Test Program Design Research Articles

Experimental parametric study of perforated steel plate fuses for mass timber seismic force resisting systems

The lack of practical connections with reliable desired energy dissipation capacity as the main components of a seismic force resisting system (SFRS) is a major obstacle in using mass timber in tall buildings located in seismically active regions. A common method to dissipate seismic energy in timber structures is through the yielding of steel material found in the mechanical connections. Under the induced seismic motions, these dissipative connections are intended to yield while the rest of the structure remains intact with minimum damage. In this research, the focus is on the use of perforated steel plate as a dissipating energy device and a seismic fuse. Previous tests have demonstrated the potential use of perforated steel plates as seismic fuses in mass timber SFRS and confirmed their scalability and predictability. Despite promising results under monotonic loading, their behavior under cyclic loading can be improved. This paper presents an experimental parametric study investigating the effects of the number of rows, shape, and size of perforations, the steel plate thickness, and the steel link size on the mechanical performance of the perforated plates. The obtained hysteresis responses and envelope curves are compared. It is found that the ellipse and stagger patterns possess the largest ultimate displacement and stiffness, respectively. In addition, no significant enhancement in the ultimate deformation was observed in the cyclic response of the fuse, beyond three rows of perforations. Within the range of the configurations considered, the reduced ultimate deformation under cyclic loading remains a technical challenge that needs to be addressed if this type of seismic fuse is to be installed in SFRS. The results will assist with the design of future test programs on full-size mass timber connections consisting of such fuses.

Fatigue Factor Assessment and Life Prediction of Concrete Based on Bayesian Regularized BP Neural Network.

Concrete tensile properties usually govern the fatigue cracking of structural components such as bridge decks under repetitive loading. A fatigue life reliability analysis of commonly used ordinary cement concrete is desirable. As fatigue is affected by many interlinked factors whose effect is nonlinear, a unanimous consensus on the quantitative measurement of these factors has not yet been achieved. Benefiting from its unique self-learning ability and strong generalization capability, the Bayesian regularized backpropagation neural network (BR-BPNN) was proposed to predict concrete behavior in tensile fatigue. A total of 432 effective data points were collected from the literature, and an optimal model was determined with various combinations of network parameters. The average relative impact value (ARIV) was constructed to evaluate the correlation between fatigue life and its influencing parameters (maximum stress level Smax, stress ratio R, static strength f, failure probability P). ARIV results were compared with other factor assessment methods (weight equation and multiple linear regression analyses). Using BR-BPNN, S-N curves were obtained for the combinations of R = 0.1, 0.2, 0.5; f = 5, 6, 7 MPa; P = 5%, 50%, 95%. The tensile fatigue results under different testing conditions were finally compared for compatibility. It was concluded that Smax had the most significant negative effect on fatigue life; and the degree of influence of R, P, and f, which positively correlated with fatigue life, decreased successively. ARIV was confirmed as a feasible way to analyze the importance of parameters and could be recommended for future applications. It was found that the predicted logarithmic fatigue life agreed well with the test results and conventional data fitting curves, indicating the reliability of the BR-BPNN model in predicting concrete tensile fatigue behavior. These probabilistic fatigue curves could provide insights into fatigue test program design and fatigue evaluation. Since the overall correlation coefficient between the prediction and experimental results reached 0.99, the experimental results of plain concrete under flexural tension, axial tension, and splitting tension could be combined in future analyses. Besides utilizing the valuable fatigue test data available in the literature, this work provided evidence of the successful application of BR-BPNN on concrete fatigue prediction. Although a more accurate and comprehensive method was derived in the current study, caution should still be exercised when utilizing this method.

Considering social inequalities in health in large-scale testing for COVID-19 in Montr\xe9al: a qualitative case study

BackgroundEvidence continues to demonstrate that certain marginalised populations are disproportionately affected by COVID-19. While many studies document the impacts of COVID-19 on social inequalities in health, none has examined how public health responses to the pandemic have unfolded to address these inequities in Canada. The purpose of our study was to assess how social inequalities in health were considered in the design and planning of large-scale COVID-19 testing programs in Montréal (Québec, Canada).MethodsPart of the multicountry study HoSPiCOVID, this article reports on a qualitative case study of large-scale testing for COVID-19 in Montréal. We conducted semi-structured interviews with 19 stakeholders involved in planning large-scale testing or working with vulnerable populations during the pandemic. We developed interview guides and a codebook using existing literature on policy design and planning, and analysed data deductively and inductively using thematic analysis in NVivo.ResultsOur findings suggest that large-scale COVID-19 testing in Montréal did not initially consider social inequalities in health in its design and planning phases. Considering the sense of urgency brought by the pandemic, participants noted the challenges linked to the uptake of an intersectoral approach and of a unified vision of social inequalities in health. However, adaptations were gradually made to large-scale testing to improve its accessibility, acceptability, and availability. Actors from the community sector, among others, played an important role in supporting the health sector to address the needs of specific subgroups of the population.ConclusionsThese findings contribute to the reflections on the lessons learned from COVID-19, highlighting that public health programs must tackle structural barriers to accessing healthcare services during health crises. This will be necessary to ensure that pandemic preparedness and response, including large-scale testing, do not further increase social inequalities in health.

Criteria for hydrogen-assisted crack initiation in Ni-based superalloy 718

The tensile mechanical properties of a Ni-based superalloy 718 uniformly precharged with ≈ 90 mass ppm hydrogen were investigated under a wide range of temperatures to shed light on the long-standing uncertainties surrounding the H-related embrittlement mechanisms of the material. The detrimental effect of H on ductility was found to be substantial in the near-ambient to high-temperature range, up to 300 °C, stemming from H-assisted microcrack initiations along annealing twin boundaries (ATBs) and crystallographic slip planes (SPs). Dynamic H-dislocation interaction, which has been thought to be a prerequisite for the onset of embrittlement, was found to be unimportant, as demonstrated by employing supplemental tests that incorporated prestraining and intermediate temperature changes. By combining the insights gained from the successfully designed test program, a new model for the nucleation process of H-induced fracturing was established.

Promoting Student Engagement during Large-Scale Testing

For test scores to be used to appropriately inform decision-making, and for the associated academic practice opportunities afforded during testing to benefit students, it is critical that students put forth sufficient effort and engagement during testing sessions. Existing research highlights that a substantial proportion of students may disengage during large-scale testing, and that this can be due to anxiety, difficulties sustaining attention, and/or low motivation. These reasons may vary by individual student and by the magnitude of test stakes attached to test scores. The universal design aspect of multiple means of engagement is described as a framework to inform the development and application of test engagement strategies for improving student test engagement. Various associated strategies that could be applied to improve student test engagement are described and situated as part of a multi-tiered approach. In addition, considerations for promoting student test engagement in the future by embedding targeted features within test program design are highlighted.

Parametric study and speciation analysis of rare earth precipitation using oxalic acid in a chloride solution system

Oxalic acid precipitation is a common step in the purification of rare earth elements (REE) from a concentrated pregnant leach solution (PLS). However, the presence of contaminants such as Al, Fe, and Ca in given amounts decreases the REE precipitation efficiency and product purity while also increasing the amount of oxalic acid needed to maximize recovery. As such, a statistically designed test program was performed to identify the optimal conditions necessary for a relatively low REE content PLS containing elevated concentrations of contaminant ions. The performance objective was maximization of REE precipitation efficiency while minimizing the oxalic acid dosage. A central composite design was utilized to quantify performance impacts and identify the ultimate set of parameter values for oxalic acid dosage, Fe(III) contamination concentration, solution pH, and reaction temperature. The resultant model suggested that oxalic acid dosage and reaction pH are the most significant factors for the REE precipitation efficiency, followed by the interaction of oxalic dosage and Fe concentration. Test results indicate that increasing the oxalic acid concentration from 0 g/L to 80 g/L improved the REE precipitation efficiency from approximately 4.2% to 95.0%. Furthermore, raising the solution pH from 0.5 to 2.5 considerably enhanced the precipitation efficiency from 0.0% to 98.9%. A solution temperature elevation decreased REE recovery, which indicated an exothermic reaction between REEs and oxalate anions. Finally, a high level of Fe contamination adversely impacted REE precipitation efficiency. To further the understanding of the REE-oxalate system, a fundamental solution chemistry study was performed using the equilibrium constants of the reactions. The study resulted in the development of oxalate speciation diagrams and provided an analysis of the REE precipitation characteristics at various oxalate anion concentrations and Fe(III) contamination levels using MINTEQ software. The dominant Fe(III) species in the solution system were found to be Fe-(C2O4)33-, Fe-(C2O4)2-, and Fe-(C2O4)+, which consume the majority of the oxalate anions. The simulated model was found to be in agreement with the experimental findings and helped to explain the adverse impact of increased iron concentrations on REE precipitation efficiency.

Considering Social Inequalities in Health in Large-Scale Testing for Covid-19 in Montreal: A Qualitative Case Study

Evidence shows that COVID-19 is exacerbating social inequalities in health (SIH). The aim of this qualitative study was to assess how SIH were considered in the design of large-scale COVID-19 testing programs in Montreal (Quebec, Canada). We conducted semi-structured interviews with 19 stakeholders involved in planning large-scale testing or working with vulnerable populations during the pandemic. We developed interview guides and a codebook using literature on policy design and planning, and analysed data deductively and inductively using thematic analysis in NVivo. Findings suggest that large-scale COVID-19 testing in Montreal did not initially consider SIH in their planning phases. However, adaptations were made over time to improve the accessibility, acceptability, and availability of testing services. Actors from the community sector played an important role to ensure that public health interventions considered SIH. These findings contribute to the reflections on the lessons learned from COVID-19, highlighting that public health programmes must address structural barriers to accessing healthcare services through multisectoral collaboration. This will be necessary to ensure that future health crises do not further increase SIH.

Dig It, Design It: A new simulation tool for the design of optimal subsurface testing programs

This paper presents a new simulation tool, Dig It, Design It, which allows the archaeologist to easily design an optimal subsurface sampling program for the detection of buried artefacts. The design of such a program rests upon the relationship between the sampling methodology and the characteristics of the artefact concentrations under study, principally their size, density and density distribution. While the need to consider this relationship has been previously established, a model which automatically performs these calculations had not yet been designed. Dig It, Design It is the first model to be presented which considers artefact site properties and detection probabilities to produce an optimal sampling strategy for the archaeologist, and to provide the detection probabilities for artefact sites with different properties. The model is available online, is very easy to use, and no mathematical knowledge is required. Dig It, Design It thus has the potential to dramatically increase the use of statistically defensible sampling programs within the archaeological community.

Design of Real Time Monitoring System for Dangerous Goods Transportation Based on DSP

To solve the hazardous goods transportation equipment state real-time monitoring and control system with TMS320F2812 of TI company as the core, through the shaping of the sensor into the alcohol gas signal, filtering, amplification, a / D conversion, A / D conversion using F2812 comes with 12 bit A / D converter, continuous sampling signal monitoring gas concentration change and through the acquisition of temperature and humidity signal, the gas concentration data were temperature and humidity compensation, accurate measurement, calibration gas data can be secondary sound and light alarm, and the MAX232 and PC data transfer, at any time to check and call history. Good monitoring and control to make the system more stable. System mainly includes sensor for gas detection, temperature detection pass, humidity sensor, signal conversion and processing unit, A / D conversion circuit, sound and light alarm unit, RS232 communication module, the battery monitoring unit, a gas pump control unit. DSP main program using modular programming, completed the DSP initialization of the main program module, real-time communication with the PC module and system function module test program design. Laboratory research on gas monitoring and control system scheme is designed in this paper for tankers physical model. and on this basis, focusing on the completion of the core part of the control system in the control card design and implementation. This system can realize the monitoring of the whole process of leakage of hazardous goods transport equipment, once dangerous goods transport vehicles of hazardous chemicals spill occurred, the system can real-time detection to the leakage and alarm, the modern crisis of goods logistics provides a security solution.

Process development testing for comminution circuit design

Metallurgical process development in greenfield projects must define the comminution flowsheet and establish the equipment sizes that are required to deliver the project design criteria. These are critical steps that heavily influence the financial performance of the project, requiring a detailed understanding of the ore properties of the project resources and the best practice methods to size comminution machines. This paper reviews current practices for determining the ore characteristics relevant to comminution circuit design. Particular attention is given to the design of sampling and testing programs, and the methods commonly applied to size crushers and mills for conventional size reduction applications in mineral processing.

Experimental investigation of pneumatic tire performance on ice: Part 1 – Indoor study

Currently, the probability of accident occurrence is much higher when driving on icy roads than on asphalt. Since the tire is the only element of the vehicle that contacts the icy road, it is crucial to thoroughly comprehend the friction mechanism at the tire–ice interface for improved tires and safety systems for icy roads. This study investigates the available friction levels at the tire–ice interface by varying operational parameters through the indoor testing program conducted at the Advanced Vehicle Dynamics Laboratory, Virginia Tech (in part I) and the outdoor testing program conducted at the Keweenaw Research Center (in part II). This two-part article presents the design of experiment, the indoor and outdoor test programs, and friction–slip ratio curves obtained from both test programs for different conditions. The effects of operational parameters and their inter-dependency for the entire slip ratio range during operation on ice is explained, as studied from the two test programs. This article (part I) details the indoor test method consisting of the ice creation procedure, pre-test procedures, the test procedure and analysis of the obtained friction–slip ratio curves. This experimental investigation performs the necessary groundwork and builds a strong foundation towards making driving on ice safe.

Experiment on Poisson's Ratio Determination about Corn Kernel

Poisson's ratio is one of the important physical parameters in the finite element calculation model of corn kernel. In this study, through the preparation of the test material and test program design, with the loading speed of the testing machine was 2mm/min, through applied different loading (30N, 90N, 120N and 150N) for Poisson's ratio determination about corn kernel with the experiment. The test results showed that the Poisson's ratio average value in 0.399-0.423 when the corn kernel moisture content was 13.2%, the greater loading was applied, and the smaller value in the fluctuation range of the Poisson's ratio was measured. When applied to the indenter loading of 150N, the corn kernel Poisson ratio fluctuation which was between the minimum and maximum value of 5.1%.

Research on the Relational Model of Corrosion Factors of Air Cooler on Atmospheric Tower

Corrosion perforation of air cooler on atmospheric tower in refinery is mainly caused by the outer wall pitting, and the leading factors which results in the air cooler failure are Cl-, PH , temperature and Na+. With orthogonal model design test program to the main factors, and through polarization curves experiments obtain the corresponding corrosion potential, corrosion rate, pitting potential. Analysis the change of Cl-, PH value, Temperature and Na+ to the air condenser corrosion influence. The results show that, Cl- concentration, Na+ concentration rise make air cooler on atmospheric tower happening corrosion easily; PH value rise make air cooler on atmospheric tower happening corrsion not easily, which has a protective effect to the passive film; Temperature rise make air cooler on atmospheric tower passivation membrane formation rate increase, and at the same time pitting corrosion is more easily to happen.

Design of Bending Deflection of Pipe Test Bed

For the production of high reliability, wide use range, low cost of the bending deflection of pipe test bed, the design of test program was optimized, the structural design. Design of experiment platform to meet the requirement of experiment, and has practical application value.

Model Test and Structural Behavior Analysis for Cable-Pylon Anchorage Zone of Cable-Stayed Bridge

In long-span cable-stay bridges, anchorage zone of cable-pylon is a key part to transfer cable force to pylon. Because of local concentrated force, irregular pylon section and complicated construction measures, a general mechanical analysis is unable to reflect actual stress distribution and working performance of anchorage zone. Based on Maling River Bridge in Guizhou province, China, clear finite element analysis and reliable full-scale model test for cable-pylon anchorage zone segment were carried out. Not only were design of model test and loading program introduced, but also test content and sensor arrangement were documented. In addition, details of finite element modeling were involved too, such as mesh generation, boundary condition and loading cases. Through comparison and analysis of stress increment and crack observation, the location where larger local tensile stress occurred was obtained. Corresponding anti-cracking load coefficient and safety coefficient of crack width were also presented. Parts of research findings have been used for the guidance of bridge construction.

HIV Testing: Principles and Practice

Testing is a potentially important intervention to slow the Human Immunodeficiency Virus (HIV) epidemic in Africa and elsewhere. Some countries in Africa have achieved high levels of testing but most have not. Cost, price, and questions of confidentiality have limited the expansion of testing. It looks possible, however, that there are choices as to the design of testing programs that would expand the number of people who could know their HIV status in ways that would be worthwhile.

Criterios para el Diseño de un Programa Piloto de Justicia Restaurativa Orientado a la Atención de Casos de Violencia Intrafamiliar en el Centro de Atención Integral a Víctimas de Violencia Intrafamiliar (CAVIF) de la Fiscalía General de la Nación en la Ciudad de Bogotá (Colombia)

This study sets the criteria to design a restorative justice test program for the attention of intra familiar violence cases at the Center of Integral Attention to Victims of Intra Familiar Violence (CAVIF) of the nation´s General Public Prosecutor. The exposed criteria is the result of a conceptual and methodological work applied to the collection, systematization and analysis of information collected through a descriptive exploratory research design. An intentional sample of participants was used, 20 users and 18 workers from the CAVIF, whom were deeply interviewed with previous definited categories. At this work, needs from the institutional scope, professional and from the users and workers are described, that allows to understand the needed conditions to propose general lines to ordinate a test program acording to the effective law at Colombia. Results allow to point the matter of developing qualification procedures in restorative justice with workers at charge of intrafamiliar violence conflicts at the CAVIF. As a final contribution, general criteria to the design and implementation of test programs and victims´ assistance programs is proposed.

Satisfiability-Based Automatic Test Program Generation and Design for Testability for Microprocessors

In this paper, we present a satisfiability (SAT)-based framework for automatically generating test programs that target gate-level stuck-at faults in microprocessors. The microarchitectural description of a processor is first translated into a unified register-transfer level (RTL) circuit description, called assignment decision diagram (ADD), for test analysis. Test generation involves extraction of justification/propagation paths in the unified circuit representation from an embedded module's input-output (I/O) ports to primary I/O ports, abstraction of RTL modules in the justification/propagation paths, and translation of these paths into Boolean clauses in conjunctive normal form (CNF). Additional clauses are added that capture precomputed test vectors/responses at the embedded module's I/O ports. An SAT solver is then invoked to find valid paths that justify the precomputed vectors to primary input ports and propagate the good/faulty responses to primary output ports. Since the ADD is derived directly from a microarchitectural description, the generated test sequences correspond to a test program. If a given SAT instance is not satisfiable, then Boolean implications (also known as the unsatisfiable segment) that are responsible for unsatisfiability are efficiently and accurately identified. We show that adding design for testability (DFT) elements is equivalent to modifying these clauses such that the unsatisfiable segment becomes satisfiable. Test generation at the RTL also imposes a large number of initial conditions that need to be satisfied for successful detection of targeted stuck-at faults. We demonstrate that application of the Boolean constraint propagation (BCP) engine in SAT solvers propagates these conditions leading to significant pruning of the sequential search space which in turn leads to a reduction in test generation time. Experimental results demonstrate an 11.1X speedup in test generation time for test generation at the RTL over a state-of-the-art gate-level sequential generator called MIX, at comparable fault coverages. An unsatisifiability-based DFT approach at the RTL improves this fault coverage to near 100% and incurs very low area overhead (3.1%). Unlike previous approaches that either generate a test program consisting of random instruction sequences or assume the existence of test program templates, the proposed approach constructs test programs in a deterministic fashion from the microarchitectural description of a processor

A Self Test Program Design Technique for Embedded DSP Cores

This paper describes a self test program design technique for embedded DSP cores. The method requires minimal knowledge of the core's internals and minimal insertion of external LFSR hardware, without scan insertions. The test program consists of a small set of instructions which operate iteratively on pseudorandom data generated by the LFSRs to fully test the DSP core components. The method uses instruction-based test metrics and a program template as a blueprint to generate the test program. The self test scheme has been successfully applied on an industrial-strength DSP core and the results compare favorably to other methods using ATPG and pseudorandom BIST.

HIV Counseling and Testing Program for Female Inmates: Analysis of Data From the Harris County Jail

Knowledge of demographics, risk factors, and infection rates is essential to the design of effective HIV counseling and testing programs for incarcerated women. This study analyzed data from 19,057...