Indirect Test Method Research Articles

Investigation of the Use of Leeb Hardness in the Estimation of Some Physical and Mechanical Properties of Rock Materials

Uniaxial compressive strength (UCS) and some physical properties of rock materials are very important input parameters used in rock mechanics and engineering. Samples with standard shape and dimension are used in physical and mechanical tests. However, it is difficult to determine the UCS values in case of difficult sample preparation conditions. To overcome this limitation prediction of UCS values from indirect test methods is preferred. One of the most common parameters used to predict the UCS values of rock materials is surface hardness. In this study, the usability of hardness values (HL) of selected ignimbrite, travertine and syenite rocks in the prediction of some physical and mechanical properties were investigated by using the Leeb hardness test which has much lower impact energy than the Schmidt hardness hammer has. Firstly, petrographic and some physical and mechanical properties of the samples were determined and then the HL measurements of all samples were taken. Test results were correlated and correlation equations for dry (dry) and saturated (sat) unit weights, apparent porosity (nA), water absorption (wS), sonic wave velocity (VP) were presented and prediction equation of UCS from HL measurements were proposed. In the context of the study, the effect of L/D ratio on HL measurements were also investigated and minimum length to diameter (L/D) ratio of 1.5 on samples with 50 mm in diameter was suggested for consistent HL measurements.

Identification of Novel Microsatellite Markers Flanking the SMN1 and SMN2 Duplicated Region and Inclusion Into a Single-Tube Tridecaplex Panel for Haplotype-Based Preimplantation Genetic Testing of Spinal Muscular Atrophy.

Preimplantation genetic testing for the monogenic disorder (PGT-M) spinal muscular atrophy (SMA) is significantly improved by supplementation of SMN1 deletion detection with marker-based linkage analysis. To expand the availability of informative markers for PGT-M of SMA, we identified novel non-duplicated and highly polymorphic microsatellite markers closely flanking the SMN1 and SMN2 duplicated region. Six of the novel markers within 0.5 Mb of the 1.7 Mb duplicated region containing SMN1 and SMN2 (SMA6863, SMA6873, SMA6877, SMA7093, SMA7115, and SMA7120) and seven established markers (D5S1417, D5S1413, D5S1370, D5S1408, D5S610, D5S1999, and D5S637), all with predicted high heterozygosity values, were selected and optimized in a tridecaplex PCR panel, and their polymorphism indices were determined in two populations. Observed marker heterozygosities in the Chinese and Caucasian populations ranged from 0.54 to 0.86, and 98.4% of genotyped individuals (185 of 188) were heterozygous for ≥2 markers on either side of SMN1. The marker panel was evaluated for disease haplotype phasing using single cells from two parent–child trios after whole-genome amplification, and applied to a clinical IVF (in vitro fertilization) PGT-M cycle in an at-risk couple, in parallel with SMN1 deletion detection. Both direct and indirect test methods determined that none of five tested embryos were at risk for SMA, with haplotype analysis further identifying one embryo as unaffected and four as carriers. Fresh transfer of the unaffected embryo did not lead to implantation, but subsequent frozen-thaw transfer of a carrier embryo produced a pregnancy, with fetal genotype confirmed by amniocentesis, and a live birth at term.

Determination of Modulus of Dynamic Elasticity of Wood Using Ultrasonic Pulse Velocity Testing

In the present times, Non Destructive Tests have been applied in many quality evaluations of existing wood structures. One of the Non Destructive Tests (NDT) is based on Ultrasonic Pulse Velocity (UPV). The use of UPV method among others are to estimate the strength of wood, the grade of wood based on Specific Gravity as well as elastic properties of wood. This research will apply the NDT technique. This research used 15 wood test samples in five groups, which were reference Teak (code JT), Yellow Ballau (BK), Camphor (KP), Coconut (KL), and Breadfruit (SK). Those samples were of 100 mm in width, 60 mm in depth, and 500 mm in length. The Ultrasonic Pulse Velocity(UPV) test was conducted with indirect test method. The test result showed that the objects test of Teak, Yellow Ballau, Camphor, Coconut, and Breadfruit are 5,65 km/s, 6,34 km/s, 6,12 km/s, 4, 72 km/s, and 4,94 km/s. Result also showed that Dynamic Modulus of Elasticity (MOEd) for the objects test are 144683 kg/cm2, 314101 kg/cm2, 173973 kg/cm2, 160094,64 kg/cm2, dan 73157,74 kg/cm2.

Dynamic error testing method of electricity meters by a pseudo random distorted test signal

The complex random characteristics of dynamic loads in smart grid lead to the metering errors exceed the limits of electricity meters used in real field, these errors are called dynamic errors. By analyzing the typical intrinsic characteristics of large power dynamic loads and the nonadaptive linear modulation of compressive sensing (CS), this paper firstly constructs an orthogonal pseudo random measurement (OPRM) matrix to modulate distorted steady-state test signal (DSTS) and then proposes an orthogonal pseudo random measurement distorted dynamic test signal (OPRM-DDTS) with the intrinsic characteristics. In addition, an indirect likelihood function testing method is also proposed to solve the problems of both electricity meter dynamic error testing and dynamic reference electrical energy traceability. At last, a dynamic error testing system is built for verifying the indirect testing method under orthogonal pseudo random distorted dynamic test signal conditions, the dynamic errors of different electricity meters are given. Experimental results show that the orthogonal pseudo random distorted dynamic test signal and the indirect likelihood function testing method are effective for dynamic error testing of electricity meters, meanwhile, the measurement uncertainty of the dynamic error testing system is better than 0.042% (coverage factor k = 2).

Influence of cooling rate and additives on low-temperature properties of asphalt mixtures in the TSRST

The paper presents the results and analysis of low-temperature properties of asphalt mixtures according to Thermal Stress Restrained Specimen Test (TSRST) and Indirect Tensile Test methods. Different groups of bitumen were investigated: neat, SBS-modified and highly SBS-modified. Influence of cooling rates (1 °C/h, 3 °C/h, 5 °C/h and 10 °C/h) and additives (aramid fibres and crumb rubber) was identified as well. Moreover, for each factor stiffness moduli were back-calculated from the TSRST results and analysed. The greatest impact on the TSRST results had type of bitumen, followed by the cooling rate and additives. Application of longer fibres improved low-temperature properties of the asphalt mixtures.

Indirect density tests for thin asphalt overlay – part 1: review

Quality in construction of asphalt pavements plays a significant role in long-term durability. In situ density is a key parameter in construction quality and there are several available test methods. However, there are questions as to whether a particular test provides density values (referred to as ‘quality assurance’) or density changes (referred to as ‘quality control’). This paper presents findings from a literature review of indirect density testing on asphalt pavements. A specific interest is on thin overlays in the 30–50 mm thickness range typically used in the UK. Indirect test methods include nuclear density gauge, electromagnetic instruments, ground-penetrating radar and step frequency radar. The advantages and limitations of these methods for thin asphalt in situ density measurement are discussed in this paper.

Donath-Landsteiner test

The Donath-Landsteiner (DL) test is a serologic test used to detect the presence of a biphasic hemolysin. This autoantibody is seen in patients with paroxysmal cold hemoglobinuria. The test relies on the characteristic cold binding of an IgG autoantibody with specificity to the P blood group antigen. This autoantibody causes complement-mediated red blood cell (RBC) lysis when warmed to body temperature. In this review, we describe the various methods for performing the DL test-namely a direct test, an indirect test, an indirect test with modifications such as the use of enzyme-treated RBCs and two stages, and an indirect antiglobulin DL test-and highlight the advantages and disadvantages of each. Our focus is on the indirect testing method as it is most commonly used in blood bank laboratories.

Bearing capacity of steel thin-walled profiles in reliability assessment

The increasing use of light steel thin-walled structures is determined by the efficiency of the production of cold-formed profiles. However, there are problems of calculating the reliability of thin-walled structures. In particular, it is necessary to specify the calculation of the generalized bearing capacity of an element from a thin-walled profile. Such an element is significantly affected by the initial geometric imperfections reducing its bearing capacity. At the same time the element is influenced by an uneven distribution of the mechanical characteristics of the steel over the section of the profile. A thin-walled element of paired sigma profiles with a section height of 300 mm was taken as the object of study. This paper presents the results of the calculation of the effective characteristics of a thin-walled profile operating under axial compression with bending without and with the initial geometric imperfections (additional eccentricity from the element’s initial curvatures). Besides, the paper reveals the results of laboratory studies of the distribution of the mechanical properties of steel over the cross section of a thin-walled profile after using direct and indirect test methods.

PERSENTASE VARIASI FENOTIP ANTIGEN ABO DAN ANTIGEN DUFFY PADA MAHASISWA AKADEMI BAKTI KEMANUSIAAN PALANG MERAH INDONESIA ANGKATAN SATU

Every person has a blood type system and different types of antigens on the surface of red blood cells. Before the blood is transfused into the patient's body, a pre-transfusion examination must be performed and a transfusion reaction is detected which is marked by antibodies to red blood cells. To prevent transfusion reactions by administering appropriate and safe blood. One of them is by checking ABO blood group first. Then another blood type examination can be performed which can also cause a transfusion reaction, but this has not been possible because of the limitations of routine pre-transfusion examinations performed for patients who do not have specific antibodies with donor antigens. To find out the percentage variation of ABO antigen and Duffy antigen phenotypes at the Indonesian Red Cross Human Rights Academy Students Force One. Analytical Observation. Sample of the Indonesian Red Cross Indonesian Human Services Academy Student Force One. Forty samples of the 1st batch of ABK PMI students with unknown ABO antigen type and Fya or Fyb antigen type were tested for phenotyping using Direct Coomb’s Test and Indirect Coomb's Test (ICT) methods. From the results of the phenotyping examination, the results showed that blood group A was 11 samples (27%), blood group B 12 samples (30%), blood group AB 2 samples (5%), blood group O 15 samples (38%) and Fya 37 samples ( 92%) and Fyb 3 (8%) of 40 samples (100%). It can be concluded that the majority have blood type O blood and have Fya antigens on the sample of ABK PMI student class one. Phenotyping is expected to reduce the risk of transfusion reactions by providing donor blood that has an antigen that is not specific to the antibodies that the patient has so that the transfusion reaction does not occur.

Effect of Sample Dimension on Three and Four Points Bending Tests of Fine Crystalline Marble and its Relationship with Direct Tensile Strength

The indirect tensile strength test methods such as three and four points bending tests and Brazilian tests have been commonly used tensile strength determination and other mechanical properties of rocks since it is a quick, easy, and inexpensive testing methods. EN and ASTM standards suggested that sample dimensions of three and four points bending tests have been different from each other. The aim of this study, in order to analyses the effect of sample dimension on bending strength property of fine crystalline marble and is to determine the direct tensile strength (DTS) of rock by using new dumbbell shape. Indirect tensile strength of marble was determined by using three and four-point bending test methods according to related standards. In addition to experimental study, stress distribution and stress intensity on the sample was analyzed by using ANSYS. As a result, four-point bending test is more suitable for determining of tensile strength of marble.

Determination of the Direct Tensile Strength of Granite Rock by Using a New Dumbbell Shape and its Relationship with Brazilian Tensile Strength

In this study, the determination of the direct and indirect tensile strength of granite rock was carried out in compliance with related standard test methods. In order to analyze rock tensile strength between direct (with using a new dumbbell shape) and indirect (Brazilian tensile strength) test methods were conducted and obtained results were compared between them. A new dumbbell shape samples were used in direct tensile tests and cylindrical specimens, which have different t/D ratios such as 0.5, 0.75, and 1.0, were used in Brazilian tests. Moreover, stress distribution and the stress intensity within the sample were analyzed with Finite Elements Method (FEM) and numerical modeling techniques by using ANSYS R18 software. The direct tensile test yielded lower strength values than the indirect test. For the specimens tested in direct tensile test, failure occurred middle of the dumbbell shape sample due to lower stress intensity factor. Since Brazilian disc test, stress value in the diametrical line of the specimen has been found higher than nominal stress value according to FEM, tensile strength value that should be re-calculated by using any coefficient. Moreover, t / D ratio did not affect the Brazilian test results.

Antimicrobial characteristics and biocompatibility of the surgical sutures coated with biosynthesized silver nanoparticles

Surgical sutures play important role during the wound healing of the surgical sites which are known to be sensitive to microbial infections. Silver nanoparticles (AgNPs) have been recently used as promising agents against multiple-drug resistant microorganisms. This study was designed to coat the sutures with silver nanoparticles obtained via a green synthesis approach. Microbial-mediated biological synthesis of AgNPs were carried out ecofriendly using Streptomyces sp. AU2 cell-free extract and deposited on silk sutures through an in situ process. Sutures coated with biosyntehsized AgNP (bio-AgNP coated sutures) were characterized using Scanning Electron Microscopy (SEM) and elemantal analysis were carried out using Energy Dispersive X-ray Spectroscopy (EDS). The silver amount released by the bio-AgNP coated sutures was calculated by Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) throughout a degradation process. Antimicrobial potential of the bio-AgNP coated sutures was determined against common pathogenic microorganisms Candida albicans, Escherichia coli and Staphylococcus aureus. To determine the biocompatibility/cytotoxicty of the bio-AgNP coated sutures, the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium) assay was used through an indirect test method; that the elutions obtained by the extraction of the sutures at 1, 4, 8 and 10. days and were placed in contact with 3T3 fibroblast cell culture. To best of our knowledge, this is the first report about coating of the nonabsorbable silk sutures with silver nanoparticles biosynthesized using a microbial extract.

Analysis and Discussion of the Indirect Testing Method for the Losses of Permanent Magnet Synchronous Machines

The losses of permanent magnet synchronous machine (PMSM) are always cared in the machine system, since the losses mainly determine the temperature-rise and efficiency of the machine. An indirect-testing method for the losses of PMSM has been proposed in order to measure the losses without any mechanical load in the test. The aims of this paper are to analyze the influence factors on this method and discuss the application of this method. The influences of the pole–slot combination, saturation, harmonic content, and frequency on the test error are analyzed. To validate the analysis, the indirect-testing losses and the direct-testing losses are compared with the test of a PMSM prototype.

Financial stability: To regulate or not? A public choice inquiry

The paper takes the stand that the central banks as financial regulators have their own interest in imposing more regulations. It models the institutional behaviour for the central bank and government using the Indirect Inference testing and estimation method and it finds a set of coefficients of the model that can generate the actual observed behaviour for the US. The paper establishes that good monetary policy can reduce instability. Regulation at worse destabilises the economy and at best contributes little to stabilise the economy. After the financial crisis, financial regulations were too severe and thus actually increased instability.

Adaptive inverse analysis (AIA) applied and verified on various fiber reinforced concrete composites

During the past decades several inverse approaches have been developed to identify the stress-crack opening ( $${\sigma }-w$$ ) by means of indirect test methods, such as the notched three point bending-, wedge splitting-, and round panel testing. The aim is to establish reliable constitutive models for the tensile behavior of fiber reinforced concrete materials, suitable for structural design. Within this context, the adaptive inverse analysis (AIA) was recently developed to facilitate a fully general and automatized inverse analysis scheme, which is applicable in conjunction with analytical or finite element simulation of the experimental response. This paper presents a new formulation of the adaptive refinement criterion of the AIA method. The paper demonstrates that the refinement criterion of the nonlinear least square curve fitting process, is significantly improved by coupling the model error to the crack mouth opening and the crack opening displacement relationship ( $$w_{\mathrm{cmod}}-w_{\mathrm{cod}}$$ ). This enables an adaptive refinement of the $${\sigma }-w$$ model in the line segment with maximum model error, which entails significant improvement of the numerical efficiency of the AIA method without any loss of robustness. The improved method is applied on various fiber reinforced concrete composites and the results are benchmarked with the inverse analysis method suggested by the Japanese Concrete Institute (Method of test for fracture energy of concrete by use of notched beam, Japanese Concrete Institute Standard, Tokyo, 2003) and recently adopted in ISO 19044 (Test methods for fibre-reinforced cementitious composites—load-displacement curve using notched specimen, 2015). The benchmarking demonstrates that the AIA method, in contradiction to the JCI/ISO method, facilitates direct determination of the tensile strength and operational multi-linear $${\sigma }-w$$ models.

Analysis of mechanical and chemical mechanisms on cavitation erosion-corrosion of steels in salt water using electrochemical methods

Abstract Cavitation erosion-corrosion causes damage and removal of material especially in rotors of centrifugal pumps, water turbines, as well as in control valves and in motors. Based on a dynamic corrosion model the pure mechanical erosion amount of different steel alloys was identified using an indirect cavitation test method combined with an electrochemical cell. We demonstrate that cavitation erosion can be enormously reduced by application of external cathodic potentials. The cavitation rate was in-situ determined using atomic emission spectrometry during the cavitation test. Due to the separately identified pure mechanical and the combined corrosive and synergistic cavitation erosion-corrosion correlation with hardness and arising charge densities during cathodic potentials were found for the mechanical part.

Energy Absorption of Pultruded Glass-Graphite/Epoxy Hybrid Composites under High Strain-Rate Induced Transverse Tension

This paper focuses on the dynamic tensile response of glass-graphite/epoxy composites illustrating improvement in energy absorption through hybridization. The dynamic response and energy absorption characteristics of pultruded hybrid combinations of glass and graphite fibers in an epoxy matrix subjected to induced transverse tension at high strain-rate in a modified Split Hopkinson Pressure Bar (SHPB) apparatus, are presented. Transverse tensile strength was determined by diametral compression of disc samples (Brazilian indirect tensile test method). Diametral crack initiation and strain to failure were monitored with a Shimadzu HPV-2 high-speed video camera at a recording speed of 500,000 fps and Digital Image Correlation (DIC). Adequate measures were taken to ensure that initiation of specimen failure occurred at the exact center of the disc specimen, and propagated through the diameter along the compressive loading axis, for the induced transverse tension tests to be valid. A study of the strength and specific energy absorption demonstrates the benefits of hybridization. Under induced transverse tensile loading condition, the pure glass/epoxy (GL60) exhibited higher strength than pure graphite/epoxy (GR60). Pure graphite/epoxy (GR60) has higher specific energy absorption capacity than pure glass/epoxy (GL60) in transverse tension. Among all hybrids, GR30 has the highest specific energy absorption under transverse tension. Overall, hybrid GL48, with 48% low-cost glass fibers in the inner core and 12% high-cost graphite fibers in outer shell, was found to exhibit better performance under induced transverse tension at high strain-rates, showing the benefits of hybridization.

Indirect test methods for the mechanical characterization of building stones

The main objective of this study is to evaluate the usefulness of indirect methods to estimate the uniaxial compressive strength (UCS) of building stones. For this purpose, the results of the UCS test on five types of stones from southern Italy, one igneous and four sedimentary stones are firstly correlated with the corresponding results from Schmidt hammer, point load and UCS direct tests. Then, derived correlations are compared with the equations obtained by different researchers in the mechanical stone characterization.

ANTINUCLEAR ANTIBODIES IN PATIENTS WITH UNEXPLAINED RECURRENT ABORTIONS

Objective:This study aims to determine the prevalence of antinuclear antibodies in pregnant women with bad obstetric history (BOH) against healthy multigravid women in and around Tirunelveli districtMethods: This is a case-control study comprising 60 antenatal women with BOH against 60 multiparous pregnant women with no history of abortions. Antinuclear antibodies (ANA) were detected using indirect immunofluorescence with Hep-2 cell substrate, and enzyme-linked immunosorbent assay (ELISA).Results: Among BOH cases 19 (82.6%), 18 (78.26%) were positive by ELISA and indirect fluorescence antibody test (IFAT) method, respectively. Among controls, 4(17.39%) and 5(21.73%) individuals were positive by ELISA and IFAT methods, respectively. Of the 18 positives, homogenous pattern was most common followed by anticentromere pattern, fine speckled and coarse speckled patternConclusion: IFAT is considered to be gold standard in the diagnosis of autoimmune disorders, but ELISA appears to be a suitable simple alternative for testing rheumatological disorders.

Numerical Simulation of Creep Characteristic for Composite Rock Mass with Weak Interlayer

The composite rock mass with weak interlayer is widely exist in engineering, and it’s essential to research the creep behavior which could cause stability problems of rock engineering and production accidents. However, due to it is difficult to take samples, the losses and damages in delivery and machining process, we always cannot get enough natural layered composite rock mass samples, so the indirect test method has been widely used. In this paper, we used ANSYS software (a General Finite Element software produced by American ANSYS, Inc) to carry out the numerical simulation based on the uniaxial compression creep experiments of artificial composite rock mass with weak interlayer, after experimental data fitted. The results show that the laws obtained by numerical simulations and experiments are consistent. Thus confirmed that carry out numerical simulation for the creep characteristics of rock mass with ANSYS software is feasible, and this method can also be extended to other underground engineering of simulate the weak intercalations.