bluuebunny/crossref_metadata_2025 huggingface dataset:
Hot stretch forming of titanium sheet by resistance heating
Authors: Li Xiaoqiang , Dong Hongrui , Guo Guiqiang , Li Dongsheng
Published: September 2018

Titanium alloys are important aerospace materials due to excellent comprehensive performance, but it is difficult to form at room temperature. Electrically assisted hot stretch forming is used to form the titanium panels of aircraft. This paper studies the effect of temperature, strain, stress relaxation time and cooling rate on forming accuracy by stress relaxation test, tensile test and forming experiment. It is shown that for the influence of temperature on forming accuracy, there is no large difference among 773K, 873K, 973K. And with increase of strain, the forming accuracy becomes lower. For the influence of stress relaxation time, there is no large difference among 0min, 15mins, 30mins. And with decrease of cooling rate, the forming accuracy is improved significantly. It’s concluded that when the temperature reaches a high level, temperature and stress relaxation time have no great influence on forming accuracy. And the forming accuracy is mainly influenced by strain and cooling rate. Electrically assisted hot stretch forming is an effective method to form titanium alloy. And the part with high forming accuracy can be obtained by adopting high temperature, low strain, proper stress relaxation time and low cooling rate.
Feasibility study of a novel hot stamping process for Ti6Al4V alloy
Authors: Kopec Mateusz , Wang Kehuan , Wang Yaoqi , Wang Liliang , Lin Jianguo
Published: September 2018

To investigate the feasibility of a novel hot stamping process for the Ti6Al4V titanium alloy using low temperature forming tools, mechanical properties of the material were studied using hot tensile tests at a temperature range of 600 - 900°C with a constant strain rate of 1s-1. Hot stamping tests were carried out to verify the feasibility of this technology and identify the forming window for the material. Results show that when the deformation temperature was lower than 700°C, the amount of elongation was less than 20%, and it also had little change with the temperature. However, when the temperature was higher than 700°C, a good ductility of the material can be achieved. During the forming tests, parts failed at lower temperatures (600°C) due to the limited formability and also failed at higher temperatures (950°C) due to the phase transformation. The post-form hardness firstly decreased with the temperature increasing due to recovery and then increased due to the phase transformation. Qualified parts were formed successfully between temperatures of 750 - 850°C, which indicates that this new technology has a great potential in forming titanium alloys sheet components.
Research on the Compound Process of Hot Stamping and Heat Treatment for Duralumin Alloy Fairing with Large Aspect Ratio: Experiment and modeling
Authors: Xu Lingzhi , Zhan Lihua , Huang Minghui , Guo Liang , Ma Ziyao
Published: September 2018

The compound process of hot stamping and solution quenching heat treatment (HFQ®) was utilized to fabricate hard aluminium fairing of high aspect ratio. A simulation model was established by MSC.Marc to optimize the shape and size of the blamk as well as the effects of process parameters, namely, initial temperature, stamping speed, blank holder force (BHF), on extreme final temperature and thickness distribution of formed component were investigated. The reliability of finite element simulation was proved by the hot stamping experiments with self-designed moulds under the optimize process parameters achieved by simulation results. The results indicated that the optimized blank is well deformed without flange wrinkle and broken round; the maximum cooling rate in quenching can inhibite the precipitation when the initial temperature ranges from 350 to 450℃; BHF effects dominated on thickness distribution and 10KN is the most reasonable value under the studied condition while the optimum stamping speed is 100mm•s-1. Compared with the thickness of the stamping trials and numerical simulation, the deviation is less than 3.6%. Furthermore, The desired mechanical property is achieved without significant inhomogeneity.
Springback prediction of CP2 titanium sheets in hydroforming with membrane diaphragm process with finite element method
Authors: Aydogan Cahit Sertac , Hatipoglu Hasan Ali , Keles Omer
Published: September 2018

This study aims to predict and to examine the springback of CP2 Titanium sheets in hydroforming with membrane diaphragm process, which is the branch of hydroforming process. The Hydroforming with Membrane Diaphragm was used for experimental investigation, in which specified CP2 titanium sheets were bent with various radii and angles on a specifically designed die. Springback results were then used to validate the finite element model constructed previously. Results show that the numerical model of this study can be used to predict the approximate springback values. Thus, the scrap quantities of the sheet metal titanium products can be reduced by making some modifications on the die, such as the springback compensation based on the obtained approximate springback values.
Investigation into the micro deep drawing capabilities of a specially engineered refined aluminium alloy
Authors: Dhal A. , Panigrahi S.K. , Shunmugam M.S.
Published: September 2018

During miniaturisation, size of the part comes close to grain size of the material. There is an overall decrease in the total number grains undergoing deformation and most of these are surface grains. Therefore, microscale deformation is marked by abnormal stress-strain response which limits the manufacturing capabilities of microforming. Two distinct phenomena responsible for this are: (i) dominance of single crystal deformation behaviour, and (ii) increased strain localisation due to incompatibly between surface and core grains during deformation. The present work attempts to neutralise these effects by increasing the number of grains in the deformation zone. This has been achieved by engineering refined microstructure in the materials. To develop the refined microstructure, cryorolling followed by controlled annealing treatment has been employed. Microscale deformation behaviour and microforming capabilities of the refined material have been compared with its coarse-grained counterpart by analysing their tensile curves and by post-mortem study of micro deep drawn components over a wide range of sample thicknesses. Material with fully recrystallised, equiaxed, strain-free refined microstructure is found to have the best strain hardening response both in micro and macro deformation domains. This property is also reflected in the micro deep drawing capabilities of the same material.
Improving the formability of magnesium by cushion-ram-pulsation
Authors: Rautenstrauch Anja , Luft Johannes , Birnbaum Peter , Baumann Markus , Ullmann Madlen , Kräusel Verena , Landgrebe Dirk , Kawalla Rudolf , Prahl Ulrich
Published: September 2018

The application of forming processes using lightweight magnesium alloys is known to be difficult with regard to minor formability caused by a small number of active slip systems, especially at low temperatures. However, a new approach for deep drawing at elevated temperatures considers flexible motion profiles of a servo-screw press. The so-called cushion-ram-pulsation (CRP) is a newly developed method of position-controlled motion. As a result, the process limitations for deep drawing are significantly extended. This study investigates the deep drawing process of AZ31 cups by variable motion profiles of cushion and ram, focusing on enhanced drawability. Therefore the initial AZ31 sheet was fabricated by twin-roll casting. Furthermore, the adjustment of the forming temperature for an improved forming process and optimized component properties are described. In addition, the results were evaluated in comparison to conventional deep drawing, and the superior technological potential will be outlined.
Material flow control in sheet-bulk metal forming processes using blasted tool surfaces
Authors: Merklein Marion , Löffler Maria , Gröbel Daniel , Henneberg Johannes
Published: September 2018

Highly-integrated and closely-tolerated functional components can be produced by sheet-bulk metal forming which is the application of bulk forming operations on sheet metals. These processes are characterized by a successive and/or simultaneous occurrence of different load conditions such as stress and strain states which reduce the geometrical accuracy of the functional elements. Thus, one main challenge within sheet-bulk metal forming is the identification of methods to control the material flow and thus to improve the product quality. One suitable approach is to control the material flow by local modifications of the tribological conditions. Within this study requirements regarding the needed adaption of the tribological conditions for a specific sheet-bulk metal forming process were defined by numerical investigations. The results reveal that a local increase of the friction leads to an improved die filling of the functional elements. Based on these results abrasive blasting as a method to modify the tool surface and thus influencing the tribological behaviour was investigated. For the determination of the tribological mechanism of blasted tool surfaces, the influence of different blasting media as well as blasting pressures on the surface integrity and the friction were determined. The correlations between surface properties and friction conditions were used to derive the mechanisms of blasted tool surfaces.
The influence of process parameters on the temperature development in the forming zone
Authors: Tröber Philipp , Welm Markus , Weiss Hannes Alois , Demmel Peter , Golle Roland , Volk Wolfram
Published: September 2018

Cold metal forming is a fast and economical way of producing a wide range of precise components. Its profitability mainly depends on part quality, process stability and service intervals of tools. As these factors are all determined by tool wear, detailed process knowledge is indispensable to maximize profitability by minimizing wear. One of the most crucial factors in this context is temperature. During every forming process, a temperature rise occurs between tool and workpiece due to frictional heating and a large part of plastic work dissipating into heat. This temperature affects the whole forming process but especially tool wear. Currently, there is little solid information about temperatures occurring during forming operations. Therefore, the temperature was measured based on varying process parameters in several embossing and blanking examinations. The use of a tool-workpiece-thermocouple enabled accurate and instantaneous measurement during the process. The results presented show the strong influence of process parameters on temperatures in the forming zone.
Influence of surface integrity on the plastic flow in analogous testing of 42CrMo4
Authors: Hild Rafael , Feuerhack Andreas , Trauth Daniel , Hoffmann Dennis C. , Kruppe Nathan C. , Brögelmann Tobias , Bobzin Kirsten , Klocke Fritz
Published: September 2018

Surface modification of workpieces for cold forming processes is common in industrial practice. Specific surface topographies manufactured by means of shot peening form lubricant pockets, which provide a continuous lubricating film throughout the process. Furthermore, hydrostatic as well as hydrodynamic lubrication effects emerge, which further reduce the friction during the process and protect the tool from wear effects. These effects are well researched and applied in order to enable cold forming processes. In dry forming processes, no lubricants are used, and the positive lubrication effects do not appear. Surface modifications by shot peening or knurling change surface integrity in terms of hardness, residual stresses and geometry. The effects of the changed surface integrity on the forming process are not researched. In tribometer tests, a hard and rough surface texture lead to a lower frictional shear stress, whereas a rather smooth and hard surface texture leads to a lower punch force in an extrusion process. The mechanisms between surface textures and the smoothing and forming process are unknown. Furthermore, findings of the tribometer tests cannot be fully transferred to the extrusion process. As in tribometer tests a pin is used as tool and in extrusion a whole die, a discrepancy between the most suitable surface texture for a friction reduction results out of different flow conditions. Still, the tribometer tests give a first reference on a surface pretreament. The paper deals with an investigation of surface textures in order to distinguish characteristics of surface textures respectively a friction reduction. By means of indentation tests of the quenched and tempered steel 42CrMo4 the plastic flow in dependency of different surface integrities are researched. The results show which characteristics help to lower the punch force the most, so for further investigations an optimized surface modification is set up in order to enable a dry metal forming process.
Probing the potential of structured and surface functionalized tools for dry cold forging of aluminium
Authors: Teller Marco , Ross Ingo , Prünte Stephan , Temmler André , Küpper Moritz , Poprawe Reinhart , Schneider Jochen M. , Hirt Gerhard
Published: September 2018

In order to reduce friction and wear in cold forging of aluminium and its alloys a tremendous amount of lubricants is used. The main task of the liquid lubricants is the separation of tool and workpiece surfaces to avoid adhesion and abrasion. From an ecological and economical point of view, a reduction of the consumption of lubricants is meaningful. Novel surface modification techniques have been investigated to enable dry cold forming. In previous work, a reduced wear by adhesion of aluminium to an AISI H11 ESR tool steel surface was detected for a combination of laser polishing and a subsequent surface functionalization. Here, structured surfaces combined with surface functionalization are investigated regarding their wear behaviour. Therefore, different structures are realized on AISI H11 ESR tool steel surfaces by laser structuring. These structures are aligned parallel and perpendicular to the material flow direction. Furthermore, different structure depths are generated. It is evident that the laser induced surface melting causes both, a reduced micro roughness as well as a homogenized elementary distribution. Moreover, the surfaces are functionalized with an octadecylphosphonic acid selfassembled monolayer (C18PA-SAM). The SAM’s distal alkyl termini functionalize the tool steel surface und thus only weak van-der-Waals interactions are present in the aluminium-tool steel interface rendering an interaction, which is expected to be similar to the interaction in conventionally lubricated aluminium forming. Finally, the surfaces are appraised regarding their wear behaviour in a compression-torsion-wear tribometer. The different experimental results document the potential of the here investigated combined tool surface modification. Although, the performance of a lubricated process is not completely reached a reduction in friction and wear can be achieved compared to unmodified tools.
Reducing Abrasive Particle Generation in Dry Rotary Swaging by Utilizing DLC Hard Coated Dies
Authors: Böhmermann Florian , Herrmann Marius , Riemer Oltmann , Kuhfuss Bernd
Published: September 2018

The emphasis of this paper is the investigation of the impact of the diamond like carbon (DLC) hard coating system on the amount of abrasive particles being generated during dry rotary swaging. Rotary swaging experiments applying coated and uncoated macro structured forming dies were carried out against aluminum and steel work pieces varying the process parameter feed velocity. It was found that DLC coatings effectively reduce the generation of abrasive particles from the work piece. For dry machining of aluminum the amount was reduced to a tenth of the original quantity achieved with uncoated dies. The results are discussed with regard to the mechanics of interfacing surfaces. Additionally, forming dies exhibiting macro structures surfaces of improved design were introduced and applied in dry rotary swaging experiments, which allowed minimizing the abrasive particle generation.
A new approach for dry metal forming: CO2 as volatile lubrication in combination with hard and low friction coatings
Authors: Umlauf Georg , Hasselbruch Henning , Henze Jan Hinnerk , Barz Jakob , Mehner Andreas
Published: September 2018

Nowadays, it is more important than ever to meet the increasing technical and statutory requirements and to develop new process strategies. In sheet metal forming the low consumption of oil lubrication gets an increasingly important role. The aim in sheet metal forming is to reduce the amounts of lubricants. In the long term, the future sheet metal processing should be able to completely dispense without mineral oil-containing lubricants. Two promising approaches for a dry process design are combined in this paper for the first time and the fundamental feasibility of this new hybrid technology is shown. On the one hand, a novel approach for temporary lubrication of deep-drawing processes with CO2 as a volatile medium is used. On the other hand, it is supported by the application of an additional hard coating system such as a silicon nitride (Si3N4) or tungsten doped a-C:H multilayered (Cr/CrNx/a-C:H:W/a-C:H) coating system to further reduce tool wear and wear debris of the formed sheets made of DC04 (mat. no.: 1.0338). The results show a low coefficient of friction and reduced wear. Especially for the carbon coating system, there is minor tool wear at a higher surface pressure. By means of the graphite constituent, even a smoothening of the roughness peaks can be recorded. The next step would be the implementation of this hybrid technology on a tool for deep drawing a rectangular cup.
Chances and Limitations in the Application of Laser Chemical Machining for the Manufacture of Micro Forming Dies
Authors: Messaoudi Hamza , Böhmermann Florian , Mikulewitsch Merlin , von Freyberg Axel , Fischer Andreas , Riemer Oltmann , Vollertsen Frank
Published: September 2018

Laser chemical machining, a non-conventional processing method based on thermally activated electrochemical material dissolution, represents a promising technology for manufacturing metallic dies for micro forming applications. Prior to widespread industrial acceptance the machining quality of laser chemical machining should be characterized. For this purpose, laser chemical machining is compared with micro milling regarding both the dimensional accuracy and the surface quality. Therefore, square micro cavities exhibiting side walls between 100 μm and 400 μm in length and 60 μm in depth are machined with both manufacturing processes into the cobalt-chrome alloy Stellite 21. The geometrical features are investigated using laser-scanning confocal microscopy and scanning electron microscopy. On the one hand, laser chemical machining is more suitable for manufacturing cavities with dimensions < 200 μm due to higher shape accuracy with stable mean edge radii of (11.2 ± 1.3) μm as a result of roughing and finishing steps. On the other hand, the finish quality of micro milling with mean surface roughness Sa of 0.2 μm could not be achieved with laser chemical machining due to in-process induced waviness. Finally, the metallographic analysis of the surface-near layers reveals that both manufacturing processes ensure gentle machining without any noticeable micro structural impact.
Using Support Vector Machine to Improve Ultrasonic Pulse Velocity Test for Concrete
Authors: Loan Ngo Tu Quynh , Wang Yu-Ren
Published: September 2018

In the construction industry, to evaluate the compressive strength of concrete, destructive and non-destructive testing methods are used. Non-destructive testing methods are preferable due to the fact that those methods do not destroy concrete samples. However, they usually give larger percentage of error than using destructive tests. Among the non-destructive testing methods, the ultrasonic pulse velocity test is the popular one because it is economic and very simple in operation. Using the ultrasonic pulse velocity test gives 20% MAPE more than using destructive tests. This paper aims to improve the ultrasonic pulse velocity test results in estimating the compressive strength of concrete using the help of artificial intelligent. To establish a better prediction model for the ultrasonic pulse velocity test, data collected from 312 cylinder of concrete samples are used to develop and validate the model. The research results provide valuable information when using the ultrasonic pulse velocity tests to the inputs data in addition with support vector machine by learning algorithms, and the actual compressive strengths are set as the target output data to train the model. The results show that both MAPEs for the linear and nonlinear regression models are 11.17% and 17.66% respectively. The MAPE for the support vector machine models is 11.02%. These research results can provide valuable information when using the ultrasonic pulse velocity test to estimate the compressive strength of concrete.
Peak Discharge and Hydrograph Assessments Induced by Heavy Rainfall Events Using Tank Model
Authors: Hsu Yen-Kun , Peng Szu-Hsien , Tsai Chiao-Wen
Published: September 2018

Tank Model is a kind of simulation of rainfall movement in soil horizon. With the runoff and piping rate, the peak discharge could be effectively calculated. Having 17 rain gauge stations in 13 debris flow events during 1996-2010 as the studied cases, the peak discharge at 12 control points along Chenyulan River is simulated. Furthermore, the data in Neimaopu discharge station is established parameters of Tank Model to estimate the peak discharge in Shenmu Village. By comparing with the parameters of Shueili Station and Japanese Granite, the mean error of the parameter in this study is 51.0%, which is better than those of Japanese Granite 189% and Shueili discharge stations 251%. The parameter in this study appears the highest in allowance analysis, showing that it is more suitable for simulating the peak discharge than the other two. In spite that the percentage of the three parameters is still low, Shenmu Village could be ignored as it locates in the sub-basin of Chenyulan River with few factors. The parameters of Tank Model are applied to transform average rainfall into hydrograph so as to solve the problem of no discharge records when analysing the areas with various debris flow simulation programs.
Design Analysis of Overhead Crane for Maintenance Workshop
Authors: Sitthipong Siva , Meengam Chaiyoot , Chainarong Suppachai , Towatana Prawit
Published: September 2018

This research aimed to study the design of the overhead crane of a small fishing boat maintenance factory according to the building and functional requirements of the project based on the ASME B30.2-2005 Standard. The results of the study showed that the design of the runway with steel structure BS: 5950: 2000 grade s460 provided vertical and horizontal deflection values of 4.96 and 16.62 respectively that did not exceed the allowed deflection. It is strong enough for use in construction when the stresses on the beam bridge were analysed by the finite element program compared with the strength of the reinforced steel providing a safety value of 1.83.
Design and Analysis of a Wind Turbine Blade with Dimples to Enhance the Efficiency through CFD with ANSYS R16.0
Authors: Rajaram Narayanan M. , Nallusamy S. , Ragesh Sathiyan M.
Published: September 2018

In the global scenario, wind turbines and their aerodynamics are always subjected to constant research for increasing their efficiency which converts the abundant wind energy into usable electrical energy. In this research, an attempt is made to increase the efficiency through the changes in surface topology of wind turbines through computational fluid dynamics. Dimples on the other hand are very efficient in reducing air drag as is it evident from the reduction of drag and increase in lift in golf balls. The predominant factors influencing the efficiency of the wind turbines are lift and drag which are to be maximized and minimized respectively. In this research, surface of turbine blades are integrated with dimples of various sizes and arrangements and are analyzed using computational fluid dynamics to obtain an optimum combination. The analysis result shows that there is an increase in power with about 15% increase in efficiency. Hence, integration of dimples on the surface of wind turbine blades has helped in increasing the overall efficiency of the wind turbine.
Novel Materials Synthesized from Red Mud, Bagasse, and Bentonite for Gas Treatment by CO2 Absorption
Authors: Hoc Thang Nguyen , Luong Ngoc Nguyen Hoang , Thi Nha Uyen Vo , Trung Kien Pham
Published: September 2018

Carbon dioxide (CO2) is a gas which causes both impact to atmosphere (one of greenhouse gases) and decrease heating value of gaseous fuel (such as natural gas, biogas, landfill and sewage gas). Hence, there are many investigations to find solutions for gas treatment and carbon dioxide absorption from researchers. Catalyst or synthesized materials is to optimize processes of CO2 treatment and absorption to obtain the best benefit for factories and community. This study utilized industrial wastes of red mud and bagasse in combination with bentonite to synthesis the novel material (absorbent) responding requirements for the process of gas treatment. More specially, raw materials are impacting negatively on the environment. In which, red mud is solid waste of Bayer process from bauxite mining which is being the hard problem to have solutions for its management and utilization and bagasse is industrial waste of sugar factories. Wet pressing method was applied to form the absorbent samples by mixing red mud, bagasse, bentonite, and water in mixtures. The samples were put in furnace for heating process at 300°C for 2 hours. The final samples were characterized for microstructure using X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). And then the absorbents were tested for gas absorption capacity of carbon dioxide. The results showed a potential application of the novel absorbent materials for gas treatment.
Investigation of tribo-mechanical properties and structure of specimens obtained by selective laser melting of stainless steel powders
Authors: Belyaev Leonid , Zhdanov Aleksey , Morozov Valentin
Published: September 2018

The article presents experimental data about the quality parameters of the stainless steel three-dimensional parts obtained by the selective laser sintering procedure. The results of the porosity, tribological properties, tensile test, hardness measurement and density for different values of the focal point position during the engineering process of the three-dimensional parts sintering were given. For parts made from steel powder CL20ES at a laser radiation power of 200 W in a different focal length range, it is demonstrate that the specimens with the highest density and microhardness values are obtained during the synthesis by using a converging laser beam.
Integrated Product and Process Development of Clutch Friction Material Using Quality Function Deployment Processes
Authors: Yan Zhengfeng , Tu Guangping , He Jiajun
Published: September 2018

Using an improved quality function deployment (QFD) process, an integrated product and process development method was proposed for the clutch friction material, one key part of driveline. The importance ratings of customer requirements for the clutch friction material was calculated and synthesized through the reasonable selection of respondents and the method to determine customer requirements based on importance of rough analytic hierarchy process (AHP) in QFD. Using improved QFD decomposition model, the quality house between customer requirements and part features, process matrix and the key process control sample table were established. The method can be widely used in the development of other key parts.
The Thermal Hydraulic Performance of Wavy PCHE with Different Materials and Geometric Parameters
Authors: Li Yunzhu , Xie Yonghui , Zhang Di
Published: September 2018

The printed circuited heat exchanger (PCHE) contain several different channel configurations, such as straight channel, zigzag channel and wavy channel. The wavy channel has better thermal performance than the straight channel and better hydraulic performance than the zigzag channel. This paper explores the thermal hydraulic performance of wavy channel PCHE. The numerical analysis of the PCHE in different materials and geometric parameters are conducted by computational fluid dynamics (CFD) tool. The materials applied in simulations involve Alloy617, Titanium Grade 3, Carlson 2205, UNS S30400 and Sandvik 253A. The results show that the materials have little effect on the thermal-hydraulic performance. The geometric parameters include channel degree varying from 10°to 50°, channel amplitude varying from 1mm to 5mm and the radium of hot/cold channel varying from 0.4mm to 2.0mm. It is found that the larger radium of hot channel results out the lower Nusselt number and lower fanning-friction factor while the higher radium of cold channel produces the higher Nusselt number and lower fanning-friction factor. The larger channel amplitude indicates the higher fanning-friction factor and lower Nusselt number. The larger channel degree indicates the higher fanning-friction factor, and higher Nusselt number.
Moderate-intensity Arm-cranking Exercise may not Improve Arterial Function in Healthy Adult Men
Authors: Miura Hajime , Ishikawa Miduki , Deguchi Kenichi
Published: September 2018

Endurance exercises, such as cycling or running, are useful for improving arterial function. However, people suffering from partial paralysis or arthritis are unable to perform these kinds of lower-limb exercises. In the present study, we explored the acute effect of upper-arm exercise on arterial stiffness in healthy men. Fourteen healthy adult men performed two experimental trials. The order of experiments was randomized between a 30-min arm-cranking exercise at 50% V̇O2max (A-trial) and a 30-min leg-cycling exercise at 50% V̇O2max (C-trial). The brachial to ankle pulse wave velocity (baPWV), brachial systolic/diastolic blood pressure and heart rate were obtained with subjects in the supine position. The baseline hemodynamic values were not markedly different between the two trials. Compared with the baseline value, the baPWV was significantly reduced at 30 and 60 min after the C-trial. In the A-trial, however, there were no significant changes in the baPWV throughout the trial. These results indicate that acute 50% V̇O2max arm-cranking exercise induced relatively little change in the baPWV, which was the opposite of the finding observed with leg-cycling exercise. Therefore, in order to improve arterial function via aerobic upper-arm exercises, the exercise mode/intensity or other approaches should be considered.
Catecholamine-Induced Cardiomyopathy in Pheochromocytoma: How to Manage a Rare Complication in a Rare Disease?
Authors: Santos Jenn Rachelle U. , Brofferio Alessandra , Viana Bruna , Pacak Karel
Published: September 2018

Pheochromocytomas and paragangliomas (PHEOs) are rare neuroendocrine tumors. Clinical manifestations include different cardiovascular signs and symptoms, which are related to excessive secretion of catecholamines. Catecholamine-induced cardiomyopathy in PHEO (CICMPP) is a rare but dreaded complication of PHEO. Once patient is diagnosed with this condition, the prognosis is worse and a surgical risk is much higher than expected. This article focuses on how catecholamines affect the heart and the pathophysiologic mechanism of CICMPP. The cardiovascular responses to catecholamine depend mostly on which catecholamine is released as well as the amount of catecholamine that is released. The acute release of norepinephrine and epinephrine from PHEO increases heart rate, systemic vascular resistance, myocardial contractility, and reduces venous compliance. The excessive adrenergic stimulation by catecholamine results in severe vasoconstriction and coronary vasospasm, myocardial ischemia, and subsequently damage, and necrosis. Chronically elevated catecholamine levels lead to significant desensitization of cardiac β-adrenoceptors. The increased levels of the enzyme β-adrenoceptors kinase (βARK) in the heart seems to mediate these biochemical and physiological changes that are consistently correlated with attenuated responsiveness to catecholamine stimulation. Through these mechanisms different types of cardiomyopathy (CMP) can be formed. This review discusses extensively the 3 types of cardiomyopathies that can be present in a PHEO patient. It also provides the clinical presentation and diagnostic and therapeutic algorithm in managing patients with CICMPP.
Intramedullary Fixation of Distal Radius Fractures Using CAGE-DR Implant
Authors: Rancy Schneider , Malliaris Stephanie , Bogner Eric , Wolfe Scott
Published: September 2018

Purpose CAGE-DR implant is a novel Food and Drug Administration approved intramedullary fracture fixation device used for distal radius fractures. We examine a series of 22 patients and report the outcomes with this device.

Materials and Methods A total of 24 patients with distal radius fractures (8 articular AO type C1/C2; 16 extra-articular AO type A2/A3) underwent open reduction and internal fixation (ORIF) using CAGE-DR implant by a single surgeon. Data including fracture type, angle of displacement, radiographic consolidation, grip strength, wrist range of motion (ROM), patient-rated wrist evaluation (PRWE), and Visual Analog Scale (VAS) pain scores were recorded at time of surgery and at standard follow-up.

Results All 24 patients underwent uneventful ORIF. At first follow-up visit (9 days), all patients had full digital ROM (measured as 0 cm tip-to-palm distance). Two patients were lost to follow-up. Eighteen of the remaining 22 patients had sufficient radiographic follow-up and all 18 demonstrated healing. At latest follow-up (mean 9.7 months, range, 3–20), VAS pain scores averaged 0.6 (range, 0–8) and PRWE averaged 12.1 (range, 0–53.5). Grip strength of the operated hand averaged 58 lbs (range, 20–130). ROM included: wrist flexion 73° (50–95), wrist extension 78° (60–110), pronation 77° (60–90), supination 79° (60–90), ulnar deviation 31° (5–45), and radial deviation 17° (10–30). Three patients underwent screw removal to prevent tendon irritation. One patient underwent hardware removal due to prominence on imaging but was asymptomatic. There were otherwise no major complications, including complex regional pain syndrome, in the series to date.

Conclusion The CAGE-DR fracture fixation system is a promising alternative to established methods of distal radius internal fixation. This series has a low reported pain score starting immediately postoperatively and a low complication rate. This novel device is a promising option for internal fixation of displaced distal radius fractures with a low complication profile.

Level of Evidence This is a level IV, therapeutic study.
Epigenetik - Vermittlung zwischen Anlage und Umwelt
Authors: Zerres K.
Published: September 2018

Die Erforschung der molekularen Ursachen psychischer Eigenschafen oder Erkrankungen ist schwierig. Trotz intensiver Forschung ist über deren molekulare Basis wenig bekannt. Es steht außer Frage, dass an der Entstehung eines spezifischen Phänotyp viele Faktoren beteiligt sind. Bisher galt, dass hierfür neben einer komplexen polygenen erblichen Basis exogene Einflussfaktoren verantwortlich sind. Die Schwierigkeit, die verantwortlichen Gene zu identifizieren aber auch Hinweise für die Weitergabe erworbener Zustände der Genregulation haben die Epigenetik in den letzen Jahren zu einem zentralen Forschungsgegenstand werden lassen. Das faszinierende Gebiet der Epigenetik beschäftigt sich mit der Analyse von Veränderungen von Phänotypen, die nicht Ergebnis von Veränderungen der DNA-Sequenz sind. Stattdessen können andere Faktoren wie Umwelteinflüsse die Expression spezieller Gene beeinflussen und Prozesse wie Entwicklung, Verhalten und Krankheitsmechanismen beeinflussen. Epigenetische Veränderungen können als eine Art Speichermedium über längere Zeit, unter Umständen über mehrere Generationen hinweg als sog. Transgenerationeneffekte wirksam werden.
Informatics – electronic diagnostics and therapy
Authors: Noakes P. , Byrne P.
Published: September 2018

Mental health professionals did not ask for it, but the proliferation of health informatics and the integration of connectivity into our daily lives will facilitate and improve mental health outcomes – provided change is clinician-driven. To date, no one informatics system achieved dominance and there is no consensus about how to proceed. Key systems’ components are identified. There are multiple technical, clinical, ethical and financial considerations that have delayed the routine use of these systems even in highly developed health services. Several interacting systems are discussed across general medical and mental health services. Informatics can assist with the diagnosis of some mental health conditions (anxiety, mood and substance misuse disorders), and a balance needs to be struck between excessive self-diagnoses and empowered patients. Allied systems, for example telemedicine, can assist clinicians in physical and many mental health disorders, but less so, severe enduring mental illness. Computerised therapies have a growing evidence base but may not suit every patient and all disorders. Once electronic databases are established across psychiatry, they will be used outside the clinical arena to pursue diverse research and economic agendae, with other uses as yet undefined. We conclude by speculating on possible future developments.
Refugees and asylum seekers in Europe
Authors: Kastrup M. C. , Schouler-Ocak M.
Published: September 2018

Background: European countries are the main receiving countries of immigrants such as refugees and asylum seekers belonging to ethnic minority groups due to a global increase in social and political instability as well as socio-economic conflicts. Both the number of ethnic minority groups and the number of people with mental disorders are therefore growing significantly. The current healthcare services are not prepared for this specific population of mentally ill immigrants or ethnic minority groups. Mental health care for immigrant patients is lacking in cultural competence and legislation related to access to and utilisation of health services varies from country to country. Aim: This article attempts to give an overview of the current mental health situation of ethnic minority groups, especially refugees and asylum seekers, in Europe.
Psychische Erkrankungen im Kindes- und Jugendalter und ihre Auswirkungen auf das Erwachsenwerden
Authors: Vloet T. D. , Konrad K. , Herpertz-Dahlmann B.
Published: September 2018

Entwicklungsprozesse haben für die Entstehung und den Verlauf kinder- und jugendpsychiatrischer Störungen eine große Bedeutung. So manifestieren sich einige erst in bestimmten Altersphasen oder nehmen in der Häufigkeit mit zunehmender Reife wieder ab. Viele Entwicklungsverläufe reichen aber auch bis in das Erwachsenenalter hinein. Der vorliegende Artikel stellt zunächst eine Klassifikation kinder- und jugendpsychiatrischer Störungen in Abhängigkeit distinkter Entwicklungs- und Verlaufsaspekte dar. Anhand von drei Störungsbildern werden exemplarisch verschiedene Entwicklungsverläufe skizziert: Währen die Autismusspektrumsstörungen früh beginnen und oft zu lebenslangen Beeinträchtigungen führen, können Reifungsprozesse bei den Aufmerksamkeitsdefizit-/Hyperaktivitätsstörungen die Ausprägung der Symptomatik im Verlauf vermindern. Innerhalb der heterogenen Gruppe von Störungen des Sozialverhaltens bestehen erhebliche Unterschiede zwischen Entwicklungspfaden, die teilweise eine dauerhaft zunehmende Symptomatik von der Kindheit bis in das Erwachsenenalter hinein zeigen. Generell liegen z.T. bereits im Kindes- und Jugendalter übergreifende Beeinträchtigungen vor, die im Verlauf die Bewältigung notwendiger Entwicklungsaufgaben erschweren und zu umfangreichen Einschränkungen im Erwachsenenalter führen können. Es wird in diesem Zusammenhang die Bedeutung einer bereits im Kindes- und Jugendalter einsetzenden Therapie betont.
Leitlinien als Mittel der Qualitätssicherung in der Versorgung psychischer Störungen in Deutschland
Authors: Großimlinghaus I. , Janssen B.
Published: September 2018

Ausgangslage: In der Versorgungspraxis von Menschen mit psychischen Störungen sind Leitlinien externe Orientierungshilfen für Behandler und für von psychischen Erkrankungen Betroffene, die den aktuellen evidenz- und konsensbasierten Wissensstand zur best-möglichen Diagnostik und Therapie psychischer Störungsbildern darstellen. Methodik: Im Rahmen der Qualitätssicherung in der Psychiatrie kann die Konformität mit Leitlinienempfehlungen als ein Kriterium für eine qualitativ gute Versorgung angesehen werden. Wichtig bei der Verwendung von Leitlinien im Rahmen der Qualitätssicherung ist dabei nicht nur deren methodische Hochwertigkeit sowie die Einbeziehung aller wichtigen Akteure im Leitlinien-Entwicklungsprozess, sondern auch deren Implementierbarkeit. Ziele: Der vorliegende Artikel beschreibt die Relevanz von Leitlinien in der Qualitätssicherung in der Psychiatrie und stellt beispielhaft Projekte dar, die sich mit der Implementierung von Leitlinien befassen.
Die Aktualisierung der DGPPN S3-Leitlinie Schizophrenie - aktueller Stand
Authors: Wobrock T. , Großimlinghaus I. , Zielasek J. , Janssen B. , Reich-Erkelenz D. , Kopp I. , Gaebel W. , Falkai P. , Hasan A.
Published: September 2018

Ausgangslage: Es gibt seit 2006 in Deutschland eine Leitlinie für die Behandlung der Schizophrenie auf dem S3-Niveau der Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften (AWMF). Fragestellung: Die im Jahre 2006 von der Deutschen Gesellschaft für Psychiatrie und Psychotherapie, Psychosomatik und Nervenheilkunde (DGPPN) publizierte S3-Leitlinie Schizophrenie befindet sich derzeit in einem umfangreichen Revisionsprozess. Die Notwendigkeit der Aktualisierung ergibt sich daraus, dass seit 2006 eine Vielzahl neuer klinischer Studien durchgeführt und publiziert worden sind, die eine neue Bewertung der Evidenzen für viele Bereiche erfordern. Daneben wurden viele methodisch hochwertige Meta-Analysen publiziert, die in verschiedenen Bereichen der Therapie eine Anpassung der Evidenzbewertung gebieten. Ziele: Es stehen zunehmend Fragen nach einer verbesserten Funktionsfähigkeit im Alltag, dem subjektiven Wohlbefinden und der Lebensqualität im Fokus der klinischen Praxis. Diese sehr relevanten klinischen Endpunkte sind in der letzten Version der S3-Leitlinie zwar erwähnt worden, besaßen aber noch nicht die heute gesellschaftlich und im Fach geforderte Relevanz.
Leitlinien in der hausärztlichen Praxis – das Beispiel Depression
Authors: Gensichen J. , Herrmann M.
Published: September 2018

Hintergrund: Hausärzte spielen eine zentrale Rolle beim Erkennen und bei der Behandlung depressiver Beschwerden. Der Entwicklung und Implementierung von Leitlinien kommen seit Ende der 90er-Jahre eine wachsende Bedeutung zu bei der Gestaltung von Versorgung über alle Bereiche hinweg. Ziel: Der vorliegende Beitrag diskutiert die Besonderheiten hausärztlicher Versorgung am Beispiel der Depression. Beschwerden werden im hausärztlichen Kontext aus dem lebensweltlichen Bezug heraus betrachtet, spiegeln die subjektive Sicht auf Krankheit der Patienten (Illnessperspektive) und reflektieren diese vor dem Hintergrund medizinischer Klassifikationssysteme (Diseaseperspektive). Der Beitrag geht der Frage nach, inwieweit die bisherige Leitlinienentwicklung diese Besonderheiten ausreichend berücksichtigt. Ergebnisse: Überlegungen dazu dienen der weiteren sektorenübergreifenden Leitlinienentwicklung, -evaluierung und -implementierung – kurz der gemeinsamen Patientenversorgung.
Managing Superficial Distal Medial Collateral Ligament Insufficiency in Primary Total Knee Arthroplasty Using Bone Staples
Authors: White Kevin T. , Fleischman Andrew , Ackerman Colin T. , Chen Antonia F. , Rothman Richard H.
Published: September 2018

Superficial medial collateral ligament (MCL) injury is an occasional intraoperative complication during total knee arthroplasty (TKA) that can lead to failure. Although previous studies have recommended complex repair or conversion to a constrained implant, the authors evaluated results of superficial distal MCL reapproximation using bone staples. Records of 31 patients who underwent staple reapproximation for superficial MCL avulsion from the tibial attachment during primary TKA from 2005 to 2015 were reviewed. They were compared with 685 patients who underwent uncomplicated TKA (primary control) and 18 who underwent revision TKA for instability (secondary control). Subjective knee instability was assessed with a patient questionnaire, and other end points included revision for instability or stiffness and manipulations under anesthesia. The authors prospectively collected Knee injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale satisfaction scores. The mean follow-up was 2.6 years. No patients treated with staple repair required revision for instability, whereas two patients were revised in the primary control. Subjective instability was reported in 19.2% of staple repair patients compared with 24.2 and 46.2% of patients in the primary and secondary controls. The mean KOOS for the staple group was 71.7 points, 77.3 for the primary control, and 49.3 for the secondary. KOOSs for the staple group were 5.6 points lower than the primary control, but 22.4 points higher than the secondary. Staple reapproximation is a simple and effective method for repairing the superficial distal MCL in primary TKA. The rate of instability and functional outcomes was comparable to uncomplicated primary TKA.
Knowledge and awareness of Hepatitis B among first year Undergraduate Students of Three Dental Colleges in Haryana
Authors: Bansal Mohit , Vashisth Shelja , Gupta Nidhi
Published: September 2018

Objective- To assess the Knowledge and awareness of Hepatitis B among first year undergraduate dental students of Haryana. Materials and Method- A cross sectional study was conducted in three colleges among 232 undergraduate dental students using a close ended questionnaire. Results- 84.9 % of the students were aware regarding the spread of the disease. 52.2% of the students had got their initial vaccination while 23.7 % of the student had complete vaccination against Hepatitis B. Conclusion- The overall knowledge and awareness regarding Hepatitis B was found to be lacking among dental students.
Orthodontic-Periodontic Interdisciplinary Approach
Authors: Kaur Bhullar Mandeep , Nirola Ashutosh , Singh Uppal Amandeep , Kaur Bhullar Mandeep
Published: September 2018

In the last years, a significant development has taken place in the orthodontic treatment of adult Patients. Adult orthodontics is different than that for children because in adults there is virtual no more growth and because there are changes in the tooth supporting structures: the periodontium. The orthodontic treatment is carried out through the medium of periodontium so a healthy tooth supporting system is the essential prerequisite for carrying out the orthodontic treatment. At the same time, as the tooth is moving under the effect of orthodontic force, various changes occur in the periodontium under the effect of force. So, it is important that the orthodontic treatment is periodontally compromised patient be considered separately as they are more prone to further bone loss; the reduced periodontium cannot sustain further loss without the potential loss of teeth. The reduced periodontal support dictates altered treatment design, mechanics and retention. At the same time it is important to consider the limits of periodontium while carrying out orthodontic treatment so that there is no damage due to inadvertent intervention.