Particulate polymer matrix composites (PPMCs) play a significant role in a wide range of applications from tissue engineering to aero-structures. Modeling thermoelastic properties of PPMCs can save ...sizable experimental time and costs, as it provides the capability of predicting the composite’s response to different loading conditions with acceptable accuracies. Micromechanical modeling approach is employed in this investigation to predict the thermoelastic properties of a new particulate polymer matrix composite, made of granite powder as inclusion and the acrylonitrile butadiene styrene (ABS) as matrix—called green stone composite. The reinforcing particles are modeled according to their shape irregularities. Namely, a statistical representative volume element (SRVE) is developed using the concept of integral range, with randomly distributed particles with irregular shapes. Experiments have been conducted to examine the validity of the proposed modeling approach. Numerical and experimental results both show that adding granite powder to pure ABS up to 38% (volume fraction) can notably increase the composite’s thermoelastic properties (bulk and shear moduli as well as thermal conductivity), as high as 200%.
New stone composite samples, fabricated using nano- to micro-sized recycled granite particles with irregular shapes and random distribution within a ABS matrix, demonstrate a highly nonlinear and ...complex fracture behavior. To model this behavior, a mixed mode cohesive zone finite element model is identified using the single-leg bending (SLB), in order to represent the granite particles-ABS interfacial debonding. An inverse methodology is then proposed to determine the parameters of the cohesive zone (CZM). A direct method based on J-integral approach is employed to determine the effective parameters of the traction-separation law. A two dimensional micromechanical extended finite element model (XFEM) of the composite is generated using X-ray micro-computed tomography (XMT) to mimic the actual shape of the particles. Finally, the identified cohesive model parameters have been employed to simulate the crack growth within the granite particulates/ABS composite. The comparison of the numerical and experimental results of the SLB test demonstrated the effectiveness of the proposed simulation framework.
Context
Ecosystem service bundles can be defined as the spatial co-occurrence of ecosystem services in a landscape. The understanding of the delivery of multiple ecosystem services as bundles in ...urban areas is limited. This study modelled ecosystem services in an urban area comprising the towns of Milton Keynes, Bedford and Luton.
Objectives
The objectives of this study were to assess (1) how ecosystem service bundles scale at a 2 m spatial resolution and (2) identify and analyse the composition of ecosystem service bundles.
Methods
Six ecosystem services were modelled with the InVEST framework at a 2 m resolution. The correlations between ecosystem services were calculated using the Spearman rank correlation coefficient method. Principal Component Analysis and K-means cluster analysis were used to analyse the distributions, spatial trade-offs and synergies of multiple ecosystem services.
Results
The results showed that regulating services had the tendency to form trade-offs and synergies. There was a significant tendency for trade-offs between supporting service Habitat quality and Pollinator abundance. Four bundle types were identified which showed specialised areas with prevalent soil erosion with high levels in water supply, areas with high values in nutrient retention, areas with high levels in carbon storage and urban areas with pollinator abundance.
Conclusions
This study demonstrates the existence of synergies and trade-offs between ecosystem services and the formation of ecosystem service bundles in urban areas. This study provides a better understanding of the interactions between services and improve the management choices in ecosystem service provision in urban and landscape planning.
Context
Landscape structure is thought to affect the provision of ecosystem service bundles. However, studies of the influence of landscape configuration on ecosystem service trade-offs and synergies ...in urban areas are limited. This study used Bayesian Belief Networks to predict ecosystem service trade-offs and synergies in the urban area comprising the towns of Milton Keynes, Bedford and Luton, UK.
Objectives
The objectives of this study were to test (1) a Bayesian Belief Network approach for predicting ecosystem service trade-offs and synergies in urban areas and (2) assess whether landscape configuration characteristics affect ecosystem service trade-offs and synergies.
Methods
Bayesian Belief Network models were used to test the influence of landscape configuration on ecosystem service interactions. The outputs of a Principal Component Analysis (PCA) on six ecosystem services and landscape configuration metrics were used as response and explanatory variables, respectively. We employed Spearman’s rank correlation and principal component analysis to identify redundancies between landscape metrics.
Results
We found that landscape configuration affects ecosystem service trade-offs and synergies. A sensitivity analysis conducted on the principal components showed that landscape configuration metrics core area (CORE) and effective mesh size (MESH) are strong influential determinants of ecosystem service trade-offs and synergies.
Conclusions
This study demonstrates that landscape configuration characteristics affect ecosystem service trade-offs and synergies and that a core set of metrics could be used to assess ecosystem service (ES) trade-offs and synergies. The findings may be relevant to planning and urban design and improved ecosystem management.
Introduction. To achieve a functional atraumatic cochlear implantation, intracochlear pressure changes during the procedure should be minimized. Postinsertional cable movements are assumed to induce ...intracochlear pressure changes. The aim of this study was to observe intracochlear pressure changes due to postinsertional cable movements. Materials and Methods. Intracochlear pressure changes were recorded in a cochlear model with a micro-pressure sensor positioned in the apical region of the cochlea model to follow the maximum amplitude and pressure gain velocity in intracochlear pressure. A temporal bone mastoid cavity was attached to the model to simulate cable positioning. The compared conditions were (1) touching the unsealed electrode, (2) touching the sealed electrode, (3) cable storage with an unfixed cable, and (4) cable storage with a fixed cable. Results. We found statistically significant differences in the occurrence of maximum amplitude and pressure gain velocity in intracochlear pressure changes under the compared conditions. Comparing the cable storage conditions, a cable fixed mode offers significantly lower maximum pressure amplitude and pressure gain velocity than the nonfixed mode. Conclusion. Postinsertional cable movement led to a significant pressure transfer into the cochlea. Before positioning the electrode cable in the mastoid cavity, fixation of the cable is recommended.
Context
Landscape connectivity is assumed to influence ecosystem service (ES) trade-offs and synergies. However, empirical studies of the effect of landscape connectivity on ES trade-offs and ...synergies are limited, especially in urban areas where the interactions between patterns and processes are complex.
Objectives
The objectives of this study were to use a Bayesian Belief Network approach to (1) assess whether functional connectivity drives ES trade-offs and synergies in urban areas and (2) assess the influence of connectivity on the supply of ESs.
Methods
We used circuit theory to model urban bird flow of
P. major
and
C. caeruleus
at a 2 m spatial resolution in Bedford, Luton and Milton Keynes, UK, and Bayesian Belief Networks (BBNs) to assess the sensitivity of ES trade-offs and synergies model outputs to landscape and patch structural characteristics (patch area, connectivity and bird species abundance).
Results
We found that functional connectivity was the most influential variable in determining two of three ES trade-offs and synergies. Patch area and connectivity exerted a strong influence on ES trade-offs and synergies. Low patch area and low to moderately low connectivity were associated with high levels of ES trade-offs and synergies.
Conclusions
This study demonstrates that landscape connectivity is an influential determinant of ES trade-offs and synergies and supports the conviction that larger and better-connected habitat patches increase ES provision. A BBN approach is proposed as a feasible method of ES trade-off and synergy prediction in complex landscapes. Our findings can prove to be informative for urban ES management.
The occurred changes in the earth are the most important historical transformations. It is a major opinion that the earth is not going to respond the human beings needs anymore, and we should think ...about the solutions. During the last decades, several meetings and seminars have been performed in this concern. But, unfortunately, none of the objectives have been achieved. The reason is that there is not any operative protection for the international laws and regulations. Hence, the countries and nations' authorities should include their accepted obligations within the international meetings in their domestic regulations, which contain a larger operative protection comparing the international ones. Iran is a country which contains special natural and environmental characteristics and is one of the first countries who play an important role in creating international environmental law. So, investigating this country domestic laws in comparison with the international environmental laws transformations will reflex its governors' viewpoints and strategies and the interaction between the internal and international law in this content. The existing research has been designed based on the results of the field studies which have been fulfilled in 20 provinces of Iran regarding the legal-environmental challenges resulted from the rules and regulation governing the forests, pastures and natural environment and their affected laws, and also, studies the ordinary and program laws of Iran applying the proving, comparative and critical methods. The studies show that, there are a large variety of ordinary law subjects which are not coordinated with international documents. Although, the international coordinated rules are centralized in government organizations which does not attract people participation and will not lead our society to a sustainable development. Therefore, it is necessary to inform people the values of natural resources and their interaction, while revising, improving and integrating the rules in this due to represent them in a unique complex.
•Heat pipe copper sheets (HPCS) for the battery thermal management system is designed.•A battery thermal management system is simulated and validated with experiments.•Temperature variation of a ...battery module in various initial conditions is reported.
This paper presents the concept of a hybrid thermal management system (TMS), including air cooling and heat pipe for electric vehicles (EVs). Mathematical and thermal models are described to predict the thermal behavior of a battery module consisting of 24 cylindrical cells. Details of various thermal management techniques, especially natural air cooling and forced-air cooling TMS are discussed and compared. Moreover, several optimizations comprising the effect of cell spacing, air velocity, different ambient temperatures, and adding a heat pipe with copper sheets (HPCS) are proposed. The mathematical models are solved by COMSOL Multiphysics®, the commercial computational fluid dynamics (CFD) software. The simulation results are validated against experimental data indicating that the proposed cooling method is robust to optimize the TMS with HPCS, which provides guidelines for further design optimization for similar systems. Results indicate that the maximum module temperature for the cooling strategy using forced-air cooling, heat pipe, and HPCS reaches 42.4 °C, 37.5 °C, and 37.1 °C which can reduce the module temperature compared with natural air cooling by up to 34.5%, 42.1%, and 42.7% respectively. Furthermore, there is 39.2%, 66.5%, and 73.4% improvement in the temperature uniformity of the battery module for forced-air cooling, heat pipe, and HPCS respectively.
Tractor operators are prone to neck and back discomfort and disorders. It is well known that awkward posture is a major contributor to this problem. Previous studies have investigated the prevalence ...of awkward posture and the resulting discomfort and disorders among tractor operators. They have also suggested various ways to mitigate this problem. With the introduction of new autosteer guidance systems, the tractor operator is relieved from the task of steering the tractor for most of the time during field work. Therefore, it is expected that the operator's posture will change. The goal of this study was to investigate the changes in the eye-glance behavior and posture of tractor operators as a result of using autosteer guidance systems. An eye-tracking system and a camcorder were used to record the eye-glance behavior and posture of 13 tractor operators as they performed seeding operations. The experiment with each operator consisted of two sessions. In one session, the operator used an autosteer system, while in the other session the operator steered the tractor manually. Analysis of the data showed that the eye-glance behavior and posture of the operators were significantly different between the autosteer and manual steering sessions. With the autosteer system, the operators spent less time in an awkward posture, and they changed their posture less frequently. However, even with the autosteer system, the operators spent 1/3 of their time in an awkward posture. Subjective feedback from the operators indicated that more than half of them experienced back or neck/shoulder discomfort during or after seeding. It is essential that the recommendations of the previous studies, such as using large rear-view mirrors or a rotating tractor seat, be evaluated when the operator is using an autosteer system. Other tools, such as video cameras that show the attached equipment, should also be tested to evaluate their effectiveness in reducing the operator's exposure to awkward postures.
A 69-year-old man presented for endoscopic examination of the upper gastrointestinal tract because of dysphagia for solid food and unintended weight loss. Several months before, he had noticed ...brownish-gray skin lesions in the neck, in the thorax and in both axillae. A dermatological consultant expressed the suspicion of a paraneoplastic disease. Endoscopic examination revealed an adenocarcinoma of the esophagogastric junction as well as multiple small polyps in the middle and the lower thirds of the esophagus. Histological examination showed papilloma-like proliferations without atypia, which were diagnosed as acanthosis nigricans of the esophagus. After completion of the staging investigation regarding the cardiac carcinoma, combination chemotherapy was started because of the presence of liver metastases. Subsequently, partial regression of the carcinoma as well as of the dermal and esophageal lesions was noted. Acanthosis nigricans is a rare paraneoplastic disease of the esophagus. As an indicator lesion, its detection should prompt a search for a malignant tumor in the gastrointestinal tract.
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