Wyniki wyszukiwania - BazTech

1

Application of supply chain management in construction industry

Nguyen Phong Thanh, Nguyen Vi Nguyen, Pham Luan Hong, Nguyen Thu Anh, Nguyen Quyen Le Hoang Thuy To, Huynh Vy Dang Bich

Advances in Science and Technology. Research Journal

|

2018

|

Vol. 12, no 2

11--19

EN

The application of the supply chain management (SCM) in industry has achieved much success, especially in the manufacturing sector. In the current market, the Vietnamese construction companies must compete not only with domestic companies but also with foreign ones, the application of SCM is essential to improve efficiency and increase their competitive advantage. In this paper, a survey was carried out to identify factors that cause limitation in applying SCM to the Vietnamese construction industry. A qualitative approach was based on prime contractor’s perspective at the construction phase of the project. The survey questionnaire was designed by synthesizing and inheriting the previous studies and consultation with experts. The survey participants are those who have had working experience with main contractors and joined in the construction projects. The face-to-face interviews were conducted to collect data. Descriptive statistics analysis and Exploratory Factor Analysis (EFA) were used to analyze data. The results indicated seven leading causes which limited the application of SCM in the construction industry.

2

Climatic Response of Tracheid Features of Picea meyeri Along Altitude Gradient of Luyashan Mountains of North China

Wang M., Jiang Y., Zhang W., Dong M., Kang M., Xu H.

Polish Journal of Ecology

|

2017

|

Vol. 65, nr 4

345--358

EN

Changing localized environmental conditions along altitude gradients could modify the responses of tree xylem structures to climate variations. To explore how trees adapt to local environment and respond to climate variants, we analysed the variation of Picea meyeri xylem tracheid features and the relationships with climate variables along an altitude gradient (1970, 2240, 2490 and 2650 m above sea level) of the Luyashan Mountains in the North China. The results mainly indicated the following: (1) tracheid number and diameter of P. meyeri showed significant differences among the four sites along the altitude gradient; (2) trees at site 2 (2240 m) and site 3 (2490 m) are similar in age, but the xylem tracheid number and diameter of these trees were significantly different, which may indicate different functional adaptation; (3) the relationships between xylem features' residual chronologies and the monthly climate data were inconsistent along altitude gradients, which indicated that the limiting factor of P. meyeri growth along the altitude gradients, shifted from drought stress at lower altitudes to low-temperature stress at higher altitudes.

3

Decision-making of spare subsea trees with multi-restrictive factors in deepwater development

Chen J., Duan M., Zhang Y.

Eksploatacja i Niezawodność

|

2016

|

Vol. 18, no. 4

590--598

EN

In order to quantify the influential factors of subsea trees’ maintenance proactively, multiple restrictive factors first are elaborated, such as locale meteorological conditions (i.e. weather), transport resources, heavy intervention vessels, maintenance technicians, spare trees and so on. Then, the focus is on three vital factors: weather, intervention vessel and spare trees. These restrictions dramatically impact the cost and accessibility of maintenance. For the inaccessible duration of significant wave height in weather model for computing non-feasibility days, we utilized the statistic data from the ERA Interim dataset. An analytical model is established to simplify the calculation of maintenance costs. As the predictive maintenances are seldom performed in subsea field, the built maintenance model only considers the corrective maintenance. Results show that hostile weather as well as the shortage of adequate spare subsea trees can induce severe downtime cost. The comparison of two contractual alternatives indicates that the better way to reduce the maintenance cost is to make the intervention vessel available enough. It is significant to provide quantitative views of subsea maintenance and to supply a method for the decision-making of spare subsea trees with multiple restrictive factors from the proposed model.

PL

Aby móc dokonać aktywnej oceny ilościowej liczących się czynników utrzymania podmorskich głowic eksploatacyjnych, najpierw zbadano wiele czynników ograniczających, takich jak lokalne warunki pogodowe oraz dostępność środków transportu, statków interwencyjnych o dużym tonażu, techników utrzymania ruchu, zapasowych głowic eksploatacyjnych, itd. Następnie skupiono uwagę na trzech kluczowych czynnikach: pogodzie oraz dostępności statku interwencyjnego oraz dostępności zapasowych głowic eksploatacyjnych. Ograniczenia związane z tymi czynnikami znacząco wpływają na koszty i możliwości konserwacji. Do obliczenia okresów,w których wysokie fale uniemożliwiają prace konserwacyjne wykorzystano dane statystyczne pochodzące z bazy danych ERA Interim. Stworzono model analityczny pozwalający na uproszczenie obliczeń kosztów utrzymania ruchu. Ponieważ na podmorskich polach naftowych rzadko wykonuje się zabiegi predykcyjnego utrzymania ruchu, skonstruowany przez nas model utrzymania ruchu uwzględnia jedynie utrzymanie naprawcze. Wyniki pokazują, że niekorzystne warunki pogodowe, jak również brak odpowiednich zapasowych głowic eksploatacyjnych mogą generować wysokie koszty związane z przestojami. Porównanie dwóch alternatyw pokazuje, że najlepszym sposobem na zmniejszenie kosztów utrzymania ruchu jest zapewnienie dostatecznej dostępności statku interwencyjnego. Proponowany model umożliwia ilościowy ogląd utrzymania ruchu w warunkach podmorskich i może być wykorzystany w procesie podejmowania decyzji dotyczących wykorzystania zapasowych podmorskich głowic eksploatacyjnych uwzględniającym wiele czynników ograniczających.

4

Recruitment pattern of tree populations along an altitudinal gradient : Larix chinensis Beissn in Qinling Mountains (China)

Duan R., Wang X., Tu Y., Huang M., Wang C., Zhu Z., Guo H.

Polish Journal of Ecology

|

2009

|

Vol. 57, nr 3

451-459

EN

Larix chinensis Beissn is an endangered plant found only in the Qinling Mountains, Shaanxi, northwestern China. It is densely distributed in the alpine and subalpine belt on their highest peak Taibai Mountain. Age structure studies along a montane altitudinal gradient would be helpful in understanding the limiting factors on the regeneration of natural forests. The forest was divided into three transects, i.e., lower limit (2900-3000 m), mid-altitude (3100-3200 m) and upper limit (3300-3400 m). The age structures differed across altitude classes. The age structure in the low altitude transect was closed to bell-shaped and characterized by the dominance of adult trees. A reverse-J shape age structure was found in the mid-altitude transect. Multi-modal age distribution was found in the high altitude transect, and was caused by lack of young seedlings and saplings. This suggests that different limiting factors play important roles in shaping the age structure and forest regeneration at different altitudes. In the low altitude, light availability was probably the most important limiting factor. In the mid-altitudinal transect, density dependent intraspecific competition between trees likely controlled regeneration of L. chinensis. We suggest that limiting climatic factors, e.g. temperature, play an important role in determining the age structure of L. chinensis populations in highaltitude areas.