Advanced Laboratory Research Articles

A novel diffraction contrast tomography (DCT) acquisition strategy for capturing the 3D crystallographic structure of pure titanium

The acquisition of high-fidelity 3D grain maps is essential for advancing our understanding of the micromechanical behavior of polycrystalline materials. Grain orientations, grain boundary misorientations, and grain shapes play a significant role in slip transfer mechanisms and grain growth phenomena. The past few years have seen considerable advances in the acquisition of high-reliability grain maps using laboratory-based Diffraction Contrast Tomography (LabDCT). Additionally, the microstructures of challenging sample geometries have become more accessible at the lab scale with recent developments in advanced Lab DCT acquisition strategies, such as helical phyllotaxis Lab DCT (HP-DCT). Unlike a conventional Lab DCT (C-DCT) scan, in which an elongated sample is scanned in multiple sections, a helical phyllotaxis motion is employed in an HP-DCT scan to illuminate the different parts of the sample in a single scan. This strategy can theoretically allow to scan and reconstruct challenging sample geometries, such as elongated and high aspect ratio samples, in a single process with fewer diffraction projections and reduced scan and analyses times. In this study, a detailed analysis of the grain maps for a pure Ti sample obtained from C-DCT and HP-DCT scan data is carried out. The DCT grain maps are compared with the surface grain maps obtained from ground-truth EBSD and SEM scans. Furthermore, the quality of grain reconstructions, grain orientations, grain boundary misorientations, grain shapes and morphology is quantitatively assessed, and the differences in accuracy of grain maps obtained from the conventional and helical phyllotaxis scans are highlighted. These results indicate that the grain reconstructions from HP-DCT scans have comparable grain fidelity to those obtained from C-DCT scan, with the conventional scans performing marginally better in terms of grain shape and orientation but at a higher time cost.

The Horizontal Mode Natural Frequency of a Floating Pile in Layered Soil: Full-Scale Field Test Vs Mathematical Models

Pile supported structures can be subjected to a variety of man-made and naturally occurring dynamic loads. Dynamic loads such as those from rotating machinery include a considerable lateral component. The natural frequency of a pile in the horizontal mode becomes a key parameter in the design of dynamically sensitive equipment foundations. It is not uncommon for structural engineers to estimate the natural frequency of piles using quick linear methods using available soil investigation data before advanced laboratory tests on soil samples can be performed to calibrate nonlinear numerical models. This paper presents results from free and forced vibration tests on a full-scale single pile, designed for a high-speed compressor unit, in Hazira, India. Two different fast mathematical models, one following the Beam on Dynamic Winkler Foundation (BDWF) method, and another involving an FEM–BEM based numerical method were used in predictions against experimental results. The BDWF method was found to produce a preliminary estimate of pile stiffness at low strain levels. However, the selection of soil stiffness and damping models are crucial for the accuracy of BDWF models. It was found that the FEM–BEM model was able to simulate the nonlinear pile response with a moderate overestimation of vibration amplitudes.

Marine litter colonization: Methodological challenges and recommendations

Marine litter colonization by marine invertebrate species is a major global concern resulting in the dispersal of potentially invasive species has been widely reported. However, there are still several methodological challenges and uncertainties in this field of research. In this review, literature related to field studies on marine litter colonization was compiled and analyzed. A general overview of the current knowledge is presented. Major challenges and knowledge gaps were also identified, specifically concerning: 1) uncertainties in species identification, 2) lack of standardized sampling methodologies, 3) inconsistencies with the data reported, and 4) insufficient chemical-analytical approaches to understand this phenomenon. Aiming to serve as a guide for future studies, several recommendations are provided for each point, particularly considering the inaccessibility to advanced techniques and laboratories.

Pharmacogenomics elective focused on advanced lab techniques, game-based learning, and business plan development

Background and purposeMany medications contain labeling information related to pharmacogenomics. Effective education in this area is critical to ensure that future healthcare professionals are equipped with the skills needed to optimize patient therapy based on genetic testing results. This study focused on a novel elective course designed to educate students in pharmacogenomics. Educational activity and settingWe developed a one credit hour pharmacogenomics elective course divided into three main content areas. The first section incorporated traditional lecture to review and cover new content not otherwise covered in the curriculum. The second section applied foundational content from the first session through an educational review game and simulated business plan. The third section of the course provided students an overview of laboratory techniques and sample collection procedures. To evaluate the effectiveness of these activities, students provided feedback through course evaluations and completed pre- and posttests on basic pharmacogenomics content. FindingsOverall, the course improved knowledge among students, and students provided positive feedback. Students averaged 9% higher on the posttest compared to the pretest (P = .03). Course evaluations trended positive with ratings close to “strongly agree.” The most frequent comments stated an appreciation for the interactive components of the course and recommended increasing the elective to two credit hours. SummaryThrough incorporation of novel lab techniques, game-based learning, and an innovative business plan process, the course increased student knowledge and received positive feedback. These new techniques could serve as a model for other pharmacogenomics training programs.

A Modern Experiment for Old Concepts: A Supramolecular Transient System

Scientists have always been fascinated by transient far-from-equilibrium systems. Since the (early) 1970s, there have been literature reports on the implementation of didactic experiments as a tool for attracting and stimulating students’ and general public interest. In this work, a group of 12 high school students, supported by their chemistry teacher, have developed a supramolecular system formed by gold nanoparticles functionalized with a positively charged thiol group. The positively charged nanoparticles were aggregated by adding polyanionic ATP as fuel. Aggregates were determined by UV–vis spectroscopy. Disaggregation was realized by adding an enzyme capable of hydrolyzing the ATP P–O bonds. The lifetime of the aggregates depends on the enzyme concentration and efficiency. Several aggregation–disaggregation cycles were performed. Students were divided into three groups, each of four students. Teachers assigned different duties to each group. The first group synthesized and purified the gold nanoparticles and the capping thiolic group. The second group determined UV–vis optical properties of the nanosystem and implemented the conditions for further experiments. The third group performed experiments to characterize the nanosystem and its lifetime. At the time of this activity, all of the students were attending their last year at chemistry high school in Italy. As didactic goals, they have been trained in problem solving, the use of advanced lab instruments, and following and projecting their own research activity.

High Prevalence of Sexually Transmitted and Reproductive Tract Infections (STI/RTIs) among Patients Attending STI/Outpatient Department Clinics in Tanzania.

The patients were consecutively recruited, and the data collection was conducted in eight health care facilities from 2014 to 2016. Genital swabs were collected for the detection of the aetiological pathogens of STI/RTIs. A total of 1243 participants were recruited in the study; the majority (1073, 86%) were women. The overall median age was 27.8. The prevalence of Neisseria gonorrhoeae was 25.7% (319/1243), with proportions of 50.9 and 21.5% for men and women, respectively, of Chlamydia trachomatis 12.9% (160/1241) and Mycoplasma genitalium 4.7% (53/1134). Unmarried men were more often likely to be infected with gonococcal infections as compared to their women counterparts (57.9 vs. 24.1%) p < 0.001. The majority presented with genital discharge syndrome (GDS) 93.6% (1163/1243), genital ulcer disease (GUD) 13.0% (162/1243) and GDS + GUD 9.6% (119/1243). GDS was more common in the health centres, 96.1% (1195/1243), vs. the regional referral hospitals, 92.2% (1146/1243) (p = 0.01), but those reported to the regional referral hospitals were more likely to be infected with N. gonorrhoeae (OR = 2.5) and C. trachomatis (OR = 2.1) than those from the health centres (p < 0.001). The prevalence of bacterial vaginosis (BV) and vaginal candidiasis (VC) was 24.1 and 10.4%, respectively. Interestingly, unmarried and BV-positive women were less likely to be infected with VC (p = 0.03), though VC was strongly inversely associated with an N. gonorrhoeae infection (p < 0.001). High proportions of N. gonorrhoeae (51.1%) and C. trachomatis (23.3%) were found in the Dodoma and Dar es Salaam regions, respectively. M. genitalium (7.6%) was found to be the highest in Mwanza. We reported a high prevalence of STI/RTIs. The findings suggest that these infections are common and prevalent in STI/OPD clinics in six regions of Tanzania. We recommend surveillance to be conducted regularly to elucidate the true burden of emerging and classical STI/RTIs by employing modern and advanced laboratory techniques for the detection and monitoring of STI/RTIs in low- and high-risk populations, including the community settings.

Comprehensive Comparison of Seven SARS-CoV-2-Specific Surrogate Virus Neutralization and Anti-Spike IgG Antibody Assays Using a Live-Virus Neutralization Assay as a Reference.

Neutralizing antibodies (nAbs) are considered a valuable marker for measuring humoral immunity against SARS-CoV-2. However, live-virus neutralization tests (NTs) require high-biosafety-level laboratories and are time-consuming. Therefore, surrogate virus neutralization tests (sVNTs) have been widely applied, but unlike most anti-spike (S) antibody assays, NTs and sVNTs are not harmonized, requiring further evaluation and comparative analyses. This study compared seven commercial sVNTs and anti-S-antibody assays with a live-virus NT as a reference, using a panel of 720 single and longitudinal serum samples from 666 convalescent patients after SARS-CoV-2 infection. The sensitivity of these assays for detecting antibodies ranged from 48 to 94% after PCR-confirmed infection and from 56% to 100% relative to positivity in the in-house live-virus NT. Furthermore, we performed receiver operating characteristic (ROC) curve analyses to determine which immunoassays were most suitable for assessing nAb titers exceeding a specific cutoff (NT titer, ≥80) and found that the NeutraLISA and the cPass assays reached the highest area under the curve (AUC), exceeding 0.91. In addition, when the assays were compared for their correlation with nAb kinetics over time in a set of longitudinal samples, the extent of the measured decrease of nAbs after infection varied widely among the evaluated immunoassays. Finally, in vaccinated convalescent patients, high titers of nAbs exceeded the upper limit of the evaluated assays' quantification ranges. Based on data from this study, we conclude that commercial immunoassays are acceptable substitutes for live-virus NTs, particularly when additional adapted cutoffs are employed to detect nAbs beyond a specific threshold titer. IMPORTANCE While the measurement of neutralizing antibodies is considered a valuable tool in assessing protection against SARS-CoV-2, neutralization tests employ live-virus isolates and cell culture, requiring advanced laboratory biosafety levels. Including a large sample panel (over 700 samples), this study provides adapted cutoff values calculated for seven commercial immunoassays (including four surrogate neutralization assays and a protein-based microarray) that robustly correlate with specific titers of neutralizing antibodies.

A Comparative Study of Plant Extracts and Biocontrol Agents for Managing Alternaria burnsii in Cumin (Cuminum cyminum L.): An In-vitro Assessment

The objective of the current study was to assess the in-vitro efficacy of plant extracts and bio-agents in managing Alternaria burnsii, the causal agent of blight disease in cumin. Eleven plants extract were selected based on their availability in the local region and evaluated for antifungal activity in the laboratory for their effectiveness against A. burnsii. Plants extract was tested at four different concentrations 5%, 10%, 15% and 20% each by food poisoning technique. Additionally, four bio-agents, namely Trichoderma harzianum, T. viride, Pseudomonas fluorescens and Bacillus subtilis were evaluated against A. burnsii. The experiments were conducted from 2019 to 2021 at the Advanced Laboratory on Bioagents in the Plant Pathology Department, SKRAU, Bikaner. Among the plant extracts, Neem Seed Kernel Extract (NSKE) and Neem leaf extract were found to be the most effective, resulting in mean growth inhibition of 48.88 per cent and 45.85 per cent, respectively. The least per cent mean growth inhibition, 13.14 per cent, was recorded with Eucalyptus (Eucalyptus globulus). Among the four different bio-agents, Trichoderma harzianum was found to be the most effective in suppressing the growth of the pathogen, achieving a growth inhibition of 69.63 per cent. This study provides valuable insights into the use of locally available plant extracts and bio-agents for the management of cumin blight, promoting eco-friendly approaches.

Body Donation Awareness in Eastern Uttar Pradesh: A Cross-sectional Study among Medical Students, Practitioners, and Support Staff

Introduction: Cadavers play a crucial role in facilitating the study of anatomy, as a comprehensive understanding of human anatomy necessitates the dissection of human bodies. Additionally, cadavers are utilised for advanced laboratory work, workshops, and the training of surgical science postgraduates. With the rapid proliferation of medical colleges across the nation and the existing institutions striving to increase their student intake, the supply of unclaimed bodies may no longer be adequate to meet the demands of these institutions. Consequently, the necessity for voluntary body donation becomes increasingly pertinent. Aim: To assess the knowledge, attitude, and awareness regarding body donation among 1st-year MBBS students, healthcare professionals/doctors, and non teaching staff of a teaching institution in Eastern Uttar Pradesh, India. Materials and Methods: This was a cross-sectional study conducted at Varun Arjun Medical College and Rohilkhand Hospital, Banthra, Shahjahanpur, Uttar Pradesh, India. The total number of study participants (n=230) was divided into three groups: 1st-year MBBS students (n=90), healthcare professionals/ doctors (n=70), and non teaching staff (n=70). A self-designed and structured questionnaire containing 15 questions was used in the study. Data were recorded in an Excel sheet and analysed using Statistical Package for Social Sciences (SPSS) Version 26.0 (Chicago, Inc, USA). Results: In the MBBS and Doctors groups, all participants demonstrated familiarity with the study topic, while 95.7% of the non teaching group reported being unacquainted with the concept of body donation. Regarding the purpose of body donation, both MBBS students and Doctors indicated the dual purposes of organ donation/transplantation and medical teaching and research. Male respondents exhibited a notably positive attitude (96.6%) towards both purposes without reservation, while females showed a stronger inclination towards organ donation. When questioned about the procedure for donating the body, the MBBS students and non teaching staff displayed a lack of awareness regarding the process, with 89.5% of doctors being knowledgeable about the donation procedure. Conclusion: Despite the considerable level of awareness regarding body donation, there exists a notable lack of motivation, which could be addressed through effective sensitisation and education initiatives. Enhancing the scenario of insufficient body donations could be accomplished through targeted awareness campaigns utilising both print and electronic media.

Causality-Free Modeling of a Floating Wind Turbine Semisubmersible Platform with Validation Results

This paper presents an acausal modeling approach for developing a hydrodynamic module in the Control-oriented, Reconfigurable, and Acausal Floating Turbine Simulator (CRAFTS), a wind turbine simulation tool being developed by the authors, to facilitate control co-design of floating offshore wind turbines (FOWTs). The available data of the semi-submersible VolturnUS-S FOWT is incorporated into the modeling, simulation, and control demonstrations. The model is verified and validated using numerical data from industrial-standard simulation platform OpenFAST and experimental data from the Floating Offshore-wind and Controls Advanced Laboratory (FOCAL) Project. Numerical results demonstrate that the hydrodynamic module in CRAFTS can qualitatively capture loads and responses from the free decay tests, as well as the stabilizing effects of the tuned mass dampers (TMDs), which are tuned to attenuate the platform pitch resonance or the tower bending resonance.

A Review on the Cytotoxicity and Antibacterial Effect of Marine Organisms of Persian Gulf.

Marine organisms contain several natural products and bioactive compounds, including hydrolyzed proteins, antioxidant peptides, gelatin, collagen, ω-3 unsaturated fatty acids, vitamin A, vitamin D, calcium phosphate, hydroxyapatite, chitosan, lectin, and various toxins. They can inhibit diverse diseases, be used in pharmaceutical compounds, or as antibiotics and pigments. In this regard, these microorganisms are of crucial medicinal and economical importance. Thanks to new technologies and advanced laboratory methods, bioactive compounds can be extracted from aquatic organisms. In this review study, the cytotoxicity (IC50) and antibacterial effect of various extracts from marine organisms of the Persian Gulf are explored, compiled, and compared. Due to their easy accessibility, most of the studies are green, red, and brown algae.

Immunohematology Red Cell Serology Testing Reference Laboratory

Immunohematology reference laboratory (IRL) is defined as a fully equipped advanced laboratory that receives samples from various parts of the country for workup. This is a specialized center, where other centers experiencing difficulty in resolving immunohematological tests, refer samples for further workup and resolution. To complete the workup process, ABO RhD typing, antibody screening, identification (ID), antigen phenotyping, and direct antiglobulin tests are performed. In our retrospective observational study 528 cases, worked up from October 2019 to March 2022 were included. The prevalence of alloimmunization found in this evaluation was 68.1%. Among the different alloantibodies, anti-D was most common followed by anti-E and anti-M. In our study, most of the autoantibodies were of Immunoglobulin G (IgG) class (79.31%). Out of the 528 samples, ABO discrepancy was found in 48 samples (9%). Of these, none belonged to Group I or Group III discrepancy types. Group II discrepancies were noted in 28 cases (58.3%) and Group IV discrepancies were found in 20 cases (41.6%). Our study clearly indicates that there is an important role of IRL which is not only limited to ID of alloantibodies or resolution of ABO discrepancies but also supports all the hospitals and transfusion centers in the region by providing phenotype-matched or compatible units and advice for safe transfusion practices.

The Effect of Chemistry Experiment Classes Utilizing Advanced Laboratory Equipment at Science High Schools on the Development of Affective Characteristics in Science of Ordinary High School Students Hoping for Careers in Science and Engineering

The Effect of Chemistry Experiment Classes Utilizing Advanced Laboratory Equipment at Science High Schools on the Development of Affective Characteristics in Science of Ordinary High School Students Hoping for Careers in Science and Engineering

DYNAMIC SUBSTANCE RESEARCH IN DOMESTIC AND IMPORTED BLACK TEA SOLD IN TURKEY

Tea is a popular product known worldwide with health benefits for consumers. For centuries, it has been considered a safe and healthy beverage. Although the tea plant has many beneficial effects on human health, the chemicals that can be found in the tea plant can cause negative effects on health. Recently, the use of dyes in teas comes to the fore among imitations or adulterations made in foods recently. These substances pose a health risk.The purpose of this study; sold in the provinced in Turkey's Southeast Anatolia and Eastern Anatolia regions and to assess the presence of dye in the domestic and imported tea. In the study (Mardin; 7, Sirnak, 3, Van, 15, Diyarbakir, 13, Siirt, 9, Batman; 4, Gaziantep, 14, Kilis, 4 and Sanliurfa; 10) Iran, Sri Lanka, India and originating in Turkey A total of 79 samples were taken from the black teas and a wool yarn dyeing analysis with ( GMMAY S: 94-107 ) method was performed to look for dyes. The analyzes were carried out in an advanced private laboratory with European Union accreditation. According to the analysis results, no dye was detected in any of the tea samples. According to these results, it was concluded that no dyestuff is used in the harvesting, processing, drying and packaging stages of local and imported teas sold in the Southeastern Anatolia and Eastern Anatolia regions. Turkey determined to make the presence of dyes in general in the domestic and imported tea in other regions such analysis is required.

Leishmania infantum infection does not affect the main composition of the intestinal microbiome of the Syrian hamster

BackgroundVisceral leishmaniasis (VL) is the most severe form of all leishmanial infections and is caused by infection with protozoa of Leishmania donovani and Leishmania infantum. This parasitic disease occurs in over 80 countries and its geographic distribution is on the rise. Although the interaction between the intestinal microbiome and the immune response has been established in several pathologies, it has not been widely studied in leishmaniasis. The Syrian hamster is the most advanced laboratory model for developing vaccines and new drugs against VL. In the study reported here, we explored the relationship between the intestinal microbiome and infection with L. infantum in this surrogate host.MethodsMale Syrian hamsters (120–140 g) were inoculated with 108 promastigotes of a canine-derived L. infantum strain or left as uninfected control animals. Infection was maintained for 19 weeks (endpoint) and monitored by an immunoglobulin G (IgG) enyzme-linked immunosorbent assay throughout the experiment. Individual faecal samples, obtained at weeks 16, 18 and 19 post-inoculation, were analysed to determine the 16S metagenomic composition (the operational taxonomic units [OTUs] of the intestinal microbiome and the comparison between groups were FDR (false discovery rate)-adjusted).ResultsLeishmania infantum infection elicited moderate clinical signs and lesions and a steady increase in specific anti-Leishmania serum IgG. The predominant phyla (Firmicutes + Bacteriodetes: > 90%), families (Muribaculaceae + Lachnospiraceae + Ruminococcaceae: 70–80%) and genera found in the uninfected hamsters showed no significant variations throughout the experiment. Leishmania infantum infection provoked a slightly higher—albeit non-significant—value for the Firmicutes/Bacteriodetes ratio but no notable differences were found in the relative abundance or diversity of phyla and families. The microbiome of the infected hamsters was enriched in CAG-352, whereas Lachnospiraceae UCG-004, the [Eubacterium] ventriosum group and Allobaculum were less abundant.ConclusionsThe lack of extensive significant differences between hamsters infected and uninfected with L. infantum in the higher taxa (phyla, families) and the scarce variation found, which was restricted to genera with a low relative abundance, suggest that there is no clear VL infection-intestinal microbiome axis in hamsters. Further studies are needed (chronic infections, co-abundance analyses, intestinal sampling, functional analysis) to confirm these findings and to determine more precisely the possible relationship between microbiome composition and VL infection.Graphical

Determination of cyclic soil parameters for offshore foundation design from an existing data base

Determination of the soil parameters in the foundation design analyses for offshore and nearshore platforms subjected to cyclic loading from wind and waves requires extensive advanced laboratory testing. The amount of such testing can be reduced by drawing on the experience that has been gained during the design of offshore structures in the past. It is outlined how an existing data base can be used to estimate the soil parameters needed in the foundation design analyses based on conventional parameters, like undrained static shear strength, plasticity index and overconsolidation ratio for clays, and relative density and/or water content, fines content and overconsolidation ratio for sand and silt. The estimated soil parameters can be used in feasibility analyses before site-specific parameters are available and to reduce the amount of site-specific advanced laboratory testing in the final design phase. The application of the data base is demonstrated by examples for clay and for sand with different fines content.

A simple diagnostic scoring system for COVID-19 screening

Background: The COVID‐19 pandemic has prompted the world to make various efforts to control its spread by finding ways to diagnose COVID‐19 quickly and accurately. Early identification of COVID‐19 infection is essential, especially in hospitals with limited resources. We aimed to generate two scores based upon clinical and laboratory findings in patients screen for COVID-19 infection.
 Methodology: This study used a retrospective cohort design that involved 705 adults (≥ 18 y old) admitted in Dr. Sardjito Hospital and Dr. S. Hardjolukito Hospital. The patients' data collected included demographic characteristics, anamnesis on signs and symptoms, history of contact with COVID-19 patients, history of staying or visiting an endemic area, comorbidities, and laboratory and radiologic indicators. All variables with a P < 0.25 on the bivariate test were included in a univariable logistic regression. If the P < 0.05, the variable was included in the multivariable logistic regression with a P < 0.05 considered significant. Receiver Operating Characteristic (ROC) producing an area under the curve (AUC) with 95% confidence intervals (CIs) was used to assess discrimination power.
 Results: Two scores were generated; score in Model 1 consisted of clinical signs, basic laboratory indicators, and chest X-ray, and in Model 2 consisted of clinical signs, chest X-ray, basic and advanced laboratory indicators, including C-reactive protein (CRP), lactate dehydrogenase (LDH), albumin, and D-dimer. The ROC score of Model 1 was 0.801 (0.764−0. 838), which is considered good discrimination, and of Model 2 had excellent discrimination with a ROC of 0.858 (0.826−0. 891); the differences in the ROC of the two models was statistically significant (P = 0.03). The score of Model 1 more than 5 had 85% sensitivity and 61% specificity of positive COVID-19. A score of Model 2 more than 4 had 83% sensitivity and 72% specificity for diagnosing positive COVID-19.
 Conclusions: A simple score consisting of clinical symptoms and signs, and simple laboratory indicators can be used to screen for COVID-19 infection.
 Abbreviations: ARDS: Acute respiratory distress syndrome; CRP: C-reactive protein; MLR: monocyte-to-lymphocyte ratio; NLR: Neutrophil-to-lymphocyte ratio; RT-PCR: Reverse Transcription-Polymerase Chain Reaction;
 Key words: COVID-19; Screening System; Clinical Symptoms; Laboratory Indicators
 Citation: Widyastuti Y, Sari D, Kurniawaty J, Widodo U, Fitriani RW C, Jufan AY, Sutaendy K, Jaya P, Ulfa D. A simple diagnostic scoring system for COVID-19 screening. Anaesth. pain intensive care 2022;26(6):784-791.
 DOI: 10.35975/apic.v26i6.2076

A simple electronic circuit demonstrating Hopf bifurcation for an advanced undergraduate laboratory

A nonlinear electronic circuit comprising of three nodes with a feedback loop is analyzed. The system has two stable states, a uniform state and a sinusoidal oscillating state, and it transitions from one to another by means of a Hopf bifurcation. The stability of this system is analyzed with nonlinear equations derived from a repressilator-like transistor circuit. The apparatus is simple and inexpensive, and the experiment demonstrates aspects of nonlinear dynamical systems in an advanced undergraduate laboratory setting.

Power hardware-in-the-loop testbeds for advances laboratory testing of smart grid applications

Abstract This paper assesses practical aspects related to advanced laboratory testing of smart grid applications with Power-Hardware-in-the-Loop (PHIL) approach. Particularly, the general features together with a set of extended use-cases for PHIL testing are introduced. An existing laboratory at TU Dortmund University is presented and considered as a reference for describing the architecture and the principal components of typical advanced laboratory testing infrastructures based on PHIL approach. A number of exemplary testbeds are provided to show the potentially applications of advanced PHIL testing for low-voltage distribution grids.

Large diameter laterally loaded piles in sand: Numerical evaluation of soil stress paths and relevance of laboratory soil element testing

This paper uses 3D numerical analyses to investigate the stress path experienced by soil elements around large diameter piles in sand subjected to monotonic drained lateral loading. Inspection of the loading-induced stresses in the soil revealed the multiaxial nature of these stress paths, which are characterised by rotation of one or more principal stress axes. Based on the outcome of the finite element analyses, typical stress paths for different soil elements around the piles are extracted. Such stress paths are then evaluated against those enabled by conventional and advanced laboratory soil element testing. It is found that a combination of tests in the Hollow Cylinder Torsional Apparatus (HCTA) can reproduce most features of the numerically identified stress paths for soil elements around the pile. Unavoidable limitations in laboratory testing are discussed as well as the major challenge in replicating the loading direction with respect to the material axes. Some guidance for the experimental implementation of these stress paths in the HCTA are provided as well as a discussion on the use of conventional experimental equipment, such as the conventional triaxial or simple shear apparatus.