Estimation of the atmospheric boundary layer height during different atmospheric conditions: a comparison on reliability of several methods applied to lidar measurements

The performance of six numerical methods usually used to determine the atmospheric boundary layer (ABL) height from lidar measurements was investigated under different atmospheric conditions: results were compared with those obtained from radiosoundings to analyse their reliability for ABL-height retrievals. The selected methods were the gradient method (GM), the logarithm gradient method (LGM), the inflection point method (IPM), the wavelet covariance transform (WCT), the centroid/variance method (VM), and the cluster analysis (CA). Lidar measurements were carried out in the frame of the ‘Atmospheric Minor Species relevant to the Ozone Chemistry’ (AMISOC) project during a multi-instrument campaign conducted at the INTA/Atmospheric Observatory ‘El Arenosillo’ (INTA/ARN) in south-western Spain from 15 May to 20 June 2012. The goal of this work is to analyse the performance and robustness of the different lidar methods in this region, characterized by particular atmospheric conditions. In particular, both events of sea–land breeze regimes and episodes of Saharan dust intrusions were studied. In most days, similar results were obtained by all lidar methods in the events of sea–land breeze regimes, presenting relative absolute differences between lidar and radiosounding retrievals below 12% in average. However, big discrepancies between lidar and radiosounding retrievals are found when residual layers are present in the measurements. In such cases, the vertical extension of lidar and radiosounding profiles must to be limited to the altitude of the residual layer bottom. In a second analysis, focused on diurnal variability in the ABL heights under non-dusty (ND) and dusty (DD) conditions, the methods were tested against intensive radiosoundings launched every 4 h over 2 days. Under ND conditions, the best results were achieved for the LGM, presenting a mean of the relative absolute differences respect to radiosounding measurements of 10%. The rest of methods also provided good results with relative differences below 20% in average. Under DD conditions, however, an increase of the relative differences is found with mean values of up 32%. In this case, best results are given by CA with a mean relative difference of 20%. Despite the limited data set used in this work, results show that unlike the ND conditions for which all lidar methods provide good results respect to radiosounding retrievals, under DD conditions the election of the lidar method is a key factor for ABL estimation. However, we remark the need of extending our analysis to longer periods of time to better characterize the differences observed in this work.     

Increasing the Level of Automation in the Forestry Logging Process with Crane Trajectory Planning and Control

Working with forestry machines requires a great deal of training to be sufficiently skilled to operate forestry cranes. In view of this, it would be desirable within the forestry industry to introduce automated motions, such as those seen in robotic arms, to shorten the training time and make the work of the operator easier. Motivated by this fact, we have developed two experimental platforms for testing control systems and motion‐planning algorithms in real time. They correspond to a laboratory setup and a commercial version of a hydraulic manipulator used in forwarder machines. The aim of this article is to present the results of this development by providing an overview of our trajectory‐planning algorithm and motion‐control method, with a subsequent view of the experimental results. For motion control, we design feedback controllers that are able to track reference trajectories based on sensor measurements. Likewise, we provide arguments to design controllers in an open‐loop for machines that lack sensing devices. Relying on the tracking efficiency of these controllers, we design time‐efficient reference trajectories of motions that correspond to logging tasks. To demonstrate performance, we provide an overview of extensive testing done on these machines.     

The behaviour of consolidated Neapolitan yellow Tuff against salt weathering

Bulletin of Engineering Geology and the Environment - Salt crystallization is a strong weathering agent in porous building materials. The crystallization pressure exerted by salt crystals, growing...     

Spice use in food: Properties and benefits

Spices are parts of plants that due to their properties are used as colorants, preservatives, or medicine. The uses of spices have been known since long time, and the interest in the potential of spices is remarkable due to the chemical compounds contained in spices, such as phenylpropanoids, terpenes, flavonoids, and anthocyanins. Spices, such as cumin (cuminaldehyde), clove (eugenol), and cinnamon (cinnamaldehyde) among others, are known and studied for their antimicrobial and antioxidant properties due to their main chemical compounds. These spices have the potential to be used as preservatives in many foods namely in processed meat to replace chemical preservatives. Main chemical compounds in spices also confer other properties providing a variety of applications to spices, such as insecticidal, medicines, colorants, and natural flavoring. Spices provide beneficial effects, such as antioxidant activity levels that are comparable to regular chemical antioxidants used so they can be used as a natural alternative to synthetic preservatives. In this review, the main characteristics of spices will be described as well as their chemical properties, different applications of these spices, and the advantages and disadvantages of their use.     

Characterization of micellar systems produced by new amphiphilic conjugates of poly(ethylene glycol)

This study proposes polymeric micelles produced using new amphiphilic conjugates between amino- or carboxy-mPEG₂₀₀₀ and three different α-lipoamino acids (PEG-LAA). The characterization of these colloidal systems showed CMC values, in the order of 10^?5?M, that are interesting in the view of an in vivo administration. The PEG-LAA micelles also showed a good stability at 37?°C and upon dilution in aqueous media. Using a colored probe as a model lipophilic compound, the loading efficiency and in vitro release profile were also outlined.     

FAME Production and Fatty Acid Profiles from Moist Chlorella sp. and Nannochloropsis oculata Biomass

In the present study, we investigated the production of fatty acid methyl esters (FAME) from moist Chlorella sp. and Nannochloropsis oculata biomass using a hydrolysis–esterification process. Additionally, we evaluated for the first time the fatty acid profile before and after this process. Hydrolysis of the lipid fraction was performed on a moist biomass in the presence of differing amounts of an acid catalyst in both 50 and 100 % w/w water relative to the biomass. The esterification of the crude extracts of the free fatty acids (FFA) was then investigated. The experiments show that in the presence of 50 % w/w water relative to the biomass, the hydrolysis–esterification process results in higher FFA and FAME yields. The analysis of the fatty ester profiles did not reveal any degradation of the FFA from the microalgae biomass under the hydrolysis–esterification conditions. The results were compared with both extraction–transesterification and direct transesterification processes using dry biomass. The extraction–transesterification and hydrolysis–esterification processes resulted in similar FAME yields and similar profiles of the fatty esters from dry and moist biomass materials, respectively.     

变幅油缸摩擦力的研究及其在力矩限制器中的应用

通过对汽车起重机臂架系统及其变幅油缸的受力分析,结合大量试验数据与理论函数推导出变幅油缸摩擦力的函数关系,并成功地应用于力矩限制器的研发中。基于该摩擦力函数模型开发的力矩限制器,载荷精确计算的误差控制在±4％内,国标为±5％,并已经批量生产及应用。     

Color‐Coded Super‐Resolution Small‐Molecule Imaging

Although the development of super‐resolution microscopy dates back to 1994, its applications have been primarily focused on visualizing cellular structures and targets, including proteins, DNA and sugars. We now report on a system that allows both monitoring of the localization of exogenous small molecules in live cells at low resolution and subsequent super‐resolution imaging by using stochastic optical reconstruction microscopy (STORM) on fixed cells. This represents a powerful new tool to understand the dynamics of subcellular trafficking associated with the mode and mechanism of action of exogenous small molecules.