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This paper presents, in a descriptive and didactic way, the construction of a robotic platform, detailing the necessary components for this and the assembly process. This is done in order that students with limited engineering fundamentals, can build the model of a robotic platform without much difficulty and that this also helps them to implement control, navigation and monitoring algorithms that they will later know in the development of their studies.

In this paper, a practical comparison is performed between the use of the principal component analysis method (PCA) and the multidimensional scaling method (MDS) for image classification applications, where the images under study are contaminated using different tools. Here, characteristics of these images are obtained and, according to criteria for measuring the distance between the images, their classification is carried out. For the case under study, it can be said that the classification using PCA performed better than the classification using MDS.

In this chapter, the almost periodicity of the first principal components is used to carry out the reconstruction of images. First, the principal component analysis technique is applied to an image. Then, the periodicity of its principal components is analyzed. Next, this periodicity is used to build periodic vectors of the same length of the original principal components, and finally, these periodic vectors are used to reconstruct the original image. The proposed method was compared against the JPEG (Joint Photographic Experts Group) compression technique. The mean square error and peak signal-to-noise ratio were used to perform the above-mentioned comparison. The experimental results showed that the proposed method performed better than JPEG, when the original image was reconstructed using the principal components modified by periodicity.

In this paper, a method for image classification based on multidimensional scaling (MDS) is presented. Once the image has been fragmented into smaller cells and the wavelet decomposition has also been performed, up to a certain level, statistics are obtained from the new cells with the aim of constructing vectors of characteristics of the original image. Then, these vectors are grouped in a matrix and the MDS of said matrix is performed. Finally, the principal coordinates of the MDS indicate the proximity between vectors and, therefore, between images.

In this chapter, an introduction to the basics of principal component analysis (PCA) is given, aimed at presenting PCA applications to image compression. Here, concepts of linear algebra used in PCA are introduced, and PCA theoretical foundations are explained in connection with those concepts. Next, an image is compressed by using different principal components, and concepts such as image dimension reduction and image reconstruction quality are explained. Also, using the almost periodicity of the first principal component, a quality comparative analysis of a compressed image using two and eight principal components is carried out. Finally, a novel construction of principal components by periodicity of principal components has been included, in order to reduce the computational cost for their calculation, although decreasing the accuracy.

The frequency-domain analysis of the performance of a wind turbine that is placed in a mountainous complex terrain is presented. The variables of interest were the wind speed and the active power of the wind turbine, and the experimental data for the analysis were collected for three months with a sampling time of 10 minutes. The power spectral density (PSD) of the wind speed and of the active power of the wind turbine were obtained for every day of the three months under analysis, and this information was used to estimate the magnitude squared of the frequency response of the system and to estimate the average value of the magnitude squared of the frequency response. Then, the energy distribution of the wind turbine over a range of frequencies was analysed.

Excess fluid leak-off, a challenge in Kuwait's naturally fractured tight carbonate formations, can compromise post-fracture productivity. Past acid fracture treatments, both for moderate and high temperature formations failed to generate the long differently etched fracture due to excessive leak-off. Treating zones with multiple perforated intervals in a single stage, particularly in pay zones with long heterogeneous rock properties can result in non optimal stimulation. Therefore, a new approach was developed with proven success to enhance fracture conductivity and overall production by efficient control of fluid leak-off. This novel approach incorporates the use of far-field and near-wellbore diverting systems into the acid fracture design. These solid particulate diverters (SPD) include low and high temperature systems that provide enhanced near-wellbore diversion in both case and open-hole applications. The SPD are designed to bridge across perforations and fractures in the higher permeability zones, diverting the stimulation fluid into lower permeability zones. A smaller sized multi-modal distribution of SPD controls the fluid in narrower natural fractures and wormholes, deepening penetration of the stimulation fluid along the entire fracture length. The SPD agents are fully degradable and do not contribute to permeability loss of the created fracture or the perforated interval when production starts. The production of the wells where the SPD agents were applied were higher in comparison to expected production of offset wells where non-acid crosslinked fracturing pad stages alternated with gelled or emulsified acid, and visco-elastic surfactant (VES) slugs. Both crosslinked fracturing pads, VES and emulsified acid slugs do not effectly control live acid leak off. Two case histories, documenting successes where this new approach to acid fracturing has been applied in the Tuba and Middle Marrat formations, have superior production results that correspond to enhanced fracture geometry.

Many neuropsychiatric conditions are primed or triggered by different types of stressors. The mechanisms through which stress induces neuropsychiatric disease are complex and incompletely understood. A ‘double hit’ hypothesis of neuropsychiatric disease postulates that stress induces maladaptive behavior in two phases separated by a dormant period. Recent research shows that the pleiotropic cytokine IL-6 is released centrally and peripherally following physical and psychological stress. In this article, we analyze evidence from clinics and animal models suggesting that stress-induced elevation in the levels of IL-6 may play a key role in the etiology of a heterogeneous family of hyperexcitable central conditions including epilepsy, schizophrenic psychoses, anxiety and disorders of the autistic spectrum. The cellular mechanism leading to hyperexcitable conditions might be a decrease in inhibitory/excitatory synaptic balance in either or both temporal phases of the conditions. Following these observations, we discuss how they may have important implications for optimal prophylactic and therapeutic pharmacological treatment.

Having an accurate model of the power curve of a wind turbine allows us to better monitor its operation and planning of storage capacity. Since wind speed and direction is of a highly stochastic nature, the forecasting of the power generated by the wind turbine is of the same nature as well. In this paper, a method for obtaining a robust confidence band containing the power curve of a wind turbine under test conditions is presented. Here, the confidence band is bound by two curves which are estimated using parametric statistical inference techniques. However, the observations that are used for carrying out the statistical analysis are obtained by using the binning method, and in each bin, the outliers are eliminated by using a censorship process based on robust statistical techniques. Then, the observations that are not outliers are divided into observation sets. Finally, both the power curve of the wind turbine and the two curves that define the robust confidence band are estimated using each of the previously mentioned observation sets.

To fracture unconventional reservoirs a different approach is required to be utilized. With the day-to-day advancement in fracturing technology more unconventional formations are being routinely fractured. But now and then we come across formations which challenge modern technologies and make us think out of box.This paper will describe the case history covering the planning and execution of one of the first "Acid-Frac" jobs in UAE. Being the first fracturing job in this formation, no previous stress gradient data was available nor were any leakoff test (LOT) or formation integrity test (FIT) results available at the planning stage. Various aspects of the reservoir and wellbore were considered, core samples of the formation were collected for testing and a 1-D mechanical earth model was developed. The paper will describe the steps taken to prepare the geological model along with the assumptions made. It will also discuss how the uncertainty of stress gradient was tackled while planning the job. Along with the unknown variables about formation, additional challenge was on the surface pressure limitation. Although tree-saver was planned to be used to protect the wellhead, the surface pressure limitation was due to wellbore completion. Based on the various unknowns and limitation on surface pressure, the job was designed. In addition to job planning, this paper will also discuss various lab tests which were conducted on the formation cores to optimally select acid fracturing fluid.Pre-job fracturing model was run with different scenarios which helped to predict if the job could be successfully pumped within the surface pressure limitation. Operation and equipment mobilization was optimized keeping in mind the uncertainties that were predicted. The paper will go into depth covering the different scenarios which were considered while planning the job, vital role of geological model and job execution. Although job execution did not go as per plan, paper will discuss various efforts which were made to establish injectivity and how this job helped in understanding the formation better learning lessons along the way which will be implemented in future campaigns.

SummaryThe natural response to itch sensation is to scratch, which relieves the itch through an unknown mechanism. Interaction between pain and itch has been frequently demonstrated, and the selectivity hypothesis of itch, based on data from electrophysiological and behavioral experiments, postulates the existence of primary pain afferents capable of repressing itch. Here, we demonstrate that deletion of vesicular glutamate transporter (VGLUT) 2 in a subpopulation of neurons partly overlapping with the vanilloid receptor (TRPV1) primary afferents resulted in a dramatic increase in itch behavior accompanied by a reduced responsiveness to thermal pain. The increased itch behavior was reduced by administration of antihistaminergic drugs and by genetic deletion of the gastrin-releasing peptide receptor, demonstrating a dependence on VGLUT2 to maintain normal levels of both histaminergic and nonhistaminergic itch. This study establishes that VGLUT2 is a major player in TRPV1 thermal nociception and also serves to regulate a normal itch response.

The economics of the oil and gas production requirements and advanceddrilling technologies are often pushing the length of horizontal well to newrecords. Gravel packing these very long horizontal wells present new challengesto completion operations. The combination of long horizontal sections ofunconsolidated formations, low fracture gradients and costly rig time are theother constraints that must be faced in the design and execution of asuccessful gravel packing completion offshore. Innovative technologies, optimized job design and planning are the keys for the success of packingjobs.This paper addresses several key factors that must be considered carefullyin installing a successful gravel pack completion. Pack completion requiresthat these low fracture gradient wells not be fractured during gravel placementto avoid excess leakoff and premature screenouts. The discussion includesvarious measures such as optimized screen wash pipe annulus and appropriateusing the differential valves, to effectively reduce frictional pressure duringBeta wave buildup. Fluid leakoff and leakoff control, in-situ gravelconcentration, and their relationship are also discussed. The gravelconcentration is dynamically changing through out the treatment based on theflow conditions in the wellbore, especially when the gravel starts to packaround screen. While most of the fluid travels down the screen-casing annulus, portion of the fluid leaks into formation, portion of the fluid diverges intothe screen-wash pipe annulus. The results may be an effective in-situ gravelconcentration higher than critical concentration, forcing gravel particledeposition to occur too soon and building up a premature bridge.Several job designs and application histories are also presented in thepaper to demonstrate the design considerations and valuable lessons learnt. Agroup of type curves are generated for a quick and easy check during joboperation, if any undesired condition is present, the operator can adjust theoperation and thus to avoid a job failure. The overall system of fluid dynamicsare discussed and treatment guidelines are presented to provide the CompletionEngineers the necessary information for designing successful treatments.