scholarly journals Comparision of Different Raw Densities and Board Thicknesses in the Production of Enzymatically Bonded Fiberboards

2017 ◽  
Vol 6 (2) ◽  
pp. 69
Author(s):  
Alexander Kirsch ◽  
Patrick Reuter ◽  
Alireza Kharazipour ◽  
Markus Euring
Keyword(s):  
Construction Materials ◽  
Modulus Of Rupture ◽  
Thickness Swelling ◽  
European Standard ◽  
Bonding Agents ◽  
Uf Resin ◽  
Binding Agents ◽  
Mediator System ◽  
Health Related

Reducing CO2 emissions for the long term is an important issue in countering climate change. For this reason, the use of renewable construction materials inter alia wood-based materials is becoming increasingly important. Wood based materials often depend on petrochemical-based binding agents, most of which contain and emit formaldehyde. This causes environmental and health-related difficulties that could be rectified by avoiding the utilization of these adhesives. For this purpose, enzymatically bonded medium-density fiberboards (MDF) with a targeted raw density of 650 kg/m³ and 750 kg/m³ and high-density fiberboards (HDF) with a density of 900 kg/m³ were produced in different thicknesses. Laccase-Mediator-System (LMS) was applied to manufacture the boards and to compare them to those glued with UF and inactivated laccase, respectively. These panels were tested in terms of their physical technical properties, such as internal bond strength (IB), modulus of rupture (MOR) and thickness swelling (TS) after 24 h immersion. The aim was to show the correlation between density and these properties for fiberboards bonded this way. Most panels meet the requirements of the European standard when LMS and UF-resin were used. The possibility to produce fiberboards bonded with alternative bonding agents opens up the way to alternative, innovative, healthy and environmental-friendly wood based products.

scholarly journals Physico-Mechanical and Biological Durability of Citric Acid-Bonded Rubberwood Particleboard

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 98
Author(s):  
Zhou Huaxu ◽  
Lee Seng Hua ◽  
Paridah Md Tahir ◽  
Zaidon Ashaari ◽  
Syeed SaifulAzry Osman Al-Edrus ◽  
...  
Keyword(s):  
Citric Acid ◽  
Acid Content ◽  
Urea Formaldehyde ◽  
Modulus Of Rupture ◽  
Thickness Swelling ◽  
Peak Intensity ◽  
Uf Resin ◽  
Citric Acid Content ◽  
Acidic Nature ◽  
Biological Durability

This study investigated the effects of different citric acid content on the physico-mechanical and biological durability of rubberwood particleboard. Particleboards with density of 700 kg/m3 were produced with three different citric acid contents, namely 10, 15 and 20 wt%. Particleboards made from 10 wt% urea formaldehyde (UF) resin were served as control for comparison purposes. FTIR analysis was carried out and the formation of ester linkages between -OH on cellulose and carbonyl groups of citric acid was confirmed. The peak intensity increased along with increasing citric content, which indicated that a higher amount of ester linkages were formed at higher citric acid content. Citric acid-bonded particleboard had inferior physical properties (water absorption and thickness swelling) and mechanical properties (internal bonding strength, modulus of rupture and modulus of elasticity) compared to that of the UF-bonded particleboard. However, the performance of particleboard was enhanced with increasing citric acid content. Meanwhile, citric acid-bonded particleboard displayed significantly better fungal and termite resistance than UF-bonded particleboard owing to the acidic nature of citric acid. It can be concluded that citric acid is a suitable green binder for particleboard but some improvement is needed during the particleboard production process.

scholarly journals Kualitas Papan Partikel Dari Pelepah Nipah dengan Perekat Asam Sitrat dan Sukrosa

2016 ◽  
Vol 10 (2) ◽  
pp. 129
Author(s):  
Mahdi Santoso ◽  
Ragil Widyorini ◽  
Tibertus Agus Prayitno ◽  
Joko Sulistyo
Keyword(s):  
Surface Roughness ◽  
Citric Acid ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Thickness Swelling ◽  
Nypa Fruticans ◽  
Binding Agents ◽  
Press Time ◽  
Positive Effect

Penggunaan perekat alami dan bahan baku non kayu dalam pembuatan papan partikel masih sangat terbatas. Sukrosa dan asam sitrat adalah dua bahan alami yang potensial sebagai perekat alami pengganti perekat sintetik berbasis formaldehida. Nipah (Nypa fruticans Wurmb.) merupakan bahan non kayu yang potensial dijadikan alternatif bahan baku papan partikel. Penelitian ini bertujuan untuk mengetahui kualitas papan partikel pelepah nipah yang direkat dengan sukrosa/asam sitrat (100/0, 87,5/12,5 dan 75/25). Papan partikel yang dibuat berukuran 25 cm × 25 cm × 1 cm, target kerapatan 0,8 g/cm3. Variabel perekatan antara lain jumlah perekat 20%, waktu kempa 10 menit, suhu kempa 180°C dan tekanan spesifik 3,6 MPa. Sifat fisika dan mekanika papan partikel diuji berdasarkan standar JIS A 5908:2003, kekasaran permukaan diukur menggunakan metode yang dilakukan oleh Hiziroglu (1996). Hasil penelitian menunjukkan bahwa penambahan asam sitrat terhadap sukrosa berpengaruh positif terhadap sebagian besar sifat papan partikel pelepah nipah. Papan partikel pelepah nipah dengan perekat sukrosa/asam sitrat 87,5/12,5 mampu memberikan hasil terbaik dengan memenuhi standar JIS A 5908:2003. Karakteristik papan partikel tersebut adalah kerapatan 0,89 g/cm3, kadar air 10,21%, pengembangan tebal 2,45%, penyerapan air 23,55%, kekasaran permukaan 5,13 μm, keteguhan rekat internal 0,39 MPa, keteguhan patah 9,80 MPa dan keteguhan elastisitas 3,19 GPa.Kata kunci: papan partikel, pelepah nipah, perekat alami, sukrosa, asam sitrat AbstractUtilization of natural binder for non-wood composite is still limited. Sucrose and citric acid are potential natural binding agents for composite products. Nipa (Nypa fruticans Wurmb.) was non-wood materials which are potentially to be used as an alternative raw material for particleboards. This study aimed to determine the quality of the nipa frond particleboard bonded with sucrose/citric acid (100/0, 87.5/12.5 and 75/25). Particleboards were manufactured in 25 cm × 25 cm × 1 cm dimension, the target of density 0.8 g/cm3. The variables included resin content of 20%, press time of 10 m, pressing temperature of 180°C and specific pressure of 3.6 MPa. The physics and mechanics properties of particleboard were tested in accordance to standard JIS A 5908:2003 and surface roughness was measured by following the method performed by Hiziroglu (1996). The results showed that the addition of citric acid to sucrose give a positive effect on most of the properties of the nipa frond particleboards. The particleboard bonded with sucrose/citric acid 87.5/12.5 was able to provide the best results to meet the standards of JIS A 5908: 2003. Characteristics of the particleboard was a density of 0.89 g/cm, moisture content of 10.21%, thickness swelling of 2.45%, water absorption of 23.55%, surface roughness of 5.13 ìm, internal bonding of 0.39 MPa, modulus of rupture of 9.80 MPa and modulus of elasticity of 3.19 GPa.

scholarly journals Study of Homogeneous Chipboard Manufacturing u sing Betung Bamboo (Dendrocalamus Asper) Mixed with Polyethylene Addictive

2021 ◽  
Vol 11 (2) ◽  
pp. 68-71
Author(s):  
Salman Salim ◽  
◽  
Mona Lena Abdul Aziz ◽  
Sufyan Abdullah ◽  
Mohamad Hairi Osman ◽  
...  
Keyword(s):  
Water Absorption ◽  
Peninsular Malaysia ◽  
Modulus Of Rupture ◽  
Medium Density ◽  
Bamboo Species ◽  
Thickness Swelling ◽  
European Standard ◽  
Climate Conditions ◽  
Dendrocalamus Asper ◽  
Scientific Name

Bamboo is an evergreen plant native to Asia and America that grows at every altitude, even in unideal climate conditions. Betung bamboo or its scientific name Dendrocalamus Asper is one of the bamboo species that are easily found in peninsular Malaysia. This study examined the characteristics of Betung bamboo and its potential to manufacture chipboard. Several tests were conducted, namely modulus of elastic (MOE), modulus of rupture (MOR), thickness swelling (TS), and water absorption (WA) to evaluate the potential of Betung bamboo as the primary material in the manufacture of chipboard mixed with polyethylene as additive are the parameters considered. This study found that the composition of 70% bamboo and 30% polyethylene was produced optimum chipboard which met BS EN standards (British and European Standard). It was also found that the MOE and MOR values of the resulting chipboard exceeded the medium density board standards. For WA and TS values, the chipboard achieved the standard requirements. Thus, this study concludes that chipboard made of Betung bamboo with the addition of polyethylene is suitable to be applied for internal and external doors, and internal paneling for any commercial or domestic building and furniture.

scholarly journals Particleboards from Recycled Pallets

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1597
Author(s):  
Ján Iždinský ◽  
Ladislav Reinprecht ◽  
Zuzana Vidholdová
Keyword(s):  
Urea Formaldehyde ◽  
Brown Rot ◽  
Decay Resistance ◽  
Modulus Of Rupture ◽  
Thickness Swelling ◽  
Uf Resin ◽  
Worldwide Production ◽  
Negative Effect ◽  
Growth Activity ◽  
Serpula Lacrymans

Worldwide production of wooden pallets continually increases, and therefore in future higher number of damaged pallets need to be recycled. One way to conveniently recycle pallets is their use for the production of particleboards (PBs). The 3-layer PBs, bonded with urea-formaldehyde (UF) resin, were prepared in laboratory conditions using particles from fresh spruce logs (FSL) and recycled spruce pallets (RSP) in mutual weight ratios of 100:0, 80:20, 50:50 and 0:100. Particles from RSP did not affect the moisture properties of PBs, i.e., the thickness swelling (TS) and water absorption (WA). The mechanical properties of PBs based on particles from RSP significantly worsened: the modulus of rupture (MOR) in bending from 14.6 MPa up to 10 MPa, the modulus of elasticity (MOE) in bending from 2616 MPa up to 2012 MPa, and the internal bond (IB) from 0.79 MPa up to 0.61 MPa. Particles from RSP had only a slight negative effect on the decay resistance of PBs to the brown-rot fungus Serpula lacrymans, while their presence in surfaces of PBs did not affect the growth activity of moulds at all.

scholarly journals Optimum condition of manufacturing hybrid particleboard from mixture of cocoa pod husk and bamboo particles

2019 ◽  
Vol 18 (03) ◽  
pp. 10-15
Author(s):  
Hong T. K. Tang
Keyword(s):  
Surface Layer ◽  
Core Layer ◽  
Test Methods ◽  
General Purpose ◽  
Raw Material ◽  
Modulus Of Rupture ◽  
Thickness Swelling ◽  
Material Source ◽  
Uf Resin ◽  
Cocoa Pod Husks

This study was to investigate the feasibility of using cocoa pod husks (CPH) and bamboo in manufacturing hybrid particle board. Three-layer experimental particleboards from mixture of bamboo and CPH participles were manufactured using different surface to core layer ratios (30, 40 and 50%) and various UF ratios for surface layer (6, 8 and 10%) and for core layer (4, 6 and 8%). Modulus of rupture (MOR), internal bond strength (IB) and thickness swelling (TS) properties of the boards were evaluated based on Standard TCVN7756:2007 Test Methods for general purpose used in dry conditions. The results showed that boards in all ratios of surface to core layer investigated could be manufactured using up till 8% UF resin for surface layer and up till 6% UF resin for core layer without falling below the minimum Standard VN7754:2007. The optimal condition was the surface to core layer ratio of 30% used with 9.51% UF resin for surface layer and 7.45% UF resin for core layer obtaining the lowest thickness swelling (TS) 11.13%. The highest values of MOR and IB were 15.25 MPa and 0.45 MPa, respectively. This study demonstrates that cocoa pod husks and bamboo waste can be an alternative raw material source for particleboard production.

Thrombopoietin Receptor Agonists in Children with Immune Thrombocytopenia: A New Therapeutic Era

2020 ◽  
Vol 20 ◽  
Author(s):  
Giuseppe Lassandro ◽  
Valentina Palladino ◽  
Giovanni Carlo Del Vecchioa ◽  
Viviana Valeria Palmieri ◽  
Paola Carmela Corallo ◽  
...  
Keyword(s):  
Immune Thrombocytopenia ◽  
Treatment Options ◽  
Thrombopoietin Receptor Agonists ◽  
Receptor Agonists ◽  
Thrombopoietin Receptor ◽  
Related Quality ◽  
Health Related

Background and Objective: Immune thrombocytopenia (ITP) is a common bleeding disorder in childhood. The management of ITP in children is controversial, requiring personalized assessment of patients and therapeutic choices. Thrombopoietin receptor agonists (TPO-RAs), eltrombopag and romiplostim, have been shown to be safety and effective for the treatment of pediatric ITP. The aim of our research is defining the role of thrombopoietin receptor agonists in the management of pediatric ITP. Method: This review focuses on the use of TPO-RAs in pediatric ITP, in randomized trials and in clinical routine, highlighting their key role in management of the disease. Results: Eltrombopag and romiplostim appear effective treatment options for children with ITP. Several clinical studies have assessed that the use of TPO-RAs increases platelet count, decreases bleeding symptoms and improves health-related quality of life. Moreover, TPO-RAs are well tolerated with minor side effects. Conclusion: Although TPO-RAs long term efficacy and safety still require further investigations, their use is gradually expanding in clinical practice of children with ITP.

scholarly journals The impact of lymphedema on health-related quality of life up to 10 years after breast cancer treatment

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Mads G. Jørgensen ◽  
Navid M. Toyserkani ◽  
Frederik G. Hansen ◽  
Anette Bygum ◽  
Jens A. Sørensen
Keyword(s):  
Breast Cancer ◽  
Quality Of Life ◽  
Cancer Treatment ◽  
Breast Cancer Treatment ◽  
Health Related Quality ◽  
Related Quality ◽  
Health Related ◽  
The Impact

AbstractThe impact of breast cancer-related lymphedema (BCRL) on long-term quality of life is unknown. The aim of this study was to investigate the impact of BCRL on health-related quality of life (HRQoL) up to 10 years after breast cancer treatment. This regional population-based study enrolled patients treated for breast cancer with axillary lymph node dissection between January 1st 2007 and December 31th 2017. Follow up and assessments of the included patients were conducted between January 2019 and May 2020. The study outcome was HRQoL, evaluated with the Lymphedema Functioning, Disability and Health Questionnaire, the Disabilities of the Arm, Shoulder and Hand Questionnaire and the Short Form (36) Health Survey Questionnaire. Multivariate linear logistic regression models adjusted for confounders provided mean score differences (MDs) with 95% confidence intervals in each HRQoL scale and item. This study enrolled 244 patients with BCRL and 823 patients without BCRL. Patients with BCRL had significantly poorer HRQoL than patients without BCRL in 16 out of 18 HRQoL subscales, for example, in physical function (MDs 27, 95%CI: 24; 30), mental health (MDs 24, 95%CI: 21; 27) and social role functioning (MDs 20, 95%CI: 17; 23). Age, BMI, BCRL severity, hand and dominant arm affection had only minor impact on HRQoL (MDs < 5), suggesting a high degree of inter-individual variation in coping with lymphedema. This study showed that BCRL is associated with long-term impairments in HRQoL, especially affecting the physical and psychosocial domains. Surprisingly, BCRL diagnosis rather than clinical severity drove the largest impairments in HRQoL.

scholarly journals Primary Prevention of Dementia: An Ethical Review

2020 ◽  
pp. 1-10
Author(s):  
Dorothee Horstkötter ◽  
Kay Deckers ◽  
Sebastian Köhler
Keyword(s):  
Synergistic Effects ◽  
Well Being ◽  
Ethical Review ◽  
Medical Risk ◽  
Medical Risk Factors ◽  
Societal Challenges ◽  
Dementia Prevention ◽  
Health Related ◽  
Personal Level

Dementia poses important medical and societal challenges, and of all health risks people face in life, dementia is one of the most feared. Recent research indicates that up to about 40% of all cases of dementia might be preventable. A series of environmental, social, and medical risk-factors have been identified and that should be targeted from midlife onwards when people are still cognitively healthy. At first glance, this seems not merely advisable, but even imperative. However, these new developments trigger a series of new ethical questions and concerns which have hardly been addressed to date. Pro-active ethical reflection, however, is crucial to ensure that the interests and well-being of those affected, ultimately all of us, are adequately respected. This is the goal of the current contribution. Against the background of a concrete case in primary dementia prevention, it provides a systematic overview of the current ethical literature and sketches an ethical research agenda. First, possible benefits of increased well-being must be balanced with the burdens of being engaged in particularly long-term interventions for which it is unclear whether they will ever pay out on a personal level. Second, while knowledge about one’s options to maintain brain health might empower people, it might also undermine autonomy, put high social pressure on people, medicalize healthy adults, and stigmatize those who still develop dementia. Third, while synergistic effects might occur, the ideals of dementia prevention might also conflict with other health and non-health related values people hold in life.

scholarly journals A Conceptual Model of Long-Term Weight Loss Maintenance: The Importance of Cognitive, Empirical and Computational Approaches

2021 ◽  
Vol 18 (2) ◽  
pp. 635
Author(s):  
Darren Haywood ◽  
Blake J. Lawrence ◽  
Frank D. Baughman ◽  
Barbara A. Mullan
Keyword(s):  
Weight Loss ◽  
Weight Loss Maintenance ◽  
Computational Approaches ◽  
Healthy Habits ◽  
Health Related ◽  
The One ◽  
Major Factors ◽  
Positive Social Support ◽  
Weight Loss Interventions

Living with obesity is related to numerous negative health outcomes, including various cancers, type II diabetes, and cardiovascular disease. Although much is known about the factors associated with obesity, and a range of weight loss interventions have been established, changing health-related behaviours to positively affect obesity outcomes has proven difficult. In this paper, we first draw together major factors that have emerged within the literature on weight loss to describe a new conceptual framework of long-term weight loss maintenance. Key to this framework is the suggestion that increased positive social support influences a reduction in psychosocial stress, and that this has the effect of promoting better executive functioning which in turn facilitates the development of healthy habits and the breaking of unhealthy habits, leading to improved ongoing maintenance of weight loss. We then outline how the use of computational approaches are an essential next step, to more rigorously test conceptual frameworks, such as the one we propose, and the benefits that a mixture of conceptual, empirical and computational approaches offer to the field of health psychology.

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