The optimal rotation of a flammable forest stand when both carbon sequestration and timber are valued: a multi-criteria approach

This paper proposes a multi-criteria approach that accounts for the risk of fire when determining the optimal rotation of a forest stand that is being managed for both timber production and carbon sequestration purposes. The multi-criteria framework uses in a combined way, multi-objective optimization and compromise programming methods. The proposed approach is computationally simple and allows for the quantification of conflicts between the criteria considered through the elicitation of the corresponding Pareto frontiers. Once the best portion or compromise sets of the Pareto frontiers are determined, then some indications of the increase in social welfare due to a potential reduction in the risk of fire are obtained. We illustrate the use of our methodology by applying it to an example that has previously been investigated in the forestry literature. Finally, some potential policy implications derived from the results obtained are highlighted.     

Accidental torsion in buildings due to stiffness uncertainty

Discrepancies between the computed and actual values of the structural element stiffness imply that a building with nominally symmetric plan is actually asymmetric to some unknown degree and will undergo torsional vibration when subjected to purely translational ground motion. Such accidental torsion leads to increase in structural element deformations which is shown to be essentially insensitive to the uncoupled lateral vibration period of the system but is affected strongly by the ratio of uncoupled lateral and torsional vibration periods. The structural deformations increase, in the mean, by at most 10 and 5 per cent for R/C and steel buildings, respectively, and by much smaller amounts for a wide range of system parameters. The increase in structural deformations due to stiffness uncertainty is shown to be much smaller than implied by the accidental torsional provisions in the Uniform Building Code and most other building codes.     

Passing volume calculation system (PVCS): computer software for managing data on watersheds that produce mud flows and the case of Quebrada La Cadena,Antofagasta, Chile

Severe storms in desert regions, especially along the coastal area of the Chilean desert, produce very destructive mud flows that last a few hours and constitute the only surface run-off in these events. To date, there is no simple or practical methodology for assessing such mud flows. Given the settlement of mining fields and creation of desert campgrounds, it is increasingly necessary to understand how these water and/or mud flows behave in order to develop structural and non-structural mitigation plans. Thus, herein, we present software known as PVCS, which provides a system for calculating mud volumes after a strong storm. This hydrological and computer tool allows us to calculate the structure and volume of mud passing through the mouth of a hydrographic watershed after a desert rainstorm. To use this software, it is necessary to know the hydrological, meteorological, and morphometric parameters of the watershed under study. These data are entered into a model that estimates the amount of mud that will pass through the mouth with each hour of rain. Simulations can be done with historical data or data designed for future events, thereby allowing the preparation of measures to protect people and property. We use the watershed Quebrada La Cadena to exemplify the use of this software. This drainage basin is located on the western slope of the Chilean Coastal Range in Antofagasta, a city in northern Chile. Here, rain in June 1991 produced a destructive flood that killed nearly one hundred people living at the main mouth of the watershed and caused huge economic losses. Data from this catastrophe have significantly improved the understanding of such flows, and this has been incorporated into the software. The principal value of PVCS lies in its ability to forecast the volume of mud that will result from a storm and hourly outflows that will pass through a specific populated area, mining camp, or industrial plant located in the mouth of a watershed of any size. This information is used to determine the most critical moment, i.e., the time of the largest outflows, which can then be used to organize timely evacuations to safe places for people, animals, and machines. Moreover, the program is methodologically valuable since, in order to implement PVCS, the user must structure information in a hydrological way. In summary, this program simulates different rain scenarios, thereby allowing us to design structural mitigation projects and contingency plans.     

Magnetostratigraphy and environmental magnetism in a Pleistocene sedimentary sequence, Marcos Paz, Argentina

The deterioration of groundwater quality, particularly due to salinization, because of the overexploitation of groundwater in the Lower Central Plain of Thailand remains a major concern. With increasing demand for water there is a growing need for sustainable management of the resource, which would benefit from an improved understanding of the sources of chloride contamination. Thus, a hydrochemical and isotopic study was carried out to chemically characterize groundwater and to investigate possible sources of salinization, and in particular of chloride contamination, in the multi-layered Bangkok aquifer system. Groundwater samples were taken from four topmost aquifers (Bangkok, Phra Pradaeng, Nakhon Luang, and Nonthaburi). Additionally, short-term rainwater sampling, as well as river and seawater sampling was performed and later analyzed for ionic composition and stable water isotopes. Ionic and isotopic data indicate at least three different recharge sources for groundwater. The major recharge source is rainwater. The influence of seawater is limited to the coastal region and tidally influenced areas of the two main rivers (Chao Phraya and Tha Chin). Bromide data also suggest the influence of saline water in deeper aquifers due to trapped water. Most importantly, although the influence of seawater on groundwater is recognizable, the surrounding geology contributes a significant number of dissolved ions detected in the groundwater.     

Anodic Oxidation as Green Alternative for Removing Diethyl Phthalate from Wastewater Using Pb/PbO2 and Ti/SnO2 Anodes

The electrochemical oxidation (EO) of diethyl phthalate (DEP) in aqueous solution was studied at Pb/PbO₂ and Ti/SnO₂ anode materials under galvanostatic‐experimental conditions. Results obtained clearly demonstrated that the anode plays a significant role for the optimization of the oxidation process, deciding the mechanisms and by‐products formed. DEP and by‐products of oxidation were also analyzed during various stages of the electrolysis reaction by HPLC and GC/MS techniques. Before the analysis by GC/MS technique, the samples were treated by solid phase microextraction (SPME) in order to concentrate the compounds from the reaction solution and identify all electrolysis intermediates. Current efficiencies (instantaneous current efficiency; ICE and total current efficiency; TCE) achieved during EO experiments were dependent on anode used and current density (20–40 mA cm^?2) at 40°C. The results obtained demonstrated that the environmental electrochemical methods can be a feasible alternative for the wastewater treatment containing hazardous phthalates.