School Buildings in Rubble Stone Masonry With Cement Mortar in Seismic Areas: Literature Review of Seismic Codes, Technical Norms and Practical Manuals

A literature review was carried out with the aim to determine the current state-of-the-art with regards to non-engineered stone masonry in seismic areas. Specific search criteria and definitions were determined for school buildings with loadbearing walls of rubble stone masonry in cement mortar, nominally tied with horizontal reinforcements. A total of 47 relevant field manuals between 1972 and 2017 were analyzed for eligibility and checked for compatibility, initially with 109 national building codes. An overview was created of similarities, contradictions, gaps and differences between the publications. As the majority of the practical manuals target the Himalayan context, the most relevant codes for the comparison were the Indian and Nepali seismic and building codes. Only 9 manuals describe design and construction processes for schools, even though this conflicts with the codes which specifically prohibit the use of stone masonry for buildings with importance factor 1.5 or higher. It was noticed that 7 out of 9 manuals are (co-)written by the same author, and that the available knowledge, which is largely based on empirical evidence, can be traced back to just a few main sources. However, no consistency nor consensus was found on almost all key topics, such as main dimensions, openings and reinforcing elements. Also, the same illustrations and tables are copied over and over again, including apparent conflicts between the details. The fact that this has never been rectified, as well as the fact that the Indian and Nepali seismic codes have not been properly updated since 1994, are indications that the knowledge has not evolved much since the 1980's. It is concluded that the available information contains many contradictions and has become ambiguous. This raises questions about the correctness, reliability and actual value of the knowledge. The paper suggest that the existing knowledge must be fully assessed, validated, optimized and complemented by means of the current state-of-the-art for calculating, testing and modeling. To address this, the authors have started an initiative named SMARTnet, and make an appeal to experts and academics worldwide, to exchange their knowledge and to support the project with their time and expertise

Cost Analysis of Mountain Schools in Nepal: Comparison of Earthquake Resistant Features in Rubble Stone Masonry vs. Concrete Block Masonry

This paper analyzes the cost breakdown of earthquake resistant schools in Kaski District of Nepal, as built by Smart Shelter Foundation (SSF). Three types of designs are compared, which are rubble stone masonry with a wooden roof structure, and concrete block masonry with either a wooden roof or with a steel trussed roof. An in-depth cost analysis and cost comparison was carried out, based on a unique collection of local building prices from 19 different villages, as well as generally applicable District Rates, all spanning a period of 10 years between 2007 and 2017. Master Estimates were divided into the 5 main building phases of foundation, walls, roof, floor and finishing, and then further broken down into local costs for materials, labor, and transportation. These cost comparisons give a detailed insight in the distribution of the costs, the pricing of individual materials and construction elements, the effect of price fluctuation on the total costs, and the cost implications of different solutions for seismic measures. It is concluded that the market prices, especially of locally sourced materials, fluctuate too much, making it impossible to detect useful patterns for general application or future predictions. Also, no similarities were found between the local village rates vs. the general District Rates, which insufficiently reflect variations at the micro level, such as availability of materials, site accessibility, or local preferences. To address these issues, the paper introduces a helpful tool for rapid cost estimation of different school designs. The last chapter analyzes the price implications of adding or removing certain seismic features. It concludes that improving masonry with cement mortar has the highest cost impact, but that inclusion of important seismic features such as horizontal bands, buttresses, and steel bars is not that expensive, meaning there is basically no financial obstacle to incorporate these in new constructions of schools and houses. However, all interventions require in-depth technical and scientific validation, for which the authors have started an initiative named SMARTnet. The paper ends with an appeal to experts and academics worldwide, to exchange their knowledge and to support the project with their time and expertise

Experimental characterization and performance improvement evaluation of an electromagnetic transducer utilizing a tuned inerter

This research reports on the experimental verification of an enhanced energy conversion device utilizing a tuned inerter called a tuned inertial mass electromagnetic transducer (TIMET). The TIMET consists of a motor, a rotational mass, and a tuning spring. The motor and the rotational mass are connected to a ball screw and the tuning spring interfaced to the ball screw is connected to the vibrating structure. Thus, vibration energy of the structure is absorbed as electrical energy by the motor. Moreover, the amplified inertial mass can be realized by rotating relatively small physical masses. Therefore, by designing the tuning spring stiffness and the inertial mass appropriately, the motor can rotate more effectively due to the resonance effect, leading to more effective energy generation. The authors designed a prototype of the TIMET and conducted tests to validate the effectiveness of the tuned inerter for electromagnetic transducers. Through excitation tests, the property of the hysteresis loops produced by the TIMET is investigated. Then a reliable analytical model is developed employing a curve fitting technique to simulate the behavior of the TIMET and to assess the power generation accurately. In addition, numerical simulation studies on a structure subjected to a seismic loading employing the developed model are conducted to show the advantages of the TIMET over a traditional electromagnetic transducer in both vibration suppression capability and energy harvesting efficiency

Azuki Bean Juice Lowers Serum Triglyceride Concentrations in Healthy Young Women

Effects of azuki bean juice supplementation, prescribed according to a Kanpo medicine regimen, on serum lipid concentrations were studied. Healthy young Japanese women were recruited and were randomly assigned to one of the three groups using a parallel-group design. Control (n = 10), azuki (n = 11) and Concentrated azuki (CA) (n = 12) juice groups consumed 150 g daily of the isocaloric assigned juice for one menstrual cycle with their usual diet. Triglyceride concentrations were decreased in the azuki juice group (p<0.05) and tended to be decreased in the CA juice group (p = 0.055). Triglyceride concentrations in the azuki and CA juice groups decreased by 0.170 mmol/liter (15.4%) and 0.159 mmol/liter (17.9%), respectively (p<0.05). The azuki and CA juice used in this study inhibited pancreatic lipase activity 29.2% and 56.9%, respectively, in vitro. Lipid peroxide changes, based on ANCOVA with the initial level and α-tocopherol changes as covariates, did not differ among the three groups. Serum low density lipoprotein-cholesterol and high density lipoprotein-cholesterol (HDL) cholesterol concentrations did not change. Thus, azuki bean juice intake, as a traditional Kampo prescription, might be beneficial for preventing hypertriglyceridemia

Energy harvesting potential of tuned inertial mass electromagnetic transducers

The demand for developing renewable energy technologies has been growing in today\u27s society. As one of promising renewable energy sources, large-scale energy harvesting from structural vibrations employing electromagnetic transducers has recently been proposed and considerable effort has been devoted to increase the power generation capability. In this paper, we introduce the mechanism of a tuned inertial mass electromagnetic transducer (TIMET), which can absorb vibratory energy more efficiently by tuning the parameters to adjust the system. Then we propose a new vibratory energy harvester with the TIMET and determine the parameter values for the device with a simple static admittance (SA) control law to maximize the energy harvested from a stationary stochastic disturbance. To investigate the energy harvesting potential of the TIMET further, the performance-guaranteed (PG) control and the LQG control proposed in the literature are applied as well. Then the numerical simulation studies are carried out and the effectiveness of the proposed energy harvester is examined by comparing the traditional electromagnetic transducers

Adjustable vertical vibration isolator with a variable ellipse curve mechanism

This paper presents a passive vertical quasi-zero-stiffness vibration isolator intended for relatively small objects. The present isolator has features of compactness, long stroke, and adjustability to various load capabilities. To realize these features, we use constant-force springs, which sustain constant load regardless of their elongation, and propose a variable ellipse curve mechanism that is inspired by the principle of ellipsographs. The variable ellipse curve mechanism can convert the restoring force of the horizontally placed constant-force springs to the vertical restoring force of the vibration isolator. At the same time as converting the direction, the vertical restoring force can be adjusted by changing the ratio of the semi-minor axis to the semi-major one of the ellipse. In this study, a prototype of a class of quasi-zero-stiffness vibration isolator with the proposed variable ellipse curve mechanism is created. Shaking table tests are performed to demonstrate the efficacy of the present mechanism, where the prototype is subjected to various sinusoidal and earthquake ground motions. It is demonstrated through the shaking table tests that the prototype can reduce the response acceleration within the same specified tolerance even when the mass of the vibration isolated object is change

Near room temperature chemical vapor deposition of graphene with diluted methane and molten gallium catalyst

Direct growth of graphene integrated into electronic devices is highly desirable but difficult due to the nominal ~1000 °C chemical vapor deposition (CVD) temperature, which can seriously deteriorate the substrates. Here we report a great reduction of graphene CVD temperature, down to 50 °C on sapphire and 100 °C on polycarbonate, by using dilute methane as the source and molten gallium (Ga) as catalysts. The very low temperature graphene synthesis is made possible by carbon attachment to the island edges of pre-existing graphene nuclei islands, and causes no damages to the substrates. A key benefit of using molten Ga catalyst is the enhanced methane absorption in Ga at lower temperatures; this leads to a surprisingly low apparent reaction barrier of ~0.16 eV below 300 °C. The faster growth kinetics due to a low reaction barrier and a demonstrated low-temperature graphene nuclei transfer protocol can facilitate practical direct graphene synthesis on many kinds of substrates down to 50–100 °C. Our results represent a significant progress in reducing graphene synthesis temperature and understanding its mechanism

Feasibility of sliding base isolation for rubble stone masonry buildings in the Himalayan Mountain range

This paper studied the feasibility of a sliding base isolation layer to be used in rubble stone masonry buildings in rural areas in the Himalayan Mountain range to provide robust protection to important building like schools against strong earthquakes. In this paper, we carried out on-site investigations, quasi-static tests, and shaking table tests focusing on constructability as well as isolation performance. From the results of the feasibility study, the combination of styrofoam, concrete slab, and grease was found to be the most feasible to be used as the upper element, the lower element, and the lubricant, respectively, in the sliding isolation layer. The key features of the present sliding base isolation layer are: 1) the use of the materials that exist in rural mountain areas or those that can be easily transported from the neighboring towns and cities and 2) ease of construction and minimal change from the current construction practice. From the shaking table tests, we identified the conditions, e.g., grease amount, grease type, normal stress at the interface, and roughness of concrete slab surface, to achieve dynamic friction coefficients ranging from 0.08 to 0.16, suitable for sliding base isolation