scholarly journals The Impact of Season on Productivity and Time Consumption in Timber Harvesting from Young Alder Stands in Lowland Poland

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1081
Author(s):  
Witold Grzywiński ◽  
Rafał Turowski ◽  
Bartłomiej Naskrent ◽  
Tomasz Jelonek ◽  
Arkadiusz Tomczak
Keyword(s):  
Alnus Glutinosa ◽  
Timber Harvesting ◽  
Working Time ◽  
Time Consumption ◽  
Ne Poland ◽  
Forest Division ◽  
Loading And Unloading ◽  
The Impact ◽  
Thinning Process ◽  
Labour Time

The purpose of this study was to establish the impact of season on productivity, labour consumption, and working time structure during timber harvesting from young alder stands (Alnus glutinosa Gaertn.). An early thinning process was performed in summer and winter in pure alder stands (38 and 40 years old) in the Płaska Forest Division (NE Poland). The felling and processing operations were performed by experienced loggers using the cut-to-length (CTL) system, and forwarding with manual loading and unloading involved the use of a Zetor 7045 (65 HP) farming tractor and trailer. In both summer and winter, the loggers spent most of their labour time on felling trees (approx. 23%) and bucking (approx. 36%). Assistant loggers spent most of their time stacking logs (49.2% in summer and 58% in winter). The most time-consuming activities in forwarding were loading, unloading, and transportation. The average time consumption of tree felling and processing amounted to 0.36 ± 0.11 h/m3; that of forwarding was lower, at 0.24 ± 0.07 h/m3. No statistically significant differences in the labour consumption of tree felling were identified between winter and summer (p = 0.863). For forwarding, labour consumption was significantly higher in winter (0.28 h/m3) than in summer (0.19 h/m3, p = 0.001). Average productivity was 3.02 ± 1.09 m3/h for tree felling and 4.76 ± 1.80 m3/h for forwarding. The productivity of felling was similar in winter (2.83 m3/h) and in summer (3.22 m3/h). For forwarding, productivity was significantly higher in summer (5.70 m3/h) than in winter (3.81 m3/h, p < 0.01).

scholarly journals The Effect of Season of the Year on the Frequency and Degree of Damage during Commercial Thinning in Black Alder Stands in Poland

Forests ◽  
2019 ◽  
Vol 10 (8) ◽  
pp. 668 ◽  
Author(s):  
Witold Grzywiński ◽  
Rafał Turowski ◽  
Bartłomiej Naskrent ◽  
Tomasz Jelonek ◽  
Arkadiusz Tomczak
Keyword(s):  
Alnus Glutinosa ◽  
Timber Harvesting ◽  
Black Alder ◽  
Damage Location ◽  
Commercial Thinning ◽  
North Eastern ◽  
Thinning Operations ◽  
Loading And Unloading ◽  
Degree Of Damage ◽  
Agricultural Tractor

The aim of this study was to investigate the effect of season of the year on the frequency and degree of damage to residual trees caused during winter and summer timber harvesting operations in young alder stands. Analyses were conducted in pure black alder (Alnus glutinosa Gaertn.) stands aged 38 and 40 years, located in north-eastern Poland. Chainsaw logging was performed in the cut-to-length (CTL) system, while timber was extracted using an agricultural tractor with a trailer with manual timber loading and unloading. Damage caused in the stand as a result of early thinning operations was evaluated in terms of: (1) damage location, (2) wound size, (3) wound depth, and (4) the distance of the damaged tree from the skid trail. Timber harvesting caused damage in 8.3% of trees remaining in the stand. Both the total number of damaged trees (p = 0.001) and the number of trees damaged during felling (p = 0.01) and extraction of timber (p < 0.001) were greater in summer than in winter. Irrespective of the season, two-thirds of all cases of damage were caused during timber extraction, with 67.7% of damage recorded on trunks or root collars and 32.3% on roots. Irrespective of the season and the technological operation, slightly over 50% of cases of damage were small wounds of max. 10 cm2. The proportions of medium-sized wounds (11–100 cm2) and large wounds (over 100 cm2) were comparable. The majority of damaged trees (85.1%) were found in the vicinity (<1 m) of the skid trails. The frequency of tree damage near the skid trail was twice as large in summer as in winter (p < 0.001).

scholarly journals A Simulation Model of Construction Projects Executed in Random Conditions with the Overlapping Construction Works

2021 ◽  
Vol 13 (11) ◽  
pp. 5795
Author(s):  
Sławomir Biruk ◽  
Łukasz Rzepecki
Keyword(s):  
Simulation Model ◽  
Technological Process ◽  
Construction Projects ◽  
Working Time ◽  
Simulation Studies ◽  
Construction Methods ◽  
The Impact ◽  
Construction Works

Reducing the duration of construction works requires additional organizational measures, such as selecting construction methods that assure a shorter realization time, engaging additional resources, working overtime, or allowing construction works to be performed simultaneously in the same working units. The simultaneous work of crews may affect the quality of works and the efficiency of construction processes. This article presents a simulation model aimed at assessing the impact of the overlap period on the extension of the working time of the crews and the reduction of a repetitive project’s duration in random conditions. The purpose of simulation studies is to provide construction managers with guidelines when deciding on the dates of starting the sequential technological process lines realized by specialized working crews, for sustainable scheduling and organization of construction projects.

scholarly journals Standardization of complementary work time in timber harvesting processes

2020 ◽  
Vol 62 (4) ◽  
pp. 258-269
Author(s):  
Krzysztof Kamiński ◽  
Grzegorz Szewczyk ◽  
Janusz Kocel
Keyword(s):  
Accurate Determination ◽  
Timber Harvesting ◽  
Time Structure ◽  
Working Environment ◽  
Work Time ◽  
Work Shift ◽  
Machine Technology ◽  
Working Day ◽  
Technology Level ◽  
The Impact

AbstractOne of the essential elements of work technology assessment is task performance time. In the working day structure, production times are crucial; however, under certain conditions, complementary work times can have a share of up to 30%. Accurate determination of the time structure of a work shift is very time consuming and requires time measurements using the methods of cumulative timing or snapshot observations. For this reason, the overall share of complementary work times in a work shift is usually estimated roughly, equally for all timber harvesting conditions. The aim of this study was to determine the impact of selected working environment factors on the share of complementary work times in a work shift, in technologies on the manual-machine and the machine levels. The analyses were carried out in 33 forest districts of the Regional Directorate of State Forests in Wrocław. Among forest contractors, surveys were carried out to analyse the time structure of a working day. For each forest district, analyses of environmental factors potentially relevant to the share of complementary work times in a work shift were carried out; these included field features, dispersion of stands, features of timber, area accessibility. The total share of complementary work times in the machine-level technology variant amounted to approx. 40% and was higher than the manual-machine technological variant, where this share amounted to approx. 35%. The models developed for standardization of the share of variability of complementary work times, in the case of the manual-machine technology level, took into account the share of timber assortments with the length of over 2.5 m as well as the share of upland and mountain sites. In the case of timber harvesting at the machine technology level, the standardization model included as significant the factors such as the share of coniferous forest sites, the number of forest complexes with an area of over 100 hectares, and the total length of roads. Therefore, the above features could be selected as decisive for the share of the complementary work time category out of the full set of environmental variables taken into consideration in the estimation of the time-consumption of timber harvesting processes.

scholarly journals The Moving of Seaport from Labuhan Deli to Belawan in the Period of 1863-1942

2020 ◽  
Vol 3 (4) ◽  
pp. 3308-3313
Author(s):  
Suprayitno Suprayitno ◽  
Ratna Ratna ◽  
Rohani Rohani ◽  
Ganie Ganie ◽  
Handoko Handoko
Keyword(s):  
Economic Condition ◽  
Maritime History ◽  
Dutch Government ◽  
Historical Method ◽  
Research Problems ◽  
Loading And Unloading ◽  
Colonial Government ◽  
The Impact ◽  
Sea Coast ◽  
Dutch Colonial

Plantation economic growth has the impact on development in various aspects. One of them is shipping and trade development. Before the existence of plantations in East Sumatera, shipping and trade in Medan were centered at Labuhan Deli as a river-port. Since big ships could not sail on the river, it was considered not effective and efficient anymore. Therefore, the Dutch   Colonial Government planned to build a seaport located on the sea coast so that loading and unloading would be easy to do, and they selected Belawan to be the new seaport. The research problems were how about the existence of Labuhan Deli by the policy of the Dutch Government on moving the seaport to Belawan and what was their reason for it, and how about shipping and trade business in Belawan. This research used archives and other writing materials from the period of the Dutch Colonial Government in Medan and used historical method. The objective of the research was to find out whether plantation economic condition could change various aspects, including shipping and trade at the time. The result of this research was expected to become the reference for the writing on advanced maritime history, particularly on seaport. 

scholarly journals On the improved thinning risk model under a periodic dividend barrier strategy

2021 ◽  
Vol 6 (12) ◽  
pp. 13448-13458
Author(s):  
Fuyun Sun ◽  
◽  
Yuelei Li ◽  
Keyword(s):  
Integral Equations ◽  
Counting Process ◽  
Risk Model ◽  
Insurance Companies ◽  
Barrier Strategy ◽  
Improved Model ◽  
The Impact ◽  
Thinning Process ◽  
Explicit Expressions

<abstract><p>In this study, we consider a periodic dividend barrier strategy in an improved thinning risk model, which indicates that insurance companies randomly receive premiums and pay dividends. In the improved model, the premium is stochastic, and the claim counting process is a p-thinning process of the premium counting process. The integral equations satisfied by the Gerber-Shiu function and the expected discounted cumulative dividend function are derived. Explicit expressions of those actuarial functions are obtained when the claim and premium sizes are exponentially distributed. We analyze and illustrate the impact of various parameters on them and obtain the optimal barrier. Finally, a conclusion is drawn.</p></abstract>

scholarly journals The Impact of Timber Harvesting Guidelines and Timber Sale Attributes on Stumpage Bidding Behavior

2005 ◽  
Vol 22 (4) ◽  
pp. 275-280 ◽  
Author(s):  
Michael A. Kilgore ◽  
Charles R. Blinn
Keyword(s):  
Forest Management ◽  
Timber Harvesting ◽  
Physical Characteristics ◽  
The Other ◽  
Sources Of Information ◽  
Bidding Behavior ◽  
Specific Factors ◽  
Timber Sale ◽  
The Cost ◽  
The Impact

Abstract Twenty-seven public timber tracts were auctioned in Minnesota where bidders were required to submit two sealed bids for a tract–one with and the other without the use of timber harvesting guidelines. After the auctions, bidders were mailed a questionnaire requesting information about their logging business, the sources of information consulted in developing their bids, and perceptions of how various tract- and sale-specific factors and guidelines influenced their bidding behavior. The majority of responding timber harvesters did not consult any special sources and only one-half visited the tract before submitting their bids. Although bidding behavior was influenced by several factors, a tract's physical characteristics (e.g., volume of merchantable timber) had a greater influence on their bidding behavior than did any guidelines. Of the guidelines evaluated, those that required leaving merchantable trees (e.g., for wildlife or visual purposes) were reported to have the greatest influence on stumpage bids. Sale-specific variables (e.g., timber harvester's need for timber) had only a minimal to moderate influence on bidding behavior. The findings suggest that timber sale design can help mitigate the cost associated with implementing forest management guidelines.North. J. Appl. For. 22(4):275–280.

The Impact of Different Rosters on Employee Work and Non-Work

2003 ◽  
Vol 12 (2-3) ◽  
pp. 315-332 ◽  
Author(s):  
Angela Baker ◽  
Gregory Roach ◽  
Sally Ferguson ◽  
Drew Dawson
Keyword(s):  
Working Time ◽  
Night Work ◽  
Work Time ◽  
Social Time ◽  
Potential Impact ◽  
The Impact

Australian organizations are extending the 8-hour shift in response to market demands. The aim of this study was to quantify the impact of working time arrangements on employees who work shiftwork. A survey was developed to investigate preferred work and non-work time and to determine the potential impact of two rosters (mining and transport). A total of 256 shiftworkers working either 8-or 12-hour shifts were matched on age, gender, marital and parenting status. Both groups placed higher value on work time during the day, Monday to Friday and preferred weekend work to night work. Furthermore, the two imposed rosters suggest that the benefits cited concerning 12-hour rosters and social time are more a reduction in the loss of preferred time than an absolute gain.

scholarly journals Experimental Study on the Effect of Advancing Speed and Stoping Time on the Energy Release of Overburden in an Upward Mining Coal Working Face with a Hard Roof

2019 ◽  
Vol 12 (1) ◽  
pp. 37 ◽  
Author(s):  
Feng Cui ◽  
Yanbin Yang ◽  
Xingping Lai ◽  
Chong Jia ◽  
Pengfei Shan
Keyword(s):  
Coal Seam ◽  
Energy Release ◽  
Rock Burst ◽  
Response Ratio ◽  
Working Face ◽  
Significant Difference ◽  
Loading And Unloading ◽  
Microseismic Events ◽  
Microseismic Event ◽  
The Impact

In order to study the influence of advancing speed and stoping time of a coal face on the scale and frequency of rock burst, the energy release characteristics of an overburden fracture under six advancing speeds and four stoping times are studied by theoretical analysis and similar simulation experiments. The distribution characteristics of microseismic events before and after stoppage are compared, and the load/unload response ratio is introduced to analyze the relationship between the synergistic effect of advancing speed and stoping time and the characteristics of microseismic events in coal and rock mass. The mechanism of rock burst induced by the advancing speed and stoping time effect in the working face is studied, and the coordinated regulation and mitigation of advancing speed and stoping time are analyzed and completed. The results show that the effect of advancement speed and stoping time is very important to the energy release of overburden. The energy released by microseismic events during stoping is exponentially related to the advancing speed. The change of advancing speed causes the change of microseismic event characteristics, reflecting the evolution process of overburden structure and its energy. During stoping, the secondary microseismic events disturbed by mining occur frequently, leading to the significant difference of energy released by microseismic events during stoping. After stoping, the microseismic energy is more than four times higher than that during the stop period, and the risk of coal seam impact is high during the stope period. The synergetic change of advancement speed and stoping time changes the cycle of energy accumulation and release. The response ratio of loading and unloading considering the effect of advancement speed and stoping time is established by using the corresponding ratio of loading and unloading, and the impact risk of the coal seam is quantitatively analyzed. Based on the monitoring and analysis of microseismic events, the safety mining index of coordinated control with the energy of a single microseismic event of 180 J is established, and the best advancing speed of the working face is determined to be 4 m/d. According to the corresponding ratio of loading and unloading, the reasonable stoping time of different advancing speeds and the corresponding advancing speed of different stoping times after the resumption of mining are determined, so as to provide a reference for the safe and efficient mining of similar rock burst mines.

scholarly journals The impact of physical illness and the European working time directives

2004 ◽  
Vol 28 (5) ◽  
pp. 183-183
Author(s):  
Filippo Passetti ◽  
Claire Dibben
Keyword(s):  
Physical Illness ◽  
Working Time ◽  
European Working ◽  
The Impact
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