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The current study presents the effect of the backbone as an important binder component on the mechanical, rheological, and thermal properties of Aluminium (Al) alloy feedstocks. A thermoplastic elastomer (TPE) main binder component was blended with either polypropylene (PP), grafted-maleic anhydride-PP (PPMA), or grafted-maleic anhydride-PPwax (PPMAwax) plus PP, as the backbone. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were performed to investigate the thermal properties of binder systems and feedstocks. Fourier-transform infrared (FTIR) spectroscopy was used to study the chemical interaction between the binder and the Al alloy. After making feedstock filaments, tensile tests, scanning electron microscopy (SEM), and fused filament fabrication (FFF) printing were done. The results showed that although the PP printability was acceptable, the best mechanical properties and printed quality can be achieved by PPMA. TGA test showed that all binder systems in the feedstocks could be removed completely around 500 °C. From FTIR, the possibility of chemical reactions between Al alloy particles and maleic anhydride groups on the grafted PP backbone could explain the better dispersion of the mixture and higher mechanical properties. Tensile strength in PP samples was 3.4 MPa which was improved 1.8 times using PPMA as the backbone.

MAX phase, as a group of layered ternary carbides and nitrides exhibiting combined properties of metallic and ceramic materials, attracts increasing interest because they own exceptionally chemical, physical, electrical, thermal, and mechanical properties. In the present paper, a novel Ti3AlC2-based green part was manufactured by extrusion-based fused filament fabrication (FFF) and 3D printing technologies. The morphology, thermal/electrical conductivity, thermal stability, electromagnetic interference (EMI) shielding effectiveness (SE), and mechanical properties of Ti3AlC2/binder with the volume ratio of 1:1 were investigated. The tensile and compressive strengths and elongation are measured to be 8.29 MPa and 18.20%, 44.90 MPa and 33.76%, respectively. The morphology of the filament reveals that Ti3AlC2 powders are well bonded by the thermoplastic binder. More importantly, the composite shows good thermal and electrical conductivities together with the excellent EMI shielding effectiveness, which is of great potential in the practical applications as conductor, heat dissipating, anti-static, and EMI shielding materials. The successful fabrication of Ti3AlC2-based composites via FFF-based 3D printing technology is beneficial to develop other MAX phase products with complex geometries and additional functionalities.

Metal injection moulding of miniaturized devices demands unique feedstock materials and mould designs with high dimensional accuracy. In this work, the influences of the powder size and powder content of 17–4 PH stainless steel feedstock and the influence of mould design on the successful production of micro-scaled structures were investigated. Ni mould inserts with high dimensional accuracy and texture sizes of 50–200 μm using a new microtexturing technique were manufactured. 17–4 PH stainless steel feedstocks with powder sizes (D90) of 10 and 22 μm and powder contents of 60 and 65 vol.-% were compounded. The rheological properties of the obtained feedstocks were characterized with a capillary rheometer to assess their flowability. The results showed that 10 μm sized particles caused a slight but not significant increase in the viscosity. The highest viscosity increase occurred when the powder content increased from 60 to 65 vol.-%. Feedstocks with the 10 μm powder particles ensured complete filling within microtextures for all mould variations. However, when using feedstocks with 22 μm particles, the filling capabilities of the 50 and 100 μm microtextures decreased with increasing powder content. The shape retention was better for those micropillars produced with mould inserts with 200 μm cavities than for the micropillars replicated with the inserts having cavities of 50 and 100 μm. The results indicated that the proposed mould insert preparation technique opens new possibilities for mass production using the μMIM process to create micro-scaled components using feedstocks without nanoparticles.

Material extrusion additive manufacturing can be used for producing metal specimens when combined with debinding and sintering, similar to metal injection moulding. A highly-filled polymeric filament containing 55 vol% of 17-4PH stainless steel powder was prepared and used to print dog-bone specimens. Printed specimens were debound and sintered to obtain metallic specimens. The tensile properties were investigated. The average Young’s modulus was determined to be 196 GPa, the average maximum stress was 696 MPa and the strain at break 4%. Adequate cohesion between layers during material extrusion additive manufacturing is crucial for improving the mechanical properties of sintered specimens.

Hardmetal and cermet bodies were printed by fused-filament fabrication (FFF) and composite-extrusion modelling (CEM) in an SDS (shaping – debinding – sintering) process. For FFF the filaments were prepared from hardmetal (WC-10Co) and cermet powder (Ti(C,N)-Co/Ni-based) and organic binder. The CEM feedstock consisted of WC-Co MIM powder. A 3D filament printer as well as a 3D printer working with a MIM granulate were employed to fabricate printed bodies by FFF and CEM, respectively. The solvent debinding process was performed in cyclohexane (FFF-printed bodies) or water (CEM-printed bodies). Thermal debinding of all parts was performed in a tube furnace up to a temperature of 800 °C. The pre-sintered parts were then subjected to vacuum sintering by application of conventional vacuum sintering profiles up to 1430 °C for hardmetals and up to 1480 °C for cermets. Dimensional and mass changes upon the various preparation steps as well as microstructure and porosity of the sintered bodies were investigated. While the microstructure is practically identical to that of conventionally prepared materials, some cavities were present from the printing process because of yet non-optimised printing strategy. By change of printing strategy the cavities could be minimised or even avoided. The study shows that with the applied 3D extrusion-printing techniques, hardmetal and cermet components with innovative geometries are accessible.

Material Extrusion Additive Manufacturing (MEAM) is mainly used for the production of polymeric components. Using feedstocks similar to those of powder injection moulding, MEAM of ceramic component...

Fabrication of titanium components is very cost intensive, partly due to the complex machining and limited recyclability of waste material. For electrochemical applications, the excellent corrosion resistance of pure titanium is of high importance, whereas medium mechanical strength of fabricated parts is sufficient for such a use case. For smaller parts, metal fused filament fabrication MF3 enables the fabrication of complex metallic structures densified during a final sintering step. Pure titanium can be processed to near net shape geometries for electrochemical applications if the parameters and the atmosphere during sintering are carefully monitored. Herein, the influence of thermal debinding and sintering parameters on the fabrication of high density pure titanium using MF3 is investigated. Particular focus is placed on enhancing sintered density while limiting impurity uptake to conserve the high chemical purity of the initial powder material. Relative densities of 95 are repeatedly reached inside the bulk of the samples. An oxygen content of 0.56 amp; 8201;wt as a result of vacuum processing induces the formation of the retained amp; 945; Ti phase 925 amp; 8201;HV0.2 inside the amp; 945; matrix 295 amp; 8201;HV0.2 . Fabricated parts exhibit high mechanical strength, albeit reduced elongation due to remaining pores, and, in terms of electrochemistry, enhanced stability toward anodic dissolution

Within this paper, we are dealing with a mixture of thermoplastic polymer that is filled with inorganic fillers at high concentrations up to 60 vol.%. A high number of particles in the compound can substantially change the rheological behaviour of the composite and can lead to problems during processing in the molten state. The rheological behaviour of highly filled materials is complex and influenced by many interrelated factors. In the present investigation, we considered four different spherical materials: steel, aluminium alloy, titanium alloy and glass. Particles with similar particle size distribution were mixed with a binder system at different filling grades (30&ndash, 60 vol.%). We showed that the rheological behaviour of highly filled materials is significantly dependent on the chemical interactions between the filler and matrix material. Moreover, it was shown that the changes of the particle shape and size during processing lead to unexpected rheological behaviour of composite materials as it was observed in the composites filled with glass beads that broke at high contents during processing.

The fused filament fabrication (FFF) of ceramics enables the additive manufacturing of components with complex geometries for many applications like tooling or prototyping. Nevertheless, due to the many factors involved in the process, it is difficult to separate the effect of the different parameters on the final properties of the FFF parts, which hinders the expansion of the technology. In this paper, the effect of the fill pattern used during FFF on the defects and the mechanical properties of zirconia components is evaluated. The zirconia-filled filaments were produced from scratch, characterized by different methods and used in the FFF of bending bars with infill orientations of 0&deg, &plusmn, 45&deg, and 90&deg, with respect to the longest dimension of the specimens. Three-point bending tests were conducted on the specimens with the side in contact with the build platform under tensile loads. Next, the defects were identified with cuts in different sections. During the shaping by FFF, pores appeared inside the extruded roads due to binder degradation and or moisture evaporation. The changes in the fill pattern resulted in different types of porosity and defects in the first layer, with the latter leading to earlier fracture of the components. Due to these variations, the specimens with the 0&deg, infill orientation had the lowest porosity and the highest bending strength, followed by the specimens with &plusmn, infill orientation and finally by those with 90&deg, infill orientation.

The adhesion of the polymer to ceramic nanoparticles is a key aspect in the manufacturing of ceramic parts by additive manufacturing and injection molding, due to poor separation results in separation during processing. The purpose of this research is to investigate, by means of molecular dynamics simulations and experimental methods, the role of improved interfacial interactions by acrylic acid grafting-high density polyethylene on the adhesion to zirconia nanoparticles and on the composite properties. The polymer grafting results in high adhesion to the nanoparticles, increases the nanoparticles dispersion and improves the viscoelastic and mechanical properties required for additive manufacturing and injection molding.

Material extrusion additive manufacturing (MEX) is a versatile technology for producing complex specimens of polymers, ceramics and metals. Highly-filled filaments composed of a binder system and a high-volume content of sinterable powders are needed to produce ceramic or metal parts. After shaping the parts via MEX, the binder is removed and the specimens are sintered to obtain a dense part of the sintered filler particles. In this article, the applicability of this additive manufacturing process to produce copper specimens is demonstrated. The particular emphasis is on investigating the production of lightweight specimens that retain mechanical properties without increasing their weight. The effect of infill grades and the cover presence on the debinding process and the flexural properties of the sintered parts was studied. It was observed that covers could provide the same flexural strength with a maximum weight reduction of approximately 23%. However, a cover on specimens with less than 100% infill significantly slows down the debinding process. The results demonstrate the applicability of MEX to produce lightweight copper specimens.

Technical ceramics are widely used for industrial and research applications, as well as for consumer goods. Today, the demand for complex geometries with diverse customization options and favorable production methods is increasing continuously. With fused filament fabrication (FFF), it is possible to produce large and complex components quickly with high material efficiency. In FFF, a continuous thermoplastic filament is melted in a heated nozzle and deposited below. The computer-controlled print head is moved in order to build up the desired shape layer by layer. Investigations regarding printing of metals or ceramics are increasing more and more in research and industry. This study focuses on additive manufacturing (AM) with a multi-material approach to combine a metal (stainless steel) with a technical ceramic (zirconia: ZrO2). Combining these materials offers a broad variety of applications due to their different electrical and mechanical properties. The paper shows the main issues in preparation of the material and feedstock, device development, and printing of these composites.

Fused Filament Fabrication (FFF) is a material extrusion based additive manufacturing technique that enables the processing of thermoplastic filaments, which are selectively extruded and deposited in a layer-wise manner to create three-dimensional objects. Filaments of polymer-based compounds highly- filled with ceramic powders (ca. 40-60 vol.%), known as feedstocks, can be processed by means of FFF to shape ceramic parts. Such parts are then debound in order to remove the polymer from the feedstock. A highly porous structure is obtained, which is sintered at high temperatures to produce dense ceramic components. The use of highly- filled polymers constitutes a processing challenge, due to their high viscosity that complicates the fabrication by FFF. The material properties of compounds filled with zirconia (ca. 47 vol%) were optimized by the incorporation of an additional low viscosity component. It was observed that by adding the low viscosity component, the mechanical properties (flexibility, strength and stiffness) and feedstock viscosity are suitable for the production of filaments and the FFF process. Furthermore, the low viscosity component further promotes the defect-free removal of the major polymer fraction by leaching with a solvent.

Powder extrusion moulding (PEM) is a versatile and cost-effective technology for producing bi-dimensional shapes, (e.g. tubes and profiles) from metals, ceramics and cermets. PEM quality is affected by powder content; therefore, three highly-filled polymeric compounds containing 50, 55, 60 vol% tool steel powder were prepared and extruded to profiles. Extruded parts were debound in cyclohexane and sintered in forming gas (Ar + 5% H2) to obtain dense, sintered parts. The dimensional stability, the shrinkage and the hardness were measured. Minimum shrinkage and higher dimensional stability were obtained when the powder content was the highest (60 vol%). Specimens with 50 vol% powder had the highest hardness due to the initial higher binder content and resulting carbon content.

By using filaments comprising metal or ceramic powders and polymer binders, solid metal and ceramic parts can be created by combining low-cost fused filament fabrication (FFF) with debinding and sintering. In this work, we explored a fabrication route using a FFF filament filled with 316 L steel powder at 55 vol.-%. We investigated the printing, debinding and sintering parameters and optimized them with respect to the mechanical properties of the final part. Special focus was placed on debinding and sintering in order to obtain components of low residual porosity. Solvent debinding of the printed green bodies created an internal network of interconnected pores and was followed by thermal debinding. Thermal debinding allowed for complete removal of the remaining binder and produced mechanically stable brown parts. Sintering at 1360 °C provided densification of the parts and generated nearly isotropic linear shrinkage of about 20%. Using optimized parameters, it was possible to fabricate 316 L steel components with a density greater than 95% via the material extrusion additive manufacturing, debinding and sintering route, with achievable deflections in a 3-point bending test similar to rolled sheet material, albeit at lower strength.

Fused Filament Fabrication (FFF) could replace injection molding as the shaping step in a process similar to powder injection molding (PIM). Herein after shaping by using a highly-filled polymer the part is debound and sintered to obtain a solid part of metal or ceramic. New feedstock materials have been developed that can be printed using conventional FFF equipment. And after debinding and sintering stainless steel parts can be obtained. However, there are many parameters that can affect the performance of the FFF feedstock materials. One important parameter is the particle size distribution of the filler particles. In this paper, feedstocks containing 316L steel powder with different particle size distributions were characterized in terms of viscosity and mechanical properties, and tested regarding the printability using a conventional FFF machine. It has been observed that the particle size significantly affects the properties of feedstock materials and thus their ability to be printed.

The adhesion tendency of the polymers polyoxymethylene, polyamide 6.6 and polyether ether ketone against hard coatings to protect molds in polymer processing was evaluated by a combination of tribological tests, investigations of wear tracks and measurements of the coatings' surface energies. It was found that a low surface roughness and a low surface energy of the coating are beneficial to reduce friction and adhesion tendency. Among the coating materials investigated, CrN seems to be the most promising candidate for the protection of molds for polymer processing.

Powder injection moulding (PIM) is a multi-stage process to manufacture metallic or ceramic complex, functional parts in large quantities and with high material requirements. The flow in PIM filling process is a complicated non-isothermal problem with viscoelasticity effects and instabilities. The exact description of the whole process of the flow is very difficult. The existence of a yield stress on PIM-feedstock depends on particle interactions within the polymer matrix. Further factors, like powder loading and dispersion during the measurements, are influencing the rheological characterisation of PIM-feedstocks. Additionally, inertial and gravitational effects can have an influence for systems with a very low viscous matrix. Quantifying yield stress, however, must be done carefully because the value obtained depends on the analytical technique used. Knowing the flow behaviour of PIM-feedstock is necessary for successful filling simulation of PIM. In this context, the yield behaviour of a stainless stee...

Injection molding is the most important process to produce plastic parts. Because of increasing complexity of the plastic parts and the aim to reach zero-defect production it is a must to control the dynamic injection molding process. Therefore information from the inside of the mold, measured with sensors, is necessary. State of the art is to implement wired mold cavity pressure sensors as well as wired cavity temperature sensors. This article presents a novel wireless measurement setup which uses structure borne sound as transport medium. The sound is generated by an acoustic actor which is activated by the passing flow front at certain predetermined positions in the cavity (or cavities). Beside the mechanical setup of the sensor proof of concept measurements with a prototype setup are shown in this article. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Additive manufacturing (AM) is the fabrication of real three-dimensional objects from metals, ceramics, or plastics by adding material, usually as layers. There are several variants of AM; among them material extrusion (ME) is one of the most versatile and widely used. In MEAM, molten or viscous materials are pushed through an orifice and are selectively deposited as strands to form stacked layers and subsequently a three-dimensional object. The commonly used materials for MEAM are thermoplastic polymers and particulate composites; however, recently innovative formulations of highly-filled polymers (HP) with metals or ceramics have also been made available. MEAM with HP is an indirect process, which uses sacrificial polymeric binders to shape metallic and ceramic components. After removing the binder, the powder particles are fused together in a conventional sintering step. In this review the different types of MEAM techniques and relevant industrial approaches for the fabrication of metallic and ceramic components are described. The composition of certain HP binder systems and powders are presented; the methods of compounding and filament making HP are explained; the stages of shaping, debinding, and sintering are discussed; and finally a comparison of the parts produced via MEAM-HP with those produced via other manufacturing techniques is presented.

Wireless sensing technology for injection molding is of increasing interest in literature. Recently, a purely mechanical in-mold sensor for melt front detection was introduced. The sensor system is based on building resonant structures into the mold which are excited by the passing melt front generating structure-borne sound, from which the melt front position is derived. A big advantage of this system is the possibility to implement a plurality of resonant structures while just having one receiver. One important aspect is the need to separate and assign the recorded impinging sounds. A novel algebraic approach was introduced separating the resonant structures by reference to their oscillatory behavior. In this article, measurement results for over 450 injection molding cycles are given proving functionality of the separation process. In addition, it is shown that the melt front detection is reliable and robust when comparing it with results obtained by cavity temperature sensors. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40346.

Surfaces of technical parts are getting more and more attention in terms of functionalization. By modification, additional functionality is given to the part, e.g. self-cleaning effect or antireflection behavior. Nowadays mainly flat surfaces are structured which is a consequence of the available production methods. However, the demand of micro structured free form surfaces is increasing, enabling novel products. A major problem in the mass production (e.g. injection molding) of structured freeform surfaces is to demold these structures without ripping or deforming them due to occurring undercuts. Recently a novel concept was developed which overcomes this limitation. A nickel substrate containing a structure composed of lines orientated in two different directions, one orientated in melt flow direction, the other one perpendicular to that, but both with a cross-section of approximately 45 μm × 55 μm (w × h) was used as a premaster to cast a flexible master. This master made of poly(dimethylsiloxane) (PDMS) was mounted on a bending edge in an injection mold cavity. Within this paper the influence of process parameters on the replication grade of the structure lines depending on the structure orientation was evaluated, varying the holding pressure, melt and mold temperature using statistical design of experiment methods. The replication grade was evaluated by characterizing the shape of the structure lines along the entire process chain, using an infinite focus system. The results show, that the melt temperature has the biggest influence on the dimensions of the structures, the mold temperature only a slight one.

Background —Arterial hypertension is a major risk factor for cardiovascular damage. The results of several studies suggest that target organ damage is greater in hypertensive persons with high blood pressure variability. Methods and Results —During 3.3 years of follow-up, we studied the relationship between circadian blood pressure changes and the progression of early carotid atherosclerosis in 286 patients aged >55 years. Blood pressure patterns were evaluated with a long-term blood pressure monitor, and the extent of atherosclerosis was measured as the intima-media wall thickness (IMT) of the common carotid artery. Patients were subdivided according to blood pressure variability. The progression of IMT was significantly greater in the patients with increased systolic blood pressure variability (0.11 mm/y [95% CI 0.09 to 0.14] versus 0.05 mm/y [0.03 to 0.08]; P 15 mm Hg) is associated with an increased relative risk of the development of early atherosclerosis (3.9 [1.4 to 11.1]; P P Conclusions —The daytime systolic blood pressure variability is a strong predictor of early carotid atherosclerosis progression and is useful to define the risk-benefit ratio of therapeutic approaches.

In this paper, the influencing parameters of a novel purely mechanical wireless in-mould injection moulding sensor were investigated. The sensor is capable of detecting the melt front at predefined locations inside the mould. The sensor comprises a movable pin which acts as the sensor element generating structure-borne sound triggered by the passing melt front. Due to the sensor design, melt pressure is the driving force. For pressure level measurement during pin movement a pressure transducer located at the same position as the movable pin. By deriving a mathematical model for the mechanical movement, dominant process parameters could be investigated towards their impact on the melt front detection characteristic. It was found that the sensor is not affected by the investigated parameters enabling it for reliable melt front detection. In addition, it could be proved that the novel sensor is in comparable range to conventional melt front detection sensors., {"references":["","K. K. 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Wireless devices are broadly adopted to the digital home environment, not least through integration of radios to Consumer Electronics (CEs) like TV screens or portable multimedia equipment. Accompanied by growth in wireless devices, demand on data rate increases, imposing new challenges on Medium Access Control (MAC) to improve channel access efficiency. Ultra Wideband (UWB) ECMA-368 offers very high data rate for short range communication. Two MAC protocols are standardized, the random based Prioritized Contention Access (PCA) and the Distributed Reservation Protocol (DRP), which is known to gain efficient channel access without data frame collision even in densely populated wireless network scenarios. Radio frequency signals propagated in the wireless channel are distorted and attenuated from obstacles. Particularly in home environments furniture and walls lead to not completely meshed network scenarios, thus raising the impact from hidden and exposed nodes on system capacity. The achievable throughput from gaining channel access concerning DRP channel access is not affected in presence of hidden nodes, whilst exposed nodes in wireless network scenarios lower system capacity. This paper presents an improvement to DRP, called DRPNext, to mitigate exposed nodes impact on system capacity and shows system capacity gain by more than 30% in benefit from reduced channel reuse distance in home environments.

The viscosity of feedstock materials is directly related to its processability during injection molding; therefore, being able to predict the viscosity of feedstock materials based on the individual properties of their components can greatly facilitate the formulation of these materials to tailor properties to improve their processability. Many empirical and semi-empirical models are available in the literature that can be used to predict the viscosity of polymeric blends and concentrated suspensions as a function of their formulation; these models can partly be used also for metal injection molding binders and feedstock materials. Among all available models, we made a narrow selection and used only simple models that do not require knowledge of molecular weight or density and have parameters with physical background. In this paper, we investigated the applicability of several of these models for two types of feedstock materials each one with different binder composition and powder loading. For each material, an optimal model was found, but each model was different; therefore, there is not a universal model that fits both materials investigated, which puts under question the underlying physical meaning of these models.

In this work, a model is presented, which is the basis of a quality control concept for the injection molding process. Contrary to statistical methods, this model uses physical dependencies of two quality parameters on four influencing parameters. The influences of holding pressure, holding time, melt temperature, and mold temperature on part mass and dimensions are described based on the fundamental material behavior such as pvT-data or energy equation. Furthermore, the influence of viscosity changes is indirectly taken into account using the injection work. Assuming only small deviations of the influencing parameters around an optimized operating point, the four parameters are treated as being independent from each other. With this assumption, a product ansatz was chosen with different functions for each influencing factor. Applying basic algebra, the starting equation was transformed into a form that describes either the change in part mass or characteristic part dimensions as a function of the influencing factors. The final equation for the part mass contains six model parameters, whereas nine model parameters are necessary for the equation for the part length. To obtain those model parameters some systematic experiments are required. Once the parameters are known, the model is able to calculate the change of the target values when the influencing factors vary around the operating point. The model was tested experimentally with focus on dimensions using a plastic cover made of an acrylonitrile butadiene styrene (ABS) grade. For the investigated part geometry and material grade, the process behavior was described well by the model. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

In this study, we analyzed the relationship between serum C-reactive protein (CRP) and the intima to media thickness (IMT) of the common carotid artery in 411 consecutive neurological inpatients (215 males, mean age 64.1 years). The CRP concentration was determined within 12 h and patients were subdivided according to the CRP level. Patients with an elevated CRP (n = 149) showed a significantly larger IMT [1.05 mm (95% confidence interval (CI) 1.02–1.09) vs. 0.92 mm (95% CI 0.89–0.94)]. Multivariate linear regression analysis revealed that an elevated CRP level, age, pack-years of smoking, body mass index, incidence of diabetes mellitus and ischemic stroke were independently associated with an increased IMT (p < 0.05).

Background The occurrence of lacunar infarction is closely related to arterial hypertension. However, there is only limited and partly controversial knowledge regarding the possible pathogenetic role of circadian blood pressure changes. Objective To evaluate the relationship between circadian blood pressure rhythm, occurrence, and extent of lacunar infarction. Methods We analyzed circadian blood pressure patterns, other cardiovascular risk factors, and occurrence of lacunar infarction in 118 hospitalized patients older than 55 years. Noninvasive 24-hour blood pressure measurements and magnetic resonance or computed tomographic brain imaging were performed in 61 patients with lacunar infarction and in 57 control patients. Daytime blood pressure variability was defined as the within-subject SD of all systolic and diastolic blood pressure readings during the daytime measurement period. Circadian blood pressure variation was defined as the average percentage change of nighttime blood pressure values compared with the daytime blood pressure values. Results Patients with lacunar infarction were significantly older and showed more often a history of arterial hypertension, elevated average daytime blood pressure values, an increased systolic daytime blood pressure variability, and a reduced circadian blood pressure variation due to an increased incidence of a pathologic nighttime blood pressure increase. No significant correlation was found between these parameters and the number of lacunae. A logistic regression analysis revealed that a reduced systolic circadian blood pressure variation, age, systolic average daytime blood pressure, and a history of arterial hypertension were best correlated with the occurrence of lacunar infarction. Conclusion Reduced nighttime decline in systolic blood pressure may be an important risk factor for the development of lacunar infarction in addition to the absolute level of blood pressure and age.

An economical alternative for the production of steel parts via additive manufacturing is to combine Fused Filament Fabrication (FFF) with debinding and sintering in a process referred as Shaping, Debinding and Sintering (SDS). In this paper, the SDS process for two types of feedstock materials containing two types steel alloys is described: from feedstock compounding to sintering. It was found that using the same binder system is possible to obtained sintered parts shaped by FFF with these two types of steel alloys (316L, 17-4PH).