the OW by heat treatment compared to control groups. The results indicate that heat-stabilized CW can be used more widely and effectively in the forest products industry.

The aim of the study was to determine the effects of different heat treatment and varnish application combinations on hardness, scratch resistance, and glossiness of wood materials sampled from limba (Terminalia superba), iroko (Chlorophora excelsa), ash (Fraxinus excelsior L.), and Anatolian chestnut (Castenea sativa Mill.) species. The heat treatment was applied at two levels (150 and 180 oC) for both 3 and 6 hour periods. After the heat treatment, four types of varnish (cellulose lacquer, synthetic varnish, polyurethane varnish, and water based varnish) were applied, and hardness, scratch resistance, and glossiness of varnish film layers of the treated woods were measured. The effects of heat treatment and varnish combination applications on above mentioned variables were analyzed according to the study design (factorial design with 4 (species) x 2 (heat) x 2(duration) x 4 (varnish) = 64 experimental units) with 10 samples for each combination of parameters. Glossiness increased on wood samples for all of the four wood species treated with cellulose lacquer and synthetic varnish and across all heating treatments. However, glossiness values were decreased for all the wood species depending on heating temperature and time. Values of hardness and scratch resistance were also decreased for all the four wood species across all the treatment combinations. The results were obtained from the upper surface of the application process and are thought to contribute to the national economy.

Purpose The purpose of this study is to analyze the titanium alloy under heat treated condition. Titanium alloy heat treatment, particularly Ti‐6Al‐4V alloy, has been an important field of study due to its wide variety of uses in the aerospace, automotive, and biomedical sectors. The mechanical characteristics of titanium alloys are heavily influenced by their microstructure. Cold‐rolled Ti‐alloys have strong bending and tensile strength due to extensive β‐phase precipitation on the α matrix. However, various heat treatment (HT) methods can affect the mechanical characteristics. The current study seeks to investigate the effects of various heat treatment procedures on the microstructural and mechanical changes of Ti‐6Al‐4V alloy, in order to achieve an optimal balance of strength, hardness, and ductility for a variety of real-world applications. Design/methodology/approach Three plates of Ti‐6Al‐4V alloy were heated above the β‐transus temperature for a certain period and then cooled via furnace, air, and sand. One extra plate was kept in ‘untreated’ condition and given name ‘as received’ plate. The three heat treated plates were evaluated and compared with ‘as received’ plate based on tensile strength, bending strength, hardness, and microstructural changes. Findings A considerable change in orientation of α and β was noted through optical microscopy upon heat treatment. The mechanical testing revealed that all the cooling methods adopted in the study have reduced the UTS and increased the YS of the plates. The ductility of the alloy was primarily enhanced by 'air cooling' and 'sand cooling' methods. Originality/value Notably, the hardness test findings indicated a significant drop in hardness for the ‘sand‐cooled’ sample. Furthermore, the ‘air cooled’ sample showed the maximum hardness due to the production of acicular α regions.

Black pine (Pinus nigra) has high industrial usage potential and large plantation in Turkey. Larch wood was treated with heat to determine its mechanical properties, such as bending strength and pressure and order to determine its adhesion strength. Laminating adhesives are used for the construction of polyvinyl acetate and polyurethane. Heat treatment was applied to the samples at 100-150°C for 4 h in drying oven. In the result of the experiments, heat treated samples give better results due to temperature increase.   Key words: Heat treatment, bending strength, compression strength, bonding strength, black pine.

The results of experimental studies to determine the effect of alloying and heat treatment on the mechanical properties of the high-chromium cast iron are described. When alloying the melt with nickel, molybdenum and manganese, as well as during heat treatment by quenching, specific wear, tensile strength in bending of the obtained samples, their hardness and microhardness were studied. A comparative analysis of the influence of alloying elements and heat treatment methods has been performed. When alloying Ni, Mo, and Mn, cast specimens that have not undergone heat treatment have the highest specific wear. It was established that the hardened Ni alloyed samples have the greatest bending strength. It was found that cast samples that were not subjected to heat treatment have much lower hardness and microhardness. The approximate composition of chromium cast iron was determined for further studies to increase its wear resistance. The research results are used in the manufacturing process of parts for crushing and grinding equipment.

This study assessed the comprehensive assessment of flexural and fatigue strength of the three-dimensional (3D)-printed polylactic acid (PLA) samples across diverse printing designs and parameters. The experiment framework included a diverse array of printing parameters: layer heights, first layer thicknesses, infill densities, top/bottom infill patterns, extruder temperatures, perimeters, and types of solid layer top and bottom. Our findings suggest that there is an interplay between these parameters and the mechanical properties of PLA specimens. Notably, the fatigue strength of PLA printing specimens is more significantly influenced (0.44%) by an increase in the thickness of the first layer compared to flexural strength (87%). The rate of increase in bending strength is lower in cases of layer height (3.55%) and initial layer height (0.44%) in contrast with other factors. Specimens with an initial layer thickness of 0.4 mm reached the highest number of cycles until failure, recording 21 022 cycles. Furthermore, the study identifies the infill pattern’s impact on strength, highlighting that the line infill pattern type case has the highest bending strength of 75.97 MPa and surpasses the honeycomb pattern in bending strength. Compared to the Honeycomb pattern, the rectilinear design has 2.1% higher bending strength. The number of cycles to failure of the rectilinear pattern is greater than those of the honeycomb pattern. In comparison to other patterns, the Rectilinear Top/Bottom infill pattern has a higher interest rate of 27.5% for bending strength and 200.83% for fatigue strength. Additionally, greater bending and flexural strength are obtained by raising the solid layer top, bottom, and perimeter values, respectively. In comparison to the other temperatures, the bending strength and fatigue strength are highest at 200 °C. Therefore, the first layer height of 0.4 mm, the top/bottom rectilinear infill pattern, the extruder temperature of 200 °C, the perimeter value of 3, the solid layer/top value of 3, and the solid layer/bottom value of 3 are the optimal values for the part subjected to at the same time bending strength combined with fatigue strength. This comprehensive study may provide a broader and deeper understanding of individual and combined effects on an overview of the bending and fatigue strength in connection to printing design and printing parameters, as well as the ideal optimal parameters for 3D printing with the PLA material. Manufacturers and designers can use the recommended parameters to optimize the strength of their printed parts, considering both bending and fatigue performance.

To investigate the impact of various heat treatments on the strength and toughness of TA15 aviation titanium alloys, five different heat treatment methods were employed in the temperature range of 810–995 °C. The microstructure of the alloy was examined using a scanning electron microscope (SEM) and X-ray diffraction (XRD), and its mechanical properties were analyzed through tensile, hardness, impact, and bending tests. The findings indicate that increasing the annealing temperature results in an increase in the phase boundary and secondary α phase, while the volume fraction of the primary α phase decreases, leading to a rise in hardness and a decrease in elongation. The tensile strength of heat-treated samples at 810 °C was notably improved, displaying high ductility at this annealing temperature. Heat treatment (810 °C/2 h/WQ) produced the highest tensile properties (ultimate tensile strength, yield strength, and elongation of 987 MPa, 886 MPa, and 17.78%, respectively). Higher heat treatment temperatures were found to enhance hardness but decrease the tensile properties, bending strength, and impact toughness. The triple heat treatment (810 °C/1 h/AC + 810 °C/1 h/AC + 810 °C/1 h/AC) resulted in the highest hardness of 601.3 MPa. These results demonstrate that various heat treatments have a substantial impact on the strength and toughness of forged TA15 titanium alloys.

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the causative agent of Coronavirus diseases-2019 (COVID-19) disease. Rapid and accurate detection of the virus is vital to prevent transmission and effectively manage the pandemic. The gold standard diagnostic method for this agent is the real-time reverse transcription polymerase chain reaction (qrRT-PCR) test conducted on respiratory tract samples and one of the most critical steps affecting the sensitivity of this test is the nucleic acid extraction stage. However, restrictive factors such as reagent supply and storage conditions limit the testing capacity. Therefore, innovative and cost-effective alternatives are needed to speed up testing and minimize pre-processing steps. The aim of this study was to evaluate the impact and applicability of different methods to enhance the efficiency of the nucleic acid extraction stage in the SARS-CoV-2 qrRT-PCR test. As an alternative to the routinely used viral nucleic acid extraction buffer (vNAT), the modified vNAT method (MvNAT), which includes centrifugation, the R1-R2 kit and the heat treatment (HT) method, was applied to 118 respiratory tract samples. Samples determined with threshold cycle values of (Cq) of ≤ 35 (n= 10), > 35 (n= 42), indeterminate (n= 56) in routine results and negative controls (n= 10) were included in the study. The RNA quantities obtained after extraction for each method were measured and recorded using a spectrophotometric measurement device. All samples were processed using the SARS-CoV-2 qrRT-PCR kit targeting the RdRp region. The results were statistically analyzed using unpaired and paired t-tests and results with a p-value of < 0.05 were considered statistically significant. Excluding negative control samples, while the standard method yielded a Cq value of 48.1% (mean Cq value (Cqmean)= 39.5 ± 6.9) for a total of 108 samples, the MvNAT method produced a Cq value of 11.1% (Cqmean= 38.4 ± 5.2), the R1-R2 kit yielded 14.8% (Cqmean= 35.9 ± 7.1) and HT method resulted in 25% (Cqmean= 31.4 ± 6.3). When the variability in target gene Cq values was analyzed in all samples compared to the standard method, the HT method significantly provided lower Cq values (n= 16; p= 0.007; paired t-test) while the MvNAT method and R1-R2 kit yielded higher Cq values (n= 6; p= 0.025, n= 11; p= 0.004; paired t-test). Sensitivity rates were MvNAT= 31.6%, R1-R2= 57.9%, HT= 84.2%, with 100% specificity for all three methods. The HT method demonstrated a positive extraction efficiency because it is fast, easy and not dependent on reagents. Although this method provided lower Cq values than the standard method, especially in samples with a high viral load, it should be considered that it also has the potential to yield false-negative results in samples with Cq> 35. With this study, it was concluded that the extraction phase of the SARS-CoV-2 qrRT-PCR test can be carried out using various methods that do not require kits or reagents, such as the HT method. However, it is believed that multicenter studies involving a larger number of samples are necessary to standardize the test and assess the possibility of false negatives.

The effects of cross-sectional geometry and force direction on bending strength (MOR) and modulus of elasticity (MOE) were investigated in selected softwoods. The specimens were constructed of Scots pine (Pinus sylvestris), Black pine (Pinus nigra), Siberian pine (Pinus sibirica), Stone pine (Pinus pinea), Nordmann fir (Abies nordmanniana), Oriental spruce (Picea orientalis), and Lebanon cedar (Cedrus libani). A total of 280 specimens were prepared from these seven species in two different cross-sectional geometries (circular and square, equal in area) and tested in two characteristic force directions (tangential and radial) by 10 replications. They were subjected to three-point bending tests according to TS 2474 (2005) and TS 2478 (2005) to obtain the MOR and MOE. The results showed that the type of cross-sectional area and direction of applied force, individually or together, had considerable effects on the MOR and MOE. The MOR values of the circular-sectioned specimens were 5% greater than those of the square-sectioned specimens. The MOE values of the circular-sectioned specimens were on average 19% greater than those of the square-sectioned specimens. The MOR and MOE values were on average 7% and 17% greater, respectively, for the force applied in the tangential direction.

Low-temperature sintering of porous silicon carbide ceramic support with SDBS as sintering aid

Citrus chilling injury causes 25% postharvest losses by shortening its storage life and lowers its market value in developed countries. In citrus fruits, chilling injury is characterized by increased moisture loss and disease susceptibility. The present study was conducted with the objective to evaluate the effects of pre-storage heat treatments (HTS: control, 5, 10, 15 and 20 min), heat treatment methods (HTM: wet heat treatment [WHT], vapor heat treatment [VHT]), and exposure temperatures (ET: chilled [2.5 °C], non-chilled [10 °C]) on citrus fruits (cv. Blood Red having sour orange rootstock) during 2015–2016 at the University of Agriculture, Peshawar, Pakistan. Sweet orange fruits and fruit discs of 10 mm diameter were simultaneously treated with WHT and VHT. The heat treated fruits and fruit discs were separated into two lots. One lot was held at non-chilling temperature (10 ± 1 °C), while the other lot was exposed to chilling temperature (2.5 ± 1 °C) for 75 days and packed in fiber board packages. The fruits and fruit discs after 75 days storage at both storage temperatures (10 ± 1 °C and 2.5 ± 1 °C) were incubated at ambient temperature for 7 days (simulated marketing time) and analyzed for different chilling injury parameters. Heat treatment periods (HTS), exposure temperature (ET) and their interactions (HTS × ET) showed significant (p ≤ 0.05) differences for the majority of the traits. The interaction of HTS × HTM was significant (p ≤ 0.05) for weight loss and surface pitting. However, heat treatment methods (HTM) and interaction of ET × HTM × HTS was significant for surface pitting and weight loss, respectively. The non-chilled (10 ± 1 °C) fruits revealed lower weight loss (6.80%), surface pitting (4.40%), disease incidence (7.07%), disease expansion (3.97 mm), ion leakage (15.77%) while the ascorbic acid increased (32.38 mg 100 g−1). However, chilling (2.5 °C) triggered the increase in weight loss (8.32%), surface pitting (16.13%), disease incidence (14.59%), lesion diameter (10.37 mm) and ion leakage (27.96%) in sweet orange. Heat treatments with WHT and VHT for 5–10 min resulted in reduced weight loss (6.07%), surface pitting (3.33%), disease incidence (2.00%), disease expansion (5.00 mm) and ion leakage (20.23%) in sweet oranges. Heat treatments with WHT and VHT for 15–20 min, accelerated the fruit senescence by increasing the weight loss (8.98%), surface pitting (15.67%), disease incidence (15.33%), disease expansion (8.33 mm) and ion leakage (23.62%). In comparison to heat treatment methods, highest weight loss (7.57%), surface pitting (11.53%), ion leakage (21.94%) and disease incidence (10.86%) were recorded in VHT, whereas WHT treatments had lowest weight loss (7.55%), surface pitting (9.00%), ions leakage (21.80%) and disease incidence (10.79%). Therefore, modest WHT pre-storage heat treatment (5–10 min) is recommended for storage of sweet orange.

The aim of this study was to investigate the effect of wood species, heat treatment, adhesive type and joint technique on shear force capacity of H-type furniture joints. For this purpose, an experimental design that consisted of 3 wood species, 2 treatment processes (untreated, heat-treated), 2 adhesive types (polyurethane (PUR), polyvinyl acetate (PVAc)) and 2 joint techniques (dowel, mortise-tenon (MT)) and 5 replications for each group were prepared, and accordingly, a total of 120 specimens were tested under static shear loads. Siberian pine (Pinus sibirica), Iroko (Chlorophora excelsa), and common ash (Fraxinus excelsior), which are commonly used in furniture constructions, were used as wood species. In general, iroko showed the highest shear force capacity between the wood species. The specimens constructed of heat-treated wood species showed lower shear force capacity by approximately 15 % in comparison to the same untreated specimens. MT joints showed better performance than dowel joints higher by approximately 21 %. PVAc adhesive gave higher values than PU adhesive by around 5 %. According to the results of four-way interactions, highest shear force capacities of H-type joints were obtained from “Common ash-PVAc-MT” combination in groups of untreated specimens and from “Iroko-PU-MT” combination in groups of heat-treated specimens.