Various Types Of Specimens Research Articles

Model-based system design of annealing simulators

We discuss several aspects of mechatronic product development processes, such as finding and evaluating design concepts and dependencies between design parameters. One of the key issues in the development of modern mechatronic systems is the benefit of consistent integration of mechanical, electrical, and electronic control and software aspects from the very beginning of the earliest design phases. Even for a single design problem defined by a given specification, different designers will probably respond with a variety of different design concepts, each of which may be acceptable in terms of meeting the specification. In the conceptual design phase, we propose that some aspects of design, such as hierarchy of parameters and modularity of the design, are analysed with conceptual models. The application presented in this paper shows the conceptual design of an experimental laboratory annealing simulator (anneal.sim-lab). Physical simulation of the annealing process requires consideration of different heating methods for various types of specimen. One critical step is the modularisation of sections (annealing, cooling, and quenching), and their geometric arrangement. We use a design structure matrix to analyse the requirements and their structure and demonstrate a realisation in a parametric 3D-CAD model.

Special features of calculation of C* -integral in thermomechanical loading of structural elements

The results of the C* -integral calculation, which is used for mechanical loading cases, are compared to finite eelement calculation results for various types of specimens. A design analysis of the crack-tip stress state has been carried out for force and kinematic boundary conditions in creep and stress relaxation. The C* -integral has been calculated for the same conditions. Based on the present investigations, an engineering method is put forward which permits calculating the C* -integral for both force and kinematic boundary conditions as well as for thermomechanical loading.

Numerical Analysis of Sample-Size Effect on Strength of Alumina

Statistical characteristics of strength distribution in ceramic components should be clarified because of large scatter in ceramics strength. Characteristics of strength distribution, however, depend on sample size, i.e., the number of tested specimens. In this study, a numerical procedure in the framework of fracture mechanics was developed to estimate strength distribution of ceramics by assuming the same statistical distribution of cracks in a material. Experimental results in four-point bending tests of alumina, which were reported in a previous work, were cited to verify the validity of the developed procedure. Smooth specimens of distinct sizes as well as notched specimens with different notch shapes were used in the experiment. Monte Carlo simulations using the developed procedure were carried out to investigate effects of the sample size on strength properties of alumina specimens with various shapes. The simulated result revealed that the experimental strength for various types of specimens was almost covered within a range of upper and lower bounds of strength simulated for the alumina. The experimental mean strength correlated with the effective volume was also included in a band range between the maximum and the minimum of mean strength obtained by the simulation.

The Compaoparison of Characteristics of Fracture Toughness of Materials for Nuclear Piping by Use of Various Types of Specimens

Since it is difficult to cut off large specimens from nuclear piping, generally the standard CT specimens of 1T are used to perform fracture toughness tests. However, when compared with the test result obtained from a real pipe, the results from CT specimens are been known to be very conservative. Therefore, the U.S. Nuclear Regulatory Commission recommends the use of specimens whose thickness is greater than or equal to the thickness of a real pipe for estimating the stability of crack resistance[1]. In this study, a series of fracture toughness tests were performed using various types of specimens: the standard CT, non-standard Compact Pipe, and Curved CT. The results of the tests were compared.

Evaluation of fracture toughness characteristics for nuclear piping using various types of specimens

The leak-before-break (LBB) concept is based on the fracture resistance curve obtained by J-R tests for various types of specimens. But fracture toughness data of various types of specimens are different. For example, the estimates for fracture toughness of standard specimens are conservative when compared to the fracture toughness of real pipes because of the difference of the constraint effect between real pipes and standard specimens. Therefore, to estimate the integrity of real pipes based on elastic–plastic fracture mechanics, we have to first establish the relations among real pipes, standard CT specimens and curved CT specimens. In this study, we perform fracture toughness tests of nuclear piping materials using various types of specimens. And each J-R curve considered in the constraint effect is compared. The experimental results showed that a curved CT specimen is similar to the cases of pipes with small crack angles (60° and 120°) and a CT specimen is similar to the case of pipes with the crack length of 180°. Also, the Q-stress for curved CT specimens is higher than that of pure bending pipe specimens and lower than that of CT specimens.

Analysis of applicability of small-sized specimens to prediction of temperature dependence of fracture toughness

The paper addresses the use of small-sized specimens of various types, including those with deep (50%) side grooves, for the purpose of fracture toughness prediction. The experimental data for numerous (more than 500) small-sized specimens prepared from materials of various degrees of embrittlement are compared to the test results for full-sized specimens of C(T) type. The concepts of Master Curve and Unified Curve are applied for the processing of experimental data. To handle the test results for small-sized deep-grooved specimens a calculation procedure has been elaborated, which adjusts the calculation method specified in the ASTM Standard E 1921. We provide recommendations of how to use precracked Charpy type deep-grooved (50%) specimens for prediction of a representative temperature dependence of fracture toughness.

Standard Operating Procedures for Serum and Plasma Collection: Early Detection Research Network Consensus Statement Standard Operating Procedure Integration Working Group

Specimen collection is an integral component of clinical research. Specimens from subjects with various stages of cancers or other conditions, as well as those without disease, are critical tools in the hunt for biomarkers, predictors, or tests that will detect serious diseases earlier or more readily than currently possible. Analytic methodologies evolve quickly. Access to high-quality specimens, collected and handled in standardized ways that minimize potential bias or confounding factors, is key to the "bench to bedside" aim of translational research. It is essential that standard operating procedures, "the how" of creating the repositories, be defined prospectively when designing clinical trials. Small differences in the processing or handling of a specimen can have dramatic effects in analytical reliability and reproducibility, especially when multiplex methods are used. A representative working group, Standard Operating Procedures Internal Working Group (SOPIWG), comprised of members from across Early Detection Research Network (EDRN) was formed to develop standard operating procedures (SOPs) for various types of specimens collected and managed for our biomarker discovery and validation work. This report presents our consensus on SOPs for the collection, processing, handling, and storage of serum and plasma for biomarker discovery and validation.

Closed-Form Stress Intensity Factor Solutions for Spot Welds in Various Types of Specimens

Closed-Form Stress Intensity Factor Solutions for Spot Welds in Various Types of Specimens

Closed-form structural stress and stress intensity factor solutions for spot welds under various types of loading conditions

The theoretical framework and closed-form stress intensity factor solutions in terms of the structural stresses for spot welds under various types of loading conditions are presented based on elasticity theories and fracture mechanics. A mechanics description of loading conditions for a finite plate with a rigid inclusion is first presented. The loading conditions of interest are the resultant loads on the inclusion with respect to the center of the inclusion in a finite or infinite plate and the surface tractions on the lateral surface of a finite or infinite plate. The surface tractions on the lateral surface of the plate can be decomposed into a load-balanced part and a self-balanced part. The load-balanced part is statically in equilibrium with the resultant loads acting on the inclusion. The self-balanced part can be represented by the resultant loads on the lateral surface of the plate. The resultant loads on the inclusion and the self-balanced resultant loads on the lateral surface are then decomposed into various types of symmetric and anti-symmetric parts. Based on the stress function approach and the Kirchhoff plate theory for linear elastic materials, closed-form in-plane stress, moment and transverse shear force solutions are derived for a plate with a rigid inclusion subjected to various types of resultant loads on the inclusion and various types of resultant loads on the plate lateral surface. Based on the J integral for a strip model, closed-form analytical stress intensity factor solutions for spot welds joining two sheets of equal thickness are derived in terms of the structural stresses around a rigid inclusion in a plate under various types of loading conditions. The closed-form solutions presented in this paper are used as the basis to develop new analytical stress intensity factor solutions for spot welds in various types of specimens presented in a subsequent paper.

Fatigue Life Evaluation of Pipe Welds in Power Plant Using Advanced Nondestructive Methods

The objective of this study is to estimate the feasibility of advanced nondestructive method(X-ray diffraction, AE(acoustic emission) and BN(barkhausen noise)measurement application for fatigue life evaluation of the high-temperature pipeline steel such as main steam pipe etc. in power plant. In this study, various nondestructive tests using various types of specimen simulated low cycle fatigue damage were performed in order to analyze fatigue properties when fatigue damage conditions become various stages such as 1/4, 1/2 and 3/4 of fatigue life, respectively. As a result of X-ray diffraction tests for specimens simulated fatigue damages, we conformed that the variation of the full width at half maximum intensity decreased in proportion to the increase of fatigue life ratio. And also, AE and BN signal due to fatigue damage has linear relationship with fatigue life ratio algebraically. From this relationship, it was suggested that direct expectation of the life consumption rate was feasible.

Three-Dimensional Electromechanical Impedance Model. II: Damage Analysis and PZT Characterization

Piezoceramic transducers (PZTs) are extensively used in the nondestructive evaluation of damages in various engineering structures. This paper, the second of a two-part paper, focuses on the application of a PZT using three-dimensional (3D) directional sum impedance (DSI). The semianalytical 3D admittance has been formulated and experimentally validated in the first paper. This part deals with the application of the 3D DSI model in damage analysis where by damages were numerically simulated for various types of specimens and the DSI admittance signatures were predicted and compared. The deviations of the signature from that of the undamaged state provide an indicator for the health of the structure. This technique is nondestructive in nature, and the damages were quantified using root-mean-square deviation in signatures with respect to the undamaged state signature. In Part I, the properties of the PZT and their influences on admittance signatures were briefly presented. In this part, a thorough investigation was made and the importance of all the PZT properties in damage analysis was presented.

Choosing the place for cutting specimens for impact bending tests of reinforcing steel

Results of impact bending tests of specimens of various types and cutting variants are presented. The type of specimen for impact bending testing of hot-rolled reinforcing steel, the place for its cutting from the reinforcement, and the location of the notch are suggested. The expediency of the choice is substantiated. The possibility of the use in Mongolian standards of recommendations accepted in international practice for other steels is considered.

An experimental technique for the strain measurement of small structures using pattern recognition

For an accurate measurement of the material behavior of small structures, an optical experimental technique is proposed. The test method uses a dual field of view microscope and the pattern matching algorithm. The dual field of view microscope can separately magnify the images of two adjacent regions to enhance the measurement resolution. The magnified views of the dual field of view microscope are captured by CCD cameras and the relative deformation is measured by tracing patterns in the images. A pattern matching and tracing algorithm was adapted to measure the movement of region of interests (ROI) in real time. Using the movement information of the patterns, the strain of a specimen can be obtained. This technique is non-contact as well as easy to apply to a specimen. It can be also applied in various types of specimens without any specimen preparation. Using this experimental technique, the deformation of solder joints in electronic packaging and the strain of the nickel thin film are successfully measured.

Methicillin (Oxacillin)-resistant Staphylococcus aureus strains isolated from major food animals and their potential transmission to humans.

From May 2001 to April 2003, various types of specimens from cattle, pigs, and chickens were collected and examined for the presence of methicillin (oxacillin)-resistant Staphylococcus aureus (MRSA). S. aureus was isolated and positively identified by using Gram staining, colony morphology, tests for coagulase and urease activities, and an API Staph Ident system. Among 1,913 specimens collected from the animals, 421 contained S. aureus; of these, 28 contained S. aureus resistant to concentrations of oxacillin higher than 2 micro g/ml. Isolates from 15 of the 28 specimens were positive by PCR for the mecA gene. Of the 15 mecA-positive MRSA isolates, 12 were from dairy cows and 3 were from chickens. Antimicrobial susceptibility tests of mecA-positive MRSA strains were performed by the disk diffusion method. All isolates were resistant to members of the penicillin family, such as ampicillin, oxacillin, and penicillin. All isolates were also susceptible to amikacin, vancomycin, and trimethoprim-sulfamethoxazole. To determine molecular epidemiological relatedness of these 15 animal MRSA isolates to isolates from humans, random amplified polymorphic DNA (RAPD) patterns were generated by arbitrarily primed PCR. The RAPD patterns of six of the isolates from animals were identical to the patterns of certain isolates from humans. The antibiotypes of the six animal isolates revealed types similar to those of the human isolates. These data suggested that the genomes of the six animal MRSA isolates were very closely related to those of some human MRSA isolates and were a possible source of human infections caused by consuming contaminated food products made from these animals.

A novel simple one-step single-tube RT-duplex PCR method with an internal control for detection of bovine viral diarrhoea virus in bulk milk, blood, and follicular fluid samples

A simple one-step single-tube RT-PCR method was developed for detection of bovine viral diarrhea virus (BVDV) in bulk milk, blood and follicular fluid samples. A set of universal primers (UTR DL1/4) was designed for RT-PCR to detect BVDV type I and II viruses simultaneously and was tested for efficacy in comparison to published primers for two type strains, 42 field isolates, and 95 diagnostic samples. The sensitivity (100%) and specificity (96.2%) of the RT-PCR assay, with the universal primers for 95 diagnostic samples, were equal to those of virus isolation. An internal control targeting a bovine actin gene was also included in the same reaction tube to monitor RNA preparation and RT-PCR procedure. A total of 632 specimens (378 bulk milk, 140 blood, and 112 follicular samples) were tested in the year 2000 by the RT-duplex PCR assay in parallel with virus isolation. The one-step single-tube RT-duplex PCR with the universal primers UTR DL1/4 was sensitive, specific, less complicated and cost effective for detection of BVDV in various types of specimens.

Adhesion of aspirated tumor cells to extracellular matrix proteins: a new methodology utilizing fine-needle aspiration.

Cell adhesion molecules mediate the interactions of cells with other cells and with extracellular matrix components. Such interactions may be important in the development of tumor invasion and metastasis. This article describes a new approach to the evaluation of tumor cell-matrix interactions by utilizing fine-needle aspiration of resected tumors. Fine-needle aspiration was performed on 15 fresh surgical specimens of various types of carcinomas. After partial purification by isotonic Percoll centrifugation, tumor cell adhesion to collagen Type IV, laminin, and fibronectin was evaluated by counting cytologically malignant cells adhering to matrix-coated plastic substrates. Frozen tissue sections of the corresponding tumors were studied simultaneously for immunohistochemical expression of alpha-2, alpha-3, alpha-4, and alpha-5 integrin subunit expression. Results of the immunohistochemical staining then were compared with the adhesion data for particular tumors. In general, the majority of the tumors exhibited little or no adhesion to collagen or laminin, but several tumors showed marked adhesion to fibronectin. Striking differences were noted between some tumors of the same histologic subtype. Competitive inhibition studies performed with two of the tumors (a large cell carcinoma and a renal cell carcinoma) showed decreased adhesion to fibronectin in the presence of anti-alpha-5, suggesting at least a partial role for the alpha-5-beta 1 fibronectin receptor in mediating the adhesion of these tumors to fibronectin. All the tumors examined exhibited strong immunohistochemical expression of the alpha-2 and alpha-3 integrin subunits, and all were negative for alpha-4. Three of the tumors showed weak expression of alpha-5, two of which (a squamous cell carcinoma and a renal cell carcinoma) were the tumors that showed the greatest adhesion to fibronectin. Quantitative adhesion data can be obtained using cell suspensions prepared from fine-needle aspirates, and there are marked differences in adhesive properties between particular tumors. Although two of the tumors showed a correlation between adhesion to fibronectin and immunohistochemical expression of the alpha-5 integrin subunit, matrix adhesion does not necessarily correlate with immunohistochemical expression of adhesion molecule receptors. In the future, this methodology potentially could be of value in determining which patients may benefit from therapies aimed at modifying tumor cell-matrix interactions.

Mixed mode fracture criterion of interface crack between dissimilar materials

This study presents an application of fracture mechanics to the interface crack between dissimilar materials. In this study, a concept of the stress intensity factors of an interface crack is discussed, and various types of specimens are tested experimentally for investigating the mixed mode fracture toughness criterion of an interface crack. The fracture toughness based on the stress intensity factors of an interface crack is decided by the fracture test and the boundary element analysis using the contour integral method. The mixed mode fracture toughness criterion is successfully characterized by the stress intensity factors of an interface crack.

The rate of corrosion of hardened cement pastes and mortars with additive of silica fume in acids

The rate of corrosion of hardened cement pastes (HCPs) and cement mortars in solutions of nitric acid and acetic acid were compared. Cement mortars were prepared with a different sand-to-cement ratio and fineness of sand. A study on the effect of silica fume on corrosion resistance of cement paste and mortars to acid solutions is also presented. The progress of corrosion was expressed in terms of depth of corrosion related to duration of acid attack. The rate of corrosion of all types of specimens was faster in nitric acid solution than in solution of acetic acid with the same concentration. Cement mortars corroded at a slower rate than HCPs, though the difference was minor. There was also some small difference between the rate of corrosion of different mortars. Corroded layers of cement mortars contained smaller, less observable cracks and shrank less than corroded layers of cement pastes. Addition of silica fume slightly reduced the corrosion rate of both HCP and mortar. The differences in the corrosion rate between various types of specimens were smaller in acetic acid than in nitric acid solutions. The specimens lost weight due to acid attack. Loss of weight per unit volume of cement pastes or mortars increased with the increase of the cement content.

B-cell gene rearrangement in benign and malignant lymphoid proliferations of mucosa-associated lymphoid tissue and lymph nodes

The polymerase chain reaction (PCR) with polyacrylamide gel electrophoresis was used to study patterns of immunoglobulin heavy chain (IgH) gene rearrangement (GR) in formalin-fixed, paraffin-embedded specimens of lymphomas and reactive conditions of mucosa-associated lymphoid tissue (MALT) and lymph nodes. DNA amplification was performed directly on sections obtained from paraffin blocks. Five patterns of PCR products were observed: a single band, two or more discrete bands, smearing, a single band overlying a smear, and two or more bands over a smear. A pure polyclonal pattern (smear) was observed in all of the reactive lymph nodes but in only 15% of cases of Helicobacter pylori (HP) gastritis with lymphoid hyperplasia, 25% of cases of HP gastritis without lymphoid hyperplasia, and 37% of colonic specimens of various types. Patterns consisting of multiple bands with or without background smearing were common in gastritis, colitis, and gastric lymphomas. Single bands or dominant bands were present in all lymph node and salivary gland lymphomas, 12 of 14 cases of gastric lymphoma, and 17 of 20 cases of HP gastritis with lymphoid hyperplasia. These bands were reproducible in deeper sections from the same paraffin block or similar areas sampled in different blocks in all of the lymph node and salivary gland lymphomas, 11 of 12 gastric lymphomas, but only 1 of 17 cases of HP gastritis with lymphoid hyperplasia. Bands were also found in 3 of 20 cases of HP gastritis without lymphoid hyperplasia and 17 of 38 colonic specimens, but these were not reproducible. The complexity of patterns of IgH GR in acquired MALT compared with lymph nodes may be the result of a relative paucity of B-cell clones or preferential proliferation of B-cell clones with a limited area of distribution.

Electron crystallography.

The idea of solving unknown crystal structures from experimental electron-diffraction intensities and high-resolution electron micrographs has remained a controversial topic in the 60 year history of electron crystallography. In this review it will be shown that the application of modern direct phasing techniques, familiar to X-ray crystallographers, has decisively proven that such ab initio determinations are, in fact, possible. This statement does not, by any means, refute the existence of the several significant scattering perturbations identified by diffraction physicists. Rather, it does affirm that experimental parameters can be controlled to ensure that a 'quasi-kinematical' data set can be collected from many types of specimens. Numerous applications have been made to various types of specimens, ranging from small organics to proteins, and also some inorganic materials. While electron crystallography may not be the optimal means for determining accurate bonding parameters, it is often the method of choice when only microcrystalline specimens are available.