Nanoindentation creep testing: Advantages and limitations of the constant contact pressure method

Different loading protocols have been developed in the past to investigate the creep properties of materials using instrumented indentation testing technique. Recently, a new indentation creep method was presented, in which the contact pressure is kept constant during the creep test segment, similar to the constant stress applied in a uniaxial creep experiment. In this study, the results of constant contact pressure creep tests are compared to uniaxial and constant load hold indentation creep experiments on ultrafine grained Cu and CuAl5. The constant contact pressure method yields similar stress exponents as the uniaxial tests, down to indentation strain rates of 10–6 s−1, whereas the constant load hold method results mainly in a relaxation of the material at decreasing applied pressures. Furthermore, a pronounced change in the power law exponent at large stress reductions is found for both uniaxial and constant contact pressure tests, indicating a change in deformation mechanism of ultrafine grained metals. Graphical abstract

RESEARCH OF THE POSSIBILITY OF TRANSMISSION OF LIQUEFIED NATURAL GAS THROUGH A PIPELINE BY A NON-PRESSURE METHOD

This article discusses the problems of transmission of liquefied natural gas through a non-pressure pipeline from a stationary storage facility to a transport cryogenic tank and ways to solve them. Theoretical studies have been carried out, including mathematical modeling of thermal and hydrodynamic processes during the transmission of liquefied natural gas through a pipeline by a non-pressure method.

Study on Gas Leakage Detection and Pressure Difference Identification by Asymmetric Differential Pressure Method

As the most common actuator in the pneumatic system, the excellent air tightness of the tank is the key to meet the use requirements of automatic equipment. This paper introduces the common air tightness detection contents, and models the inflation and detection process of the differential pressure method. In order to break away from the restriction on the detection efficiency caused by the asynchronous temperature recovery of the two chambers in the asymmetric differential pressure method, the differential calculation of directly detected pressure difference is replaced by the pressure difference substitute formula. The influence of various parameters in the fitting formula is analyzed by simulation, and the effectiveness of this method is verified by experiments.

Changes in external ischial tuberosity width at varying trunk–thigh angles between sexes using two measurement methods

This study examined the influence of two methods and various trunk–thigh (TT) angles on external ischial tuberosity width (EITW) for 45 men and 45 women. In the experiment, the impress and seat pressure methods were applied at TT angles of 60°, 75°, 90°, and 105°. When the impress method was used, EITW remained highly consistent across the four measured TT angles with differences of 2.8 and 2.1 mm for men and women, respectively. Conversely, in the seated pressure method, EITW increased with TT angle such that differences in EITW across a full TT angle range were 11.5 and 11.7 mm for men and women, respectively. Irrespective of method, differences in EITW between genders measured approximately 12.6–13.7 mm across all TT angles. Correlation analyses revealed that hip circumference was positively related to EITW in all cases, whereas the relationship of hip width and depth with EITW varied by method and gender. Because of inherent differences in EITW between genders, these findings suggest that gender variability should be considered in seat cushion design.

SYNTHESIS, CHARACTERIZATION AND DYEING PERFORMANCE OF MONO AZO DISPERSE DYES BASED ON 2-AMINO 5-(4'-NITRO PHENYL) 1,3,4-THIADIAZOLE MOIETY

In this paper synthesis of some new mono azo disperse dyes based on 2-amino 5-(4'-nitro phenyl) 1,3,4-thiadiazole moiety has been reported. Preparation of mono azo disperse dyes via condensation and nally diazotization of substituted primary amine and condensed with N-(4-(4'-chlorophenyl)thiazol-2-yl)-2-((5-(4'-nitrophenyl)-1,3,4-thiadiazol-2-yl)amino)acetamide (RR) to 1 give a series of mono azo dyes (RR -RR ). All the dyes were characterized by IR, H NMR, UV-Visible and elemental analysis and their dyeing 1 15 performance evaluated using High Temperature High Pressure method (HTHP) at 130°C on polyester fabric. All dyes gave good to excellent fastness properties.

Enhancement of Strength and Resistance to Sulfate Attack in Bio-Coating Material through Negative Pressure Method for Bacteria Immobilization

In recent years, many studies have been performed on the crack repairing technique in concrete or the protection of the concrete surface against sulfate ions. Bacterial immobilization and survival rate are the dominant influencing factors for the repair of concrete. In this study, a negative pressure method (NPM) was developed to forcibly remove air in the porous materials of concrete, which was applied for surface repair through bio-coating using Rhodobacter capsualtus. For normal repair—repair using the conventional simple soaking method (SSM) and repair through NPM—various evaluations of the concrete strength and durability were performed. Since a reinforced concrete (RC) structure for the application of these repair methods is a sewer pipe exposed to sulfate ingress, variations in concrete mass and strength were analyzed by the accelerated sulfate resistance test. The diffusion coefficient of the sulfate ion in the repair materials and the bacterial count after the accelerating test were also measured. In order to investigate the changes in the properties of the concrete hydrates, surface analyses with SEM, XRD, and TGA were carried out on the concrete under the repair layer after the tests. In all the experimental results, the bacterial immobilization rate was evaluated, and the high immobilization rate indicates the excellent shielding of sulfate ions as well as improves the survival rate of bacteria. This not only improves the service life of the coating repair but also extends the service life of the structure itself. As a result of analyzing the composition of concrete protected by different types of repair, the results most similar to the general concrete composition without sulfate attack were obtained in the case of applying NPM, which shows the least damage from sulfate attack.

First Steps: Synthetic Ammonia in the United States

The synthetic ammonia industry, originally based on Fritz Haber's 1909 invention of a catalytic high-pressure method as scaled up by Carl Bosch at BASF, grew globally in the years following World War I, based on the processes of Brunner, Mond & Co. (Britain), Luigi Casale (Italy), Georges Claude (France), and Giacomo Fauser (Italy). The ammonia was mainly converted into ammonium sulphate fertilizer. There was less impetus in the United States for taking up these developments, because America relied on ammonium sulphate from its by-product coke ovens, sodium nitrate (Chilean nitrate) from South America, ammonia from coal gas works, and calcium cyanamide as manufactured by the American Cyanamid Company. Even when a synthetic ammonia industry started up in the United States, it was on a smaller scale than in Europe. However there emerged just before the Wall Street Crash two major producers of synthetic ammonia, Allied Chemical and Du Pont. This article presents a historical reconstruction of the early synthetic ammonia industry in the United States focusing on the 1920s, paying particular attention to Du Pont's success, which relied on the ammonia process of Casale. Standard accounts suggest that Du Pont acquired Casale technology as the result of a straightforward business acquisition. However, the situation, as shown here, was far more complex. Du Pont had to engage in aggresive litigation in order to acquire rights to the Casale process in 1927.