| 1. |
- Bari, Ehsan, et al.
(författare)
-
Failure characteristics of thermally modified poplar wood subjected to mechanical tests
- 2023
-
Ingår i: IRG documents database and compendium. - : International Research Group of Wood Protection.
-
Konferensbidrag (refereegranskat)abstract
- Poplar (Populus spp.) are among the fastest growing timber species and have been widely planted for use in plywood, composites, pallets, furniture components and paper production. However, the low density of the wood limits many structural applications and the wood has little resistance to biodegradation. Thermal modification represents one approach to improving durability by changing the moisture behavior of the wood, but it can also have adverse effects on structural performance. Understanding the potential effects of thermal treatment on poplar properties can help define the most appropriate applications for these materials. Poplar timbers from Iran were subjected to 30 or 60 min of thermal treatment at temperatures ranging from 110 to 220 °C. Samples were then evaluated for mass loss during treatment, changes in flexural properties, e.g., modulus of elasticity (MOE) and modulus of rupture (MOR), the degree of polymerization, and water absorption characteristics. MOR of controls subjected to 100 °C were similar to those exposed to 160 °C, while MOE was more variable with a slight upward trend for samples exposed to a given heating regime for only 30 min. The increases in MOE may be related to changes in cellulose crystallinity. Mass losses increased with increasing temperature exposure while moisture absorption decreased as expected with longer thermal exposure. The degree of polymerization remained similar for samples exposed up to 170 °C and then increased at higher temperatures. The increases may reflect the complete destruction of shorter chain polymers, leaving only the heat-resistant longer chain polymers. The results suggest that poplar can be thermally modified within limited parameters to improve some performance attributes without adversely affecting its structural capacity.
|
|
| 2. |
- Bari, Ehsan, et al.
(författare)
-
Fungal behavior and recent developments in biopulping technology
- 2024
-
Ingår i: World Journal of Microbiology & Biotechnology. - : Springer Nature. - 0959-3993 .- 1573-0972. ; 40:7
-
Tidskriftsartikel (refereegranskat)abstract
- Biological pretreatment of wood chips by fungi is a well-known approach prior to mechanical- or chemical pulp production. For this biological approach, a limited number of white-rot fungi with an ability to colonize and selectively degrade lignin are used to pretreat wood chips allowing the remaining cellulose to be processed for further applications. Biopulping is an environmentally friendly technology that can reduce the energy consumption of traditional pulping processes. Fungal pretreatment also reduces the pitch content in the wood chips and improves the pulp quality in terms of brightness, strength, and bleachability. The bleached biopulps are easier to refine compared to pulps produced by conventional methodology. In the last decades, biopulping has been scaled up with pilot trials towards industrial level, with optimization of several intermediate steps and improvement of economic feasibility. Nevertheless, fundamental knowledge on the biochemical mechanisms involved in biopulping is still lacking. Overall, biopulping technology has advanced rapidly during recent decades and pilot mill trials have been implemented. The use of fungi as pretreatment for pulp production is in line with modern circular economy strategies and can be implemented in existing production plants. In this review, we discuss some recent advances in biopulping technology, which can improve mechanical-, chemical-, and organosolv pulping processes along with their mechanisms.
|
|
| 3. |
- Ghorbanian Far, Mohammad, et al.
(författare)
-
Physical and mechanical properties of different beech wood species grown at various climate conditions: a review
- 2024
-
Ingår i: Holzforschung. - : Walter de Gruyter. - 0018-3830 .- 1437-434X. ; 78:7, s. 377-386
-
Forskningsöversikt (refereegranskat)abstract
- Beech wood, renowned for its diverse applications spanning construction, flooring, furniture, veneer, and plywood, holds a paramount position among industrial wood species. Nevertheless, the myriad of beech species worldwide, coupled with the dynamic impact of climate change, have produced structural variations within beech trees. Extensive research has scrutinized the physical and mechanical attributes of beech wood species across the globe. Findings reveal distinguishable mechanical strength, yet increased density leads to notable rates of shrinkage and swelling, somewhat constraining its utility in select domains. Identifying research gaps can create new efforts aimed at exploiting the potential of these wood resources. This paper outperforms a mere exploration of beech wood properties over the past two decades; it delves into the ramifications of climatic fluctuations, temperature shifts, wind dynamics, and soil composition. Given the lack of a comprehensive compendium documenting the full range of physical, mechanical, and microscopic attributes of the Fagus genus, this paper aims to compile information that integrates this multifaceted information.
|
|
| 4. |
- Maqbool, Shazia, et al.
(författare)
-
Construction and validation of ShaMaq developmental screening tool
- 2024
-
Ingår i: Child Care Health and Development. - : John Wiley & Sons. - 0305-1862 .- 1365-2214. ; 50:1
-
Tidskriftsartikel (refereegranskat)abstract
- IntroductionThe diagnosis of developmental delay and early intervention ameliorates long-term sequelae. There is a need for an appropriate, regionally adapted and reliable developmental screening tool to be used in low and middle-income countries with scarce resources.AimThe aim of this research is to construct and validate a screening tool for identifying developmental delay in Pakistani children.MethodShaMaq developmental screening tool (SDST) was developed consisting of five proformas to be administered at different age groups: 6-8 weeks (Group 1), 6-10 months (Group 2), 18-24 months (Group 3), 3-3.5 years (Group 4), and 4.5-5.5 years (Group 5). On an average, Groups 1-3 took 10-15 min, whereas Groups 4 and 5 took 20-25 min. We sampled children between the ages of 6 weeks to 5.5 years and tested them all within their designated age groups. Internal consistency was assessed by Cronbach's alpha. Interobserver testing was done for reliability and concurrent validity was undertaken by using the senior consultant developmental paediatrician's final diagnosis as the gold standard.ResultsOut of 550 healthy children, 8-19% in the five groups were found to have some form of developmental delay using SDST. Approximately 50% of the families were in the low-to-moderate income bracket, and nearly 93% lived in a joint family system. Internal consistency of items in the five groups ranged from 0.784 to 0.940, whereas both interobserver reliability and concurrent validity ranged from 0.737 to 1.0. SDST showed 94.4% sensitivity and 92.9% specificity.ConclusionSDST is an effective tool for identifying delay in healthy children with good internal consistency, reliability, and validity.
|
|
| 5. |
- Zahid, Nida, et al.
(författare)
-
Psychosocial factors influencing quality of life in patients with primary brain tumors in Pakistan : an analytical cross-sectional study
- 2023
-
Ingår i: BMC Research Notes. - : Springer Nature. - 1756-0500. ; 16:1
-
Tidskriftsartikel (refereegranskat)abstract
- ObjectiveDespite quality of life (QoL) being recognized as an important outcome in neuro-oncology, there is a lack of research from Pakistan where sociocultural differences may influence QoL. This study aimed to measure the QoL in patients with primary brain tumors (PBTs) and assess its association with mental health outcomes and social support.ResultsOur study included a total of 250 patients, with a median age of 42 years (range 33-54 years). The commonest brain tumors were glioma (46.8%) and meningioma (21.2). The mean global QoL of the sample was 75.73 +/- 14.9. The majority of patients had high social support (97.6%) and were not depressed (90%) or anxious (91.6%).On multivariable linear regression, global QoL was inversely associated with no or low income (beta coefficients: -8.75 to -11.84), having hypertension (-5.53), currently using a urine catheter (-13.55), having low social support (-28.16) suffering from mild (-15.31) or symptomatic (-23.84) depression, or mild anxiety (-13.22).
|
|
