bluuebunny/crossref_metadata_2025 huggingface dataset:
Survival of embryos and calves derived from somatic cell nuclear transfer in cattle: a nationwide survey in Japan
Authors: WATANABE Shinya , NAGAI Takashi
Published: March 2011

To obtain data concerning the survival of embryos and calves derived from somatic cell nuclear transfer (SCNT) in Japan, a nationwide survey was carried out in April, 2009. As a result, data concerning 3264 embryo transfers (ETs) with SCNT embryos which produced 301 calves were accumulated and their survival was analyzed. The present survey revealed that survival rates of transferred bovine embryos and produced calves derived from SCNT had not improved over a decade (1998–2007). A remarkable feature of the pregnancies with SCNT embryos was a high incidence of spontaneous abortions. When the decade was divided by the occurrence of bovine spongiform encephalopathy (BSE) in 2001, significant decreases in the ‘after BSE’ period (2002–2007) were observed in the percentages of calves born (P < 0.01), calves living at birth (P < 0.05), calves living for 24 h (P < 0.05) and 6 months (P < 0.01). Abortions that occurred during 61–99 days after ETs were significantly increased (P < 0.01) in the ‘after BSE’ period. Certain kinds of regeneration that occurred in oocytes during the 15–20 h of storage of bovine ovaries at 10–15°C as a part of BSE inspection might have had some negative effects on SCNT embryos when these oocytes were used as recipients of SCNT.
Economic effects of using sexed semen in Japanese dairy herds
Authors: SASAKI Osamu , KIMURA Hirohisa , ISHII Kazuo , SATOH Masahiro , NAGAMINE Yoshitaka , YOKOUCHI Kunio
Published: March 2011

Dairy farm agricultural income should increase when sexed semen is used instead of unsexed semen. This study simulated three scenarios: using unsexed semen (N), using X sperm of Holstein and unsexed semen of Japanese Black (H), and using X sperm of Holstein and Y sperm of Japanese Black (HJ). Two management scenarios were considered: conventional management (CONV); and the use of Japanese Black semen with surplus cows to produce F1s where sufficient replacement female Holstein calves were obtained for maintenance (MAINT). In CONV, the agricultural incomes of H and HJ were 610 000–2 400 000 yen higher than that of N. The agricultural income increased when the difference in the prices between Holstein males and average F1 male/female calves was 34 000–50 000 yen, that between Holstein male and female calves was 80 000–110 000 yen, and that between F1 male and female calves was 50 000–90 000 yen. Therefore, the agricultural income can be increased by using sexed semen to select calves of a more valued breed and sex.
A structured RNA in hepatitis B virus post‐transcriptional regulatory element represses alternative splicing in a sequence‐independent and position‐dependent manner
Authors: Huang Chen , Xie Mao‐Hua , Liu Wei , Yang Bo , Yang Fan , Huang Jingang , Huang Jie , Wu Qijia , Fu Xiang‐Dong , Zhang Yi
Published: March 2011

Hepatitis B virus (HBV) transcripts are subjected to multiple splicing decisions, but the mechanism of splicing regulation remains poorly understood. In this study, we used a well‐investigated alternative splicing reporter to dissect splicing regulatory elements residing in the post‐transcriptional regulatory element (PRE) of HBV. A strong intronic splicing silencer (ISS) with a minimal functional element of 105 nucleotides (referred to as PRE‐ISS) was identified and, interestingly, both the sense and antisense strands of the element were found to strongly suppress alternative splicing in multiple human cell lines. PRE‐ISS folds into a double‐hairpin structure, in which substitution mutations disrupting the double‐hairpin structure abolish the splicing silencer activity. Although it harbors two previously identified binding sites for polypyrimidine tract binding protein, PRE‐ISS represses splicing independent of this protein. The silencing function of PRE‐ISS exhibited a strong position dependence, decreasing with the distance from affected splice sites. PRE‐ISS does not belong to the intronic region of any HBV splicing variants identified thus far, preventing the testing of this intronic silencer function in the regulation of HBV splicing. These findings, together with the identification of multiple sense–antisense ISSs in the HBV genome, support the hypothesis that a sequence‐independent and structure‐dependent regulatory mechanism may have evolved to repress cryptic splice sites in HBV transcripts, thereby preventing their aberrant splicing during viral replication in the host.
Targeted disruption of one of the importin α family members leads to female functional incompetence in delivery
Authors: Moriyama Tetsuji , Nagai Masahiro , Oka Masahiro , Ikawa Masahito , Okabe Masaru , Yoneda Yoshihiro
Published: March 2011

Importin α mediates the nuclear import of proteins through nuclear pore complexes in eukaryotic cells, and is common to all eukaryotes. Previous reports identified at least six importin α family genes in mice. Although these isoforms show differential binding to various import cargoes in vitro, the in vivo physiological roles of these mammalian importin α isoforms remain unknown. Here, we generated and examined importin α5 knockout (impα5−/−) mice. These mice developed normally, and showed no gross histological abnormalities in most major organs. However, the ovary and uterus of impα5−/− female mice exhibited hypoplasia. Furthermore, we found that impα5−/− female mice had a 50% decrease in serum progesterone levels and a 57% decrease in progesterone receptor mRNA levels in the ovary. Additionally, impα5−/− uteruses that were treated with exogenous gonadotropins displayed hypertrophy, similarly to progesterone receptor‐deficient mice. Although these mutant female mice could become pregnant, the total number of pups was significantly decreased, and some of the pups were dead at birth. These results suggest that importin α5 has essential roles in the mammalian female reproductive organs.
Menopausal Status in Breast Cancer Patients with Past Chemotherapy Determines Long-Term Hypoactive Sexual Desire Disorder
Authors: Ochsenkühn Robert , Hermelink Kerstin , Clayton Anita H. , von Schönfeldt Viktoria , Gallwas Julia , Ditsch Nina , Rogenhofer Nina , Kahlert Steffen
Published: March 2011

Introduction

Chemotherapy and endocrine treatment in young breast cancer patients are frequently associated with abrupt menopause. Little is known about the long-term prevalence of hypoactive sexual desire disorder (HSDD) in these patients.

Aims

To examine the effects of adjuvant endocrine therapy on sexual desire in premenopausal patients with breast cancer and past chemotherapy.

Methods

A controlled, cross-sectional study enrolled 47 women with breast cancer or benign breast disease at a tertiary care center. A standardized questionnaire (Sexual Interest and Desire Inventory-Female; SIDI-F) on HSDD was utilized. Serum concentrations for estradiol were measured by a specific assay.

Main Outcome Measures

The SIDI-F interview was applied in 35 women with breast cancer (mean age: 42.3 years) with eventual adjuvant endocrine therapy, 2–8 years after chemotherapy, and 13 women with benign breast tumors (mean age: 39.8 years), 2–5 years after diagnosis.

Results

Mean SIDI-F scores were similar in the breast cancer group (32.9) and the benign breast disease group (34.0). Subgroup analysis revealed no statistical differences in the mean SIDI-F scores with respect to the actual endocrine therapy. However, in breast cancer patients with menopause induced by chemotherapy or gonadotropin-releasing hormone (GnRH) agonists, the SIDI-F scores were significantly lower (30.7) compared to breast cancer patients with menorrhea (40.4). In breast cancer patients, amenorrhea was associated with significantly lower estradiol levels compared to menorrhea (24 pg/mL vs. 91 pg/mL; P  = 0.02).

Conclusions

Cancer treatment that leads to long-term ovarian failure in breast cancer patients has a negative impact on sexual desire. Patients with menopause induced by chemotherapy or GnRH agonists show significantly reduced sexual desire as compared to menstruating patients with past chemotherapy.
Increased reproductive capacity and physical defense but decreased tannin content in an invasive plant
Authors: Guo Wen‐Feng , Zhang Jun , Li Xiao‐Qiong , Ding Jian‐Qing
Published: March 2011

Abstract  Plant invasions create novel plant–insect interactions. The EICA (evolution of increased competitive ability) hypothesis proposes that invasive plants will reallocate resources from defense to growth and/or reproduction because they have escaped from their co‐evolved insect natural enemies. Testing multiple herbivory by monophagous and oligophagous herbivores and simultaneous measurement of various plant traits will provide new insights into the evolutionary change of invasive plants. In this context, we conducted a common garden experiment to compare plant growth and reproduction, chemical and physical defense, and plant responses to herbivory by different types of herbivores between invasive North American populations and native East Asian populations of mile‐a‐minute weed, Persicaria perfoliata. We found that invasive mile‐a‐minute exhibited lower biomass, flowered earlier and had greater reproductive output than plants from the native range. Compared with native populations, plants from invasive populations had lower tannin content, but exhibited higher prickle density on nodes and leaves. Thus our results partially support the EICA hypothesis. When exposed to the monophagous insect, Rhinoncomimus latipes and the oligophagous insects, Gallerucida grisescens and Smaragdina nigrifrons, more damage by herbivory was found on invasive plants than on natives. R. latipes, G. grisescens and S. nigrifrons had strong, moderate and weak impacts on the growth and reproduction of mile‐a‐minute, respectively. The results indicate that mile‐a‐minute may have evolved a higher reproductive capacity in the introduced range, and this along with a lack of oligophagous and monophagous herbivores in the new range may have contributed to its invasiveness in North America.
Groundwater Sampling at ISCO Sites: Binary Mixtures of Volatile Organic Compounds and Persulfate
Authors: Huling Scott G. , Ko Saebom , Pivetz Bruce
Published: March 2011

In situ chemical oxidation involves the introduction of a chemical oxidant into the subsurface for the purpose of transforming groundwater contaminants into harmless by‐products. Owing to oxidant persistence, groundwater samples collected at hazardous waste sites may contain both the contaminant(s) and the oxidant in a “binary mixture.” Binary mixtures composed of sodium persulfate (2.5 g/L; 10.5 mM) and volatile organic compounds (VOCs) (benzene, toluene, m‐xylene, perchloroethylene, trichloroethylene) were analyzed to assess the impact on the quality of the sample. A significant decline (49 to 100%) in VOC concentrations was measured in binary mixtures using gas chromatography (GC) purge and trap, and GC mass spectroscopy headspace methods. Preservation of the binary mixture samples was achieved through the addition of ascorbic acid (99 to 100% VOC average recovery). High concentrations of ascorbic acid (42 to 420 mM) did not interfere in the measurement of the VOCs and did not negatively impact the analytical instruments. High concentrations of ascorbic acid favored the reaction between persulfate and ascorbic acid while limiting the reaction between persulfate and VOCs. If an oxidant is detected and the binary sample is not appropriately preserved, the quality of the sample is likely to be compromised.
Biologic Activity of a Dinuclear Pd(II)–Spermine Complex Toward Human Breast Cancer
Authors: Fiuza Sónia M. , Holy Jon , Batista de Carvalho Luis A. E. , Marques Maria P. M.
Published: March 2011

A dinuclear palladium‐based complex (Pd2‐Spm) was synthesized and compared with cisplatin (cDDP) on two different human breast cancer cell lines (MCF‐7 and MDA‐MB‐231) as well as toward an untransformed cell line (BJ fibroblasts). The results obtained show that Pd2‐Spm is more effective against the estrogen receptors [ER(−)] cell line MDA‐MB‐231, while cDDP displayed better results for the ER(+) MCF‐7 cell line. It was shown that, like cDDP, Pd2‐Spm triggers phosphorylation of H2AX, indicating that this compound damages DNA. Apart from DNA, Pd2‐Spm also targets the cytoskeleton having a greater impact on cell morphology than cDDP. Pd2‐Spm and cDDP have opposite antiproliferative activities in the presence of the PI3K inhibitor wortmannin. Furthermore, Pd2‐Spm at an optimized concentration displays a rapid antiproliferative effect as opposed to cDDP, which seems to have a slower kinetics. The results point to a distinct mechanism of action for each of these complexes, which may explain their synergistic action when coadministrated.
An Innovative Piezoelectric‐Based Method for Measuring Pulse Wave Velocity in Patients With Hypertension
Authors: Murphy John C. , Morrison Katherine , McLaughlin James , Manoharan Ganesh , Adgey AA Jennifer
Published: March 2011

J Clin Hypertens (Greenwich). 2011;13:497–505.©2011 Wiley Periodicals, Inc.

Pulse wave velocity (PWV) is an accepted surrogate marker of arterial stiffness and may be a useful tool for assessing cardiovascular risk in hypertensive patients. The authors sought to compare a novel polyvinylidene fluoride (PVDF) piezoelectric–based sensing device for measuring PWV in the arm with a validated SphygmoCor device (AtCor Medical, West Ryde, Australia) in normal and hypertensive patients. They also sought to compare measured PWV in the forearm (brachial‐radial PWV [BRPWV]) with values obtained in the carotid‐radial segment (carotid‐radial PWV [CRPWV]). Under standardized conditions, CRPWV in 108 normotensive patients with both devices was measured. BRPWV was measured with the PVDF device. Identical measurements were made in a group of 82 hypertensive patients before and after optimization of blood pressure control. Mean CRPWV was 8.7 m/s in the normotensive group and 9.4 m/s in the hypertensive group. Mean BRPWV was 9.2 m/s in the normotensive group and 10.3 m/s in the hypertensive group. There was excellent correlation between the 2 devices when comparing individual CRPWV values (normotensive group,R2=0.92; mean bias 0.04 m/s; hypertensive group,R2=0.89, mean bias 0.08 m/s). Correlation was also favorable when measuring changes in CRPWV in hypertensive patients undergoing pharmacotherapy (PVDF −0.52±0.90 m/s vs SphygmoCor −0.53±1.01 m/s;R2=0.81). Measured values for BRPWV were significantly higher than CRPWV values, and this discrepancy was more marked in the hypertensive group. The PVDF piezoelectric device has excellent correlation with the validated SphygmoCor device when measuring PWV. This novel device may have an important role in patients with conditions such as hypertension.
Gas market developments and their effect on relations between Russia and the EU
Authors: Boussena Sadek , Locatelli Catherine
Published: March 2011

The changes on the European Union (EU) gas market are likely to affect Europe's relations with its natural gas suppliers who are facing increasing competition. Heading this list of producing countries is Russia. Gas relations between Russia and the EU are characterised by strong interdependence. But these relations are currently being hampered by serious lack of understanding, making it difficult for the two parties to reach agreement on a new energy partnership. The aim of this article is to analyse the effects of this new European gas context on Gazprom's strategy and how the issues of energy security and cooperation between Russia and the EU will be affected by this new order.
Discovery of single‐nucleotide polymorphisms (SNPs) in the uncharacterized genome of the ascomycete Ophiognomonia clavigignenti‐juglandacearum from 454 sequence data
Authors: BRODERS K. D. , WOESTE K. E. , SanMIGUEL P. J. , WESTERMAN R. P. , BOLAND G. J.
Published: March 2011

The benefits from recent improvement in sequencing technologies, such as the Roche GS FLX (454) pyrosequencing, may be even more valuable in non‐model organisms, such as many plant pathogenic fungi of economic importance. One application of this new sequencing technology is the rapid generation of genomic information to identify putative single‐nucleotide polymorphisms (SNPs) to be used for population genetic, evolutionary, and phylogeographic studies on non‐model organisms. The focus of this research was to sequence, assemble, discover and validate SNPs in a fungal genome using 454 pyrosequencing when no reference sequence is available. Genomic DNA from eight isolates of Ophiognomonia clavigignenti‐juglandacearum was pooled in one region of a four‐region sequencing run on a Roche 454 GS FLX. This yielded 71 million total bases comprising 217 000 reads, 80% of which collapsed into 16 125 754 bases in 30 339 contigs upon assembly. By aligning reads from multiple isolates, we detected 298 SNPs using Roche’s GS Mapper. With no reference sequence available, however, it was difficult to distinguish true polymorphisms from sequencing error. Eagleview software was used to manually examine each contig that contained one or more putative SNPs, enabling us to discard all but 45 of the original 298 putative SNPs. Of those 45 SNPs, 13 were validated using standard Sanger sequencing. This research provides a valuable genetic resource for research into the genus Ophiognomonia, demonstrates a framework for the rapid and cost‐effective discovery of SNP markers in non‐model organisms and should prove especially useful in the case of asexual or clonal fungi with limited genetic variability.
Nordisk ophthalmologisk tidsskrift 1889–1892
Authors: Ehlers Niels
Published: March 2011

In the second half of the nineteenth century several ophthalmological journals appeared (Germany, England, France, United States). In the northern countries (Denmark, Finland, Norway, Sweden) an initiative lead to ‘Nordisk ophthalmologisk Tidsskrift’ published in the scandinavian languages in the years 1889–92. The ‘driving force’ behind the journal was the first professor in Ophthalmology in Copenhagen, Dr. Edmund Hansen Grut. The purpose with this presentation is to give the background for the rise and fall of the journal which was an attempt to promote Nordic Ophthalmology. The authors turned out, however, to be mainly those involved as editors. The journal never gained broad acceptance and it simply stopped in 1892, without any closing remarks. In spite of its short life the journal should be remembered for the very first publication on the arcuate scotoma, the Bjerrum scotoma from 1889. Although shortlived the initiative was not in vain, as can be read in the preface to the very first volume of Acta ophthalmologica.
Genetic structure and diversity of Shorea obtusa (Dipterocarpaceae) in Thailand
Authors: SENAKUN Chadaporn , CHANGTRAGOON Suchitra , PRAMUAL Pairot , PRATHEPHA Preecha
Published: March 2011

Abstract  Shorea obtusa is a keystone species of the dry deciduous dipterocarp forest in Thailand. In this study, the genetic structure and diversity of this species were evaluated by means of five microsatellite markers. A total of 146 trees were collected from five populations encompassing major forest regions of Thailand. High levels of genetic diversity were found among the five populations with the average He of 0.664. Genetic differentiations between populations, although significant, were low with approximately 3% of genetic variation partitioned among populations. This may indicate that the populations sampled were recently part of a continuous population. A tree constructed using the unweighted pair group method with arithmetic average, based on Nei's genetic distance, divided the populations into three groups. This separation was consistent with the altitudinal zonation of the populations, thus indicating that altitude might play a significant role in the genetic structure of S. obtusa. Areas of high genetic diversity were identified which could be considered priorities for conservation.
Diversity, distribution, and new phylogenetic information of calcareous dinoflagellates from the China Sea
Authors: GU Hai‐Feng , LUO Zhao‐He , WANG Yan , LAN Dong‐Zhao
Published: March 2011

Abstract  Calcareous dinoflagellates have been recorded from subarctic to tropical areas, inhabiting both neritic and oceanic regions. In the present study we analyse 12 sediment samples from the China Sea to establish the existence of calcareous dinoflagellates in this area. A total of 11 calcareous dinoflagellate species were recorded, among them, three genera (Calciodinellum, Leonella, Posoniella) and seven species (Calciodinellum albatrosianum, C. levantinum, C. operosum, Leonella granifera, Posoniella tricarinelloides, Scrippsiella irregularis, and S. regalis) were reported from the China Sea for the first time. Cysts of S. irregularis and S. precaria are identical, with a mesoepicystal archeopyle, representing the loss of 2–4′ and 1–3a paraplates; however, their thecal plates vary slightly and differ from each other in 78 positions of the internal transcribed spacer sequence. Scrippsiella trochoidea is dominant in coastal areas, whereas Calciodinellum albatrosianum is the most abundant offshore. Scrippsiella irregularis is distributed widely along the coast of China, whereas S. precaria is recorded only in northern China. Leonella granifera is the second most abundant species offshore, comprising 15–40% of the cyst assemblage.
Factors influencing long‐term survival and surgical indications for pulmonary metastasectomy for metastases from colorectal cancer
Authors: Yamato Yasushi , Koike Teruaki , Yoshiya Katsuo , Fukui Mariko , Kitahara Akihiko , Toyabe Shin‐ichi
Published: March 2011

Background:  This study examined the prognostic factors and surgical indications for pulmonary metastasectomy for metastases from colorectal cancer.

Methods:  We retrospectively reviewed 142 patients treated between 1985 and 2005 who had undergone complete resections of pulmonary metastases from colorectal cancer.

Results:  Overall 5‐year and 10‐year survival rates were 42.4% and 32.0%, respectively. The 5‐year survival rate for patients with a solitary metastasis was 55.1%, compared with 24.0% for patients with multiple metastases (P= 0.013). The 5‐year survival rate for patients with a disease‐free interval (DFI) ≥ 1000 days was 55.1%, compared with 31.6% for patients with a DFI < 1000 days (P= 0.008). No significant differences in survival rate according to the location of the primary lesion, maximum tumor size, preoperative serum carcinoembryonic antigen level, or surgical procedure were observed. Prior resection for liver metastases and repeated resection for recurrent pulmonary metastases did not influence the survival rate. A multivariate analysis demonstrated that the number of metastases was an independent, significant prognostic factor for survival. The survival rate of patients with three or more metastases was significantly lower than that of patients with two or fewer metastases.

Conclusions:  The number of metastases is an independent prognostic factor after pulmonary metastasectomy for metastases from colorectal cancer. Patients with a solitary pulmonary metastasis benefit the most from pulmonary metastasectomy. The pulmonary resection of three or more metastases is associated with a reduced survival rate. Pulmonary metastasectomy is recommended even for patients with a prior hepatic metastasectomy or patients with recurrent pulmonary metastases.
After shock? Towards a social identity explanation of the Milgram ‘obedience’ studies
Authors: Reicher Stephen , Haslam S. Alexander
Published: March 2011

Russell's forensic archival investigations reveal the great lengths that Milgram went to in order to construct an experiment that would ‘shock the world’. However, in achieving this goal it is also apparent that the drama of the ‘basic’ obedience paradigm draws attention away both from variation in obedience and from the task of explaining that variation. Building on points that Russell and others have made concerning the competing ‘pulls’ that are at play in the Milgram paradigm, this paper outlines the potential for a social identity perspective on obedience to provide such an explanation.
Effect of the Yield to Tensile Ratio on Structural Integrity of Linepipes Subjected to Internal Pressure
Authors: Ernst Hugo A. , Bravo Richard E. , Villasante José A. , Izquierdo Alfonso
Published: March 2011

The effect of the yield (Y) to tensile (T) ratio Y∕T on the structural integrity of linepipes with part through the thickness longitudinal defects subject to internal pressure was studied in this work. A model based on elastic-plastic fracture mechanics and plasticity theory was developed for that purpose. The analysis allows for load or deformation control situations. The results are shown in terms of curves of critical defect size versus the controlling variable, i.e., load or deformation. For each one of the several materials studied, different cases with different Y∕T values were considered. Even for the lower limits of experimental data, i.e., larger Y∕T, the materials have adequate defect tolerance.
Suppression of the Forward Rub in Rotating Machinery by an Asymmetrically Supported Guide
Authors: Inoue Tsuyoshi , Ishida Yukio , Fei Gao , Zahid Hossain Md
Published: March 2011

In rotating machinery, rubbing occurs between the rotor and the stator, at the seal, between the rotor and the guide and between the rotor and the backup bearing. The backward rub or the partial impact vibration can be avoided by lubricating the contact surface sufficiently in order to decrease the friction. However, forward rub may still occur in such a case with a lubricated contact surface. Once such a forward rub occurs, it remains even if the rotational speed increases to much larger than the first bending critical speed and it is difficult to escape from this forward rubbing condition automatically. This paper proposes the suppression method of this forward rub by introducing the directional difference in the support stiffness of the guide or the backup bearing. The nonlinear theoretical analysis clarifies and explains the usefulness of the proposed method and it is also validated experimentally.
Eigenfrequency Computation of Beam/Plate Carrying Concentrated Mass/Spring
Authors: Zhang Yin
Published: March 2011

With the adsorption of analyte on the resonator mass sensor, the system eigenfrequencies will shift due to the changes of inertial mass and structural rigidity. How to model those changes and formulate the eigenfrequency computation is very important to the mass sensor application, which results in different accuracies and requires different amounts of computation. Different methods on the eigenfrequency computation of a beam and a plate carrying arbitrary number of concentrated mass/spring are presented and compared. The advantages and disadvantages of these methods are analyzed and discussed. A new method called finite mode transform method (FMTM) is shown to have good convergence and require much less computation for a beam carrying concentrated mass/spring. Because the previous finite sine transform method (FSTM) has only been applied to compute the eigenfrequency of the plate with four edges simply supported carrying a single concentrated mass, here a generalized FSTM is also presented for the case of the same plate carrying arbitrary number of concentrated mass and spring. When the total number of concentrated mass and spring is small, FMTM and FSTM are demonstrated to be very efficient.
SOFC Management in Distributed Energy Systems
Authors: Chiappini Daniele , Facci Andrea Luigi , Tribioli Laura , Ubertini Stefano
Published: March 2011

Among the distributed generation emerging technologies, solid oxide fuel cells (SOFCs) seem to be the most promising for small and medium power (up to 1 MW) as they feature extremely high efficiency and low pollutant emissions, and the high-grade waste heat can be utilized for space heating, process steam, and/or domestic hot water demands. As their main drawbacks are high cost and relatively short lifetime, much research is devoted to solve technological problems and to develop less expensive materials and mass production processes. However, even if SOFCs are close to commercialization and several demonstration units are already running, only few researches have been performed on their integration in power plants for distributed power generation, which are complex systems made up of different components that have to satisfy energy requirements (heat, electricity, and cooling). In this paper, we investigate the behavior of SOFCs in distributed energy systems and how their operation in terms of load and fuel utilization factor could optimize fuel consumption and/or minimize energy costs. The potential advantages of SOFCs related to their excellent part-load operation and their ability to meet and follow the highly noncoincident electric and thermal loads in either grid-connected or stand-alone configurations are discussed.
Nonlinear Amplitude-Frequency Response of a Helmholtz Resonator
Authors: Yu G. K. , Zhang Y. D. , Shen Y.
Published: March 2011

Nonlinear amplitude-frequency response of an acoustic Helmholtz resonator is investigated by incorporating linear damping, nonlinear damping, and nonlinear restoration. Method of multiple time scale is used for theoretical analysis, and a reasonable explanation of an experiment observation, i.e., the downward shift of resonance frequency, is given. We also discuss the response of two-frequency driving, and find that amplitude-frequency response depends on the phase difference of the driving. In addition, the response amplitude of two-frequency driving can increase approximately 10% as compared with the single frequency driving at a certain phase difference for the parameters we choose to simulate.
Determination of Modal Parameters in Complex Nonlinear Systems
Authors: Skjoldan Peter F. , Bauchau Olivier A.
Published: March 2011

This paper describes a methodology for evaluating the modal parameters of complex nonlinear systems. It combines four different tools: the Coleman post-processing, the partial Floquet analysis, the moving window analysis, and the signal synthesis algorithm. The approach provides a robust estimation of the linearized modal parameters and qualitative information about the nonlinear behavior of the system. It operates on one or multiple discrete time signals and is able to deal with both time-invariant and periodic systems. The method is computationally inexpensive and can be used with multiphysics computational tools, and in principle, with experimental data. The proposed approach is validated using a simple, four degree of freedom model of a wind turbine. The predictions for the linear system are validated against an exact solution of the problem. For the nonlinear system, it is demonstrated that qualitative information concerning the nonlinear behavior of the system is obtained using the proposed method. Finally, the nonlinear behavior of a realistic, three-bladed horizontal axis wind turbine model is investigated.
Finite Element Analysis of Welding Processes by Way of Hypoelasticity-Based Formulation
Authors: Han You Sung , Lee Kyehyung , Han Myoung-Soo , Chang Hyunchil , Choi Kanghyouk , Im Seyoung
Published: March 2011

Welding is one of the most important joining processes, and the effect of welding residual stresses in a structure has a great deal of influence on its quality. In spite of such a key interest, the analysis of a welding process has not been successful as in a structural analysis. This is partially because welding involves complex phenomena that are manifested by the phase evolution and by thermomechanical processes as well. In the present study, a hypoelasticity-based formulation is applied to welding processes to determine residual deformation and stresses. Algorithmic consistent moduli for elastoplastic deformations including transformation plasticity are also obtained. Leblond’s phase evolution equation, coupled with the energy equation, is employed to calculate the phase volume fraction; this plays an important role as a constitutive parameter reflecting phase fraction effects in a mechanical constitutive equation. Furthermore, transformation plasticity is taken into account for an accurate evaluation of stress. The influence of the phase transformation and the transformation plasticity on residual stress is investigated by means of numerical analyses using metallurgical parameters in Leblond’s phase evolution equation that are adjusted with respect to various cooling rates in a CCT-diagram. Coding implementation is conducted by way of the ABAQUS user subroutines, DFLUX, UEXPAN, and UMAT. The numerical examples demonstrated that the phase transformation and the transformation plasticity have a significant effect on the residual stress of a welded structure.
Processing of Small Scale Nitinol Billets by Induction Heated Nonconventional Isothermal Extrusion (IHNCIE)
Authors: Butler J. , Tiernan P. , Gandhi A. A. , Beloshapkin S. , Tofail S. A. M.
Published: March 2011

This paper describes a novel process designed specifically for extruding small scale billets, between 850°C and 950°C, in very short cycle times of 10 min. Induction heated nonconventional isothermal extrusion (IHNCIE) is used to produce wires of Nitinol and compare its efficacy with wires produced conventionally by hot rolling. With two four to one area reductions, a wire of 3 mm diameter was formed by IHNCIE. The extruded wires showed good superelastic tensile properties. This 3 mm diameter extruded wire exhibited a microstructure with grains of approximately 2 μm without a recrystallization anneal. Our method offers an alternative route for the production of small scale billets into a wire.
Generalized Grünwald–Letnikov Fractional Derivative and Its Laplace and Fourier Transforms
Authors: Ortigueira Manuel D. , Trujillo Juan J.
Published: March 2011

The generalized Grünwald–Letnikov fractional derivative is analyzed in this paper. Its Laplace and Fourier transforms are computed, and some current results are criticized. It is shown that only the forward derivative of a sinusoid exists. This result is used to define the frequency response of a fractional linear system.
Geometrical Effects on the Temperature Distribution in a Half-Space Due to a Moving Heat Source
Authors: Akbari Mohsen , Sinton David , Bahrami Majid
Published: March 2011

Fundamental problem of heat transfer within a half-space due to a moving heat source of hyperelliptical geometry is studied in this work. The considered hyperelliptical geometry family covers a wide range of heat source shapes, including star-shaped, rhombic, elliptical, rectangular with round corners, rectangular, circular, and square. The effects of the heat source speed, aspect ratio, corners, and orientation are investigated using the general solution of a moving point source on a half-space and superposition. Selecting the square root of the heat source area as the characteristics length scale, it is shown that the maximum temperature within the half-space is a function of the heat source speed (Peclet number) and its aspect ratio. It is observed that the details of the exact heat source shape have negligible effect on the maximum temperature within the half-space. New general compact relationships are introduced that can predict the maximum temperature within the half-space with reasonable accuracy. The validity of the suggested relationships is examined by available experimental and numerical data for the grinding process, for medium Peclet numbers. For ultrafast heat sources, an independent experimental study is performed using a commercial CO2 laser system. The measured depth of the engraved grooves is successfully predicted by the proposed relationships.
Review on the Properties of Nano-/Microstructures in the Catalyst Layer of PEMFC
Authors: Yu Xiao , Yuan Jinliang , Sundén Bengt
Published: March 2011

The catalyst layer (CL) of a proton exchange membrane fuel cell involves various particles and pores that span a wide range of length scales, from several nanometers to a few microns. The success of the CL design depends decisively on understanding the detailed structure in microscale or even in nanoscale. In this paper, the properties of nano-/microstructures are outlined, and the physical and chemical processes are analyzed on the Pt surfaces. A software package of automatic simulation environment is developed and applied to investigate the electronic structure of the Pt–H system. Then, the H2 dissociative adsorption process is obtained using the nudged elastic band approach. The modeling of the nanocomposites in the CLs is a multiscale problem. The nanoscale models are used for investigating the structural evolution and the interactions between Pt/C particles and polymer components; while the microscale simulations, which aim to bridge molecular methods and continuum methods, are extended to describe the morphology of heterogeneous materials and rationalize their effective properties beyond length- and time-scale limitations of the atomistic simulations. However, there are still some major challenges and limitations in these modeling and simulations. The multiscale modeling should be developed to demonstrate the usefulness for engineering design with the longstanding goal of predicting particle-structure-property.
Dynamics and Control of a Small-Scale Boom Crane
Authors: Maleki Ehsan , Singhose William
Published: March 2011

Cranes are vital to many manufacturing and material-handling processes. However, their physical structure leads to flexible dynamic effects that limit their usefulness. Large payload swings induced by either intentional crane motions or external disturbances decrease positioning accuracy and can create hazardous situations. Boom cranes are one of the most dynamically complicated types of cranes. Boom cranes cannot transfer the payload in a straight line by actuating only one axis of motion because they have rotational joints. This paper presents a nonlinear model of a boom crane. A large range of possible motions is analyzed to investigate the dynamic behavior of the crane when it responds to operator commands. A command-shaping control technique is implemented, and its effectiveness on this nonlinear machine is analyzed. Experimental results verify key theoretical predictions.
Nonlinear Aeroelastic Analysis of Bending-Torsion Wings Subjected to a Transverse Follower Force
Authors: Fazelzadeh S. A. , Mazidi A.
Published: March 2011

This paper deals with the nonlinear aeroelastic behaviors of bending-torsion wings subjected to a transverse follower force. The nonlinear structural wing formulation is based on von Karman large deformation theory. In order to accurately consider the spanwise location of the follower force, the generalized function theory is used. Also, Peter’s finite-state unsteady aerodynamic model is considered. The governing equations are obtained using Hamilton’s principle. Furthermore, the Galerkin method is applied to convert the partial differential equations into a set of nonlinear ordinary differential equations, which will be solved through the numerical integration scheme. Wing dynamic behaviors are investigated through frequency spectra and the bifurcation diagrams of Poincaré maps. In addition, the postcritical region, which includes all periodic, quasiperiodic, and chaotic pockets, is indeed found to exist. Furthermore, the results indicate noticeable effects of the follower force magnitude and location as well as the air stream velocity on critical and postcritical behaviors of a wing.
Reliability Based Design Optimization Using a Single Constraint Approximation Point
Authors: Dersjö Tomas , Olsson Mårten
Published: March 2011

The computational effort for reliability based design optimization (RBDO) is no longer prohibitive even for detailed studies of mechanical integrity. The sequential approximation RBDO formulation and the use of surrogate models have greatly reduced the amount of computations necessary. In RBDO, the surrogate models need to be most accurate in the proximity of the most probable point. Thus, for multiply constrained problems, such as fatigue design problems, where each finite element (FE)-model node constitutes a constraint, the computational effort may still be considerable if separate experiments are used to fit each constraint surrogate model. This paper presents an RBDO algorithm that uses a single constraint approximation point (CAP) as a starting point for the experiments utilized to establish all surrogate models, thus reducing the computational effort to that of a single constraint problem. Examples of different complexities from solid mechanics applications are used to present the accuracy and versatility of the proposed method. In the studied examples, the ratio of the computational effort (in terms of FE-solver calls) between a conventional method and the single CAP algorithm was approximately equal to the number of constraints and the introduced error was small. Furthermore, the CAP-based RBDO is shown to be capable of handling over 10,000 constraints and even an intermittent remeshing. Also, the benefit of considering other objectives than volume (mass) is shown through a cost optimization of a truck component. In the optimization, fatigue-specific procedures, such as shot peening and machining to reduce surface roughness, are included in the cost as well as in the constraints.
A Semi-Empirical Model for Condensation Heat Transfer Coefficient of Mixed Ethanol-Water Vapors
Authors: Li Yang , Yan JunJie , Wang JinShi , Wang GuoXiang
Published: March 2011

A semi-empirical model describing the heat transfer characteristics of the pseudo-dropwise condensation of binary vapor on a cooled vertical tube has been formulated. By ignoring the thin film always present on the condensation surface and the intensification of mass transfer caused by the Marangoni effect, the heat transfer characteristics of pseudo-dropwise condensation are tentatively formulated. The model involved an analysis of the diffusion process in the vapor boundary layer along with the heat transfer process through the condensate drops. This model was applied to the condensation of the saturated binary vapor of ethanol and water, and was examined using experimental data at vapor pressure values of 101.33 kPa (provided by Utaka and Wang, 2004, “Characteristic Curves and the Promotion Effect of Ethanol Addition on Steam Condensation Heat Transfer,” Int. J. Heat Mass Transfer, 47, pp. 4507–4516), 84.52 kPa and 47.36 kPa. Calculations using the model show a similar trend to the experimental measurements. With the change of the vapor-to-surface temperature difference, the heat transfer coefficients revealed nonlinear characteristics, with the peak values under all ethanol mass fractions of binary vapor. The heat transfer coefficients increased with decreasing ethanol mass fraction.
Mathematical Modeling of Transport Processes in Funnel Shaped Mold of Steel Thin Slab Continuous Caster
Authors: Hajari A. , Seyedein S. H. , Aboutalebi M. R.
Published: March 2011

In this work a three-dimensional fluid flow and heat transfer model was developed to predict the flow pattern and superheat dissipation in funnel shaped mold of a thin slab continuous caster with a novel tetrafurcated design for the submerged entry nozzle. Low Reynolds k−ε turbulent model was adopted to account for the turbulent effect. The transport equations were solved numerically using finite volume method. The results were compared with a full scale water model of the caster. Good agreement between mathematical and physical models was obtained. Parametric studies were carried out to evaluate the effect of casting speed, nozzle submergence depth, and inlet temperature on the superheat dissipation, flow pattern, and surface turbulence in the mold region. The results indicate a special flow pattern and heat distribution in the caster while using a tetrafurcated nozzle. Aiming to achieve more product capacity, in the case of casting with lower superheat temperature, a higher casting speed, together with higher submergence depth, is recommended in order to avoid surface turbulence and high heat flux across the narrow face.
On the Scalability of Liquid Microjet Array Impingement Cooling for Large Area Systems
Authors: Bhunia Avijit , Chen C. L.
Published: March 2011

The necessity for an efficient thermal management system covering large areas is growing rapidly with the push toward more electric systems. A significant amount of research over the past 2 decades has conclusively proved the suitability of jet, droplet, or spray impingement for high heat flux cooling. However, all these research consider small heat source areas, typically about a few cm2. Can a large array of impingement pattern, covering a much wider area, achieve similar heat flux levels? This article presents liquid microjet array impingement cooling of a heat source that is about two orders of magnitude larger than studied in the previous works. Experiments are carried out with 441 jets of de-ionized water and a dielectric liquid HFE7200, each 200 μm diameter. The jets impinge on a 189 cm2 area surface, in free surface and confined jet configurations. The average heat transfer coefficient values of the present experiment are compared with correlations from the literature. While some correlations show excellent agreement, others deviate significantly. The ensuing discussion suggests that the post-impingement liquid dynamics, particularly the collision between the liquid fronts on the surface created from surrounding jets, is the most important criterion dictating the average heat transfer coefficient. Thus, similar thermal performance can be achieved, irrespective of the length scale, as long as the flow dynamics are similar. These results prove the scalability of the liquid microjet array impingement technique for cooling a few cm2 area to a few hundred cm2 area.
CFD Investigating the Effects of Different Mixing Vane Designs on the Localized Thermal-Hydraulic Characteristics in the Rod Bundles With Grid Spacer
Authors: Liu C. C. , Ferng Y. M. , Shih C. K. , Pei B. S.
Published: March 2011

A safe and reliable operation of a reactor system relies on the accurate thermal-hydraulic design in the rod bundles. With the dramatic progress in the computer processing power, computational fluid dynamics (CFD) methodology can be applied in investigating these thermal-hydraulic characteristics in details. The flow mixing devices on a grid spacer are generally designed to enhance the turbulence and heat transfer in the sub-channels. Therefore, the majority of this paper is to investigate the effects of different mixing vane configurations on flow pattern and heat transfer in the downstream of the mixing vanes in the rod bundles through CFD methodology. This CFD model is first assessed by the previous experiment of Holloway et al. In this study, six different designs of split-vane pairs are simulated, including (a) the split-vane 1 pairs (b) the split-vane 1 pairs without weld-nugget (c) the split-vane 2 pairs without weld-nugget (d) the Hybrid vane (e) the Swirl vane and (f) the SSVF vane. The thermal-hydraulic characteristics within the rod bundles with the split-vane pairs can be reasonably captured by the present CFD model, which includes the swirling secondary flow, turbulent mixing increase, and heat transfer enhancement, etc. Based on the comparison of Nusselt number distribution downstream the grid, the design of split-vane 1 pairs can enhance the heat transfer capability than other vane designs.