scholarly journals Productivity of a Portable Winch System Used in Salvage Logging of Storm-Damaged Timber

2019 ◽  
Vol 40 (2) ◽  
pp. 311-318
Author(s):  
Ebru Bilici ◽  
Güryay Volkan Andiç ◽  
Abdullah Emin Akay ◽  
John Sessions

Storm damages result in serious losses in many regions, primarily by stem breakage or blowdown. Extraction of storm-damaged trees often requires more difficult than normal skidding activities due to obstacles created during the storm. In this study, the productivity of a portable winch was evaluated as a possible alternative to recover storm-damaged timber. Field measurements were conducted in the Alabarda Forest Enterprise Chief located near the city of Kütahya in western Turkey, where storm damage often occurs during the winter season. The time study was implemented in two slope classes (35% and 55%) and two skidding distances (40 m and 60 m). All timber was skidded uphill. A regression mode was developed that related productivity to log volume, ground slope and skidding distance. The highest percentage of total cycle time was observed for skidding logs to the landing. The highest productivity (3.96 m3/hour) was found at the shorter skidding distance (40 m) and the lower ground slope (35%). Statistical analyses indicated that productivity was most highly affected by log volume, followed by skidding distance and ground slope. Larger log loads increased productivity, while both longer skidding distances and steeper slopes reduced productivity.

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 309
Author(s):  
Stanimir Stoilov ◽  
Andrea R. Proto ◽  
Georgi Angelov ◽  
Salvatore F. Papandrea ◽  
Stelian Alexandru Borz

Steep terrain harvesting can only be implemented by a limited set of operational alternatives; therefore, it is important to be efficient in such conditions, in order to avoid incurring high costs. Harvesting abiotically-disturbed forests (salvage harvests caused by wet snow), which is becoming common these days, can significantly impact the operational efficiency of extraction operations. This study was implemented in order to evaluate the performance of truck-mounted uphill cable yarding operations in salvage logging deployed in coniferous stands. A time study was used to estimate the productivity and yarding costs, and predictive models were developed in order to relate the time consumption and productivity to the relevant operational factors, including the degree of wood damage. The average operational conditions were characterized by an extraction distance of 101 m and a lateral yarding distance of 18 m, resulting in a productivity rate of 20.1 m3 h−1. In response to different kind of delays, the productivity rate decreased to 12.8 m3 h−1. Under the prevailing conditions, lateral yarding accounted for 32% of the gross work cycle time, and for 50% of the delay-free work cycle time of the machine. Decreasing the lateral yarding distance and increasing the payload volume to the maximum capacity of the machine would eventually lead to a yarding productivity of close to 30 m3 per SMH (scheduled machine hour). The calculation of the gross costs of uphill yarding showed that the labor costs (35.7%) were slightly higher than the fixed costs (32.9%), and twice as high compared to the variable costs (17.7%). The remote control of the carriage, mechanical slack-pulling mechanisms, and radio-controlled chokers are just some of the improvements that would have led to increments in operational efficiency.


2014 ◽  
Vol 660 ◽  
pp. 971-975 ◽  
Author(s):  
Mohd Norzaim bin Che Ani ◽  
Siti Aisyah Binti Abdul Hamid

Time study is the process of observation which concerned with the determination of the amount of time required to perform a unit of work involves of internal, external and machine time elements. Originally, time study was first starting to be used in Europe since 1760s in manufacturing fields. It is the flexible technique in lean manufacturing and suitable for a wide range of situations. Time study approach that enable of reducing or minimizing ‘non-value added activities’ in the process cycle time which contribute to bottleneck time. The impact on improving process cycle time for organization that it was increasing the productivity and reduce cost. This project paper focusing on time study at selected processes with bottleneck time and identify the possible root cause which was contribute to high time required to perform a unit of work.


2010 ◽  
Vol 10 (12) ◽  
pp. 30205-30277 ◽  
Author(s):  
M. Shrivastava ◽  
J. Fast ◽  
R. Easter ◽  
W. I. Gustafson ◽  
R. A. Zaveri ◽  
...  

Abstract. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is modified to include a volatility basis set (VBS) treatment of secondary organic aerosol formation. The VBS approach, coupled with SAPRC-99 gas-phase chemistry mechanism, is used to model gas-particle partitioning and multiple generations of gas-phase oxidation of organic vapors. In addition to the detailed 9-species VBS, a simplified mechanism using 2 volatility species (2-species VBS) is developed and tested for similarity to the 9-species VBS in terms of both mass and oxygen-to-carbon ratios of organic aerosols in the atmosphere. WRF-Chem results are evaluated against field measurements of organic aerosols collected during the MILAGRO 2006 campaign in the vicinity of Mexico City. The simplified 2-species mechanism reduces the computational cost by a factor of 2 as compared to 9-species VBS. Both ground site and aircraft measurements suggest that the 9-species and 2-species VBS predictions of total organic aerosol mass as well as individual organic aerosol components including primary, secondary, and biomass burning are comparable in magnitude. In addition, oxygen-to-carbon ratio predictions from both approaches agree within 25%, providing evidence that the 2-species VBS is well suited to represent the complex evolution of organic aerosols. Model sensitivity to amount of anthropogenic semi-volatile and intermediate volatility (S/IVOC) precursor emissions is also examined by doubling the default emissions. Both the emission cases significantly under-predict primary organic aerosols in the city center and along aircraft flight transects. Secondary organic aerosols are predicted reasonably well along flight tracks surrounding the city, but are consistently over-predicted downwind of the city. Also, oxygen-to-carbon ratio predictions are significantly improved compared to prior studies by adding 15% oxygen mass per generation of oxidation; however, all modeling cases still under-predict these ratios downwind as compared to measurements, suggesting a need to further improve chemistry parameterizations of secondary organic aerosol formation.


2019 ◽  
Vol 43 (1) ◽  
pp. 59-66
Author(s):  
Mohammad Lokman Hossain ◽  
Subrata Chandra Roy ◽  
Mithun Chandra Bepari ◽  
Bilkis Ara Begum

Air borne particulate matter PM10 and PM2.5 were collected by using Mini Vol portable Air Sampler from the world most densely populated city Dhaka and its suburban areas over a period of January through December in 2016. This study revealed a comparison of atmospheric particulate matter (PM) of a highly polluted urban area to its two neighboring areas that accommodate heavy oil based power plants. In all three sites the quantity of PM decreases in summer reaching its lowest level in the month of July, however, it increases significantly in winter season. Despite the presence of the fuel based power plants the average concentrations of PM10 and PM2.5 at the city Dhaka surpasses its two neighbors Manikganj and Nawabganj. Interestingly, PM2.5/PM10 ratio is higher at the suburban areas than urban area. The study shows that for all the sites PM2.5 is approximately twice than that of WHO and USEPA. However, the values of PM2.5 is almost similar for Nawabganj and Manikganj but much higher for the Dhaka city especially during dry season . The Mass concentration of Black Carbon (BC) was also determined from the PM samples from Manikganj and Nawabganj. Journal of Bangladesh Academy of Sciences, Vol. 43, No. 1, 59-66, 2019


2011 ◽  
Vol 11 (13) ◽  
pp. 6639-6662 ◽  
Author(s):  
M. Shrivastava ◽  
J. Fast ◽  
R. Easter ◽  
W. I. Gustafson ◽  
R. A. Zaveri ◽  
...  

Abstract. The Weather Research and Forecasting model coupled with chemistry (WRF-Chem) is modified to include a volatility basis set (VBS) treatment of secondary organic aerosol formation. The VBS approach, coupled with SAPRC-99 gas-phase chemistry mechanism, is used to model gas-particle partitioning and multiple generations of gas-phase oxidation of organic vapors. In addition to the detailed 9-species VBS, a simplified mechanism using 2 volatility species (2-species VBS) is developed and tested for similarity to the 9-species VBS in terms of both mass and oxygen-to-carbon ratios of organic aerosols in the atmosphere. WRF-Chem results are evaluated against field measurements of organic aerosols collected during the MILAGRO 2006 campaign in the vicinity of Mexico City. The simplified 2-species mechanism reduces the computational cost by a factor of 2 as compared to 9-species VBS. Both ground site and aircraft measurements suggest that the 9-species and 2-species VBS predictions of total organic aerosol mass as well as individual organic aerosol components including primary, secondary, and biomass burning are comparable in magnitude. In addition, oxygen-to-carbon ratio predictions from both approaches agree within 25 %, providing evidence that the 2-species VBS is well suited to represent the complex evolution of organic aerosols. Model sensitivity to amount of anthropogenic semi-volatile and intermediate volatility (S/IVOC) precursor emissions is also examined by doubling the default emissions. Both the emission cases significantly under-predict primary organic aerosols in the city center and along aircraft flight transects. Secondary organic aerosols are predicted reasonably well along flight tracks surrounding the city, but are consistently over-predicted downwind of the city. Also, oxygen-to-carbon ratio predictions are significantly improved compared to prior studies by adding 15 % oxygen mass per generation of oxidation; however, all modeling cases still under-predict these ratios downwind as compared to measurements, suggesting a need to further improve chemistry parameterizations of secondary organic aerosol formation.


Tahiti ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Marie-Sofie Lundström

In 1931, the Finnish painter Juho Rissanen (1873-1950) travelled to the tourist city Biskra in Algeria, then spending there the winter season, a most agreeable time in North Africa. It is situated on the verge of the Saharan desert, and ever since Algeria had become a French colony in the early nineteenth century, the city hosted hordes of tourists. (Algeria became independent as late as in 1962.) Biskra was known for its sulphate baths, which were supposed to improve health. But as several travellers and painters have observed, it was also the perfect spot where to hire a camel and a driver for a journey into an unwelcoming desert. Algerian Sahara had in fact been the target of many earlier nineteenth century Orientalists, and the country’s status as a French colony made its sights relatively accessible to foreigners. Rissanen was one of those following in the footsteps of earlier itinerants. The authenticity of the city as the visitors saw it is, however, a complex question. The travellers usually lived at the same hotel near the baths and stayed mostly in the company of each other. The locals in their turn – a travel account of the time explains – were always ready to pose wherever a Kodak camera would turn up, and as a result, costume studies were produced and camels painted. All foreigners regarded camel excursion as the climax of the stay. In Finland, Rissanen is best known for his late nineteenth- and early twentieth century portraits of Finnish rural types, let be that he later turned to other motifs and techniques. Even today, the latter part of his production is much lesser known than the celebrated highlights. Chronic anxiety about health constantly led the painter to warmer climates; he spent his final years in Florida after having sauntered around the Mediterranean, e.g. Southern France, in the interwar years.  The aim of my article is threefold: firstly, to investigate Rissanen’s motifs for travelling to Biskra; secondly, to show that Rissanen’s encounter with the city was purely touristic, in line with its reputation as a travel destination in colonial France; and thirdly, to present its outcome as an example of late Orientalist painting. To sum up, I consider the reception of Rissanen’s later art production, in order to situate his Biskra-pictures within a larger context.  Unfortunately, I have, so far, only been able to locate a handful of watercolours now belonging to Kuopio Art Museum. The Kuopio collection also contains Rissanen’s letters to his friend, the physician Emil Suihko, as well as to the art historian Onni Okkonen, among others. In his correspondence, Rissanen lingers on Biskra. The works I have found depict craftsmen sitting in the streets and women wearing colourful, local dresses. Needless to say, even Rissanen proved his love of the desert by drawing camels. It is another matter that these ubiquitous animals of course could be spotted in the streets, too. Interestingly, in an interview made shortly after Biskra and published in a 1931 issue of the Finnish magazine Konstrevyn, Rissanen says very little of why and how he painted in Northern Africa. Virtually, the whole text deals with touristic trivia. Keywords: Juho Rissanen (1873-1950), Biskra, French Orientalism, tourism, 20th century visual arts 


2018 ◽  
Vol 12 (2) ◽  
pp. 155-165
Author(s):  
Iustina Lateș ◽  
Alexandru-Lucian Luca ◽  
Ștefania Chirica ◽  
Mihail Luca

Abstract The work involves the realization of a GIS model that includes both information on real estate cadastre and water supply networks. This shows the stages of making such a model, starting from field measurements, to structuring the database and custom layouts. In the study, the distribution pipelines equipped with fire hydrants and the existing building types in the area were considered as the main elements. Buildings were classified according to importance, height, destination, mapping indexes, etc. and have been integrated into the GIS model. GIS programs aim at specifying as much as possible the textual data attached to perform complex analyzes. Autocad and ArcMap programs allow you to get thematic maps on building types, pipeline network analysis on which hydrants are located, and how to protect firewalls. The study model was developed only for a sector in the city of Iaşi, but it can be extended to an application that can be used in other urban areas for the purpose of being used by the water-channel directorate, the intervention teams, the public administration local, etc.


2011 ◽  
Vol 11 (1) ◽  
pp. 33-44 ◽  
Author(s):  
Maksymilian Solarski ◽  
Alicja Pradela ◽  
Mariusz Rzętała

Natural and anthropogenic influences on ice formation on various water bodies of the Silesian Upland (southern Poland)The aim of the study was to identify patterns of ice-related phenomena on 39 selected anthropogenic water bodies in the Silesian Upland in southern Poland. The core research was conducted in the winter season of 2009/2010, between December and March. Field measurements and observations were conducted every two days during the freezing and thawing phases and every four days at the time of continuous ice cover. Data were interpolated to cover days without observations. Differences in the ice cover phenology on these water bodies were caused by natural conditions (morphometric and hydro-meteorological) and human activity (thermal pollution). Two principal groups of anthropogenic water bodies were identified in terms of the ice phenomena: lakes and ponds with a natural or quasi-natural pattern of ice phenomena and water bodies featuring various degrees of human impact. The thickness of the ice-cover was found to vary, which was a source of great danger to the users of the water bodies in the winter season.


2018 ◽  
Vol 7 (4) ◽  
pp. 87
Author(s):  
Baran R. Omer ◽  
Sherzad W. Khalid

Nowadays, number of cars increases in Iraqi Kurdistan. Duhok is one of the Iraqi Kurdistan cities where an enormous increase in the number of cars and population is noticed during the last decade. Roads were been mended according to the 1970s plans where the city was small and number of cars was few. Although the city geographically is located in a hilly area and between two mountains, mending roads is a problem of area. Roads in the mentioned city are quite busy due to the high number of cars, traffic jams can be noticed in every corner of the city especially in signalized intersections. The level of service (LOS) in most of the signalized intersections is F or E. in order to lower the high (LOS), a three leg signalized intersection has been chosen to do an improvement on. During the study the number of the cars (Volume) have been enumerated in all lane groups and the results showed that the (LOS) was E in the intersection. As a result, some solutions have been provided according to the site area and the traffic flow. Solutions were geometric changes, cycle time changes or combination in both geometric and cycle time changes. According to the collected data, it was found that level of service was E for WB and SB and for EB was D. Based on data analysis it was found that LOS has not been improved when only one of the mentioned solutions is applied. In order to have the best improvement, the combination between geometric and cycle time length changes are applied. Analysis showed that there was a remarkable improvement in LOS and changed from E to D.


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