Laboratory Testing Techniques Research Articles

Shear wave velocity-based assessment of liquefaction resistance of natural pumiceous sands

Over the last few decades, a number of laboratory and field testing techniques have been developed to evaluate the liquefaction resistance of hard-grained sands, while very few investigations have been performed on crushable volcanic soils. Natural pumiceous (NP) soils, a type of volcanic soil commonly found in the North Island of New Zealand, are problematic due to their crushability and lightweight features. Therefore, questions have been asked as to whether existing empirical correlations for liquefaction assessment derived primarily from hard-grained sands would be applicable to NP sands. Previous investigations on crushable soils indicate that penetration methods would not provide reliable estimates of their cyclic resistance ratio (CRR) due to particle crushing occurring during penetration. Thus, the measurement of shear wave velocity (Vs) may be a promising alternative for liquefaction assessment of NP sands. In this paper, a number of cyclic triaxial and bender element tests were conducted on reconstituted NP sands to estimate their CRR and Vs, respectively. The laboratory results indicated that, for the same relative density and effective confining pressure, NP sands have considerably lower Vs and higher CRR compared with hard-grained sands. Thus, using currently available CRR–Vs curves developed for hard-grained sands would result in significant underestimation of the liquefaction resistance of NP sands.

Laboratory analysis to assess shale stability for the Zubair Formation, Southern Iraq

The Zubair Formation consists of approximately 55% shale, which causes almost 70% of wellbore problems due to incompatibilities between drilling fluids and shale formations. The most common and effective solution to shale instability is through the design and selection of appropriate drilling fluids. Understanding the interaction between drilling fluids and shale has been a challenge due to the complexity of both the physical and chemical variations in shale formations. This paper presents some of the primary laboratory and wellsite testing techniques that are often used by mud engineers to characterize and remediate drilling fluids and shale interactions. Well-preserved core samples retrieved from the Zubair shale formation in Southern Iraq were run through extensive testing to describe the special characterization of the Zubair shale. These characteristics were measured and described, including the structure, texture, mineralogy, and reactivity, using a scanning electron microscope (SEM), a thin-section photograph, X-ray diffraction analysis (XRD) imaging, and cation exchange capacity (CEC) analysis. Moreover, a capillary suction timer (CST), hot rolling dispersion test, bulk hardness test, linear swell meter (LSM), and fracture development test were used to evaluate the stability of shale in the presence of test fluids. The test fluids included fresh water, 20 wt% NaCl brine, 7 wt% KCl brine, and a combination of 7 wt% KCl and 3 vol% glycol. The results illustrated that the Zubair shale is composed mainly (average content of 51.46%) of brittle minerals (i.e., quartz and calcite), along with 43.54% of clay minerals. The predominant clay minerals were kaolinite and illite, with an average content of 48.06% and 34.71%, respectively. In addition, the cation exchange capacity analysis and capillary suction time test indicated that Zubair shale has a low-to-moderate reactivity with drilling fluids. Furthermore, among the fluid systems tested, the best shale inhibition was achieved when the 7 wt% KCl and 3 vol% glycol solution was used. Shale sample analyses methods were used to understand the geologic features of the Zubair shale formations and to achieve a better perspective on the potential interactions of shale formations with drilling fluids. Understanding the properties and responses of shale formations to fluids is a significant step in achieving the chemical clay stabilization objectives. Proper design of drilling fluids, with appropriate mud weight and suitable additives, can lead to substantial cost reduction in drilling operations.

Shale pore size classification: An NMR fluid typing method

Abstract Shale reservoir is characterized by complex pore networks, within which there are various pore fluids including unrecoverable fluid, capillary bound fluid and movable fluid. Although considerable literature has investigated the pore structure of gas shale using different laboratory testing techniques, few papers have provided a quantified model to distinguish different types of fluids (corresponding to different pore types) in shale. In this study, seven shale core plugs from the Sichuan Basin were measured in a series of NMR experiments under full brine-saturated, centrifugal and heat-treated conditions to analyze the pore structure information and pore fluid transport during the processes of centrifuging and heating. For a typical T2 spectrum of 100% brine-saturated shale, the movable fluid T2 cutoff (T2C1) and unrecoverable fluid cutoff (T2C2) were derived from NMR centrifugal and heat-treated experiments to distinguish the unrecoverable fluid (T2 T2C1). Our results show that for the investigated shales, the T2C2 ranges from 0.09 ms to 0.36 ms, and T2C1 has a wide range from 0.45 ms to 2.98 ms. The surface relaxivities range from 0.00426 μm/ms to 0.02822 μm/ms, and the shales having high silicate mineral contents commonly have low surface relaxivities. A conceptional model based on the dual T2 cutoff method was constructed to illustrate the full-scale pore size distribution: unrecoverable fluid pores, capillary bound fluid pores and movable fluid pores. This study provides a new method of pore fluid typing and full-scale pore size distribution classification for shales.

Catalytic Cracking of Light Crude Oil to Light Olefins and Naphtha over E-Cat and MFI: Microactivity Test versus Advanced Cracking Evaluation and the Effect of High Reaction Temperature

The catalytic cracking of light paraffinic crude oil with an API gravity of 51° was compared using two laboratory testing techniques, a fixed-bed microactivity test (MAT) unit and a fixed fluidized-bed advanced cracking evaluation (ACE) unit. Both units were operated using equilibrated FCC catalyst (E-Cat), MFI zeolite (ZSM-5), and E-Cat/MFI (equal mixture with MFI) at two temperatures (550 and 600 °C) and a constant catalyst-to-oil ratio of 4.0. Despite the different hydrodynamics in MAT and ACE reactors, both units gave similar catalyst ranking based on the conversion of 221+ °C feed fraction at 550 and 600 °C in the order of E-Cat > E-Cat/MFI > MFI, which is attributed to diffusion limitation of MFI catalyst. While both testing techniques showed variation in product yield structure (dry gas, LPG, naphtha, and unconverted 221+ °C) over the three catalysts, the ACE unit gave significantly higher coke yield compared with MAT. The highest yield of light olefins was obtained over E-Cat/MFI (29 wt %) at 600 ...

Abstract P3-05-02: Quantitative ERα measurements in TNBC from the I-SPY 2 TRIAL correlate with HER2-EGFR co-activation and heterodimerization

Abstract Background: We have previously described that TNBC patients whose tumors have both HER2 Y1248 phosphorylation (pHER2) “high” and phospho-EGFR Y1173 (pEGFR) “high” have increased response (pCR) to neratinib in the I-SPY2 TRIAL. We hypothesize that the paradoxical finding of a response prediction signature comprised of HER2 activation in a HER2 IHC/FISH-negative population means there must be a ligand-driven biochemical event responsible for the HER2 phosphorylation because HER2 mutations were also not found to be significant. Exploratory analysis of additional cellular signaling events and protein expression levels in pre-treatment, LCM-purified tumor epithelium by reverse phase protein microarray (RPPA) included semi-quantitative measurement of total levels of estrogen receptor alpha (ERα), which has been previously shown to be able to act as a membrane non-genomic signaling molecule through direct interaction with various tyrosine kinases including EGFR and HER2. Since ERα has been previously shown to act as a ligand and co-stimulate (activate) HER2 and EGFR when present at low levels, we investigated whether or not RPPA-measured ERα levels in the TNBC cohort analyzed to date were higher in tumors with both pHER2 “high” and pEGFR “high” levels and thus provide evidence explaining how HER2-EGFR activation is occurring in TNBC. Methods: Using RPPA analysis, we measured 118 analytes in lysates of LCM tumor epithelium obtained from the pre-treatment biopsy samples of 86 TNBC (Allred=0) patients in the I-SPY2 TRIAL analyzed to date. Cutpoints for pEGFR and pHER2 were determined previously by ROC analysis for pCR correlation in the neratinib treated TNBC population, and used here to dichotomize the pHER2 and pEGFR data in the larger TNBC population. Wilcoxon Rank Sum testing was performed using the continuous variable total ERα data and compared the TNBC that were both pHER2 and pEGFR “high” (N=39) to the rest of the TNBC population (N=47). Total ERα values were then divided into “high” and “low” groups based on the TNBC population median value in order to determine frequency/percentages within each class. Our study is exploratory with no claims for generalizability of the data, and calculations are descriptive (e.g. p-values are measures of distance with no inferential content). Results: Total ERα values were obtained in 84/86 TNBC tumors analyzed. Total levels of ERα were higher (p< 0.006) in TNBC tumors with pHER2 and pEGFR “high” levels. 68% (26/38) of tumors in the pHER2 and pEGFR “high” group had ERα levels above the population median compared to 35% (16/46) in the rest of the TNBC population. Conclusion: Our exploratory analysis reveals that ERα levels are significantly higher in TNBC with pHER2 and pEGFR activation and may be behaving as a direct signaling ligand in TNBC and driving HER2-EGFR signaling. This ERα-pHER2/pEGFR association was missed by current ER and HER2 clinical laboratory testing techniques, and if validated in larger independent study sets could suggest that utilization of new protein-based techniques defining ER more quantitatively could be helpful to understand tumor biology and therapeutic response prediction, especially in the context of TNBC that are ostensibly ER negative. Citation Format: Gallagher RI, Yau C, Wolf DM, Dong T, Hirst G, Brown-Swigart L, ISPY-2 TRIAL Investigators, Buxton M, DeMichele A, van't Veer L, Yee D, Paoloni M, Esserman L, Berry D, Park J, Petricoin EF, Wulfkuhle JD. Quantitative ERα measurements in TNBC from the I-SPY 2 TRIAL correlate with HER2-EGFR co-activation and heterodimerization [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P3-05-02.

Bone Marrow Metastases as an Initial Presentation of Gastrointestinal Adenocarcinoma: A Case Report

Bone marrow metastases as the initial presentation of a solid tumour are uncommon, especially if the primary neoplasm site cannot be identified during the diagnosis presentation despite laboratory testing and imaging techniques. In these situations, bone marrow examination can lead to a final diagnosis of the primary malignancy. We report an unusual case of osteoblastic metastases from an unknown primary site – this was because no relevant lesions were found from either imaging or endoscopic examination. The patient was sent for a bone marrow biopsy, revealing a morphology replaced by glandular structures and an immunohistochemistry consistent with a gastrointestinal origin. Bone marrow examination was the clue to the final diagnosis and led to specific treatment.

Molecular and Imaging Diagnostic Techniques for Urinary Tract Infections: Modern Approaches

In developing countries, the frequent failure of the available phenotypic approaches for laboratory diagnosis of urinary tract infections in providing results at the point where medical care is mostly required, becomes a major barrier to efficient antibiotic treatment and management of urinary tract infections in the public health sector. This review therefore focuses on molecular and imaging diagnostic techniques for urinary tract infection as rapid and effective modern approaches requires in health care delivery. Currently, available laboratory diagnoses of urinary tract infection in developing countries are mostly phenotypic approaches, and takes not less than two-four days before completion and result made available for appropriate treatment. From literature, it is apparent that these old-century approaches produce portion of patients’ result that does not fit the true picture; and the techniques had been found with more disadvantages than advantages. Molecular approaches are now emerging as modern laboratory test techniques which enable rapid and effective diagnosis of urinary tract infection with Biosensor, Microfluidics, Polymerase Chain Reaction (PCR) and other integrated platforms technologies. These emerging technologies could improve urinary tract infection diagnosis via direct pathogen detection from urine samples, rapid antimicrobial susceptibility testing, high precision and point of care testing in public health sector. Imaging techniques have also been so useful in identifying risk factors and abnormalities that can be modified; to decrease likelihood of recurrent (upper) UTI; and to reduce risk of renal scarring. These approaches however, had proved so successful that seems they will replace old-century testing methods, and hence, provides efficient antibiotic treatment and management; therefore, saving health care costs and valuable diagnosis time.

Reliability of clinical diagnosis and laboratory testing techniques currently used for identification of canine parvovirus enteritis in clinical settings.

Canine parvovirus type 2 (CPV-2) is the main etiological agent of viral enteritis in dogs. Actually in literature, CPV-2 has been reported with clinical signs that vary from the classical disease, and immunochromatography test and PCR technique have been introduced to veterinary hospitals to confirm CPV-2 diagnosis and other infections. However, the reliability of these techniques has been poorly analyzed. In this study, we evaluated the sensitivity and specificity of veterinary clinical diagnosis, immunochromatography test and PCR technique. Our data indicate that variations in the clinical signs of CPV-2 complicate the gathering of an appropriate diagnosis; and immunochromatography test and PCR technique do not have adequate sensitivity to diagnose positive cases.

Should the non-operative management of appendicitis be the new standard of care?

Appendicitis is one of the most commonly encountered emergency presentations to the general surgical services. The operative management of this condition is associated with significant financial costs and represents a significant workload on the emergency surgical services. Negative appendicectomy rates remain high (20-25%) despite advancements in laboratory testing and imaging techniques. Recent data from randomized controlled trials suggests that non-operative management in patients presenting with uncomplicated or non-perforated acute appendicitis is a viable alternative, with only 23% of patients requiring an appendicectomy at 1 year and an overall reduction in complications. In view of this, the traditional teaching of mandatory appendicectomy for all patients with acute appendicitis should be challenged. This article briefly reviews the evidence that supports the use of diagnostic tests to reduce the negative appendicectomy rate and examines the potential selection criteria for non-operative management. The data raises the questions: can a 20-25% negative appendicectomy rate be defended as best practice and can the traditional dogma of early appendicectomy to prevent perforation be supported?

Cyclic plastic deformation characteristics of subgrade under moving train wheel load

Cyclic plastic deformation of subgrade and other engineered layers is generally not taken into account in the design of railway bridge transition zones, although the plastic deformation is the governing factor of frequent track deterioration. Actual stress behavior of fine grained subgrade/embankment layers under train traffic is, however, difficult to replicate using the conventional laboratory test apparatus and techniques. A new type of torsional simple shear apparatus, known as multi-ring shear apparatus, was therefore developed to evaluate the actual stress state and the corresponding cyclic plastic deformation characteristics of subgrade materials under moving wheel load conditions. Multi-ring shear test results has been validated using a theoretical model test results; the capability of the multi-ring shear apparatus for replicating the cyclic plastic deformation characteristics of subgrade under moving train wheel load conditions is thus established. This paper describes the effects of principal stress rotation (PSR) of the subgrade materials to the cyclic plastic deformation in a railroad and impacts of testing methods in evaluating the influence of principal stress rotation to the track deterioration of rail track.

Assessing the awareness mechanisms of a collaborative programming support system

The learning and teaching of Programming can benefit from the principles of Computer Supported Collaborative Learning (CSCL). With that purpose in mind, the COLLECE system was created to support synchronous collaborative programming in learning settings. Unlike other systems with similar objectives, COLLECE incorporates many elements to support group awareness. This article presents an empirical study in which the usefulness of some of the awareness mechanisms included in this system is evaluated. One of the main contributions of this work is the combination of different techniques to evaluate interactive systems, such as questionnaires, laboratory testing, heuristic evaluation, automatic logging and eye tracking techniques. The joint use of these techniques (of both a subjective and objective nature) allows us to carry out a more complete analysis of the system under study and, in particular, about its support of awareness.

Geoenvironmental Application of Bentonites in Underground Disposal of Nuclear Waste: Characterization and Laboratory Tests

In the context of underground storage of nuclear waste, this paper presents the characterization and laboratory tests on compacted MX80 bentonite. Various laboratory testing techniques were used for establishing the water retention behavior of the bentonite. Compacted bentonite specimens were hydrated with fluids of low and high salt concentrations both at ambient and an elevated temperature of 70°C. The swelling behavior of the bentonite was also studied by stepwise wetting compacted specimens at various suctions under isochoric condition. The influence of thermal and thermohydraulic gradients on the mechanical behavior of the bentonite was studied in a thermohydraulic column cell. The investigation showed that the development of swelling pressure in compacted bentonites upon a decrease in the applied suction is accompanied by a decrease in the magnitude suction stress, which gets manifested in the development of the interparticle repulsive pressure and a decrease in the effective stress. The influence of an elevated temperature and an increase in concentration of salt in the hydrating fluid was found to reduce the swelling pressure of the bentonite. Both thermal and thermohydraulic gradients were found to be manifested on the development of axial pressures. Applications of thermal and thermohydraulic gradients were found to cause redistributions of water content, dry density, degree of saturation, and suction within compacted bentonites.

Examination of the Potential of the Seismic Dilatometer (SDMT) to Estimate In Situ Stiffness Decay Curves in Various Soil Types

This paper illustrates the use of the seismic dilatometer (SDMT) to assess the decay of in-situ stiffness with strain level in different soil types. The approach adopted in this study relies on the ability of the SDMT to provide routinely at each test depth both a small strain stiffness (G0 from VS ) and a working strain stiffness (constrained modulus MDMT derived from the usual DMT interpretation). At various test sites, working strain DMT moduli are compared with reference stiffness decay curves back-figured from (i) the behavior observed under a full-scale test embankment (at Treporti) or footings (in Texas), (ii) from laboratory tests (at L’Aquila, Fucino plain and Po plain) and (iii) various combinations of insitu and laboratory testing techniques (Western Australia). Typical ranges of the shear strains DMT associated with working strain DMT moduli are inferred to assist construction of stiffness - strain decay curves for different soil types.

Retrospective analysis of 50 cases of senile syphilis

To summarize the epidemiological features of senile syphilis. The clinical data of 50 elderly (>60 years) patients with syphilis who were treated in the Clinic of Sexually Transmitted Diseases of Peking Union Medical College Hospital were retrospectively analyzed. There were 31 men and 19 women (male to female ratio:1.6:1). Non-marital sexual intercourse was the main route of transmission. The disease was mainly found before surgeries. Among these 50 syphilis cases, 3 were primary syphilis, 13 were secondary syphilis, 10 were early latent syphilis, 12 were late latent syphilis, and 12 were latent syphilis of unknown duration. Co-morbidities with other sexually transmitted diseases were found in 4 patients. The rate of sero-resistance was 40%. The incidence of syphilis in the senile population is higher than we expected. Routine serological screening for syphilis is required in clinical settings. The underlying diseases, human hosts-related spirochetes, and laboratory testing techniques are important reasons for the false positive findings in senile patients.

Enhancing Surveillance for Arboviral Infections in the Arizona Border Region

The goal of this project is to enhance surveillance for Arboviruses by establish a baseline for the emerging threat of Dengue fever the border region of Arizona. This will be accomplished by: enhancement and exchange of dengue laboratory testing techniques, a seroprevalence sentinel-hospital site study of symptomatic patients, and mapping techniques to better understand the presence of mosquito vectors.

Identification of Designer Drug 2C-E (4-Ethyl-2, 5-Dimethoxyphenethylamine) in Urine Following a Drug Overdose

In recent years, access to information regarding acquisition and synthesis of newer designer drugs has been at an all-time high due largely to the Internet. As these drugs have become more prevalent, laboratory techniques have been developed and refined to identify and screen for this burgeoning population of drugs. This provides a unique opportunity for learning about many of these methods. Laboratory testing techniques and instrumentation are obscure to many health care professionals, yet their results are crucial. Here, we present a case of an overdose of an uncommon designer drug (2C-E) and discuss the basics of liquid chromatography and mass spectrometry, two important techniques used in isolating and identifying the drug. Although often overlooked and taken for granted, these techniques can play a pivotal role in the diagnosis and subsequent management of select patients.

Unstable behaviour of model Jamuna micaceous sand

(a) A specimen can collapse under a drained condition if the test is conducted under a load-controlled loading mode as shown and discussed in detail by Chu & Leong (2003a, 2003b) and Chu & Wanatowski (2009). (b) By confining the conclusion to ‘fully drained conditions’, the discussers would assume that the author considers that instability under ‘fully undrained conditions’ involves collapse or loss of strength. This is also an observation made by a number of researchers (e.g. Lade & Pradel, 1990; Lade, 1992, 1993; Sasitharan et al., 1993; Leong et al., 2000; Chu & Leong, 2003a, 2003b; Chu et al., 1993, 2003; Chu & Wanatowski, 2009). As the author did not specify otherwise, the discussers assume that the term ‘drained’ is used to refer to a condition where water is allowed to flow in or out of the specimen under a constant back pressure condition. Under such drained condition, the effective confining stress or the effective stress path can be controlled by varying the cell pressure. With today’s laboratory testing techniques, it is possible to carry out a special ‘drained’ triaxial test to trace the curved effective stress path followed in an undrained test in which the specimen has collapsed. Assume this special test is conducted under a load-controlled loading mode, would the specimen in this test collapse or not? If it would, then this collapse is under a drained condition. If it would not, then what are the other factors that control the collapse in addition to the effective stresses?

Laboratory Hydraulic Testing in Unsaturated Soils

This paper synthesizes the state-of-the art of the various laboratory testing techniques presently available for measuring the water hydraulic constitutive functions of unsaturated soils. Emphasis is on the laboratory testing techniques for measuring the soil–water retention curves and the water hydraulic conductivity functions of unsaturated soils. The significant recent advances in the investigation of the hydraulic behaviour of unsaturated swelling soils, are also presented. Comprehensive recent references on each measurement method are listed and discussed.

Chromite Ore Processing Residue (COPR): Hazardous Contaminated Soil or Solid Waste?

Abstract Chromite ore processing residue (COPR), which contains hexavalent chromium (Cr6+) at concentrations typically in the range of thousands of milligrams/kilograms, was deposited over a timeframe of 50 years as fill at a site referred to as SA7 in New Jersey. Significant surface heaving associated with COPR weathering-induced mineralogical expansion has been observed at the site over time. The current site owner is being required to remediate the site to mitigate both human health risks associated with the Cr6+ and site redevelopment problems associated with COPR heave. The owner is presently required to remediate the COPR by excavation and off-site disposal at a licensed hazardous waste landfill. This is a very expensive remediation option, one that may not be financially sustainable at other COPR impacted sites. The owner has undertaken a major investigation to better characterize the nature of COPR and to develop on-site treatment technologies to reduce Cr6+ concentrations and mitigate COPR heave potential. As one part of the investigation, the characteristics of COPR were evaluated with respect to the definitions of hazardous contaminated soil and hazardous solid waste under the toxicity characteristic waste provisions of the U.S. Resource Conservation and Recovery Act (RCRA). Remediation clean-up standards, and thus the potential costs and applicable methods associated with site remediation, under these two definitions are significantly different. This paper explains these differences and evaluates the COPR for conformance with each definition. This evaluation includes comparison of sampling, logging, and laboratory testing techniques for COPR compared to soil, geotechnical parameter comparisons, and mineralogical and total metals comparisons. Based on these comparisons, the authors conclude that COPR should classify as a hazardous contaminated soil from both regulatory and scientific perspectives. The bases for this conclusion are provided in the paper. The methodology presented herein to evaluate COPR classification may have applicability to other contaminated soil-like media from industrial processes that are potentially subject to the requirements of RCRA hazardous waste regulations or similar regulations in other countries.

Slow strain rate testing for monitoring cracking of mild steels for vessels and pipes for processing using caustic solutions

Caustic cracking is a major infrastructure and safety concern in mild steel digesters, pipelines, refining and storage vessels in alumina processing and paper industries. This paper investigates application of slow strain rate (SSR) testing as a laboratory method to characterize caustic cracking susceptibility of mild steels. SSR tests were carried out at 120 °C in 200gpl NaOH at different strain rates (1.7×10 −7 to 16×10 −7 s −1). The results suggest that the mild steel is susceptible to caustic cracking in a very narrow window of strain rates (around 3×10 −7 s −1). This study also supports SSR testing as a dependable laboratory testing technique for further studies.