bluuebunny/crossref_metadata_2025 huggingface dataset:
Outcomes of total hip arthroplasty using dual mobility components in patients with a femoral neck fracture
Authors: You Daniel , Sepehri Aresh , Kooner Sahil , Krzyzaniak Halli , Johal Herman , Duffy Paul , Schneider Prism , Powell James
Published: June 2020

Aims

Dislocation is the most common indication for further surgery following total hip arthroplasty (THA) when undertaken in patients with a femoral neck fracture. This study aimed to assess the complication rates of THA with dual mobility components (THA-DMC) following a femoral neck fracture and to compare outcomes between THA-DMC, conventional THA, and hemiarthroplasty (HA).

Methods

We performed a systematic review of all English language articles on THA-DMC published between 2010 and 2019 in the MEDLINE, EMBASE, and Cochrane databases. After the application of rigorous inclusion and exclusion criteria, 23 studies dealing with patients who underwent treatment for a femoral neck fracture using THA-DMC were analyzed for the rate of dislocation. Secondary outcomes included reoperation, periprosthetic fracture, infection, mortality, and functional outcome. The review included 7,189 patients with a mean age of 77.8 years (66.4 to 87.6) and a mean follow-up of 30.9 months (9.0 to 68.0).

Results

THA-DMC was associated with a significantly lower dislocation rate compared with both THA (OR 0.26; 95% CI 0.08 to 0.79) and HA (odds ratio (OR) 0.27; 95% confidence interval (CI) 0.15 to 0.50). The rate of large articulations and of intraprosthetic dislocation was 1.5% (n = 105) and 0.04% (n = 3) respectively.

Conclusion

THA-DMC when used in patients with a femoral neck fracture is associated with a lower dislocation rate compared with conventional arthroplasty options. There was no increase in the rates of other complication when THA-DMC was used. Future cost analysis and prospective, comparative studies are required to assess the potential benefit of using THA-DMC in these patients. Cite this article: Bone Joint J 2020;102-B(7):811–821.
Extremes of body mass index have significant impact on complications, readmissions, and utilization of post-acute services after primary total hip arthroplasty
Authors: Tompkins Geoffrey , Neighorn Chris , Li Hsin-Fang , Fleming Kevin , Lorish Tom , Duwelius Paul , Sypher Katie
Published: June 2020

Aims

High body mass index (BMI) is associated with increased rates of complications in primary total hip arthroplasty (THA), but less is known about its impact on cost. The effects of low BMI on outcomes and cost are less understood. This study evaluated the relationship between BMI, inpatient costs, complications, readmissions, and utilization of post-acute services.

Methods

A retrospective database analysis of 40,913 primary THAs performed between January 2013 and December 2017 in 29 hospitals was conducted. Operating time, length of stay (LOS), complication rate, 30-day readmission rate, inpatient cost, and utilization of post-acute services were measured and compared in relation to patient BMI.

Results

Mean operating time increased with BMI and for BMI > 50 kg/m2 was approximately twice that of BMI 10 kg/m2 to 15 kg/m2. Mean inpatient cost did not vary significantly with BMI. Mean total reimbursement was lowest for the lowest BMI cohort and increased with BMI. Mean LOS was greatest at the extremes of BMI (4.0 days for BMI 10 kg/m2 to 15 kg/m2; 3.75 days for BMI > 50 kg/m2) and twice that of normal BMI. Mean complication rates were greatest in the lowest BMI cohort (16% for BMI 10 kg/m2 to 15 kg/m2) and five times the mean rate of complications in the normal BMI cohorts. Furthermore, 30-day readmissions were greatest in the highest BMI cohort (10% for BMI > 50 kg/m2) and five times the rate for normal BMI patients.

Conclusion

LOS, complications, and 30-day readmissions all increase at the extremes of BMI and appear to be greater than those of patients with normal BMI. The lowest BMI patients had the lowest payment for inpatient stay yet were at considerable risk for complications and readmission. Patients with extreme BMI should be counselled about their increased risk of complications for THA and nutritional status/obesity optimized preoperatively if possible. Cite this article: Bone Joint J 2020;102-B(7 Supple B):62–70.
Have newer bearing surfaces changed expectations regarding the longevity of total hip arthroplasty?
Authors: Engh, Jr. Charles A. , McAsey Craig J. , Cororaton Agnes D. , Ho Henry , Hopper, Jr. Robert H.
Published: June 2020

Aims

The purpose of this study is to examine six types of bearing surfaces implanted at a single institution over three decades to determine whether the reasons for revision vary among the groups and how long it takes to identify differences in survival.

Methods

We considered six cohorts that included a total of 1,707 primary hips done between 1982 and 2010. These included 223 conventional polyethylene sterilized with γ irradiation in air (CPE-GA), 114 conventional polyethylene sterilized with gas plasma (CPE-GP), 116 crosslinked polyethylene (XLPE), 1,083 metal-on-metal (MOM), 90 ceramic-on-ceramic (COC), and 81 surface arthroplasties (SAs). With the exception of the COC, all other groups used cobalt-chromium (CoCr) femoral heads. The mean follow-up was 10 (0.008 to 35) years. Descriptive statistics with revisions per 100 component years (re/100 yr) and survival analysis with revision for any reason as the endpoint were used to compare bearing surfaces.

Results

XLPE liners demonstrated a lower cumulative incidence of revision at 15 years compared to the CPE-GA and CPE-GP groups owing to the absence of wear-related revisions (4% for XLPE vs 18%, p = 0.02, and 15%, p = 0.003, respectively). Revisions for adverse local tissue reactions occurred exclusively among the MOM (0.8 re/100 year) and SA groups (0.1 re/100 year). The revision rate for instability was lower among hips with 36 mm and larger head sizes compared to smaller head sizes (0.2% vs 2%, p < 0.001).

Conclusion

The introduction of XLPE has eliminated wear-related revisions through 15-year follow-up compared to CPE-GP and CPE-GA. Dislocation incidence has been reduced with the introduction of larger diameter heads but remains a persistent concern. The potential for adverse local tissue reactions with MOM requires continued follow-up. Cite this article: Bone Joint J 2020;102-B(7 Supple B):105–111.
Modelling changes in modular taper micromechanics due to surgeon assembly technique in total hip arthroplasty
Authors: Gustafson Jonathan A. , Pourzal Robin , Levine Brett R. , Jacobs Joshua J. , Lundberg Hannah J.
Published: June 2020

Aims

The aim of this study was to develop a novel computational model for estimating head/stem taper mechanics during different simulated assembly conditions.

Methods

Finite element models of generic cobalt-chromium (CoCr) heads on a titanium stem taper were developed and driven using dynamic assembly loads collected from clinicians. To verify contact mechanics at the taper interface, comparisons of deformed microgroove characteristics (height and width of microgrooves) were made between model estimates with those measured from five retrieved implants. Additionally, these models were used to assess the role of assembly technique—one-hit versus three-hits—on the taper interlock mechanical behaviour.

Results

The model compared well to deformed microgrooves from the retrieved implants, predicting changes in microgroove height (mean 1.1 μm (0.2 to 1.3)) and width (mean 7.5 μm (1.0 to 18.5)) within the range of measured changes in height (mean 1.4 μm (0.4 to 2.3); p = 0.109) and width (mean 12.0 μm (1.5 to 25.4); p = 0.470). Consistent with benchtop studies, our model found that increasing assembly load magnitude led to increased taper engagement, contact pressure, and permanent deformation of the stem taper microgrooves. Interestingly, our model found assemblies using three hits at low loads (4 kN) led to decreased taper engagement, contact pressures and microgroove deformations throughout the stem taper compared with tapers assembled with one hit at the same magnitude.

Conclusion

These findings suggest additional assembly hits at low loads lead to inferior taper interlock strength compared with one firm hit, which may be influenced by loading rate or material strain hardening. These unique models can estimate microgroove deformations representative of real contact mechanics seen on retrievals, which will enable us to better understand how both surgeon assembly techniques and implant design affect taper interlock strength. Cite this article: Bone Joint J 2020;102-B(7 Supple B):33–40.
Validación del cuestionario de competencia digital para futuros maestros mediante ecuaciones estructurales
Authors: Cabero-Almenara Julio , Barroso-Osuna Julio , Gutiérrez-Castillo Juan Jesús , Palacios-Rodríguez Antonio
Published: June 2020

INTRODUCCION. La tecnología, como elemento necesario para el avance de la sociedad del Siglo XXI, ha asumido un papel fundamental en el entorno educativo. En esta línea, diferentes instituciones respaldan la importancia del desarrollo de la Competencia Digital para vivir, trabajar y aprender en la Sociedad del Conocimiento. Este trabajo analiza la fiabilidad y validez del “Cuestionario de Competencia Digital para Futuros Maestros”. Este instrumento está basado en los principales marcos de desarrollo de la competencia digital: estándares ISTE (Estados Unidos) e indicadores “DigComp” (Europa). Se concibe como una herramienta que permite al alumnado de magisterio una mejor comprensión de su nivel competencial, proporcionando una forma de autoevaluar sus fortalezas y necesidades o áreas de mejora de aprendizaje digital en distintas dimensiones: alfabetización tecnológica; comunicación y colaboración; búsqueda y tratamiento de la información; ciudadanía digital; creatividad e innovación. METODO. Para ello, se emplean técnicas de análisis factorial exploratorio (AFE) y análisis factorial confirmatorio (AFC) utilizando ecuaciones estructurales. En esta investigación participan 657 alumnos y alumnas del Grado en Educación Infantil y Grado en Educación Primaria de la Universidad de Sevilla.  RESULTADOS. Los resultados demuestran la fiabilidad y validez del cuestionario además de las posibilidades que ofrece la metodología de validación mediante ecuaciones estructurales. Así mismo, se subraya la importancia de usar instrumentos de evaluación competencial con fundamentos confiables que avalen su uso. DISCUSIÓN. Finalmente, se reclama una mayor oferta formativa y metodología educativa basada en competencias que esté garantizada por herramientas fiables y válidas.
What impact is dentistry having on the environment and how can dentistry lead the way?
Authors: Wilson Gavin J , Shah Sagar , Pugh Hannah
Published: June 2020

Integrating sustainable waste management and procurement into daily practice will encourage the dental profession to tackle environmental change.
An exploration of paediatric dentistry trainees’ attitudes towards academia
Authors: Timms Laura , Noble Fiona , Rogers Helen ,   on behalf of CONNECT (Child Oral health NatioNal rEsearch CollaboraTive)
Published: June 2020

To grow a clinical academic workforce, trainees have to receive the necessary funding, time and support to facilitate a balanced and rewarding career in academia.
Light transmission characteristic analyses of a laser screen in clear water based on the Monte Carlo method
Authors: Wang Fan , Ni Jinping , Tian Hui , Yang Tong
Published: June 2020

In order to optimize the design of underwater light screens, the transmission process of the light beam in water is analyzed with the Monte Carlo method. The trajectories and power attenuation of emitted photons, propagating in different types of water from the light source towards the receiver with different initial light powers and transmission distances, are simulated and calculated. The output power can then be obtained to calculate the transmission ratio quantitatively. According to the simulated data, by using the curving fitting method, the exact expression of transmission ratio is derived, which is in the same form as the Beer–Lambert–Bouguer law. Meanwhile, experiments are conducted in a light screen with a vertical line beam laser in clear water to verify the simulations. The experimental results are in agreement with the simulated results, and the differences between them are within

±
0.04

. The presented results give insight into the design of underwater laser screens.
QoT-aware performance evaluation of spectrally–spatially flexible optical networks over FM-MCFs
Authors: Arpanaei Farhad , Ardalani Nahid , Beyranvand Hamzeh , Shariati Behnam
Published: June 2020

In this paper, we study the quality of transmission (QoT) aware routing, modulation level, and resource assignment problem for transparent flexible optical networks over few-mode multi-core fibers. We consider two three-dimensional resource assignment (3DRA) algorithms, called liberal and conservative, that are compatible with fractional joint switching. The three resource dimensions are core, mode, and spectrum. Furthermore, we analyze two modulation-level selection (MLS) algorithms (one on-line and one off-line) and three path selection algorithms (favoring shortest path, best balanced load, or highest QoT). The results show that the liberal 3DRA algorithm has a similar blocking probability (BP) compared to conservative 3DRA. However, performance metrics such as computation time, optical signal-to-noise ratio (OSNR), and number of required lasers are all improved with conservative 3DRA. Moreover, the BP decreases and the average OSNR increases by applying the on-line MLS algorithm compared to the off-line algorithm. Finally, we use an on-line liberal algorithm with a path selection policy that favors load balancing to generate a solution with the lowest BP.
Characterization of flat-fielding systems for quantitative microscopy
Authors: Ibrahim Khalid A. , Mahecic Dora , Manley Suliana
Published: June 2020

Optical flat-fielding systems, such as field-mapping or integration-based beam shapers, are used to transform nonuniform illumination into uniform illumination. Thus, flat-fielding paves the way for imaging that is independent of position within a field of view and enables more quantitative analysis. Here, we characterize and compare three systems for homogenizing both widefield and multifocal illumination. Our analysis includes two refractive field-mapping beam shapers: PiShaper and TopShape, as well as one integration-based: Köhler integrator. The comparison is based on figures of merit including ISO-standard values, such as the plateau uniformity and edge steepness, transmission efficiency, stability of the beams along propagation and multifocal intensity, pitch, and point width. By characterizing and comparing existing beam shapers, we facilitate the choice of the appropriate flat-fielding solution and increase their accessibility for different applications.
Enhanced subwavelength coupling and nano-focusing with optical fiber-plasmonic hybrid probe: erratum
Authors: Minn Khant , Lee Ho Wai Howard , Zhang Zhenrong
Published: June 2020

In this erratum, the funding section of our paper [Opt. Express 27 38098 (2019)10.1364/OE.27.038098] has been updated.
Supplementation of a low-protein diet with tryptophan, threonine, and valine and its impact on growth performance, blood biochemical constituents, immune parameters, and carcass traits in broiler chickens
Authors: Abou-Elkhair Reham , Ahmed Hamada , Ketkat Sara , Selim Shaimaa
Published: June 2020

Aim: This study aimed to investigate the effects of protein reduction with supplementation of limiting amino acids (AA, tryptophan, threonine, and valine) on growth performance, blood biochemical, immunity parameters, and carcass traits in broiler chickens.

Materials and Methods: Three hundred one-day-old broiler chicks were randomly allotted into three treatment groups, with five replicates per treatment and 20 broiler chickens per replicate. The three experimental diets were formulated with different dietary crude protein (CP) %, (control [CON] and CON with 1% [CP-1%] or 2% [CP-2%] less CP units) during the starter, grower, and finisher phases. The CP of the experimental diets were 22, 21, and 20% for the starting period (day 1-14); 20, 19, and 18% CP for the growing period (day 15-28); and 18, 17, and 16% CP for the finishing period (day 29-35) in CON, CP-1%, and CP-2%, respectively. The low-CP diets (CP-1% and CP-2%) were supplemented with combined AA, threonine+tryptophan+valine, to meet the respective levels of the CON diet.

Results: The CP-2% group had greater (p<0.05; linear, p<0.05) final body weight and gain and better feed conversion ratio. The combined AA inclusion in the low-CP diet (CP-1% and CP-2%) increased (p<0.001; linear, p<0.001) carcass and breast meat yield as well as CP% of breast meat. The reduction of CP% with AA supplementation (CP-2%) decreased (p<0.05; linear, p<0.05) serum triglycerides, glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and alkaline phosphatase, while increased (p<0.01; linear, p<0.01) phagocytic activity and phagocytic index. The mRNA expression of splenic and cecal tonsil interleukin 4 and interferon gamma was upregulated (p<0.001; linear, p<0.001) in the low-CP diets supplemented with AA (CP-1% and CP-2%). Dietary supplementation with AA to low-protein diets improved (p<0.01; linear, p<0.01) the economic returns of broiler chickens.

Conclusion: A reduction of dietary CP and increased synthetic AA such as threonine, valine, and tryptophan should be considered to improve performance, health, and immunity in broiler chickens.
INTEGRATIVE TAXONOMY REVEALS CRYPTIC ROBIN LINEAGE IN THE GREATER SUNDA ISLANDS
Authors: Ng Elize Y. X. , Yue Arya Y. , Eaton James A. , Gwee Chyi Yin , Balen Bas Van , Rheindt Frank E.
Published: June 2020

Southeast Asian avifauna is under threat from both habitat loss and illegal poaching, yet the region’s rich biodiversity remains understudied. Here, we uncover cryptic species-level diversity in the Sunda Blue Robin (Myiomela diana), a songbird complex endemic to Javan (subspecies diana) and Sumatran (subspecies sumatrana) mountains. Taxonomic inquiry into these populations has previously been hampered by a lack of DNA material and the birds’ general scarcity, especially sumatrana which is only known from few localities. We demonstrate fundamental bioacoustic differences in courtship song paired with important distinctions in plumage saturation and tail length that combine to suggest species-level treatment for the two taxa. Treated separately, both taxa are independently threatened by illegal poaching and habitat loss, and demand conservation action. Our study highlights a case of underestimated avifaunal diversity that is in urgent need of revision in the face of imminent threats to species survival.
Faktor-faktor yang Memengaruhi Gambaran Elektroensefalografi Interiktal Anak yang Menderita Epilepsi
Authors: Permana Yanuar Nusca , Putranti Alifiani Hikmah , Setiawan Henry
Published: June 2020

Latar belakang. Elektroensefalografi (EEG) sebagai pemeriksaan penunjang sangat penting dalam mendiagnosis epilepsi bila didukung dengan data klinis. Hasil perekaman EEG dipengaruhi banyak faktor dan sekitar 50% epilepsi pada anak sering tidak menunjukkan aktivitas gelombang epileptiform. Dengan mengetahui faktor-faktor yang memengaruhi EEG, upaya awal untuk diagnosis dan tata laksana epilepsi pada anak dapat lebih efektif dan efisien.Tujuan. Untuk menganalisis faktor-faktor yang memengaruhi gambaran EEG interiktal pada anak epilepsi.Metode. Penelitian ini merupakan penelitian cross sectional pada anak epilepsi usia antara 1-18 tahun, yang melakukan pemeriksaan EEG selama Januari 2013 - Mei 2016 di CDC RSUP dr. Kariadi Semarang. Data dikumpulkan dengan wawancara terstruktur dan observasi langsung meliputi usia, jenis kelamin, jenis epilepsi, episode terakhir bangkitan epilepsi, dan penggunaan obat anti-epilepsi. Data dianalisis dengan chi square dan regresi logistik.Hasil. Hasil yang diperoleh bahwa variabel yang memengaruhi gambaran EEG interiktal adalah episode terakhir dari bangkitan epilepsi (OR=3,4; 95%CI 1,286-9,334) dan penggunaan obat anti-epilepsi (OR=52,8; 95%CI 15.962-174.795).Kesimpulan. Faktor-faktor yang memengaruhi gambaran EEG interiktal pada anak epilepsi adalah episode terakhir dari bangkitan epilepsi dan penggunaan obat anti-epilepsi.
Serviços Ecossistêmicos e a Agricultura Irrigada na Bacia do Ribeirão Rodeador, Distrito Federal
Authors: Lima Francielle do Monte , Roig Henrique Llacer , Neumann Marina Rolim Bilich , Lima Larissa Ane de Sousa , Souza André Luiz Farias de
Published: June 2020

Durante a crise hídrica enfrentada pelo Distrito Federal em 2016/2017, as discussões sobre conflitos pelo uso da água revelaram o déficit de informações do governo acerca das bacias utilizadas como mananciais para o abastecimento público de água. Este trabalho tem como objetivo avaliar a oferta do serviço ecossistêmico de provisão de alimentos, estimar o consumo de água pela agricultura irrigada e analisar o consumo de água em diferentes cenários considerando a substituição dos sistemas de irrigação na bacia do Ribeirão Rodeador, importante região produtora de olerícolas e frutas no Distrito Federal. Para quantificar a provisão de alimentos, foram utilizados dados de produtividade média das culturas agrícolas e área cultivada obtida pela confecção do mapa de uso e cobertura da bacia. A estimativa do consumo de água pela irrigação foi calculada com dados de área irrigada mapeada e consumo médio de água das culturas agrícolas em diferentes sistemas de irrigação. Foram produzidos três cenários considerando a substituição do sistema de irrigação por aspersão convencional por sistemas de irrigação localizada. O fornecimento de alimentos na bacia foi quantificado em 43.039 t/ano, utilizando 1.683 ha. O consumo de água na irrigação foi estimado em 891 L/s, sendo 1.470 ha irrigados. O aumento de 20% na adoção de sistemas de irrigação localizada proporciona uma economia de 9,3% no consumo de água. O aumento de 40% na irrigação localizada proporciona uma economia de 18,7% e o aumento de 60% na irrigação localizada proporciona uma economia de 28,1% no consumo de água na irrigação.
As lutas territoriais da memória contra o esquecimento
Authors: Sobreiro Filho José
Published: June 2020

A disputa territorial e a organização de movimentos socioterritoriais não são traços recentes da questão agrária brasileira. Pelo contrário, são elementos de um processo histórico-geográfico complexo que motivou um amplo conjunto de sujeitos, tanto à construção de experiências territoriais de ofensivas e resistências quanto a apropriação coletiva e o intercâmbio de experiências de luta. Parte expressiva desse processo resultou em múltiplas significações sobre a noção e conceito de território, no âmbito da lógica-racionalidade dos movimentos socioterritoriais, sendo que algumas expressões foram traduzidas em aspectos étnicos-raciais e culturais, recursos e bens comuns e o corpo. Nosso objetivo neste artigo é apresentar elementos para compreendermos não somente o caráter geográfico das lutas, mas também a indissociabilidade com o processo histórico de construção de resistências territoriais para que, aos poucos, os leitores possam compreender como o tema território compõe parte relevante dos conflitos no campo, desde os últimos cinco séculos de história do Brasil.
KONSTRUKSI MENDUKUNG DAN MENGKRITISI REALITAS PRABOWO SUBIANTO MENJADI MENTERI PERTAHANAN OLEH BEBERAPA MEDIA ONLINE
Authors: Sukarno Sukarno , Amurwani Pipiet Palestin
Published: June 2020

As the only political opponent in the 2019 presidential election, Prabowo Subianto (PS) became the public spotlight after the election and the inauguration of Jokowi as the President of the Republic of Indonesia. This study aims to reveal how the inauguration of PS as the defense minister in the Kabinet Indonesia Maju (the second period of Jokowi’s cabinet) is framed on Indonesian online media. The data were taken from online media texts that contain supports and criticism that surround this political reality. The data are analyzed descriptively and critically using Fairclough’s critical discouse analysis in order to see how language (vocabulary, modality, grammar, and the choice of media sources) is used in the construction of perspectives and attitudes towards the political news by online mass media. The findings of this research show that there are two types of framing constructed by the online media on PS: support and criticism. In terms of support, it is apparent through the claims that PS is the person that the country needs (President Jokowi), while in terms of criticism, PS is framed as the person who approaches Jokowi for the political position. In addition, the study also reveals that the different framing is highly influenced by the media owner’s alignment towards his own corporation, the market orientation, and the sosiopolitical situations in Indonesia.
REHABILITATION OF BRICK-WALL FAÇADES
Authors: Abrantes Vitor , Abrantes Nuno , Brandão Alves Fernando
Published: June 2020

This abstract seeks to analyze several existing cracking rehabilitation techniques on brick-wall façades. The examples concern to an upper-middle class housing complex, situated in Porto, Portugal. This housing complex holds 4 buildings (190 dwellings) and which construction is near 20 years old. The most significant anomalies that have been checked on this rehabilitation study were the cracks of the lintels over windows and on wall-corners of balconies. Both represent a severe anomaly on brick-wall façades that will have as consequence rain penetration and water infiltration. As result, one found that the horizontal lintel cracks occur as a consequence of conception mistakes due to a reduced armor support and to a poor covering. The lintel deformation will allow rain penetration through walls and water infiltrations into dwellings and provoke the severe deformation of the windows’ frames and, hereafter, problems with its opening. Beyond this the vertical wall-corner cracks are a consequence of a wrong procedure performed with the cut of the bricks. Regarding the horizontal lintel cracks, the method for its rehabilitation involves the demolition of the brick-wall façade and the execution of angle brackets before rebuilding the brick-wall. In respect to the vertical wall-corner cracks, the method for the rehabilitation consists on the stapling, using the application of stainless-steel helical pins to provide a strong mechanical solution when patch repairing the brick-wall (patch pin).
ALAMILLO BRIDGE: CONSTRUCTION SIMULATION MODELS IN EZSTROBE
Authors: Ioannou Photios G. , Likhitruangsilp Veerarsak
Published: June 2020

The Puente del Alamillo in Seville, Spain, designed by Santiago Calatrava, has a single pylon that rises at an angle away from the deck, and which together with the deck resembles a harp whose strings are the cable stays from the pylon to the deck. It is the only bridge of its kind in the world whose pylon is not back-anchored, and its deck and pylon balance at a single massive footing below the pylon. This design made construction of the bridge very risky because the unfinished bridge had to be kept in balance like a giant teeter-totter until it could rest at the secondary support away from the pylon. A total of three construction plans were investigated by the contractor with the first two rejected and the third used for construction. Previous research presented simulation models for these three plans in CYCLONE along with construction time estimates for the bridge deck and pylon. Unfortunately, the published simulation models had mistakes that led to incorrect statistical results and conclusions. This paper describes these mistakes and presents three simulation models in EZStrobe that produce appropriate statistics and conclusions. These models can be used as practical examples for the application of discrete-event simulation to construction.
BUNDLING: AN INNOVATION IN BRIDGE DELIVERY
Authors: D'Angelo Daniel , Minchin R. Edward , Tian Yifeng , An Bang
Published: June 2020

Public transportation agencies in the US have broken down the management of their bridge assets into four parts: preservation, preventive maintenance, rehabilitation, or replacement. As these agencies continue their battle to update and rehabilitate their civil infrastructure, bundling multiple bridge construction projects into a single contract can save money, human resources and time. State and local public agencies (LPAs) are beginning to employ this concept, but since practices and methods for bridge bundling are not yet standardized, the Federal Highway Administration has pursued tools and techniques to help these agencies successfully apply bridge bundling. A successful bridge bundling program focuses on a specific group (or bundle) of bridges that are slated for any of the four management areas, and navigates all the bridges in the bundle through the process from conception to completion. This is accomplished in the shortest time possible, with the support of the proper funding options and/or partnerships, Bridge bundling has demonstrated its ability to serve as an efficient and effective approach for sustaining and upgrading bridge assets through use of both federal and non-Federal funds. Use of the tool has led to cost savings and accelerated project delivery, and bridge bundling has proven itself valuable in all four of the major tactics currently employed to manage bridges.
THE EFFECTS OF POOR MANAGEMENT PRACTICES ON PROJECTS PERFORMANCE
Authors: Almutairi Saud , AlMunifi Abdullatif
Published: June 2020

The construction sector in the Kingdom of Saudi Arabia (KSA) faces issues related to a lack of project management toolbox. Over two-thirds of public construction projects in the KSA suffer from schedule overruns that may exceed twice the length of the contracted period. The current paper aims to investigate how clients’ management inefficiency plays a major role in delaying project execution and final product delivery, which may deviate from the contracted terms and expected standards. To achieve this objective, two case studies of serious schedule overruns were subjected to investigative research. Contractual documents, preliminary and modified project schedules, meetings minutes, and change orders were examined. Field visits and personal communications, as well as meetings and interviews with key players, were also conducted. The results of the analysis indicate that weak professional construction management coupled with a failure to introduce and implement solutions in a timely manner leads to serious schedule overruns. Delays impacted project life-cycle processes from initiation to project closing. The lessons learned from the many issues surrounding the two projects shed light on problem areas. These lessons also indicate the potential effectiveness of a pro-active management office, established early in the process, in preventing deficiencies in planning and managing projects.
ON THE MODULUS OF SUBGRADE REACTION FOR SHALLOW FOUNDATIONS ON HOMOGENOUS OR STRATIFIED MEDIUMS
Authors: Pantelidis Lysandros
Published: June 2020

As known, the modulus of subgrade reaction of soil, ks, is an essential parameter in designing flexible, shallow foundations based on the Winkler spring hypothesis, where, the foundation soil is modeled as a series of independent (elastic) springs having constant ks. In this paper the various methods for calculating the ks value are discussed, indicating that the more suitable one is Vesic’s ks=0.65[EB4/(EbIb)]1/12E/[B(1–v2)], where, E and v are the elastic constants of soil and Eb, Ib and B are the modulus of elasticity of the foundation material, the moment of inertial of the cross-section of the foundation and the foundation width respectively. In addition, it is recommended that, the proper soil modulus value is the one corresponding to v=0 for consistency with the deformation pattern of Winkler’s springs (compression with no lateral deformation). In this respect, the author offers an effective method for calculating the equivalent elastic constants (Eeq, veq) for horizontally stratified soil mediums supporting shallow foundations. The same method can also be applied to reducing any homogenous (E, v) soil medium to an equivalent one having veq=0 and modulus Eeq.
COMPRESSIVE STRENGTH OF GEOPOLYMER MORTAR USING GROUND FERRONICKEL SLAG AND FLY ASH
Authors: Kuri Jhutan Chandra , Khan Md Nabi Newaz , Sarker Prabir Kumar
Published: June 2020

A huge amount of ferronickel slag is produced as a by-product of manufacturing ferronickel, which is used in stainless steel and nickel alloy. This paper presents the effect of using different percentages of ground ferronickel slag (GFNS) with fly ash (FA) on the workability and compressive strength of geopolymer mortar. A mixture of NaOH and Na2SiO3 solutions was used as the alkaline activator. It was found that the flow of fresh mortar decreased with the increase of GFNS content. This is attributed to the higher fineness and angular shape of GFNS particles as compared to spherical fly ash particles. The mortar cube specimens were heat-cured at 60 °C for 24 hours. The compressive strength of geopolymer mortar using 100% FA was 54 MPa and it increased by 17%, 21% and 36% for using 25%, 50% and 75% GFNS as fly ash replacement, respectively. The strength increase is attributed to the increase of Si/Al ratio by GFNS that favoured the production of alkali aluminosilicate reaction products.
EFFECT OF LOAD BEARING MATERIALS ON SUSCEPTIBILITY TO BIOFILMS GROWTH
Authors: Kočí Václav , Maděra Jiří
Published: June 2020

Preventing a biofilms growth on exterior facades of buildings is one of the ways how to preserve the original buildings appearance and thus their proper aesthetical function. Since the biofilms growth is strongly conditioned by the hygric and thermal conditions on the surface, a proper hygrothermal performance and interactions between materials involved is essential. This paper studies an impact of load bearing material on surface conditions on a lime-cement plaster from the point of view of susceptibility to biofilms growth. An influence of autoclaved aerated concrete, solid brick and sandstone is studied when exposed to dynamic boundary conditions in form of reference climatic data. Being obtained using computational modeling of coupled heat and moisture transport, the results revealed a substantial influence in that respect. The best performance exhibited the autoclaved aerated concrete as the duration of convenient conditions for biofilms growth was lower by 40% when compared to solid brick and sandstone.
DEVELOPMENT OF LIME BASED, LOAD-BEARING MATERIALS FOR WALL CONSTRUCTION
Authors: O'Flaherty Fin , Khalaf Faraj , Starinieri Vincenzo
Published: June 2020

Construction of buildings in the UK is traditionally done using building materials such as concrete blocks, bricks and less so, timber. Although timber is a sustainable product, concrete blocks and bricks require a lot of energy input during fabrication, concrete especially being a large producer of CO2 during its manufacture. Reducing energy consumption either domestically or industrially is an important part of achieving the UK Government’s legally binding commitment to reducing greenhouse gas emissions by at least 80% (relative to 1990 levels) by 2050. New, low embodied energy construction materials are urgently required to enable the construction industry to revolutionize and drastically decrease its carbon footprint. The constituents of the materials investigated were selected based on low embodied energy criterion. To achieve this, lime was selected as the base material with hemp (fibers and shives) and PVAc used as additives. Specially selected nanomaterials were used as fillers. The constituents were combined in a manner, which led to different materials being developed, all exhibiting different characteristics. One characteristic was strength (load bearing) to eliminate the use of timber studding during construction. The results show that the highest strengths were achieved by mixing 10 wt. % hemp fiber, 4 wt. % nanozinc oxide and 12 wt. % PVAc at a 0.4 W/L ratio, yielding 17.7 MPa in compression and 7.3 MPa in flexure.
QUANTIFYING UNCERTAINTY IN SIMULATION MODELING
Authors: Thibault Jace , AbouRizk Simaan
Published: June 2020

Uncertainty can be defined as a state of either incomplete or otherwise bounded knowledge. Simulation models, and the engineering systems that they represent, often contain various types of uncertainty. Different approaches and theories can be applied to model these various types of uncertainty with a range of degrees in difficulty and accuracy. The objective of this paper is to explain the various types of uncertainty found in simulation models and to examine where uncertainty can be better represented or potentially reduced. To achieve this objective, a Monte Carlo Simulation model called the As-Planned Model is developed to estimate both cost and schedule using a risk-based approach for a simplified, Light Rail Transit construction project. After the project is complete, the As-Planned model is then compared to the project’s actual results. The resulting conclusions about various types of uncertainty are derived through both output comparison as well as uncertainty analysis.
EXPERIMENTAL INVESTIGATION ON STRENGTHENING OF REINFORCED CONCRETE COLUMNS WITH CARBON CONCRETE COMPOSITE
Authors: Holschemacher Klaus , Messerer Dennis , Polienko Wladislaw
Published: June 2020

The application of textile reinforced concrete is well-approved technique for strengthening of reinforced concrete members. When using carbon fiber meshes and carbon fiber reinforced polymer bars as reinforcement, this material is called carbon concrete composite. Based on the outstanding properties of carbon fibers, carbon concrete composite is characterized by high bending and tensile strength, and good durability. Therefore, carbon concrete composite is increasingly applied as replacement for ordinary steel bar or steel mesh reinforced concrete. It is favorable building material for production of new buildings and for strengthening of existing reinforced concrete members. In the context of strengthening of existing reinforced concrete columns, it is a usual procedure to cover the member’s surface with a thin layer of carbon concrete composite aiming on reduction of lateral strains of the core concrete when load is increasing. The result is an increased load-bearing capacity of the strengthened column. However, there is insufficient knowledge about the influence of curvature of the carbon meshes in circular cross-sections and in the corners of rectangular cross-sections on their load-bearing capacity. For this reason, an experimental program started to study the influence of curvature, number and type of mesh layers and specimen dimensions on structural behavior of strengthened columns under axial loading. As main outcome it can be stated that besides the curvature other parameters like yarn properties are of essential importance.
EFFECT OF APPLIED INTERIOR THERMAL INSULATION SYSTEMS ON THE ENERGY PERFORMANCE OF A HISTORICAL/CONTEMPORARY MASONRY
Authors: Kočí Jan , Maděra Jiří , Jerman Miloš
Published: June 2020

The paper is aimed at the investigation of the effect of applied internal thermal insulation system on the energy performance of historical and contemporary masonry. For that reason, sandstone masonry and ceramic brick masonry were selected as representative examples and their energy performance was analyzed using hygrothermal simulations in two states. First, each wall was simulated without being thermally insulated to obtain reference values of energy performance. Then, the walls were thermally insulated – sandstone masonry with mineral wool and ceramic brick masonry with wood fiber insulation – and new performance after wall retrofitting was quantified. All simulations are performed for two different locations to analyze the effect of boundary conditions as well. The paper demonstrates how the computational simulation using advanced moisture-dependent material parameters can be utilized for accurate assessment of thermal and energy performance of building envelopes under dynamic conditions, which is often omitted by national standards or black-box simulation tools. The results clearly indicate that application of thermal insulation on the interior side can significantly contribute to the reduction of annual heat losses varying from 66.7% to 87.2% depending on the material of thermal insulation and the location of the building.
DESIGN WIND PRESSURE COEFFICIENTS FOR LOW-RISE GABLE-ROOFED STEEL BUILDINGS
Authors: Gunji Seiya , Sato Kosuke , Uematsu Yasushi
Published: June 2020

The present paper discusses the wind pressure coefficients for the main wind force resisting systems of low-rise gable-roofed steel buildings, based on a wind tunnel experiment and a two-dimensional frame analysis. The wind pressure coefficients should be determined so that they reproduce the maximum load effects. Here, focus is on the bending moments involved in the members as the load effects. The Load Response Correlation (LRC) method is employed for evaluating the equivalent static wind pressure coefficients. Using the time history of wind pressure coefficients, the maximum load effects were computed for all combinations of frame location and wind direction. The results indicate that the most critical condition occurs on the windward frame in a diagonal wind. The largest bending moment was compared with that predicted from the wind pressure coefficients specified in the Japanese building standards, which are based on the area-averaged mean wind pressure coefficients. Finally, more reasonable wind pressure coefficients for designing the main wind force resisting systems are proposed.
PAPER-SHADE: DEVELOPMENT OF SUSTAINABLE MODULAR BUILDING SHADING SYSTEMS UTILIZING RECYCLED PAPER TOWARDS SERIAL PRODUCTION
Authors: Cleanthous Adonis , Menikou Markella
Published: June 2020

The paper will present an ongoing research for the design and manufacturability of modular building shading systems utilizing recycled paper as the primary material ingredient. The Paper-Shade project proposes a radically new solution: surplus recycled paper into a building construction product. The research aims to develop prototypes of serially manufactured modules that are sustainable in their materiality, manufacturing process, performances, life span cycle, as well as eventual re-cycling. The methodology utilized throughout the research is primarily a hands-on one. The research consortium consists of academic, industry and professional practice partners. The prototypes therefore develop through cyclical processes involving case-study assessments (theoretical and physical), cataloguing of data and outlining directives, defining desired-for specifications, testing through simulation, physical testing and laboratory results. Serial production possibilities as well as product affordability and maximized building energy performance are also considered. The Paper-Shade project may be considered as a modern-day version of vernacular building systems such as adobe bricks. It is also a new take on the modernist era’s concrete shading modules that were extensively and successfully used in the past in hot climatic zones but unfortunately forgotten during the recent decades. The project aims to revive intelligent shading systems by prototyping sustainably produced and performing shading modules towards an improved built environment.
Adaptación metodológica en el diseño y desarrollo urbano de bajo impacto para el manejo de aguas pluviales en Colima, México
Authors: Isabeles Deniz Karen Gricela , Olavarría Sánchez Ángel Manuel , Quintanilla Montoya Ana Luz , Ríos Aguilar Jesús
Published: June 2020

Contexto: Hoy en día, las ciudades requieren la implementación de nuevas experiencias de transformación urbana, debido a que la urbanización es responsable del 70 % de emisiones globales de CO2. El reto que confronta en materia urbana es hacer frente al CCG a nivel ciudad, mediante infraestructura multifuncional.

Método: El presente estudio se llevó a cabo bajo la perspectiva del diseño y desarrollo urbano de bajo impacto (LIUDD, por su sigla en inglés) contextualizando el marco francés de planeación urbana, en el cual, el manejo de agua es prioritario. La ciudad de Colima presenta un crecimiento horizontal desordenado y, en consecuencia, la extensión de áreas impermeables ha provocado escorrentías, inundaciones y congestionamiento vial.

Resultados: La zona norte-poniente presenta un área de oportunidad para tratar dichas problemáticas, como se analizó en esta investigación. La zona de estudio presenta un alto nivel de ocupación del suelo (COS=0,76-1,00) obteniendo un coeficiente de escorrentía CE=0,96. Además, presenta una baja densidad poblacional (51-100 hab/ha), con un 92 % de motorización. La vialidad ocupa el 91 % de la superficie de espacio público, por lo que representa un área de oportunidad para la infraestructura multifuncional. Se propone que mediante técnicas de drenaje urbano sostenible implementadas en vialidades principales, se reduzca el CE a 0,90, y el volumen de inundaciones en un 203 %, priorizando los modos activos de transporte.

Conclusiones: Desarrollar e implementar una gestión integral del agua, sustentada en un cuadro reglamentario que priorice el LIUDD, puede paliar el estrés hídrico en esta y otras ciudades con problemáticas comunes, mediante la creación de una coordinación integrada por representantes de diversos sectores. Lo anterior, con el objetivo de poder gestionar el espacio público, y de impulsar proyectos multifuncionales para manejo de aguas pluviales, movilidad y desarrollo urbano que puedan ser útiles en la aplicación de nuevas maneras de planificar nuestras ciudades y mitigar los riesgos climáticos.
Homeostasis de la industria de manufactura en Jalisco, México: el kaizen como negentropía en la logística de embarques
Authors: Toscano Rentería Irma Aracely , Brito Cervantes Esmeralda , Magaña Moya Santos , Gonzaléz Pérez Mario Guadalupe
Published: June 2020

Contexto: En México, el comercio internacional experimenta un aumento al que se suman empresas internacionales del área de manufactura en el estado de Jalisco. La investigación revisa la homeostasis de las empresas de ensamble y exportación, con la idea de mejorar la logística de embarques para automatizar e incrementar la productividad, a través del desarrollo y aplicación de la herramienta de mejora continua denominada kaizen.

Método: Esta investigación parte de un enfoque sistémico. En este sentido, para identificar la homeostasis de la empresa se obtuvieron datos e información de las actividades que desarrolla el área logística, así como políticas y estrategias. Posteriormente, mediante el diagrama de Ishikawa se analizaron la relación causa-efecto y a través de un mapeo de procesos se determinó la problemática de las áreas de compra, producción y almacén. Finalmente, se plantearon varias alternativas de solución para el mejoramiento de la gestión. Asimismo, para el desarrollo de las soluciones, se confrontaron los problemas y soluciones relacionándolos con el impacto en el nivel de servicio, y se hizo un comparativo entre el antes y después de implementar el kaizen.

Resultados: El estudio se centra en el funcionamiento de la logística de embarques para automatizar el proceso y evitar los cuellos de botella. De esta manera, las ordenes que no se embarcan a tiempo se convierten en código A (órdenes urgentes) y provocan que el cliente califique un 60 % la productividad. Por ello, al implementar el kaizen se logra subir considerablemente hasta en un 35 % por año, con muestras de satisfacción y calificación del 95 %. Cabe mencionar que este kaizen se llevó a cabo en el proyecto de Fru’s & Opt.

Conclusiones: La homeostasis actual de las herramientas mencionadas en el estudio son básicas y necesarias. Igualmente, se siguen actualizando y adaptando herramientas de mejora continua (negentropías); por ejemplo: heijunka, jidoka, SMED, lean manufacturing, just in time, Sistema de Producción Toyota (TPS), 5S o gemba, ya que es una forma de incrementar la productividad, bajar costos y aumentar la capacidad de competitividad para atraer a más mercados internacionales.