Replicate Tests Research Articles

A model of cultural transmission by direct instruction: An exercise on replication and extension

This article replicates and extends an agent-based model of cultural transmission (Acerbi & Parisi, 2006). The original model uses artificial neural networks to inquire about the role of noise and selective cultural reproduction in imitation learning dynamics, both for static and dynamic environments. The replication tests the robustness of the original results, whereas the extension focuses on implementing an alternative type of learning: Direct instruction. The results of the extension suggest this type of learning could negatively affect the emergence of adaptive behavioral traits at the population level. Because of its reliance on explicit one-way communication and its reduced chance to question the traits transmitted, direct instruction might increase the time taken to find effective behavioral variants, in comparison with imitation. Yet, if the limit that defines inadequate behavior is chosen loosely enough, a sufficient amount of behavioral variations could be introduced in the behavioral pool so to ensure the development of highly adaptive variations. The text uses the implementation of direct instruction to discuss the role of extension in scientific endeavor, especially in interdisciplinary areas of research, such as the science of cultural evolution or agent-based computational social science.

Effect of biomass type, heating rate, and sample size on microwave-enhanced fast pyrolysis product yields and qualities

The products from fast pyrolysis of biomass are variable and highly dependent upon feedstock composition, particle size and geometry, and operating conditions such as heating rate, reaction temperature, and sweep gas composition and velocity. Microwave heating is internal to the biomass particles, thereby avoiding convective and conductive heat transfer limitations, which facilitates decoupling heat transfer effects from chemical reaction kinetics. This separation allows for elucidation of the primary effects of the original materials’ composition on product yields. To better understand the interconnectedness of biomass composition and fast pyrolysis (pyrolysis liquid oil yield in particular), a high throughput microwave-enhanced fast pyrolysis (MEFP) reactor was used to react 33 biomass samples with a minimum of three replicate tests each. The materials in this study included: woody feedstocks (with and without bark), agricultural residues, herbaceous energy crops, and blended feedstocks. The highest liquid yields were obtained from lumber (66.2 wt%) and tulip poplar (64.9 wt%), while the lowest yields were obtained from sorghum (47.8 wt%) and single-pass harvested corn stover (48.5 wt%). Liquid yields had an average standard deviation of 1.4 wt% (average 2.5% relative standard deviation). The MEFP achieved heating rates up to 200 °C/s, however, beyond 10 °C/s liquid oil plateaued with increasing heating rate. Multivariate regression of pyrolysis yields with over 20 feedstock properties, obtained through detailed compositional analysis, indicates that aggregated alkali and alkaline Earth metals (primarily K and Na, along with Ca and Mg) accounted for the most variability among liquid yields (R2 = 0.71). Addition of volatile matter as a second predictor variable achieved the greatest reduction of the model residuals to increase the coefficient of regression (R2) to 0.85. Liquid yield water fraction increased linearly with feedstock potassium and sodium content over a much wider range than previously observed. Pyrolysis oil acid content was found to increase with increasing volatile matter and decreasing potassium and sodium content.

Gene-Centric Analysis of Preeclampsia Identifies Maternal Association at PLEKHG1.

The genetic susceptibility to preeclampsia, a pregnancy-specific complication with significant maternal and fetal morbidity, has been poorly characterized. To identify maternal genes associated with preeclampsia risk, we assembled 498 cases and 1864 controls of European ancestry from preeclampsia case-control collections in 5 different US sites (with additional matched population controls), genotyped samples on a cardiovascular gene-centric array composed of variants from ≈2000 genes selected based on prior genetic studies of cardiovascular and metabolic diseases and performed case-control genetic association analysis on 27 429 variants passing quality control. In silico replication testing of 9 lead signals with P<10-4 was performed in independent European samples from the SOPHIA (Study of Pregnancy Hypertension in Iowa) and Inova cohorts (212 cases, 456 controls). Multiethnic assessment of lead signals was then performed in samples of black (26 cases, 136 controls), Hispanic (132 cases, 468 controls), and East Asian (9 cases, 80 controls) ancestry. Multiethnic meta-analysis (877 cases, 3004 controls) revealed a study-wide statistically significant association of the rs9478812 variant in the pleiotropic PLEKHG1 gene (odds ratio, 1.40 [1.23-1.60]; Pmeta=5.90×10-7). The rs9478812 effect was even stronger in the subset of European cases with known early-onset preeclampsia (236 cases diagnosed <37 weeks, 1864 controls; odds ratio, 1.59 [1.27-1.98]; P=4.01×10-5). PLEKHG1 variants have previously been implicated in genome-wide association studies of blood pressure, body weight, and neurological disorders. Although larger studies are required to further define maternal preeclampsia heritability, this study identifies a novel maternal risk locus for further investigation.

Experimental in-plane performance of insulated concrete and brick masonry wall panels retrofitted using polymer composites

Masonry infilled reinforced concrete frame buildings built prior to the introduction of modern seismic provisions have been observed to undergo damage in and around the masonry infill walls during most recent moderate to severe earthquakes. Fibre reinforced cementitious matrix (FRCM) is one of several retrofitting options available to limit such earthquake induced damage to infill walls. An experimental program was undertaken herein to experimentally investigate the effectiveness of FRCM as a strengthening solution for vintage (i.e. built between 1880 and 1930) un-reinforced brick masonry (URM) and insulated concrete masonry (IMU) infill walls. A total of 16 masonry assemblages were tested under in-plane diagonal load, of these 8 were constructed replicating vintage URM whereas the remainder were constructed using modern IMU. IMU is a preferred masonry type in hot and humid regions owing to its superior insulting capability. Different polymer fabrics (i.e., carbon, glass and basalt) were applied over both faces of test walls, with two replicate test walls receiving the same FRCM strengthening details. One test wall of each masonry type was tested as-built to serve as a control specimen for comparison. One wall of each masonry type received two layers of basalt FRCM. The investigated aspects included stress-strain behaviour, stiffness, and ductility. Shear strength increment observed due to single layer of FRCM application was 422-778% for vintage URM and 307-415% for modern IMU. FRCM also substantially increased the ductility capacity of the masonry assemblages.

Genetic Introgression from Glycine tomentella to Soybean to Increase Seed Yield

Soybean [Glycine max (L.) Merr.] breeding in the United States currently relies on a narrow genetic base. Glycine tomentella Hayata (2n = 78), native to Australia, is a perennial relative in the tertiary gene pool of soybean. No effort has been devoted to using this species to increase seed yield. The objectives of this research were (i) to identify high‐yielding lines derived from backcrosses between the soybean cultivar Dwight (2n = 40) and G. tomentella PI 441001 (2n = 78) and to compare their agronomic performance with that of the recurrent parent, and (ii) to determine associations between G. tomentella introgressions and agronomic traits. PI 441001 was crossed to Dwight and immature seed rescue was used to produce a sterile F1 plant. Amphidiploid plants (2n = 118) were produced by treating the F1 hybrid with colchicine. Amphidiploid plants were backcrossed to Dwight and a series of backcrosses were made to obtain lines with 2n = 40 chromosomes, which were self‐fertile and genetically stable. Preliminary yield testing was used to select 180 lines in maturity groups II, III, and IV that had yields greater than or less than that of the recurrent parent. Yield data collected in two replication tests at six to eight locations in 2013 and 2014 identified experimental lines in all three maturity groups that were higher yielding than the recurrent parent. All experimental and parental lines were genotyped, revealing an average of 1% G. tomentella introgression. Significant associations were detected between G. tomentella introgressions and time of flowering, height, lodging, and yield.

Simple Effective Conservative Treatment of Uncertainty From Sparse Samples of Random Variables and Functions

Abstract This paper examines the variability of predicted responses when multiple stress–strain curves (reflecting variability from replicate material tests) are propagated through a finite element model of a ductile steel can being slowly crushed. Over 140 response quantities of interest (QOIs) (including displacements, stresses, strains, and calculated measures of material damage) are tracked in the simulations. Each response quantity's behavior varies according to the particular stress–strain curves used for the materials in the model. We desire to estimate or bound response variation when only a few stress–strain curve samples are available from material testing. Propagation of just a few samples will usually result in significantly underestimated response uncertainty relative to propagation of a much larger population that adequately samples the presiding random-function source. A simple classical statistical method, tolerance intervals (TIs), is tested for effectively treating sparse stress–strain curve data. The method is found to perform well on the highly nonlinear input-to-output response mappings and non-normal response distributions in the can crush problem. The results and discussion in this paper support a proposition that the method will apply similarly well for other sparsely sampled random variable or function data, whether from experiments or models. The simple TI method is also demonstrated to be very economical.

Return to Play After Hip Arthroscopy: A Systematic Review and Meta-analysis

Background: The use of arthroscopic treatment for intra-articular hip pathology has demonstrated improved patient-reported outcomes (PROs) with a lower rate of complications, reoperation, and patient morbidity as compared with traditional methods. Although the use of this minimally invasive approach has increased in prevalence, no evidence-based return-to-play (RTP) criteria have been developed to ensure an athlete’s preparedness for sporting activities. Purpose: To determine if there exists sufficient evidence in the literature to support an RTP protocol and functional assessment after hip arthroscopy, as well as to assess the mean rate and duration of RTP. Study Design: Systematic review and meta-analysis. Methods: The search terms “hip arthroscopy,” “return to play,” and 10 related terms were searched in PubMed, Cochrane Library, Scopus, and Web of Science, yielding 263 articles. After screening, 22 articles were included. RTP timeline, rehabilitation protocols, and conditional criteria measures were assessed with previously established criteria. Pooled estimates were calculated for RTP rate and duration, and weighted mean scores were determined for PROs. Results: A total of 1296 patients with 1442 total hips were identified. Although 54.5% (12 of 22) of studies did not provide a guideline for RTP duration after hip arthroscopy, 36.4% (8 of 22) recommended a duration of 4 months, while 9.1% (2 of 22) recommended 3 months. The most frequently described postoperative rehabilitation protocols were weightbearing guidelines (15 studies) and passive motion exercises (9 studies). Only 2 studies satisfied the criteria for a sufficient RTP protocol, and 3 provided a specific replicable test for RTP. The mean RTP duration was 7.4 months (95% CI, 6.1-8.8 months), and the return rate was 84.6% (95% CI, 80.4%-88.8%; P = .008) at a mean ± SD follow-up of 25.8 ± 2.4 months. Mean modified Harris Hip Score (mHHS) improved from 63.1 to 84.1 postoperatively (+33.3%), while Non-arthritic Hip Score improved from 61.7 to 86.8 (+40.7%). A lower preoperative mHHS was significantly associated with a higher postoperative improvement (r = −0.95, P = .0003). Conclusion: Significant variability exists in RTP protocols among institutions owing to a lack of standardization. Despite a high overall rate of RTP and improvement in PROs after hip arthroscopy, the majority of rehabilitation protocols are not evidence based and rely on expert opinion. No validated functional test currently exists to assess RTP.

Multiplexed chemostat system for quantification of biodiversity and ecosystem functioning in anaerobic digestion

Continuous cultures in chemostats have proven their value in microbiology, microbial ecology, systems biology and bioprocess engineering, among others. In these systems, microbial growth and ecosystem performance can be quantified under stable and defined environmental conditions. This is essential when linking microbial diversity to ecosystem function. Here, a new system to test this link in anaerobic, methanogenic microbial communities is introduced. Rigorously replicated experiments or a suitable experimental design typically require operating several chemostats in parallel. However, this is labor intensive, especially when measuring biogas production. Commercial solutions for multiplying reactors performing continuous anaerobic digestion exist but are expensive and use comparably large reactor volumes, requiring the preparation of substantial amounts of media. Here, a flexible system of Lab-scale Automated and Multiplexed Anaerobic Chemostat system (LAMACs) with a working volume of 200 mL is introduced. Sterile feeding, biomass wasting and pressure monitoring are automated. One module containing six reactors fits the typical dimensions of a lab bench. Thanks to automation, time required for reactor operation and maintenance are reduced compared to traditional lab-scale systems. Several modules can be used together, and so far the parallel operation of 30 reactors was demonstrated. The chemostats are autoclavable. Parameters like reactor volume, flow rates and operating temperature can be freely set. The robustness of the system was tested in a two-month long experiment in which three inocula in four replicates, i.e., twelve continuous digesters were monitored. Statistically significant differences in the biogas production between inocula were observed. In anaerobic digestion, biogas production and consequently pressure development in a closed environment is a proxy for ecosystem performance. The precision of the pressure measurement is thus crucial. The measured maximum and minimum rates of gas production could be determined at the same precision. The LAMACs is a tool that enables us to put in practice the often-demanded need for replication and rigorous testing in microbial ecology as well as bioprocess engineering.

Water quality index assesment around industrial area in Kuantan, Pahang

This study was conducted to determine water quality parameters and measure the Water Quality Index (WQI) based on Interim National Water Quality Standards, Malaysia (INWQS) classification. The sampling was carried out on February 2017 which are Balok River (S1), Pengorak River (S2) and Karang River (S3). The physical and chemical parameters were temperature, DO, pH, TDS, turbidity, BOD, COD, TSS and AN. Results show that base on Malaysian WQI, and the water of S1, S2 and S3 were 70.737, 66.127 and 73.098 respectively. Two-way ANOVA with replication test (P < 0.05) shows that all water quality parameters had significant differences between the sampling stations. In conclusion, S1, S2 and S3 were categorized as a slightly polluted river (WQI) and were classified as Class III. Keywords: Gebeng industrial; water quality; Balok River; Pengorak River; Karang River

The Effect of Avocado to the Profile of Blood Urea Nitrogen (BUN) and Creatinine in Rats (Rattus norvegicus) Induced with Meloxicam

Incidence of drug overdose during treatment of acute disease consequently leads to serious renal damage. As supporting treatment, administration of herbal medicine and food dietary are frequently developed. This research aimed to prove how the administration of avocado juice could lower the BUN and creatinine level in white rats induced with toxic doses of meloxicam. Meloxicam is a non-steroidal anti-inflamatory drug (NSAID), which is effectively used as an anti-inflamatory, analgesic, and antipyretic. Twenty four (24) male Wistar rats were assigned to 4 groups of six rats each (n=6). 1 ml of CMC 1% was administered to Control Group I, 30 mg/kgBB meloxicam and 1 ml of CMC 1% to Control Grup II, 30 mg/kgBB meloxicam and avocado juice 5 g/kgBB/day to Treatment Group I, and 30 mg/kgBB meloxicam and avocado juice 10 g/kgBB/day to Treatment Group II. The study was conducted over 8 days, then the level of Blood Urea Nitrogen and creatinine of the white rats were examined on the 1st and 8th day. The results were analyzed by Anova Two Way With Replication, then followed by T-test (α = 0,05) if there were difference. The Anova Two Way With Replication test showed that the mean of the four groups either the levels of Blood Urea Nitrogen or creatinine was significantly decreased (p&lt;0,05). The decrease of BUN in the treatment group I was 27,17 27,17mg/dl and 17,83mg/dl while the decrease of creatinine level was 0,983mg/dl and 0,713mg/dl. The conclusion of this study was that avocado juice decreases level of Blood Urea Nitrogen and creatinine in white rats which exposed toxic doses of meloxicam.

Peer Victimization and Neurobiological Models: Building Toward Comprehensive Developmental Theories

The articles in this special issue represent progress toward a more comprehensive developmental model of peer victimization and neurobiology. In this commentary, we highlight features of each article that reveal nuances in such a developmental model as related to sex, form of peer victimization, developmental course and period, and neurobiological response system and stimulus. We also encourage further research with an emphasis on longitudinal studies that cross developmental periods and elucidate directions of causality and mechanisms of change, expanded attention to individual and environmental variables that may explain or contextualize effects, assessments of multiple neurobiological systems, and tests of replication, as well as innovation. We acknowledge the challenges of such research and thank the authors for their important contributions to the literature on peer victimization and neurobiology.

Analiza trenutnog stanja i ocena čvrstoće cevovoda na hidroelektrani Pirot

Hydro power plant Pirot, which was built in 1990, is an accumulation-derivative power plant, which consists of 2 above-ground vertical hydroelectric generating sets that contain Francis turbines with nominal power of 41,5 MW, manufactured in Czech Republic, a tunnel and a sunken pipeline with overall length of 2.030 m and diameter that ranges from 3.000 to 3.500 m. Pipes have been made of S275J2G3 steel. Pipe wall is 22 mm thick. Maximum pressure of 2.5 MPa occurs in front of the turbine cover. Geodetic measurements have been conducted permanently from the day the assembly was finished and pipeline was put into service, both when pipeline is empty and unloaded by hydrostatic pressure and when it is full. Analysis of obtained data regarding the movements along the pipeline route showed that from year 2003 there are significantly higher differences in movements comparing the situations when the pipeline is full and when it is empty in comparison with the previous period. This paper contains the analysis of current state and strength evaluation of the pipeline as a whole on the basis of results of non-destructive tests performed on the vital butt - welded joint in the curvature area at chainage 1+263 m (visual testing, magnetic particle testing, penetrant testing, ultrasonic testing, radiographic testing, metallographic replication testing).

Stability of a pyrimethamine suspension compounded from bulk powder.

Development of a stability-indicating high-performance liquid chromatography (HPLC) method for pyrimethamine analysis, with subsequent application of that method to assess the 90-day stability of a pyrimethamine suspension compounded from bulk USP-grade pyrimethamine powder, is described. A stability-indicating method of HPLC with ultraviolet detection specific to pyrimethamine was developed according to pharmacopeial recommendations and validated. The method was applied to investigate the stability of a 2-mg/mL pyrimethamine suspension in a vehicle consisting of Ora-Plus and Ora-Sweet (Perrigo) over a period of 90 days. Three replicate test preparations were stored at room temperature or refrigerated at 4.3-5.2 °C, and samples were analyzed in duplicate immediately after preparation and on study days 1, 2, 4, 7, 10, 14, 21, 30, 48, 60, 75, and 90. The 2-mg/mL suspension of pyrimethamine in Ora-Plus and Ora-Sweet retained 90-110% of the labeled potency to 90 days at both temperature ranges. However, color changes in the samples stored at room temperature observed at day 60 indicated that a beyond-use date less than 90 days from the preparation date should be specified when the suspension is to be stored at room temperature. The study demonstrated that USP-grade pyrimethamine powder can be formulated as a 2-mg/mL suspension in a vehicle of Ora-Plus and Ora-Sweet and is stable when stored at room temperature and when refrigerated, in amber plastic bottles, for 48 and 90 days, respectively.

PP4.4 - Replicate Aptima VL testing detects residual viremia in most ART-treated adults

Author(s): Bakkour, S; Keating, SM; Deng, X; Stone, M; Worlock, A; Deeks, S; Bacchetti, P; Dimapasoc, M; Lau, J; Montalvo, L; Hauenstein, S; Richman, D; Busch, MP

Variants regulating ZBTB4 are associated with age-at-onset of Alzheimer's disease.

The identification of novel genetic modifiers of age-at-onset (AAO) of Alzheimer's disease (AD) could advance our understanding of AD and provide novel therapeutic targets. A previous genome scan for modifiers of AAO among families affected by early-onset AD caused by the PSEN2 N141I variant identified 2 loci with significant evidence for linkage: 1q23.3 and 17p13.2. Here, we describe the fine-mapping of these 2 linkage regions, and test for replication in 6 independent datasets. By fine-mapping these linkage signals in a single large family, we reduced the linkage regions to 11% their original size and nominated 54 candidate variants. Among the 11 variants associated with AAO of AD in a larger sample of Germans from Russia, the strongest evidence implicated promoter variants influencing NCSTN on 1q23.3 and ZBTB4 on 17p13.2. The association between ZBTB4 and AAO of AD was replicated by multiple variants in independent, trans-ethnic datasets. Our results show association between AAO of AD and both ZBTB4 and NCSTN. ZBTB4 is a transcriptional repressor that regulates the cell cycle, including the apoptotic response to amyloid beta, while NCSTN is part of the gamma secretase complex, known to influence amyloid beta production. These genes therefore suggest important roles for amyloid beta and cell cycle pathways in AAO of AD.

Admixture mapping in the Hispanic Community Health Study/Study of Latinos reveals regions of genetic associations with blood pressure traits.

Admixture mapping can be used to detect genetic association regions in admixed populations, such as Hispanics/Latinos, by estimating associations between local ancestry allele counts and the trait of interest. We performed admixture mapping of the blood pressure traits systolic and diastolic blood pressure (SBP, DBP), mean arterial pressure (MAP), and pulse pressure (PP), in a dataset of 12,116 participants from the Hispanic Community Health Study/Study of Latinos (HCHS/SOL). Hispanics/Latinos have three predominant ancestral populations (European, African, and Amerindian), for each of which we separately tested local ancestry intervals across the genome. We identified four regions that were significantly associated with a blood pressure trait at the genome-wide admixture mapping level. A 6p21.31 Amerindian ancestry association region has multiple known associations, but none explained the admixture mapping signal. We identified variants that completely explained this signal. One of these variants had p-values of 0.02 (MAP) and 0.04 (SBP) in replication testing in Pima Indians. A 11q13.4 Amerindian ancestry association region spans a variant that was previously reported (p-value = 0.001) in a targeted association study of Blood Pressure (BP) traits and variants in the vitamin D pathway. There was no replication evidence supporting an association in the identified 17q25.3 Amerindian ancestry association region. For a region on 6p12.3, associated with African ancestry, we did not identify any candidate variants driving the association. It may be driven by rare variants. Whole genome sequence data may be necessary to fine map these association signals, which may contribute to disparities in BP traits between diverse populations.

Targeted next-generation sequencing identified ADAMTS5 as novel genetic substrate in patients with bicuspid aortic valve.

Bicuspid Aortic Valve (BAV) is the most common congenital heart disease, affecting >1% of the general population. Up to date, three genes, NOTCH1, GATA5 and SMAD6, have been linked to the isolated form of BAV. However, potential genetic determinants remain largely unknown in most BAV patients. Targeted next-generation sequencing of 7 BAV candidate genes (NOTCH1, GATA5, SMAD6, NOS3, ADAMTS5, Alk2 and SMAD2) was performed in 32 BAV patients. Additional 35 BAV patients and 238 tricuspid aortic valve (TAV) patients, consisting of 107 patients from the transcatheter aortic valve implantation (TAVI) registry and 131 patients from the coronary artery disease (CAD) registry, were selected for further genotyping. We found 2 rare non-synonymous variants in 2/7 genes in 3 BAV patients: one was NOTCH1:c.4297G>A and the other one was ADMTS5:c.935C>A that shared by two patients. NOTCH1:c.4297G>A has not been reported previously. ADMTS5:c.935C>A was predicted to be pathogenic by all applied algorithms. Alignment of protein sequences from all available species revealed that ADMTS5:p.Arg312Leu, produced by ADMTS5:c.935C>A, is located in a highly conserved region. The minor allele frequency of ADMTS5:c.935C>A in BAV patients was significantly higher than the matched population in TAV group (0.015 vs. 0, P=0.048). Our results suggested that ADMTS5:c.935C>A are potentially associated with BAV. Further studies, such as large sample case-control replication test and functional research, are needed to explore the role of this rare variant in the development of BAV.

Variation in SWI/SNF Chromatin Remodeling Complex Proteins is Associated with Alcohol Dependence and Antisocial Behavior in Human Populations

Testing for direct gene or single nucleotide polymorphism replication of association across studies may not capture the true importance of a candidate locus; rather, we suggest that relevant replication across studies may be found at the level of a biological process. We previously observed that variation in 2 members of the switching defective/sucrose nonfermenting (SWI/SNF) chromatin remodeling complex is associated with alcohol dependence (AD) in the Irish Affected Sib Pair Study for Alcohol Dependence. Here, we tested for association with alcohol-related outcomes using a set of genes functioning in the SWI/SNF complex in 2 independent samples. We used a set-based analysis to examine the 29 genes of the SWI/SNF complex for evidence of association with (i) AD in the adult Collaborative Study on the Genetics of Alcoholism (COGA) case-control sample and (ii) antisocial behavior, hypothesized to be a genetically related developmental precursor, in a younger population sample (Spit for Science [S4S]). We found evidence for association of the SWI/SNF complex with AD in COGA (p=0.0435) and more general antisocial behavior in S4S (p=0.00026). The genes that contributed most strongly to the signal in COGA were SS18L1, SMARCD1, BRD7, BCL7B, SMARCB1, and BCL11A. In the S4S sample, ACTB, ARID2, BCL11A, BCL11B, BCL7B, BCL7C, DPF2, and DPF3 all contributed strongly to the signal. We detected associations between the SWI/SNF complex and AD in an adult population selected from treatment-seeking probands and antisocial behavior in an adolescent population sample. This provides strong support for a role for SWI/SNF in the development of alcohol-related problems.

A Study on Metallographic Microstructure of Steel Materials Subjected to Fire

In view of the fact that construction of modern buildings tends to use a high ratio of iron materials, this study aimed to obtain the ratio of components of steel’s microstructure under different test conditions by heating a A36 steel sheet commonly used in buildings, and applying metallographic replication testing. When the steel sheet was heated above 800°C and then rapidly cooled by water, the ratio of components of the structure were changed dramatically: components such as pearlite disappeared, ferrite was reduced from 90% to a low of 20%, bainite was increased to a maximum of 35%, and martensite was increased to a maximum of 45%. Since the substantial increase of martensite phase in this study led the microstructure of iron material to become thinned out and scattered, the ductility of such material was significantly reduced accordingly, thereby making the steel sheet easily broken. This study expected to provide the test findings of the mechanical behavior and metallographic structure of steel, after being heated to a high temperature and then naturally cooled, to other relevant units of construction engineering to serve as reference for their evaluation of non-destructive testing of steel structures.

Compact facility for testing steady and transient thermal performance of building walls

Energy efficiency retrofit of buildings represents a key effort in reducing EU energy demand by 20% by 2020. However, predictions tend to overestimate savings by large percentages. The shortfall in savings can be attributed to incorrect predictive techniques, comfort takeback along with other behavioural and workmanship variables. Common predictive techniques related to heat loss tend to be based on the U-value of the building envelope. This paper presents the design of a more straightforward and compact version of the traditional Hot-Box apparatus (measures U-value) which instead determines the thermal resistance of samples of building envelope. U-value includes the need to measure/predict the effective surface resistances. In situ surface resistances, which include radiation and convection, are difficult to predict and vary depending on climatic conditions, exposure levels, surface emissivities among many other influences. The design of the test facility eliminates the need to incorporate these surface behaviour variables. This paper details the replicable apparatus and test methodology. The results of testing a hollow block wall of typical construction using the rig is then presented. The determined R-value is found to be within 1% of calculated values and the thermal time constant also matches closely with the most accurate predictive estimates.