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The microstructure of a heterogeneous high explosive (HE) affects its shock initiation sensitivity and detonation performance. Alteration of the void content and/or void structure (i.e. bulk heating or mechanical damage) therefore changes the shock initiation behavior. Controlling and predicting the change in shock sensitivity after an HE has undergone microstructural changes addresses an important and challenging goal for the design and understanding of novel energetic material formulations. In this study, we aimed to develop HE systems to precisely tune shock sensitivity by a thermal treatment prior to use. Specifically, we incorporated a small fraction (1 wt% or less) of thermally expandable microspheres (TEMs) during the formulation process of various plastic-bonded explosives (PBX). TEMs typically consist of a thermoplastic acrylonitrile shell (10-50 µm diameter), which encapsulates an inert low boiling hydrocarbon. Upon heating, the TEMs expand as the shell softens while the hydrocarbon gasifies, increasing the internal pressure and expanding the particle by as much as 120 vol% (irreversibly). Here, we present our progress on shock sensitivity comparisons of HE formulations doped with TEMs after heating and expansion. Experiments, using Composition C-4 thermally-cycled to 120 °C, showed an increase in shock sensitivity. Mesoscale modeling revealed that the TEM itself does not act as a hotspot, but instead has a secondary effect on the response of nearby voids. We conclude that TEMs indeed do provide a method to tune shock sensitivity. Further, our results emphasize the non-uniformity of shock waves at the mesoscale, and that upstream defects influence the reactivity of downstream defects. [ABSTRACT FROM AUTHOR]

This article presents the results of research on the effect of superficial strengthening with the FRCM system on the shear strength of clay brick samples. The main purpose of the research was to determine, in accordance with the PN-EN 1052- 3 standard, the initial and the characteristic shear strength of the wall. The intermediate goals were to observe behaviour, cracking pattern, method of destruction of research elements. The research program included three series of 6 models each, consisting of elements without any strengthening, strengthened at one or both sides. The models were made using clay masonry units, class 35 and lime-trass mortar class M5. Models were strengthened on one and two sides with the FRCM system, using the mineral cement matrix PBO-MX GOLD MASONRY and the PBO-MESH GOLD 22/22 mesh. During the test, in addition to recording the load, the displacements between the masonry elements were measured using the Aramis system and LVDT sensors. Both in the case of strengthened on one or both sides of the models, a significant increase in shear strength was noted and a ductile method of sample destruction compared to models without strengthening. [ABSTRACT FROM AUTHOR]

Because of the infrastructure's growing degradation, which is usually accompanied with the necessity for structural upgrading due to the structure's change in functioning, Retrofitting is becoming more and more important and receives today considerable emphasis throughout the worlds. Retrofitting is an action that improves future performance by adjusting the structure or design of a structure or its components. Retrofitting is required to make structure earthquake-resistant. Retrofitting is preferred over destruction and reconstruction since it is often less expensive. In this paper, base shear capacities and displacements of RC building with and without retrofitting is analysed and compared in ETAB software. Two types of retrofitting techniques were used i.e., Steel Jacketing and RC Jacketing, to strengthen the structural members. Non-linear static analysis was carried out and the result shows that there is an increment in the Base shear capacity and the maximum displacement where failure takes place. [ABSTRACT FROM AUTHOR]

In recent two decade, researchers are working on new emerging area Bio-gio engineering. Microbialy Induced Carbonic Precipitation method is getting popularity because of its sustainability, feasibility, eco friendly nature and economy as compared to the other mechanical and chemical ground improvement techniques. This research is focused on optimal use of two important input variables, retention time and chemical concentration to induce CaCO3 precipitation in open environments using Bacillus Sphaericus. Most of the studies on bio mineralization are done with microbe Sporosarcina pasteurii,we have used microbe Bacillus Sphaericus for optimisation in Indian context. To optimize the retention time and chemical concentrations,different combinations of injections and chemical concentrations were tried and precipitated in porous sand media to achieve the required density and to access the optimize pumping rate for bio mineralization. Results showed that,the input rate of 0.1Molar,0.25Molar and 0.5Molar liquid media input can be optimized to 0.04M/L/H to get higher and homogeneous precipitaton. The concentration of liquid solution in the input could be as high as 1 Molar and as low as required,depending upon number of injections. The performance efficiency was homogeneous through different cementation stages upto precipitation value of 0.03gm/gm of sand (i.e.3%). The efficiency was decreased as moving towards the higher molar solution. The optimized values for experimental factors were calculated and discussed. [ABSTRACT FROM AUTHOR]

Presence of footings near slope fill occurs quite frequently. In order to shed lights on this problem, a sequence of tests was performed into the performance of footing adjacent to sand slope. The experiments contained a laboratory testing program conducted small scale footing located near a slope sand fill. The testing model was designed and manufactured to be able for investigating the influence of selected parameters on the footing behavior. The parameters included in this work are the shape of footing, depth of footing, and distance between slope crest and foundation edge on the load carrying capacity of foundation. The stated results showed that with increasing the footing area by 50% the load carrying capacity increases 12% while for 100% area enlarge, 29% of load carrying capacity was recorded. It can be concluded that when d/B ratio ranges from 0 to about 0.25, there is no considerable effect on the footing bearing capacity. Moreover, the outcomes of the experimental study show that the footing's bearing capacity improves with increasing the distance between the slope crest and foundation to the width of foundation ratio. This increase ends when b/B ratio reaches 2.5. [ABSTRACT FROM AUTHOR]

In this work a new point of view to evaluate prediction models is presented. It is captured by mean of a novelty dissimilarity measure among time series, the Temporal Distortion Index (TDI), which compiles a new methodology to evaluate and control the solar radiation prediction models. This methodology complements the traditional verification measures found in the literature by adding the evaluation of the impact that time misalignments produces in the forecast accuracy. This new measure of error will allow a deeper knowledge of the prediction model behaviour besides a bicriteria perspective to the problem of comparing different forecasts. The information about temporal features of the forecasts could play a key role in tasks as combination of different prediction models, Concentrating Solar Power (CSP) plants operation or energy grid integration. [ABSTRACT FROM AUTHOR]

Ceramic matrix composites are composite materials with ceramic fibers in a high temperature matrix of ceramic or glass-ceramic. This emerging class of materials is viewed as enabling for efficiency improvements in many energy conversion systems. The key controlling property of ceramic matrix composites is a relatively weak interface between the matrix and the fiber that aids crack deflection and fiber pullout resulting in greatly increased toughness over monolithic ceramics. United Technologies Research Center has been investigating glass-ceramic composite systems as a tool to understand processing effects on material performance related to the performance of the weak interface. Changes in the interface have been shown to affect the mechanical performance observed in flexural testing and subsequent microstructural investigations have confirmed the performance (or lack thereof) of the interface coating. Recently, the addition of acoustic emission testing during flexural testing has aided the understanding of the characteristics of the interface and its performance. The acoustic emission onset stress changes with strength and toughness and this could be a quality tool in screening the material before further development and use. The results of testing and analysis will be shown and additional material from other ceramic matrix composite systems may be included to show trends. [ABSTRACT FROM AUTHOR]

Type-IV pressure vessels are increasingly being applied for hydrogen storage purposes in mobile and stationary applications. Due to manufacturing defects in the wet filament winding process these pressure vessels currently have to be oversized beyond the legal safety factor of 2.25, which requires high avoidable costs. With the aim of reducing the costs and weight of type-IV pressure vessels, the Institute for Plastics Processing (IKV) is developing a quality assurance system with location-resolved data visualisation in the form of a digital twin of pressure vessels, whereby process-induced defects can be detected. Against this background, this publication shows insights into the change of defects in the form of gaps and overlaps between neighbouring fibre bands after the curing process and quantifies their influence on the mechanical properties of ring test specimens. The extent of the defect is determined during the process by using the authors' optical measuring systems. Afterwards, the effect of defects on the tensile strength is analysed by using the split-disc-test-method. It is shown that all intentionally introduced defects can no longer be clearly distinguished by means of microscopical analysis from the rest of the laminate after the curing process. In the mechanical tests, the effect of gaps and overlaps on the tensile strength of ring test specimens varies in terms of direction and extend. [ABSTRACT FROM AUTHOR]

The studies mechanical characteristics of wood the dowel nest and deformation characteristics of the material of the dowel for joints of wooden structures on plates with cylindrical dowels TGk [1]. The relevance of the study is due to the lack of experimental and theoretical data on the mechanical characteristics of the wood of the dowel nest and the material of the dowel for connections on TGk dowel plates. The article presents the results of a sufficiently large sample of experimental studies of the mechanical characteristics of the dowel nest wood for a dowel diameter of 5 mm, carried out using a short die with a cylindrical contact surface. On the basis of the received data the statistical analysis of all t est results according to the definition of resistance to buckling of dowel nest Rcr.n and resistance to compression Rz of all set of the used wood is carried out. The results are also given to determine the experimental data of the mechanical characteristics of the dowel material, which were determined by bending the concentrated load of a single dowel with a diameter of 5 mm, welded to the plate. The aim of the research is to obtain a short-term diagram of the deformation of the wood of the dowel nest in the working range for making accurate calculations of the joints of wooden structures on TGk connecting plates; to determine and compare the strength and deformation characteristics for a free dowel and a dowel welded to the plate by means of resistance welding. [ABSTRACT FROM AUTHOR]

The usage of traditional high-performance computing (HPC) is a challenge for scientific workflows because of the high cost of acquisition and a lack of expertise to deploy and support such in-house infrastructures. HPC as a Service cloud model has tremendous potential of spreading the outreach of HPC to the broader scientific and industrial community considering the advantages of elasticity, flexibility, and customization. The mismatch between performance-oriented HPC and cost and resource-utilization oriented cloud an infrastructure is an additional barrier to build a cloud-based optimized HPC environment. Therefore, we aim to provision HPC capabilities over the cloud, combining scientific discoveries in cloud data fusion, algorithms, methods, and SaaS through comprehensive performance and energy efficiency analysis. [ABSTRACT FROM AUTHOR]

The development of large-scale reinforced concrete (RC) structures, such as high-rise skyscrapers, long-span bridges, and nuclear power plants, has grown dramatically in recent decades. The cross -sections of members expand when the constructions become taller and larger in scale. These massive components necessitate an excessive amount of concrete and steel reinforcement, resulting in a hefty self-weight and costly structure. Many investigators have been interested in find ing ways to better employ high-strength materials in order to minimize excessive use of build ing materials and have performed numerous research studies. Since the shear strength pred iction of RC members without transverse reinforcement is an essential criterion in the design of concrete beams and frames. Besides that, many concrete structural members which inc lud ing slabs, walls, and foundations do not use stirrups, so a better understand ing of the shear strength of RC members without transvers e reinforcement is also considered necessary in these cases. However, even with sophisticated analytical tools, accurate prediction of the shear behavior of RC members continues to be a significant task. Because of the complexity of the shear transmission mechanism in RC and the absence of appropriate models for the many activities that can contribute to shear transfer, so it is important to investigate the impact of size on the shear behavior of RC structural elements. [ABSTRACT FROM AUTHOR]

The increasing volume of waste in nature will reduce the quality of the environment, therefore necessary to find the solution. One way to utilize waste is used as a stabilizing agent of clay. Soil stabilization is one method of soil improvement to increase capacity and decrease soil compressibility. In this study focused the effects of stabilization of clay with 15% Calcium Carbide Residue (CCR), 30% trass and 1% of waste plastic fiber to determine behavior load-settlement with the variations in dimension of footing 20cm × 20cm, 20cm × 30cm, 20cm × 40cm, 30cm × 30cm, 30cm × 40cm, 40cm × 40cm and the stabilization layer thickness variation 2.5cm, 5cm, 7.5cm, and without stabilization. Tests were carried out in the laboratory using a test box. The research showed that in all various footing dimensions with the stabilization layer can increase the ultimate bearing capacity of footing compared to the footing on unstabilized clay soil. Increasing thickness of the layer of stabilization was increased the ultimate bearing capacity/bearing pressure of footing with improvement factor (If) value of 1.33-4.69, Percentage Reduction Settlement (PRS) value of 43.08%-91.89%, the factor of modulus subgrade equivalent (FMSE) value of 2-58. [ABSTRACT FROM AUTHOR]

The Singular Spectrum Analysis (SSA) forecasting method has been used widely recently. SSA has characteristics and advantages in decomposing data into trends, oscillations, and noise, which are for forecasting. Forecasting withSSA can be done by several ways e.g. Linear Recurrent Formula (LRF), Vector, and Simultaneous. The Bootstrapping process is implemented in those forecasting methods to increase the accuracy and builds the interval forecast. This study focuses on testing the sensitivity and accuracy of the combination of the Bootstrap-LRF and Bootstrap-Vector methods. The tests are applied to data that contains structural breaks, namely Indonesia's trade monthly data (exports and imports) from 1993 to 2019. The test results show that Bootstrap-Vector has a smaller forecasting range and is more accurate than Bootstrap-LRF in long-horizon forecast. Moreover, the Bootstrap-Vector is more stable in the presence of structural break in the data, meaning that this method is less sensitive to structural changes. Meanwhile, Bootstrap-LRF is more accurate in short horizon forecast. [ABSTRACT FROM AUTHOR]

The study presents the improvement design of a post that used for traffic safety barrier. The aim of this investigation is to conceptualise and design a rooted guard rail post. It is then comparatively analyse and investigated over the existing posts based on their standard parameters. The selected design was tested by finite element analysis simulations using SolidWorks which focuses on the deflection of the post. The study shows that, the proposed rooted-post was able to withstand much higher horizontal impact force as compared to existing types of W-Beam Post, and Wire Rope Post. It also proves that, the root of the post is able to significantly increase the soil-post interaction which helps the pole to withstand a much greater impact during accidents. In conclusion, the design of proposed post has better performance which is expected to reduce the run-off-road catastrophic accidents. [ABSTRACT FROM AUTHOR]

Covariance matrices have advantages to classify series for time series classification. The series is segmented into subsequences that its feature points are adopted as the vector. Covariance matrices can capture the pairwise correlation between feature vectors. After feature extraction, the next step is the classification process. Our primary purpose is to evaluate the feature covariance matrices with kNN (Cov-kNN) under simulation pattern and UCR time series data sets by optimal neighborhood and interval. The CovNN also is compared in this work. Our results that both algorithms have comparable performance. So that, using Cov-kNN and separating series to several intervals is considered. [ABSTRACT FROM AUTHOR]

A comprehensive study of optical and mechanical properties of quartz glass (fused silica) with regard to application in high temperature solar receivers is presented. The dependence of rupture strength on different surface conditions as well as high temperature is analyzed, focussing particularly on damage by devitrification and sandblasting. The influence of typical types of contamination in combination with thermal cycling on the optical properties of fused silica is determined. Cleaning methods are compared regarding effectiveness on contamination-induced degradation for samples with and without antireflective coating. The FEM-aided design of different types of receiver windows and their support structure is presented. A large-scale production process has been developed for producing fused silica dome shaped windows (pressurized window) up to a diameter of 816 mm. Prototypes were successfully pressure-tested in a test bench and certified according to the European Pressure Vessel Directive. [ABSTRACT FROM AUTHOR]

The article discusses the implementation of the requirements of the new version of the international standard ISO/IEC 17025:2017 in.the test laboratory in the transition period from the old version of 2007. The requirements for validation and verification of methods, calculation of uncertainty of measurements have different interpretations on the part of interested parties, therefore, the article interprets these requirements based on the recommendations of international organizations. As an example, the verification of food methods is considered. The data obtained were processed taking into account the recommendation of international standards. According to the requirements, verification of any object, process or service must meet its purpose and intended use, that is, solve the specific tasks of the customer who acquires them. The process of production and sale of food products (for example, yogurt, milk, dairy products, confectionery products, etc.) must be sterile and safe, meeting the requirements of technical specifications; Food technology should be done carefully, professionally, according to hygienic rules, taking into account the individuality of the customer. Based on the data obtained, a number of recommendations and conclusions have been developed that are of practical interest to all participants in assessing food conformity. [ABSTRACT FROM AUTHOR]

The paper is about intensification and energy saving in the separation processes of liquid mixtures. Authors consider the implementation of thermal rectification in heat-mass exchange apparatuses using internal condensers. A new contact device with inclined plates and internal pipes was developed. The research aimed to determine the hydraulic resistance of the designed contact device under various heat-and-mass transfer apparatus operating regimes. Two series of experiments in the heat-mass exchange apparatus with developed contact devices were conducted with and without the advanced contact surface in the form of a mesh metal grid. The dependences of pressure drop for wet/dry contact devices with inclined plates and internal pipes at different wetting rates were plotted. The presented dependencies make it possible to consider changes in the physicochemical properties of working fluids at various pressures and temperatures. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) for syngas production was studied in a dielectric barrier discharge (DBD) plasma reactor at atmospheric pressure. The influences of various operating parameters such as total feed gas flow rate (0.18 – 1.6 L min−1), input power (10 – 130 W), and feed ratio of CO2/CH4 (1-7) on the CO2 and CH4 (reactant) conversions, syngas selectivity, yield, and syngas ratio (H2/CO) were investigated. Experimental results indicated that the highest conversions of CH4 (81.24 %) and CO2 (48.67 %) were obtained with the feed gas flow rate of CH4:CO2:N2 of 0.3:0.3:1.0 L min-1 and the input power of 10 W. At these input conditions, the highest H2 and CO yield of 44.13 and 36.15 % were also achieved respectively. It was found that the syngas ratio was insignificantly promoted with the increment of the total feed flow rate while it declined when rising input power and the input CO2/CH4 ratio. [ABSTRACT FROM AUTHOR]

Cricket is an outdoor game which is highly common and extremely followed in Asia. This game has a huge fan following across the globe. There are three formats of playing Cricket. The challenges posed by each format is different from other. When two equally skilled teams clash, the outcome of the cricket match becomes highly unpredictable. Each team comprises of eleven members and the collective effectiveness of a team determines its win.This work is focused towards performing a thorough review of the various approaches and techniques that are deployed across the game of cricket and how they are instrumental in predicting the outcome of the game. Also a basic prediction model that uses classifiers like Support Vector Machines (SVM), Decision Tree and Random Forest. [ABSTRACT FROM AUTHOR]

The paper investigates the effect of nanocomposite coatings on centrosymmetric bending strength σbB and light transmission factor in visible band of a glass specimens. The coatings on the basis of Al-Si-N and In-Sn-O systems deposited on the surface of quartz specimens (KV grade) using pulsed magnetron sputtering. The deposition of In-Sn-O coating on the glass more prominently, ∼1.6 times, increases the value of σbB as compared to ∼1.3 times which is typical for Al-Si-N coating. Coatings based on In-Sn-O more effectively increased the cracking resistance of quartz glass. [ABSTRACT FROM AUTHOR]

In the field of deep drawing with compliant tools, there are high numbers of variants that influence the process. They are all based on the same concept, to eliminate one of the fixed tool halves, meaning that one of the shaping contours can be replaced by using a rubber pad. The advantage of this method lies for small series production, since the manufacturing cost of these tools is lower by nearly 30% compared to conventional deep drawing tools. Yet, one disadvantage is the short life time of the rubber pad, which must be replaced completely, when worn out. This article presents the concept of a modular rubber pad tool for deep drawing sheet metal blanks. A feasibility analysis presents the achieved results. This paper also shows the potential savings for small-series production with adherence of the consistent quality of the parts. The modular structure reduces maintenance work as well, since it must not be replaced completely due to wear. [ABSTRACT FROM AUTHOR]

The cryogenic transfer line for KATRIN connects 3 large superconducting magnet systems in the Tritium Laboratory Karlsruhe (TLK) with a He refrigerator installed in an external machine building. The vacuum-insulated transfer line comprises 1 N2 and 5 He process lines that are surrounded by a LN2-cooled radiation shield. Covering a distance of 40 m, the transfer line includes 4 valve boxes, 1 T-junction, 1 vertical and 3 horizontal line sections. After the introductory system description, an overview is given on project coordination and quality assurance, together with results of leak testing during pre-acceptance and commissioning. The method and results of thermal loss measurements in the He system are explained, reaching an accuracy of ±30% with standard process instrumentation. Potential improvements in the MLI insulation scheme are revealed, based on both the measurements and theoretical considerations. The experimental results are finally compared with data of large cryogenic transfer systems. [ABSTRACT FROM AUTHOR]

One of the current challenges facing researchers in the field of dynamic properties of materials is the need for a predictive modeling capability for damage and fragmentation. A series of small-scale, explosively-driven experiments were designed and executed in order to gain a better understanding of the nucleation and growth of damage under explosive loading. The interaction of varying obliquity detonation waves with the test articles was of particular interest. The material in these tests experiences a combination of hydrostatic and deviatoric stresses that is spatially and temporally varying. Variations in shot geometries and explosive load causes direct variations in the nature of the resulting damage fields in the recovered samples. The characterization of a number of samples from a test series of tantalum discs will be presented and compared to numerical analyses of the experiments. Insights gained from the post-mortem examination of the discs and the accompanying simulations will be presented. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]

The ‘Herschel Space Observatory’ is the fourth cornerstone mission in the European Space Agency (ESA) science program. Herschel will be placed in an operational orbit around the Earth-Sun L2 point by an Ariane 5 in early 2007 to perform measurements in the wavelength range from 60 to 670 micrometers during its operational lifetime of 3.5 years. The cold environment for the instruments is provided by the evaporation of superfluid helium. The thermo-mechanical effect in a porous plug is used for the in-orbit separation of liquid and gaseous phase under zero gravity conditions. The required dynamic range of the Passive Phase Separator (PPS) is defined by the expected post-launch mass flow rate and bath temperature variations between 1.5 and 20 mg/s and 1.5 and 2.1 K, respectively. Measurement results concerning mass flow rate, bath temperature, temperature difference across the porous plug and pressure drop were gained in the development phase of the porous plug. As a side effect, an unexpected behavior of the temperature difference over the porous plug near the liquid break-through temperature was observed. The measured characteristics of the selected flight plug are evaluated in the context of system level thermal and pressure drop analysis. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

A key element of space launch vehicles and systems is thermal insulation for cryogenic tanks and piping. Glass microspheres, or glass bubbles, represent an alternative insulation material for a number of applications. Composite materials and engineered thermal insulation systems are also being developed based on the use of glass bubbles as the main constituent material. Commonly used materials, such as spray-on foam insulation, or SOFI, for vehicle tanks and perlite powder for ground storage tanks, are targeted for replacement with the new-technology systems that use glass bubbles. Complete thermal characterization of the glass bubbles is the first step toward producing the engineering solutions required for the energy-efficient, low-maintenance cryogenic systems of the future. Thermal performance testing of the glass microsphere material was successfully completed at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The test measurements were made at the full temperature difference (typical boundary temperatures of 78 kelvin [K] and 293 K) and included the full cold-vacuum pressure range. The results are reported in apparent thermal conductivity (k-value) and mean heat flux. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

High-temperature superconducting (HTS) cables that typically operate at temperatures below 80 kelvin (K) are being developed for power transmission. The practical application of HTS power cables will require the use of flexible piping to contain the cable and the liquid nitrogen coolant. A study of thermal performance of multilayer insulation (MLI) was conducted in geometries representing both rigid and flexible piping. This experimental study performed at the Cryogenics Test Laboratory of NASA Kennedy Space Center provides a framework for the development of cost-effective, efficient thermal insulation systems that will support these long-distance flexible lines containing HTS power cables. The overall thermal performance of the insulation system for a rigid configuration and for a flexible configuration, simulating a flexible HTS power cable, was determined by the steady-state liquid nitrogen boiloff method under the full range of vacuum levels. Two different cylindrically rolled material systems were tested: a standard MLI and a layered composite insulation (LCI). Comparisons of ideal MLI, MLI on rigid piping, and MLI between flexible piping are presented. [ABSTRACT FROM AUTHOR]

Flexible, vacuum-insulated transfer lines for low-temperature applications have higher thermal losses than comparable rigid lines. Typical flexible piping construction uses corrugated tubes, inner and outer, with a multilayer insulation (MLI) system in the annular space. Experiments on vacuum insulation systems in a flexible geometry were conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. The effects of bending were simulated by causing the inner tube to be eccentric with the outer tube. The effects of spacers were simulated in a controlled way by inserting spacer tubes for the length of the cylindrical test articles. Two material systems, standard MLI and a layered composite insulation (LCI), were tested under the full range of vacuum levels using a liquid nitrogen boiloff calorimeter to determine the apparent thermal conductivity (k-value). The results indicate that the flexible piping under simulated bending conditions significantly degrades the thermal performance of the insulation system. These data are compared to standard MLI for both straight and flexible piping configurations. The definition of an overall k-value for actual field installations (k[sub oafi]) is described for use in design and analysis of cryogenic piping systems. [ABSTRACT FROM AUTHOR]

In order to apply the mechanical properties (measured on material specimens or laboratory-sized models) to large structures (such as concrete dams), a nonlinear theory able to predict the size-scale effect has to be used. One of these theories was first proposed by Hillerborg and co-workers (fictitious crack model) and is based on the previous works of Barenblatt and Dugdale for metals (cohesive crack model). It is based on the existence of a Fracture Process Zone (shortened FPZ), where the material undergoes strain softening. The behaviour of the material outside the FPZ is linear elastic. A large number of short time laboratory tests were executed, by varying the load, under CMOD control. Since concrete exhibits a time-dependent behaviour, an interaction between creep and micro-crack growth occurs in the FPZ. Therefore a different testing condition can be applied: rupture can be achieved by keeping the load constant before peak value (pre-peak tests), or after peak value and after an unloading and reloading procedure (post-peak tests). The crack propagation rate is shown to be small enough to neglect inertial forces and large enough to keep the time-dependent behaviour of the process zone as dominant compared to the behaviour of the undamaged and viscoelastic zone. Due to the variability in material microstructure from one specimen to another, experimental data show large ranges of scatter. Well established methods in probability theory require sufficient experimental data in order to assume a probability density distribution. For situations where the values of the material parameters are of a non-stochastic nature, the fuzzy-set approach to modelling variability has been proposed as a better and more natural approach. To investigate the ranges of variation of the time response under constant load of simple structural elements associated with pre-selected variation (fuzziness) in the main material parameters is the objective of the present study. [ABSTRACT FROM AUTHOR]

The use of resistance heaters to simulate heat from fission allows extensive development of fission systems to be performed in non-nuclear test facilities, saving time and money. Resistance heated tests on the Module Unfueled Thermal-hydraulic Test (MUTT) article has been performed at the Marshall Space Flight Center. This paper discusses the results of these experiments to date, and describes the additional testing that will be performed. Recommendations related to the design of testable space fission power and propulsion systems are made. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Serial production of superconducting (SC) magnets for the Nuclotron Ion-based fAcility (NICA) and Facility for Antiproton and Ion Research (FAIR) projects is currently underway at the Joint Institute for Nuclear Research (JINR) in Dubna, Russia [1]. SC-coil electrical parameters should be checked before each stage of assembling and cryogenic testing to avoid faults, such as inter-turn short circuit and insulation failure. A system for checking of SC-magnets electrical parameters is described in this paper. The results obtained by this system are presented and outlined. [ABSTRACT FROM AUTHOR]

The paper states main provisions of the method for assessing the accumulation of damage in the structure of polymer materials under tensile stresses. The proposed method involves fractal analyses of deformation curves recorded with a high frequency. The minimum coverage method was used to determine the coordinates of critical points identified by the minimum levels of the fractality index. To determine the change in the fractality index depending on the relative elongation, we used a sequence of nested partitions. The amplitude variation was calculated for each of them as a sum of the differences between the maximum and minimum increase in tensile stresses in each analyzed time interval. The fractality index values were determined in the previous time interval of 0.16 sec. with a step of 0.01 sec. The paper provides the results of implementing the proposed method, which makes it possible to determine critical levels of stresses and relative deformations of polymer samples under tensile loads. We used ten samples of epoxy polymer based on modified Etal-247 resin cured by Etal-1472 hardener, including one sample with initial structural defects, as objects of study. We have identified the "critical" levels of tensile stresses and relative elongations, at which the failure rate grows, assessed by the minimum levels of fractality indices of the deformation curves. [ABSTRACT FROM AUTHOR]

Recent testing in a cylindrical, comparative cryostat at the Cryogenics Test Laboratory focused on various seam concepts for multilayer insulation systems. Three main types of seams were investigated: straight overlap, fold-over, and roll wrapped. Each blanket was composed of 40 layer pairs of reflector and spacer materials. The total thickness was approximately 12.5 mm, giving an average layer density of 32 layers per centimeter. Test results show that all three seam concepts are all close in thermal performance; however, the fold-over method provides the lowest heat flux. For the first series of tests, seams were located 120 degrees around the circumference of the cryostat from the previous seam. This technique appears to have lessened the degradation of the blanket due to the seams. In a follow-on test, a 20 layer blanket was tested in a roll wrapped configuration and then cut down the side of the cylinder, taped together, and retested. This test result shows the thermal performance impact of having the seams all in one location versus having the seams clocked around the vessel. This experimental investigation indicates that the method of joining the seams in multilayer insulation systems is not as critical as the quality of the installation process. [ABSTRACT FROM AUTHOR]

A software system implemented on the basis of databases (DBs) is developed for acquisition, storage, and processing of results obtained in experiments performed in blowdown wind tunnels. This system is installed on three aerodynamic facilities of the Khristianovich Institute of Theoretical and Applied Mechanics of the Siberian Branch of the Russian Academy of Sciences and includes experimental data obtained in 1999 – 2020 (more than 5000 experiments). [ABSTRACT FROM AUTHOR]

A novel concept of CH4 decomposition into H2 and carbon materials via a two-step thermochemical and thermo-catalytic conversion process with concentrated solar power is proposed. Solar experiments were conducted in order to investigate the first high-temperature step of the proposed two-step thermochemical conversion process. This step consists of CH4 decomposition into C2-hydrocarbons and hydrogen at high temperatures. A significant effect of H2 addition to CH4 and a beneficial effect of the use of tungsten strips as catalyst on the augmentation of C2H2 and C2H4 yields were observed. [ABSTRACT FROM AUTHOR]

As part of the transnational research project EDITOR, a parabolic trough collector system (PTC) with concrete thermal energy storage (C-TES) was installed and commissioned in Limassol, Cyprus. The system is located on the premises of the beverage manufacturer KEAN Soft Drinks Ltd. and its function is to supply process steam for the factory's pasteurisation process [1]. Depending on the factory's seasonally varying capacity for beverage production, the solar system delivers between 5 and 25 % of the total steam demand. In combination with the C-TES, the solar plant can supply process steam on demand before sunrise or after sunset. Furthermore, the C-TES compensates the PTC during the day in fluctuating weather conditions. The parabolic trough collector as well as the control and oil handling unit is designed and manufactured by Protarget AG, Germany. The C-TES is designed and produced by CADE Soluciones de Ingeniería, S.L., Spain. In the focus of this paper is the description of the operational experience with the PTC, C-TES and boiler during the commissioning and operation phase. Additionally, innovative optimisation measures are presented. [ABSTRACT FROM AUTHOR]

Ultrasonic welding is a widely used joining method for joining individual components. Special features are local heating of the joining partners, short welding times as well as a high economic efficiency of the process. The weld seam quality depends on numerous factors. The welding process is affected intentionally and unintentionally, starting from the process parameters, the tolerances of the welding parts up to theories about a chaotic material behavior. This can lead to varying process qualities. Up to now, the weld seam quality is evaluated only by means of a destructive inspection of the weld seam. The monitoring of the ultrasonic welding process provides information about the weld seam quality within the welding process. Within the scope of this work, the monitoring of the mechanical vibrations occurring in the anvil as well as the temperature development in the joining zone of the weld seam are shown. From characteristic values of the monitoring process, a comparison is made between the weld seam qualities and subsequent tensile tests. The results show a significant correlation between the measured tensile strengths and the energy densities acquired at the piezo oscillator. [ABSTRACT FROM AUTHOR]

Many munitions react violently when subject to Fragment Impact (FI) threats. Previous efforts have identified materials that mitigate / partially mitigate munitions FI response at 6000fps, but have had shortfalls at 8300fps. While existing materials are known to improve / partially mitigate munitions' FI response at 8300fps, the materials / configurations are costly, both logistically and financially. O ne f acet o f s uccessful m itigation t hat h as p roven t o r esult i n l ess v iolent r eactions i s the breakup and dispersion of the steel fragment, resulting in reduced velocity, spreading the imparted kinetic energy into the explosive, thereby reducing the power density. It is conceived that high density and layered protection materials provide the ballistic properties needed to fracture and disperse the fragment projectile. There is a shortfall in empirical data demonstrating this fragment breakup as a result of different protection schemes. This paper will discuss the methodology for the parametric study, data analysis, and results of the breakup and dispersion of an 8300fps standard NATO mild steel fragment (IAW STANAG 4496), after impacting baseline and armor targets at specified thicknesses, based on experimental testing and comparative modeling. [ABSTRACT FROM AUTHOR]

In this research, cogon grass powder and methyl ethyl ketone was used as fillers and catalyst, respectively to improve the mechanical properties of unsaturated polyester resin particle board prepared by compression molding. Cogon grass powder was added with different amount of composition (10, 20, 30 and 40 wt%) and variation of particle size (90/110, 110/130, 130/150 and 150/170 mesh). The addition of cogon grass powder as fillers increased the physical and mechanical properties of particle board as amount of the fillers increased except for the addition of cogon grass up to 40 wt%. The density of the particle board decreased as fillers composition increased, while thickness swelling of the particle board increased as fillers compositions increased. The result of mechanical properties showed that the particle board had modulus of rupture (MOR) 60.039 MPa and modulus of elasticity (MOE) 207.306 MPa. The results of physical and mechanical properties approached that of values in standard JIS A 5908-2003 except for modulus of elasticity. [ABSTRACT FROM AUTHOR]