Optimal Operation Planning for Integrated Forest Harvesting and Transport Operations from the Forest to the Mill

Forest harvesting systems vary from place to place. This paper concentrates on the study of one of the most complex systems, multistage timber production, which is very popular in vast forest regions of China and Russia. Based on case studies from the Heilongjiang Forest Region, in the northeast part of China, optimal operation planning for forest harvesting, and the impact of harvesting on the forest environment, economic benefit and working safety, is carried using a multi-objective optimization model. The results of the case studies, optimizing operation time schedules, show that the models are quite applicable and helpful to practical operations

Assessment of Animal Skidding and Ground Machine Skidding Under Mountain Conditions

The proportion of animal skidding in forest operations in Heilongjiang Forest Region has increased significantly in recent years. First, the development of animal skidding and machine skidding was demonstrated and analyzed. Then, two methods of ground skidding currently used in this region were evaluated both individually and comprehensively using the following criteria: operation efficiency or operation cost, degree of damage on soil and on residual stands, accident rate, and natural regeneration. Finally, according to the results of synthetic assessments, classification of operational conditions suitable to each skidding method were recommended quantitatively with considerations of multiple evaluation criteria

Development of Forest Engineering in China — Looking Ahead Ten Years

This paper highlights the development and prediction of forest engineering and forest engineering education in China. The activities of forest engineering has changed significantly since the introduction of a market economy into China. Profitability and economic efficiency are emphasized. Techniques and education systems in forest engineering must not be transferred mechanically from other countries. They must match existing social, economic, and physical conditions. The importance of forests in supplying non-wood forest products such as water and soil protection, climate adjustment, honey, nuts, mushrooms, medical plants and wildlife need to be considered when decisions are made about forest engineering activities, such as forest harvesting. Forest operations, as an important part of integrated forestry, should be planned from the point of view of sustainability of both timber and non-timber forest products. It is evident that a concerted effort is needed to encourage forest development programs that harmonize interests in conserving forests as well as to wisely use the potential of the forest while maintaining its full regeneration capacity. All forest engineering activities, such as forest resource surveying and harvesting planning, forest road planning and construction, harvesting , post-harvesting site disposal, planting and protection and so on should serve the key purpose of sustainable forestry. In view of the forest quality decline in China, it is essential that forest engineering practices are carried out in a manner to guarantee the sustainability of the forest resources base. "The Natural Forest Protection Project”, just started in 1998 in China brings challenges and changes to forest engineering. The environmentally sound, low cost and high efficient techniques of forest engineering will be the spotlight of research in the future

Modeling and Validating the Grabbing Forces of Hydraulic Log Grapples Used in Forest Operations

The grabbing forces of log grapples were modeled and analyzed mathematically under operating conditions when grabbing logs from compact log piles and from bunch-like log piles. The grabbing forces are closely related to the structural parameters of the grapple, the weight of the grapple, and the weight of the log grabbed. An operational model grapple was designed and tested to validate grabbing forces of the mathematical models while grabbing logs from five alternative diameter classes under two different working conditions. The working conditions and log sizes affected the grabbing forces significantly. Validation results suggest that the mathematical models developed can be used to estimate the grabbing forces required in the design process of log grapples. The results can be used by equipment manufacturers and researchers involved in the engineering design of grapples used in harvesting operations

Correlated electronic states at domain walls of a Mott-charge-density-wave insulator 1T-TaS2

Domain walls in interacting electronic systems can have distinct localized states, which often govern physical properties and may lead to unprecedented functionalities and novel devices. However, electronic states within domain walls themselves have not been clearly identified and understood for strongly correlated electron systems. Here, we resolve the electronic states localized on domain walls in a Mott-charge-density-wave(CDW) insulator 1T-TaS2 using scanning tunneling spectroscopy. We establish that the domain wall state decomposes into two nonconducting states located at the center of domain walls and edges of domains. Theoretical calculations reveal their atomistic origin as the local reconstruction of domain walls under the strong influence of electron correlation. Our results introduce a concept for the domain wall electronic property, the wall's own internal degrees of freedom, which is potentially related to the controllability of domain wall electronic properties

The direct observation of ferromagnetic domain of single crystal CrSiTe3

Layered van der Waals interacting system that can be exfoliated to few layers are promising for exploring fundamental physics with rich electronic and optical properties. Combining the emerging phenomenon with long-range magnetic orders could lead to novel potential ultra-compact spintronics. Recently, CrXTe3 (X= Ge, Si) were reported that can persist magnetism after being exfoliated to few layers, however the magnetic domain structure in layered or bulk single crystal has remained unexplored. Here we choose CrSiTe3 single crystal as a model system, combining low-temperature magnetic force microscope, to demonstrate the magnetic domain structure, as well as the domain evolution in the presence of magnetic field, which is consistent with the magnetic behaviors measured by Magnetic Properties Measurement System (MPMS). Our result gives a simple portray of the magnetic properties of single crystal CrSiTe3, which provides a basis for the future research on magnetic layered van der Waals interacting system in potential application at 2-dimensional limit

Heat transport study of the spin liquid candidate 1T-TaS2

We present the ultra-low-temperature thermal conductivity measurements on single crystals of the prototypical charge-density-wave material 1$T$-TaS$_2$, which was recently argued to be a candidate for quantum spin liquid. Our experiments show that the residual linear term of thermal conductivity at zero field is essentially zero, within the experimental accuracy. Furthermore, the thermal conductivity is found to be insensitive to the magnetic field up to 9 T. These results clearly demonstrate the absence of itinerant magnetic excitations with fermionic statistics in bulk 1$T$-TaS$_2$ and, thus, put a strong constraint on the theories of the ground state of this material.Comment: 5 pages, 3 figure

The low-temperature highly correlated quantum phase in the charge-density-wave 1T-TaS_2 compound

A prototypical quasi-2D metallic compound, 1T-TaS_2 has been extensively studied due to an intricate interplay between a Mott-insulating ground state and a charge density-wave (CDW) order. In the low-temperature phase, 12 out of 13 Ta_{4+} 5\textit{d}-electrons form molecular orbitals in hexagonal star-of-David patterns, leaving one 5\textit{d}-electron with \textit{S} = 1/2 spin free. This orphan quantum spin with a large spin-orbit interaction is expected to form a highly correlated phase of its own. And it is most likely that they will form some kind of a short-range order out of a strongly spin-orbit coupled Hilbert space. In order to investigate the low-temperature magnetic properties, we performed a series of measurements including neutron scattering and muon experiments. The obtained data clearly indicate the presence of the short-ranged phase and put the upper bound on ~ 0.4 \textit{\mu}_B for the size of the magnetic moment, consistent with the orphan-spin scenario.Comment: 11 pages, 4 figures + supplemental material. Accepted by npj Quantum Material