bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolic load in dairy cows kept in herbage‐based feeding systems and suitability of potential markers for compromised well‐being
Authors: Zbinden R. S. , Falk M. , Münger A. , Dohme‐Meier F. , van Dorland H. A. , Bruckmaier R. M. , Gross J. J.
Published: March 2016

Herbage feeding with only little input of concentrates plays an important role in milk production in grassland dominated countries like Switzerland. The objective was to investigate the effects of a solely herbage‐based diet and level of milk production on performance, and variables related to the metabolic, endocrine and inflammatory status to estimate the stress imposed on dairy cows. Twenty‐five multiparous Holstein cows were divided into a control (C+, n = 13) and a treatment group (C−, n = 12), according to their previous lactation yield (4679–10 808 kg) from week 3 ante partum until week 8 post‐partum (p.p.). While C+ received fresh herbage plus additional concentrate, no concentrate was fed to C− throughout the experiment. Within C+ and C−, the median of the preceding lactation yields (7752 kg) was used to split cows into a high (HYC+, HYC−)‐ and low‐yielding (LYC+, LYC−) groups. Throughout the study, HYC+ had a higher milk yield (35.9 kg/d) compared to the other subgroups (27.2–31.7 kg/d, p < 0.05). Plasma glucose (3.51 vs. 3.72 mmol/l) and IGF‐1 (66.0 vs. 78.9ng/mL) concentrations were lower in HYC−/LYC− compared to HYC+/LYC+ cows (p < 0.05). Plasma FFA and BHBA concentrations were dramatically elevated in HYC− (1.1 and 1.6 mmol/l) compared to all other subgroups (mean values: 0.5 and 0.6 mmol/l, p < 0.05). Saliva cortisol, plasma concentrations of serum amyloid A (SAA), haptoglobin (Hp), beta‐endorphin (BE) and activity of alkaline phosphatase (AP) were not different between C+ and C−. In conclusion, herbage‐fed high‐yielding cows without supplementary concentrate experienced a high metabolic load resulting in a reduced performance compared to cows of similar potential fed accordingly. Low‐yielding cows performed well without concentrate supplementation. Interestingly, the selected markers for inflammation and stress such as cortisol, Hp, SAA, BE and AP gave no indication for the metabolic load being translated into compromised well‐being.
Inhibition of gingipains and Porphyromonas gingivalis growth and biofilm formation by prenyl flavonoids
Authors: Kariu T. , Nakao R. , Ikeda T. , Nakashima K. , Potempa J. , Imamura T.
Published: March 2016

Background and Objective

Porphyromonas gingivalis is considered a major pathogen of chronic periodontitis, which also may be implicated with systemic diseases such as atherosclerosis. Secreted cysteine proteases, gingipains Rgp and Kgp, are essential for P. gingivalis virulence. Some polyphenols and flavonoids are known to inhibit gingipain activity and interfere with biofilm formation by P. gingivalis. Many bioactive compounds have been isolated from Epimedium species, but availability of these compounds on gingipains and P. gingivalis is still unclear. Therefore, the aim of this study was to evaluate natural products from medical plants to develop a new therapeutic agent against periodontal disease.

Material and Methods

Prenylated flavonoids were isolated from Epimedium species plant using column chromatographies. The inhibitory effect of the prenylated flavonoids against protease activity of gingipains were examined using purified gingipains and fluorogenic substrates. Anti‐P. gingivalis activity was evaluated to analyze planktonic growth and biofilm formation in brain heart infusion medium in the presence of the prenylated flavonoids.

Results

We isolated 17 prenylated flavonoids (Limonianin, Epimedokoreanin B, etc.) from Epimedium species. We found that some prenylated flavonoids inhibited gingipain activity in a non‐competitive manner with Ki values at μm order. The prenylated flavonoids also hindered growth and biofilm formation of P. gingivalis, in a manner independent of gingipain inhibition by the compounds.

Conclusion

The results indicated an inhibitory effect of the prenylated flavonoids against P. gingivalis and would provide useful information for future development of periodontitis treatment that suppresses gingipains, P. gingivalis growth and biofilm formation.
Creation of an integrated outcome database for pediatric anesthesia
Authors: Cravero Joseph P. , Sriswasdi Patcharee , Lekowski Rebecca , Carpino Elizabeth , Blum Richard , Askins Nissa , Zurakowski David , Sinnott Sean
Published: March 2016

Outcome analysis is essential to health care quality improvement efforts. Pediatric anesthesia faces unique challenges in analyzing outcomes. Anesthesia most often involves a one‐time point of care interaction where work flow precludes detailed feedback to care givers. In addition, pediatric outcome evaluations must take into account patients' age, development, and underlying illnesses when attempting to establish benchmarks. The deployment of electronic medical records, including preoperative, operative, and postoperative data, offers an opportunity for creating datasets large and inclusive enough to overcome these potential confounders. At our institution, perioperative data exist in five distinct environments. In this study, we describe a method to integrate these datasets into a single web‐based relational database that provides researchers and clinicians with regular anesthesia outcome data that can be reviewed on a daily, weekly, or monthly basis. Because of its complexity, the project also entailed the creation of a ‘dashboard,’ allowing tracking of data trends and rapid feedback of measured metrics to promote and sustain improvements. We present the first use of such a database and dashboard for pediatric anesthesia professionals as well as successfully demonstrating its capabilities to perform as described above.
Bending the rules: a novel approach to placement and retrospective experience with the 5 French Arndt endobronchial blocker in children <2 years
Authors: Templeton T. Wesley , Downard Martina G. , Simpson Christopher R. , Zeller Kristen A. , Templeton Leah B. , Bryan Yvon F.
Published: March 2016

Background

One‐lung ventilation (OLV) is frequently employed to improve surgical exposure during video‐assisted thoracoscopic surgery (VATS) and thoracotomy in adults and children. Because of their small size, children under the age of 2 years are not candidates for some of the methods typically used for OLV in adults and older children, such as a double‐lumen endotracheal (DLT) tube or intraluminal use of a bronchial blocker. Due to this, the clinician is left with few options. One of the most robust approaches to OLV in infants and small children has been the extraluminal placement of a 5 French (5F) Arndt endobronchial blocker (AEB).

Aim

The aim of this retrospective study was to examine and describe our experience with placement and management of an extraluminal 5F AEB for thoracic surgery in children <2 years of age.

Methods

We retrospectively examined the anesthetic records for details of AEB placement, arterial blood gas (ABG) data, and intraoperative analgesic prescription in 15 children under the age of 2 years undergoing OLV with a 5F AEB for thoracic surgery at our institution from January 2010 through January 2016.

Results

We were able to successfully achieve lung isolation in 14 of 15 patients using a 5F AEB that was bent 35–45° 1.5 cm proximal to the inflatable cuff. In 13 of 15 patients, we were able to place the AEB into final position with the aid of video‐assisted fiberoptic bronchoscopy. In two patients, fluoroscopy was required to place the 5F AEB into the left mainstem due to poor visualization of the carina and rapid desaturation during bronchoscopy. In one of these patients, even though the blocker appeared to be correctly placed by fluoroscopy, adequate lung isolation was not observed. Intraoperatively, we observed significant degrees of hypercarbia in most patients without oxygen desaturation. Analgesic regimens lacked consistency and varied among patients. Open thoracotomy procedures tended to receive more aggressive narcotic regimens than video‐assisted thoracoscopic surgery (VATS) procedures. Fourteen of 15 patients were extubated in the immediate postoperative period.

Conclusions

Our technique of placing a 35–45° bend in the AEB, extraluminal placement, and observed manipulation with a video‐assisted flexible fiberoptic bronchoscope (FFB) within the trachea can be used to achieve consistent lung isolation in patients <2 undergoing thoracic surgery. When the use of a FFB proves unsuccessful, fluoroscopy can provide an alternative solution to successful placement. Significant respiratory derangements without long‐term sequelae will occur in a majority of these patients during OLV. Several different approaches to intraoperative analgesia did not impede extubation in the early postoperative period.
Anxiety, Sophistication, and Resistance to Persuasion: Evidence from a Quasi‐Experimental Survey on Global Climate Change
Authors: Nai Alessandro , Schemeil Yves , Marie Jean‐Louis
Published: March 2016

Our contribution deals with the emotional and cognitive foundations of resistance to persuasive information. We rely on an original quasi‐experimental protocol that simulates the flow of information and the respondents' reactions to persuasive arguments on global climate change. Respondents in a representative sample (N = 604) were asked if they supported reduction of economic activity to reduce climate warming and were then provided, based on their support or disapproval for this first argument, with counterattitudinal arguments to test their resistance to persuasion. This article highlights that sophistication strengthens resistance to persuasion, whereas anxiety has a double effect: directly, it decreases resistance; indirectly, it interacts with political sophistication and makes sophisticates less likely to resist persuasion when facing arguments inconsistent with their previous beliefs. Nonanxious citizens, in turn, are more likely to resist persuasion when their political sophistication increases. We also provide evidence that the joint effect of anxiety and sophistication is moderated by the ideological identification of respondents.
Understanding What Shapes a Polycentric Governance System
Authors: Berardo Ramiro , Lubell Mark
Published: March 2016

Recent research has shown that communication networks involving governmental and nongovernmental actors self‐organize based on how risk is perceived. According to the “risk hypothesis,” actors embedded in governance systems in which there is widespread risk of defection tend to form bonding structures, whereas those in low‐risk systems form bridging structures. A parallel strand of research proposes to study complex governance systems composed of multiple actors and the decision‐making forums in which they interact. In this article, the authors couple these research threads and show how bonding and bridging structures form when stakeholders participate in three complex governance systems of varying institutional strength. Findings suggest that the prevalence of one type of structure over the other depends on contextual variables such as the stability of the institutions and the occurrence of environmental focusing events that demand quick policy responses.
HLA‐E polymorphism and soluble HLA‐E plasma levels in chronic hepatitis B patients
Authors: Zidi I. , Laaribi A. B. , Bortolotti D. , Belhadj M. , Mehri A. , Yahia H. B. , Babay W. , Chaouch H. , Zidi N. , Letaief A. , Yacoub S. , Boukadida J. , Di Luca D. , Hannachi N. , Rizzo R.
Published: March 2016

Chronic hepatitis B virus (HBV) infection occurs in association to a deregulation of immune system. Human leukocyte antigen E (HLA‐E) is an immune‐tolerant nonclassical HLA class I molecule that could be involved in HBV progression. To measure soluble (s) HLA‐E in patients with chronic HBV hepatitis (CHB). We tested the potential association of HLA‐E*01:01/01:03 A > G gene polymorphism to CHB. Our cohort consisted of 93 Tunisian CHB patients (stratified in CHB with high HBV DNA levels and CHB with low HBV DNA levels) and 245 healthy donors. Plasma sHLA‐E was determined using enzyme‐linked immunosorbent assay (ELISA). Genotyping was performed using polymerase chain reaction sequence‐specific primer. No association between HLA‐E*01:01/01:03 A > G polymorphism and HBV DNA levels in CHB patients was found. G/G genotype is less frequent in CHB patients without significance. sHLA‐E is significantly enhanced in CHB patients compared with healthy controls (P = 0.0017). Stratification according to HBV DNA levels showed that CHB patients with low HBV DNA levels have higher sHLA‐E levels compared with CHB patients with high HBV DNA levels. CHB patients with G/G genotype have enhanced sHLA‐E levels compared with other genotypes (P = 0.037). This significant difference is maintained only for CHB women concerning G/G genotypes (P = 0.042). Finally, we reported enhanced sHLA‐E in CHB patients with advanced stages of fibrosis (P = 0.032). We demonstrate, for the first time, the association of sHLA‐E to CHB. Owing to the positive correlation of HLA‐E*01:01/01:03 A > G polymorphism and the association of sHLA‐E to advanced fibrosis stages, HLA‐E could be a powerful predictor for CHB progression. Further investigations will be required to substantiate HLA‐E role as a putative clinical biomarker of CHB.
Age decreases mitochondrial motility and increases mitochondrial size in vascular smooth muscle
Authors: Chalmers Susan , Saunter Christopher D. , Girkin John M. , McCarron John G.
Published: March 2016

Key points

Age is proposed to be associated with altered structure and function of mitochondria; however, in fully‐differentiated cells, determining the structure of more than a few mitochondria at a time is challenging. In the present study, the structures of the entire mitochondrial complements of cells were resolved from a pixel‐by‐pixel covariance analysis of fluctuations in potentiometric fluorophore intensity during ‘flickers’ of mitochondrial membrane potential.

Mitochondria are larger in vascular myocytes from aged rats compared to those in younger adult rats.

A subpopulation of mitochondria in myocytes from aged, but not younger, animals is highly‐elongated.

Some mitochondria in myocytes from younger, but not aged, animals are highly‐motile.

Mitochondria that are motile are located more peripherally in the cell than non‐motile mitochondria.

Mitochondrial function, motility and architecture are each central to cell function. Age‐associated mitochondrial dysfunction may contribute to vascular disease. However, mitochondrial changes in ageing remain ill‐defined because of the challenges of imaging in native cells. We determined the structure of mitochondria in live native cells, demarcating boundaries of individual organelles by inducing stochastic ‘flickers’ of membrane potential, recorded as fluctuations in potentiometric fluorophore intensity (flicker‐assisted localization microscopy; FaLM). In freshly‐isolated myocytes from rat cerebral resistance arteries, FaLM showed a range of mitochondrial X‐Y areas in both young adult (3 months; 0.05–6.58 μm2) and aged rats (18 months; 0.05–13.4 μm2). In cells from young animals, most mitochondria were small (mode area 0.051 μm2) compared to aged animals (0.710 μm2). Cells from older animals contained a subpopulation of highly‐elongated mitochondria (5.3% were >2 μm long, 4.2% had a length:width ratio >3) that was rare in younger animals (0.15% of mitochondria >2 μm long, 0.4% had length:width ratio >3). The extent of mitochondrial motility also varied. 1/811 mitochondria observed moved slightly (∼0.5 μm) in myocytes from older animals, whereas, in the younger animals, directed and Brownian‐like motility occurred regularly (215 of 1135 mitochondria moved within 10 min, up to distance of 12 μm). Mitochondria positioned closer to the cell periphery showed a greater tendency to move. In conclusion, cerebral vascular myocytes from young rats contained small, motile mitochondria. In aged rats, mitochondria were larger, immobile and could be highly‐elongated. These age‐associated alterations in mitochondrial behaviour may contribute to alterations in cell signalling, energy supply or the onset of proliferation.
Effect of aerobic fitness on capillary blood volume and diffusing membrane capacity responses to exercise
Authors: Tedjasaputra Vincent , Bouwsema Melissa M. , Stickland Michael K.
Published: March 2016

Key points

Endurance trained athletes exhibit enhanced cardiovascular function compared to non‐athletes, although it is considered that exercise training does not enhance lung structure and function.

An increased pulmonary capillary blood volume at rest is associated with a higher .

In the present study, we compared the diffusion capacity, pulmonary capillary blood volume and diffusing membrane capacity responses to exercise in endurance‐trained males compared to non‐trained males.

Exercise diffusion capacity was greater in athletes, secondary to an increased membrane diffusing capacity, and not pulmonary capillary blood volume.

Endurance‐trained athletes appear to have differences within the pulmonary membrane that facilitate the increased O2 demand needed for high‐level exercise.

Endurance‐trained athletes exhibit enhanced cardiovascular function compared to non‐athletes, allthough it is generally accepted that exercise training does not enhance lung structure and function. Recent work has shown that an increased resting pulmonary capillary blood volume (VC) is associated with a higher maximum oxygen consumption (), although there have been no studies to date examining how aerobic fitness affects the VC response to exercise. Based on previous work, we hypothesized that endurance‐trained athletes will have greater VC compared to non‐athletes during cycling exercise. Fifteen endurance‐trained athletes (HI: 64.6 ± 1.8 ml kg−1 min−1) and 14 non‐endurance trained males (LO: 45.0 ± 1.2 ml kg−1 min−1) were matched for age and height. Haemoglobin‐corrected diffusion capacity (DLCO), VC and diffusing membrane capacity (DM) were determined using the Roughton and Forster () multiple fraction of inspired O2 (FIO2)‐DLCO method at baseline and during incremental cycle exercise up to 90% of peak O2 consumption. During exercise, both groups exhibited increases in DLCO, DM and VC with exercise intensity. Athletes had a greater DLCO and greater DM at 80 and 90% of compared to non‐athletes. However, VC was not different between groups during exercise. In contrast to our hypothesis, exercise VC was not greater in endurance‐trained subjects compared to controls; rather, the increased DLCO in athletes at peak exercise was secondary to an enhanced DM. These findings suggest that endurance‐trained athletes appear to have differences within the pulmonary membrane that facilitate the increased O2 demand needed for high‐level exercise.
A Fuzzy Logic Approach in the Definition of Risk Acceptance Boundaries in Occupational Safety and Health
Authors: Rodrigues Matilde A. , Leão Celina P. , Nunes Eusébio , Sousa Sérgio , Arezes Pedro
Published: March 2016

Organizations need to make decisions about risk acceptance, to decide about the need of risk-reducing measures. In this process, the personal judgments of occupational safety and health (OSH) practitioners have great importance. If on one hand, they have the technical knowledge about risk; on the other hand, the decisions can be dependent on their level of risk acceptance. This paper analyzes judgments of OSH practitioners about the level of risk acceptance, using the fuzzy logic approach. A questionnaire to analyze the reported level of risk acceptance was applied. The questionnaire included 79 risk scenarios, each accounting for the frequency of an accident with more lost workdays than a given magnitude. Through the two-step cluster analysis, three groups of OSH practitioners were identified: unacceptable, tolerable, and realistic groups. A further analysis of the realistic group judgments about risk was performed, using the fuzzy logic approach. The fuzzy sets of input and output variables were determined, and the relationship between the variables was mapped through fuzzy rules. After that, the min–max fuzzy inference method was used. The obtained results show that the risk level is acceptable when input variables are at the lowest value and unacceptable when the risk level is high. The obtained results allow us to better understand the modeling of OSH practitioners’ judgments about risk acceptance, noting the uncertainty related to these judgments.
Gasification of Bio-Waste and Biomass Products Through Exposure to High Density and Low Density Supercritical Water
Authors: Desnoo Bob , Huang Xiao , Ma Weiguo , Yoo Yeong
Published: March 2016

Biomass as a sustainable and renewable energy source is starting to gain momentum, especially as more economical energy extraction methods prevail. Supercritical water biomass gasification (SCWBG) is one of the more promising methods to extract energy from biomass in a gaseous form due to its lower temperature and simpler setup. In this work, two biomass samples (considered livestock feed) and two biomass waste samples are gasified in supercritical water (SCW). To compare the gasification of the real biomass samples (beat skin and straw) to previous works on model biomass compounds, two temperature states (hence different water densities) were used during gasification. An increase in temperature and decrease in water density was found to have similar effects on real biomass compared to that of model compounds. As temperature increases and water density decreases, combustible gas yields tend to increase due to changes in reaction pathways and reaction rates. In this work an analytical comparison is also made between the four different types of biomass in terms of which produce the most combustible gases and of which will generate the most energy. As a result of this analysis beet skins produce the most methane and corn silage yields the most hydrogen. It is the two bio-waste products, however, that generated the largest higher heating values (HHV).
Polytropic Change of State Calculations
Authors: Wettstein Hans E.
Published: March 2016

Polytropic change of state calculations are used within many thermodynamic cycle analysis tasks for turbomachinery like gas turbines or compressors. The typical approach is using formulas, which are theoretically valid for ideal gas conditions only. But often gases are used, which do certainly not behave like ideal gases. This is motivation to check how and which polytropic change of state algorithms can be used for real gases or corresponding mixtures.

There is a vast experience on polytropic efficiencies achievable with existing turbomachinery. Manufacturers calibrate their performance analysis with real test results for compensating potential deviations from their analysis approach. But they normally do not disclose their approaches for the thermodynamic calculation and the corrections made based on their test results. But for investigations of new thermodynamic cycles before the stage of development with an available demonstrator a best possible prediction of the performance is desired.

In this paper the assumptions and formulas for calculating polytropic changes of state and polytropic efficiencies are gathered from literature. The most fundamental assumption is based on a constant dissipation rate during the polytropic change of state. It could be tracked back to Zeuner, Stodola and Dzung. A numerically convenient approximation is the “polytropic exponent approach”. It fulfills the first assumption for an ideal gas but it is only an approximation for real gases.

The temperature after a polytropic change of state is defined by its initial condition, the pressure ratio and the polytropic efficiency. Three different calculation algorithms are compared here: The recursive “constant dissipation rate algorithm” suggested by the author, the most used “ideal gas formula” and the “polytropic exponent formula” as the most used approximation for real gases. Numeric results for compression from 1bar to up to 100bar are shown for dry air, Argon, Neon, Nitrogen, Oxygen and CO2. The deviations of the different calculation approaches are considerable.
Power Efficiency Optimization of Vanadium Redox Batteries Based on Experimental Analysis of Electrolyte Flow Through Carbon Felt of Electrodes
Authors: Pozin A. , Averbukh M. , Sukoriansky S.
Published: March 2016

The Vanadium Redox Flow Battery (VRB) represents a significant opportunity for future Energy Storage Systems (ESS), which will be the crucial element in Renewable Power Plants. Main expectations of VRB relate to its prolonged service life, high-energy efficiency, outstanding dynamic response and flexible controllability during charge/discharge processes. The typical cell of VRB consists of two compartments (positive and negative) divided by a proton exchange membrane (PEM). The carbon electrodes in each compartment provide the electrochemical reduction-oxidation reactions in electrolyte. Carbon felt material as a rule is chosen for electrodes development due to its ability to provide intensive electrochemical reaction owing enlarged external surface and thus a sufficient current (power). The electrolyte on the base of sulfuric acid includes two pairs of vanadium ions with valences: (2+, 3+) in the negative compartment and (4+, 5+) in the positive one. The main volume of electrolyte is stored in two separate tanks and is pumped through both cell’s compartments. There are two main reasons for electrolyte pumping. The first one is the restricted solubility of active vanadium species in sulfuric acid that leads to have an enlarged amount of electrolyte volume, which may be located outside of the cells only. The second reason is the need to decrease concentration polarization effects on the electrode surface. Electric current creates the layer of inactive ions on the electrode surface that increases internal electrical resistance, reduces electromotive force and the battery power. Electrolyte circulation eliminates the effect of polarization but causes hydrodynamic losses. They may be diminished by the optimization of electrolyte flow rate based on correct description of hydrodynamic properties of a carbon felt and on accurate depiction of battery electrical losses.

The present research proposes a novel approach to optimization of electrolyte pumping with the purpose to obtain maximum VRB efficiency.
High Temperature Air Combustion (HiTAC) Phenomena and its Thermodynamics
Authors: Rafidi Nabil , Blasiak Wlodzimierz , Gupta Ashwani K.
Published: March 2016

The fundamentals and thermodynamic analysis of High Temperature Air Combustion (HiTAC) technology is presented with focus on industrial furnaces as they are amongst the major energy users. The HiTAC is characterized by high temperature of combustion air having low oxygen concentration. This study provides a theoretical analysis of HiTAC a process from the thermodynamic point of view. The results demonstrate the possibilities of reducing thermodynamic irreversibility of combustion by considering an oxygen-deficient combustion process that utilizes both gas- and heat-recirculation. Furthermore, combustion with the use of oxygen (in place of air) is also analyzed. The results showed that a system which utilizes oxygen as an oxidizer results in higher 1st and 2nd law efficiencies as compared to the case with air as the oxidizer. This study is aimed at providing technical guidance to further improve efficiency of a combustion process which show very small temperature increases due to mild chemical reactions. The significant of these findings are now widely used in industrial furnaces with singular successes on energy savings, pollution reduction and reduced size of the equipment. The exergy analysis too can be used as a technical tool to improve efficiency in combustion processes.
Operational Costs Optimization in Water Distribution Systems
Authors: Al-Ani Dhafar , Afshari HamedHossien , Habibi Saeid
Published: March 2016

Pump management and reservoir management have many similarities, and therefore, should ideally be analyzed in an integrated way to plan effectively the daily operation of water distribution systems. Historically, these two management activities have been evolved as separate tasks in energy-efficiency (i.e., energy optimization) studies and are often carried out in an isolated way. The latter being most often associated directly with the concepts of multimodal and multi-objective optimization problems, whereas the former is usually considered as a single optimization problem to be solved. When some single optimization problems appear at part of the solution tied to a local (i.e., regional) search-space (i.e., objective space), this artificial integration (i.e., multi-modal and multi-objective optimization) can always obtain optimal solutions. Similarly when system constraints and load conditions are considered, a set of feasible and innovative optimal solutions can be obtained in order to continue the enhancement of energy consumption that turns into a significant reduction in the overall operational cost (i.e., a potential of 6.24% cost savings) without affecting the level of services provided to the clients in a safe and protected manner.
An Experimental Study of Performance and Emission on Ethanol Fuelled Pre and Post Injection in High Compression Ignition Engine With Zirconia Coating
Authors: Murugasen Velliangiri , Gurusamy Sureshkannan , Srinivasan Krishnan Annur
Published: March 2016

The research article presented here mainly focuses on the influence of pre and post-injection (split in to three injections) technique that was used to improve the ethanol fuel combustion in compression ignition mode (CI), with and without zirconia surface coating. Combustion simulation results and experimental results were investigated and compared with different experimental conditions. This research was used (95% Ethanol +5% water) as a fuel in a four stroke single cylinder variable compression ratio (VCR) engine. The VCR engine was used to optimize compression ratio (28.8:1) and conducted various experiments. Performance and exhaust emissions of NOx, CO and HC were compared with ethanol fuel split injection mode, single injection mode and diesel fuel mode. Brake thermal efficiency of pre and post injection mode was better than direct injection (DI) ethanol mode. The VCR engine operating with ethanol fuel split injection mode showed peak brake thermal efficiency (BTE) of 29%, which is nearly operating range in the baseline diesel engine. Ethanol fuel was mixed with 3% castorene R40 (lubrication oil) oil by volume due to fully soluble in alcohol fuels. It was used both air and liquid cooled engines running on methanol and ethanol fuel. Pre and post ethanol injection mode was 54.4 % reduction of Oxides of nitrogen (NOx) compared with single injection mode of operation. In comparison of diesel mode operation with zirconia coating was 3.8% increased than without coating.
Cooling of Turbine Blade Surface With Extended Exit Holes: Parametric Study
Authors: Forghan Fariborz , Askari Omid , Narusawa Uichiro , Metghalchi Hameed
Published: March 2016

Turbine blade surface is cooled by jet flow from extended exit holes (EEH). Cooling effectiveness is defined as temperature difference (TD) between the hot gas flow and the blade surface as a fraction of temperature difference between the hot gas flow and the coolant flow through EEH. Computational research using a commercial code has been done to predict performance of EEH for different design and operating conditions. Effectiveness has been determined over the blade surface when geometric conditions such as: angle between EEH and blade surface, location of EEH on the blade surface and exit-to-throat area ratio of EEH. Predicted effectiveness distributions agree well with available experimental results, confirming usefulness and advantage of computational approach to optimizing turbine blade cooling with EEH.
Laminar Partially Premixed Flames of Blends of Pre-Vaporized Jet-A Fuel and Palm Methyl Ester
Authors: Balakrishnan Arun , Parthasarathy Ramkumar N. , Gollahalli Subramanyam R.
Published: March 2016

Biofuels, such as palm methyl ester (PME), are attractive alternates to petroleum fuels. In order to isolate the effects of fuel chemistry on the combustion properties, laminar partially premixed pre-vaporized flames of blends of Jet-A and PME (volume concentrations of 25%, 50%, 75% PME) were studied. A stainless steel circular tube (ID of 9.5 mm) served as the burner. The liquid fuel was supplied with a syringe pump into a high temperature (390°C) air flow to vaporize it completely without coking. The fuel flow rate was maintained constant and the air flow rate adjusted to obtain burner-exit equivalence ratios of 2, 3 and 7. The global flame properties including flame length, CO and NO emission indices, radiative heat fraction and in-flame properties including gas concentration (CO, CO2, NO, O2), temperature and soot volume fraction were measured. The near-burner homogeneous gas-phase reaction zone increased in length with the addition of PME at all equivalence ratios. The concentration and global emission measurements highlight the non-monotonic variation of properties with the volume concentration of PME in the fuel. The fuel-bound oxygen of PME affected the combustion properties significantly.
Solar Thermal Power Generation Using a Double Concentration on a Dish Collector
Authors: Imam Ramy Khalid Zakaria El Adli , Yassin Mohamed , Donia Mohamed , Atiya Ahmed
Published: March 2016

In order to deal with the shortage in energy using clean renewable energy, a highly efficient and economical solution is needed to meet consumer energy needs. To achieve that, a solar dish collector was established with some major modification in the collection of solar energy to decrease manufacturing cost and increase efficiency. In addition, the focal point of the system was modified using an optical system to establish greater light concentration. This was done using a series of tests, on the different optical assemblies, which affected the performance, efficiency, durability, and cost of the system. Finally, an optical assembly that was used has shown that it can reduce the shadow on the primary mirror, decrease the manufacturing cost of the structure, and increase the efficiency of the system.
Highlights of Fuel Cell Modeling From a Lattice Boltzmann Method Point of View
Authors: Espinoza Mayken , Sundén Bengt , Andersson Martin
Published: March 2016

Relative simplicity of use, no pollutions and high-efficiency are some of the advantages that will make fuel cells one of the best devices for getting electrical energy in the near future. Micro- and mesoscale modeling of fuel cells gives an important perspective about their efficiency and behavior during the energy conversion process. Due to the high cost of carrying out laboratory experiments related to different materials at the micro- and mesoscales, modeling and simulation of the different elements of the fuel cells are a useful approach and a point of departure for the experimental validation.

This paper describes fuel cell modeling starting with the fundamentals, including physical and chemical characteristics of fuel cells, moving to the current state of the study of modeling based on the Lattice Boltzmann Method (LBM). The principal characteristics and elements of the fuel cells are presented in general as well as the main differences between the Proton Exchange Membrane Fuel Cells (PEMFC) and Solid Oxide Fuel Cells (SOFC). Fuel cells have several parts that are modeled on the micro- and mesoscale level. These parts, conditions and governing equations for different transport phenomena are displayed in this manuscript. A detailed description of the main issues, advantages and recent advances related to Lattice Boltzmann Method as a method for modeling several physical processes that take place within fuel cells are presented.
Modeling of a Hybrid Energy System Integrated With an Intermittent Power Grid in Developing Countries
Authors: Oke Kehinde , Bello Olumide , Onyebueke Landon
Published: March 2016

Electricity in most developing countries is inefficient, erratic and unreliable. Recent research work on grid-connected hybrid system in developing countries have not considered frequent electricity outage hours per month experienced by consumers. Effort is made to address this critical factor and HOMER software was used to model an intermittent power grid integrated with a hybrid energy system. This shortcoming is addressed by assuming generator component in HOMER to run as grid. This is made possible after some modification to fuel content, minimum load capacity ratio and scheduling capacity of the generator. A city in Nigeria was used to demonstrate this approach, but it can be replicated for any location in developing countries where there is frequent electricity outage. Outcome of the model shows that integrating an intermittent power grid with a hybrid energy system offers a competitive cost of energy, reduction in noise pollution and improved use of renewable energy for electricity generation in developing countries.
The Thermal State Numerical Simulation and the Security Analysis to the Superheaters of the Ultra-Supercritical Boiler in FCB
Authors: Zhi-gang Zhan , Kun Qian , Yang-heng Xiong , Ya-wei Chen , Zhan Xiong
Published: March 2016

A successful FCB (Fast Cut Back) can increase the security of the power plant and electric grid. On the other hand, in ultra-supercritical boilers, the superheaters suffer higher temperature, higher stress and severer oxidation on steam side. In this article, a numerical simulation on the temperature and stress of the superheaters, considering the double oxide scale on steam side, respectively in the process of 100%, 50% FCB (Fast Cut Back) and 100%, 75%, 50% load shedding, is conducted. The change law of the operation state is discussed. The results show that the higher the load before the operation condition change is, the greater range temperature and stress of the scale changes in, and the stress of the scale is affected by the steam temperature and steam pressure at the same time. The highest equivalent strain appears on the interface of the double scale, and its value is close to the spalling value. The oxide scale on the steam side of superheaters has high potential risk of spalling, great attention should be paid to them.
Water Management in Fuel Cell Stack by Using Microcontroller
Authors: Rajaram Gukan , Panthalingal Manoj Kumar , Valivittan Parthasarathy
Published: March 2016

Proton Exchange Membrane Fuel Cell (PEMFC) is very good at producing energy without the emission of any harmful gases. In this work, emphasis has been given towards controlling the water accumulation inside the cell stack. The effective cooling of the fuel cell during operation can significantly improve the efficiency. Also, flooding and dehydration conditions are most common reasons for the efficiency reduction and performance degradation of the fuel cells. In the current work, the problem is addressed by controlling the number of cells in operation through a specifically designed microcontroller. The controller would switch the cells on/off when the need arises which can be diagnosed by thermocouple by virtue of cell temperature. Automatic switching with the microcontroller is performed without disturbing the stack operation. This could improve the cell performance with reduced flooding/dehydration of the stack. So the same stack life may be improved substantially.
Potential Reduction of Fugitive Methane Emissions at Compressor Stations and Storage Facilities Powered by Natural Gas Engines
Authors: Johnson Derek , Covington April
Published: March 2016

The American Gas Association (AGA) and the United States (US) Energy Information Administration (EIA) report that natural gas reserves, production, and consumption are increasing. Current estimates show over 100 years worth of recoverable reserves. As production increases, the natural gas pipeline interstate will grow or at least experience increased throughput. With the industry expanding at rapid rates and the high global warming potential of methane (21 over a 100 year period), it is important to identify potential sources for reductions in fugitive methane emissions. This research group conducted leak and loss audits at five natural gas compressor station and storage facilities. The majority of methane losses were associated with the operation of the lean-burn, natural gas engines (open crankcases, exhaust), compressor seal vents, and open liquid storage tanks. This paper focuses on the potential reduction in fugitive methane emissions of the discovered industry weaknesses through application of various proven technologies. As engines are not perfectly sealed, blow-by of intake air, fuel, and combustion gases occurs past the piston rings. In order to prevent a build-up of pressure within the crankcase, it must be vented. Diesel engines have lower hydrocarbon emissions from their crankcases due to the short duration of fuel addition after compression of the intake charge. Lean-burn, natural gas engines, like conventional gasoline engines, compress both the fuel and intake air during the compression stroke. During the 1960s, many passenger vehicles adopted positive crankcase ventilation (PCV) or closed crankcase ventilation (CCV) systems to reduce significantly hydrocarbon emissions from engines. Currently, some heavy-duty on-road engines still have open crankcase systems and most off-road engines have crankcases simply vented to the atmosphere. In this paper, researchers will examine the potential reduction in methane emissions that could be realized with the installation of retrofitted CCV systems at these locations. In addition to the reduction of methane losses from the crankcase, it is realized that with proper plumbing, flow control, and safety parameters, all of the losses typically vented to atmosphere could be ducted into the engine intake for combustion. Preliminary results show that applications of closed crankcase systems could reduce emissions from these sites by 1–11% while modifying these systems to include the losses from compressor seal vents and storage tanks could yield potential reductions in methane emissions by 10–57%.
Characteristics of Water-in-Diesel Emulsions in a Single Cylinder Compression Ignition Engine
Authors: Gonguntla Teja , Raine Robert , Ramsey Leigh , Houlihan Thomas
Published: March 2016

The objective of this project was to develop both engine performance and emission profiles for two test fuels — a 6% water-in-diesel oil emulsion (DOE-6) fuel and a neat diesel (D100) fuel. The testing was performed on a single cylinder, direct-injection, water-cooled diesel engine coupled to an eddy current dynamometer. Output parameters of the engine were used to calculate Brake Specific Fuel Consumption (BSFC) and Engine Efficiency (η) for each test fuel. DOE-6 fuels generated a 24% reduction in NOX and a 42% reduction in Carbon Monoxide emissions over the tested operating conditions. DOE-6 fuels presented higher ignition delays — between 1°-4°, yielded 1%–12% lower peak cylinder pressures and produced up to 5.5% lower exhaust temperatures. Brake Specific Fuel consumption increased by 6.6% for the DOE-6 fuels as compared to the D100 fuels. This project is the first research done by a New Zealand academic institution on water-in-diesel emulsion fuels.
Finite Time Thermodynamics Model of an Absorption Chiller
Authors: Gerlach David , Liao Xiaohong
Published: March 2016

A finite time thermodynamic model of an absorption chiller was developed. The effects of irreversibilities due to finite rate heat transfer in the heat exchangers are modeled by using the standard UA formulation with the absorber and condenser lumped as one heat exchanger. In order to match experimental data within 20%, the UA of the generator was modeled as a linear function of the heating fluid flow rate. A constant entropy production due to internal processes was included to model reduction in performance at off design conditions. The UA parameters and internal entropy production constant form a set of five fitting parameters with physical meaning. This is fewer parameters than the non-physical curve fit used in the industry standard Energy Plus model. The model was validated within 20% against data sets from two different systems.
An Investigation of Microclimatic Impact of Cool Coating for Buildings in Low-Latitude and Tropical Climate
Authors: Zingre Kishor T. , Yang Xingguo , Wan Man Pun
Published: March 2016

This study investigates the impact of cool coating on air-conditioning energy savings and micro-climate of buildings in low-latitude and tropical climate by performing a computational study. The computational study was carried out using Integrated Environmental Solutions (IES) software which is plugged in with Computational Fluid Dynamics (CFD) program [1]. IES simulations (which uses the heat balance equations at building envelope surfaces and in indoor environment) were performed to investigate the roof surface temperature, while CFD simulations (which uses the Finite Volume Method) were performed to investigate the impact on micro-climate above a real-size single storey air-conditioned building. The computational models in the software were validated by comparing the simulations results against the experimental results obtained from the test building in the industrial area of Nanyang Technological University (NTU), Singapore. Results showed that by applying a cool coating having solar reflectivity of 0.8 on the concrete roof with original solar reflectivity of 0.27, the surface temperatures of roof and ceiling can be reduced by up to 17.5°C and 1.2°C respectively in an air-conditioned room maintain at 22°C. In addition, after applying this high solar reflectance coating, a maximum reduction of 1.0°C, 0.7°C and 0.6°C for air temperature at a height of 0.5 m, 1 m and 1.5 m above the roof surface could be achieved.
Thermodynamic Analysis and Working Fluid Optimization of a Combined ORC-VCC System Using Waste Heat From a Marine Diesel Engine
Authors: Bounefour Oumayma , Ouadha Ahmed
Published: March 2016

This paper examines through a thermodynamic analysis the feasibility of using waste heat from marine Diesel engines to drive a vapor compression refrigeration system. Several working fluids including propane, butane, isobutane and propylene are considered. Results showed that isobutane and Butane yield the highest performance, whereas propane and propylene yield negligible improvement compared to R134a for operating conditions considered.
Improvement of the thermal stability of nickel silicide using a ruthenium interlayer deposited via remote plasma atomic layer deposition
Authors: Lee Inhye , Park Jingyu , Jeon Heeyoung , Kim Hyunjung , Shin Changhee , Shin Seokyoon , Lee Kunyoung , Jeon Hyeongtag
Published: March 2016

In this study, the effects of a thin Ru interlayer on the thermal and morphological stability of NiSi have been investigated. Ru and Ni thin films were deposited sequentially to form a Ni/Ru/Si bilayered structure, without breaking the vacuum, by remote plasma atomic layer deposition (RPALD) on a p-type Si wafer. After annealing at various temperatures, the thermal stabilities of the Ni/Ru/Si and Ni/Si structures were investigated by various analysis techniques. The results showed that the sheet resistance of the Ni/Ru/Si sample was consistently lower compared to the Ni/Si sample over the entire temperature range. Although both samples exhibited the formation of NiSi2 phases at an annealing temperature of 800 °C, as seen with glancing angle x-ray diffraction, the peaks of the Ni/Ru/Si sample were observed to have much weaker intensities than those obtained for the Ni/Si sample. Moreover, the NiSi film with a Ru interlayer exhibited a better interface and improved surface morphologies compared to the NiSi film without a Ru interlayer. These results show that the phase transformation of NiSi to NiSi2 was retarded and that the smooth NiSi/Si interface was retained due to the activation energy increment for NiSi2 nucleation that is caused by adding a Ru interlayer. Hence, it can be said that the Ru interlayer deposited by RPALD can be used to control the phase transformation and physical properties of nickel silicide phases.