bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation & Characterization of h-BN Coatings on Ti-Based Substrate Synthesized via the PDCs Route: Tribological Applications in Severe Conditions
Authors: Yuan Sheng , Toury Bérangère , Benayoun Stephane
Published: June 2012

H-BN coatings can be achieved by the Polymer Derived Ceramics (PDCs) route on metallic substrate, i.e. titanium. The ceramization process is led via an optical treatment by IR irradiation to overcome the problem of the metal stability at high temperature (needed in classical process). Structural and chemical characterisations by XRD, IR, RAMAN and EDS show that the obtained crackless coatings have a micro composite structure composed by a µ-layer of TiBx/TiN at the interphase, the h-BN coating and a layer of BN(O) at the surface. Hereafter, tribological and mechanical analyses investigated through nano- and micro-indentation give a weak friction coefficient and show a good adherence between the substrate and the coating. This good adherence can be explained by the formation of Ti-B-N bond at the interface.
Fabrication and Properties of AlN/CNT Composite Ceramics
Authors: Liang Hai Long , Li Yong Li , Tang Jie , Liu Hai Lin , Huo Yan Li , Chen Yu Feng
Published: June 2012

High thermal conductivity and dense AlN/CNT composite ceramics with additive Y2O3 were fabricated by spark plasma sintered (SPS) in this paper. The results indicated that CNT blocked the densification process in a certain extent, but in the sintering temperature of 1700°C, the relative density of composite ceramics were more than 97% with 1-10% volume fractions of CNT. The content of additive Y2O3 affected the thermal conductivity of AlN/CNT obviously. The thermal conductivity of composite material linearly decreased when the content of CNT increased and the tubular structure of CNT had been destructed during once sintering. The effects of the CNT structural damage to the thermal conductivity of composite ceramics were improved by adjusting the sintering process. The thermal conductivity of the composite ceramics with 3% volume fractions of CNT sintering in 1550°C/3min×3 was up to 145W/m•K, which higher than the single-phase AlN ceramics.
Fabrication of the SiOC/HfO2 Ceramic Composites by the Sol-Gel Method
Authors: Shou Dai , Ruan Ding Shan , Hou Feng
Published: June 2012

In this paper, Hf element was introduced into the Si-O-C network by the sol-gel method using the dimethyldiethoxysiloxane (DMDES, (CH3)2Si(OC2H5)2) and hafnium tetra(n-butoxide) (HfOR, Hf(OC4H9)4) as raw materials. The SiOC/HfO2 ceramic composite was obtained by pyrolyzing Si-Hf-O-C gel at 1000 °C in argon. FT-IR spectra revealed the presence of Si-O-Hf peaks at 932 cm-1. The weight loss of the as-prepared SiOC/HfO2 was about 0.2 wt.% under argon atmorsphere up to 1550 °C, which was much lower than the hafnia-free SiOC composites and exhibited a remarkable improved thermal stability.
WC-Ni-SiCw Alloys Prepared by Hot-Pressed Sintering
Authors: Ren Xiao Yong , Peng Zhi Jian , Rong Hui Yong , Peng Ying , Fu Zhi Qiang , Wang Cheng Biao , Wen Yue , Qi Long Hao , Miao He Zhuo
Published: June 2012

WC-Ni-SiCw alloys were prepared through hot-pressed sintering by using WC, Ni, VC, TaC and SiC nano-whisker as raw materials. The influence of SiC whisker addition on the microstructure and mechanical properties of the as-prepared WC-Ni alloys was investigated. Except WC hard phase and Ni binder phase, no other phase was detected by X-ray diffraction. The observations by scanning electron microscope demonstrated that there were some micropores in the as-prepared materials, and their size and quantity increased with increasing amount of SiCw. Vickers hardness and flexural strength tests indicated that the bulk hardness of WC-Ni-SiCw alloys slightly decreased with increasing amount of SiCw; and the flexural strength increased at first and then decreased with increasing amount of SiCw. The alloys with 0.53 wt% SiCw presented the highest flexural strength of 1700 MPa.
Evaluating Adhesion of Ceramic Coatings by Scratch Testing
Authors: Li Kun Ming , Bao Yi Wang , Wan De Tian , Huo Yan Li , Wu Jin Yi
Published: June 2012

Adhesion is one of the most important mechanical properties of ceramic coatings. Scratch testing is considered as a simple and effective method to evaluate adhesion of ceramic coatings. In this paper, the critical normal forces and scratch morphologies for different coating-substrate systems were studied by scratch testing. It is shown that the critical normal force obtained by acoustic emission (AE) signals decreases from 12 N to 7 N when the applied normal force rate increases from 20 N/min to 100 N/min for CVD SiC on C, and the failure area of this scratched sample increases with increasing maximum normal force; Based on scratch morphologies, spallation or delamination can be observed for hard-brittle coatings on glass or metal, while discontinuous or continuous ductile perforation can be observed for ductile coatings on metal; The critical normal force for hard-brittle coatings can be effectively obtained by AE signals.
GIAXD and XPS Characterization of sp3C Doped SiC Superhard Nanocomposite Film
Authors: Yi Jian , He Xiao Dong , Sun Yue , Xie Zhi Peng , Xue Wei Jiang , Cao Fen Yan
Published: June 2012

The sp3C doped SiC superhard nanocomposite films had been deposited on stainless steel (SS) substrates at different temperature by electron beam-physical vapor deposition (EB-PVD). The sp3C doped SiC film was studied by grazing incidence X-ray asymmetry diffraction (GIAXD), and X-ray photoelectron spectroscopy (XPS). The results of GIAXD showed that the sp3 doped SiC nanocomposite films were not perfect crystalline, which was composed with fine SiC nanocrystals, and a second phase very similar with diamond like carbon (DLC). XPS analysis showed that the excess C existing in films and turned from diamond into DLC from the surface to inner of film.
Thermal Stability and Structure of Tellurite Glass
Authors: Hou Zhao Xia , Xue Zhao Lu , Wang Shao Hong , Hu Xiao Dan , Lu Hao Ran , Niu Chang Lei , Wang Hao , Wang Cai , Zhou Yin
Published: June 2012

Oxyﬂuoride tellurite glass with the composition of TeO2-AlF3-LaF3-ZnO/ZnCl2/ZnF2 was prepared successfully. The thermal stability and structure of TeO2-AlF3-LaF3 system tellurite glass were studied bySubscript text DSC and IR spectra. The results indicated that glass transition temperature of TeO2-AlF3-LaF3-ZnO/ZnCl2/ZnF2 glass was higher than that of (1-x)TeO2-xAlF3 (x=10%, 20%, 30%, 40%, 50%, in mol%) binary glass system slightly. A small number of ZnF2/ZnCl2/ZnO (5mol%) improved glass thermal stability. After adding 5mol% ZnF2/ZnO/ZnCl2 into fluoride tellurite glass respectively, glass transition temperature increased in turn. The introduction of 5mol% different zinc compounds had a little impact on the glass network structure.
A 3D Cohesive Element Model for Fracture Behavior Analysis of Ceramic Tool Materials Microstructure
Authors: Yu Hai Bin , Huang Chuan Zhen , Liu Han Lian , Zou Bin , Zhu Hong Tao , Wang Jun
Published: June 2012

A 3D finite element polycrystalline microstructure model of ceramic tool materials is presented. Quasi-static crack propagation is modeled using the cohesive finite element method (CFEM) and the microstructure is represented by 3D Voronoi tessellation. The influences of cohesive parameters, the ratios of maximum traction of grain boundary to maximum traction of grain on the crack patterns of Al2O3 have been discussed. This study has demonstrated the capability of modeling 3D crack propagation of ceramic microstructure with CFEM and Voronoi tessellation model. It is found that the fracture mode is changed from intergranular to transgranular as the maximum traction of grain boundary is increased.
Investigations of Transient Machined Workpiece Surface Temperature in High Speed Peripheral Milling Using Inverse Method
Authors: Liu Zhan Qiang , Zhang Fan , Jiang Fu Lin
Published: June 2012

In high speed machining, temperature distribution in workpiece is the main factor which directly affects the surface integrity and dimensional accuracy of machined workpiece. In this paper, the machined workpiece temperature in high speed peripheral milling is analyzed through using moving heat source method and inverse method. Firstly, the workpiece to be machined is considered as a semi-infinite solid to model the transient surface temperature using arc-shaped moving heat source. Inverse method is then applied for the calculating of heat flux. Peripheral milling experiments of 1045 steel is performed with coated carbide insert The machined surface temperatures were measured during experiments. The measured results were found to be in agreement with the predicted ones by transient models for machined surface temperatures. These results confirm the conclusion that the transient workpiece temperature will decline when the cutting speed increases to a critical value.
Predicting Range of Chip Breaking of 3D Complex Groove Turning Inserts with Neural Networks
Authors: Feng Xin Min , Tan Guang Yu
Published: June 2012

BP neural networks model which was used to predict the rang of breaking chip of 3D complex groove turning inserts was established, then training and testing of the network was realized with MATLAB, finally ,range of breaking chip of the insert which was designed by the author was predicted. Percentage of accuracy of predicting results reached 91.67% comparing with the chip breaking experiment. This indicates that neural networks can be used to predict rang of breaking chip of turning inserts, so, saving the inserts which is used for cutting experiments and work of experiments, reducing the periodic time of inserts designing and development, increasing the competitive strength of inserts.
The Experimental Modal Analysis of High Speed Machining Tool System Based on Integral Polynomial Recognition Method
Authors: Xiao Fei , Liu Xian Li , Wang Yan Xin , Liu Li Jia , Qu Da
Published: June 2012

According to the principle of the experimental modal analysis, this study is based on tool system of the MIKRON UCP 710 numerical control machining center as test object for experimental modal analysis. Using the integral polynomial recognition method to identify the modal parameters (natural frequency, structural damping, and modal shape), and finally matching the results with the vector analysis method and the finite element simulation method. The results show that integral polynomial recognition method has higher precision than the vector analysis method to identify the multi-degree of freedom system; the experimental modal analysis can also obtain better modal parameters of the structure system, and a higher precision than the finite element simulation method. Obtained the MIKRON UCP 710 high-speed milling center tool system accurate modal parameters provides the necessary theoretical and experimental basis for the further study of the stability properties in the cutting processing of the high speed machining tool system.
Influence of Tool Flank Wear on Surface Integrity in Orthogonal Milling of Powder Metallurgy Superalloy
Authors: Du Jin , Liu Zhan Qiang
Published: June 2012

Tool flank wear has the significant effects on machined surface integrity. The influences of tool flank wear on the cutting forces, surface roughness, microhardness and white layer thickness are investigated in this paper through orthogonal milling experiments. FGH95 powder metallurgy (PM) superalloys are machined with coated cemented carbide tools in the milling experiments. The experiment results show that with the increasing of tool flank wear, cutting force, surface roughness and white layer thickness increase. However, the machined surfaces micro-hardness aggravates with the increase of tool flank wear. It is found that, the machined surface roughness, micro-hardness and white layer increase dramatically especially when the tool flank wear exceeds 0.3mm. A conclusion is then be drawn that, the maximum acceptable tool flank wear land is 0.3mm from the view point of surface integrity when FGH95 PM superalloy is machined with coated cemented carbide tools.
A Practical Study on the Surface Integrity of High-Speed Cylindrical Grinding of SiC
Authors: Ni Jia Ming , Li Bei Zhi , Pang Jing Zhu
Published: June 2012

In order to reconcile the contradiction between the ceramic grinding efficiency and surface integrity, high-speed grinding with diamond grinding wheel is supposed to be a solution. In this paper, first of all, a normal grinding force model is proposed based on the consideration of the material property and the grinding process parameters. It can be seen that an elevated grinding wheel velocity in combination of a higher workpiece speed can increase the machining rate while maintaining the desired surface integrity. After a series of grinding tests, a comprehensive measurement has been done to study the surface damage by the surface roughness, the microscope profile and the X-ray diffraction. In particular, the effect of the grinding parameters on the ground surface are analyzed and reported.
Experiment on Optimal Selecting for Cutting Tools in Milling of High Hardened Steel
Authors: Zhang Kun Peng , Wang Cheng Yong , Hu Y.N. , Song Y.X.
Published: June 2012

In this paper, with milling characteristics of high hardness hardened steel, we choice six different coated tools to made cutting experiments on high hardness hardened steel Cr12MoV (HRC65). In this stage, through the analysis of cutting force, cutting temperature, cutting vibration, machined quality and tool wear, we have elected the preferred tool and tool geometry parameters for this processing stage. The results of the study show that: TiAlSiN is the most suitable for Cr12MoV (HRC65), which helps to improve cutting processing productivity, prolong tool life, and enhance processing quality and reduce the processing cost.
Drilling of SiCp/Al Composites with Electroplating Diamond Drills
Authors: Zhou Li , Huang Shu Tao , Bai Da Shan , Xu Li Fu
Published: June 2012

SiCp/Al composites have been used in a number of engineering applications including the consumer goods. However, the machining of these materials is very difficult because of the abrasive characteristics of the reinforced particulates. In this paper drilling studies on SiCp/Al composites with high volume fraction and large size SiC particles have been conducted by using electroplating diamond drills, and the influences of the cutting speed on the drilling force and surface roughness were investigated.
The Effect of Cutting Speed on Precision Hard Turning of Hardened Steel
Authors: Chen Tao , Li Su Yan , Jia Dong Kai , Sun Hui , Guo Lei
Published: June 2012

By combining cutting experiment with finite element method (FEM) simulation, the effect of cutting speed on cutting force, cutting temperature and workpiece surface residual stress has been studied in precision hard turning of hardened steel GCr15 with PCBN. The research results indicate that with rise of cutting speed, cutting force somewhat decreases and periodically changes because of metal softening effect, while cutting temperature increases and its maximum lies near tool tip on the interface of cutting chip and cutting edge, and residual stress largely decreases in a small area under workepiece surface and distributes clearly like a spoon. FEM simulation and experimental results are in good agreement.
Actually Geometry of Milling Tool Involved in Cutting Process
Authors: Shi Zhen Yu , Liu Zhan Qiang , Wang Bing
Published: June 2012

The effect of cutting tool geometry has long been an issue in understanding mechanics of cutting process. Tool geometry has significant influence on chip formation, heat generation, tool wear, surface finish and surface integrity during cutting process. This paper presents the actually geometry of milling tool involved in cutting process based on mathematics analytical methods including matrix translation and rotation. Results show that according to the different helix angle and tool fluted, the geometry of cutting tool involved in cutting is different. For two or three-fluted mirco-milling tools, no mater helix angle is 30 or 45, the actually geometry involved in cutting is sphere. Different cutting tool corresponds to different sphere radius. Experiments were set up to validate the effect of cutting tool geometry on cutting forces. Results show that the smaller of the sphere radius of cutting tool, the lower of the cutting force; the larger of the sphere radius, the higher of the cutting force.
Temperature Measurement and Burn Mechanism of Stainless Steel 1Cr11Ni2W2MoV in Grinding
Authors: Zhang Hong Xia , Chen Wu Yi , Fu Xiu Zhuo , Huang Li Xia
Published: June 2012

An experimental study was carried out to investigate the temperature measurement method and burn mechanism in the surface grinding of a stainless steel 1Cr11Ni2W2MoV with SG abrasive wheels. The temperature response at the wheel-workpiece interface was measured using a pair of thermocouple composed of the workpiece material and a single enameled constantan wire which was implanted in the workpiece. Changes in the ground surface morphology and metallography of the specimens in different grinding conditions were analyzed. Plastically deformed coating layers and micro-cracks were observed on ground surface by SEM (Scanning Electronic Microscopy) when grinding burn occurs. Grinding burn mechanism was unveiled from a metallographic point of view. When the average temperature exceeded phase alteration temperature of 1Cr11Ni2W2MoV, the original gray strip martensite structure was replaced by tempered sorbite structure, which caused a sharp reduction of the workpiece surface hardness. The results provided a theoretical and experimental basis for technical optimization in the grinding of high temperature stainless steel with high efficiency and high quality.
Development and Key Technologies of High-Speed Grinding
Authors: Yu Yong , Guo Pei Quan , Cao Yan Ke , Wang Xiao Wei , Zhang Pu
Published: June 2012

The mechanism and characteristic of high speed grinding and the technology and development of high speed grinding were introduced. High efficiency grinding including ultrahigh speed grinding, high efficiency deep grinding, creep deep grinding and abrasive belt grinding was analyzed. The technology about manufacturing the spindle system in super high speed grinding and the other main interrelated technology about grinding were also described.
Combining Magnetism and Ferroelectricity towards Multiferroicity
Authors: Shukla Dinesh , Rajeevan Nhalil E. , Kumar Ravi
Published: June 2012

The attempts to combine both the magnetic and ferroelectric properties in one material started in 1960s predominantly by the group of Smolenskii and Schmid [1. Dzyaloshinskii first presented the theory for multiferroicity in Cr2O3, which was soon experimentally confirmed by Astrov [5,. Further work on multiferroics was done by the group of Smolenskii in St. Petersburg (then Leningrad) [7, but the term multiferroic was first used by H. Schmid in 1994 [. These efforts have resulted in many fundamental observations and opened up an entirely new field of study. Schmid [ defined the multiferroics as single phase materials which simultaneously possess two or more primary ferroic properties. The term multiferroic has been expanded to include materials which exhibit any type of long range magnetic ordering, spontaneous electric polarization, and/or ferroelasticity. In the past decade, several hundreds of papers related to multiferroic materials and magnetoelectric effect have been published every year, making this topic one of the hottest areas in condensed matter physics from fundamental science as well as applications viewpoints. This article sheds light on recent progress about the developments of new multiferroics by combining unconventional magnetism and ferroelectricity with an emphasis on Bi based multiferroic materials. Specifically results of Ti doped BiMn2O5and Bi doped Co2MnO4multiferroics are discussed.
Dielectric Relaxation Phenomena in some Lead and Non-Lead Based Ferroelectric Relaxor Materials: Recent Advances
Authors: Bajpai Parmendra Kumar
Published: June 2012

Relaxors with general formula AA'BB'O3with different cationic distributions at A/B-sites have important device applications in capacitors, piezoelectric ultrasonic transducers, electrostrictive actuators, SAW substrates, etc. The doping or compositional changes in these ceramics can control the high electromechanical characteristics. Lead zirconate titanates (PZT) - based solid solutions exhibit excellent electrochemical properties and are widely used as actuators, transducers, ceramic filters, resonators, sensors and other electronic devices, due to their excellent piezoelectric properties. Although, there has been a concerted effort to develop leadfree piezoelectric ceramics, no effective alternative to PZT has yet been found; most other materials that possess high dielectric and piezoelectric coefficients still contain lead ions. Dielectric relaxation in these materials is of fundamental importance. Recently, new relaxor ferroelectric materials (Pb (B1/3Nb2/3)O3types) have been reported by our group in which the dielectric relaxation character is different from that observed in typical lead based relaxors. In the first part of the review, relaxor characteristics, strategies to synthesize phase pure lead based relaxors and dielectric relaxation phenomena are presented. Deviation of the frequency dependent susceptibility from Curie-Weiss law is analysed both in terms of Gaussian and Lorentzian formalisms. Lead based ferroelectric relaxor materials, due to environmental, health and social reasons are not preferred in devices and attempts are being made to eliminate the lead content from these materials. Sodium bismuth titanate (Na0.5Bi0.5TiO3, abbreviated as NBT), is considered to be one of the excellent candidates for lead-free piezoelectric material. However, pure NBT piezoelectric ceramics are difficult to pole due to its relatively large coercive field and high electrical conductivity. Therefore, many solid solutions of NBT with other ceramics are proposed to improve the relevant properties. In the second part of the review, relaxor behaviour of newly developed solid solutions of NBT is discussed. Finally, the future scope of research on these advance materials is presented.
Intrinsic Free Electrons/Holes at Polarization Discontinuities and their Implications for Basics of Ferroelectricity and its Origin
Authors: Watanabe Yukio
Published: June 2012

This article reviews the theories and experiments on the macroscopic/nanoscopic scales, which indicate that nearly free electrons/holes appear at polarization discontinuities as a result of not only extrinsic mechanisms such as imperfections but also intrinsic mechanisms. We examine the consistency of these theories and experiments with conventional ones. Such electrons/holes lead to various novel properties of ferroelectrics and provide new insight into ferroelectricity, including fundamental issues such as the origin of ferroelectricity. This origin appears naturally compatible with the existence of multiferroicity.
Molecular Spintronics
Authors: Yakhmi Jatinder V. , Bambole Vaishali
Published: June 2012

The emergence of spintronics (spin-based electronics), which exploits electronic charge as well as the spin degree of freedom to store/process data has already seen some of its fundamental results turned into actual devices during the last decade. Information encoded in spins persists even when the device is switched off; it can be manipulated with and without using magnetic fields and can be written using little energy. Eventually, spintronics aims at spin control of electrical properties (I-V characteristics), contrary to the common process of controlling the magnetization (spins) via application of electrical field. In the meantime, another revolution in electronics appears to be unfolding, with the evolution of Molecular Spintronics which aims at manipulating spins and charges in electronic devices containing one or more molecules, because a long spin lifetime is expected from the very small spin-orbit coupling in organic semiconductors. This futuristic area is fascinating because it promises the integration of memory and logic functions,
Endometrial stromal sarcoma: A review of the literature
Authors: Puliyath Geetha , Nair M Krishnan
Published: June 2012

Endometrial stromal sarcomas are rare malignant tumors of the uterus, and most of the information available in literature is based on small series or case reports. A proper preoperative diagnosis is difficult and in most cases the diagnosis is confirmed after hysterectomy for a presumed benign disease. Endometrial sampling, ultrasound, and magnetic resonance imaging can provide diagnostic clues. Total hysterectomy with bilateral salpingo-oopherectomy is the main line of management and for early disease complete cure is a reality. Ovarian conservation may be possible in young women with early stage disease and the role of lymphadenectomy is controversial. Adjuvant hormone therapy in the form of progesterone, gonadotropin releasing hormone analogues, and aromatase inhibitors are found to be effective in preventing recurrences. Hormone therapy, radiotherapy and surgical excision of the metastasis are recommended for recurrences.
Cervical cancer in India and HPV vaccination
Authors: Kaarthigeyan K
Published: June 2012

Cervical cancer, mainly caused by Human Papillomavirus infection, is the leading cancer in Indian women and the second most common cancer in women worldwide. Though there are several methods of prevention of cervical cancer, prevention by vaccination is emerging as the most effective option, with the availability of two vaccines. Several studies have been published examining the vaccine′s efficacy, immunogenicity and safety. Questions and controversy remain regarding mandatory vaccination, need for booster doses and cost-effectiveness, particularly in the Indian context.
Glutamine: A novel approach to chemotherapy-induced toxicity
Authors: Gaurav Kumar , Goel R.K. , Shukla Mridula , Pandey Manoj
Published: June 2012

Treatment of cancer is associated with short- and long-term side-effects. Cancer produces a state of glutamine deficiency, which is further aggravated by toxic effects of chemotherapeutic agents leading to increased tolerance of tumor to chemotherapy as well as reduced tolerance of normal tissues to the side-effects of chemotherapy. This article reviews the possible role of glutamine supplementation in reducing the serious adverse events in patients treated with anticancer drugs. The literature related to the possible role of glutamine in humans with cancer and the supportive evidence from animal studies was reviewed. Searches were made and the literature was retrieved using PUBMED, MEDLINE, COCHRANE LIBRARY, CENAHL and EMBASE, with a greater emphasis on the recent advances and clinical trials. Glutamine supplementation was found to protect against radiation-induced mucositis, anthracycline-induced cardiotoxicity and paclitaxel-related myalgias/arthralgias. Glutamine may prevent neurotoxicity of paclitaxel, cisplatin, oxaplatin bortezomib and lenolidamide, and is beneficial in the reduction of the dose-limiting gastrointestinal toxic effects of irinotecan and 5-FU-induced mucositis and stomatitis. Dietary glutamine reduces the severity of the immunosuppressive effect induced by methotrexate and improves the immune status of rats recovering from chemotherapy. In patients with acute myeloid leukemia requiring parenteral nutrition, glycyl-glutamine supplementation could hasten neutrophil recovery after intensive myelosuppressive chemotherapy. Current data supports the usefulness of glutamine supplementation in reducing complications of chemotherapy; however, paucity of clinical trials weakens the clear interpretation of these findings.
Head and neck squamous cell carcinoma in chronic areca nut chewing Indian women: Case series and review of literature
Authors: Muttagi Sidramesh Shivanand , Chaturvedi Pankaj , Gaikwad Rohith , Singh Bikramjit , Pawar Prashant
Published: June 2012

Background: Head and neck squamous cell carcinoma (HNSCC) is an important public health problem in India. Several risk factors such as tobacco, human papilloma virus, alcohol, areca nut usage have been extensively studied as causative agents. Though Areca nut chewing is known cause of oral cancer, its association with hypopharynx cancer has not been previously reported. Since areca nut is mostly consumed along with tobacco, it is uncommon to find patients who consume the areca nut alone. Materials and Methods: This is a prospective case series of ten women who presented to us with HNSCC with history of chewing of areca nut alone for several years. We have excluded all those cases where areca nut was consumed along with tobacco in any form. The data were prospectively collected with regard to clinical parameters, duration and frequency of areca nut usage, the socio-economic status and education level. Results: All ten females had varying degree of submucous fibrosis and coexisting squamous cell carcinoma either in the oral cavity or hypopharynx. Submucous fibrosis was characterized by burning mouth, unhealthy oral mucosa, buried third molars, trismus, poor oral hygiene, etc. The disease presented in an advanced stage in majority of the cases. All patients were unaware of areca nut′s deleterious effects. Conclusion: Areca nut chewing is an important risk factor for HNSCC in females. Despite plethora of information, little importance is given to areca nut control in cancer prevention campaigns in India.
Gemcitabine and cisplatin-based combination chemotherapy in advanced hepatocellular carcinoma: An Indian experience
Authors: Pande Shripad B , Doval D C , Pavithran K , Sharma J B , Shirali Rashmi , Jena A
Published: June 2012

Background: Gemcitabine, an anti-metabolite, has some activity in hepatocellular carcinoma (HCC) in terms of responses and median survival. Aims: To analyze our experience with the use of gemcitabine in combination with cisplatin in HCC with respect to response, toxicity and survival. Materials and Methods: We studied the records of patients of HCC treated from January 2000 to December 2005 with gemcitabine and cisplatin, and found 24 of them to be evaluable for response, toxicity and survival. Results: Of 24 patients receiving three or more cycles of chemotherapy, six (25%) had a partial response and an additional 12 (50%) had stable disease. The median overall survival (OS) was 7.5 months (95% confidence interval, 4.5-10.5 months) and 1-year survival was 18%. Grade 3 and 4 anemia, thrombocytopenia and neutropenia were observed in, respectively, 17, 17 and 33% patients. The most frequent non-hematologic toxicities were nausea and vomiting and peripheral neuropathy. Conclusion: We report a partial response rate of 25% with stable disease in an additional 50% to three or more cycles of chemotherapy with gemcitabine and cisplatin, with a median OS of 7.5 months (95% confidence interval, 4.5-10.5) and acceptable toxicity profile from our single-center retrospective study of 24 patients of HCC. We trust that, in HCC, gemcitabine is a good drug to be the foundation to build the chemotherapeutic or targeted agents′ combinations on.
Uncommon cause of recurrent infections
Authors: Deotare Uday R , Patel Pranav D , Parikh Rohan P , Bhagat Eva A
Published: June 2012

We descibe the case of a girl of Indian origin who presented with recurrent infections. The only abnormality detected in the armoury of the immune system was consistent neutropenia. Mutation analysis revealed ELA2 (neutrophil elastase) gene mutation that has been associated with severe congenital neutropenia phenotype. Patient was treated with the granulocyte-colony stimulating factor (G-CSF) as prevention of infectious manifestations along with appropriate measure to curb secondary complications. She showed poor response to the G-CSF during stringent surveillance. After being on treatment for 1 year, she developed acute myelogenous leukemia as inherit complication of this disease.
Generalised Jantzen filtration of Lie superalgebras I
Authors: Su Yucai , Zhang Ruibin
Published: June 2012

A Jantzen type filtration for generalised Verma modules of Lie superalgebras is introduced. In the case of type I Lie superalgebras, it is shown that the generalised Jantzen filtration for any Kac module is the unique Loewy filtration, and the decomposition numbers of the layers of the filtration are determined by the coefficients of inverse Kazhdan–Lusztig polynomials. Furthermore, the length of the Jantzen filtration for any Kac module is determined explicitly in terms of the degree of atypicality of the highest weight. These results are applied to obtain a detailed description of the submodule lattices of Kac modules.
The Influence of Time Management Practices on Job Stress Level among Beginning Secondary Agriculture Teachers
Authors: Lambert Misty D. , Torres Robert M. , Tummons John D.
Published: June 2012

Monitoring the stress of teachers continues to be important – particularly stress levels of beginning agriculture teachers. The study sought to describe the relationship between beginning teachers’ perceived ability to manage their time and their level of stress. The Time Management Practices Inventory and the Job Stress Survey were used to measure and collect the data. The study was comprised of 36 beginning secondary agriculture teachers in Missouri. A highlight of the findings suggests that beginning teachers tend to perceive themselves as good managers of time when compared to norm data. Additionally, on average, these teachers are not in a state of stress. Low to negligible relationships exist between the seven time management practices and teachers’ scores on the job stress, job pressure, and lack of support indices.
A Delphi Approach to the Preparation of Early– Career Agricultural Educators in the Curriculum Area of Agricultural Mechanics: Fully Qualified and Highly Motivated or Status Quo?
Authors: Saucier P. Ryan , McKim Billy R. , Tummons John D.
Published: June 2012

According to the National Research Agenda for Agricultural Education and Communication, preservice agriculture teacher education programs should “prepare and provide an abundance of fully qualified and highly motivated agricultural educators at all levels” (Osborne, 2007, 8). The lack of preparation of entry career agricultural educators is no more apparent than in the curriculum area of agricultural mechanics. Saucier and McKim (2010) stated that all school–based agriculture educators who instruct agricultural mechanics must be technically competent and be able to safely manage the school laboratory for effective student instruction. The model for teacher preparation in agricultural education (Whittington, 2005) served as the conceptual framework. The study sought to determine the essential agricultural mechanics skill areas that Missouri agriculture educators must possess prior to beginning a career in agricultural education. Results of this study identified essential agricultural mechanics skill areas that range from laboratory management to soldering. Teacher educators and state supervisory staff should review these skill areas and plan professional development education for current Missouri agricultural educators who have in–service needs in these skill areas. In conclusion, preservice programs in Missouri should be evaluated to determine if they are indeed effectively preparing teachers in the curriculum area of agricultural mechanics.
Assessing the Teacher Self–Efficacy of Agriculture Instructors and Their Early Career Employment Status: A Comparison of Certification Types
Authors: Robinson J. Shane , Edwards M. Craig
Published: June 2012

The purpose of this descriptive–correlational study was to assess the level of teacher self–efficacy of first–year, secondary agricultural education teachers in Oklahoma at the beginning and end of their entry–year in the profession and describe their early career retention. This study found that these first– year teachers increased their level of teacher self–efficacy throughout the year. The alternatively certified (AC) teachers indicated the largest amount of perceived growth across three teacher self– efficacy constructs. However, when considering the assessment scores of university supervisors, it was found that traditionally certified (TC) teachers outperformed their AC counterparts by roughly a one–half point margin on each construct. Further, statistically, the TC teachers performed significantly better on the student achievement indicators standard than did the AC teachers. It was found that the difference in effect size between TC and AC teachers was between “medium” and “large” for all constructs. Finally, this study revealed that, statistically, the TC teachers had significantly higher retention rates as compared to their AC teacher counterparts.
Creative Engineering Through AWWA
Authors: Borello Amy
Published: June 2012

Every engineer has a Lego, or Erector Set, or Lincoln Logs memory. It's that moment when a child realizes he or she loves creating and figuring out how things work ‐ and, possibly, thinking of ways they could be designed better. Cultivating engineering at an early age is crucial.
The smart way to integrate business, systems, and technologies: Driving business and IT alignment
Authors: Spiers Doug , Van Buskirk Rod , Booth Ron , McKinney Scott
Published: June 2012

Improved efficiency and effectiveness can be achieved through the smart use of integrated business solutions that engage strategy, people, process, and technology.
Developing a Security Culture
Authors: Spence Shannon , Shadden Marie
Published: June 2012

Physical security such as fences, access control, and closed‐circuit television are critical to the protection of assets, organizational resiliency, and public safety; and utility managers have made great progress in enhancing physical security at their facilities. However, in the past few years the idea of creating not just secure utilities but resilient utilities has become a key focus of the water sector.
Spectroscopic, thermal and antimicrobial properties of the copper(II) complex of Schiff base derived from 2‐(salicylidene) aminopyridine
Authors: Tantaru Gladiola , Popescu Maria‐Cristina , Bild Veronica , Poiata Antonia , Lisa Gabriela , Vasile Cornelia
Published: June 2012

Schiff bases and their complex combinations with metallic ions represent a class of compounds with antimicrobial activity. A ligand was prepared by condensation of the salicylaldehyde with 2‐aminopyridine obtaining 2‐(salicylidene) aminopyridine (SB) with a high capacity for complexing Cu(II) ions. The new compound has been characterized by physical constants (melting point, solubility, stability) and the chemical structure was confirmed by elemental, spectral (IR, UV–visible, 1H NMR and 13C‐NMR) and thermal analyses. The elemental analysis gives a coordination ratio of 1:2 metal:Schiff base. Lethal dose 50 (DL50) values of new Schiff base and their complex with metallic ions were established. The antimicrobial activity of this complex was tested in comparison with the activity of the corresponding Schiff base on strains of Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Escherichia coli, Candida albicans, and Klebsiella. These were compared with the activity of the reference drugs (chloramphenicol, tetracycline, ofloxacin and nystatin) on the above‐mentioned strains. It has been established that all compounds tested were very active against both Gram‐positive and Gram‐negative bacteria. Copyright © 2012 John Wiley & Sons, Ltd.
Synthetic and natural silica‐aluminates as inorganic acidic catalysts in ring opening polymerization of cyclosiloxanes
Authors: Vallejo‐Montesinos Javier , Villegas Antonio , Jacobo‐Azuara Araceli , Martínez J. Merced , Ramírez‐Oliva Eulalia , Romero‐Izquierdo Araceli , Cervantes Jorge
Published: June 2012

Ring opening polymerization (ROP) of hexamethylcyclotrisiloxane (D3) and octamethylcyclotetrasiloxane (D4) was promoted by acid‐treated synthetic and natural silica‐aluminates. Silica‐alumina (1:3 Si/Al molar ratio) was obtained using a simple and economic route from precipitation of aluminum sulfate solutions. The material was treated in an acidic medium to improve the content of acid sites and successfully tested as inorganic acidic catalyst for ROP of D3 or D4 cyclosiloxanes. Natural bentonite was treated and used in a similar manner. Once the ROP reaction completed, the catalyst was easily removed and it was found that the recovered synthetic silica‐alumina was active in a second ROP reaction. The effect of the concentration and type of catalyst in respect to the molecular weight and polydispersity of polydimethylsiloxanes was analyzed: increasing the amount of silica‐alumina in ROP of D4 from 0.05 to 0.1 g decreased the average molecular weight (Mn = 13–1.8 kDa) associated with an increase in the polydispersity (2.95 vs. 1.81). Analogous results were found with bentonite. These values suggest that an increase in the catalyst concentration led to a lower Mn, with a more homogeneous molecular chain dimension. Copyright © 2012 John Wiley & Sons, Ltd.
Phase behaviors of diblock copolymer/nanorod composites under oscillatory shear flow
Authors: He Linli , Li Shiben , Zhang Linxi
Published: June 2012

The phase behaviors of lamellar diblock copolymers (DBCPs) melts and lamellar DBCPs/nanorods (NRs) composites subjected to oscillatory shear flow, have been investigated using dissipative particle dynamics. The oscillatory shear is a quite common shearing mode used in experiments and manufacturing processes. The rich lamellar (LAM) reorientation and morphological transition of systems strongly depend on the shear amplitude and shear frequency. At very low frequency, the amplitude‐induced phase behaviors of DBCPs melts or DBCPs/NRs composites are quite similar to those subjected to a steady shear. For DBCPs/NRs case, we control NRs concentration low 15% to preserve LAM morphology in the nanocomposites, and simultaneously consider both types of selective and nonselective NRs. Our aim is to compare the different inductions on DBCPs melts or nanocomposites caused by shear amplitude and frequency, and observe how the NRs are oriented and dispersed in phase‐separated copolymers matrix while under oscillatory shear, and how the presence of selective/nonselective NRs affects the shear‐induced LAM reorientations and rheological properties of systems. Our results show the NRs orientation not only directly depend on the imposed shear flow but also is interfered by the alignment of shear‐stretched copolymer molecules. The shear viscosity decreases with the frequency decreases, also influenced by the NRs concentration and surface property. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Synthesis of sulfonated polynaphthalene, polyanthracene, and polypyrene as strong solid acids via oxidative coupling polymerization
Authors: Tanemura Kiyoshi , Suzuki Tsuneo , Horaguchi Takaaki
Published: June 2012

Oxidative coupling polymerization of naphthalene, anthracene, and pyrene with FeCl3 in nitrobenzene under nitrogen gave polynaphthalene (PNP), polyanthracene (PAT), and polypyrene (PPR) in good yields, respectively. PNP, PAT, and PPR were transformed into sulfonated PNP (S‐PNP), S‐PAT, and S‐PPR by the treatment with chlorosulfonic acid in dichloromethane at 25°C for 24 h under nitrogen, respectively. The activities of S‐PPR were higher than those of S‐PNP and S‐PAT. For the hydrolysis of cyclohexyl acetate and oleyl acetate in water, activities of S‐PPR, S‐PAT, and S‐PNP were considerably higher than those of the other conventional solid acids. Rate constants of S‐PPR were 2.8 and 11.7 times larger than those of the sulfonated condensed polynuclear aromatic (S‐COPNA(PR)) resin (PR = pyrene) for the hydrolysis of cyclohexyl acetate and oleyl acetate, respectively. S‐PPR, S‐PAT, and S‐PNP were reused without significant loss of activities. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Upgrading the adhesion properties of a fast‐curing epoxy using hydrophilic/hydrophobic hyperbranched poly(amidoamine)s
Authors: Essawy Hisham A. , Mohamed Heba A. , Elsayed Nadia H.
Published: June 2012

A homologous series of hyperbranched polymers (HBPs) was prepared following a well‐defined method and their formation in a polymeric form bearing different extents of branching with amine functional groups at the terminals was verified using different techniques such as Fourier Transform Infrared, 1H Nuclear Magnetic Resonance, Differential Scanning Calorimetry, and Gel Permeation Chromatography. Toughening of a commercially available fast cure epoxy was aimed through reactive blending with the formed HBPs that exhibit variation in polarity and branching according to the relevant synthesis strategy employed for each polymer. The mechanical properties (impact resistance, pull‐off adhesion, and bending) of the resulting coating films pertaining to each epoxy formulation after adhering to metal substrates revealed obvious progress in their performance with respect to a control sample that was hardened exclusively in absence of any HBP. The results were explained on the light of the ability of this class of materials to impose flexibility and dilute the intensive crosslink density associated frequently with the rapid curing of epoxy systems. The extent of gained enhancement for each formulation was accounted for by the molecular architecture of the HBPs, their degrees of branching, polarity, and relative reactive contents of primary amino groups in each case. In addition, the influence of these parameters on a proper wetting over the substrate and morphology of the films in each case was also studied using scanning electron microscopy. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Modified poly(vinylidene fluoride) hollow fiber composite membranes reinforced by hydroxyapatite nanocrystal whiskers
Authors: Lang Wan‐Zhong , Ji Qin , Shen Jian‐Ping , Guo Ya‐Jun , Chu Lian‐Feng
Published: June 2012

The modified poly(vinylidene fluoride) (PVDF) hollow fiber composite membranes reinforced by hydroxyapatite (HAP) nanocrystal whiskers were fabricated with wet‐spinning method. The PVDF/HAP/N‐methyl‐2‐pyrrolidone dope solutions experienced delayed demixing mechanism, and the precipitation rate slightly increased as the HAP whisker content increased. The cross sections of PVDF‐HAP and neat PVDF hollow fiber composite membranes were composed of five distinct layers: two skin layers, two finger‐like sublayers, and a sponge‐like layer. The Young's modulus of and tensile strength of the PVDF‐HAP hollow fiber membranes gradually increased with the addition of nano‐HAP whiskers. The elongation ratio was also improved, which was different from the polymeric membranes modified by other inorganic nanofillers. The permeation flux of the PVDF‐HAP hollow fiber membranes slightly increased with the increase of HAP content in the composite membranes as its hydrophilicity was improved. The crystallization behaviors of PVDF in the composite membranes were also investigated. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013