Investigation Of Ground Penetrating Radar For Detection Of Leaking Pipelines Under Roadway Pavements And Development Of Fiber-Wrapping Repair Technique

Nowadays, it has become a common practice to observe urban roadways undergo severe distress characterized by substantial depressions. In some cases, these pavement depressions are caused by leakages in the connecting joints of sewage pipelines laid beneath the roadway pavement. Manual inspection of pipe leakages has become costly and complex since sewage pipes with relative small diameters do not allow inspection from inside and digging may be required. On the other hand, pipes with large diameters, in which inspection can be made from pipe interior, inspector can not remain inside of the pipe for long periods of time because of toxic fumes. In order to overcome this problem, a geophysical technique known as ground penetrating radar (GPR) has been proposed as a candidate to detect the leakages. GPR is a nondestructive reflection technique, which uses high frequency electromagnetic waves to acquire subsurface information. GPR contributes to detect leaks in sewer pipes either by detecting underground voids surrounding the faulty pipe, or by detecting anomalies in the depth of the pipe as the radar propagation velocity varies due to the saturation of the soil near the leak. Once the leakage is detected, on site-repair technique to restore the damaged pipe is not an easy task. In this study, fiber reinforced polymer (FRP) composite created by saturating a fiber sheet with an epoxy resin matrix is proposed to be applied in several layers of overlay to the faulty structure surface. This fiber sheet is typically made of carbon or glass and saturated with the chemical resin matrix and makes the repaired structure even stronger than originally constructed. For the last twenty years, FRP has been used to repair and strengthen concrete columns by employing a practice known as fiber wrapping technique . This method involves the wrapping of unidirectional fiber composite sheets around concrete columns. FRP wrapping approach can be extended to sewage pipelines for repairing and strengthening the distressed pipeline. The purpose of this study is to detect leakages in sewer pipelines using GPR, and develop an on-site fiber-wrapping technique for repairing and strengthening sewage pipes. In detecting sewer leakages, one case study is presented. The case involves the use of GRP for leakage detection in a sewer pipeline overlaid by flexible pavement that already shows signs of subsidence. Moreover, in developing a repair technique, a gypsum cement mold wrapped with carbon fiber composite material is placed around a large-scale faulty pipe joint, and tested using a MTS servo-controlled hydraulic actuator. In addition, both free ends of the pipes are capped and filled with water to determine the effectiveness of the technique in stopping leaks along the repaired joint. During the GPR survey performed in the area of study, no clear indications of leakages were observed along the buried sewer pipeline. This lack of traceable signals from the subsurface was the result of the significant attenuation of the radar signal with depth that made impossible to discern effectively any anomaly along the designated pipeline. Although different antennas having center frequencies of 300 and 80 MHz were used and a variety of settings on the GPR unit were tried, the buried pipeline was barely detectable. Nevertheless, signal reflections generated by buried pipelines in other areas such as stormwater pipes on UCF campus and drainage pipelines at road side of University Boulevard were clearly detected, which makes to believe that the significant attenuation of the radar signal at the area of study is due to the extreme high conductivity of soils which have been severely contaminated by the leakage of sewage from the distressed pipeline. In contrast, favorable results were obtained in the development of the repair technique since the two-component system, Hydro-stone Gypsum Cement and FRP composite material, wrapped around the faulty joint effectively increased its structural capacity even higher than the pipe original strength

“El Turismo Rural como Modelo de Desarrollo Turístico y sus efectos ambientales en la Fundación María Cavalleri, Municipio de Matagalpa, Departamento de Matagalpa, durante el II Semestre 2009”

Se investigó el Turismo Rural como Modelo de Desarrollo Turístico y sus efectos ambientales en la Finca Agroecológica “Fundación María Cavalleri”, municipio de Matagalpa, departamento de Matagalpa, durante el II Semestre 2009. Con el propósito de analizar los efectos ambientales que genera el Turismo Rural en dicha finca. Las principales temáticas abordadas en esta investigación son: El Turismo Rural como Modelo de Desarrollo Turístico, Actividades de Turismo Rural en la Fundación María Cavalleri y Efectos que genera el Turismo Rural en el Medio Ambiente. Este estudio se realizó a través de entrevistas dirigidas a trabajadores de la Fundación María Cavalleri, giras de campo a la finca para la complementación y constatación de la información. Los aspectos más relevantes del estudio reflejan que El Turismo Rural se aplica como modelo de desarrollo turístico a rasgos generales en la Finca Agroecológica Fundación María Cavalleri, ya que se desarrolla en el medio rural debido a las condiciones físicas y geográficas de la misma. Por otro lado queda en manifiesto que el Turismo Rural crea conciencia turística en sus gestores y beneficiarios, así mismo innova en nuevas técnicas de producción sostenibles y, contribuye al rescate y conservación del Medio Ambient

Evaluación del coeficiente de conductividad y transmitancia térmica de elementos constructivos de tierra

O objetivo deste trabalho é determinar a condutividade térmica de diferentes elementos construtivos de terra produzidos com materiais característicos do centro-leste da província de Santa Fé (Argentina) e avaliar sua adequação para uso na construção de envelopes de edifícios que atendam aos requisitos de isolamento térmico dos regulamentos nacionais correspondentes. Para isso, foram feitos corpos de prova de acordo com as diferentes técnicas de construção com terra utilizadas na região (bloco de terra comprimida, adobe, tapia, quincha e gesso) e foi medido seu coeficiente de condutividade térmica, com o qual foi calculada a transmitância térmica de diferentes pacotes construtivos de terra. Os resultados obtidos indicam que as técnicas de construção com terra avaliadas apresentam, em todos os casos, melhor desempenho térmico do que as tradicionais paredes sólidas de tijolos cerâmicos ou blocos de concreto, sendo a quincha a técnica com maior capacidade de isolamento térmico.En este trabajo se pretende determinar la conductividad térmica de diferentes elementos constructivos de tierra producidos con materiales característicos del centro este de la provincia de Santa Fe (Argentina) y evaluar su aptitud para ser empleados en la construcción de envolventes que cumplan con los requerimientos de aislación térmica solicitados por la normativa nacional correspondiente. Para ello se confeccionaron probetas siguiendo las diferentes técnicas de construcción con tierra empleadas en la región (bloque de tierra comprimida, adobe, tapia, quincha y revoques) y se midió su coeficiente de conductividad térmica, con el cual se calculó la transmitancia térmica de diferentes paquetes constructivos de tierra. Los resultados obtenidos indican que las técnicas de construcción con tierra evaluadas presentan, en todos los casos, un mejor desempeño térmico que los tradicionales muros de ladrillo cerámico macizo o bloques de hormigón, siendo la quincha la técnica con mayor capacidad de aislamiento térmico.The aim of this work is to determine the thermal conductivity of different earthen constructive elements produced with materials typical of the central-eastern part of the Province of Santa Fe (Argentina), and to evaluate their suitability to be used in the construction of envelopes that comply with the thermal insulation requirements of the corresponding National Regulations. For this purpose, test specimens were made following the different earth construction techniques used in the region (compressed earth block, adobe, rammed earth (tapia), wattle and daub (quincha), and plaster), and their thermal conductivity coefficient was measured, with which the thermal transmittance of different earth construction packages was calculated. The results obtained indicate that the earth construction techniques evaluated show, in all cases, a better thermal performance than traditional solid ceramic brick or concrete block walls, with wattle and daub being the technique with the highest thermal insulation capacity

Compartmentation policies for Android apps:A combinatorial optimization approach

Some smartphone platforms such as Android have a distinctive message passing system that allows for sophisticated interactions among app components, both within and across app boundaries. This gives rise to various security and privacy risks, including not only intentional collusion attacks via permission re-delegation but also inadvertent disclosure of information and service misuse through confused deputy attacks. In this paper, we revisit the perils of app coexistence in the same platform and propose a risk mitigation mechanism based on segregating apps into isolated groups following classical security compartmentation principles. Compartments can be implemented using lightweight approaches such as Inter-Component Communication (ICC) firewalling or through virtualization, effectively fencing off each group of apps. We then leverage recent works on quantified risk metrics for Android apps to couch compartmentation as a combinatorial optimization problem akin to the classical bin packing or knapsack problems. We study a number of simple yet effective numerical optimization heuristics, showing that very good compartmentation solutions can be obtained for the problem sizes expected in current’s mobile environments

Feelings of contrast at test reduce false memory in the Deese/Roediger-McDermott paradigm

False memories in the Deese/Roediger-McDermott (DRM) paradigm are explained in terms of the interplay between error-inflating and error-editing (e.g., monitoring) mechanisms. In this study, we focused on disqualifying monitoring, a decision process that helps to reject false memories through the recollection of collateral information (i.e., recall-to-reject strategies). Participants engage in recall-to-reject strategies using one or two metacognitive processes: (1) applying the logic of mutual exclusivity or (2) experiencing feelings of contrast between studied items and unstudied lures. We aimed to provide, for the first time in the DRM literature, evidence favorable to the existence of a recall-to-reject strategy based on the experience of feelings of contrast. One hundred and forty participants studied six-word DRM lists (e.g., spy, hell, fist, fight, abduction, mortal), simultaneously associated with three critical lures (e.g., WAR, BAD, FEAR). Lists differed in their ease to identify their critical lures (extremely low-BAS lists vs. high-BAS lists). At recognition test, participants saw either one or the three critical lures of the lists. Participants in the three-critical-lure condition were expected to increase their monitoring, as they would experience stronger feelings of contrast than the participants in the one-critical-lure condition. Results supported our hypothesis, showing lower false recognition in the three-critical-lure condition than in the one critical-lure condition. Critically, in the three-critical-lure condition, participants reduced even more false memory when they could also resort to another monitoring strategy (i.e., identify-to-reject). These findings suggest that, in the DRM context, disqualifying monitoring could be guided by experiencing feelings of contrast between different types of words

Homework motivation and engagement throughout compulsory education

The present investigation examines changes in students' homework engagement and motivation as they advance to higher grade levels in Spanish compulsory education. The study takes into account the possible effect of prior academic achievement on students' homework engagement and motivation. Participants included 1257 students (ranging in age from 9 to 16 years) from four regions in northern Spain. Results show that: (a) There are statistically significant differences in students' homework engagement and motivation as they advance to higher grade levels; and (b) Students' prior academic achievement is related to their homework engagement and motivation.info:eu-repo/semantics/publishedVersio

Hindering data theft with encrypted data trees

Data theft is a major threat for modern organizations with potentially large economic consequences. Although these attacks may well originate outside an organization’s information systems, the attacker—or else an insider—must even-tually make contact with the system where the information resides and extract it. In this work, we propose a scheme that hinders unauthorized data extraction by modifying the basic file system primitives used to access files. Intuitively, our proposal emulates the chains used to protect valuable items in certain clothing shopping centers, where shoplifting is prevented by forcing the thief to steal the whole rack of items. We achieve this by encrypting sensitive files using nonces (i.e., pseudorandom numbers used only once) as keys. Such nonces are available, also in encrypted form, in other objects of the file system. The system globally resembles a distributed Merkle hash tree, in such a way that getting access to a file requires previous access to a number of other files. This forces any potential attacker to extract not only the targeted sensitive information, but also all the files chained to it that are necessary to compute the associated key. Further-more, our scheme incorporates a probabilistic rekeying mechanism to limit the damage that might be caused by patient extractors. We report experimental results measuring the time overhead introduced by our proposal and compare it with the effort an attacker would need to successfully extract information from the system. Our results show that the scheme increases substantially the effort required by an insider, while the introduced overhead is feasible for standard computing platforms

Detecting Targeted Smartphone Malware with Behavior-Triggering Stochastic Models

none4sinoneGuillermo Suarez-Tangil; Mauro Conti; Juan E. Tapiador; and Pedro Peris-LopezGuillermo Suarez, Tangil; Conti, Mauro; Juan E., Tapiador; Pedro Peris, Lope