Search results for "WOOD"

Adaptive Low Priority Packet Marking for Better TCP Performance

2003

This paper proposes a packet marking scheme for TCP traffic. Unlike previous literature work, in our scheme the majority of TCP packets are transmitted as high priority. The role of a low priority packet appears that of a probe, whose goal is to early discover network congestion conditions. Low priority packets are marked according to an adaptive marking algorithm. Numerical results show that our scheme provides improved throughput/delay performance.

TCP Performance in Mobile Ad hoc Networks

2013

International audience; In this paper, we present a survey of TCP (Transmission Control Protocol) protocol for better performance in the MANET (Mobile Ad Hoc Network). After a short presentation of the main features of TCP, we give the most important problems from which TCP suffer in MANET. We present after that some approaches proposed in the literature in order to improve its performance. Our paper contains also a performance evaluation of TCP NewReno and TCP Vegas transport protocols under AODV and DSR routing protocols. The simulations are conducted under varying conditions of number of TCP connections, number of nodes and mobility.

EPR surveys on modern and ancient woods.

2007

Effetto del sistema di allevamento e della tecnologia di caseificazione sulla qualità del caciocavallo palermitano.

2011

Effects of livestock system and cheese making technique on the quality of Caciocavallo Palermitano cheese - Caciocavallo Palermitano is a typical stretched curd cheese produced in the Central and Western Sicily. It is traditionally obtained from whole milk of indigenous cows breeds and by the original cheese making technology in which wooden tools, source of inoculum of autochthonous lactic bacteria, are used. Recently, Caciocavallo Palermitano cheese is also obtained in dairy intensive farms of specialized breeds where milk is processed mainly using stainless steel equipment and commercial selected lactic ferments. The aim of this investigation was to verify the influence of cheese making …

DSC AND TGA TO EVALUATE THE SELECTIVE IMPREGNATION OF WATERLOGGED ARCHAEOLOGICAL WOODS WITH POLY(ETHYLENE) GLYCOLS MIXTURES

2012

Within the cultural heritage field the wood conservation of waterlogged archaeological objects aims at preventing the collapsing of the wooden structure (upon drying) the degradation of which is related to the Taxon but also to the chemical and biological nature of the site. The refilling of the wood cavities with a consolidant, which confers robustness and stability, is an interesting strategy for the conservation methods of waterlogged archaeological objects. To this purpose, using different impregnation methods, waterlogged archaeological woods were consolidated by using aqueous mixtures of poly(ethylene) glycols with different molecular weights (PEG 400 and PEG 4000) as well as mixtures…

Intrusive growth of initials does not affect cambial circumference in Robinia pseudoacacia

2021

AbstractThis study aimed to test the hypothesis whether intrusive growth of initial cells is related to the increase in circumference of Robinia pseudoacacia vascular cambium—both qualitatively and quantitatively. The mode of intrusive growth of cambial initial cells was also studied. Samples collected from tree trunks were examined using series of semi-thin transverse sections. Anatomical reconstructions of radial and tangential planes of analysed fragments of cambial tissue were made. Observations and measurements have shown that the intrusive growth of R. pseudoacacia initial cells does not contribute to an increase in tangential dimension of observed tissue fragments where cell rearrang…

Unmanned aerial system imagery and photogrammetric canopy height data in area-based estimation of forest variables

2015

In this paper we examine the feasibility of data from unmanned aerial vehicle (UAV)-borne aerial imagery in stand-level forest inventory. As airborne sensor platforms, UAVs offer advantages cost and flexibility over traditional manned aircraft in forest remote sensing applications in small areas, but they lack range and endurance in larger areas. On the other hand, advances in the processing of digital stereo photography make it possible to produce three-dimensional (3D) forest canopy data on the basis of images acquired using simple lightweight digital camera sensors. In this study, an aerial image orthomosaic and 3D photogrammetric canopy height data were derived from the images acquired …

A comparative economic analysis of torrefied pellet production based on state-of-the-art pellets

2017

Abstract Torrefied pellets have fuel properties superior to those of conventional wood pellets and potentially allow greater rates of co-firing and thus larger reductions in net CO 2 emissions. Despite the growing amount of scientific output on torrefaction, the economic feasibility of torrefied pellet production is still a topic of considerable uncertainty. This is an obstacle for decision makers looking to implement sustainable energy policies. This paper compares the economics of torrefied pellets to conventional wood pellets. Working backwards from demonstrated pellet properties, this work attempts to answer the following question: Based on state-of-the-art torrefied pellets, what would…

Comparison of δ(13)C and δ(18)O from cellulose, whole wood, and resin-free whole wood from an old high elevation Pinus uncinata in the Spanish centra…

2016

δ(13)C and δ(18)O values from sapwood of a single Pinus uncinata tree, from a high elevation site in the Spanish Pyrenees, were determined to evaluate the differences between whole wood and resin-free whole wood. This issue is addressed for the first time with P. uncinata over a 38-year long period. Results are also compared with published isotope values of α-cellulose samples from the same tree. The differences in δ(13)C and δ(18)O between whole wood and resin-free whole wood vary within the analytical uncertainty of 0.3 and 0.5 ‰, respectively, indicating that resin extraction is not necessary for sapwood of P. uncinata. Mean differences between cellulose and whole wood are 0.9 ‰ (δ(13)C)…

Comparative biochemistry of CO2 fixation and the evolution of autotrophy

1999

Carbon dioxide fixation is a polyphyletic trait that has evolved in widely separated prokaryotic branches. The three principal CO2-assimilation pathways are (i) the reductive pentose-phosphate cycle, i. e. the Calvin-Benson cycle; (ii) the reductive citric acid (or Arnon) cycle; and (iii) the net synthesis of acetyl-CoA from CO/CO2, or Wood pathway. Sequence analysis and the comparative biochemistry of these routes suggest that all of them were shaped to a considerable extent by the evolutionary recruitment of enzymes. Molecular phylogenetic trees show that the Calvin-Benson cycle was a relatively late development in the (eu)bacterial branch, suggesting that some form(s) of carbon assimilat…