ALBERT

Description: A total of 344 soil cores were taken in annually cropped fields of Alberta, Saskatchewan, Manitoba, and Ontario from 2011 to 2013 in areas where the field shapes, or obstacles within fields, required the driving pattern of farm operations to overlap. Soil nitrate-N concentrations in overlapping areas were 60% greater, soil Olsen-P concentrations were 23% greater, and pH was 0.5 units greater at 0–15 cm depth compared with non-overlapping areas, suggesting smaller nutrient use efficiency and potential for greater nutrient loss.

Description: Differences in soil water retention (SWR) characteristics between soil types and the factors driving those differences provide important information for land management, particularly in regions such as the Colombian Andes, which have limited water-storage infrastructure and where soils provide plant-available water and other ecosystem services. The objective of this study was to explore relationships between SWR and physical, chemical, and mineralogical properties of Andisols and Inceptisols through a case study of two watersheds in the Colombian Andes. This study identified a complex relationship between total carbon (TC), short-range order (SRO) minerals, and SWR. Both soil types had high SWR, with volumetric water content at permanent wilting point between 39% and 53%. Principal component analysis showed association of SWR with TC, SRO minerals, and % clay in both soil types. The Andisols of this study were coarse textured, allophanic (rich in allophane and imogolite — up to 17% in the B horizon), and with up to 15% TC in the A horizon. In contrast, the Inceptisols were fine textured (〉30% clay) and higher in ferrihydrite than the Andisols. The formation of organo-metallic complexes was observed in A horizons; however, TC was lower under pasture than forest in both soil types. The addition of organic matter to soils with SRO minerals, such as the soils of this study, may foster the formation of organo-metallic complexes, stabilize soil C, and enhance SWR. Consequently, both study sites may benefit from management practices that increase soil organic matter.

Description: This study investigated differences in forest structure, organic layer thickness, soil organic carbon, and permafrost depth between late successional (LS) and post fire (PF, 90 to 120 years since burn) plots under black spruce (Picea mariana (Mill.) BSP) on fine-textured, poorly drained lacustrine sediments in the Copper River Basin, Alaska. We found that although live stem and seedling density and organic layer thickness (OLT) was not significantly different between PF and LS plots (28 ± 7 cm and 31 ± 10 cm, respectively), soil organic carbon (SOC) stocks (30 ± 10 kg m-2 and 46 ± 12 kg m-2, respectively), and permafrost depth (90 ± 28 cm and 56 ± 12 cm, respectively) remain significantly different. OLT was linearly related to 1 m SOC stocks for LS plots but not for PF plots, and LS plots had a greater proportion of highly decomposed (humic) material in the organic layer. Soil properties on PF plots appear to be on a trajectory of recovery towards LS plots with respect to SOC stocks, permafrost depth, and organic layer composition, but remain different despite nearly 100 years since fire disturbance and therefore potentially sensitive to changes in future fire frequency or climate.

Description: Global change-driven droughts are triggering worldwide forest dieback which are predicted to increase even further. Here, we combined genome-wide single nucleotide polymorphisms (SNPs) and dendrochronological approaches to assess genetically-based individual tree vulnerability to past extreme droughts that caused massive mortality of Nothofagus dombeyi forests in northern Patagonia. We collected fresh leaves and wood cores from pairs of Healthy Crown (HC) and Partially Affected crown (PA) trees at four sites impacted by 1998, 2008 and 2014 droughts. We used dendrochronological techniques to estimate parameters in terms of growth trends due to drought and genomic analysis to assess its relationship with water stress. While 5,155 neutral loci did not discriminate PA from HC trees, a set of 33 adaptive SNPs did so, 8 of which were related to hydric stress. Association analysis between genomic variants and dendrophenotypic traits yielded 6 SNPs that were associated with a growth measure as resilience to cope with drought. Our preliminary results indicate that susceptibility to drought in N. dombeyi could be determined at the genomic level. The combination of both approaches provides a framework for the identification and analysis of candidate genes for stress response in non-model species.

Description: Various space missions, including the Russian and Chinese interplanetary exploration collaboration in 2011 and the Phobos-Grunt space project to be relaunched by the Chinese in 2025, carry a soil preparation system (SOPSYS), which is an instrument used for scientific experiments. The design and manufacture of this precision instrument require stringent manufacturing processes and workflow of the highest quality, with every process in the project carefully monitored and controlled. All processes should be completed within the deadline so that the space project can be launched at the scheduled time. The colored Petri net (CPN) modeling method can describe a variety of resource types and execution logic, and it can be formally verified. Based on these advantages, we clearly describe the complex structure of the SPOSYS unit production process. In addition, we use critical time and the 6 sigma system to evaluate the availability and reliability of workflows, and we use elimination and simplification (ECRS) methods and constraint theory to improve the manufacturing process of the SOPSYS unit. We further provide optimization theories, methods, and insights for workflow management in time-sensitive and independent manufacturing systems.

Description: With the increasingly close relations between cities in China, it is of great significance to explore the regular characteristics of the intercity connection. Through Tencent’s population migration heat and Baidu map big data, this paper analyzes the regular characteristics of the relations between complex cities based on such index as the rich node propensity index, preference level index, and relative heat index and also investigates the influence of geographical proximity factors on the external relations of different cities. The research has the following results. Firstly, the relations between cities have obvious club characteristics. The rich nodes tend to connect with the rich nodes, while the nonrich nodes tend to connect with the nonrich nodes. Secondly, the connection between cities has the effect of hierarchical proximity, and cities mainly establish spatial connections with cities of the same level and adjacent level. Thirdly, the relations between cities also have the effect of geographical proximity, and the degree of influence of geographical proximity in low-level cities is greater than that in high-level cities. Fourthly, the external connection mode of high-level cities is to establish close contact with high-level cities adjacent to the level, with strong attraction to low-level cities adjacent to the location at the same time. The low-level cities are closely related to the high-level cities adjacent to the location and other cities of geographical proximity or adjacent level. This study helps to further understand the complex characteristics and laws of intercity connections and urban networks.

Description: In Nepal, forest management priority is shifting to scientific management from conventional management. Though, the forest officials claims that scientific management is beneficial to the forest user groups, comparative financial assessment with conventional management remains unexplored. Following a case study approach, this study compares financial efficiency of two forest management systems in the community forests, focusing on benefit-cost ratio. The study conducted documents review, focus group discussions, and rapid survey to quantify costs and benefits from each forest management system. Conventional management gave a higher benefit-cost ratio to the forest user groups, irrespective of whether forest products are sold at a subsidized price or par with the market price. However, scientific management required high forest management costs and thus had a lower benefit-cost ratio. Sensitivity analysis between two systems revealed that conventional management gave a higher benefit-cost ratio in all cases. The study concludes that forest user groups would bear financial loss if they do not fix the price of the timber at par with the market in scientific management, and in such a case, the tagged price will be beyond affordability of the forest users. Furthermore, scientific management has discouraged kind contribution of users in managing forest. Besides, social and environmental consequences of scientific management cannot be ignored. Hence, the study argues for reconsidering current scientific management considering likely economic and social consequences to the forest user groups.

Description: A tuned mass damper inerter (TMDI) is a new class of passive control device based on the inclusion of an inerter mechanism into a conventional tuned mass damper (TMD). The inerter device provides inertial resisting forces to the controlled system, through relatively small masses, converting it in a mechanism with the potential to enhance the performance of passive energy dissipating systems. This work presents a study of an optimal TMDI design through an exhaustive search process. TMDI device design using the cited parameter selection methodology consists in the determination of the damper critical damping ratio, ζTMDI, and frequency ratio, υTMDI, which result in the minimum structural response of a multidegree of freedom structural system, considering predefined values for mass ratio (µ) and inertance ratio (β). The used optimization process examines all possible damping device design parameter combinations to select the set of values that results in the best device performance to reduce response parameters in a structure. Four different optimization processes are performed by independently minimizing four performance indices: J1 associated to the reduction of the structure’s maximum peak displacement, J2 calculates the minimal RMS value for the structure’s peak displacement, J3 seeks by the minimal peak interstorey drift, and JP determines the lowest value for a linear weighted combination of the abovementioned three indices. A numerical example is developed with the purpose of validating the proposed optimization procedure and to evaluate the benefits of using TMDI as controlling devices for structures under seismic excitation, by carrying out a comparative analysis to contrast the performance of the optimization alternatives developed, running up to 1968192 cases. The obtained results show that devices designed based on exhaustive search optimization produce peak displacement reductions of up to 35% and peak structure displacement RMS reductions of up to 30%.

Description: Controlling and maintaining the orientation of the balloon-borne gondola for high-altitude flight is a prerequisite for ensuring the pointing control of observation instruments. When the balloon-borne gondola is flying in the stratosphere of the atmosphere, the existing external interferences will be converted into the coupling moment to the azimuth control system. Meanwhile, those uncertain factors and the frictional nonlinearity of the control system will also cause a certain magnitude of coupling moment. The existence of such coupling moment largely impacts on the accuracy and stability of the orientation control for the angular momentum exchange devices of the balloon-borne gondola. To address such an issue, this paper proposes and implements a novel type of integrated decoupler device. With this decoupler adopted, the aziDmuth control system could sense the existence of coupling torque and azimuth fluctuations quickly and suppress the influences of external interference, uncertain factors, and system structure nonlinearity on the azimuth control effectively, thereby improving the control accuracy of the azimuth control system. Both simulations and experiments are conducted to verify the effectiveness of the proposed device. The results show that the integration of the decoupler and the controller of the azimuth control system provide the azimuth control of the balloon-borne gondola with high accuracy and stability. Such a decoupler device design has a broad potential and could not only be used for balloon-borne gondola control but also could be applied onto other control systems using angular momentum exchange devices as actuators.

Description: Gates are important operating facilities and resources in civil airports. It is a core task in the airport operation management to select reasonable gates for inbound and outbound flights. We present a continuous time formulation with second-order cone programming (SOCP) for the gate assignment problem which allocates flights to available gates to optimize both the transfer time of passengers and the robustness of the airport operations schedules. The problem is formulated as a mixed integer nonlinear program, and then, the quadratic objective that minimizes the walking distance of transferring passengers is linearized, and the objective that minimizes the variance of idle time at the gates is transformed to a second-order cone constraint with a linear objective function. Then, a Lagrangian relaxation algorithm is developed by exploiting the problem structure. Computational tests are carried out to illustrate the efficiency of the model and the algorithms. It is shown that the continuous time formulation is more efficient than the existing model, and the Lagrangian relaxation algorithm can obtain better solutions faster than a commercial solver.