bluuebunny/crossref_metadata_2025 huggingface dataset:
An Unusual Complication of Barotrauma at Altitude
Authors: Powell Marion R. , Hurley Leo D. , Richardson Tighe C.
Published: October 2015

BACKGROUND: A case of unilateral optic neuropathy secondary to barotrauma following a medial orbital wall fracture is presented.CASE REPORT: A 41-yr-old U.S. Air Force aviator presented for a routine periodic health assessment. Evaluation uncovered a suspected acquired
color deficiency in the right eye (OD). Subsequent discussions with the patient revealed a history of eye pain, redness, and proptosis during a flight overseas several years earlier. Local ocular examination demonstrated asymmetric optic nerve cupping, optic nerve pallor OD, a mild asymmetric
color deficit, and a significant visual field defect OD. Evaluation with magnetic resonance imaging revealed findings consistent with an old medial orbital wall fracture OD and optic nerve findings consistent with optic neuropathy. Follow-up evaluation by neurology and otorhinolaryngology
demonstrated only extensive sinus pathology. Based upon these findings, it is postulated that the member suffered a medial orbital wall fracture at altitude during ascent caused by expanding ethmoid sinus gases due to abnormal sinus anatomy with subsequent right optic nerve injury leading
to an optic neuropathy and subsequent visual sequelae.DISCUSSION: This case demonstrates one possible complication of active sinus disease while working in the aerospace environment. Several case reports have been published demonstrating the potential link between eye injuries and
working in an environment with fluctuating atmospheric pressure. However, literature addressing the specific in-flight environment causing such complications is lacking. Furthermore, the case supports the need for versatility and a broad knowledge base in practicing flight surgeons to evaluate
ocular pathology.Powell MR, Hurley LD, Richardson TC. An unusual complication of barotrauma at altitude. Aerosp Med Hum Perform. 2015; 86(11):994–998.
Clinical Markers Associated with Metabolic Syndrome Among Military Aviators
Authors: Rhee Chulwoo , Kim Jinho , Kim Ji-young , Chang Eunsuk , Park Se-young , Lee Wooyoung , Kang Hohyung
Published: October 2015

BACKGROUND: Due to the recent increase of metabolic syndrome (MetS) in the Korean population, this study was performed to investigate the prevalence of MetS among Republic of Korea (ROK) Air Force military aviators and its relationship with clinical markers.METHODS:
A cross-sectional study was performed among 911 aviators who filled out the lifestyle questionnaire and underwent medical examinations at the ROK Air Force Aerospace Medical Center. Clinical markers of aviators with MetS were investigated and odds ratios were calculated.RESULTS:
Among the 911 aviators, 90 (9.9%) were found to have MetS and the prevalence of subcomponents were: 31.7% elevated blood pressure, 25.3% elevated waist circumference, 19.0% impaired glucose tolerance, 16.6% elevated triglycerides, 7.9% reduced high density lipoprotein (HDL) cholesterol. Among
aviators, a significant statistical association was found between the diagnosis of MetS with the highest quartile of uric acid, white blood cell (WBC) count, and alanine transaminase (ALT) level. Adjusted odds ratio of MetS was 8.88 (3.16 ∼24.99) if all three clinical markers were at highest
quartile range.DISCUSSION: Despite the relatively low prevalence of MetS in ROK Air Force aviators, further preventive measures are required as the prevalence is expected to increase in the future. Aviators with high levels of WBC count, uric acid, and ALT should be examined for
MetS. Further comprehensive cohort study is required to link the elevation of clinical markers and development of MetS.Rhee C, Kim J, Kim J-Y, Chang E, Park S, Lee W, Kang H. Clinical markers associated with metabolic syndrome among military aviators. Aerosp Med Hum Perform. 2015;
86(11):970–975.
Elevated Circulating S100A12 Associates with Vascular Disease and Worse Clinical Outcome in Peritoneal Dialysis Patients
Authors: Isoyama Naohito , Machowska Anna , Qureshi Abdul Rashid , Yamamoto Tae , Anderstam Björn , Heimburger Olof , Barany Peter , Stenvinkel Peter , Lindholm Bengt
Published: October 2015

Background

The pro-inflammatory receptor of advanced glycation end-products (RAGE)-ligand S100A12 is thought to promote, whereas anti-inflammatory soluble RAGE (sRAGE) may protect against, vascular disease. We evaluated circulating S100A12 and sRAGE in relation to vascular disease, inflammation, nutritional status, and mortality risk in peritoneal dialysis (PD) patients.

Methods

Plasma S100A12 and sRAGE, biomarkers of inflammation, nutritional status, and comorbidities were analyzed in 82 prevalent PD patients (median age 65 years; 70% men; median vintage 12 months) and, for comparative analysis, also in 190 hemodialysis (HD) patients and 50 control subjects. Associations between mortality risk and concentrations of S100A12 and sRAGE were assessed in PD and HD patients after a mean follow-up period of 31 and 29 months respectively using a competing risk Cox regression model.

Results

In PD patients, median S100A12, sRAGE and S100A12/sRAGE were markedly higher than in controls, and S100A12 was 1.9 times higher and median sRAGE 14% lower compared with HD patients. In PD patients, S100A12 associated with C-reactive protein (ρ = 0.46; p < 0.001) and interleukin-6 (ρ = 0.38; p < 0.001), and, negatively, with s-albumin (ρ = -0.27; p < 0.05) whereas sRAGE associated negatively with body mass index (ρ = -0.37; p < 0.001), fat body mass index (ρ = -0.34; p < 0.001), and lean body mass index (ρ = -0.36; p < 0.001). Peripheral vascular disease or cerebrovascular disease (PCVD) was present in 28% of PD patients and, in multivariate analysis, associated mainly with high S100A12 (odds ratio [OR] 3.52, p = 0.04). In both PD and HD patients, the highest versus other tertiles of S100A12 associated with increased mortality. In contrast, sRAGE did not associate with PCVD or mortality in PD and HD patients.

Conclusions

Plasma S100A12 and sRAGE are markedly elevated in PD patients. Soluble RAGE was inversely related to body mass indices while S100A12 associated with increased inflammation, PCVD, and mortality, suggesting that S100A12 may identify PD patients at high risk for vascular disease and increased mortality.
Erythrocytes as Volume Markers in Experimental PD Show that Albumin Transport in the Extracellular Space Depends on PD Fluid Osmolarity
Authors: Braide Magnus , Delbro Dick , Waniewski Jacek
Published: October 2015

Background

Macromolecules, when used as intraperitoneal volume markers, have the disadvantage of leaking into the surrounding tissue. Therefore, 51Cr-labeled erythrocytes were evaluated as markers of intraperitoneal volume and used in combination with 125I-labeled bovine serum albumin to study albumin transport into peritoneal tissues in a rat model of peritoneal dialysis (PD).

Methods

Single dwells of 20 mL of lactate-buffered filter-sterilized PD fluid at glucose concentrations of 0.5%, 2.5%, and 3.9% were performed for 1 or 4 hours. Tissue biopsies from abdominal muscle, diaphragm, liver, and intestine, and blood and dialysate samples, were analyzed for radioactivity.

Results

The dialysate distribution volume of labeled erythrocytes, measured after correction for lymphatic clearance to blood, was strongly correlated with, but constantly 3.3 mL larger than, drained volumes. Erythrocyte activity of rinsed peritoneal tissue biopsies corresponded to only 1 mL of dialysate, supporting our utilization of erythrocytes as markers of intraperitoneal volume. The difference between the distribution volumes of albumin and erythrocytes was analyzed to represent the albumin loss into the peritoneal tissues, which increased rapidly during the first few minutes of the dwell and then leveled out at 2.5 mL. It resumed when osmotic ultrafiltration turned into reabsorption and, at the end of the dwell, it was significantly lower for the highest osmolarity PD fluid (3.9% glucose). Biopsy data showed the lowest albumin accumulation and edema formation in abdominal muscle for the 3.9% fluid.

Conclusion

Labeled erythrocytes are acceptable markers of intraperitoneal volume and, combined with labeled albumin, provided novel kinetic data on albumin transport in peritoneal tissues.
Stability of Antibiotics for Intraperitoneal Administration in Extraneal 7.5% Icodextrin Peritoneal Dialysis Bags (Stab Study)
Authors: Ranganathan Dwarakanathan , Naicker Saiyuri , Wallis Steven C. , Lipman Jeffrey , Ratanjee Sharad K. , Roberts Jason A.
Published: October 2015

Background and objectives

Patients with peritoneal dialysis (PD)-associated peritonitis may be advised to store PD-bags with pre-mixed antibiotics at home, although there is a paucity of antibiotic stability studies in the commonly used icodextrin solutions. The purpose of this study was to assess the stability of various antibiotics in PD-bags when stored at different temperatures over a 14-day period.

Methods

7.5% icodextrin PD-bags were dosed with gentamicin 20 mg/L ( n = 9), vancomycin 1,000 mg/L ( n = 9), cefazolin 500 mg/L ( n = 9) and ceftazidime 500 mg/L ( n = 9) as for intermittent dosing. Combinations of gentamicin/vancomycin ( n = 9), cefazolin/ceftazidime ( n = 9), and cefazolin/gentamicin ( n = 9) were also tested. Nine drug-free bags were used as controls. Bags were stored in triplicate at 37°C, room-temperature (25°C), and refrigeration (4°C). Antibiotic concentrations were quantified at various time intervals using validated chromatography. Storage duration was considered unstable if the concentration of the antibiotic dropped ≤ 90% of the initial value.

Results

Gentamicin was stable for 14 days at all temperatures. Vancomycin was stable for 4 days at 37°C and for 14 days at both 25°C and 4°C. The gentamicin and vancomycin combination was stable for 4 days at 37°C and for 14 days at 25°C and 4°C. Cefazolin alone was stable for 24 hours at 37°C, 7 days at 25°C, and 14 days at 4°C. Ceftazidime alone was stable for only 6 hours at 37°C, 2 days at 25°C, and 14 days at 4°C. The cefazolin and ceftazidime combination was stable for 24 hours at 37°C, 2 days at 25°C, and 14 days at 4°C. The cefazolin and gentamicin combination was stable for 1 day at 37°C, 4 days at 25°C, and 14 days at 4°C.

Conclusions

Antibiotics premixed in icodextrin PD-bags have varying stabilities with stability generally least at 37°C and best at 4oC, permitting storage for 14 days when refrigerated and pre-warming to body temperature prior to administration. Further research confirming the sterility of these antibiotic-containing bags is recommended.
Catheter Insertion and Perioperative Practices within the ISPD North American Research Consortium
Authors: Wallace Eric L. , Fissell Rachel B. , Golper Thomas A. , Blake Peter G. , Lewin Adriane M. , Oliver Matthew J. , Quinn Rob R.
Published: October 2015

Background

In general, efforts to standardize care based on group consensus practice guidelines have resulted in lower morbidity and mortality. Although there are published guidelines regarding insertion and perioperative management of peritoneal dialysis (PD) catheters, variation in practice patterns between centers may exist. The objective of this study is to understand variation in PD catheter insertion practices in preparation for conducting future studies.

Methods

An electronic survey was developed by the research committee of the International Society for Peritoneal Dialysis – North American Research Consortium (ISPD-NARC) to be completed by physicians and nurses involved in PD programs across North America. It consisted of 45 questions related to 1) organizational characteristics; 2) PD catheter insertion practices; 3) current quality-improvement initiatives; and 4) interest in participation in PD studies. Invitation to participate in the survey was given to nephrologists and nurses in centers across Canada and the United States (US) identified by participation in the inaugural meeting of the ISPD-NARC. Descriptive statistics were applied to analyze the data.

Results

Fifty-one ISPD-NARC sites were identified (45% in Canada and 55% in the US) of which 42 responded (82%). Center size varied significantly, with prevalent PD population ranging from 6 – 300 (median: 60) and incident PD patients in the year prior to survey administration ranging from 3 – 180 (median: 20). The majority of centers placed fewer than 19 PD catheters/year, with a range of 0 – 50. Availability of insertion techniques varied significantly, with 83% of centers employing more than 1 insertion technique. Seventy-one percent performed laparoscopic insertion with advanced techniques (omentectomy, omentopexy, and lysis of adhesions), 62% of sites performed open surgical dissection, 10% performed blind insertion via trocar, and 29% performed blind placement with the Seldinger technique. Use of double-cuff catheters was nearly universal, with a near even distribution of catheters with pre-formed bend versus straight inter-cuff segments. There was also variation in the choice of perioperative antibiotics and perioperative flushing practices. Although 86% of centers had quality-improvement initiatives, there was little consensus as to appropriate targets.

Conclusions

There is marked variability in PD catheter insertion techniques and perioperative management. Large multicenter studies are needed to determine associations between these practices and catheter and patient outcomes. This research could inform future trials and guidelines and improve practice. The ISPD-NARC is a network of PD units that has been formed to conduct multicenter studies in PD.
Burkholderia Cepacia Exit-Site Infection in Peritoneal Dialysis Patients—Clinical Characteristics and Treatment Outcomes
Authors: Yap Desmond Y.H. , Chan Jasper F.W. , Yip Terence , Mok Maggie M.Y. , Kwan Lorraine P.Y. , Lo Wai Kei , Chan Tak Mao
Published: October 2015

Background

Burkholderia cepacia is a hardy bacterium with intrinsic resistance to multiple antibiotics and high transmissibility. Opportunistic healthcare-associated B. cepacia infections among immunocompromised or critically ill patients have been reported, but there is limited data on the clinical characteristics and treatment outcomes of exit-site infection (ESI) in peritoneal dialysis (PD) patients.

Patients and methods

Patients who suffered from B. cepacia ESI from 1 January 2004 to 31 December 2014 were reviewed. The clinical characteristics and treatment outcomes of the patients and the antibiotic susceptibility patterns of the bacterial isolates were analyzed.

Results

Twenty-two patients were included for analysis. Eight patients (36.4%) had medical conditions which impaired host immunity, while 7 (31.8%) had pre-existing skin abnormalities. Three patients (13.6%) progressed to tunnel-tract infection and another 3 patients (13.6%) developed associated peritonitis. Fifteen patients (68.2%) responded to medical treatment while 7 (31.8%) required catheter removal. Eleven patients (50.0%) had recurrent B. cepacia ESI, which occurred at 7.8 months (95% confidence interval [CI] 0.1 – 19.4 months) after the first episode. Most B. cepacia strains were susceptible to ceftazidime (95.5%), piperacillin/tazobactam (95.5%), and piperacillin (90.9%). Besides aminoglycosides (80 – 100%), high rates of resistance were also observed for ticarcillin/clavulanate (90.9%).

Conclusion

Burkholderia cepacia ESI is associated with low rates of tunnel-tract infection or peritonitis, but the risk of recurrence is high. Most cases can be managed with medical treatment alone, although one third of patients might require catheter removal.
Relation between the microstructure and technological properties of porcelain stoneware. A review
Authors: Romero M. , Pérez J. M.
Published: October 2015

Porcelain stoneware is a strongly sintered ceramic material fabricated from ball clays-quartz-feldspar mixtures. Porcelain stoneware is characterized by its excellent technical and functional properties (low water absorption, high mechanical properties, resistant to chemical substances and cleaning agents, aesthetic possibilities …). These characteristic and technical features make that among the different types of ceramic tile, porcelain stoneware is the ceramic product that in the last years has best withstood the economic crisis in the construction sector. These properties are related to the microstructure of porcelain stoneware, which is a grain and bond type with large particles of filler (quartz), mullite crystals, a silica-rich amorphous phase and porosity. The understanding of the relationship between the microstructure and the properties of porcelain stoneware is hardly important for the development and design of these materials whose tendency is the manufacture of thinner tiles with higher dimensions but must continue to comply the specific technical requirements.
Seasonal variation in reproductive activity and biochemical composition of flat oyster (Ostrea edulis) in the Homa Lagoon, Izmir Bay, Turkey
Authors: Acarli Sefa , Lök Aynur , Kirtik Ali , Acarli Deniz , Serdar Serpil , Kucukdermenci Aysun , Yigitkurt Selcuk , Yildiz Harun , Nur Saltan Asiye
Published: October 2015

The reproductive cycle of the flat oyster, Ostrea edulis Linnaeus, 1758, in Homa Lagoon, Izmir Bay, Turkey was examined from August 2008 to July 2009. Gonad samples were analysed histologically in order to determine the sex ratio and gonad development stage. Overall, the sex ratio was recorded as 2.2% female, 42.6% male, 37% hermaphrodite and 17.9% inactive. Glycogen content showed considerable variations between August and February, but decreased gradually thereafter. However, glycogen did not directly affect the reproductive cycle. Total lipid content was positively correlated with temperature and inversely correlated with salinity. In addition, this parameter was influenced by the reproductive activity, which is correlated with the fluctuation of the condition index and gonad index (P < 0.05). However, the relationship between the protein index and the gonad index was negative (P < 0.05). The results of this study showed that protein was the major energy resource. The condition index varied between 2.69±0.91 (February) and 12.29±1.45 (April) during the year. With respect to meat yield, oyster quality changed from “fine” to “special”, except in December and February.
Size of catch, reproduction and feeding of the small-eye smooth-hound, Mustelus higmani (Carcharhiniformes: Triakidae), in Margarita Island, Venezuela
Authors: Tagliafico Alejandro , Hernández-Ávila Iván , Rangel Salomé , Rago Néstor
Published: October 2015

Mustelus higmani is categorized as “least concern” according to the red list of the International Union for Conservation of Nature, but gaps in population trends occur in most of its distribution range. In Venezuela, this species has local importance because it is part of typical dishes. The aim of this work is to analyse the population structure, reproduction and feeding of M. higmani from Margarita Island’s artisanal fishery landings for management purposes. Between 2006 and 2008, 2223 specimens were analysed: 1156 females (24.8-88.4 cm total length [TL]) and 1067 males (20-69.2 cm TL). Temporal variations in sex ratio and length class structure were detected. Changes in body size were detected throughout different years of sampling. A decrease in TL and an increase in immature specimens in the catch were observed in 2008. Mean length at maturity (L50) was estimated at 46.7 cm TL for females and 47.6 cm TL for males. Female fecundity was 4±1.8 embryos (n=388). Length at birth was between 20 and 29 cm TL, and no differences in sex ratio were detected for embryos. Feeding analyses (n=266 stomachs) showed a diet mainly based on decapod crustaceans, small fish, stomatopods and cephalopods. The trophic level was 3.3, which shows feeding based on benthic and demersal species of the continental shelf, especially crustaceans.
Evaluating the Impact of Blended Learning on Performance and Engagement of Second Language Learners
Authors: Jee Rebecca Y , O'Connor Gabriele
Published: October 2015

Despite initial participant enthusiasm for e-learning products, severe abandonment has plagued several commercially available e-learning materials intended for autonomous usage [1]. To mitigate attrition rates and provide maximally effective instruction fostering user interest and engagement, Voxy has designed an online learning program within the Task-Based Language Teaching (TBLT) framework, which provides English language learners authentic, relevant content in conjunction with online tutoring sessions. Early research by Voxy on how blended learning impacts performance and engagement has revealed that learners who participate in synchronous, one-on-one tutoring sessions are more engaged than learners who do not; not surprisingly, the learners who are more engaged also show greater proficiency improvements as well.
Digital Media as Support for Technical Vocational Training: Expectations and Research Results of the Use of Web2.0
Authors: Schulte Sven , Richter Tim , Grantz Torsten
Published: October 2015

Digital media as support for Technical Vocational Education and Training (TVET) learning processes have been increasingly tested in recent times. In Germany, for example, the Ministry for Education and Research and others have been supporting projects that develop and evaluate innovative didactical and technological models focussing on “Virtual Learning”, “Learning with Web2.0” or “Mobile Learning”. Above all in vocational education and with regard to the target group of media-affine young people, teachers have high expectations regarding pedagogical purposes and learning efficiency. The present article describes a project on a learning and communication platform that combines the advantages of digital media with the special feature of a cooperation of learning environments within the German Dual TVET System by making use of innovative pedagogical approaches for the shaping of more sustainable occupational learning. The results show examples of how a different (often quite unexpected) use of digital media for vocational learning processes by young people is justified.
E-learning Readiness and Absorptive Capacity in the Manufacturing Industry
Authors: Hattinger Monika , Eriksson Kristina , Malmsköld Lennart , Svensson Lars
Published: October 2015

The manufacturing industry constantly strive to develop the competencies of their expert production engineers in order to achieve and maintain a competitive advantage. Research shows that the absorptive capacity of a firm is central in order to reach such a goal. The absorptive capacity is the firm´s ability to recognize the value of new external information, assimilate it, and apply it to commercial ends, and thereby exploit the conditions for innovation. In this paper the concept of absorptive capacity is used as a lens for analyzing managerial rationales for engaging in technology enhanced competence development projects. Through interviews with key informants in 15 manufacturing firms we study the capabilities and readiness that organizations need for participation in e-learning initiatives. We present a framework of readiness for technology enhanced competence development comprised of the following interrelated constructs; awareness, e-learning maturity, dynamic capability and co-creativity. Results show a broad variation of levels within the constructs among the firms. Notable is the low level of e-learning maturity and dynamic capability. We argue that e-learning maturity is dependent on all four constructs.
Preliminary Results in the Development of a Database for Noise Maps
Authors: Moscovici Anca Maria
Published: October 2015

The control of roads traffic, of noise, of all other problems which occur on national road sections are much more manageable through Geographic Information Systems. The possibility of changing parameters in real time from a database, allows rapid information on problems encountered and efficient solutions at a more sustained rate.This paper presents a proposed solution to improve the Geographic Information System by adding noise data, by carrying out a case study on the road section Sag - Voiteg that connects Timisoara (Romania) and Belgrade (Serbia). The existing GIS system was established in 2012 according to the legislation in force at the time. As Year 2017 will mark the next stage of issuing the noise maps according to the rules set by CNOSSOS-EU, the measurements done for this study will follow these new methods. CNOSSOS-EU accurately describes the objectives and methodology requirements, establishes clear criteria for road traffic and sound propagation.The advantage of uniformity standards and methods of control in all EU Member States allows comparative studies on pollution, the number of people affected, etc.
Dynamic Response of Axially Moving Beams with Small Non-Idealities at Boundary Supports
Authors: Köstekci Ferid
Published: October 2015

The nonlinear response of an axially moving Euler-Bernoulli beam having one intermediate simple support and clamped boundaries with small non-idealities is examined. A small parameter representing real physical clearances at ends is used. The clamped support conditions mean that the beam is passing through two frictionless guides and one intermediate simple support placed between two guides. It is assumed that the beam has immovable boundaries at the outer ends. The assumption introduces nonlinearity because of stretching of neutral fibers. It is considered that the beam is axially moving along its length at a harmonically varying velocity about a constant mean value. In this paper variations at the velocities are assumed to be suitably weak. Differential equations governing the motion of the two sides of the beam are derived using variational formulation. A damping term is added into the equations. The method of multiple scales is applied to obtain approximate analytical solutions in this weakly nonlinear system. Non-ideal conditions at boundary supports of the beam are taken into consideration as small parameters at nonlinear equations. Solvability condition for the case of principal parametric resonance is derived, amplitude-phase curves of steady-state responses and stability conditions are investigated. It is found that the effect of small non-ideality at boundary supports has a role on nonlinear response: the width of unstable regions becomes larger with increase of non-ideality value.
Simplified 7 DOF Model of Car Vertical Vibrations for Small Pitch and Roll Angles
Authors: Dumitriu Dan N. , Chiroiu Veturia , Munteanu Ligia
Published: October 2015

This paper concerns a simplified 7 DOF model for car vertical vibrations. The classical 7 DOF of the considered 3D vertical model are: the vertical displacement of the gravity center of the car body, the roll and pitch angles of the car body and the four vertical displacements of the wheels centers. Using the x-y-z sequence of rotations parameterization, the Euler’s rotation equations concerning the roll and pitch angle are easily obtained. Small differences are observed between our car body rotation equations concerning the two pitch and roll angles and the same equations provided by Demić et al. [6]. For small pitch and roll angles, no differences were observed with respect with [6]. Also, no differences were observed concerning the other 5 dynamics equations of the 7 DOF model, the ones for the vertical displacements.The simplified 7 DOF car vertical dynamics model, comprising two rotation equations (for pitch and roll angles) and five dynamics equations concerning vertical displacements/accelerations, were integrated/simulated in Matlab. For small pitch and roll angles (a rather flat and smooth straight road profile was considered in our case study), the results obtained using the in-house 7 DOF model Matlab simulator are in very good agreement with the results provided by CARSIM.
Determination of the Eccentricity of a Rotor by Impulse Excitation Technique of Vibration
Authors: Crâştiu Ion , Bereteu Liviu , Simoiu Dorin
Published: October 2015

The aim of this paper is the development and validation of an impulse excitation technique to determine static imbalance of a rotor. The experimental measurement of the vibroacustic response is carried out by using a condenser microphone. In determining the center of mass three measurements are needed: one in plane flexure, and other out of the plane flexure, to which is added a measurement for a balanced rotor. By the means of Finite Element Method (FEM), the natural frequencies and shape modes of two rotor specimens are determined. The analysis is carried out in balanced condition as well as unbalanced one, after artificially induced imbalance. The vibration responses of the specimens, in free-free conditions, are carried out using algorithms based on Fast Fourier Transform (FFT). To validate the results of the modal parameters estimated using Finite Element Analysis (FEA) these are compared with experimental ones.
Experimental Determinations of the Damping Factor for Composite Sandwich Bars Reinforced with Two Carbon Fiber Layers
Authors: Miriţoiu Cosmin Mihai , Bolcu Dumitru , Burada Cristian Oliviu , Stănescu Marius Marinel
Published: October 2015

In this paper we will build some new and original composite sandwich bars reinforced with two layers of carbon fiber, with the core made of polypropylene honeycomb. Starting from the dynamic response of these bars that are in free vibration, we will establish a procedure to determine their damping factor per unit mass and per unit length. We will also determine the bars eigenfrequencies (for the first eigenmode). The bars will have the core with 10, 15 and 20 mm and the free lengths of: 200, 230, 260, 290, 320 and 350 mm. The eigenfrequencies can be used in a future research to determine the bars stiffness. The stiffness values are important if these type of composite bars are used as frames for concrete forming, because the displacements when the concrete is molded are smaller if the stiffness has high values.
Dynamical and Geometrical Aspects Regarding the Behaviour of a Railway Vehicle Running on Curved Routes
Authors: Ghita Eugen , Ursu-Neamt Gabriel
Published: October 2015

The authors analyze the dynamical and geometrical aspects regarding the behaviour of a locomotive running on curved routes . There were taken into account all the possible disturbing effects and all the forces and torques acting on the bogie frame and on the coaches or carriages. A sophisticated calculus model is proposed for the analytic investigation. The guidance and the vertical forces on the wheel, the derailment criterion and the spring vibration damping are the main subjects of the investigation.
Assessment of Occupational Risk of Exposure to Vibrations Based on ‘The Document for Safety to Professional Vibration’
Authors: Vasilescu Gabriel , Ghicioi Emilian , Kovacs Attila , Jitea Ciprian , Rus Daniela , Gheorghiosu Edward , Csaszar Tiberiu
Published: October 2015

This paper refers to research undertaken in order to substantiate and elaborate ²The document for safety to professional vibration², which constitutes a procedural instrument for highlighting the synthesized estimation process of traceability and professional risk assessment of exposure to this type of emissions. Based on the results of the risk assessment of occupational exposure to vibration, whether exposure action values are exceeded, the employer must establish and implement a program of technical and/ or organizational measures intended to reduce exposure to occupational vibration.
Evaluation of the Human Body Equilibrium in a Vibration Environment
Authors: Barbu Daniela Mariana , Baritz Mihaela Ioana
Published: October 2015

In the human body, vibrations are generated by internal or external sources. Because of the soft tissues, bones, joints, internal organs and also because of its anatomical particularities components in general, the human body is a complex vibratory system. The vibrations from external sources can be transmitted to the human body when it is positioned in different manners: standing, sitting, recumbent and moving or at work. The effect of vibration on the human body is related to the natural frequency of affected parts in the human body. This paper studies the dynamic characteristics of a human body system in a vibration environment and sets limits to which the balance is affected. The main result is a multi degrees of freedom lumped parameter model. The model provides an analytical tool for human body dynamics research. The relative displacements of human parts are evaluated, which can be a basis for the assessment of vibration risk and setting limits for keeping human balance.
Laser Scanning Vibrometry and Holographic Interferometry Applied to Vibration Study
Authors: Breaban Florin , Debuchy Roger , Defer Didier
Published: October 2015

The applications of high performance materials in the aerospace and in the automotive technology in the next years need to develop new vibration study, nondestructive testing, predictive maintenance and industrial control methods.The Laser Scanning Vibrometry and Holographic Interferometry methods of vibration study and nondestructive testing by modal analysis are described. The Laser Scanning Vibrometer PSV 400 is made by Polytec GmbH and the PSV software reconstructs the 3D model of the measured micro-deformation of the object. The holographic laser system HLS-3 from Lumonics Inc. has 100 MW ruby laser peak power and 30 ns pulse width.Using mechanical excitation to induce a measurable vibration, the Laser Scanning Vibrometry and Holographic Interferometry modal analysis measurements show up the vibrational signatures and the damaged areas of the objects made by high performance materials - polymers, composites.
Outlooks on the Management System Based on ISO 17025, Applied in Acoustics and Vibration Laboratories
Authors: Calota Iulian Virgil
Published: October 2015

This paper is a point of view about the need and benefits of implementing of a quality management system, based on ISO 17025, in an acoustic and vibration testing laboratory. Both management and technical requirements are discussed.
Accurate Frequency Evaluation of Vibration Signals by Multi-Windowing Analysis
Authors: Minda Andrea Amalia , Gillich Nicoleta , Mituletu Ion Cornel , Ntakpe Jean Louis , Manescu Tiberiu , Negru Ionica
Published: October 2015

Accurate frequency evaluation is very important in the damage detection processes because the dynamic response is less sensitive to damage. Therefore, to be able to detect transverse cracks in early stage, it is necessary to read precisely the frequencies. In the literature are presented several methods, more or less complex and resource consuming, destined to improve the frequencies readability. In practical applications simple and fast methods for frequency evaluation are requested; the process should be adequate to be automated. The paper presents an original method for identifying the correct frequency of generated or acquired signals. The method is based on the analysis of the original signal cropped by rectangular windows in order to rearrange successively the spectral lines aiming to find the highest peak achieved in a region of interest for the frequency-amplitude pairs.
Free Oscillations of a Nonlinear Oscillator with an Exponential Non-Viscous Damping
Authors: Ene Remus Daniel , Marinca Vasile , Marinca Bogdan
Published: October 2015

This paper deals with the nonlinear oscillations of an exponential non-viscous damping oscillator. An analytic technique, namely Optimal Homotopy Perturbation Method (OHPM) is employed to propose an analytic approach to solve nonlinear oscillations. Our procedure proved to very effective and accurate and did not require a small or large parameters in the nonlinear equation or in the initial conditions. An excellent agreement of the approximate frequencies and periodic solutions with the numerical ones has been demonstrated.
Determination of Noise Level Specific to Pyrotechnic Articles for Professional Use, in Order to Evaluate the Level of Professional Risk
Authors: Vasilescu Gabriel , Kovacs Attila , Ghicioi Emilian , Rus Daniela , Gheorghiosu Edward , Jitea Ciprian , Csaszar Tiberiu
Published: October 2015

The paper presents a theoretical and practical approach to the concept of risk assessment of exposure to noise, specific to activity for use of pyrotechnic articles Category 4, from the perspective of ensuring the security of the effect resulting after fireworks displaying with these types of pyrotechnic products. For estimation and risk assessment using these types of products, researches has been undertaken to make an evaluation process procedure in order to provide data and information to prevent and combat the causes that may create a hazard.
Effects of Coal Bottom Ash on the Compressive Strength of Portland Cement Mortar
Authors: Ibrahim Ali Huddin , Choong Kok Keong , Megat Johari Megat Azmi , Md Noor Shahril Izham , Zainal Nur Liyana , Ariffin Kamar Shah
Published: October 2015

The possibility of utilizing treated coal bottom ash as a partial replacement of Portland cement was examined through compressive strength test on mortar samples. A total of 16 batches of mortar mixtures with cement:sand ratio of 1:2.5 and 1:2.75 were prepared using two types of treated coal bottom ash. The chemical compositions including the unburned carbon of coal bottom ash were also analyzed. In order to remove the excess unburned carbon which will affect the potential pozzolanic properties, the coal bottom ash was heated at 550 ± 50oC and 700 ± 50°C for 60 min in an electrical furnace.The results showed that compressive strength of mortar mixtures with cement:sand ratio of 1:2.5 and 1:2.75 containing treated coal bottom ash which was heated at 550oC results in an increase in compressive strength. At 10% and 20% of treated coal bottom ash replacement levels to Portland cement, the compressive strength of the mortar mixture was significantly improved at the age of 28 days. The compressive strength of the mortar mixtures at early ages gives lower strength as compared to the plain Portland cement mortar. However, the effect of treated coal bottom ash that was heated at 700°C is to reduce the compressive strength of the mortar mixtures except for mixture with cement:sand ratio of 1:2.5 containing 10% coal bottom ash at 56 days.
Experimental Study on Lateral -Torsional Buckling of Triangular Web Profile Steel Section
Authors: Hasan Hazwani , De’nan Fatimah , Choong Kok Keong
Published: October 2015

Triangular web profile (TriWP) is a structural steel section made of two flanges connected to a web plate of triangular profile. The ability of TriWP to resist lateral–torsional buckling (LTB) is one of the most important criteria considered in the design of this steel section. This study examined the LTB behavior of TriWP steel section and determined the buckling moment resistance (Mb,Rd) for TriWP. Beam specimens were analyzed using a four-point bending test. Four types of specimen sizes were used: 200 mm × 100 mm × 6.3 mm × 6 mm; 200 mm × 100 mm × 9 mm × 6.3 mm; 200 mm × 100 mm × 8 mm × 6 mm; and 200 mm × 100 mm × 6 mm × 5 mm sections. Testing results for all specimen sizes showed that the values for Mb,Rdof the TriWP steel sections were higher than those of the flat web section. The percentage difference of Mb,Rdfrom the experimental results for all specimen sizes ranged from 10.38% to 17.37%. The percentage difference of Mb,Rdof the experimental and design values based on manual calculation by using Eurocode 3 ranged from 9.13% to 43.8%.
Experimental Study on Reinforced Concrete Box Beam Strengthened by CFRP under Combined Action
Authors: Ma Sheng Qiang , Muhamad Bunnori Norazura , Choong Kok Keong
Published: October 2015

An experimental investigation was presented in this paper on reinforced concrete box beams subjected to shear, torsion, and bending moment strengthened by carbon fiber reinforced polymer (CFRP). Eight box beams were cast and separated into two groups according to two different torque-to-shear and torque-to-bending moment ratios. Three box beams from each group strengthened by CFRP in different configurations and one control box beam were tested. The main parameters of this experiment were the different ratios and configurations, including U-jacket layers and U-jacket strips with or without longitudinal strips. The cracking and failure mode, effect of wrapping configuration, torsional capacity, and behavior of the different torque-to-shear and torque-to-bending moment ratios were studied in the paper.
Influence of People Walking on Floor Performance due to Low Level Vibration
Authors: Tuan Chik Tuan Norhayati , Yabi Shurl , Wan Ibrahim Mohd Haziman , Yusoff Nor Azizi , Majid Taksiah A. , Alexius Asiew Rachel
Published: October 2015

Abstract. Vibration in building is one of the important problems which need to consider, especially in designing the floor. Floor vibrations are generally caused by dynamic loads applied particularly by human activity especially walking. Although it is specified as low level amplitude, walking induced vibrations can cause discomfort to human occupants and alarming for a certain items of precision sensitive equipment. This paper investigates the vibration response on floor performance due to one, three and five of people walking. Laser Doppler Vibrometer was used to obtain vibration data when people are walking. Further analysis was carried out by using finite element software package ANSYS to simulate the floor under vibration inputs to obtain natural frequency and mode shapes of the floor structure. The vibration data was then analysed in ModalV analysis to generate the vibration response. Then, the results were checked against the vibration criteria level guideline as a crude tool comparison. As a result, the numbers of people walking were influenced the floor performance, which indicated five peoples walking show the highest response up to ISO level due to vibration compared with one people walking.
Lightweight Building Materials of Geopolymer Reinforced Wood Particles Aggregate – A Review
Authors: Sarmin Siti Noorbaini
Published: October 2015

Lightweight constructions materials provide better thermal insulations properties for buildings. Using lightweight’s aggregates, such like wood particles is one of the most common ways for making lightweight building materials. The low cost and availability of wood particles made it the best ultimate materials preference in production of composites construction materials. Geopolymer, the alkali-activation cement-based materials have been proven can be used to produce lightweight materials. In additional, geopolymer possess excellent mechanical properties and significant reduction in CO2 emissions compare to ordinary Portland cement. The use of environmentally friendly building construction materials has become increasingly important. This paper presents a review on producing lightweight building materials from geopolymer with wood particles as an aggregate.
Numerical Models of Hysteretic Steel Damper with a Hollow Diamond Shape for Energy Dissipation
Authors: Teruna Daniel R. , Majid Taksiah A. , Budiono Bambang
Published: October 2015

Numerical studies were conducted to evaluate the behaviour of a hollow diamond shaped hysteretic steel plate damper under in-plane cyclic loading. The combine hardening material model based on Chaboche kinematic hardening rule and exponential isotropic hardening rule was proposed to trace the cyclic hardening behaviour of the steel damper. For engineering design purposes, simplified models based on bilinear and trilinear models were also presented. Numerical results showed that hysteretic curve obtained from Chaboche model and the simplified models correlate well with experimental results. Furthermore, the validity of the simplified models is verified through a comparison of its hysteretic energy dissipation with the actual test data.
Performance of Recycled Aggregate Containing POFA as Additives for Cement
Authors: Suraya Hani A. , Mohd Haziman Wan , Jamaluddin Norwati , Zakaria Nurul Hazarine
Published: October 2015

Malaysia has been the largest producer and exporter of palm oil in the world, accounting for 52% of the total world oil in year 2006. The waste disposal problem from palm oil industry was increasing. In addition, the government also facing the problems when forced to allocate more landfill for the disposal of concrete waste. Nowadays, the by-product the palm oil mill has becoming potentially to be utilized as construction material in term as additives for cement. This paper discussed the water absorption and compressive strength of Recycled Aggregate Concrete (RAC) containing Palm Oil Fuel Ash (POFA). There are twelve (12) series of concrete mix containing POFA and recycled aggregate (RA) were used as additives for cement that have been indicated as POFA-0%, POFA-10%, POFA-20%, POFA-30% and RA-0%, RA-50% and RA-100%. The slump test was conducted to determine the performance of fresh concrete. The hardened concrete have been tested its compressive strength and water absorption of POFA-concretes at 7 and28 days of water curing ages. The results revealed that POFA-recycled aggregate concrete has lower water absorption and higher compressive strength comparedto recycled aggregate concrete without POFA. The optimum additional of POFA was 30% for concrete made with 100% natural aggregate (NA) produced higher compressive strength and lower water absorption.
Practical Method for Damage Evaluation Based on Point Estimate Considering Uncertainty of Structural Properties
Authors: Iiyama Kahori , Hoso Masataka , Ishida Takanori , Fujita Kohei , Yamazaki Yoshihiro , Ichimura Tsuyoshi , Wijerathne Lalith , Morikawa Hitoshi , Hori Muneo , Yamada Satoshi , Sakata Hiroyasu , Yamanaka Hiroaki , Hirose Soichi
Published: October 2015

This study introduces a practical method for evaluating structural damage based on a large-scale simulation targeting expansive areas, like whole cities. In such a seismic simulation that deals with numerous building structures, it is desirable to estimate the damage based on a stochastic evaluation considering the uncertainty of structural properties. This is because an accurate modeling of numerous building structures, according to each designed value, would require a great deal of time. However, a damage evaluation considering the model uncertainty generally involves numerous calculations and is inadequate for such a large-scale simulation. Therefore, we propose a method using the point estimate technique which can estimate the probability of damage under model uncertainty from a small number of calculations. The applicability and usefulness of the proposed method is evaluated by comparing it to the method based on a Monte Carlo simulation.
Study on Fluid Transport Properties between Normal Concrete Substrate and Green-USM-Reinforced Concrete (GUSMRC) Containing Ultra Fine Palm Oil Fuel Ash (U-POFA) as Repair Material
Authors: Hassan Mohd Helmi , Muhamad Bunnori Norazura
Published: October 2015

Corrosion of reinforcement is one of the causes of concrete deterioration by the water contained chloride ions and gas, for example hydrogen sulfide that penetrate into the concrete structures. By performing the related transport properties testing, it will fulfill the main objective of this research that is to investigate the fluid transport and bonding properties between normal concrete substrate (NC) and green USM reinforcement concrete (GUSMRC) containing ultra-fine palm oil fuel ash (UPOFA) as repair material. GUSMRC is the type of concrete that has been upgraded from the ultra-high performance fiber reinforces concrete (UHPFRC) with 50 % of UPOFA replacing the cement. Recently many researchers have found that the POFA can be used as partial cement replacement in the concrete which can improve the durability and also the fluid transportation properties. For the bonding properties, two types of surface treatment / roughness will be perform to investigate the greatest bonding and also the durability between NC substrate that act as an old structures with GUSMRC as new repair material. It’s important to perform the other related testing so that the future results obtained can be conclude either this new green ultra-high concrete can resist the harmful environmental aggression and also if it has an excellent bonding with the old concrete as a repair material.