scholarly journals A new method to compute mechanical properties of a standing skyline for cable yarding

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0256374
Author(s):  
Christian Knobloch ◽  
Leo Gallus Bont

Cable-based technologies are the backbone for logistics of timber or construction material on impassable terrain. In Central Europe, the use of standing skylines with pre-stressed, both-sided fixed-anchor cables and multi-span configurations with internal intermediate supports is common. To ensure a safe and cost-effective set-up for cable road operations, it is essential to identify and compute the properties of the skyline (e.g. load path, tensile forces). This task is challenging because it requires dealing with the non‐linear behaviour of the cable structure under the load and has to include all significant physical effects. Several approaches have previously been proposed as practical solutions, however not all physical effects were covered by those approaches, such as the inclination-dependent elastic prolongation of the cable or the longitudinal deflection of the sagging carriage. With our new proposed approach, we aim to close this gap of knowledge, and consider all relevant physical effects. We present a non-linear approach that is able to compute the properties of a wide range of standing skyline configurations, including those with additional cables. This approach offers an extensive solution and a flexible framework for considering individual configurations or particularities by adding equations to the equation system.

Author(s):  
Anju Gupta ◽  
R K Bathla

With so many people now wearing mobile devices with sensors (such as smartphones), utilizing the immense capabilities of these business mobility goods has become a prospective skill to significant behavioural and ecological sensors. A potential challenge for pervasive context assessment is opportunistic sensing, has been effectively used to a wide range of applications. The sensor cloud combines cloud technology with a wireless sensor, resulting in a scalable and cost-effective computing platform for real-time applications. Because the sensor's battery power is limited and the data centre’s servers consume a significant amount of energy to supply storage, a sensor cloud must be energy efficient. This study provides a Fog-based semantic for enabling these kinds of technologies quickly and successfully. The suggested structure is comprised of fundamental algorithms to help set up and coordinate the fog sensing jobs. It creates effective multihop routes for coordinating relevant devices and transporting acquired sensory data to fog sinks. It was claimed that energy-efficient sensor cloud approaches were categorized into different groups and that each technology was examined using numerous characteristics. The outcomes of a series of thorough test simulation in NS3 to define the practicality of the created console, as well as the proportion of each parameter utilized for each technology, are computed.


2011 ◽  
Vol 147 ◽  
pp. 112-116
Author(s):  
Zhi Hong Ran ◽  
Jun Tong Qu ◽  
Fei He ◽  
Sheng Miao

In order to solve the difficult in calculating cable vibration, the non-linear dynamic model of cable was set up with geometrical non-linearity. The differential equation was solved using the singular perturbation method. The analytical expression of frequency and form function was deduced. The expression can be widely used for the field of measurement of cable force and identification of parameter in cable structure.


1996 ◽  
Vol 32 (4) ◽  
pp. 405-418
Author(s):  
X. Bonneau

SUMMARYOver several decades agronomists have developed a mineral nutrition management method for perennial oil crops based on leaf analysis combined with reference field trials. This method has been used in a coconut plantation on the peats of the east coast of Sumatra to optimize mineral nutrition in a very short time, at minimum cost and with maximum reliability, through successive adjustments of the fertilizer schedules. Two reference trials were set up to study a wide range of mineral nutrients assumed to be deficient on this area. Further experiments were set up as new nutritional problems occurred at the plantation, and as soon as the first results were obtained from these two trials. In this way, the iron and copper deficiency problems at the plantation were dealt with satisfactorily taking an experimental approach. New experiments were set up recently to test the hypothesis of a silicon deficiency. The fertilization schedules for the commercial plantation were developed by successive adjustments based on the trial results. Leaf analysis data showed that the coconut palms in the commercial plots always complied with the experimental models. In addition to being rapid and reliable, this method was also cost-effective, especially when larger areas were involved.


1996 ◽  
Vol 32 (4) ◽  
pp. 405-418
Author(s):  
X. Bonneau

SUMMARYOver several decades agronomists have developed a mineral nutrition management method for perennial oil crops based on leaf analysis combined with reference field trials. This method has been used in a coconut plantation on the peats of the east coast of Sumatra to optimize mineral nutrition in a very short time, at minimum cost and with maximum reliability, through successive adjustments of the fertilizer schedules. Two reference trials were set up to study a wide range of mineral nutrients assumed to be deficient on this area. Further experiments were set up as new nutritional problems occurred at the plantation, and as soon as the first results were obtained from these two trials. In this way, the iron and copper deficiency problems at the plantation were dealt with satisfactorily taking an experimental approach. New experiments were set up recently to test the hypothesis of a silicon deficiency. The fertilization schedules for the commercial plantation were developed by successive adjustments based on the trial results. Leaf analysis data showed that the coconut palms in the commercial plots always complied with the experimental models. In addition to being rapid and reliable, this method was also cost-effective, especially when larger areas were involved.


1970 ◽  
Vol 44 (2) ◽  
pp. 157-162 ◽  
Author(s):  
KN Farooque ◽  
M Zaman ◽  
E Halim ◽  
S Islam ◽  
M Hossain ◽  
...  

The characterization of Rice Husk Ash (RHA) was carried out using conventional chemical analysis and instrumental techniques. Chemical analysis reveals that RHA contains mainly silica along with minor inorganic oxides. Phase analysis by X-ray diffraction (XRD) indicates the presence of quartz, crystobalite and anorthite, while micro structural features obtained from Scanning Electron Microscopy (SEM) shows that RHA particles are highly porous and honeycombed structure. Thermal analysis indicates the presence of surface moisture. A wide range of particles (0.001-0.100 mm) are present in the sample with 59% below the size of 0.05 mm. However after characterization, utilization of RHA as a potential cost effective ingredient in developing a variety of construction materials (e.g. building brick, insulating brick and pozzolana cement) have been examined. The results obtained are very promising. Keywords : Charcterization, Rice husk ash, XRD, SEM, Construction material.   DOI: 10.3329/bjsir.v44i2.3666 Bangladesh J. Sci. Ind. Res. 44(2), 157-162, 2009


2011 ◽  
Vol 255-260 ◽  
pp. 1252-1255
Author(s):  
Zhen Yu Zhong

Dynamics response of suspended cable structure is studied in this paper. It is difficult to analyze this type of structure because of non-linear behavior. VFIFE is an efficient method to solve non-linear problems and applied to calculate movement of cable on wide range. Some results are obtained from time history of cable vibration, such as galloping and characteristic frequency. A case of cable movement under wind shows that low frequency in wind speed is main fact impacting on wave of cable.


2020 ◽  
pp. 1192-1198
Author(s):  
M.S. Mohammad ◽  
Tibebe Tesfaye ◽  
Kim Ki-Seong

Ultrasonic thickness gauges are easy to operate and reliable, and can be used to measure a wide range of thicknesses and inspect all engineering materials. Supplementing the simple ultrasonic thickness gauges that present results in either a digital readout or as an A-scan with systems that enable correlating the measured values to their positions on the inspected surface to produce a two-dimensional (2D) thickness representation can extend their benefits and provide a cost-effective alternative to expensive advanced C-scan machines. In previous work, the authors introduced a system for the positioning and mapping of the values measured by the ultrasonic thickness gauges and flaw detectors (Tesfaye et al. 2019). The system is an alternative to the systems that use mechanical scanners, encoders, and sophisticated UT machines. It used a camera to record the probe’s movement and a projected laser grid obtained by a laser pattern generator to locate the probe on the inspected surface. In this paper, a novel system is proposed to be applied to flat surfaces, in addition to overcoming the other limitations posed due to the use of the laser projection. The proposed system uses two video cameras, one to monitor the probe’s movement on the inspected surface and the other to capture the corresponding digital readout of the thickness gauge. The acquired images of the probe’s position and thickness gauge readout are processed to plot the measured data in a 2D color-coded map. The system is meant to be simpler and more effective than the previous development.


Author(s):  
Jozefien De Bock

Historically, those societies that have the longest tradition in multicultural policies are settler societies. The question of how to deal with temporary migrants has only recently aroused their interest. In Europe, temporary migration programmes have a much longer history. In the period after WWII, a wide range of legal frameworks were set up to import temporary workers, who came to be known as guest workers. In the end, many of these ‘guests’ settled in Europe permanently. Their presence lay at the basis of European multicultural policies. However, when these policies were drafted, the former mobility of guest workers had been forgotten. This chapter will focus on this mobility of initially temporary workers, comparing the period of economic growth 1945-1974 with the years after the 1974 economic crisis. Further, it will look at the kind of policies that were developed towards guest workers in the era before multiculturalism. This way, it shows how their consideration as temporary residents had far-reaching consequences for the immigrants, their descendants and the receiving societies involved. The chapter will finish by suggesting a number of lessons from the past. If the mobility-gap between guest workers and present-day migrants is not as big as generally assumed, then the consequences of previous neglect should serve as a warning for future policy making.


2016 ◽  
Vol 3 (2) ◽  
pp. 82-93
Author(s):  
Gugulethu Shamaine Nkala ◽  
Rodreck David

Knowledge presented by Oral History (OH) is unique in that it shares the tacit perspective, thoughts, opinions and understanding of the interviewee in its primary form. While teachers, lecturers and other education specialists have at their disposal a wide range of primary, secondary and tertiary sources upon which to relate and share or impart knowledge, OH presents a rich source of information that can improve the learning and knowledge impartation experience. The uniqueness of OH is presented in the following advantages of its use: it allows one to learn about the perspectives of individuals who might not otherwise appear in the historical record; it allows one to compensate for the digital age; one can learn different kinds of information; it provides historical actors with an opportunity to tell their own stories in their own words; and it offers a rich opportunity for human interaction. This article discusses the placement of oral history in the classroom set-up by investigating its use as a source of learning material presented by the National Archives of Zimbabwe to students in the Department of Records and Archives Management at the National University of Science and Technology (NUST). Interviews and a group discussion were used to gather data from an archivist at the National Archives of Zimbabwe, lecturers and students in the Department of Records and Archives Management at NUST, respectively. These groups were approached on the usability, uniqueness and other characteristics that support this type of knowledge about OH in a tertiary learning experience. The findings indicate several qualities that reflect the richness of OH as a teaching source material in a classroom set-up. It further points to weak areas that may be addressed where the source is considered a viable strategy for knowledge sharing and learning. The researchers present a possible model that can be used to champion the use of this rich knowledge source in classroom education at this university and in similar set-ups. 


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