scholarly journals Role of Leaf Litter in Above-Ground Wood Decay

2020 ◽  
Vol 8 (5) ◽  
pp. 696 ◽  
Author(s):  
Grant T. Kirker ◽  
Amy Bishell ◽  
Jed Cappellazzi ◽  
Jonathan Palmer ◽  
Nathan Bechle ◽  
...  
Keyword(s):  
Moisture Content ◽  
Leaf Litter ◽  
Wood Decay ◽  
Fungal Colonization ◽  
Sequencing Analysis ◽  
Visual Evaluation ◽  
Guild Composition ◽  
Aged Leaf ◽  
Decay Development ◽  
Over Time

The effects of leaf litter on moisture content and fungal decay development in above-ground wood specimens were assessed. Untreated southern pine specimens were exposed with or without leaf litter contact. Two types of leaf litter were evaluated; aged (decomposed) and young (early stages of decomposition). The moisture content of specimens was monitored, and specimens were periodically removed for visual evaluation of decay development. In addition, amplicon-based sequencing analysis of specimens and associated leaf litter was conducted at two time points. Contact with either type of leaf litter resulted in consistently higher moisture contents than those not in contact with leaf litter. Visually, evident decay developed most rapidly in specimens in contact with the aged leaf litter. Analysis of amplicon-based sequencing revealed that leaf litter contributes a significant amount of the available wood decay fungal community with similar communities found in the litter exposed wood and litter itself, but dissimilar community profiles from unexposed wood. Dominant species and guild composition shifted over time, beginning initially with more leaf saprophytes (ascomycetes) and over time shifting to more wood rotting fungi (basidiomycetes). These results highlight the importance of the contributions of leaf litter to fungal colonization and subsequent decay hazard for above-ground wood.

scholarly journals Temperature influence on creep of reinforced concrete

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Edmilson Lira Madureira ◽  
Brenda Vieira Costa Fontes
Keyword(s):  
Reinforced Concrete ◽  
Moisture Content ◽  
Alternative Model ◽  
Sustained Load ◽  
Structural Members ◽  
Temperature Influence ◽  
Stress Increase ◽  
Concrete Members ◽  
Over Time ◽  
Creep Strains

abstract: The creep of concrete promotes strains over time in structural members kept under sustained load. It causes the stress decrease on the concrete and the steel stress increase in reinforced concrete members. The moisture content and temperature influence significantly such phenomenon. The creep strains model of the NBR 6118/2014 [1] is, applicable, solely, to those cases of constant stress magnitudes. Reinforced concrete members exhibit variations on the stress magnitudes and, in this way, requires the use of an alternative model for the prediction of the creep strains as the so known the State Model. This report refers itself to temperature influence analysis upon creep strains of reinforced concrete structural members. The results have revealed that temperature speeds up the creep effects and, in this way, the steel yielding caused by the stress increase on the reinforcement bars occurs at earlier ages.

scholarly journals Study of Changes in Physical Parameters of compost and vermicompost of Eucalyptus leaf litters

2018 ◽  
Vol 4 (1) ◽  
pp. 34-40
Author(s):  
Ritu Nagar ◽  
Anurag Titov ◽  
Praveesh Bhati
Keyword(s):  
Moisture Content ◽  
Leaf Litter ◽  
Initial Temperature ◽  
Cattle Dung ◽  
Physical Parameters ◽  
Physical Factors ◽  
Eudrilus Eugeniae ◽  
Minimum Level ◽  
Metabolic Heat ◽  
Later Phase

Vermicompost and compost of leaf litter of Eucalyptus was studied in plastic bins in duplicate sets with two different proportions (100 % and 50 %). For vermicompost experiments, epigeic earthworm species Eisenia foetida and Eudrilus eugeniae were employed at 10-10 numbers each per vermicompost bins. Cattle dung was taken as control. During the entire process physical factors viz. temperature, pH, moisture content and biomass were measured and compaired. The results were reveal that initial temperature was 35°C ± 2°C in both vermicompost and compost leaf litter and after several weeks, it was set at minimum level. In 50 % leaf litter temperature was 2-3°C higher than 100 % leaf litter. pH of both vermicompost and compost mixtures were acidic in beginning phase while set at alkaline at final stage. Vermicompost had lower pH than compost. Moisture content of leaf litter also decreased in initial phase due to generation of metabolic heat but at later phase it was increased due to decreasing of metabolic heat. More changed was seen in 100 % leaf litter followed by 50 % and then cattle dung. Biomass of leaf litter was more decreased in 100 % waste then 50 % and cattle dung.

California Almond Shelf Life: Changes in Moisture Content and Textural Quality During Storage

2019 ◽  
Vol 62 (3) ◽  
pp. 661-671 ◽  
Author(s):  
Jia Wu ◽  
Xiangyang Lin ◽  
Shengnan Lin ◽  
Paul Chen ◽  
Guangwei Huang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Storage Temperature ◽  
Initial Moisture Content ◽  
Textural Properties ◽  
Storage Conditions ◽  
Temperature And Humidity ◽  
Lower Temperature ◽  
And Storage ◽  
Over Time

Abstract. The effects of packaging and storage conditions on the moisture content and instrumental and sensory textural properties of raw and salty light roasted (SLR) California almonds were studied under different storage conditions. The controlled combinations included low, medium, and high temperatures and low and high relative humidity (RH). Almond samples were packaged in cartons or polyethylene (PE) bags with and without vacuum. Both absorption and desorption of moisture by almonds were observed during storage and were dependent on the packaging and storage conditions. In general, gradual changes were observed for samples with PE and vacuum PE packaging in most of the storage conditions, while the samples packed in cartons showed more dramatic changes because these unprotected samples were more vulnerable to seasonal changes in humidity. The SLR almonds showed consistent moisture gains, while the raw almonds tended to lose moisture content in most of the storage conditions. This may be attributed to the low initial moisture content of the SLR samples. All raw samples packed in cartons became softer over time. The softening tended to be enhanced by high storage humidity and temperature. The raw almonds packaged in PE bags were firmer than those packed in cartons but also became softer over time. The firmness of the SLR samples was generally lower than that of raw samples, probably because roasting reduced the density and mechanical strength of the kernels. The firmness of PE packaged SLR samples increased in uncontrolled storage conditions and in higher storage temperature and humidity conditions but decreased slightly in lower temperature and humidity conditions. Vacuum packaging did not affect the firmness much. Using PE packaging and maintaining the RH below 50% and the temperature below 25°C are effective in stabilizing both raw and processed almonds. Keywords: Almond, Firmness, Nonpareil, Packaging, Relative humidity, Sensory, Storage, Temperature, Texture.

scholarly journals Studies into Fungal Decay of Wood In Ground Contact—Part 1: The Influence of Water-Holding Capacity, Moisture Content, and Temperature of Soil Substrates on Fungal Decay of Selected Timbers

Forests ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1284
Author(s):  
Brendan Nicholas Marais ◽  
Christian Brischke ◽  
Holger Militz ◽  
Johann Hinrich Peters ◽  
Lena Reinhardt
Keyword(s):  
Moisture Content ◽  
Wood Species ◽  
General Trend ◽  
Wood Decay ◽  
European Beech ◽  
Water Holding Capacity ◽  
Inoculum Potential ◽  
Ground Contact ◽  
Fungal Decay ◽  
Water Holding

This article presents the results from two separate studies investigating the decay of wood in ground contact using adapted versions of laboratory-based terrestrial microcosm (TMC) tests according to CEN/TS 15083-2:2005. The first study (A) sought to isolate the effect of soil water-holding capacity (WHCsoil [%]) and soil moisture content (MCsoil [%WHCsoil]) on the decay of five commercially important wood species; European beech (Fagus sylvatica), English oak heartwood (Quercus robur), Norway spruce (Picea abies), Douglas-fir heartwood (Pseudotsuga menziesii), and Scots pine sapwood (Pinus sylvestris), while keeping soil temperature (Tsoil) constant. Combinations of soil mixtures with WHCsoil of 30%, 60%, and 90%, and MCsoil of 30%, 70%, and 95%WHCsoil were utilized. A general trend showed higher wood decay, measured in oven-dry mass loss (MLwood [%]), for specimens of all species incubated in soils with WHCsoil of 60% and 90% compared to 30%. Furthermore, drier soils (MCsoil of 30 and 70%WHCsoil) showed higher MLwood compared to wetter soils (95%WHCsoil). The second study (B) built on the first’s findings, and sought to isolate the effect of Tsoil and MCsoil on the decay of European beech wood, while keeping WHCsoil constant. The study used constant incubation temperature intervals (Tsoil), 5–40 °C, and alternating intervals of 10/20, 10/30, and 20/30 °C. A general trend showed drier MCsoil (60%WHCsoil), and Tsoil of 20–40 °C, delivered high wood decay (MLwood > 20%). Higher MCsoil (90%WHCsoil) and Tsoil of 5–10 °C, delivered low wood decay (MLwood < 5%). Alternating Tsoil generally delivered less MLwood compared to their mean constant Tsoil counterparts (15, 20, 25 °C). The results suggest that differences in wood species and inoculum potential (WHCsoil) between sites, as well as changes in MCsoil and Tsoil attributed to daily and seasonal weather patterns can influence in-ground wood decay rate.

Colonization and decomposition of salal (Gaultheria shallon) leaf litter by saprobic fungi in successional forests on coastal British Columbia

2008 ◽  
Vol 54 (6) ◽  
pp. 427-434 ◽  
Author(s):  
Takashi Osono ◽  
Susumu Iwamoto ◽  
John A. Trofymow
Keyword(s):  
British Columbia ◽  
Leaf Area ◽  
Leaf Litter ◽  
Fungal Colonization ◽  
Gaultheria Shallon ◽  
Food Web Structure ◽  
Old Growth ◽  
Saprobic Fungi ◽  
Clear Cut ◽  
Recalcitrant Compounds

The colonization of leaf litter by saprobic fungi was studied in old-growth and post-harvest successional Douglas-fir forests on southeast Vancouver Island, British Columbia. This study focused on leaf litter of salal ( Gaultheria shallon Pursh.), a dominant understory shrub in all stands. Salal litter is characterized by the occurrence of bleached portions attributable to fungal colonization of the litter and to the variable decomposition of recalcitrant compounds, such as lignin. Analyses of proximate chemical fractions, fungal assemblages on the bleached leaf area, and pure culture decomposition assays indicated that Marasmius sp. and Coccomyces sp. were responsible for rapid decomposition and bleaching of salal leaf litter. The bleached area accounted for 17%–22% of total area of salal leaf litter collected in immature (40–60 years old), mature (85–105 years old), and old-growth (more than 290 years old) stands, but for only 2% in regeneration (5–15 years old) stands. The reduction of bleached leaf area occupied by Marasmius sp. and Coccomyces sp. in regeneration stands could be due to the changes in microenvironmental conditions on the forest floor, in litter quality, or in food-web structure in soils. The decrease of fungi able to decay recalcitrant compounds may lead to a reduction of salal decomposition rates in clear-cut sites that would persist until canopy closure occurs.

Bacterial and fungal community composition over time in chicken litter with high or low moisture content

2012 ◽  
Vol 53 (5) ◽  
pp. 561-569 ◽  
Author(s):  
S. Wadud ◽  
A. Michaelsen ◽  
E. Gallagher ◽  
G. Parcsi ◽  
O. Zemb ◽  
...  
Keyword(s):  
Moisture Content ◽  
Community Composition ◽  
Fungal Community ◽  
Fungal Community Composition ◽  
Chicken Litter ◽  
Over Time

Characteristics and DBP formation of dissolved organic matter from leachates of fresh and aged leaf litter

Chemosphere ◽  
2016 ◽  
Vol 152 ◽  
pp. 335-344 ◽  
Author(s):  
Qianyun Jian ◽  
Treavor H. Boyer ◽  
Xiuhong Yang ◽  
Beicheng Xia ◽  
Xin Yang
Keyword(s):  
Organic Matter ◽  
Dissolved Organic Matter ◽  
Leaf Litter ◽  
Aged Leaf

Effects of leaf litter and its fungal colonization on the diet of Limnomysis benedeni (Crustacea: Mysida)

Hydrobiologia ◽  
2009 ◽  
Vol 636 (1) ◽  
pp. 439-447 ◽  
Author(s):  
Christine Aßmann ◽  
Eric von Elert ◽  
René Gergs
Keyword(s):  
Leaf Litter ◽  
Fungal Colonization ◽  
Limnomysis Benedeni

scholarly journals Damage risk assessment of building materials with moisture hysteresis

2021 ◽  
Vol 2069 (1) ◽  
pp. 012043
Author(s):  
Michele Libralato ◽  
Alessandra De Angelis ◽  
Paola D’Agaro ◽  
Giovanni Cortella ◽  
Menghao Qin ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Building Materials ◽  
Moisture Transfer ◽  
Lower Boundary ◽  
Wood Decay ◽  
Simplified Models ◽  
Desorption Curve ◽  
Decay Risk ◽  
Adsorption Curve

Abstract Heat and Moisture Transfer (HMT) simulations are used to evaluate moisture related damage risks in building envelopes. HMT simulations are commonly performed accepting the hypothesis of not considering the moisture hysteresis of materials. The results of HMT simulation of a timber wall with hysteresis are presented, and compared to the results of three simplified models, showing the effects of hysteresis on the simulation results and on the assessment of the risk of decay. Moisture content is the most influenced variable, while temperature and relative humidity are slightly affected. The wood decay risk analysis is performed using the simplified 20% moisture content rule. Similar temperature values and relative humidity values are calculated as simplified models, while the moisture content annual average values have differences up to 2.3%. The wood decay risk obtained with the simplified models could be overestimated if the simulation is performed using the desorption curve, while it could be underestimated with the adsorption curve. The best approximation is obtained with the mean sorption curve, while the desorption curve and the adsorption curve could be used to calculate the upper and lower boundary of the moisture contents respectively.

scholarly journals Measurements behind Internal Insulation on Solid Masonry Walls with Different Orientations and Degrees of Repair in a Danish Multi-story Building

2020 ◽  
Vol 172 ◽  
pp. 01008
Author(s):  
Lies Vanhoutteghem ◽  
Britt Haker Høegh ◽  
Thor Hansen
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Energy Use ◽  
Wood Decay ◽  
Large Temperature ◽  
Mould Growth ◽  
Insulation System ◽  
Measurement Results ◽  
Heritage Buildings ◽  
Story Building

Internal insulation is used in many heritage buildings to ensure a better indoor environment and reduce energy use. This article describes measurement results from installing an internal insulation system in a Danish multi-story building. The internal insulation system consists of a fully glued vapour tight insulated plasterboard. To reduce the risk for wood decay and mould growth at the wooden beam ends in the floor construction, a 100-200 mm uninsulated gap was left above and below the floor construction. Measurements include the effect of orientation, degree of façade repair and influence of indoor moisture content. Results show in general acceptable hygrothermal conditions behind the insulation system. However, a gradual increase in relative humidity at sun-exposed walls was registered due to ‘summer condensation’. The degree of surface repair also showed an influence on relative humidity levels during this period. At the uninsulated gap above the floor, a higher moisture content indoor resulted in a higher relative humidity, though without exceeding the threshold for mould growth. However, a large temperature range was registered. The influence of the uninsulated gap on reducing the risk of wood decay and mould growth at the beam ends could therefore not unambiguously be confirmed.

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