Search results for: presence

Authors: Robert Pellerin, Michel Gamache, Remi Trudeau, Nathalie Perrier

Abstract:

The context of large engineering projects is particularly favorable to the appearance of engineering changes and contractual modifications. These elements are potential causes for claims. In this paper, we investigate one of the critical components of the claim management process: the calculation of the impacts of changes in terms of losses of productivity due to the need to accelerate some project activities. When project changes are initiated, delays can arise. Indeed, project activities are often executed in fast-tracking in an attempt to respect the completion date. But the acceleration of project execution and the resulting rework can entail important costs as well as induce productivity losses. In the past, numerous methods have been proposed to quantify the duration of delays, the gains achieved by project acceleration, and the loss of productivity. The calculation related to those changes can be divided into two categories: direct cost and indirect cost. The direct cost is easily quantifiable as opposed to indirect costs which are rarely taken into account during the calculation of the cost of an engineering change or contract modification despite several research projects have been made on this subject. However, proposed models have not been accepted by companies yet, nor they have been accepted in court. Those models require extensive data and are often seen as too specific to be used for all projects. These techniques are also ignoring the resource constraints and the interdependencies between the causes of delays and the delays themselves. To resolve this issue, this research proposes a simulation model that mimics how major engineering changes or contract modifications are handled in large construction projects. The model replicates the use of overtime in a reactive scheduling mode in order to simulate the loss of productivity present when a project change occurs. Multiple tests were conducted to compare the results of the proposed simulation model with statistical analysis conducted by other researchers. Different scenarios were also conducted in order to determine the impact the number of activities, the time of occurrence of the change, the availability of resources, and the type of project changes on productivity loss. Our results demonstrate that the number of activities in the project is a critical variable influencing the productivity of a project. When changes occur, the presence of a large number of activities leads to a much lower productivity loss than a small number of activities. The speed of reducing productivity for 30-job projects is about 25 percent faster than the reduction speed for 120-job projects. The moment of occurrence of a change also shows a significant impact on productivity. Indeed, the sooner the change occurs, the lower the productivity of the labor force. The availability of resources also impacts the productivity of a project when a change is implemented. There is a higher loss of productivity when the amount of resources is restricted.

Keywords: engineering changes, indirect costs overtime, productivity, scheduling, simulation

Procedia PDF Downloads 235

Authors: Yakup Ulusu, Numan Eczacıoğlu, İsa Gökçe, Helen Waller, Jeremy H. Lakey

Abstract:

Besides having the appropriate amino acid sequence to perform the function of proteins, it is important to have correct conformation after this sequence to process. To consist of this conformation depends on the amino acid sequence at the primary structure, hydrophobic interaction, chaperones and enzymes in charge of folding etc. Misfolded proteins are not functional and tend to be aggregated. Cysteine originating disulfide cross-links make stable this conformation of functional proteins. When two of the cysteine amino acids come side by side, disulfide bond is established that forms a cystine bridge. Due to this feature cysteine plays an important role on the formation of three-dimensional structure of many proteins. There are two cysteine amino acids (C44, C69) in the Tol-A-III protein. Unlike protein disulfide bonds from within his own, any non-specific cystine bridge causes a change in the three dimensional structure of the protein. Proteins can be expressed in various host cells as directly or fusion (chimeric). As a result of overproduction of the recombinant proteins, aggregation of insoluble proteins in the host cell can occur by forming a crystal structure called inclusion body. In general fusion proteins are produced for provide affinity tags to make proteins more soluble and production of some toxic proteins via fusion protein expression system like pTolT. Proteins can be modified by using a site-directed mutagenesis. By this way, creation of non-specific disulfide crosslinks can be prevented at fusion protein expression system via the present cysteine replaced by another amino acid such as serine, glycine or etc. To do this, we need; a DNA molecule that contains the gene that encodes for the target protein, required primers for mutation to be designed according to site directed mutagenesis reaction. This study was aimed to be replaced cysteine encoding codon TGT with serine encoding codon AGT. For this sense and reverse primers designed (given below) and used site-directed mutagenesis reaction. Several new copy of the template plasmid DNA has been formed with above mentioned mutagenic primers via polymerase chain reaction (PCR). PCR product consists of both the master template DNA (wild type) and the new DNA sequences containing mutations. Dpn-l endonuclease restriction enzyme which is specific for methylated DNA and cuts them to the elimination of the master template DNA. E. coli cells obtained after transformation were incubated LB medium with antibiotic. After purification of plasmid DNA from E. coli, the presence of the mutation was determined by DNA sequence analysis. Developed this new plasmid is called PtolT-δ.

Keywords: site directed mutagenesis, Escherichia coli, pTolT, protein expression

Procedia PDF Downloads 366

Authors: Redie Kidane Ghebrehawariat, Betiel Habte Hadgu, Filmon Berhane Kahsay, Rim Berhane Fisehaye, Samuel Haile Kahsay, Saron Yemane Yosief, Selemawit Mosazghi Gilazghi

Abstract:

A cross-sectional study was conducted from 22 February to 9 April 2022 on small, medium, and large holder dairy farms to determine the bovine mastitis prevalence and associated risk factors in the Anseba region, Eritrea. A total of 34 dairy farms and 193 dairy cows were randomly selected. Dairy cows were physically examined for any change on the udder and milk; a California mastitis test was performed to check sub-clinical mastitis; a closed-ended semi-structured questionnaire composed of 28 variables/risk factors (21 management risk factors and 7 animal-level risk factors) was used to determine the risk factors responsible for clinical and sub-clinical mastitis in the dairy cows. The overall cow-level prevalence of mastitis was 147 (76.2%). The animal level prevalence rate of clinical and sub-clinical mastitis was found to be 22 (11.4%) and 125 (64.8%), respectively, while herd level prevalence both for clinical and subclinical mastitis was found to be 14 (41.2%) and 26 (76.5%) respectively. Based on the already set P-value, which is <0.05, a number of risk factors were found to have a significant relationship with the occurrence of clinical and sub-clinical mastitis. Generally, animal risk factors such as animal age, parity, injury on the udder or teat, and previous history of mastitis presence of injury on the udder and lactation stage were risk factors with a significant relationship with the occurrence of clinical and sub-clinical mastitis. On the other hand, management risk factors with a significant relationship to the occurrence of clinical and sub-clinical mastitis were herd size, failure to milk mastitic cow, at last, educational level, floor type, failure to use a towel, using one towel for more than one cow and failure to practice mastitis test. From a total of 772 quarters, 280 (36.3%) were found positive for sub-clinical mastitis using the California mastitis test; of these, 70 (9%) were weakly positive, 90 (11.7%) were distinct positive, and 120 (15.5%) were strongly positive. Furthermore, 13 (1.7%) quarters were blocked. Quarter level prevalence was right front 80 (41.5%), left front 64 (33.3%), right hind 69 (35.8%) and left hind 67 (34.7%). The study has shown that mastitis is a major problem for dairy farms and the findings suggested that mastitis is one of the limiting factors in increasing milk production. Subclinical mastitis was found to be a devastating problem, and it occurred in all three breeds of lactating dairy cattle. Therefore, farmers should work hard to avoid the above-mentioned risk factors to minimize the infection of their dairy cattle by mastitis and thereby increase their profit. On the other hand, the Ministry of Agriculture, through the extension unit, should work in close contact with the farmers to increase awareness of the economic importance of the disease and associated risk factors.

Keywords: mastitis, prevalence, dairy cattle, Anseba, Eritrea

Procedia PDF Downloads 120

Authors: Antonina A. Shumakova, Sergey A. Khotimchenko

Abstract:

The relevance of research is associated, on the one hand, with an ever-increasing volume of production and the expansion of the scope of application of engineered nanomaterials (ENMs), and on the other hand, with the lack of sufficient scientific information on the nature of the interactions of nanoparticles (NPs) with components of biogenic and abiogenic origin. In particular, studying the effect of ENMs (TiO2 NPs, SiO2 NPs, Al2O3 NPs, fullerenol) on the toxicometric characteristics of common contaminants such as lead and cadmium is an important hygienic task, given the high probability of their joint presence in food products. Data were obtained characterizing a multidirectional change in the toxicity of model toxicants when they are co-administered with various types of ENMs. One explanation for this fact is the difference in the adsorption capacity of ENMs, which was further studied in in vitro studies. For this, a method was proposed based on in vitro modeling of conditions simulating the environment of the small intestine. It should be noted that the obtained data are in good agreement with the results of in vivo experiments: - with the combined administration of lead and TiO2 NPs, there were no significant changes in the accumulation of lead in rat liver; in other organs (kidneys, spleen, testes and brain), the lead content was lower than in animals of the control group; - studying the combined effect of lead and Al2O3 NPs, a multiple and significant increase in the accumulation of lead in rat liver was observed with an increase in the dose of Al2O3 NPs. For other organs, the introduction of various doses of Al2O3 NPs did not significantly affect the bioaccumulation of lead; - with the combined administration of lead and SiO2 NPs in different doses, there was no increase in lead accumulation in all studied organs. Based on the data obtained, it can be assumed that at least three scenarios of the combined effects of ENMs and chemical contaminants on the body: - ENMs quite firmly bind contaminants in the gastrointestinal tract and such a complex becomes inaccessible (or inaccessible) for absorption; in this case, it can be expected that the toxicity of both ENMs and contaminants will decrease; - the complex formed in the gastrointestinal tract has partial solubility and can penetrate biological membranes and / or physiological barriers of the body; in this case, ENMs can play the role of a kind of conductor for contaminants and, thus, their penetration into the internal environment of the body increases, thereby increasing the toxicity of contaminants; - ENMs and contaminants do not interact with each other in any way, therefore the toxicity of each of them is determined only by its quantity and does not depend on the quantity of another component. Authors hypothesized that the degree of adsorption of various elements on the surface of ENMs may be a unique characteristic of their action, allowing a more accurate understanding of the processes occurring in a living organism.

Keywords: absorption, cadmium, engineered nanomaterials, lead

Procedia PDF Downloads 84

Authors: A. M. Isakhanyan, F. N. Tkhruni, N. N. Yakimovich, Z. I. Kuvaeva, T. V. Khachatryan

Abstract:

Introduction: At present, the simbiotics based on different genera and species of lactic acid bacteria (LAB) and yeasts are used. One of the basic properties of probiotics is presence of antimicrobial activity and therefore selection of LAB and yeast strains for their co-cultivation with the aim of increasing of the activity is topical. Since probiotic yeast and bacteria have different mechanisms of action, natural synergies between species, higher viability and increasing of antimicrobial activity might be expected from mixing both types of probiotics. Endemic strains of LAB Enterococcus faecium БТK-64, Lactobaccilus plantarum БТK-66, Pediococcus pentosus БТK-28, Lactobacillus rhamnosus БТK-109 and Kluyveromyces lactis БТX-412, Saccharomycopsis sp. БТX- 151 strains of yeast, with probiotic properties and hight antimicrobial activity, were selected. Strains are deposited in "Microbial Depository Center" (MDC) SPC "Armbiotechnology". Methods: LAB and yeast strains were isolated from different dairy products from rural households of Armenia. The genotyping by 16S rRNA sequencing for LAB and 26S RNA sequencing for yeast were used. Combined cultivation of LAB and yeast strains was carried out in the nutrient media on the basis of milk whey, in anaerobic conditions (without shaker, in a thermostat at 37oC, 48 hours). The complex preparations were obtained by purification of cell free culture broth (CFC) broth by the combination of ion-exchange chromatography and gel filtration methods. The spot-on-lawn method was applied for determination of antimicrobial activity and expressed in arbitrary units (AU/ml). Results. The obtained data showed that at the combined growth of bacteria and yeasts, the cultivation conditions (medium composition, time of growth, genera of LAB and yeasts) affected the display of antimicrobial activity. Purification of CFC broth allowed obtaining partially purified antimicrobial complex preparation which contains metabiotics from both bacteria and yeast. The complex preparation inhibited the growth of pathogenic and conditionally pathogenic bacteria, isolated from various internal organs from diseased animals and poultry with greater efficiency than the preparations derived individually alone from yeast and LAB strains. Discussion. Thus, our data shown perspectives of creation of a new class of antimicrobial preparations on the basis of combined cultivation of endemic strains of LAB and yeast. Obtained results suggest the prospect of use of the partially purified complex preparations instead antibiotics in the agriculture and for food safety. Acknowledgments: This work was supported by the RA MES State Committee of Science and Belarus National Foundation for Basic Research in the frames of the joint Armenian - Belarusian joint research project 13РБ-064.

Keywords: co-cultivation, antimicrobial activity, biosafety, metabiotics, lactic acid bacteria, yeast

Procedia PDF Downloads 332

Authors: Richard Sogah

Abstract:

The significance of transport infrastructure investments for economic growth and development has been central to the World Bank’s strategy for poverty reduction. Among the conventional surface transport infrastructures, road infrastructure is significant in facilitating the movement of human capital goods and services. When transport projects (i.e., roads, super-highways) are implemented, they come along with some negative social values (costs), such as increased noise and air pollution for local residents living near these facilities, displaced individuals, etc. However, these projects also facilitate better utilization of existing capital stock and generate other observable benefits that can be easily quantified. For example, the improvement or construction of roads creates employment, stimulates revenue generation (toll), reduces vehicle operating costs and accidents, increases accessibility, trade expansion, safety improvement, etc. Aside from these benefits, travel time savings (TTSs) which are the major economic benefits of urban and inter-urban transport projects and therefore integral in the economic assessment of transport projects, are often overlooked and omitted when estimating the benefits of transport projects, especially in developing countries. The absence of current and reliable domestic travel data and the inability of replicated models from the developed world to capture the actual value of travel time savings due to the large unemployment, underemployment, and other labor-induced distortions has contributed to the failure to assign value to travel time savings when estimating the benefits of transport schemes in developing countries. This omission of the value of travel time savings from the benefits of transport projects in developing countries poses problems for investors and stakeholders to either accept or dismiss projects based on schemes that favor reduced vehicular operating costs and other parameters rather than those that ease congestion, increase average speed, facilitate walking and handloading, and thus save travel time. Given the complex reality in the estimation of the value of travel time savings and the presence of widespread informal labour activities in Sub-Saharan Africa, we construct a “nationally ranked distribution of time values” and estimate the value of travel time savings based on the area beneath the distribution. Compared with other approaches, our method captures both formal sector workers and individuals/people who work outside the formal sector and hence changes in their time allocation occur in the informal economy and household production activities. The dataset for the estimations is sourced from the World Bank, the International Labour Organization, etc.

Keywords: road infrastructure, transport projects, travel time savings, congestion, Sub-Sahara Africa

Procedia PDF Downloads 101

Authors: Angela Cristina Da F. De Oliveira, Salma E. Asmar, Norbert P. Battlori, Yaz Vera, Uriel R. Valencia, Tâmara D. Borges, Antoni D. Bueno, Leandro B. Costa

Abstract:

The present study aimed to evaluate the replacement of 5% of starch per 5% of sunflower oil (SO) on meat quality and animal welfare of growing and finishing pigs (Iberic x Duroc), exposed to a heat stress environment. The experiment lasted 90 days, and it was carried out in a randomized block design, in a 2 x 2 factorial, composed of two diets (starch or sunflower oil (with or without) and two feed intake management (ad libitum and restriction). Seventy-two crossbred males (51± 6,29 kg body weight - BW) were housed in climate-controlled rooms, in collective pens and exposed to heat stress environment (32°C; 35% to 50% humidity). The treatments studies were: 1) control diet (5% starch x 0% SO) with ad libitum intake (n = 18); 2) SO diet (replacement of 5% of starch per 5% of SO) with ad libitum intake (n = 18); 3) control diet with restriction feed intake (n = 18); or 4) SO diet with restriction feed intake (n = 18). Feed were provided in two phases, 50-100 Kg BW for growing and 100-140 Kg BW for finishing, respectively. Within welfare evaluations, dirtiness score was evaluated all morning during ninety days of the experiment. The presence of manure was individually measured based on one side of the pig´s body and scored according to: 0 (less than 20% of the body surface); 1 (more than 20% but less than 50% of the body surface); 2 (over 50% of the body surface). After the experimental period, when animals reach 130-140 kg BW, they were slaughtered using carbon dioxide (CO2) stunning. Carcass weight, leanness and fat content, measured at the last rib, were recorded within 20 min post-mortem (PM). At 24h PM, pH, electrical conductivity and color measures (L, a*, b*) were recorded in the Longissimus thoracis and Semimembranosus muscles. Data shown no interaction between diet (control x SO) and management feed intake (ad libitum x restriction) on the meat quality parameters. Animals in ad libitum management presented an increase (p < 0.05) on BW, carcass weight (CW), back fat thickness (BT), and intramuscular fat content (IM) when compared with animals in restriction management. In contrast, animals in restriction management showing a higher (p < 0.05) carcass yield, percentage of lean and loin thickness. To welfare evaluations, the interaction between diet and management feed intake did not influence the degree of dirtiness. Although, the animals that received SO diet, independently of the management, were cleaner than animals in control group (p < 0,05), which, for pigs, demonstrate an important strategy to reduce body temperature. Based in our results, the diet and management feed intake had a significant influence on meat quality and animal welfare being considered efficient nutritional strategies to reduce heat stress and improved meat quality.

Keywords: dirtiness, environment, meat, pig

Procedia PDF Downloads 257

Authors: Heena Dabas, Anju Paul, Suman Chaurasia, Ramesh Agarwal, M. Jeeva Sankar, Anurag Bajpai, Manju Saksena

Abstract:

Background: Traumatic lumbar puncture (LP) is a common occurrence and causes substantial diagnostic ambiguity. There is paucity of data regarding its epidemiology. Objective: To assess the incidence and risk factors of traumatic LP in newborns. Design/Methods: In a prospective cohort study, all inborn neonates admitted in NICU and planned to undergo LP for a clinical indication of sepsis were included. Neonates with diagnosed intraventricular hemorrhage (IVH) of grade III and IV were excluded. The LP was done by operator - often a fellow or resident assisted by bedside nurse. The unit has policy of not routinely using any sedation/analgesia during the procedure. LP is done by 26 G and 0.5-inch-long hypodermic needle inserted in third or fourth lumbar space while the infant is in lateral position. The infants were monitored clinically and by continuous measurement of vital parameters using multipara monitor during the procedure. The occurrence of traumatic tap along with CSF parameters and other operator and assistant characteristics were recorded at the time of procedure. Traumatic tap was defined as presence of visible blood or more than 500 red blood cells on microscopic examination. Microscopic trauma was defined when CSF is not having visible blood but numerous RBCs. The institutional ethics committee approved the study protocol. A written informed consent from the parents and the health care providers involved was obtained. Neonates were followed up till discharge/death and final diagnosis was assigned along with treating team. Results: A total of 362 (21%) neonates out of 1726 born at the hospital were admitted during the study period (July 2016 to January, 2017). Among these neonates, 97 (26.7%) were suspected of sepsis. A total of 54 neonates were enrolled who met the eligibility criteria and parents consented to participate in the study. The mean (SD) birthweight was 1536 (732) grams and gestational age 32.0 (4.0) weeks. All LPs were indicated for late onset sepsis at the median (IQR) age of 12 (5-39) days. The traumatic LP occurred in 19 neonates (35.1%; 95% C.I 22.6% to 49.3%). Frank blood was observed in 7 (36.8%) and in the remaining, 12(63.1%) CSF was detected to have microscopic trauma. The preliminary risk factor analysis including birth weight, gestational age and operator/assistant and other characteristics did not demonstrate clinically relevant predictors. Conclusion: A significant number of neonates requiring lumbar puncture in our study had high incidence of traumatic tap. We were not able to identify modifiable risk factors. There is a need to understand the reasons and further reduce this issue for improving management in NICUs.

Keywords: incidence, newborn, traumatic, lumbar puncture

Procedia PDF Downloads 290

Authors: Aneeqa Suhail, Shabana Naveed

Abstract:

The public sector (in both developed and developing countries) has gone through various waves of radical reforms in recent decades. In Pakistan, under the influence of New Public Management(NPM) Reforms; best practices of private sector are introduced in the public sector to modernize public organizations. Human Resource Information System (HRIS) has been popular in the private sector and proven to be a successful system, therefore it is being adopted in the public sector too. However, implementation of private business practices in public organizations us very challenging due to differences in context. This implementation gets further critical in Pakistan due to a centralizing tendency and lack of autonomy in public organizations. Adoption of HRIS by public organizations in Pakistan raises several questions: What challenges are faced by public organizations in implementation of HRIS? Are benefits of HRIS such as efficiency, process integration and cost reduction achieved? How is the previous system improved with this change and what are the impacts? Yet, it is an under-researched topic, especially in public enterprises. This study contributes to the existing body of knowledge by empirically exploring benefits and challenges of implementation of HRIS in public organizations. The research adopts a case study approach and uses qualitative data based on in-depth interviews conducted at various levels in the hierarchy including top management, departmental heads and employees. The unit of analysis is LESCO, the Lahore Electric Supply Company, a state-owned entity that generates, transmits and distributes electricity to 4 big cities in Punjab, Pakistan. The findings of the study show that LESCO has not achieved the benefits of HRIS as established in literature. The implementation process remained quite slow and costly. Various functions of HR are still in isolation and integration is a big challenge for the organization. Although the data is automated, the previous system of manually record maintenance and paperwork is still in work, resulting in the presence of parallel practices. The findings also identified resistance to change from top management and labor workforce, lack of commitment and technical knowledge, and costly vendors as major barriers that affect the effective implementation of HRIS. The paper suggests some potential actions to overcome these barriers and to enhance effective implementation of HR-technology. The findings are explained in light of an institutional logics perspective. HRIS’ new logic of automated and integrated HR system is in sharp contrast with the prevailing logic of process-oriented manual data maintenance, leading to resistance to change and deadlock.

Keywords: human resource information system, technological changes, state-owned enterprise, implementation challenges

Procedia PDF Downloads 142

Authors: Mohamed Adel Ahmed, Warda Youssef Morsy , Hanaa Ali El Feky

Abstract:

Background: Literature review cited that sleep is absolutely essential for surviving and reclamation of the quality of life. Critically ill patients often have poor sleep quality with prolonged sleep latency, sleep fragmentation, decreased sleep efficiency and frequent arousals. Nurses have a unique role for the early diagnosis of sleep disorders, decreasing stressors levels and providing the necessary environmental regulations to create a therapeutic ambiance. The aim of the study: to assess perceived sleep quality and identify factors affecting sleep quality among adult critically ill patients At El Manial University Hospital. Research Design: A descriptive exploratory design was utilized. Research questions: a) how do adult critically ill patients perceive sleep quality in the Critical Care Department of El Manial University Hospital? b) What are the factors affecting sleep quality among adult critically ill patients at El Manial University Hospital? Setting: selected critical and cardiac care units at El Manial University Hospital. Sample: A samples of convenience consisting of 100 adult male and female patients were included in the study. Tools of data collection: tool 1: Socio-demographic and Medical Data Sheet, tool 2: Modified St Mary's Hospital Sleep Questionnaire tool 3: Factors Affecting Sleep Quality Questionnaire among ICU Patients Results: The current study revealed that 76.0% of the studied sample had lack of sleep disturbance before hospitalization. However, 84 % had sleep disturbances during ICU stay, of these more than two-thirds (67 %) had moderate sleep disturbance. Presence of strange and bad odors, noise, having pain, fear of death and a loud voice produced by the ICU personnel had the most significant negative impact on patients’ sleep in percentage of 52.4, 50, 61.9, 45.2, 52.4, respectively. Conclusion: Sleep disturbances in the ICU are multifactorial, and ICU patients’ perceived degrees of sleep disturbance as a moderate. Recommendations: Based on findings of the present study, the following are recommended to be done by ICU nurses; create a healing ICU environment that should incorporate noise, light and temperature controls; decrease stimuli during night time hours to promote regulation of the circadian rhythm, allow usage of sleeping aids such as relaxing music, eye patches and earplugs into their daily nursing practice; cluster nursing activities and eliminate non-essential treatments during night time hours to allow uninterrupted sleep periods of at least 90 minutes to complete one sleep cycle , and minimize staff conversation, alarm noise and light during the quiet night time hours.

Keywords: sleep quality, critically ill, patients, perception

Procedia PDF Downloads 438

Authors: Norazlan Mohmad Misnan, Maizatul Hasyima Omar, Mohd Isa Wasiman

Abstract:

Papaya (Carica papaya L., Caricaceae) is a tree which mainly cultivated for its fruits in many tropical regions including Australia, Brazil, China, Hawaii, and Malaysia. Beside of fruits, its leaves, seeds, and latex have also been traditionally used for treating diseases, which also reported to possess anti-cancer and anti- malaria properties. Its leaves have been reported to consist of various chemical compounds such as alkaloids, flavonoids and phenolics. Clitorin and manghaslin are among major flavonoids presence. Thus, the aim of this study is to quantify the purity of these isolated compounds (clitorin and manghsalin) by using quantitative Nuclear Magnetic Resonance (qNMR) analysis. Only fresh C. papaya leaves were used for juice extraction procedure and subsequently was freeze-dried to obtain a dark green powdered form of the extract prior to Centrifugal Partition Chromatography (CPC) separation. The CPC experiments were performed using a two-phase solvent system comprising ethyl acetate/butanol/water (1:4:5, v/v/v/v) solvent. The upper organic phase was used as the stationary phase, and the lower aqueous phase was employed as the mobile phase. Ten fractions were obtained after an hour runtime analysis. Fraction 6 and fraction 8 has been identified as clitorin (m/z 739.21 [M-H]-) and manghaslin (m/z 755.21 [M-H]-), respectively, based on LCMS data and full analysis of NMR (1H NMR, 13C NMR, HMBC, and HSQC). The 1H-qNMR measurements were carried out using a 400 MHz NMR spectrometer (JEOL ECS 400MHz, Japan) and deuterated methanol was used as a solvent. Quantification was performed using the AQARI method (Accurate Quantitative NMR) with deuterated 1,4-Bis(trimethylsilyl)benzene (BTMSB) as an internal reference substances. This AQARI protocol includes not only NMR measurement but also sample preparation that provide highest precision and accuracy than other qNMR methods. The 90° pulse length and the T1 relaxation times for compounds and BTMSB were determined prior to the quantification to give the best signal-to-noise ratio. Regions containing the two downfield signals from aromatic part (6.00–6.89 ppm), and the singlet signal, (18H) arising from BTMSB (0.63-1.05ppm) were selected for integration. The purity of clitorin and manghaslin were calculated to be 52.22% and 43.36%, respectively. Further purification is needed in order to increase its purity. This finding has demonstrated the use of qNMR for quality control and standardization of various plant extracts and which can be applied for NMR fingerprinting of other plant-based products with good reproducibility and in the case where commercial standards is not readily available.

Keywords: Carica papaya, clitorin, manghaslin, quantitative Nuclear Magnetic Resonance, Centrifugal Partition Chromatography

Procedia PDF Downloads 488

Authors: Kuheli Chakrabarty, Animesh Ghosh, Atanu Roy, Gourab Kanti Das

Abstract:

Aldol reaction is an important class of carbon-carbon bond forming reactions. One of the popular ways to impose asymmetry in aldol reaction is the introduction of chiral auxiliary that binds the approaching reactants and create dissymmetry in the reaction environment, which finally evolves to enantiomeric excess in the aldol products. The last decade witnesses the usage of natural amino acids as chiral auxiliary to control the stereoselectivity in various carbon-carbon bond forming processes. In this context, L-proline was found to be an effective organocatalyst in asymmetric aldol additions. In last few decades the use of water as solvent or co-solvent in asymmetric organocatalytic reaction is increased sharply. Simple amino acids like L-proline does not catalyze asymmetric aldol reaction in aqueous medium not only that, In organic solvent medium high catalytic loading (~30 mol%) is required to achieve moderate to high asymmetric induction. In this context, huge efforts have been made to modify L-proline and 4-hydroxy-L-proline to prepare organocatalyst for aqueous medium asymmetric aldol reaction. Here, we report the result of our DFT calculations on asymmetric aldol reaction of benzaldehyde, p-NO2 benzaldehyde and t-butyraldehyde with a number of ketones using L-proline hydrazide as organocatalyst in wet solvent free condition. Gaussian 09 program package and Gauss View program were used for the present work. Geometry optimizations were performed using B3LYP hybrid functional and 6-31G(d,p) basis set. Transition structures were confirmed by hessian calculation and IRC calculation. As the reactions were carried out in solvent free condition, No solvent effect were studied theoretically. Present study has revealed for the first time, the direct involvement of two water molecules in the aldol transition structures. In the TS, the enamine and the aldehyde is connected through hydrogen bonding by the assistance of two intervening water molecules forming a supramolecular network. Formation of this type of supramolecular assembly is possible due to the presence of protonated -NH2 group in the L-proline hydrazide moiety, which is responsible for the favorable entropy contribution to the aldol reaction. It is also revealed from the present study that, water assisted TS is energetically more favorable than the TS without involving any water molecule. It can be concluded from this study that, insertion of polar group capable of hydrogen bond formation in the L-proline skeleton can lead to a favorable aldol reaction with significantly high enantiomeric excess in wet solvent free condition by reducing the activation barrier of this reaction.

Keywords: aldol reaction, DFT, organocatalysis, transition structure

Procedia PDF Downloads 429

Authors: Tatyana Savchuk, Yelena Grinvald, Mohamed Ali, Ramune Sepetiene, Dinara Sadvakassova, Saniya Saussakova, Kuralay Zhangazieva, Dulat Imashpayev

Abstract:

Introduction. The problem of viral hepatitis B (HBV) takes a vital place in the global health system. The existing risk of HBV transmission through blood transfusions is associated with transfusion of blood taken from infected individuals during the “serological window” period or from patients with latent HBV infection, the marker of which is anti-HBcore. In the absence of information about other markers of hepatitis B, the presence of anti-HBcore suggests that a person may be actively infected or has suffered hepatitis B in the past and has immunity. Aim. To study the risk factors influencing the positive anti-HBcore indicators among the donor population. Materials and Methods. The study was conducted in 2021 in the Scientific and Production Center of Transfusiology of the Ministry of Healthcare in Kazakhstan. The samples taken from blood donors were tested for anti-HBcore, by CLIA on the Architect i2000SR (ABBOTT). A special questionnaire was developed for the blood donors’ socio-demographic characteristics. Statistical analysis was conducted by the R software (version 4.1.1, USA, 2021). Results.5709 people aged 18 to 66 years were included in the study, the proportion of men and women was 68.17% and 31.83%, respectively. The average age of the participants was 35.7 years. A weighted multivariable mixed effects logistic regression analysis showed that age (p<0.001), ethnicity (p<0.05), and marital status (p<0.05) were statistically associated with anti-HBcore positivity. In particular, analysis adjusting for gender, nationality, education, marital status, family history of hepatitis, blood transfusion, injections, and surgical interventions, with a one-year increase in age (adjOR=1.06, 95%CI:1.05-1.07), showed an 6% growth in odds of having anti-HBcore positive results. Those who were russian ethnicity (adjOR=0.65, 95%CI:0.46-0.93) and representatives of other nationality groups (adjOR=0.56, 95%CI:0.37-0.85) had lower odds of having anti-HBcore when compared to Kazakhs when controlling for other covariant variables. Among singles, the odds of having a positive anti-HBcore were lower by 29% (adjOR = 0.71, 95%CI:0.57-0.89) compared to married participants when adjusting for other variables. Conclusions.Kazakhstan is one of the countries with medium endemicity of HBV prevalence (2%-7%). Results of the study demonstrated the possibility to form a profile of risk factors (age, nationality, marital status). Taking into account the data, it is recommended to increase attention to donor questionnaires by adding leading questions and to improve preventive measures to prevent HBV. Funding. This research was supported by a grant from Abbott Laboratories.

Keywords: anti-HBcore, blood donor, donation, hepatitis B virus, occult hepatitis

Procedia PDF Downloads 100

Authors: Arsalan Jabbar, Wajiha Javed, Nelofer Mehboob, Zahid Memon

Abstract:

Introduction: There are multiple social, individual and cultural factors that influence an individual’s decision to adopt family planning methods especially among non-users in patriarchal societies like Pakistan.Non-users, if targeted efficiently, can contribute significantly to country’s CPR. A research study showed that non-users if convinced to adopt lactational amenorrhea method can shift to long-term methods in future. Research shows that if non-users are targeted efficiently a 59% reduction in unintended pregnancies in Saharan Africa and South-Central and South-East Asia is anticipated. Methods: We did secondary data analysis on Pakistan Demographic Heath Survey (2012-13) dataset. Use of contraception (never-use/ever-use) was the outcome variable. At univariate level Chi-square/Fisher Exact test was used to assess relationship of baseline covariates with contraception use. Then variables to be incorporated in the model were checked for multi-collinearity, confounding, and interaction. Then binary logistic regression (with an urban-rural stratification) was done to find the relationship between contraception use and baseline demographic and social variables. Results: The multivariate analyses of the study showed that younger women (≤ 29 years) were more prone to be never users as compared to those who were > 30 years and this trend was seen in urban areas (AOR 1.92, CI 1.453-2.536) as well as rural areas (AOR 1.809, CI 1.421-2.303). While looking at regional variation, women from urban Sindh (AOR 1.548, CI 1.142-2.099) and urban Balochistan (AOR 2.403, CI 1.504-3.839) had more never users as compared to other urban regions. Women in the rich wealth quintile were more never users and this was seen both in urban and rural localities (urban (AOR 1.106 CI .753-1.624); rural areas (AOR 1.162, CI .887-1.524)) even though these were not statistically significant. Women idealizing more children(> 4) are more never users as compared to those idealizing less children in both urban (AOR 1.854, CI 1.275-2.697) and rural areas (AOR 2.101, CI 1.514-2.916). Women who never lost a pregnancy were more inclined to be non-users in rural areas (AOR 1.394, CI 1.127-1.723) .Women familiar with only traditional or no method had more never users in rural areas (AOR 1.717, CI 1.127-1.723) but in urban areas it wasn’t significant. Women unaware of Lady Health Worker’s presence in their area were more never users especially in rural areas (AOR 1.276, CI 1.014-1.607). Women who did not visit any care provider were more never users (urban (AOR 11.738, CI 9.112-15.121) rural areas (AOR 7.832, CI 6.243-9.826)). Discussion/Conclusion: This study concluded that government, policy makers and private sector family planning programs should focus on the untapped pool of never users (younger women from underserved provinces, in higher wealth quintiles, who desire more children.). We need to make sure to cover catchment areas where there are less LHWs and less providers as ignorance to modern methods and never been visited by an LHW are important determinants of never use. This all is in sync with previous literate from similar developing countries.

Keywords: contraception, demographic and health survey, family planning, never users

Procedia PDF Downloads 403

Authors: Angela T. H. Kwan, Wenjun Liang, Jack Wellington, Mohammad Mofatteh, Thanh N. Nguyen, Pingzhong Fu, Juanmei Chen, Zile Yan, Weijuan Wu, Yongting Zhou, Shuiquan Yang, Sijie Zhou, Yimin Chen

Abstract:

Background: Endovascular Therapy (EVT)—in the form of mechanical thrombectomy—following intravenous thrombolysis is the standard gold treatment for patients with acute ischemic stroke (AIS) due to large vessel occlusion (LVO). It is well established that an ASPECTS ≥ 7 is associated with an increased likelihood of positive post-EVT outcomes, as compared to an ASPECTS < 7. There is also prognostic utility in coupling posterior circulation ASPECTS (pc-ASPECTS) with magnetic resonance imaging for evaluating the post-EVT functional outcome. However, the value of pc-ASPECTS applied to CT must be explored further to determine its usefulness in predicting functional outcomes following EVT. Objective: In this study, we aimed to determine whether pc-ASPECTS on CT can predict post-EVT functional outcomes among patients with AIS due to LVO. Methods: A total of 247 consecutive patients aged 18 and over receiving EVT for LVO-related AIS were recruited into a prospective database. The data were retrospectively analyzed between March 2019 to February 2022 from two comprehensive tertiary care stroke centers: Foshan Sanshui District People’s Hospital and First People's Hospital of Foshan in China. Patient parameters included EVT within 24hrs of symptom onset, premorbid modified Rankin Scale (mRS) ≤ 2, presence of distal and terminal cerebral blood vessel occlusion, and subsequent 24–72-hour post-stroke onset CT scan. Univariate comparisons were performed using the Fisher exact test or χ2 test for categorical variables and the Mann–Whitney U test for continuous variables. A p-value of ≤ 0.05 was statistically significant. Results: A total of 247 patients met the inclusion criteria; however, 3 were excluded due to the absence of post-CTs and 8 for pre-EVT ASPECTS < 7. Overall, 236 individuals were examined: 196 anterior circulation ischemic strokes and 40 posterior strokes of basilar artery occlusion. We found that both baseline post- and pc-ASPECTS ≥ 7 serve as strong positive markers of favorable outcomes at 90 days post-EVT. Moreover, lower rates of inpatient mortality/hospice discharge, 90-day mortality, and 90-day poor outcome were observed. Moreover, patients in the post-ASPECTS ≥ 7 anterior circulation group had shorter door-to-recanalization time (DRT), puncture-to-recanalization time (PRT), and last known normal-to-puncture-time (LKNPT). Conclusion: Patients of anterior and posterior circulation ischemic strokes with baseline post- and pc-ASPECTS ≥ 7 may benefit from EVT.

Keywords: endovascular therapy, thrombectomy, large vessel occlusion, cerebral ischemic stroke, ASPECTS

Procedia PDF Downloads 101

Authors: Stefano Iannello, Massimiliano Materazzi

Abstract:

Fluidized bed reactor technologies are one of the most valuable pathways for thermochemical conversions of biogenic fuels due to their good operating flexibility. Nevertheless, there are still issues related to the mixing and separation of heterogeneous phases during operation with highly volatile feedstocks, including biomass and waste. At high temperatures, the volatile content of the feedstock is released in the form of the so-called endogenous bubbles, which generally exert a “lift” effect on the particle itself by dragging it up to the bed surface. Such phenomenon leads to high release of volatile matter into the freeboard and limited mass and heat transfer with particles of the bed inventory. The aim of this work is to get a better understanding of the behaviour of a single reacting particle in a hot fluidized bed reactor during the devolatilization stage. The analysis has been undertaken at different fluidization regimes and temperatures to closely mirror the operating conditions of waste-to-energy processes. Beechwood and polypropylene particles were used to resemble the biomass and plastic fractions present in waste materials, respectively. The non-invasive X-ray technique was coupled to particle tracking algorithms to characterize the motion of a single feedstock particle during the devolatilization with high resolution. A high-energy X-ray beam passes through the vessel where absorption occurs, depending on the distribution and amount of solids and fluids along the beam path. A high-speed video camera is synchronised to the beam and provides frame-by-frame imaging of the flow patterns of fluids and solids within the fluidized bed up to 72 fps (frames per second). A comprehensive mathematical model has been developed in order to validate the experimental results. Beech wood and polypropylene particles have shown a very different dynamic behaviour during the pyrolysis stage. When the feedstock is fed from the bottom, the plastic material tends to spend more time within the bed than the biomass. This behaviour can be attributed to the presence of the endogenous bubbles, which drag effect is more pronounced during the devolatilization of biomass, resulting in a lower residence time of the particle within the bed. At the typical operating temperatures of thermochemical conversions, the synthetic polymer softens and melts, and the bed particles attach on its outer surface, generating a wet plastic-sand agglomerate. Consequently, this additional layer of sand may hinder the rapid evolution of volatiles in the form of endogenous bubbles, and therefore the establishment of a poor drag effect acting on the feedstock itself. Information about the mixing and segregation of solid feedstock is of prime importance for the design and development of more efficient industrial-scale operations.

Keywords: fluidized bed, pyrolysis, waste feedstock, X-ray

Procedia PDF Downloads 166

Authors: A. M. Tarola, R. Preti, A. M. Girelli, P. Campana

Abstract:

Goat dairy products are gaining popularity worldwide. In developing countries, but also in many marginal regions of the Mediterranean area, goats represent a great part of the economy and ensure food security. In fact, these small ruminants are able to convert efficiently poor weedy plants and small trees into traditional products of high nutritional quality, showing great resilience to different climatic and environmental conditions. In developed countries, goat milk is appreciated for the presence of health-promoting compounds, bioactive compounds such as conjugated linoleic acids, oligosaccharides, sphingolipids and polyammines. This paper focuses on the recent advances in literature on the nutritional properties of goat milk and on innovative techniques to improve its quality as to become a promising functional food. The environmental sustainability of different methodologies of production has also been examined. Goat milk is valued today as a food of high nutritional value and functional properties as well as small environmental footprint. It is widely consumed in many countries due to high nutritional value, lower allergenic potential, and better digestibility when compared to bovine milk, that makes this product suitable for infants, elderly or sensitive patients. The main differences in chemical composition between a cow and goat milk rely on fat globules that in goat milk are smaller and in fatty acids that present a smaller chain length, while protein, fat, and lactose concentration are comparable. Milk nutritional properties have demonstrated to be strongly influenced by animal diet, genotype, and welfare, but also by season and production systems. Furthermore, there is a growing interest in the dairy industry in goat milk for its relatively high concentration of prebiotics and a good amount of probiotics, which have recently gained importance for their therapeutic potential. Therefore, goat milk is studied as a promising matrix to develop innovative functional foods. In addition to the economic and nutritional value, goat milk is considered a sustainable product for its small environmental footprint, as they require relatively little water and land, and less medical treatments, compared to cow, these characteristics make its production naturally vocated to organic farming. Organic goat milk production has becoming more and more interesting both for farmers and consumers as it can answer to several concerns like environment protection, animal welfare and economical sustainment of rural populations living in marginal lands. These evidences make goat milk an ancient food with novel properties and advantages to be valorized and exploited.

Keywords: goat milk, nutritional quality, bioactive compounds, sustainable production, animal welfare

Procedia PDF Downloads 145

Authors: N. Demertzis, J. L. Bowen

Abstract:

Sepsis is a complex and rapidly evolving condition, resulting from uncontrolled prolonged activation of host immune system due to pathogenic insult. The aim of this study is the development of a multiplex electrochemical sensing platform, capable of detecting both pathogen associated and host immune markers to enable the rapid and definitive diagnosis of sepsis. A combination of aptamers and molecular imprinting approaches have been employed to generate sensing systems for lipopolysaccharide (LPS), c-reactive protein (CRP) and procalcitonin (PCT). Gold working electrodes were mechanically polished and electrochemically cleaned with 0.1 M sulphuric acid using cyclic voltammetry (CV). Following activation, a self-assembled monolayer (SAM) was generated, by incubating the electrodes with a thiolated anti-LPS aptamer / dithiodibutiric acid (DTBA) mixture (1:20). 3-aminophenylboronic acid (3-APBA) in combination with the anti-LPS aptamer was used for the development of the hybrid molecularly imprinted sensor (apta-MIP). Aptasensors, targeting PCT and CRP were also fabricated, following the same approach as in the case of LPS, with mercaptohexanol (MCH) replacing DTBA. In the case of the CRP aptasensor, the SAM was formed following incubation of a 1:1 aptamer: MCH mixture. However, in the case of PCT, the SAM was formed with the aptamer itself, with subsequent backfilling with 1 μM MCH. The binding performance of all systems has been evaluated using electrochemical impedance spectroscopy. The apta-MIP’s polymer thickness is controlled by varying the number of electropolymerisation cycles. In the ideal number of polymerisation cycles, the polymer must cover the electrode surface and create a binding pocket around LPS and its aptamer binding site. Less polymerisation cycles will create a hybrid system which resembles an aptasensor, while more cycles will be able to cover the complex and demonstrate a bulk polymer-like behaviour. Both aptasensor and apta-MIP were challenged with LPS and compared to conventional imprinted (absence of aptamer from the binding site, polymer formed in presence of LPS) and non-imprinted polymers (NIPS, absence of LPS whilst hybrid polymer is formed). A stable LPS aptasensor, capable of detecting down to 5 pg/ml of LPS was generated. The apparent Kd of the system was estimated at 17 pM, with a Bmax of approximately 50 pM. The aptasensor demonstrated high specificity to LPS. The apta-MIP demonstrated superior recognition properties with a limit of detection of 1 fg/ml and a Bmax of 100 pg/ml. The CRP and PCT aptasensors were both able to detect down to 5 pg/ml. Whilst full binding performance is currently being evaluated, there is none of the sensors demonstrate cross-reactivity towards LPS, CRP or PCT. In conclusion, stable aptasensors capable of detecting LPS, PCT and CRP at low concentrations have been generated. The realisation of a multiplex panel such as described herein, will effectively contribute to the rapid, personalised diagnosis of sepsis.

Keywords: aptamer, electrochemical impedance spectroscopy, molecularly imprinted polymers, sepsis

Procedia PDF Downloads 122

Authors: Maksudur Rahman Khan, Kar Min Chan, Huei Ruey Ong, Chin Kui Cheng, Wasikur Rahman

Abstract:

Microbial fuel cells (MFCs) represent a promising technology for simultaneous bioelectricity generation and wastewater treatment. Catalysts are significant portions of the cost of microbial fuel cell cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. The sluggish oxygen reduction reaction (ORR) rate at air cathode necessitates efficient electrocatalyst such as carbon supported platinum catalyst (Pt/C) which is very costly. Manganese oxide (MnO2) was a representative metal oxide which has been studied as a promising alternative electrocatalyst for ORR and has been tested in air-cathode MFCs. However, the single MnO2 has poor electric conductivity and low stability. In the present work, the MnO2 catalyst has been modified by doping Pt nanoparticle. The goal of the work was to improve the performance of the MFC with minimum Pt loading. MnO2 and Pt nanoparticles were prepared by hydrothermal and sol-gel methods, respectively. Wet impregnation method was used to synthesize Pt/MnO2 catalyst. The catalysts were further used as cathode catalysts in air-cathode cubic MFCs, in which anaerobic sludge was inoculated as biocatalysts and palm oil mill effluent (POME) was used as the substrate in the anode chamber. The as-prepared Pt/MnO2 was characterized comprehensively through field emission scanning electron microscope (FESEM), X-Ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and cyclic voltammetry (CV) where its surface morphology, crystallinity, oxidation state and electrochemical activity were examined, respectively. XPS revealed Mn (IV) oxidation state and Pt (0) nanoparticle metal, indicating the presence of MnO2 and Pt. Morphology of Pt/MnO2 observed from FESEM shows that the doping of Pt did not cause change in needle-like shape of MnO2 which provides large contacting surface area. The electrochemical active area of the Pt/MnO2 catalysts has been increased from 276 to 617 m2/g with the increase in Pt loading from 0.2 to 0.8 wt%. The CV results in O2 saturated neutral Na2SO4 solution showed that MnO2 and Pt/MnO2 catalysts could catalyze ORR with different catalytic activities. MFC with Pt/MnO2 (0.4 wt% Pt) as air cathode catalyst generates a maximum power density of 165 mW/m3, which is higher than that of MFC with MnO2 catalyst (95 mW/m3). The open circuit voltage (OCV) of the MFC operated with MnO2 cathode gradually decreased during 14 days of operation, whereas the MFC with Pt/MnO2 cathode remained almost constant throughout the operation suggesting the higher stability of the Pt/MnO2 catalyst. Therefore, Pt/MnO2 with 0.4 wt% Pt successfully demonstrated as an efficient and low cost electrocatalyst for ORR in air cathode MFC with higher electrochemical activity, stability and hence enhanced performance.

Keywords: microbial fuel cell, oxygen reduction reaction, Pt/MnO2, palm oil mill effluent, polarization curve

Procedia PDF Downloads 550

Authors: Olena Kavats, Dmitry Khramov, Kateryna Sergieieva, Vladimir Vasyliev, Iurii Kavats

Abstract:

Geoinformation technologies of space agromonitoring are a means of operative decision making support in the tasks of managing the agricultural sector of the economy. Existing technologies use satellite images in the optical range of electromagnetic spectrum. Time series of optical images often contain gaps due to the presence of clouds and haze. A geoinformation technology is created. It allows to fill gaps in time series of optical images (Sentinel-2, Landsat-8, PROBA-V, MODIS) with radar survey data (Sentinel-1) and use information about agrometeorological conditions of the growing season for individual monitoring years. The technology allows to perform crop classification and mapping for spring-summer (winter and spring crops) and autumn-winter (winter crops) periods of vegetation, monitoring the dynamics of crop state seasonal changes, crop yield forecasting. Crop classification is based on supervised classification algorithms, takes into account the peculiarities of crop growth at different vegetation stages (dates of sowing, emergence, active vegetation, and harvesting) and agriculture land state characteristics (row spacing, seedling density, etc.). A catalog of samples of the main agricultural crops (Ukraine) is created and crop spectral signatures are calculated with the preliminary removal of row spacing, cloud cover, and cloud shadows in order to construct time series of crop growth characteristics. The obtained data is used in grain crop growth tracking and in timely detection of growth trends deviations from reference samples of a given crop for a selected date. Statistical models of crop yield forecast are created in the forms of linear and nonlinear interconnections between crop yield indicators and crop state characteristics (temperature, precipitation, vegetation indices, etc.). Predicted values of grain crop yield are evaluated with an accuracy up to 95%. The developed technology was used for agricultural areas monitoring in a number of Great Britain and Ukraine regions using EOS Crop Monitoring Platform (https://crop-monitoring.eos.com). The obtained results allow to conclude that joint use of Sentinel-1 and Sentinel-2 images improve separation of winter crops (rapeseed, wheat, barley) in the early stages of vegetation (October-December). It allows to separate successfully the soybean, corn, and sunflower sowing areas that are quite similar in their spectral characteristics.

Keywords: geoinformation technology, crop classification, crop yield prediction, agricultural monitoring, EOS Crop Monitoring Platform

Procedia PDF Downloads 447

Authors: Dmitry Kukushkin

Abstract:

Lineaments form complex grids on Earth's surface. Currently, one particular object of study for many researchers is the analysis and geological interpretation of maps of lineament density in an attempt to locate various geological structures. But lineament grids are made up of global, regional and local components, and this superimposition of lineament grids of various scales (global, regional, and local) renders this method less effective. Besides, the erosion processes and the erosional resistance of rocks lying on the surface play a significant role in the formation of lineament grids. Therefore, specific lineament density map is characterized by poor contrast (most anomalies do not exceed the average values by more than 30%) and unstable relation with local geological structures. Our method allows to confidently determine the location and boundaries of local geological structures that are likely to contain mineral deposits. Maps of the fields of lineament distortion (residual specific density) created by our method are characterized by high contrast with anomalies exceeding the average by upward of 200%, and stable correlation to local geological structures containing mineral deposits. Our method considers a lineament grid as a general lineaments field – surface manifestation of stress and strain fields of Earth associated with geological structures of global, regional and local scales. Each of these structures has its own field of brittle dislocations that appears on the surface of its lineament field. Our method allows singling out local components by suppressing global and regional components of the general lineaments field. The remaining local lineament field is an indicator of local geological structures.The following are some of the examples of the method application: 1. Srednevilyuiskoye gas condensate field (Yakutia) - a direct proof of the effectiveness of methodology; 2. Structure of Astronomy (Taimyr) - confirmed by the seismic survey; 3. Active gold mine of Kadara (Chita Region) – confirmed by geochemistry; 4. Active gold mine of Davenda (Yakutia) - determined the boundaries of the granite massif that controls mineralization; 5. Object, promising to search for hydrocarbons in the north of Algeria - correlated with the results of geological, geochemical and geophysical surveys. For both Kadara and Davenda, the method demonstrated that the intensive anomalies of the local lineament fields are consistent with the geochemical anomalies and indicate the presence of the gold content at commercial levels. Our method of suppression of global and regional components results in isolating a local lineament field. In early stages of a geological exploration for oil and gas, this allows determining boundaries of various geological structures with very high reliability. Therefore, our method allows optimization of placement of seismic profile and exploratory drilling equipment, and this leads to a reduction of costs of prospecting and exploration of deposits, as well as acceleration of its commissioning.

Keywords: lineaments, mineral exploration, oil and gas, remote sensing

Procedia PDF Downloads 297

Authors: Temitope L. Baiyegunhi, Christopher Baiyegunhi, Kuiwu Liu, Oswald Gwavava

Abstract:

Diagenesis is the most important factor that affects or impact the reservoir property. Despite the fact that published data gives a vast amount of information on the geology, sedimentology and lithostratigraphy of the Ecca Group in the Karoo Basin of South Africa, little is known of the diagenesis of the potentially feasible shales and sandstones of the Ecca Group. The study aims to provide a general account of the diagenesis of sandstones and mudstone of the Ecca Group. Twenty-five diagenetic textures and structures are identified and grouped into three regimes or stages that include eogenesis, mesogenesis and telogenesis. Clay minerals are the most common cementing materials in the Ecca sandstones and mudstones. Smectite, kaolinite and illite are the major clay minerals that act as pore lining rims and pore-filling cement. Most of the clay minerals and detrital grains were seriously attacked and replaced by calcite. Calcite precipitates locally in pore spaces and partly or completely replaced feldspar and quartz grains, mostly at their margins. Precipitation of cements and formation of pyrite and authigenic minerals as well as little lithification occurred during the eogenesis. This regime was followed by mesogenesis which brought about an increase in tightness of grain packing, loss of pore spaces and thinning of beds due to weight of overlying sediments and selective dissolution of framework grains. Compaction, mineral overgrowths, mineral replacement, clay-mineral authigenesis, deformation and pressure solution structures occurred during mesogenesis. During rocks were uplifted, weathered and unroofed by erosion, this resulted in additional grain fracturing, decementation and oxidation of iron-rich volcanic fragments and ferromagnesian minerals. The rocks of Ecca Group were subjected to moderate-intense mechanical and chemical compaction during its progressive burial. Intergranular pores, matrix micro pores, secondary intragranular, dissolution and fractured pores are the observed pores. The presence of fractured and dissolution pores tend to enhance reservoir quality. However, the isolated nature of the pores makes them unfavourable producers of hydrocarbons, which at best would require stimulation. The understanding of the space and time distribution of diagenetic processes in these rocks will allow the development of predictive models of their quality, which may contribute to the reduction of risks involved in their exploration.

Keywords: diagenesis, reservoir quality, Ecca Group, Karoo Supergroup

Procedia PDF Downloads 142

Authors: Oubelkacem Yacine, El Bast Hassan, El Bakkali Abdelmajid, Lamhasni Taibi, Ettakni Mahmoud, Ait Lyazidi Saadia, Haddad Mustapha, Ben-Ncer Abdelouahed, El Ferrane Mohammed, Boufarra Abdelkrim

Abstract:

The present work relates to an on-site and completely non-invasive investigation of one of the most famous west Mediterranean Torah Scroll housed at the National Library of the Kingdom of Morocco. The scroll is 26 m long and consists of 143 parchment sheets of 59 cm x 19 cm, exhibiting only black writings; it is of unknown age. The artifact has been restored by the curator staff of the library. The investigation exploring separately the parchment support and the writing black ink aims at: i) the examination of the parchment conservation/degradation state, ii) the identification of the black ink and iii) the identification of the parchment handcrafting materials. For this purpose, the analyses have been based on combining all of elemental XRF and structural Raman, ATR-FT Infrared Red and Fiber Optical Reflectance spectroscopies, in addition to chroma-metric and pH measurements. pH measurements showing values around 6.5 are in concordance with the absence of any visual corrosion related to the parchment acidity. However, on the basis of the relative intensities and frequency shift of amid I (AI) and amid II (AII) vibrational bands of the collagen, ATR-FTIR spectra revealed diffuse hydrolysis and gelatinization of the parchment writing support; diffuse and non-homogeny degradation by gelatinization has been also confirmed by the IG gelatinization index deduced from the NIR bands on the FOR spectra. This IG index, defined as the ratio I (6860 cm-1) / I (6685 cm-1), ranges in the interval 0.98 – 1 and highlights collagen degradation at the molecular level. Sequentially Shifted Excitation Raman measurements (SSERS) crossed to X-ray fluorescence (XRF) ones on the black writings revealed that the black ink used is an iron-copper gall one, while FOR spectra are typical of pure metal gall inks. These later reflectance measurements exclude, thus, any intentional addition of carbon black to the ink recipe. Moreover, no lead white had been used while pre-drawing the writing lines. On another side, ATR-FTIR measurements highlighted the presence of oxalates as ink degradation products. Considering the parchment handcrafting, the combination of XRF and ATR-FTIR measurements led to the assumption that this writing support had been prepared according to ancient Middle East practices; the parchment infrared fingerprint seems identical to that of the Dead Sea scroll. The present multi-technical analyses are the first ones performed on an ancient Judaic written parchment of Morocco; it is under furthering. The investigation will be extended to other parchments belonging to the Jewish Cultural Heritage Museum of Morocco in Casablanca.

Keywords: torah scroll, parchment, black ink, non-invasive analyses, XRF/ATR-FTIR/RAMAN/FORS

Procedia PDF Downloads 81

Authors: Mustafa M. Donma, Orkide Donma

Abstract:

Metabolic syndrome (MetS) is a severe health problem which is common among obese individuals. The components of MetS are rather stable in adults compared to the components discussed for children. Due to the ambiguity in this group of the population, how to diagnose MetS in morbid obese (MO) children still constitutes a matter of discussion. For this purpose, a formula, which facilitates the diagnosis of MetS in MO children, was investigated. The aim of this study was to develop a formula which was capable of discriminating MO children with and without MetS findings. Study population comprised MO children. Age and sex-dependent body mass index (BMI) percentiles of the children were above 99. Metabolic syndrome components were also determined. Elevated systolic and diastolic blood pressures (SBP and DBP), elevated fasting blood glucose (FBG), elevated triglycerides (TRG), and/or depressed high density lipoprotein cholesterol (HDL-C) in addition to central obesity were listed as MetS components for each child. Presence of at least two of these components confirmed that the case was MetS. Two groups were constituted. In the first group, there were forty-two MO children without MetS components. Second group was composed of forty-four MO children with at least two MetS components. Anthropometric measurements, including weight, height, waist, and hip circumferences, were performed following physical examination. Body mass index and homeostatic model assessment of insulin resistance values were calculated. Informed consent forms were obtained from the parents of the children. Institutional Non-Interventional Ethics Committee approved the study design. Blood pressure values were recorded. Routine biochemical analysis, including FBG, insulin (INS), TRG, HDL-C were performed. The performance and the clinical utility of the Diagnostic Obesity Notation Model Assessment Metabolic Syndrome Index (DONMA MetS index) [(INS/FBG)/(HDL-C/TRG)*100] was tested. Appropriate statistical tests were applied to the study data. p value smaller than 0.05 was defined as significant. Metabolic syndrome index values were 41.6±5.1 in MO group and 104.4±12.8 in MetS group. Corresponding values for HDL-C values were 54.5±13.2 mg/dl and 44.2±11.5 mg/dl. There were statistically significant differences between the groups (p<0.001). Upon evaluation of the correlations between MetS index and HDL-C values, a much stronger negative correlation was found in MetS group (r=-0.515; p=0.001) in comparison with the correlation detected in MO group (r=-0.371; p=0.016). From these findings, it was concluded that the statistical significance degree of the difference between MO and MetS groups was highly acceptable for this recently introduced MetS index as expected. This was due to the involvement of all of the biochemically defined MetS components into the index. This is particularly important because each of these four parameters used in the formula is cardiac risk factor. Aside from discriminating MO children with and without MetS findings, MetS index introduced in this study is important from the cardiovascular risk point of view in MetS group of children.

Keywords: children, fasting blood glucose, high density lipoprotein cholesterol, index, insulin, metabolic syndrome, morbid obesity, triglycerides.

Procedia PDF Downloads 84

Authors: Jurriaan Gillissen

Abstract:

This work is concerned with stabilizing the numerical integration of the Navier-Stokes equation (NSE), backwards in time. Applications involve the detection of sources of, e.g., sound, heat, and pollutants. Stable reverse numerical integration of parabolic differential equations is also relevant for image de-blurring. While the literature addresses the reverse integration problem of the advection-diffusion equation, the problem of numerical reverse integration of the NSE has, to our knowledge, not yet been addressed. Owing to the presence of viscosity, the NSE is irreversible, i.e., when going backwards in time, the fluid behaves, as if it had a negative viscosity. As an effect, perturbations from the perfect solution, due to round off errors or discretization errors, grow exponentially in time, and reverse integration of the NSE is inherently unstable, regardless of using an implicit time integration scheme. Consequently, some sort of filtering is required, in order to achieve a stable, numerical, reversed integration. The challenge is to find a filter with a minimal adverse affect on the accuracy of the reversed integration. In the present work, we explore an adjoint gradient method (AGM) to achieve this goal, and we apply this technique to two-dimensional (2D), decaying turbulence. The AGM solves for the initial velocity field u0 at t = 0, that, when integrated forward in time, produces a final velocity field u1 at t = 1, that is as close as is feasibly possible to some specified target field v1. The initial field u0 defines a minimum of a cost-functional J, that measures the distance between u1 and v1. In the minimization procedure, the u0 is updated iteratively along the gradient of J w.r.t. u0, where the gradient is obtained by transporting J backwards in time from t = 1 to t = 0, using the adjoint NSE. The AGM thus effectively replaces the backward integration by multiple forward and backward adjoint integrations. Since the viscosity is negative in the adjoint NSE, each step of the AGM is numerically stable. Nevertheless, when applied to turbulence, the AGM develops instabilities, which limit the backward integration to small times. This is due to the exponential divergence of phase space trajectories in turbulent flow, which produces a multitude of local minima in J, when the integration time is large. As an effect, the AGM may select unphysical, noisy initial conditions. In order to improve this situation, we propose two remedies. First, we replace the integration by a sequence of smaller integrations, i.e., we divide the integration time into segments, where in each segment the target field v1 is taken as the initial field u0 from the previous segment. Second, we add an additional term (regularizer) to J, which is proportional to a high-order Laplacian of u0, and which dampens the gradients of u0. We show that suitable values for the segment size and for the regularizer, allow a stable reverse integration of 2D decaying turbulence, with accurate results for more then O(10) turbulent, integral time scales.

Keywords: time reversed integration, parabolic differential equations, adjoint gradient method, two dimensional turbulence

Procedia PDF Downloads 218

Authors: Khrukulu Khusoh

Abstract:

The strategies and tactics used by governments throughout the world to counter terrorism and insurgency over the past few decades include the declaration of states of siege or martial law, enactment of anti-terrorist legislation and strengthening of judicial powers. Some of these measures taken have been more successful than the other, but some have proved counterproductive, alienating the public from the authorities and further polarizing an already fractured political environment. Such cases of alienation and polarization can be seen in the northeastern states of India. The Armed Forces (Special Powers) Act which was introduced to curb insurgency in the remote jungles of the far-flung areas has remained a telling tale of agony in the north east India. Grievous trauma to humans through encounter killings, custodial deaths, unwarranted torture, exploitation of women and children in several ways have been reported in Nagaland, Manipur and other northeastern states where the Indian army has been exercising powers under the Armed Forces (Special Powers) Act. While terrorism and the insurgency are destructive of human rights, counter-terrorism does not necessarily restore and safeguard human rights. This special law has not proven effective particularly in dealing with terrorism and insurgency. The insurgency has persisted in the state of Nagaland even after sixty years notwithstanding the presence of a good number of special laws. There is a need to fight elements that threaten the security of a nation, but the methods chosen should be measured, otherwise the fight is lost. There has been no review on the effectiveness or failure of the act to realize its intended purpose. Nor was there any attempt on the part of the state to critically look at the violation of rights of innocent citizens by the state agencies. The Indian state keeps enacting laws, but none of these could be effectively applied as there was the absence of clarity of purpose. Therefore, every new law which has been enacted time and again to deal with security threats failed to bring any solution for the last six decades. The Indian state resorts to measures which are actually not giving anything in terms of strategic benefits but are short-term victories that might result in long-term tragedies. Therefore, right thinking citizens and human rights activists across the country feel that introduction of Armed Forces (Special Powers) Act was as much violation of human rights and its continuation is undesirable. What worried everyone is the arbitrary use, or rather misuse of power by the Indian armed forces particularly against the weaker sections of the society, including women. After having being subjected to indiscriminate abuse of that law, people of the north-east India have been demanding its revocation for a long time. The present paper attempts to critically examine the violation of human rights under Armed Forces (Special Powers) Act. It also attempts to bring out the impact of Armed Forces (Special Powers) Act on the Naga people.

Keywords: armed forces, insurgency, special laws, violence

Procedia PDF Downloads 488

Authors: Balwinder Singh, Veerpaul Kaur Mann

Abstract:

A composite material is formed by the combination of two or more phases or materials. Natural minerals-derived Basalt fiber is a kind of fiber being introduced in the polymer composite industry due to its good mechanical properties similar to synthetic fibers and low cost, environment friendly. Also, there is a rising trend towards the use of industrial wastes as fillers in polymer composites with the aim of improving the properties of the composites. The mechanical properties of the fiber-reinforced polymer composites are influenced by various factors like fiber length, fiber weight %, filler weight %, filler size, etc. Thus, a detailed study has been done on the characterization of short-chopped Basalt fiber-reinforced polymer matrix composites using fly ash as filler. Taguchi’s L9 orthogonal array has been used to develop the composites by considering fiber length (6, 9 and 12 mm), fiber weight % (25, 30 and 35 %) and filler weight % (0, 5 and 10%) as input parameters with their respective levels and a thorough analysis on the mechanical characteristics (tensile strength and impact strength) has been done using ANOVA analysis with the help of MINITAB14 software. The investigation revealed that fiber weight is the most significant parameter affecting tensile strength, followed by fiber length and fiber weight %, respectively, while impact characterization showed that fiber length is the most significant factor, followed by fly ash weight, respectively. Introduction of fly ash proved to be beneficial in both the characterization with enhanced values upto 5% fly ash weight. The present study on the natural fibres reinforced epoxy composites using fly ash as filler material to study the effect of input parameters on the tensile strength in order to maximize tensile strength of the composites. Fabrication of composites based on Taguchi L9 orthogonal array design of experiments by using three factors fibre type, fibre weight % and fly ash % with three levels of each factor. The Optimization of composition of natural fibre reinforces composites using ANOVA for obtaining maximum tensile strength on fabricated composites revealed that the natural fibres along with fly ash can be successfully used with epoxy resin to prepare polymer matrix composites with good mechanical properties. Paddy- Paddy fibre gives high elasticity to the fibre composite due to presence of approximately hexagonal structure of cellulose present in paddy fibre. Coir- Coir fibre gives less tensile strength than paddy fibre as Coir fibre is brittle in nature when it pulls breakage occurs showing less tensile strength. Banana- Banana fibre has the least tensile strength in comparison to the paddy & coir fibre due to less cellulose content. Higher fibre weight leads to reduction in tensile strength due to increased nuclei of air pockets. Increasing fly ash content reduces tensile strength due to nonbonding of fly ash particles with natural fibre. Fly ash is also not very strong as compared to the epoxy resin leading to reduction in tensile strength.

Keywords: tensile strength and epoxy resin. basalt Fiber, taguchi, polymer matrix, natural fiber

Procedia PDF Downloads 45

Authors: Ammar Boudaka, Maryam Al-Suleimani, Hajar BaOmar, Intisar Al-Lawati, Fahad Zadjali

Abstract:

Background: Hypertension is increasingly becoming a matter of medical and public health importance. The maintenance of normal blood pressure requires a balance between cardiac output and total peripheral resistance. The endothelium, through the release of vasodilating factors, plays an important role in the control of total peripheral resistance and hence blood pressure homeostasis. Transient Receptor Potential Vanilloid type 4 (TRPV4) is a mechanosensitive non-selective cation channel that is expressed on the endothelium and contributes to endothelium-mediated vasodilation. So far, no data are available about the morphological and functional status of this channel in hypertensive cases. Objectives: This study aimed to investigate whether there is any difference in the morphological and functional features of TRPV4 in the mesenteric artery of normotensive and hypertensive rats. Methods: Functional feature of TRPV4 in four experimental animal groups: young and adult Wistar-Kyoto rats (WKY-Y and WKY-A), young and adult spontaneously hypertensive rats (SHR-Y and SHR-A), was studied by adding 5 µM 4αPDD (TRPV4 agonist) to mesenteric arteries mounted in a four-chamber wire myograph and pre-contracted with 4 µM phenylephrine. The 4αPDD-induced response was investigated in the presence and absence of 1 µM HC067047 (TRPV4 antagonist), 100 µM L-NAME (nitric oxide synthase inhibitor), and endothelium. The morphological distribution of TRPV4 in the wall of rat mesenteric arteries was investigated by immunostaining. Real-time PCR was used in order to investigate mRNA expression level of TRPV4 in the mesenteric arteries of the four groups. The collected data were expressed as mean ± S.E.M. with n equal to the number of animals used (one vessel was taken from each rat). To determine the level of significance, statistical comparisons were performed using the student’s t-test and considered to be significantly different at p<0.05. Results: 4αPDD induced a relaxation response in the mesenteric arterial preparations (WKY-Y: 85.98% ± 4.18; n = 5) that was markedly inhibited by HC067047 (18.30% ± 2.86; n= 5; p<0.05), endothelium removal (19.93% ± 1.50; n = 5; p<0.05) and L-NAME (28.18% ± 3.09; n = 5; p<0.05). The 4αPDD-induced relaxation was significantly lower in SHR-Y compared to WKY-Y (SHR-Y: 70.96% ± 3.65; n = 6, WKY-Y: 85.98% ± 4.18; n = 5-6, p<0.05. Moreover, the 4αPDD-induced response was significantly lower in WKY-A than WKY-Y (WKY-A: 75.58 ± 1.30; n = 5, WKY-Y: 85.98% ± 4.18; n = 5, p<0.05). Immunostaining study showed immunofluorescent signal confined to the endothelial layer of the mesenteric arteries. The expression of TRPV4 mRNA in SHR-Y was significantly lower than in WKY-Y (SHR-Y; 0.67RU ± 0.34; n = 4, WKY-Y: 2.34RU ± 0.15; n = 4, p<0.05). Furthermore, TRPV4 mRNA expression in WKY-A was lower than its expression in WKY-Y (WKY-A: 0.62RU ± 0.37; n = 4, WKY-Y: 2.34RU ± 0.15; n = 4, p<0.05). Conclusion: Stimulation of TRPV4, which is expressed on the endothelium of rat mesenteric artery, triggers an endothelium-mediated relaxation response that markedly decreases with hypertension and growing up changes due to downregulation of TRPV4 expression.

Keywords: hypertension, endothelium, mesenteric artery, TRPV4

Procedia PDF Downloads 307

Authors: Himanshu Kumar Gupta

Abstract:

The Jaisalmer Basin is one of the parts of the Rajasthan basin in northwestern India. The presence of five major unconformities/hiatuses of varying span i.e. at the top of Archean basement, Cambrian, Jurassic, Cretaceous, and Eocene have created the foundation for constructing a sequence stratigraphic framework. Based on basin formative tectonic events and their impact on sedimentation processes three first-order sequences have been identified in Rajasthan Basin. These are Proterozoic-Early Cambrian rift sequence, Permian to Middle-Late Eocene shelf sequence and Pleistocene - Recent sequence related to Himalayan Orogeny. The Permian to Middle Eocene I order sequence is further subdivided into three-second order sequences i.e. Permian to Late Jurassic II order sequence, Early to Late Cretaceous II order sequence and Paleocene to Middle-Late Eocene II order sequence. In this study, Late Jurassic to Early Cretaceous sequence was identified and log-based interpretation of smaller order T-R cycles have been carried out. A log profile from eastern margin to western margin (up to Shahgarh depression) has been taken. The depositional environment penetrated by the wells interpreted from log signatures gave three major facies association. The blocky and coarsening upward (funnel shape), the blocky and fining upward (bell shape) and the erratic (zig-zag) facies representing distributary mouth bar, distributary channel and marine mud facies respectively. Late Jurassic Formation (Baisakhi-Bhadasar) and Early Cretaceous Formation (Pariwar) shows a lesser number of T-R cycles in shallower and higher number of T-R cycles in deeper bathymetry. Shallowest well has 3 T-R cycles in Baisakhi-Bhadasar and 2 T-R cycles in Pariwar, whereas deeper well has 4 T-R cycles in Baisakhi-Bhadasar and 8 T-R cycles in Pariwar Formation. The Maximum Flooding surfaces observed from the stratigraphy analysis indicate major shale break (high shale content). The study area is dominated by the alternation of shale and sand lithologies, which occurs in an approximate ratio of 70:30. A seismo-geological cross section has been prepared to understand the stratigraphic thickness variation and structural disposition of the strata. The formations are quite thick to the west, the thickness of which reduces as we traverse towards the east. The folded and the faulted strata indicated the compressional tectonics followed by the extensional tectonics. Our interpretation is supported with seismic up to second order sequence indicates - Late Jurassic sequence is a Highstand Systems Tract (Baisakhi - Bhadasar formations), and the Early Cretaceous sequence is Regressive to Lowstand System Tract (Pariwar Formation).

Keywords: Jaisalmer Basin, sequence stratigraphy, system tract, T-R cycle

Procedia PDF Downloads 130

Authors: Dongming Feng, Fangyin Zhang, Liling Cao

Abstract:

Horizontally curved steel-concrete composite box girders are extensively used in highway bridges. They consist of reinforced concrete deck on top of prefabricated steel box section beam which exhibits a high torsional rigidity to resist torsional effects induced by the curved structural geometry. This type of structural system is often constructed in two stages. The composite section will take the tension mainly by the steel box and, the compression by the concrete deck. The steel girders are delivered in large pre-fabricated U-shaped sections that are designed for ease of construction. They are then erected on site and overlaid by cast-in-place reinforced concrete deck. The functionality of the composite section is not achieved until the closed section is formed by fully cured concrete. Since this kind of composite section is built in two stages, the erection of the open steel box presents some challenges to contractors. When the reinforced concrete slab is cast-in-place, special care should be taken on bracings that can prevent the open U-shaped steel box from global and local buckling. In the case of multiple steel boxes, the design detailing should pay enough attention to the installation requirement of the bracings connecting adjacent steel boxes to prevent the global buckling. The slope in transverse direction and grade in longitudinal direction will result in some local deformation of the steel boxes that affect the connection of the bracings. During the design phase, it is common for engineers to model the curved composite box girder using one-dimensional beam elements. This is adequate to analyze the global behavior, however, it is unable to capture the local deformation which affects the installation of the field bracing connection. The presence of the local deformation may become a critical component to control the construction tolerance, and overlooking this deformation will produce inadequate structural details that eventually cause misalignment in field and erection failure. This paper will briefly describe the construction issues we encountered in real structures, investigate the difference between beam element modeling and shell/solid element modeling, and their impact on the different construction stages. P-delta effect due to the slope and curvature of the composite box girder is analyzed, and the secondary deformation is compared to the first-order response and evaluated for its impact on installation of lateral bracings. The paper will discuss the rational approach to prepare construction documents and recommendations are made on the communications between engineers, erectors, and fabricators to smooth out construction process.

Keywords: buckling, curved composite box girder, stage construction, structural detailing

Procedia PDF Downloads 117