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The purpose of this paper is establishing a general mathematical model and theoretical design rules for 3D printing of biomaterials. Additive manufacturing of biomaterials provides many opportunities for fabrication of complex tissue structures, which are difficult to fabricate by traditional manufacturing methods. Related problems and research tasks are raised by the study on biomaterials’ 3D printing. Most researchers are interested in the materials studies; however, the corresponded additive manufacturing machine is facing some technical problems in printing user-prepared biomaterials. New biomaterials have uncertainty in physical properties, such as viscosity and surface tension coefficient. Therefore, the 3D printing process requires lots of trials to achieve proper printing parameters, such as printing layer thickness, maximum printing line distance and printing nozzle’s feeding speed; otherwise, the desired computer-aided design (CAD) file will not be printed successfully in 3D printing.

Most additive manufacturing machine for user-prepared bio-material use pneumatic valve dispensers or extruder as printing nozzle, because the air pressure activated valve can print many different materials, which have a wide range of viscosity. We studied the structure inside the pneumatic valve dispenser in our 3D heterogeneous printing machine, and established mathematical models for 3D printing CAD structure and fluid behaviors inside the dispenser during printing process.

Based on theoretical modeling, we found that the bio-material’s viscosity, surface tension coefficient and pneumatic valve dispenser’s dispensing step time will affect the final structure directly. We verified our mathematical model by printing of two kinds of self-prepared biomaterials, and the results supported our modeling and theoretical calculation.

For a certain kinds of biomaterials, the mathematical model and design rules will have unique solutions to the functions and equations. Therefore, each biomaterial’s physical data should be collected and input to the model for specified solutions. However, for each user-made 3D printing machine, the core programming code can be modified to adjust the parameters, which follows our mathematical model and the related CAD design rules.

This study will provide a universal mathematical method to set up design rules for new user-prepared biomaterials in 3D printing of a CAD structure.

One of the primary problems in the production of cement testing cubes is inconsistency in quality due to skill differences between operators and low repeatability in human performance of identical operations. To eliminate this problem and to enhance productivity, a state‐of‐the‐art robot workcell system, which utilized a multitasking control strategy and tool changer and sensor technology to automatically produce cement testing cubes, was designed and integrated. A comparative analysis of compressive strength values of specimens made by human operators and robots indicated that the specimens made by the robot workcell system had lower variation than the human made ones. This study not only demonstrates that robot workcells are flexible and robust enough to be used in cement testing cube production, but also suggests that revision of American Society of Testing Methods (ASTM) procedures to facilitate implementation of high technology in the materials testing process should be considered.

Claims that, although the use of adhesives in automated assembly is common, the use of structural adhesives is not so. Indeed, the use of structural adhesives can be termed a “new technology”. Offers advice on their use and concludes that the benefits outweigh the threat of failure.

This paper aims to present a novel rapid prototyping (RP) fabrication methods and preliminary characterization for chitosan scaffolds.

A desktop rapid prototyping robot dispensing (RPBOD) system has been developed to fabricate scaffolds for tissue engineering (TE) applications. The system is a computer‐controlled four‐axis machine with a multiple‐dispenser head. Neutralization of the acetic acid by the sodium hydroxide results in a precipitate to form a gel‐like chitosan strand. The scaffold properties were characterized by scanning electron microscopy, porosity calculation and compression test. An example of fabrication of a freeform hydrogel scaffold is demonstrated. The required geometric data for the freeform scaffold were obtained from CT‐scan images and the dispensing path control data were converted form its volume model. The applications of the scaffolds are discussed based on its potential for TE.

It is shown that the RPBOD system can be interfaced with imaging techniques and computational modeling to produce scaffolds which can be customized in overall size and shape allowing tissue‐engineered grafts to be tailored to specific applications or even for individual patients.

Important challenges for further research are the incorporation of growth factors, as well as cell seeding into the 3D dispensing plotting materials. Improvements regarding the mechanical properties of the scaffolds are also necessary.

One of the important aspects of TE is the design scaffolds. For customized TE, it is essential to be able to fabricate 3D scaffolds of various geometric shapes, in order to repair tissue defects. RP or solid free‐form fabrication techniques hold great promise for designing 3D customized scaffolds; yet traditional cell‐seeding techniques may not provide enough cell mass for larger constructs. This paper presents a novel attempt to fabricate 3D scaffolds, using hydrogels which in the future can be combined with cells.

Standardized systems for feeding, gripping, and joining are needed to realize the potential of microsystem and nano‐system technology. This paper describes many several systems that are operating in this area and the applications for the new technology and the parts that can currently be manufactured. These include miniature pneumatic valves, matchstick sized motors and fluidic pumps.

IT would be quite refreshing to have an open breeze blowing through the ranks of work study technicians these days. Away with the ponderous exponents of the mystic art and, instead, finding the experts telling the workers how easy work study really is if only you sit down and think about it. It has, of course, many difficult and complex aspects but let us not confuse the issue, since these aspects can be left to the professionals' — after all that is what they get paid for — sorting out and providing solutions to the problems!

Criminal proceedings can only follow the commission of an offence, made so by statute. If an act is not unlawful, it matters little with what motives a person commits it or the consequences; he is outside the law, i.e. criminal law; civil law might have a remedy, but criminal law does not. Even when a criminal offence is committed, it may contain ingredients without which, what would otherwise be a punishable act, becomes guiltless. Most qualifications to guilt are of longstanding, used by parliamentary draftsmen in a wide range of statutes and have acquired reasonably precise judicial meaning. Most relate to intention—wilfully, intentionally, knowingly—and in a few, judicial extension of the popular meaning and usage of the term has occurred to prevent an innocent stance being simulated by a guilty party. “Knowledge” is such an example. The term has been deliberately widened to cover persons who “shut their eyes” to an offence; where a person deliberately refrains from making enquiries, the results of which he would not care to know, this amounts to having such knowledge— constructive knowledge.

SINCE ancient man first slapped fat on an axle, thereby reducing friction, not a lot has changed. The wastage rate of the fat lubrication has been reduced; lubricants themselves have improved substantially over animal fats, but the basic possibly oversimplified, method outlined above remains the same.

NOT perhaps the most vintage of Farnboroughs from the point of view of new aircraft and new technology, but undoubtedly one of the most successful in relation to the business done. Some fifteen major orders worth over £32½ million were announced, bringing the total order book for the industry this year to more than £782 million already. This exceeds by a handsome margin the new business won by the industry in any nine‐month period in the past, and it is expected that by the end of the year orders worth well over £800 million will have been received. Highlights of the new British hardware on show were the Hawker Siddeley Nimrod and production Harriers on the military side; the B.A.C. One‐Eleven 500, the Handley Page Jetstream, the Garrett‐engined Short Skyvan, and the Beagle Pups showed the resurgence of the industry's civil interests. The number of foreign aircraft that appeared, sponsored in the main by Rolls‐Royce, bore witness to the strength of Britain's aero engine and aircraft equipment industry, and further evidence of this was found in the exhibition proper with many examples of major items of equipment having been adopted for overseas markets. The overall impression at Farnborough was a new‐found confidence in the future of the industry exemplified by a more aggressive and effective export sales policy that has already proved our ability to deliver the goods. It is not possible to cover all the exhibits shown at Farnborough, but the report following describes many of the interesting items.