bluuebunny/crossref_metadata_2025 huggingface dataset:
A Review on Optimization of Friction and Wear Parameters (Al Alloy-B4C) Composite Using Taguchi Technique
Authors: Prasad Vishwanath , Soni V.K. , rana Ravindra singh
Published: November 2015

Metal matrix composites (MMCs) have proved their viability as good alternatives to conventional alloys in high strength and stiffness application in industries like automobile, aerospace and mineral processing. Al metal matrix composites (MMCs) are being considered as a group of advanced materials for their lightweight, low coefficient of thermal expansion, and good wear resistance properties. The optimization of parameter has been done by using different techniques like Taguchi, DOE and their results were verified by ANOVA. Signal-to-noise ratio and Analysis of variance (ANOVA) were used to investigate the influence of parameters on the wear rate. Based on various papers the conclusion of this review paper is to study the influence of applied load, sliding speed and sliding distance on the various parameter such as optimum wear and co-efficient of friction of Al alloy-B4C composite to enhance the quality of product and suggest the best combination of wear parameter which helps to reduce the wear of product with the help of Taguchi method. The wear resistance of the composite was found to be considerably higher than that of the matrix alloy and increased with increasing particle content. The major observation based on reviewed papers is that the major factor in determining the wear rate is load applied followed by distance and sliding velocity whereas distance affects the coefficient of friction to a large extent followed by load and sliding velocity.
Evaluation of Mechanical Properties of Acacia-Jute-Sisal-Glassfibrereinforced Composite
Authors: Elanchezhian C. , Vijaya Ramnath B. , Ramanan V. , Saisundararam R. , Siddarth C.S.
Published: November 2015

Now-a-days traditional materials are replacing the natural fibres in automobile components like dashboards, seat-backs and interior trims due to its properties like light weight, environment friendly, good stiffness and high strength to weight ratio . In the study three different continuous fibres, Acacia, Jute and Sisal were mixed in varying proportion with GFRP and epoxy resin on a determined ratio basis to get three different composite samples. These fibres were alkaline treated and moulded using compression moulding and hand lay-up technique. These samples were tested for their Tensile and Impact strengths to find the specimen with higher strength. Scanning Electron Microscope (SEM) test was also conducted to study the structure of all three specimens after tensile test. The study concludes that the sample ‘A’ which has maximum content of sisal has higher tensile strength than other two samples. Similarly impact test concludes that specimen ‘B’ and ‘C’ which has maximum content of Jute and Acacia has equal and higher strength.
Experimental Investigations of Material Behaviour in Forward Micro Extrusion
Authors: Rajenthirakumar D. , Sridhar R. , Abenethiri R. , Bagri Dwarkesh
Published: November 2015

Micro manufacturing has received good attention globally in terms of its manufacturing methods and processes. One of the most popular micro manufacturing processes is micro forming. Although there were efforts made to realize micro extrusion for industrial application, the technology itself was seen as being insufficiently mature and unlike conventional methods, there is no in-depth knowledge. It has become essential to develop a proper understanding which in turn could be used to develop dedicated processes for the manufacturing of metallic micro components. In this work, an attempt has been made to realize this special application of metal forming. A novel experimental setup consisting of forward extrusion assembly and a loading set-up has been developed to obtain the force-displacement response. The effects of minaturization on micro components and the material behavior during forward extrusion are investigated. As per industrial requirement and application of micro part in micro manufacturing process, grain size is an important factor. In this context the effect of grain size is also studied in this work. The realization of such a productive forward extrusion assembly poses significant advantages when compared to the conventional manufacturing technologies in the production of micro parts.
Neural Network Based Breakout Prediction System in Continuous Casting Shop
Authors: Ansari Md Obaidullah , Samantray Rajashree , Ghose Joyjeet
Published: November 2015

— Continuous casting of steel is a process in which liquid steel is continuously solidified into semi-finished or finished product (slabs, blooms or billets). There are many problems associated with continuous casting shop which affect the casting process. A major problem is associated in continuous casting shop is breakout of molten steel. Breakout leads to temporary shutdown of caster, damage of machinery due to splash of molten steel, capital loss, safety hazards etc. In Bokaro steel plant a logical based breakout prediction system is used to predict the breakout. This system sometimes generates false alarm and sometimes even fail to generate an alarm before breakout. Also the logical model has lot of dependence on specific equipment, process and calibration. Neural network can be implemented for a better breakout prediction system. So, in this paper a back-propagation neural network model is developed for predicting the existence of primary cracks that might lead to a breakout. The network gets its input temperatures from thermocouples which are attached to the wide and narrow sides of the mould. The output of the neural network is either logic 1 (for presence of crack) or logic 0 (for no crack). Testing the network shows excellent result as evident from the confusion matrix and performance plot. The neural network model is validated by simulating in MatLab/Simulink. The developed network may be used effectively in predicting breakouts during continuous casting. Such effective prediction can go a long way in reducing production losses in steel manufacturing.
Room Temperature Consolidation of Al and B4C Composite Powder by Equal Channel Angular Pressing
Authors: Saravanan Karunanaithi , Senthil Kumar Mariappan , Venkatachalam Perumal , Raghavan Rajaram
Published: November 2015

The aim at the present work is to study the consolidation behavior of Al and B4Ccomposite powder processed by Equal Channel Angular Pressing (ECAP) at room temperature. The composition of the composite powder is 95 wt% Al and 5 wt% B4C. The Al-B4C composite powder is subjected to ECAP through processing route A up to 4 passes. The ECAP die used for densification has 90° channel angle and 20° corner angle. It is found that the density and hardness of the composite are improved as the ECAP passes is increased. The microstructure is homogeneous and partial fragmentation of reinforcement is observed. Density and hardness measured after four ECAP are 97% and 98 HV. The improvement of density and hardness is the due strain enhances consolidation of powders during ECAP.
Effects of Heat Transfer, Magnetic Field and Space Porosity on Peristaltic Flow of a Newtonian Fluid in a Tapered Channel
Authors: Kothandapani M. , Prakash Jayavel , Pushparaj V.
Published: November 2015

In this paper, the influences of magnetic field and porous space of peristaltic flow of a Newtonian fluid in the tapered channel are studied. Flow analysis is also discussed in the presence of heat transfer. A model of wall-induced fluid flow within an infinite tapered channel having symmetric wall displacements and phase difference is developed. Expressions of dimensionless stream function and temperature are obtained analytically by employing long wavelength and low Reynolds number assumptions. The effects of various emerging parameters on the flow characteristics are shown and discussed with the help of graphs. It has been found that The geometric parameters likes, non-uniform parameter, amplitudes and phase difference control the fluid transport phenomena.
Numerical Investigation on Visualizations of Confined Air Flow in a Slot Jet Inside a Rectangular Channel
Authors: Muthukannan M. , Rajesh Kanna P. , Jeyakumar S. , Raja Shangaravel J.Y. , Raghu S. , Rajesh K.
Published: November 2015

In the present numerical investigation, the flow field of confined slot air jet in a rectangular computational domain is reported. In the present work the flow field parameters like reattachment length, vortex center and horizontal velocity profiles for various Reynolds numbers and for various aspect ratios are presented .The present study reveals that the vortex centers are moving in a downstream direction with increase in Reynolds number. The reattachment length is directly dependent on the Reynolds numbers. In case of vortex dynamics, the vortex size is indirectly dependent on the inlet jet width. In the present investigation, SIMPLE algorithm is used to solve the governing equations. It is concluded that the aspect ratio and the Reynolds number are playing dominant roles in flow field of the present computational domain.
Numerical Modeling of Solar Radiation Heat Transfer for a Truck Cabin
Authors: Senthilkumar S. , Ramkumar K. , Velshankar M. , Karthikeyan S. , Parthipan D.
Published: November 2015

The temperature inside the vehicle cabin will be higher than the outside environment temperature in parked conditions due to radiative effects. This increased temperature is not uniformly spread within the driver cabin due to absorption capacities of the various materials used for construction and the angle of incidence of the incoming radiation. The objective of the work is to predict the accumulation of heat inside the cabin numerically and find hotspots throughout the cabin. The path of the sun in different seasons and timings on a particular location was calculated and is implemented for the angle of incidence of radiation on the cabin. The investigation provides the variations of temperature, transmitted solar radiation and amount of absorption by various components that are subjected to assessment. Thus the major contributing factor for the abrupt increase in temperature was found.
Preheating Metal Scrap in Foundries Using Solar Thermal Energy
Authors: Selvaraj J. , Jawahar Chandra C. , Bhatija Khushal A. , Thenagan Saalai
Published: November 2015

The present scenario of energy conservation has witnessed many innovative and eco-friendly techniques and one such area where there is a necessity to conserve energy is foundries. Foundries also pollute the atmosphere with greenhouse gases contributing to 296143037.6 metric tons annually. The proposed technique in this paper aims at reducing the energy utilized in melting the scrap material at foundries by solar thermal energy. In the methodology proposed, solar energy is concentrated onto the scrap placed on a receiving platform using a parabolic trough and heats it up so that the heated scrap takes lesser energy to melt. The experiments resulted in preheating temperature of 100 °C when placed on a receiving platform and 110°C when copper shots are used to conduct heat from receiver to the scrap. This translates to energy conservation of 6%. This eco-friendly technique when adopted can result in substantial savings in consumption and environmental protection.
Thermal Conductivity of Fabrics
Authors: Abitha M. , Roshanara  , Subramaniam V.
Published: November 2015

An Investigation on thermal conductivity of woven fabrics is reported. Thermal conductivity knitted fabrics to be found to be lower that of woven fabrics. Finishes also had an effect on Thermal conductivity.
Thermo Mechanical Modeling of Selective Inhibition Sintered Thermoplastic Parts
Authors: Arunkumar P. , Balasubramanian Esakki , Chandrasekhar U.
Published: November 2015

Contemporary product design and development efforts of various engineering organizations have experienced the emergence of Additive Manufacturing (AM) or 3D printing technology as a competent fabrication option for converting digital data into physical parts without using part-specific tools or fixtures. This paper presents the results of coupled field structural thermal analysis carried out on an innovative variant of AM technology called selective inhibition sintering wherein near net shape parts are fabricated through sintering of thin layers of powdered material while inhibiting the boundaries. Thermal gradients that are inherent to the process cause significant residual stresses affecting the part stability. Hence this study evaluates the effect of layer thickness and heater spot size on temperature gradient, displacement and thermal stress of two different polymers is assessed by numerical analysis. Results of the current study are relevant to enhancing the quality of sintered polymer parts with reference to dimensional fidelity and stability.
Effect of Mahua Biodiesel Blends on the Combustion Characteristics of Direct Injection CI Engine at Various Compression Ratios
Authors: Vagesh Shangar Ramani , Hariram Venkatesan
Published: November 2015

In the current study, combustion characteristics were evaluated using mahua biodiesel blends at different compression ratios on a direct injection CI engine. Non edible mahua oil was transesterified into biodiesel by two stage technique. Combustion parameters were evaluated for B5, B10 and B20 blends of mahua biodiesel with diesel and they were compared with straight diesel at compression ratios of 16, 17 and 18.Compression ratio was varied without altering the combustion chamber geometry and the static spill timing was set to 23° bTDC. Parameters like In cylinder pressure, heat release rate, rate of pressure rise and cumulative heat release were evaluated in this study at 100% engine loading conditions. Higher peak cylinder pressure and heat release was observed at higher compression ratios. The ignition delay of the blends were slightly higher compared to diesel at all CR tested. Peak cylinder pressure of the blends was slightly higher at CR 18. The ignition delay was also observed to be lower at higher compression ratio. The peak pressure was observed closer to TDC at higher compression ratios for all fuels tested.
Experimental Study on Mahua Bio-Diesel – An Alternative Source of Green Energy
Authors: Rajan A.John , Navas Kaja Bantha , Chaitanya Sindiri , Topno Udit R.
Published: November 2015

In the present era there is a great need of green energy. Domestic and industrial requirements depend on the conventional energy sources which are depleting and polluting atmosphere. Many sources of green energy are under research to meet the required demand. In the present experimental work, performance of Mahua bio-diesel is studied and its pollution level is checked by emission test. The test results are compared with that of pure diesel.
Performance and Emissions Analysis of a Diesel Engine Using Various Bio-Fuels
Authors: Kiran Theja Akkaraju H. , Subbarao Rayapati , Phani Rajanish Chava Y.P.D.
Published: November 2015

Rapid depletion of conventional fuels and growing requirements has led the researchers towards alternative sources like bio-fuels. Present work discusses the suitability of those bio-fuels in a naturally aspirated diesel engine by comparing the performance. Initially, the effect of bio-fuels on fuel consumption and thermal efficiencies are studied and compared with diesel. Thermal efficiency is improved and specific fuel consumption reduced, particularly with karanja oil when compared to diesel. Secondly, the energy balance of the engine is compared. Heat losses are found reducing in bio-fuels due to viscosity and heat rejected to coolant is found less with karanja oil when compared to diesel. Also, the engine emissions, particularly oxides of carbon, nitric oxides, and unburned hydrocarbons from bio-fuels and diesel are sensed using five-gas analyzer and compared. NOx and CO2 emissions are slightly more in bio-fuels when compared to diesel, while CO and HC emissions are less for bio-fuels.
Static and Dynamic Analysis of Motor Cycle Wheel Designs
Authors: Eswara Kumar A. , Naga Raju M. , Karteek Navuri , Prakash Daggupati
Published: November 2015

The wheel of a vehicle plays a vital role to bear the load applies on it. Generally spokes acts as the supports between the wheel rim and hub. These spokes must have sufficient strength and stiffness to avoid the failure of the wheel. In present days these wheels are made up of aluminum alloy, magnesium alloy and steel. To reduce the weight of the wheel many wheel designs are implemented and applied for different vehicles. In this paper three different wheel designs are chosen, those are inclined spokes, curved spokes and Y shaped spokes made up of Al alloy, Mg alloy and Steel. Static structural analysis subjected to pressure on the wheel rim and free vibrational analyses are performed by using finite element analysis tool Ansys 12. The objective of the present work is to observe the best design which contains higher structural stiffness, specific structural stiffness with lower von mises stresses under static load conditions. It is observed that curve shaped spoke designs are better in for manufacturing of wheel in both static and dynamic point of view.
Brake Characteristics and Cooling Methods – A Review
Authors: Ramachandran G. , Kathiresan K. , Venkatesan M.
Published: November 2015

Braking system is important in any automobile. It is essential to decelerate the vehicle and stop it. Friction braking system is widely used system of braking. It makes use of frictional force to safely retard the vehicle. The temperature of the brake pad (stator) and disc (rotor) increases because of frictional force between them. Higher temperatures may lead to fading of brakes resulting in its failure. This paper briefly reviews published works on studying the wear and thermal characteristics of brake pads and on various available brake cooling methods. The microstructural changes in the brake pads are analyzed and reason for enhanced wear at higher temperatures is traced out. The various test results obtained using microscope (SEM), Friction assessment screening tests (FAST), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) are described in brief. A description of the available methods of enhancing the brake cooling and decreasing the wear rate is discussed. This work will be useful in planning further research in this important area of automotive field.
Comparative Analysis of Chosen Tolerance Stackup Methods and Development of an Improved Tolerance Analysis Method
Authors: Panneer R. , Jackson A.M.
Published: November 2015

The perception of Tolerance Analysis (TA)/Tolerance Stackup is imperative for every Design and Manufacturing Engineer because Tolerance is the criterion that should be compromised between the cost and function of a product. The literatures relevant to 15 methods of TA which are being used to determine Assembly Tolerance from Component Tolerances are collected and critically analyzed to gain an insight into the existing methods. Out of these methods, four major methods viz., Simulation Based Stack-Up Analysis, Second Order Tolerance Analysis, OpTol - Spatial Tolerance Analysis and Tolerance Analysis of 2D and 3D Assemblies are chosen for further study and comparative analysis. Based on the analysis and based on the identified merits and demerits of these methods, a framework for a new TA Method is developed. Based on the developed framework, a new TA Method using Artificial Neural Network (ANN) is developed and trained which can predict the value of Assembly Tolerance for the known Component Tolerances.
Determination of Constant Orientation Workspace of a Stewart Platform by Geometrical Method
Authors: Gokul Narasimhan S. , Shrivatsan R. , Venkatasubramanian K. , Dash Anjan Kumar
Published: November 2015

Determination of workspace is one of the main considerations in the design of any robot since the workspace geometry is considered a fundamental issue for robot design. This also plays a crucial role in trajectory planning. Among parallel manipulators, 6-DOF Stewart platforms is the most researched and widely used robot. However, till date there is no closed form expression of workspace volume for Stewart platform. In this paper, a novel method is proposed to find out the workspace volume of Stewart platform. In this paper, individual workspace of each leg of the manipulator (P-U-S) is determined and then translated by a common distance towards their geometrical center thus generating constant orientation workspace. To determine the workspace volume, geometric intersection of the six spheres is computed. This results in workspace of definite shape and size, whose volume is calculated using simple formulae. It is observed that the geometric way of determination of workspace area is computationally less tedious than the algebraic method. This also helps a lot for workspace optimization of such manipulators.
A sequential school based smoke prevention program in secondary school adolescents
Authors: Di Paco A. , Boffi R. , De Marco C. , Ambrosino N.
Published: November 2015

Background and Aim. The hazardous health effects of smoking and second-hand smoke are well known and have been confirmed in several studies. We wondered whether a school based programme involving media models such as those represented by famous soccer players and TV characters, was effective in prevention of smoking habit in secondary school adolescents. Methods. Since October 2006 to May 2007 an anonymous survey was submitted to 1382 secondary schools pupils. After completing the questionnaire all students of 42 out of 70 classes selected by the school principals underwent a prevention programme consisting of 1 hour lecture on smoke healthy hazard with educational material (slides, video, leaflets). Furthermore each pupil was given card games with significant pictures. Since October 2007 to May 2008 and Since October 2008 to May 2009 pupils underwent a 1 hour interactive lesson on smoke related health hazards respectively. On December 2007 pupils in study attended a theatre event with show business characters acting to smoke dissuasion. No intervention was performed on the 568 pupils of the other classes along all the same 2 school- year period (controls). Results. Among other results at the end of the 2-year program 4% pupils of study group and 14% of controls reported smoking habit (p = 0.001) whereas 7% and 27% (p = 0.001) of study and control pupils respectively ignored smoking induced dependence. Conclusion. A school based programme involving media models such as those represented by famous soccer players, TV characters, was effective in prevention of smoking habit in secondary school adolescents.
Smoking cessation treatment for COPD smokers: the role of counselling
Authors: Jiménez-Ruiz C.A. , Fagerström K.O.
Published: November 2015

Smoking cessation is the only therapeutic intervention that can prevent COPD smokers from the chronic progression of their disorder. The most important intervention for helping these smokers to quit is a combination of counseling plus pharmacological treatment. The characteristics of the counseling should be different depending if this intervention is offered to smokers with a previous diagnosis of COPD or if the intervention is offered to smokers who have been recently diagnoses with COPD. The counseling of patients who have been recently diagnosed should include: a) explanation of the direct relationship between smoking and COPD, b) encouraging these patients to quit and c) using of spirometry and measurements of CO as a motivational tools. The counseling of patients who have been previously diagnosed should include: a) encouragement to make a serious quit attempt, b) an intervention that increases motivation, self-efficacy and self-esteem, c) and the intervention should also control depression and be directed to weight gain control.
Severe pneumonia after intravesical BCG instillation in a patient with invasive bladder cancer: case report and literature review
Authors: Caramori G. , Artioli D. , Ferrara G. , Cazzuffi R. , Pasquini C. , Libanore M. , Guardigni V. , Guzzinati I. , Contoli M. , Rossi R. , Rinaldi R. , Contini C. , Papi A.
Published: November 2015

We present here the case of a 66 year old man with a severe bilateral community acquired pneumonia secondary to dissemination after an intravesical instillation of bacilllus Calmette-Guérin (BCG). Diagnosis was based on positive polymerase chain reaction (PCR) for mycobacterium tuberculosis complex in bronchoalveolar lavage and on the finding on transbronchial biopsy of non necrotising granulomas histopathologically similar to the granulomas found in bladder biopsies. These findings were confirmed using a validated real time PCR assay demonstrating the presence of the BCG genome in transbronchial and bladder biopsies.
Introducing some secular and feminist theological insights of body into theological conversation
Authors: Potgieter Raymond
Published: November 2015

Whether the conversation is casual or professional, words such as body, woman, and heart a repart and parcel of community conversation. However, the understanding of the meaning of a specific word such as body may prove to be elusive, vague or alternately take on a complexity often removed from ordinary conversation. Although the insights from Christian feminists have enriched the traditional theological understanding of the word body their insights are not always associated with the general use of the term. A richer understanding of the word results in recapturing the meaning of body, not only for women but also for society’s theological conversation and ‘body-talk’ as a whole.Ongeag of die gesprek informeel of professioneel is, bly die woorde liggaam, vrou en hart deel van die gemeenskapsgesprek. Die begrip of betekenis van ’n bepaalde woord soos liggaam, kan ontwykend vaag of alternatiewelik ’n kompleksiteit aanneem wat van gewone gesprekvoering verwyderd is. Feministe het onder andere ook van sekere woorde, waaronder besitreg geneem en dit aan kritiese teologiese ondersoek onderwerp. Hulle insig verryk die tradisionele begrip van die woord – nie net vir vroue nie, maar vir gemeenskapsteologie in die geheel.
Investigation of multidrug-resistant fatal colisepticaemia in weanling pigs
Authors: Fasina Folorunso O. , Bwala Dauda G. , Madoroba Evelyn
Published: November 2015

Escherichia coli is usually a benign commensal of the gut microflora. However, when E. coli acquires virulence genes it can multiply rapidly and cause disease through colonisation of the intestinal mucosa. Escherichia coli can become a significant pathogen in young pigs. We report an investigation of fatal colisepticaemia in weanling pigs from emerging farms where piglets and weaners were diarrhoeic and the mortality rate ranged between 15% and 70% in each litter. Faecal and tissue samples were processed for histopathology, bacteriology and molecular biology (multiplex and monoplex polymerase chain reaction) and we recovered enteroaggregative multidrug-resistant E. coli producing EAST-1 enterotoxin. An association between poor housing conditions and the observed cases was established and future management programmes were recommended to reduce the impact of such pathogens. Enteroaggregative E. coli is becoming a major problem in the pig industry. It therefore becomes necessary to establish the full impact of E. coli on the South African pig industry and to determine the geographic extent of the problem.
The role of physiotherapy in the treatment of HIV-related sensory neuropathy: The perceptions and referral practices of physicians
Authors: Steyl Tania , Shayo Felista T.
Published: November 2015

Background: HIV-related peripheral neuropathies are among the most prevalent chronic neurological disorders affecting persons living with HIV and AIDS. In order to improve the physical function and quality of life of those affected by the disease, a holistic or multidisciplinary approach, including physiotherapy, has been suggested for the management of neuropathic pain.Aim: The aim of this study was to explore the physicians’ perceptions regarding the role of physiotherapy in the management of patients with HIV-sensory neuropathy (HIV-SN) and their referral practices in Tanzania.Methods: A qualitative study design incorporating purposive sampling was employed in the study. A total of 10 physicians from a hospital in Tanzania agreed to participate in in-depth interviews.Results: Physicians had poor perceptions of the role of physiotherapy in the management of patients with HIV-SN. Their inadequate knowledge of the role of physiotherapy and the limited number of physiotherapists employed negatively influenced their referral of patients with HIV-SN for physiotherapy.Conclusion: In Tanzania, referral for physiotherapy is still dependent on medical doctors. Inter-professional learning is imperative for minimising the stereotypes that may exist across professions, hence the need to improve awareness of specific roles in patient management. This could improve knowledge of the role of other professionals in the management and rehabilitation of affected patients and consequently improve perceptions and facilitate referrals of patients with HIV-SN for more integrated care.
Об однозначном определении системы по части матрицы монодромии
Authors: Malamud Mark Mikhailovich
Published: November 2015

Рассматриваются системы дифференциальных уравнений первого порядка на конечном интервале с невырожденной диагональной матрицей $B$ при производной и суммируемой потенциальной матрицей $Q$, имеющей нулевую диагональ. Доказывается, что потенциальная матрица $Q$ однозначно определяется по матрице монодромии $W(\lambda)$. В случае $B=B^*$ указано минимальное число элементов матрицы $W(\lambda)$, достаточное для однозначного определения матрицы $Q$.
Некоторые неравенства для положительно определенных функций
Authors: Gorin Evgenii Alekseevich
Published: November 2015

Рассматриваются некоторые обобщения классического неравенства
$|f(x)-f(y)|^2\le2f(0)\{f(0)-\operatorname{Re}f(x-y)\}$ для положительно определенной комплексной функции $f$ на абелевой группе.
Influence of Head Orientation in Linear Measurement for Implant Planning in Cone Beam Computed Tomography
Authors: Shokri Abbas , Khajeh Samira , Khavid Atefeh , Tabari Sara , Yarmohammadi Shiva
Published: November 2015

Aim

Use of dental implants in edentulous patients has become a common treatment modality. Treatment of such implants requires radiographic evaluation, and in most cases several different imaging techniques are necessary in order to evaluate the height, width and the structure of bone at implant site. The aim of this study was to evaluate the influence of head orientation in linear measurement for implant planning in cone beam computed tomography (CBCT).

Materials and methods

In the present in vitro study, 11 human dry mandibles were used. The width and height of bone at the central, canine and molar teeth areas were measured on the left and right sides by using digital calipers (as gold standard) and on CBCT images with Reaxis option and no Reaxis. Data were analyzed with Statistical package for the social sciences (SPSS) 18, using pair t-test, Tukey test and intraclass correlation (ICC).

Results

Data were collected by evaluation of 11 skulls and 66 samples on the whole. There were no significant differences in bone width in any area in both Reaxis and no Reaxis option (p > 0.05). There were significant differences in bone height in the central (p = 0.005) and molar teeth areas (p = 0.010). The results did not show any significant differences between the observers (p = 0.329).

Conclusion

Using the Reaxis option does not affect the measurement of bone width, while use of this option can make a significant difference for height measurements.

How to cite this article

Shokri A, Khajeh S, Khavid A, Tabari S, Yarmohammadi S. Influence of Head Orientation in Linear Measurement for Implant Planning in Cone Beam Computed Tomography. J Contemp Dent Pract 2015;16(7):542-546.
A Rare Case of Mucoepidermoid Carcinoma ex Pleomorphic Adenoma arising in Minor Salivary Gland: Histopathological and Immunohistochemical Analysis
Authors: Daltoe Felipe Perozzo , Grando Liliane Janete , Meurer Maria Inês , Rivero Elena Riet Correa , Modolo Filipe
Published: November 2015

Mucoepidermoid carcinoma ex pleomorphic adenoma (MCxPA) is a rare salivary gland tumor predominantly found in major salivary glands. A case of MCxPA involving the soft tissue and bone of the retromolar region of a 26-year-old man is presented. The histopathological features revealed a neoplasm with predominance of pleomorphic adenoma (PA) elements, and presence of mucoepidermoid carcinoma malignant epithelial cells in several areas. Histochemical and immunohistochemical studies were positive for periodic acid Schiff, alcian blue, cytokeratins 7, 13, 14, and 19, Bcl-2, c-erbB-2, FGF-2 and maspin in the malignant areas. The patient underwent a partial resection of the left side of the mandible with neck dissection and MCxPA diagnosis was confirmed.

How to cite this article

Daltoe FP, Grando LJ, Meurer MI, Rivero ERC, Modolo F. A Rare Case of Mucoepidermoid Carcinoma ex Pleomorphic Adenoma arising in Minor Salivary Gland: Histopathological and Immunohistochemical Analysis. J Contemp Dent Pract 2015;16(7):603-606.
Comparison of Antimicrobial Activity between Chemical Disinfectants on Contaminated Orthodontic Pliers
Authors: Tonetto Mateus Rodrigues , da Silva Marcos André dos Santos , Kuga Milton Carlos , Bandeca Matheus Coelho , Pinzan-Vercelino Célia Regina Maio , Carvalho Maria Reggiani Azevedo , de Sousa Brito Carla Adriana Rodrigues , Campelo Viriato , Tavarez Rudys Rodolfo De Jesus
Published: November 2015

Aim

To compare the antimicrobial activity of the chemical substances—70% isopropyl alcohol, 2% glutaraldehyde (GTA) and 0.25% peracetic acid (PAA) in disinfecting orthodontic pliers contaminated in vitro with Streptococcus mutans, Staphylococcus aureus and Candida albicans.

Materials and methods

Distal end cutter pliers were divided into five groups: group 1 (negative control—sterilized pliers), group 2 (positive control—sterilized plier, subsequently contaminated), group 3 (disinfected with 70% isopropyl alcohol, friction method), group 4 (disinfected with 2% GTA, immersion method for 30 minutes), group 5 (disinfected with 0.25% peracetic acid (PAA), immersion method for 10 minutes). After the pliers were treated with one disinfectant and submitted to microbiological evaluation (by counting colony forming units), they were submitted to the same cleansing, sterilizing and contaminating processes, and were used in the following groups (crossover and washout study). The two-factor analysis of variance (ANOVA) test, followed by the Tukey test, was used to compare the groups.

Results

The results showed that there was no statistically significant difference between the three tested disinfectants.

Conclusion

Although there were no statistically significant differences between the disinfectants, the chemical agents 2% glutaraldehyde and 0.25% PAA were effective in inhibiting the growth of the three microorganisms tested; however, 70% isopropyl alcohol was unable to completely eliminate S. aureus.

Clinical significance

The chemical substances 2% glutaraldehyde and 0.25% PAA completely eliminated the microorganisms tested.

How to cite this article

Carvalho MRA, dos Santos da Silva MA, de Sousa Brito CAR, Campelo V, Kuga MC, Tonetto MR, De Jesus Tavarez RR, Bandéca MC, Pinzan-Vercelino CRM. Comparison of Antimicrobial Activity between Chemical Disinfectants on Contaminated Orthodontic Pliers. J Contemp Dent Pract 2015;16(8):619-623.
Effect of Three-wall Bony Defect along Various Root Surfaces on Position of Center of Resistance: A 3D Finite Element Analysis
Authors: Chachada Achint Devendra , Hazarey PV , Aley Mrunal Shyam , Atram Harish Keshaorao , Kharche Asmita
Published: November 2015

Introduction

Increase in adult orthodontic patients has increased the challenges faced by orthodontists, as they often present themselves with a varying degree of dental and periodontal compromise, in which the entire orthodontic treatment planning will revolve around maintenance and augmentation of supporting apparatus. One of the many factors to be considered during treating an adult patient is the height of alveolar bone and its effect on center of resistance (CRes).

Materials and methods

Eight 3D analytical models of upper central incisor were designed using ‘Solid Works Office Premium’. The models were subjected to 3 and 6 mm bone loss along all four surfaces, i.e. labial, lingual, mesial and distal. One Newton of retraction force was applied on labial surface of tooth on model number 1, 2, 5 and 6 and 1N of distalization force was applied to model number 3, 4, 7 and 8. The relative location of the CRes to the total root length was taken as 41.8% of total root length from the root apex. The ANSYS software was used to evaluate the change in CRes on all the models.

Results

It was observed that CRes shifted apically from its relative location (41.8% from apex); however, this shift was clinically insignificant. Minimum deflection of CRes, 0.0122 mm, was seen when a distalization force was applied on model with 6 mm bone loss on distal surface, while maximum deflection of 0.0245 mm was seen when retraction force was applied on model with 6 mm bone loss on labial surface.

Conclusion

The resultant displacement in position of center of resistance is negligible; hence, there is no need of changing biomechanics during orthodontic treatment for a tooth with three wall infrabony defects. However, it is necessary to further study other infrabony defects like two wall or one wall defect, and their effect on position of CRes.

How to cite this article

Chachada AD, Hazarey PV, Aley MS, Atram HK, Kharche A. Effect of Three-wall Bony Defect along Various Root Surfaces on Position of Center of Resistance: A 3D Finite Element Analysis. J Contemp Dent Pract 2015;16(8): 688-691.
An Intraoperative Site-specific Bone Density Device: A Pilot Test Case
Authors: Stefano Danilo Alessio Di , Arosio Paolo , Moschioni Monica , Banfi Luca Maria
Published: November 2015

Aim

This paper reports a case of all-on-four rehabilitation where bone density at implant sites was assessed both through preoperative computed tomographic (CT) scans and using a micromotor working as an intraoperative bone density measurement device.

Background

Implant-supported rehabilitation is a predictable treatment option for tooth replacement whose success depends on the clinician's experience, the implant characteristics and location and patient-related factors. Among the latter, bone density is a determinant for the achievement of primary implant stability and, eventually, for implant success. The ability to measure bone density at the placement site before implant insertion could be important in the clinical setting.

Case description

A patient complaining of masticatory impairment was presented with a plan calling for extraction of all her compromised teeth, followed by implant rehabilitation. A week before surgery, she underwent CT examination, and the bone density on the CT scans was measured. When the implant osteotomies were created, the bone density was again measured with a micromotor endowed with an instantaneous torque-measuring system. The implant placement protocols were adapted for each implant, according to the intraoperative measurements, and the patient was rehabilitated following an all-on-four immediate loading protocol.

Conclusion

The bone density device provided valuable information beyond that obtained from CT scans, allowing for site-specific, intraoperative assessment of bone density immediately before implant placement and an estimation of primary stability just after implant insertion.

Clinical significance

Measuring jaw-bone density could help clinicians to select implant-placement protocols and loading strategies based on site-specific bone feature

How to cite this article

Arosio P, Moschioni M, Banfi LM, Di Stefano DA. An Intraoperative Site-specific Bone Density Device: A Pilot Test Case. J Contemp Dent Pract 2015;16(8): 697-703.
On the ability of RegCM4 regional climate model to simulate surface solar radiation patterns over Europe: an assessment using satellite-based observations
Authors: Alexandri G. , Georgoulias A. K. , Zanis P. , Katragkou E. , Tsikerdekis A. , Kourtidis K. , Meleti C.
Published: November 2015

Abstract. In this work, we assess the ability of RegCM4 regional climate model to simulate surface solar radiation (SSR) patterns over Europe. A decadal RegCM4 run (2000–2009) was implemented and evaluated against satellite-based observations from the Satellite Application Facility on Climate Monitoring (CM SAF), showing that the model simulates adequately the SSR patterns over the region. The SSR bias between RegCM4 and CM SAF is +1.5 % for MFG (Meteosat First Generation) and +3.3 % for MSG (Meteosat Second Generation) observations. The relative contribution of parameters that determine the transmission of solar radiation within the atmosphere to the deviation appearing between RegCM4 and CM SAF SSR is also examined. Cloud macrophysical and microphysical properties such as cloud fractional cover (CFC), cloud optical thickness (COT) and cloud effective radius (Re) from RegCM4 are evaluated against data from CM SAF. Generally, RegCM4 underestimates CFC by 24.3 % and Re for liquid/ice clouds by 36.1 %/28.3 % and overestimates COT by 4.3 %. The same procedure is repeated for aerosol optical properties such as aerosol optical depth (AOD), asymmetry factor (ASY) and single-scattering albedo (SSA), as well as other parameters, including surface broadband albedo (ALB) and water vapor amount (WV), using data from MACv1 aerosol climatology, from CERES satellite sensors and from ERA-Interim reanalysis. It is shown here that the good agreement between RegCM4 and satellite-based SSR observations can be partially attributed to counteracting effects among the above mentioned parameters. The potential contribution of each parameter to the RegCM4–CM SAF SSR deviations is estimated with the combined use of the aforementioned data and a radiative transfer model (SBDART). CFC, COT and AOD are the major determinants of these deviations on a monthly basis; however, the other parameters also play an important role for specific regions and seasons. Overall, for the European domain, CFC, COT and AOD are the most important factors, since their underestimations and overestimations by RegCM4 cause an annual RegCM4–CM SAF SSR absolute deviation of 8.4, 3.8 and 4.5 %, respectively.
Uncertainty contributions to low flow projections in Austria
Authors: Parajka J. , Blaschke A. P. , Blöschl G. , Haslinger K. , Hepp G. , Laaha G. , Schöner W. , Trautvetter H. , Viglione A. , Zessner M.
Published: November 2015

Abstract. The main objective of the paper is to understand the contributions to the uncertainty in low flow projections resulting from hydrological model uncertainty and climate projection uncertainty. Model uncertainty is quantified by different parameterizations of a conceptual semi-distributed hydrologic model (TUWmodel) using 11 objective functions in three different decades (1976–1986, 1987–1997, 1998–2008), which allows disentangling the effect of modeling uncertainty and temporal stability of model parameters. Climate projection uncertainty is quantified by four future climate scenarios (ECHAM5-A1B, A2, B1 and HADCM3-A1B) using a delta change approach. The approach is tested for 262 basins in Austria. The results indicate that the seasonality of the low flow regime is an important factor affecting the performance of model calibration in the reference period and the uncertainty of Q95 low flow projections in the future period. In Austria, the calibration uncertainty in terms of Q95 is larger in basins with summer low flow regime than in basins with winter low flow regime. Using different calibration periods may result in a range of up to 60 % in simulated Q95 low flows. The low flow projections show an increase of low flows in the Alps, typically in the range of 10–30 % and a decrease in the south-eastern part of Austria mostly in the range −5 to −20 % for the period 2021–2050 relative the reference period 1976–2008. The change in seasonality varies between scenarios, but there is a tendency for earlier low flows in the Northern Alps and later low flows in Eastern Austria. In 85 % of the basins, the uncertainty in Q95 from model calibration is larger than the uncertainty from different climate scenarios. The total uncertainty of Q95 projections is the largest in basins with winter low flow regime and, in some basins, exceeds 60 %. In basins with summer low flows and the total uncertainty is mostly less than 20 %. While the calibration uncertainty dominates over climate projection uncertainty in terms of low flow magnitudes, the opposite is the case for low flow seasonality. The implications of the uncertainties identified in this paper for water resources management are discussed.
An Investigation of Teachers’ Perceptions of the Effects of Class Size on Teaching
Authors: Almulla Mohammed Abdullatif
Published: November 2015

This study investigates the perceptions of Saudi Arabian primary school teachers in Years 4, 5 and 6 and discusses the effects of class size on teaching. The data comes from 30 teachers who teach small classes in two private schools, and 37 who teach large classes in two state schools in Alhafouf, Saudi Arabia. The study discusses whether different numbers of students in class could have an impact on teachers’ perceptions and teaching practices. The data show that teachers in both small and large classes believe that class size has some impact on their teaching. Teachers in large classes report that they usually use a limited range of teaching methods, which tend to be more teacher-centred. The data show that all teachers in both small and large classes believe that class size has some impact on their teaching. In addition, the majority of participants say that they prefer to teach a class which contains 15 to 20 students. It has been highlighted in this study that there are many barriers and difficulties, especially with regard to lesson time, which most teachers in large classes could face regarding the management of students’ behaviour and the assessment of students’ performance. Empirical evidence suggests that class size is still the major aspect affecting teaching.
Solution of HIV and Malaria Coinfection Model Using Msgdtm
Authors: Ebenezer Bonyah , Awuah-Werekoh Kwasi , Acquah Joseph
Published: November 2015

In this paper, we investigate an epidemic model of HIV and Malaria co-infection using fractional order Calculus (FOC). The multistep generalized differential transform method (MSGDTM) is employed to obtain an accurate approximate solution to the epidemic model of HIV and Malaria co-infection disease in fractional order. A unique positive solution for HIV and Malaria co-infection is presented in fractional order form. For the integer case derivatives, the approximate solution of MSGDTM and the Runge–Kutta–order four scheme are compared. Numerical results are produced for the justification for this method.