767 research outputs found
Investigation of the Effect of Rising Temperature and Traffic Loading on the Behaviour of Rigid Pavements to Minimise Maintenance Requirements – Case Study of Lebanese Roads
The aim of this project is to study the effects of high temperature on the performance of rigid pavements including that of Lebanese roads and to develop suitable design and maintenance approaches that enable such pavements to sustain high loading of temperature and traffic.
The objectives are to gain a deeper understanding of the condition and performance of existing highway rigid pavements and the need for a durable pavement. More specifically, to fully understand the effect of climate change in terms of temperature changes on rigid pavements and to identify structural layers configuration and material properties that enable the pavement to sustain high temperature and heavy traffic loading, and to develop more effective and sustainable rigid pavement structures to minimise maintenance requirements. The work also includes the design of suitable overlays to maintain and extend the life of the existing rigid pavements.
The methodology used to complete the project is by analysing pavement deflection and the effect of high temperature using specialised highway and structural analysis software, particularly the packages KENPAVE, STREETPAVE12 and ABAQUS.
The main findings are that fatigue and erosion are the two most significant failing scenarios for rigid pavement, but more specifically, as the temperature increases, the cracking index increases which may lead to fatigue failure. Finite element models and analyses were used to determine the distress caused by traffic loading and high temperature. This research has found that the main factors that strengthen the performance and sustainability of the rigid pavements under high temperature and traffic loading are: thicker slab, high modulus concrete, strong and thicker foundation layers and a subgrade with high CBR%, in addition to a strong and thicker overlay to extend the life of the pavement.
The key conclusions are that rising temperatures and high traffic loading have been identified as having a major effect on the performance of rigid pavement, leading to fatigue failure criteria. Erosion is also a common failure criterion which establishes itself at times of high traffic loading. It has been found here that the cracking index of the concrete slab increases when the air temperature changes from 20°C to 60°C. At higher temperatures and with thinner slabs, the cracking index occurrence increases. In conclusion, in Lebanon a minimum of 260 mm rigid pavement would be more suitable to reduce pavement failing under fatigue criteria
Treatment of tumour recurrence after resection of hepatocellular carcinoma. Analysis of 97 consecutive patients
OBJECTIVE:
To evaluate the long-term results of aggressive treatment of HCC recurrence.
METHODS:
Two hundred and nine consecutive patients underwent hepatic resection for HCC in our hospital. Tumour recurrence was diagnosed in 97 (51%) of the 190 patients with curative resection. Sixteen underwent hepatic resection: two right hepatectomies, one three-segmentectomy, one left hepatectomy, five two-segmentectomies, six segmental resections and one subsegmentectomy. Two patients with metastasis in the spine were submitted to a vertebral body resection. Twenty-five patients were treated with percutaneous ethanol injection or intra-arterial chemoembolization. Fifty-four patients with a poor performance status and liver function or multiple extra hepatic recurrences did not receive any treatment.
RESULTS:
There were no operative deaths. The postoperative mortality rate was 5.5% (one patient). The cumulative overall survival after the second resection was respectively 89%, 46% and 31% at 1, 3 and 5 years. There was a significant difference in survival between patients treated with repeat resection and those submitted to a non-surgical or conservative treatment (p<0.0001). There were no differences in operative deaths, postoperative mortality and morbidity between the first and second hepatic resection.
CONCLUSIONS:
Aggressive management with combined resection or loco regional therapy for intrahepatic recurrence and resection of isolated extra-hepatic recurrence may offer long-term survival in selected patients. Second liver resection for recurrence of HCC can be safely performed
Regulation of ABCA1 expression and cholesterol efflux during adipose differentiation of 3T3-L1 cells.
Adipose cells specialized in energy storage, contain large intracellular triglyceride-rich lipid droplets, are enriched with free cholesterol, and express sterol-regulated transcription factors such as liver X receptor (LXR). The recent identification of the LXR-dependent ATP binding cassette transporter A1 (ABCA1) pathway for cholesterol release from peripheral cells has led us to address the question of the expression and function of ABCA1 in adipocytes. In 3T3-L1 adipose cells, we observed a strong induction of ABCA1 mRNA during adipose differentiation, but only limited variations in ABCA1 protein. Lipid efflux onto apolipoprotein A-I (apoA-I), which depends on ABCA1, was comparable in adipocytes and preadipocytes, demonstrating a differential regulation of ABCA1 mRNA and cholesterol efflux. We also found that total cell cholesterol remained stable during differentiation of 3T3-L1 cells, but membrane cholesterol was lower in adipocytes than in preadipocytes, suggesting redistribution of cholesterol to the lipid droplet. Finally, we show that under standard lipolytic stimulation, 3T3-L1 adipocytes do not release cholesterol onto apoA-I, a process that required long exposures to lipolytic agents (24 h). In conclusion, despite large induction of ABCA1 mRNA during differentiation, cholesterol efflux through the ABCA1 pathway remains limited in adipocytes and requires prolonged lipolysis. This is consistent with the view of the adipocyte behaving as a cholesterol sink, with plasma cholesterol-buffering properties
A Method Based on a Nonlinear Generalized Heisenberg Algebra to Study the Molecular Vibrational Spectrum
We propose a method, based on a Generalized Heisenberg Algebra (GHA), to
reproduce the anharmonic spectrum of diatomic molecules. The theoretical
spectrum generated by GHA allows us to fit the experimental data and to obtain
the dissociation energy for the carbon monoxide molecule. Our outcomes are more
accurate than the standard models used to study molecular vibrations, namely
the Morse and the -oscillator models and comparable to the perturbed Morse
model proposed by Huffaker \cite{hf}, for the first experimental levels. The
dissociation energy obtained here is more accurate than all previous models
The Constructability of the Cheops Pyramid
Abstract
The aim of this paper is to forecast the methodology by which Cheops Pyramid as a historic building was built, based on notions of modular patterns discovered within the following planar illustrations, starting at the apex and descending to its grand base.
Some of Cheops’ heritage in terms of form and function has existed for millennia, as its mark was recapped with a front line that was constructed thousands of years before. Such a voyage through the missing captures of the building techniques wouldn’t have occurred without the incidental outcome that resulted from overlaying the various pixelated plans of block arrangements on the floor maps of Cheops. This building is believed to exhibit norms similar to those governing the balance between matter and void in the universe.
By assessing this historical masonry structure of Giza, we have come to find some regulatory approaches concerning how to asses the construction of such a building by predicting their interiors, spatial definitions, customs, and layouts. As there are no major records of their plans, the best practice anticipated in this paper is to modularize the figurative appearance of such buildings, by imitating themes of the repetitive patterns of past regional Egyptian architecture seen as pixels. This led to the fundamental solution to such a dilemma in building construction.
Keywords: Cheops, Pyramid, Balance, Historical Building
Nucleus accumbens volume is related to obesity measures in an age‐dependent fashion
Motivation theories of obesity suggest that one of the brain mechanisms underlying pathological eating and weight gain is the dysregulation of dopaminergic circuits. While these dysregulations occur likely at the microscopic level, studies on gray matter volume reported macroscopic differences associated with obesity. One region suggested to play a key role in the pathophysiology of obesity is the nucleus accumbens (NAcc). We performed a meta‐analysis of findings regarding NAcc volume and overweight/obesity. We additionally examined whether gray matter volume in the NAcc and other mesolimbic areas depends on the longitudinal trajectory of obesity, using the UK Biobank dataset. To this end, we analysed the data using a latent growth model, which identifies whether certain variables of interest (e.g. NAcc volume) is related to another variable's (BMI) initial values or longitudinal trajectories. Our meta‐analysis showed that, overall, NAcc volume is positively related to BMI. However, further analyses revealed that the relationship between NAcc volume and BMI is dependent on age. For younger individuals such relationship is positive, while for older adults it is negative. This was corroborated by our analysis in the UK Biobank dataset, which includes older adults, where we found that higher BMI was associated with lower NAcc and thalamus volume. Overall, our study suggests that increased NAcc volume in young age might be a vulnerability factor for obesity, while in the older age decreased NAcc volume with increased BMI might be an effect of prolonged influences of neuroinflammation on the brain
Attentive Learning of Sequential Handwriting Movements: A Neural Network Model
Defense Advanced research Projects Agency and the Office of Naval Research (N00014-95-1-0409, N00014-92-J-1309); National Science Foundation (IRI-97-20333); National Institutes of Health (I-R29-DC02952-01)
Challenges for CO2 mitigation in the Lebanese electric-power sector
Similar to other developing countries the electricity sector in Lebanon is monopolized by a vertically integrated public utility, Electricite Du Liban (EDL). EDL's supply is characterized by frequent and lengthy power cuts that have given rise to an alternative, informal, and unregulated backup sector, which serves to satisfy electricity demand during the extended blackout periods. This paper examines the evolvement of the backup sector and its related CO2 emissions via the use of scenario analysis. The economic and energy policy implications of each scenario are discussed and a number of policy options are presented to ensure that the growth in CO2 emissions is contained. Results clearly indicate that the backup sector plays a critical role in the success of any greenhouse gas mitigation commitment undertaken by Lebanon. A clear strategy on dealing with this sector needs to be devised simultaneously if not prior to any climate change policy at the national level. © 2009 Elsevier Ltd. All rights reserved
Degradabilidade in situ de híbridos de milho e de capim-elefante colhidos em quatro estádios de maturidade
Dentre as forragens, a silagem de milho é amplamente utilizada pelos fazendeiros que visam explorar o máximo do potencial genético dos animais. No entanto, outros volumosos tropicais como o capim-elefante (Pennisetum purpureum) são mais produtivos e, portanto, mais baratos do que a silagem de milho. Nosso objetivo foi comparar a degradabilidade in situ do capim-elefante com a degradabilidade de híbridos de milho, colhidos em quatro estágios de maturidade. O experimento seguiu um delineamento de blocos ao acaso com sub-parcelas. Dois híbridos de milho: AG5011 e ZN8392 foram colhidos com 25, 30, 35 e 40% matéria seca (MS) na planta toda e separados na fração colmo + bainha + folhas e espigas. Capim elefante foi colhido 30, 40, 50 e 60 dias após o corte de nivelamento. As amostras secas e trituradas foram incubadas no rúmen por 0, 6, 12, 24, 48 e 72 h para cálculo da cinética da degradação ruminal da MS e da fibra em detergente neutro (FDN). O avanço da maturidade aumentou os teores de FDN e fibra em detergente ácido (FDA) do capim elefante e reduziu a degradabilidade da MS. Entretanto, a maturidade teve pouco efeito sobre os teores de fibra e a degradabilidade da MS da fração planta dos híbridos de milho. O capim elefante apresentou maior degradabilidade da FDN do que híbridos de milho, e não houve efeito da maturidade sobre a degradabilidade da FDN das duas espécies. A degradabilidade da fibra de capim-elefante não é pior do que a de híbridos de milho e, portanto a escolha da forragem deve ser feita com base em análises econômicas ao invés de assumir um menor potencial de produção em dietas a base de capim elefanteAmong tropical forages, corn silage is largely used by farmers trying to explore the maximum genetic potential from the animals. However, other tropical forages, such as elephant-grass (Pennisetum purpureum), are more productive and therefore cheaper to use than corn silage. Our objective was to compare the in situ degradability of elephant-grass with that from corn hybrids, all harvested at four stages of maturity. The experimental design followed a randomized block design with nested subplots. Two corn hybrids: AG5011, ZN8392 were harvested with 25, 30, 35, and 40% dry matter (DM) in the whole plant, and separated in stem + leaf sheath + leaf blade (stover), and cobs. Elephant-grass was harvested with 30, 40, 50 and 60 days after a leveling cut. Dried and ground samples were incubated in nylon bags inside the rumen for 0, 6, 12, 24, 48 and 72 h to estimate the kinetics of ruminal DM and neutral detergent fiber (NDF) degradation. The advance of maturity increased the NDF and acid detergent fiber (ADF) content in elephant-grass, and reduced its DM degradability. However, maturity had little or no effect on fiber content and DM degradability of corn stover. Elephant-grass had a higher NDF degradability than corn stover, and there was no effect of maturity on NDF degradability of either elephant-grass or corn stover. Fiber degradability of elephant-grass was not worse than that of corn stover, and therefore the choice of forage should be made on economical analysis rather than assuming an intrinsic low production potential for elephant-grass based diet
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Working sick and out of sorts: a cross-cultural approach on presenteeism climate, organizational justice and work-family conflict
A climate of presenteeism has important effects on employee well-being and the organization itself. Our study, based on surveys of health sector employees in six different countries (Brazil, Ecuador, Lebanon, Portugal, Russia and Spain) examines whether organizational justice plays a mediating role in the relationship between a presenteeism climate in the organization and work-family conflict (WFC). Our results indicate that the perception of organizational justice and the presenteeism climate do influence WFC. Moreover, higher levels of WFC were found in non-Latin countries. This study contributes to the work attendance and life balance field by providing cross-cultural empirical evidence corroborating the effect of justice and presenteeism climate on the WFC
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