A generalized mat consolidation model for wood composites

Holzforschung ◽  
2008 ◽  
Vol 62 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Cheng Zhou ◽  
Chunping Dai ◽  
Gregory D. Smith
Keyword(s):  
Satisfactory Agreement ◽  
Early Stage ◽  
Wood Composites ◽  
Dominant Mechanism ◽  
Fiber Assembly ◽  
Model Predictions ◽  
Density Relationship ◽  
Consolidation Model ◽  
Relationship Of ◽  
Consolidation Behavior

Abstract A generalized model for the prediction of mat pressure-density relationship of wood-based composites was developed. Based on the compression models for fiber assembly, this model treats the composite mat structure as a system of bending units, thus making element bending the dominant mechanism during early stage of mat consolidation. The consolidation behavior of fiber, strand, and particle mats were experimentally investigated. Satisfactory agreement was found between the model predictions and experimental results. Combined with the compression model, the entire strand mat consolidation can be predicted based on the properties of the wood constituents.

scholarly journals Changes in group size during resource shifts reveal drivers of sociality across the tree of life

2020 ◽  
Author(s):  
Albert B. Kao ◽  
Amanda K. Hund ◽  
Fernando P. Santos ◽  
Jean-Gabriel Young ◽  
Deepak Bhat ◽  
...  
Keyword(s):  
Group Size ◽  
Social Benefit ◽  
Tree Of Life ◽  
Strong Indication ◽  
Evolutionary Mechanisms ◽  
Resource Abundance ◽  
Dominant Mechanism ◽  
Individual Fitness ◽  
Model Predictions ◽  
Optimal Group Size

ABSTRACTFrom biofilms to whale pods, organisms have repeatedly converged on sociality as a strategy to improve individual fitness. Yet, it remains challenging to identify the most important drivers—and by extension, the evolutionary mechanisms—of sociality for particular species. Here, we present a conceptual framework, literature review, and model demonstrating that the direction and magnitude of the response of group size to sudden resource shifts provides a strong indication of the underlying drivers of sociality. We catalog six functionally distinct mechanisms related to the acquisition of resources, and we model these mechanisms’ effects on the survival of individuals foraging in groups. We find that whether, and to what degree, optimal group size increases, decreases, or remains constant when resource abundance declines depends strongly on the dominant mechanism. Existing empirical data support our model predictions, and we demonstrate how our framework can be used to predict the dominant social benefit for particular species. Together, our framework and results show that a single easily measurable characteristic, namely, group size under different resource abundances, can illuminate the potential drivers of sociality across the tree of life.

Utilization Trends and Volume-Outcomes Relationship of Endoscopic Resection for Early Stage Esophageal Cancer

2021 ◽  
Vol Publish Ahead of Print ◽  
Author(s):  
Nicole G. Jawitz ◽  
Vignesh Raman ◽  
Oliver K. Jawitz ◽  
Rahul A. Shimpi ◽  
Richard K. Wood ◽  
...  
Keyword(s):  
Esophageal Cancer ◽  
Endoscopic Resection ◽  
Early Stage ◽  
Relationship Of

scholarly journals Relationship of Whitefly Population Build up with the Spread of TYLCV on Eight Tomato Varieties

1970 ◽  
Vol 4 (1) ◽  
pp. 67-74 ◽  
Author(s):  
AHMA Rahman ◽  
AM Akanda ◽  
AKM Ashraful Alam
Keyword(s):  
Early Stage ◽  
Tomato Yellow Leaf ◽  
Growth Stages ◽  
Whitefly Population ◽  
Key Words Prevalence ◽  
Virus Prevalence ◽  
Tomato Field ◽  
Relationship Of ◽  
Leaf Curl Virus ◽  
The Relationship

The performance of eight tomato varieties namely BARI-T1 (Manik), BARI-T2 (Ratan), BARI-T4, BARI-T5, BARI-T6 (Apurba), BARI-T7 (Chaity), BARI-T11 and BARI-T12 were evaluated in respect to prevalence and spread of TYLCV (Tomato Yellow Leaf curl Virus) in relation to whitefly population buildup in the field. Data were collected on the three growth stages of the plant namely early (transplanting to first flowering) mid (first flowering to first harvesting) and late (first harvesting to last harvesting). The virus prevalence percentage in eight tomato varieties varied depending on early, mid and late stage of infection as well as tomato varieties. It ranged from 42 to 69%. There was a poor and insignificant quadratic polynomial relationship (y = -0.0059x 2 + 0.2826x – 1.5378 & R2 = 0.0962) between temperature and whitefly population build up in tomato field. The relationship between relative humidity and whitefly population build up in the field was found significant but negatively correlated (y = - 0.0321x 2 +4.5518x – 159.44 (R2 = 0.6769). The increase of whitefly population in the field was positively correlated with the spread of TYLCV in the tomato field (y = - 0.0002x 2 + 0.0297x + 1.0626 & R2 = 0.663). The highest and lowest prevalence of TYLCV was recorded in BARI-T6 and BARI-T11, respectively. In all the varieties, virus prevalence was found higher at mid stage followed by late and early stage of infection. Key words: Prevalence, TYLCV, whitefly.

Developing a mentoring programme in the chemical industry

2019 ◽  
Vol 31 (1) ◽  
pp. 42-58 ◽  
Author(s):  
Marta Santos ◽  
Cláudia Pereira ◽  
Daniel Silva ◽  
Maria Antónia Cadilhe ◽  
Liliana Cunha
Keyword(s):  
Chemical Industry ◽  
Early Stage ◽  
Methodological Approach ◽  
Training Programme ◽  
Work Situation ◽  
Content Type ◽  
New Employees ◽  
Know How ◽  
Relationship Of ◽  
The Impact

Purpose The purpose of this paper is to analyse a programme designed to welcome and train new employees, implemented in a chemical industry, privileging the transmission of know-how as a dynamic process where learning is co-constructed in the course of the activity. Design/methodology/approach The design of the programme was based on the analysis of the work performed in real context by operators and supervisors. The data about the programme’s evaluation were collected by questionnaire, assessing the trainees’ global development and the impact of the training programme (after six months). Findings This paper involves designing, planning and implementing “4 × 4 Training”, a training programme for young trainees. Combining in-class training with an extensive component of on-the-job mentoring, the programme involved trainees, mentors and internal trainers, monitored by work psychologists. The results show both the trainees and the mentors evaluate the programme positively. The professional transmission stands out as an activity that is thought through and defined in group, assisted by a mentoring relationship of mutual learning. Practical implications When planning and developing intergenerational transmission processes, it is crucial to consider the organisational conditions, to involve from an early stage the key players of each work situation and to guarantee that the mentoring activity and the productive activity overlap coherently. Originality/value It is an innovative process to integrate trainees in the chemical industry in Portugal. The methodological approach and the findings provide a first framework that justifies the relevance of the transmission of know-how through a real work situation.

Relationship of the fourth heart sound to atrial systolic transmitral flow deceleration

1997 ◽  
Vol 272 (3) ◽  
pp. H1527-H1536 ◽  
Author(s):  
A. M. McGuire ◽  
M. T. Hagley ◽  
A. F. Hall ◽  
S. J. Kovacs
Keyword(s):  
Power Spectrum ◽  
Heart Sound ◽  
Diastolic Pressure ◽  
Closed Form Expression ◽  
High Rise ◽  
Model Predictions ◽  
Flow Deceleration ◽  
Normal Mitral Valve ◽  
Relationship Of ◽  
Atrial Systole

The fourth heart sound (S4) is thought to be due to cardiohemic vibrations, powered by deceleration of transmitral blood flow, that occur when atrial systole leads to a disproportionately high rise in ventricular end-diastolic pressure (relative to diastasis), associated with an enhanced atrial systolic blood filling volume or a stiff ventricular wall. To characterize S4 production, we modeled the cardiohemic system as a forced, damped nonlinear harmonic oscillator. The forcing term used a closed-form expression for the Doppler A-wave contour. We simultaneously recorded transthoracic phonocardiograms and Doppler A waves in subjects with and without audible S4 and compared model predictions for S4 amplitude, frequency, and power spectrum with those of the recorded S4. Excellent agreement was observed between the model-predicted amplitude, duration, timing, and power spectrum and those of the phonocardiographic S4. We conclude that, with a normal mitral valve, there should always be an oscillation of the cardiohemic system during A-wave deceleration. However, oscillations may not have high enough amplitude, frequency, or coupling to the chest wall to be clinically audible as an S4.

Sign in / Sign up

Export Citation Format

Share Document