bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of Amplitude-Based and Phase-Based Methods for Speed Tracking in Application to Wind Turbines
Authors: Urbanek Jacek , Barszcz Tomasz , Sawalhi Nader , Randall Robert
Published: June 2011

Comparison of Amplitude-Based and Phase-Based Methods for Speed Tracking in Application to Wind Turbines

Focus of the vibration expert community shifts more and more towards diagnosing machines subjected to varying rotational speeds and loads. Such machines require order analysis for proper fault detection and identification. In many cases phase markers (tachometers, encoders, etc) are used to help performing the resampling of the vibration signals to remove the speed fluctuations and smearing from the spectrum (order tracking). However, not all machines have the facility to install speed tracking sensors, due to design or cost reasons, and the signal itself has to then be used to extract this information. This paper is focused on the problem of speed tracking in wind turbines, which represent typical situations for speed and load variation. The basic design of a wind turbine is presented. Two main types of speed control i.e. stall and pitch control are presented,. The authors have investigated two methods of speed tracking, using information from the signal (without relying on a speed signal). One method is based on extracting a reference signal to use as a tachometer, while the other is phase-based (phase demodulation). Both methods are presented and applied to the vibration data from real wind turbines. The results are compared with each other and with the actual speed data.
Inductive Sensor for Weighing of Mass
Authors: Lewandowski Janusz
Published: June 2011

Inductive Sensor for Weighing of Mass

A new method measuring of mass in electronic system of scales has been described. The main element of this system is inductive measuring load cell, which was compared with strain gauge load cell. The aim of the paper is described advantages of the inductive measuring system of mass and explain some main problems of this system. Digital correction of the mechanical errors of the beam like: hysteresis, creep material of the beam under constant load, influence of ambient temperature was described.
Investigation of the Statistical Method of Time Delay Estimation Based on Conditional Averaging of Delayed Signal
Authors: Kowalczyk Adam , Hanus Robert , Szlachta Anna
Published: June 2011

Investigation of the Statistical Method of Time Delay Estimation Based on Conditional Averaging of Delayed Signal

This paper presents the results of the theoretical and practical analysis of selected features of the function of conditional average value of the absolute value of delayed signal (CAAV). The results obtained with the CAAV method have been compared with the results obtained by method of cross correlation (CCF), which is often used at the measurements of random signal time delay. The paper is divided into five sections. The first is devoted to a short introduction to the subject of the paper. The model of measured stochastic signals is described in Section 2. The fundamentals of time delay estimation using CCF and CAAV are presented in Section 3. The standard deviations of both functions in their extreme points are evaluated and compared. The results of experimental investigations are discussed in Section 4. Computer simulations were used to evaluate the performance of the CAAV and CCF methods. The signal and the noise were Gaussian random variables, produced by a pseudorandom noise generator. The experimental standard deviations of both functions for the chosen signal to noise ratio (SNR) were obtained and compared. All simulation results were averaged for 1000 independent runs. It should be noted that the experimental results were close to the theoretical values. The conclusions and final remarks were included in Section 5. The authors conclude that the CAAV method described in this paper has less standard deviation in the extreme point than CCF and can be applied to time delay measurement of random signals.
Pathological effects and motor response threshold changes following radiofrequency application at various distances from the L-5 nerve root: an experimental study
Authors: Maarrawi Joseph , Kobaiter-Maarrawi Sandra , Ghanem Ismat , Ali Youssef , Aftimos Georges , Okais Nabil , Samaha Elie
Published: June 2011

Object

Radiofrequency (RF) ablation is a minimally invasive technique often used percutaneously in the treatment of many conditions such as spasticity, pain, and osteoid osteoma. The purpose of this study was to assess the value of motor response threshold (MRT) as an indirect indicator of the RF generator's electrode to nerve distance, and to evaluate the effects of RF at various distances from a nervous structure.

Methods

The L-5 nerve root was studied in 102 Sprague-Dawley rats (sham contralateral side). Motor response thresholds at 0, 2, 4, 5, and 6 mm from the nerve root were assessed before and after RF application for 2 minutes at 80° C on Days 0 and 7. Radiofrequency was applied 0, 2, 4, 5, and 6 mm away from L-5 and with the addition of interposed cortical bone. The effects of RF application on MRT were studied, and subsequent nerve injury was evaluated using light microscopy pathological examination.

Results

There is a significant correlation between MRT and the distance between the electrode tip and L-5, with MRT less than 0.5 V when the electrode was in direct contact with the root. Electrical and pathological changes following RF application were more pronounced at 0 mm, with worsening seen on Day 7. Radiofrequency at 2 and 4 mm produced fewer electrical and histological deleterious effects on the nerve on Days 0 and 7, with an obvious improvement on Day 7. At 5 mm, electrical and histological abnormalities were minimal on Day 0 and were fully reversible on Day 7. At 6 mm and with interposed cortical bone, MRT and pathological findings were unchanged on Days 0 and 7.

Conclusions

The MRT proved to be a useful and reliable tool in decreasing nerve morbidity following RF ablation in animals and may be used in humans for the same purpose. It serves as an indirect indicator of the proximity of the RF generator's electrode tip to any adjacent motor nervous structure. A minimum safe distance of 5 mm between the electrode tip and the nerve is required to avoid irreversible nerve injury, unless a bony wall is interposed between them, thus serving as a nerve shield. In medical conditions that require RF ablation of the nerve, such as spasticity and pain, the MRT must be lower than 0.5 V. When a nerve lesion is to be avoided such as in cases of osteoid osteoma, an MRT higher than 2.5 V is considered safe, reflecting a distance greater than 5 mm.
Risk factors for posttraumatic vasospasm
Authors: Shahlaie Kiarash , Keachie Krista , Hutchins Irene M. , Rudisill Nancy , Madden Lori K. , Smith Karen A. , Ko Karen A. , Latchaw Richard E. , Muizelaar J. Paul
Published: June 2011

Object

Posttraumatic vasospasm (PTV) is an underrecognized cause of ischemic damage after severe traumatic brain injury (TBI) that independently predicts poor outcome. There are, however, no guidelines for PTV screening and management, partly due to limited understanding of its pathogenesis and risk factors.

Methods

A database review of 46 consecutive cases of severe TBI in pediatric and adult patients was conducted to identify risk factors for the development of PTV. Univariate analysis was performed to identify potential risk factors for PTV, which were subsequently analyzed using a multivariate logistic regression model to calculate odds ratios (ORs) and 95% confidence intervals (CIs).

Results

Fever on admission was an independent risk factor for development of PTV (OR 22.2, 95% CI 1.9–256.8), and patients with hypothermia on admission did not develop clinically significant vasospasm during their hospital stay. The presence of small parenchymal contusions was also an independent risk factor for PTV (OR 7.8, 95% CI 0.9–69.5), whereas the presence of subarachnoid hemorrhage or other patterns of intracranial injury were not. Other variables, such as age, sex, ethnicity, degree of TBI severity, or admission laboratory values, were not independent predictors for the development of clinically significant PTV.

Conclusions

Independent risk factors for PTV include parenchymal contusions and fever. These results suggest that diffuse mechanical injury and activation of inflammatory pathways may be underlying mechanisms for the development of PTV, and that a subset of patients with these risk factors may be an appropriate population for aggressive screening. Further studies are needed to determine if treatments targeting fever and inflammation may be effective in reducing the incidence of vasospasm following severe TBI.
Notch receptor and effector expression in von Hippel-Lindau disease–associated central nervous system hemangioblastomas
Authors: Merrill Marsha J. , Edwards Nancy A. , Lonser Russell R.
Published: June 2011

Object

Central nervous system hemangioblastomas are the most common manifestation of von Hippel-Lindau (VHL) disease, an autosomal dominant tumor suppressor syndrome that results in loss of VHL protein function and continuous upregulation of hypoxia-inducible factors. These tumors are composed of neoplastic stromal cells and abundant vasculature. Stromal cells express markers consistent with multipotent embryonically arrested hemangioblasts, which are precursors for hematopoietic and vascular lineages. Notch receptors are transmembrane signaling molecules that regulate multiple developmental processes including hematopoiesis and vasculogenesis. To investigate the importance of notch signaling in the development of VHL disease–associated CNS hemangioblastomas, the authors examined the presence of the four notch receptors and downstream notch effectors in this setting.

Methods

The authors used surgical specimens obtained from confirmed VHL-associated hemangioblastomas. Immunohistochemical analysis for the four notch receptors and the downstream effectors was performed on formalin-fixed paraffin-embedded sections. Western blot analysis for HES1 was performed on frozen specimens.

Results

All four notch receptors are present in hemangioblastomas. NOTCH1 and NOTCH4 receptors were widely and prominently expressed in both the stromal and vascular cells, NOTCH2 receptor expression was limited to primarily stromal cells, and NOTCH3 receptor expression was limited to vascular cells. All 4 receptors displayed a nuclear presence. Immunohistochemical analysis also demonstrated that downstream notch effectors, HES1 and HES5, were uniformly expressed in tumor stromal and vascular cells, but HES3, HEY1, and HEY2 were not. Strong HES1 expression was confirmed by Western blot analysis.

Conclusions

The presence of all four notch receptors and downstream effector molecules suggests that the notch signaling pathway plays a critical role in the maintenance of the undifferentiated pluripotent phenotype of these tumors and in the associated vascular response. Moreover, the prominent expression of notch receptors in VHL-associated CNS hemangioblastomas reveals a new and possibly potent therapeutic target.
Protective Role of α2HS-Glycoprotein in HBV-Associated Liver Failure
Authors: Dai Xia-Hong , Zhang Pan , Xiao Mei-Fang , Zhou Rong-Rong , Zhang Bao-Xin , Hu Guan-Sheng , Huang Ze-Bing , Fan Xue-Gong
Published: June 2011

n this study, levels of plasma α2-Heremans-Schmid glycoprotein, serum tumor necrosis factor-α, serum liver function parameters and short-term mortality were measured in 100 hepatitis B patients. Release of interleukin-6 and tumor necrosis factor-α from the lipopolysaccharide-stimulated peripheral blood mononuclear cells in the presence/absence of spermine and α2-Heremans-Schmid glycoprotein were analyzed by enzyme-linked immunosorbent assay to determine the significance and potential mechanism of α2-Heremans-Schmid glycoprotein in hepatitis B virus-associated liver damage. Results showed that serum α2-Heremans-Schmid glycoprotein levels in acute-on-chronic liver failure patients were significantly lower than that in chronic hepatitis B patients or healthy controls (p < 0.05). A negative dependence between serum human α2-Heremans-Schmid glycoprotein and tumor necrosis factor-α levels was observed. Interleukin-6 and tumor necrosis factor-α levels in the lipopolysaccharide-induced peripheral blood mononuclear cell supernates were significantly reduced by spermine and/or α2-Heremans-Schmid glycoprotein. The latter two proteins jointly inhibited cytokine release. These observations suggest that plasma α2-Heremans-Schmid glycoprotein is an independent marker of liver damage and a prognostic indicator of hepatitis B virus chronicity. It may reduce liver inflammation by partially inhibiting release of inflammatory factors from activated peripheral blood mononuclear cells.
Butin (7,3′,4′-Trihydroxydihydroflavone) Reduces Oxidative Stress-Induced Cell Death via Inhibition of the Mitochondria-Dependent Apoptotic Pathway
Authors: Zhang Rui , Lee In Kyung , Piao Mei Jing , Kim Ki Cheon , Kim Areum Daseul , Kim Hye Sun , Chae Sungwook , Kim Hee Sun , Hyun Jin Won
Published: June 2011

Recently, we demonstrated that butin (7,3′,4′-trihydroxydihydroflavone) protected cells against hydrogen peroxide (H2O2)-induced apoptosis by: (1) scavenging reactive oxygen species (ROS), activating antioxidant enzymes such superoxide dismutase and catalase; (2) decreasing oxidative stress-induced 8-hydroxy-2'-deoxyguanosine levels via activation of oxoguanine glycosylase 1, and (3), reducing oxidative stress-induced mitochondrial dysfunction. The objective of this study was to determine the cytoprotective effects of butin on oxidative stress-induced mitochondria-dependent apoptosis, and possible mechanisms involved. Butin significantly reduced H2O2-induced loss of mitochondrial membrane potential as determined by confocal image analysis and flow cytometry, alterations in Bcl-2 family proteins such as decrease in Bcl-2 expression and increase in Bax and phospho Bcl-2 expression, release of cytochrome c from mitochondria into the cytosol and activation of caspases 9 and 3. Furthermore, the anti-apoptotic effect of butin was exerted via inhibition of mitogen-activated protein kinase kinase-4, c-Jun NH2-terminal kinase (JNK) and activator protein-1 cascades induced by H2O2 treatment. Finally, butin exhibited protective effects against H2O2-induced apoptosis, as demonstrated by decreased apoptotic bodies, sub-G1 hypodiploid cells and DNA fragmentation. Taken together, the protective effects of butin against H2O2-induced apoptosis were exerted via blockade of membrane potential depolarization, inhibition of the JNK pathway and mitochondria-involved caspase-dependent apoptotic pathway
Inorganic-Organic Hybrid Nanomaterials for Therapeutic and Diagnostic Imaging Applications
Authors: Vivero-Escoto Juan L. , Huang Yu-Tzu
Published: June 2011

Nanotechnology offers outstanding potential for future biomedical applications. In particular, due to their unique characteristics, hybrid nanomaterials have recently been investigated as promising platforms for imaging and therapeutic applications. This class of nanoparticles can not only retain valuable features of both inorganic and organic moieties, but also provides the ability to systematically modify the properties of the hybrid material through the combination of functional elements. Moreover, the conjugation of targeting moieties on the surface of these nanomaterials gives them specific targeted imaging and therapeutic properties. In this review, we summarize the recent reports in the synthesis of hybrid nanomaterials and their applications in biomedical areas. Their applications as imaging and therapeutic agents in vivo will be highlighted.
The Immuno-Regulatory Effects of Schisandra chinensis and Its Constituents on Human Monocytic Leukemia Cells
Authors: Lin Rong-Dih , Mao Yi-Wen , Leu Sy-Jye , Huang Ching-Yi , Lee Mei-Hsien
Published: June 2011

Many diseases occur when the immune system is weakened. Intracellular signals activate immuno-responsive cells to produce cytokines that modulate the immune response. Schisandra chinensis has been used traditionally to treat general fatigue, neurasthenia, and spontaneous sweating. In the present study, the effect of constituents of S. chinensis on cytokine release by human monocytic leukemia cells (THP-1) was tested using microparticle-based flow cytometric analysis. Two major lignans, schizandrin (Sch) and gomisin A (Gom A), were identified and shown to induce interleukin (IL)-8, macrophage inflammatory protein-1β (MIP-1β), and granulocyte-macrophage-colony stimulating factor (GM-CSF) release by THP-1 cells. By reverse transcription polymerase chain reaction (RT-PCR) or quantitative real-time PCR, there was a dose-dependent increase of IL-8, MIP-1β and GM-CSF mRNA levels. Thus, Sch and Gom A from S. chinensis enhance cytokine release by THP-1 cells and this effect occurs through mRNA upregulation. Upregulation of MIP-1β and GM-CSF in particular may have clinical applications. Therefore, S. chinensis may be therapeutically beneficial by promoting humoral and cell-mediated immune responses.
Synthetic Studies on Bioactive Natural Polyketides: Intramolecular Nitrile Oxide-Olefin Cycloaddition Approach for Construction of a Macrolactone Skeleton of Macrosphelide B
Authors: Paek Seung-Mann , Suh Young-Ger
Published: June 2011

Studies on the synthesis of macrosphelide B via an intramolecular nitrile oxide-olefin cycloaddition (INOC) is described. In particular, an asymmetric INOC approach using phase transfer catalysts seems to be a potentially efficient and versatile procedure for the construction of the macrolactone skeleton of macrosphelide B in terms of facial selectivity. Our preliminary and unprecedented stereoselective procedure is anticipated to be usefully applied through further studies for the synthesis of the macrosphelide family.
Human T-Cell Lymphotropic Virus: A Model of NF-κB-Associated Tumorigenesis
Authors: Qu Zhaoxia , Xiao Gutian
Published: June 2011

Human T-cell lymphotropic virus type 1 (HTLV-1) is the etiological agent of adult T-cell leukemia/lymphoma (ATL), whereas the highly related HTLV-2 is not associated with ATL or other cancers. In addition to ATL leukemogenesis, studies of the HTLV viruses also provide an exceptional model for understanding basic pathogenic mechanisms of virus-host interactions and human oncogenesis. Accumulating evidence suggests that the viral regulatory protein Tax and host inflammatory transcription factor NF-kB are largely responsible for the different pathogenic potentials of HTLV-1 and HTLV-2. Here, we discuss the molecular mechanisms of HTLV-1 oncogenic pathogenesis with a focus on the interplay between the Tax oncoprotein and NF-κB pro-oncogenic signaling. We also outline some of the most intriguing and outstanding questions in the fields of HTLV and NF-κB. Answers to those questions will greatly advance our understanding of ATL leukemogenesis and other NF-κB-associated tumorigenesis and will help us design personalized cancer therapies.
Managing Water in a Changing World
Authors: Cassardo Claudio , Jones J. Anthony A.
Published: June 2011

Water, being a primary element in the diet and a necessary resource for the agriculture, can be considered a basic need for humans. In addition, also industrial practices need a growing amount of water. Since human population is continuously growing at a rate that, in the last two centuries, approximates well the exponential, water demand is increasing. However, the water resources on the Earth are finite. For this reason, even disregarding the potential threats due to the climate change, this situation appears as one of the biggest challenges of the current era. Actually, several small-scale regions already face water sustainability problems, and the scarcity of water resources is expected to spread to wider areas in the near future, if the actual trends of development and population growth do not change. The situation is exacerbated as the climate is already changing, due to the anthropogenic emissions of greenhouse gases in the atmosphere, and its rate is expected to increase by the end of this century. The effects of these changes will increase the natural variability of the climate, exacerbating the extreme climatic phenomena (drought and flood events) and increasing the difficulty of managing water resources, especially in the most vulnerable regions.
Use of Intranasal Medications in Pediatric Patients
Authors: Warrington Susan E. , Kuhn Robert J.
Published: June 2011

A growing body of evidence supports the intranasal administration of atomized medications for a wide variety of pediatric indications. This article describes their use applicable to orthopedic specialists in the areas of pediatric pain management, as well as pre- and intraoperative sedation. As a quick, painless alternative to more invasive routes of administration, intranasal drug delivery has shown similar time to clinical effect compared to the intravenous route, while minimizing anxiety in both patients and their parents.
Analysis of the Trauma Section of the Orthopaedic In-Training Examination
Authors: Taylor Benjamin C. , Fowler T. Ty
Published: June 2011

The Orthopaedic In-Training Examination is a comprehensive test produced annually by the American Academy of Orthopaedic Surgeons, and was first administered in 1963. At the time of the examination’s conception, its objectives were to: (1) measure the knowledge of orthopedic residents and provide objective comparisons; (2) help determine acceptable minimal standards for trainees; and (3) help provide an objective assessment of orthopedic education. We retrospectively reviewed all Orthopaedic In-Training Examinations from 2004 to 2008, with particular focus on the questions listed in the musculoskeletal trauma domain on each year’s program director report. The musculoskeletal trauma domain, including topics, recommended answers, and references, was reviewed to provide an educational resource for residents and residency programs when studying or designing educational curricula. The information in this analysis may help in development of a core musculoskeletal trauma knowledge base or facilitate determination of appropriate journal club and didactic lecture content.
Treatment of Complex Tibial Fractures in Children with the Taylor Spatial Frame
Authors: Eidelman Mark , Katzman Alexander
Published: June 2011

Most tibial shaft fractures in children can be treated with closed reduction and cast fixation, but some fractures need external or internal fixation. The Taylor spatial frame (Smith & Nephew, Memphis, Tennessee) is a relatively new external fixator that can correct 6-axis deformities with computer accuracy. This article reports our experience using the Taylor spatial frame as a rewarding treatment modality for complex tibial fractures in children and adolescents.
Effect of Timing and Duration of Tamsulosin Exposure on Complications in Resident-Performed Phacoemulsification
Authors: Ku Tina K. , Naseri Ayman , Han Ying , Porco Travis C. , Rutar Tina
Published: June 2011

BACKGROUND AND OBJECTIVES:

Tamsulosin can cause intraoperative floppy iris syndrome and increase the risk of phacoemulsification complications. This study evaluated whether the risk of complications was associated with the timing or duration of preoperative tamsulosin exposure.

PATIENTS AND METHODS:

The current study was a retrospective review of electronic medical records of resident-performed phacoemulsification surgeries from 1998 to 2008 at a Veterans Administration Hospital. There were 73 eyes with recent tamsulosin exposure (within 30 days preoperatively) and 28 eyes with remote exposure (> 30 days preoperatively but within 3 years of surgery).

RESULTS:

There was a trend toward more total complications in recent compared with remote tamsulosin exposure cases (31.5% vs 14.3%,
P
= .09). A longer duration of tamsulosin use was not statistically associated with an increased risk of total complications.

CONCLUSION:

The authors were unable to detect a statistically significant effect of duration of tamsulosin use on the risk of intraoperative complications in phacoemulsification surgery.
A Novel Counter Electrode Based on Hierarchical Porous Carbon for Dye-Sensitized Solar Cells
Authors: Wang Gui Qiang , Xing Wei , Zhuo Shu Ping
Published: June 2011

Hierarchical porous carbons (HPC) were synthesized by a combination of self-assembly and chemical activation method. A mesoporous carbon with large-size pore was used as raw materials. N2sorption measurement indicated that plenty of micropores generated within the mesopore wall in the mesoporous carbon during KOH activation. Electrochemical impedance spectroscopy measurement demonstrated a high electrocatalytic activity of HPC electrode for triiodide reduction. The overall conversion efficiency of dye-sensitized solar cells with HPC counter electrode was 6.48%, which is similar to that of the device with conventional Pt counter electrode.
Application of Mikania micrantha as an Additive of High Strength Eco-Materials
Authors: Huang Ying Pin , Chien Chuan Chi , Liou Yan Jia , Huang Wu Jang , Chang Tzu Yi
Published: June 2011

Mikania micrantha has invasive alien species harmful to many plants; it natively grows in South and Central America area. But now it is found throughout Asia and India area. It has a big reproductive capacity, so several researchers ever used thermal treatment, controlled-environmental treatment, mechanical treatment and biological control treatment to inhibit Mikania micrantha growth. However, rare studies use Mikania micrantha to make building materials. In this paper we will attempt to use untreated and treated (treated by carbonization) Mikania micrantha for making building bricks. Results are shown that the optimal uniaxial compressive strength occurred as 30 wt. % of the carbonized Mikania micrantha; the optimal uniaxial compressive strength took place as 40 wt. % of carbonized Mikania micrantha with an addition of organic acid. But the fresh Mikania micrantha has a lower uniaxial compressive strength, so we used interpolation method to calculate the optimized mixing ratio would be 5:95 for the fresh Mikania micrantha. In addition, Mikania micrantha as building material has no biotoxicity for E. coli.
Experimental Research on Ultrafine Coal Powder for Methane Adsorption
Authors: Zhang Zeng Zhi , Zhou Shuang , Wang Bo Tao
Published: June 2011

A new adsorption material technology and its adsorption mechanism were studied in this paper. Anthracite and lignite were taken as raw materials in those experiments. Firstly, the coal was made into different sizes by ball mill then cooked in tube furnace so as to obtain the ultrafine coal material for methane adsorption. Secondly, the ultrafine coal powder which fully adsorbed methane was gone through the gas chromatography analysis to choose the best samples. Finally, the characterization of adsorption and adsorption mechanism were researched by the micro-morphology analysis, thermal analysis, X-ray diffraction analysis, BET surface area-aperture-volume analysis and infrared spectral analysis. The results of experiments showed that the ultrafine lignite powder which mainly consists of microporous, is more suitable for methane adsorption. Under the same treatment condition, the adsorption capacity of lignite series is better than that of anthracite series. After milling for 120 minutes and coking in medium temperature, the lignite could be used as the best material of ultrafine coal powder for methane adsorption.
Investigation of Mikania micrantha Charcoal Applied on Cultural Media
Authors: Huang Ying Pin , Peng Chia Wen , Huang Yi Han , Tsai Ting Ru , Kuo Wei Ru , Lin Hen Chien
Published: June 2011

Mikania mirantha is a pernicious world-class weed with extremely high threats to the native flora, and ranks no. 1 on the invasive alien plants list. In this study, Mikania mirantha was carbonized to form the carbide, which is called Mikania mirantha charcoal (MMC). MMC’s pH value more than 9 increases with the carbonizing temperature. Besides, MMC has many microelements consist of calcium, magnesium, potassium and silicon that are helpful to the growth of the plant. Therefore, this research is to investigate the physical and chemical properties of MMC-mixed peat media and the seedling index of the vegetable for using MMC mixed with peat media to substitute the commercial perlite peat (CPP) as culture media of the vegetable seedlings. The results showed that MMC-mixed peat media (MMC-P) whose total porosity was more than 85% were belonged to the type of lighter media. The pH value of MMC-mixed media before seeding belongs to neutrality and close weak alkali. After seeding for the 39th day, the seedling index of MMC-mixed media was 0.086-0.101, which was a little lower than that of CPP, 0.11. It resulted from a higher pH value from MMC. As a whole, MMC would be also used as the biofertilizer to improve the acid soil. This study suggests that MMC can be washed by other natural acidity media to change its pH value, which is possible to promote MMC-mixed media to substitute CPP media.
The Adsorption Performance Study of Acid Leaching Residue of Asbestos Tailings
Authors: Chen Jun Tao , Han Yue Xin , Ding Shu Fang , Zheng Shui Lin
Published: June 2011

Acid leaching residue of asbestos tailings was calcined at 600°C. N2adsorption and desorption isotherms of this modified mineral material were measured at low temperature and the adsorption characteristic of acid leaching residue as well as the mechanism were discussed. The specific surface area of acid leaching residue was calculated by BET model, and meanwhile micropore and mesopore structural parameters were calculated by means of ‘t-Plot’ and BJH theory, respectively. The results showed that the N2adsorption-desorption isotherms of acid leaching residue were in line withⅠpattern of the IUPAC isotherm criterions. The residue contained well-developed micropore and mesopore system. The adsorption performance of of Pb2+in simulated wastewater for the acid leaching residue was also performed. The results indicated that a predominant chemisorption, which could be fitted by Langmuir isotherm, occurs on the materials.
A Simple Texturization Approach for Mono-Crystalline Silicon Solar Cell with Low TMAH Concentration Solution
Authors: Ou Wei Ying , Zhang Yao , Li Hai Ling , Zhao Lei , Zhou Chun Lan , Diao Hong Wei , Liu Min , Lu Wei Ming , Zhang Jun , Wang Wen Jing
Published: June 2011

Texturing for mono-crystalline silicon solar cell by chemical anisotropic etching is one of the most important techniques in photovoltaic industry. In recent years, tetramethylammonium hydroxide (TMAH) solution or a mixture of TMAH solution with IPA was reported to be used for random pyramids texturization on silicon surface due to its non-volatile, nontoxic, good anisotropic etching characteristics and uncontaminated metal ions. However, most of the studies were reported about the etching processes by using high TMAH concentration solutions. In this study, a simple and cost-effective approach for texturing mono-crystalline silicon wafers in low TMAH concentration solutions was proposed. Etching was performed on (100) silicon wafers using silicon-dissolved tetramethylammonium hydroxide (TMAH) solutions (0.5~1 %) without addition of surfactant. The surface phenomena, surface morphology and surface reflectance have been analyzed. A textured surface with smaller and smooth pyramids can be realized by using 1 % silicon-dissolved TMAH solutions.
Reaction Mechanism between Zn2+ and Diatomite in Preparation of Zn2+/Diatomite Antibacterial Agent
Authors: Liang Ning , Ding Hao , Hu Yong Teng , Wang Bai Kun
Published: June 2011

The reaction mechanism between Zn2+and diatomite in preparation of Zn2+/diatomite antibacterial agent by diatomite adsorbing and solidifying Zn2+in its pores was studied. Microporous adsorption, characterized by hydrated Zn2+adsorbed in the micropores of diatomite, and surface coordinate adsorption, featured with coordination of Zn2+with functional groups on the surfaces of diatomite, were the main adsorption ways accompanied by ion exchange adsorption and physical adsorption. SEM was used to observe the morphologies of diatomite before and after adsorption. Due to the dehydration between OH groups on the surfaces of diatomite when heat treated at high temperature, Si-O-Zn bonds were formed, combining Zn2+with diatomite together. Reaction model between Zn2+and diatomite was established.
Research on the SDS + Castor Oil Aqueous Solution Used as Methane Absorption and Gas Explosion Suppression Material
Authors: Zhang Zeng Zhi , Xu Hong Mei , Gu Na
Published: June 2011

A kind of water-based material which can absorb mine gas and suppress gas explosion was designed for the purpose of keeping the coal mine safe. The anionic surfactant sodium dodecyl sulfate (SDS) was used as the main gas absorbent according to the micelle solubilization of surfactant, and castor oil was used as absorption enhancer in this material. Methane was regarded as a model of mine gas. The volume fraction of methane absorption was measured by head space gas chromatography. The state of the aggregates in the material was observed by transmission electron microscopy. The explosion suppression effect was tested by self-made explosion chamber which can simulate gas explosion. Also the methane absorption rate of the water-based material was tested in practice of coal mine. The results showed that the maximum volume fraction of methane absorption of the SDS + castor oil aqueous solution can reach up to 12.65%; with the addition of castor oil, the structure of aggregates in SDS aqueous solution system changed from spherical to lamellar, so it can provide greater non-polar microenvironment for methane; the water-based material can lower the maximum explosion pressure to some extent when it was sprayed into the explosion chamber in atomization condition before ignition; field test on methane absorption showed that the methane absorption ratio can reach up to 16.7%, which is much higher than the experimental value.
Structural Characteristics of the Fly Ash Wrapped by the Super Absorbent Resin among the Plant Fiber and the Application Research on the Complex
Authors: Zhao Jin , Deng Ping Ye , Chen Shun Cong
Published: June 2011

This paper presents a kind of water-saving material of the fly ash composite growth substrate in order to solve the problem of the lawns high water consumption. The morphology of the growth substrate was observed by scanning electron microscope. The water keeping and releasing characteristics of the growth substrate were analyzed by the fast moisture analysis and thermal analysis, respectively from the macro and micro perspective. Compared with the common cultivated soil planting tests, the differences between the composite growth-substrate planting and the common planting were got under the similar culture environment. The results show that the typical micro-morphology of the growth substrate is the fiber interspersed among the fly ash particles/cluster which is wrapped by the super absorbent resin, and the whole structure has a good performance at water retention and water releasing. The seeds that planted in the growth substrate can germinate and survive basically and the tests preliminary reach the target of the artificial water-saving.
Synthesis and Characterization of a Rosin Gemini Surfactant
Authors: Chen Zhi Jun , Li Shu Jun , Tian Bing , Liang Tao , Jin Yan
Published: June 2011

Rosin is reputed as green petroleum because it is renewable, not expensive, and environmental friendly. China is rich in rosin resources. In the paper, rosin was used as material to prepare a rosin Gemini surfactant, bisquaternary ammonium salt(BQA) of rosinate. The specific method was as follows: firstly, the rosin was modified by acrylic acid and a carboxylic acid group was introduced to the rosin. Secondly, the modified rosin reacted with the epoxy chloropropane, the intermediateⅠwas obtained by the way. Thirdly, the intermediate reacted with dimethylamine in the mole ratio of 1:3, the reaction time of 4.5h at 80°C. By this way the intermediateⅡwas synthesized. Finally the intermediateⅡ reacted with the epoxy chloropropane and distilled water in the mole ratio of 1:3:3, the reaction time of 4.5h at 80°C. Liquid chromatography(LC) analysis proved that the purity of the product was 90.8% and the yield of BQA was 67%. The chemical structure of this rosin derivative as a BQA was also conformed by Fourier Transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance(NMR) analysis. As Gemini surfactant, the surface activities of the product were characterized. Its critical micellar concentration(CMC) was 4.0×10-4mol/l. Its foaming power of the product was 250mm at 0s, 200mm at 5min. The emulsifying power of the product was 56min. Since the product has good surface activities and it is obtained easily from rosin. It has a promising future as a surfactant.
Synthesis of Zeolite 4A from Kaolin and Bauxite by Alkaline Fusion at Low Temperature
Authors: Zhu Yue Lin , Chang Zeng Hua , Pang Juan , Xiong Chang Jian
Published: June 2011

Zeolite 4A was synthesized by fusion method using kaolin and bauxite as raw materials. It comprised alkaline fusion followed by hydrothermal treatment with step-change of synthesis temperature. The synthesized zeolite 4A samples were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and their calcium ion exchange capacity were tested by ethylene diamine tetraacetic acid (EDTA) volumetric method. The influence on the quality of zeolite 4A was investigated under different fusion temperature, fusion time, and mole ratio of SiO2/Al2O3, Na2O/SiO2and H2O/Na2O. The optimum reaction parameters were determined. The results showed that the reasonable fusion temperature and time should be 600°C and 2 h, and the reasonable ratios of raw materials were the SiO2/Al2O3ratios from 1.8 to 2.2, the Na2O/SiO2ratios from 2.0 to 2.3, and the H2O/Na2O ratio at 60, respectively.
Effects of IPA on Texturing Process for Mono-Crystalline Silicon Solar Cell in TMAH Solution
Authors: Ou Wei Ying , Zhang Yao , Li Hai Ling , Zhao Lei , Zhou Chun Lan , Diao Hong Wei , Liu Min , Lu Wei Ming , Zhang Jun , Wang Wen Jing
Published: June 2011

Texturization of mono-crystalline by chemical anisotropic etching is one of the most important technologies for modern silicon photovoltaic. IPA is usually added to the alkaline etchants to improve the uniformity of the random pyramid texture due to remove hydrogen bubbles sticking on the silicon wafer by improving the wettability of wafer surface. In this investigation, we carried out a systematic study on the influence of IPA concentrations on the textured surface. The etching experiments were performed on (100) silicon wafer in a mixture of 20 vol. % commercial TMAH solutions (10 wt.%) and IPA (rang from 0~12 vol. %) for etching time ranging from 10 to 70 min at 80°C. The etching mechanism in the TMAH solutions with IPA addition was explained basing on the experimental results and the theoretical considerations.
The Performance Study of Aviation Fuel Added with Alcohols
Authors: Zhu Yue Lin , Meng Zhe Yi , Chang Zeng Hua , Xiong Chang Jian
Published: June 2011

Alcohols ranging from C2 to C8 are added to RP-3 jet kerosene to alleviate the pollution when fuel burns. Such mixed fuels are tested in respects of density, viscosity, heat value, rubber compatibility, silver corrosion and copper corrosion. The results show that fuel mixed with n-pentanol resembles RP-3 kerosene best and fuels mixed with ethanol, propanol and n-butanol perform inferior than other mixed fuels in the test for compatibility with rubber. All seven fuels perform well for the test in silver corrosion and copper corrosion. The result for the fuel mixed with ethanol lies slightly behind others in copper corrosion.
Biosynthesis of Carboxymethylated Bacterial Cellulose Composite for Wound Dressing
Authors: Yu Jun Wei , Liu Xiao Li , Liu Chang Sheng , Sun Dong Ping
Published: June 2011

A novel bacterial cellulose (BC) composite (carboxymethylated-bacterial cellulose, CM-BC) was synthesized by Acetobacter xylinum by adding water-soluble carboxymethylated cellulose (CMC) in the culture medium. FTIR results showed that CM-BC is obtained by the incorporation of CMC in the network of BC. Water-holding capacity and water vapor transmission rates (WVTR) of CM-BC and BC are determined. The WVTR of CM-BC is comparable to that of BC, but the water-holding capacity of CM-BC is improved compared with BC. Tensile strengths measurement results showed that the fracture stress of CM-BC is higher than that of BC, indicating that CM-BC have more potential wound dressing applications than BC.
Study on the Cytotoxicity In Vitro of Composite Materials Based on Poly(L-Lactide-Co-Glycolide) and Bioactive Glass
Authors: Zhou Zhi Hua , Gao Yong Yi , Yi Qing Feng , Liu Qing Quan , Liu Li Hua
Published: June 2011

The effect of poly(L-lactide-co-glycolide)/bioactive glass (PLGA/BG) on cell attachment, proliferation and differentiation of L929 fibroblastic cells was investigated. The results ofin-vitrocytotoxicity test indicated that the cells cultured in extract of PLGA/BG and on the surface of composite showed normal growth and proliferation. The cell proliferation and alkaline phosphatase (ALP) activity of fibroblast were significantly improved after 3 and 7 days of culture on PLGA/BG films in comparison with PLGA films. It can be concluded that the addition of bioactive glass into PLGA stimulates the proliferation and differentiation of fibroblastic cells. Therefore, PLGA/BG composites have a promising biological response as a potential biomaterial in medical field.
Synthesis, Microstructure and Properties of Poly(L-Lactic Acid-Co-α-Alanine) Obtained by Direct Melting Copolymerization
Authors: Liu Lian , Chen Xie Wei , Wang Pei , Wei Zhi Yong , Liu Chun Yun , Qi Min
Published: June 2011

A new poly(ester amide)s (PEA) derived from L-lactic acid and α-alanine have been synthesized by melting copolymerization with p-toluenesulfonic acid (TSA) with stannous chloride (SnCl2) as catalyst. The products were analyzed by NMR, FT IR techniques. The effects of the content of α-alanine (L-Ala) on the copolymers structure were studied. Being the phosphate buffered saline (pH=7.2) as the degradation solution, the degradation rate speed up with the increasing the content of the α-alanine.
Tetracycline Double Labelling Tracing Investigation for In Vivo Osteogenetic Course of PDLLA/HA Composite
Authors: Wang Xin Yu , Shan Xue Zhi , Han Yin Chao , Li Shi Pu
Published: June 2011

The PDLLA(DL-Poly lactic acids)/HA(Hydroxyapatite) composite and pure PDLLA control were implanted in bone for test. Using fluorescent pictures of tetracycline double label and advanced image analysis system, the trend of bone-formation rate for the implanting region of PDLLA/HA composite was obtained via morphometry measurement of the slices labeled with tetracycline. The investigation and calculation results show that, the formation rate of new bone is stable and high (reaches 2.044μm/day) in the early stage of implantation for the PDLLA/HA composite, demonstrating the advantageous capability of bone formation for the composite. The formation rate of new bone seems to decrease continuously with time, and then the bone formation and bone decomposition tend towards equilibration. Namely, the dynamic balance of bony tissue’s metabolism is maintained.
Enhancing the Performance of Dye-Sensitized Solar Cells by Incorporating Mesoporous Carbon in Polymer Gel Electrolyte
Authors: Wang Gui Qiang , Wang Liang , Zhuo Shu Ping
Published: June 2011

Mesoporous carbon (MC) materials with surface area of 400 m2g-1were prepared and incorporated into the polymer gel electrolyte comprising of polyvinylidene fluoride and 1-methyl-3-hexylimidazolium iodide to fabricate the composite gel electrolytes. The photovoltaic performance of the quasi-solid-state dye-sensitized solar cells was improved through incorporating MC into electrolyte. The dye-sensitized solar cell with composite gel electrolyte containing 3 wt% MC achieved the best photovoltaic performance, and the corresponding open-circuit voltage, short-circuit current density, fill factor and overall conversion efficiency were 0.59V, 13.22 mAcm-2, 0.66 and 5.15%, respectively. The stability of dye-sensitized solar cells with composite gel electrolyte was far superior to the cell with organic liquid electrolyte.
Flow Behavior and Microstructural Evolution of ZW61 Alloy during Hot Compressive Deformation
Authors: Tang Wei Neng , Chen Rongshi , Han En-Hou , Ke Wei
Published: June 2011

The flow behavior and microstructural evolution of the ZW61 (Mg-6Zn-0.6Y-0.5Zr ) alloy during uniaxial compressive deformation at temperatures of 250-400°C and strain rates of 0.5-0.001s-1.were investigated. The results indicated that the flow stress could be described with a power law equation related to the temperature and strain rate. Furthermore, the deformation microstructures at different strain rates and temperatures were different. Microstructural evolution deformed under 350 °C and 0.001s-1 found that the twinning and different modes of slip systems were selectively activated during deformation, and that misorientation in some grains increased with lattice rotation during hot deformation, which resulted in the gradual formation of new grain boundaries. In addition, dynamic recrystallization (DRX) preferably took place nearby the boundaries of original grains/twinning/slipping bands and coarse particles, which resulted in an inhomogeneous deformation microstructure, i.e. necklace microstructure.
Galvanic Corrosion Behavior and Three Protection Techniques of Magnesium Alloy Coupled to A6N01S-T5 Aluminum Alloy in NaCl Solution
Authors: Zhang Ding Fei , Liu Yu Ping , Chen Chang Guo , Xu Ya Juan
Published: June 2011

In this work, the galvanic corrosion behavior of AZ31 magnesium alloy in contact with A6N01S-T5 aluminum alloy in NaCl solution was investigated by electrochemical method, the salt immersion method, SEM. And three protection techniques: (a) rubber gasket technique ,(b)organic coating technique and (c) anodizing technique were used to inhibit the galvanic corrosion. The results of open circuit potential and polarization curve method were explained the corrosion behavior of AZ31 and A6N01S-T5.It was found that AZ31 as anode was accelerated corrosion and A6N01S-T5 as cathode was also corrode in salt immersion experiment. With the increasing of immersion time, the corrosion rate of AZ31 and A6N01S-T5 was gradually decreasing. Then, the efficacy of different anti-corrosive technologies was compared. Fluorine coating technique was an effective way to protect Mg alloy and Al alloy. It was possible to guide the anti-corrosion of magnesium alloy in mobile industry.
High Cycle Fatigue Behavior of Gravity Cast AZ91D Magnesium Alloy
Authors: Yang You , Wu Hua , Li Xue Song
Published: June 2011

High cycle fatigue behavior of gravity cast magnesium alloy AZ91D were investigated using an up-and-down load method. High cycle fatigue tests were carried out up to 107cycles at a stress ratio R=0.1 and frequency of 90Hz on specimens using a high frequency fatigue machine. Fatigue fracture surfaces of specimens that in the high cycle fatigue tests were also observed using a scanning electron microscope for revealing the micro-mechanisms of fatigue crack initiation and propagation. The results showed that fatigue limit of AZ91D alloy at room temperature is 54.5 MPa under the numbers of cycle to failure Nf=107 conditions using up-and-down method calculation. The fatigue strength of the alloy is about 32% of its tensile strength. The micro-fatigue fracture surface of AZ91D alloy included three representative regions. These regions are fatigue initiation area, fatigue crack propagation area and fatigue fracture area. Fatigue cracks of AZ91D alloy initiate principally at inclusions of alloy surface and subsurface, and propagate along the grain boundary. The fatigue striations of fatigue crack propagation area are not clear. The fatigue fracture of test specimens shows the rupture characteristics of quasi-cleavage.