ALISS: Advanced Linear Scheduling System

The line of balance (LOB) method is not widely used in the construction industry even though it has distinct advantages in repetitive construction projects. Attempts were made in the past to develop LOB systems but no system has met with universal acceptance because of a multitude of problems. As a response, a tool named ALISS was developed that solves most of the problems associated with LOB applications. ALISS is an acronym for Advanced Linear Scheduling System and makes use of a model that utilises the tools of information technology to the fullest extent. This is accomplished by creating a system that has a standalone and a web‐based version. ALISS is programmed using Visual Basic and Visual Basic Script languages. It utilises MS Access and SQL server as a data repository. The resulting Advanced Linear Scheduling System not only accommodates all LOB requirements but also provides the latest technological developments as an embedded tool.     

Compartmentalized Jet Polymerization as a High‐Resolution Process to Continuously Produce Anisometric Microgel Rods with Adjustable Size and Stiffness

In the past decade, anisometric rod‐shaped microgels have attracted growing interest in the materials‐design and tissue‐engineering communities. Rod‐shaped microgels exhibit outstanding potential as versatile building blocks for 3D hydrogels, where they introduce macroscopic anisometry, porosity, or functionality for structural guidance in biomaterials. Various fabrication methods have been established to produce such shape‐controlled elements. However, continuous high‐throughput production of rod‐shaped microgels with simultaneous control over stiffness, size, and aspect ratio still presents a major challenge. A novel microfluidic setup is presented for the continuous production of rod‐shaped microgels from microfluidic plug flow and jets. This system overcomes the current limitations of established production methods for rod‐shaped microgels. Here, an on‐chip gelation setup enables fabrication of soft microgel rods with high aspect ratios, tunable stiffness, and diameters significantly smaller than the channel diameter. This is realized by exposing jets of a microgel precursor to a high intensity light source, operated at specific pulse sequences and frequencies to induce ultra‐fast photopolymerization, while a change in flow rates or pulse duration enables variation of the aspect ratio. The microgels can assemble into 3D structures and function as support for cell culture and tissue engineering.     

Plural: A decentralized business process modeling method

Top-down and centralized approaches prevail in the design and improvement of business processes. However, centralized structures pose difficulties for organizations in adapting to a rapidly changing business environment. Here we present the Plural method which can be used to guide organizations in performing process modeling in a decentralized way. Instead of a centralized group of people understanding, modeling and improving processes, our method allows individuals to model and improve their own processes to help in fulfilling their roles in the organization. An individual model depicts a set of activities performed by a role, which together result in a cohesive service within the organization. These individual models are then integrated as necessary to show the way the organization works. We applied the Plural method in a case study of a small-size software organization. We describe the method and its underlying principles and then discuss the findings of our case study, lessons learned, and limitations. The study thus provided evidence of Plural's utility and showed how an organization might exploit its strengths.     

Complexity issues in robust stability of linear delay-differential systems

In this paper the following stability problems concerning linear delay-differential systems are shown to beN P-hard: (i) asymptotic stability independent of delay, and (ii) robust asymptotic stability, when each delay is known to lie in an interval. The main results are based on theN P-hardness of complex bilinear programming over the polydisk ⁿ which also shows that the purely complexμ computation, analysis/synthesis problems areN P-hard even if there are no repeated blocks. Another side result of the paper is that checking robust nonsingularity, robust Hurwitz stability, and robust Schur stability of a disk matrix areN P-hard problems. This work was supported by the Ohio State University and DISC (Dutch Institute of Systems and Control). This work was completed while the first author was at the Faculty of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.     

Determination of discontinuities in marble blocks via a nondestructive ultrasonic technique

Miners working in the marble industry have always been interested in identifying structural weaknesses in marble blocks before they are transported to marble processing plants.To achieve this difficult task,several simple methods have been developed among miners but observation-based methods do not consistently provide satisfactory results.A nondestructive method developed for testing concrete could be used for this purpose.In this study,this simple method based on differences in ultrasonic wave propagation...     

A novel method for pulmonary embolism detection in CTA images

In this paper, we propose a new computer-aided detection (CAD) – based method to detect pulmonary embolism (PE) in computed tomography angiography images (CTAI). Since lung vessel segmentation is the main objective to provide high sensitivity in PE detection, this method performs accurate lung vessel segmentation. To concatenate clogged vessels due to PEs, the starting region of PEs and some reference points (RPs) are determined. These RPs are detected according to the fixed anatomical structures. After lung vessel tree is segmented, the region, intensity, and size of PEs are used to distinguish them. We used the data sets that have heart disease or abnormal tissues because of lung disease except PE in this work. According to the results, 428 of 450 PEs, labeled by the radiologists from 33 patients, have been detected. The sensitivity of the developed system is 95.1% at 14.4 false positive per data set (FP/ds). With this performance, the proposed CAD system is found quite useful to use as a second reader by the radiologists.     

Effects of ceramic-based CrN,TiN, and AlCrN interlayers on wear and friction behaviors of AlTiSiN+TiSiN PVD coatings

In this study, the wear and friction behavior of cathodic arc physical vapor deposited AlTiSiN+TiSiN coatings on H13 tool steels were investigated by using CrN, TiN and AlCrN interlayers with tribometer tests both under unlubricated and boundary lubricated conditions. 6 mm alumina balls were used as counter surfaces to test ceramic hard coatings. Surface coatings were characterized through nanoindentation, scanning electron microscopy coupled with an energy-dispersive X-ray spectrometer (SEM/EDXS), optical profilometry, and atomic force microscopy (AFM) techniques. The results showed that especially AlTiSiN+TiSiN coating with TiN interlayer resulted in a much more enhanced tribological performance of the tool steels at both unlubricated and the boundary lubricated conditions even at elevated contact pressures.     

Comprehensive characterization of PVDF-TrFE thin films for microelectromechanical system applications

This paper presents a comprehensive characterization of a polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) thin film with 75/25 molar ratio for piezoelectric MEMS applications. PVDF-TrFE film was deposited on a silicon substrate using spin coating, and electrodes were formed using sputtering. Dielectric constant and dielectric loss factor were measured at different frequencies. Frequency and temperature dependence of the ferroelectric response was examined to investigate required poling conditions and maximum operating temperature. The lower limit for the coercive field was measured as 55 V/μm at room temperature. Coercive field decreased with temperature with a slope of ?0.1 V/μm K, and ferroelectric to paraelectric transition occurred between 100? and 108?°C. Piezoelectric displacement measurements were performed using an atomic force microscope based method. Average value of the effective piezoelectric d₃₃ coefficient was measured as ?23.9 pm/V. No degradation was observed in this value after 2?×?10⁵ unipolar excitation cycles. On the other hand, significant fatigue was observed in the piezoelectric response due to polarization switching; 1.8?×?10⁵ cycles caused an average reduction of 33% in the effective d₃₃. Presented data corroborates with the previous studies in the literature and can be used in the design of PVDF-TrFE based MEMS devices utilizing its dielectric, ferroelectric, and piezoelectric properties.     

Biologically Inspired Scaffolds for Heart Valve Tissue Engineering via Melt Electrowriting

Heart valves are characterized to be highly flexible yet tough, and exhibit complex deformation characteristics such as nonlinearity, anisotropy, and viscoelasticity, which are, at best, only partially recapitulated in scaffolds for heart valve tissue engineering (HVTE). These biomechanical features are dictated by the structural properties and microarchitecture of the major tissue constituents, in particular collagen fibers. In this study, the unique capabilities of melt electrowriting (MEW) are exploited to create functional scaffolds with highly controlled fibrous microarchitectures mimicking the wavy nature of the collagen fibers and their load‐dependent recruitment. Scaffolds with precisely‐defined serpentine architectures reproduce the J‐shaped strain stiffening, anisotropic and viscoelastic behavior of native heart valve leaflets, as demonstrated by quasistatic and dynamic mechanical characterization. They also support the growth of human vascular smooth muscle cells seeded both directly or encapsulated in fibrin, and promote the deposition of valvular extracellular matrix components. Finally, proof‐of‐principle MEW trileaflet valves display excellent acute hydrodynamic performance under aortic physiological conditions in a custom‐made flow loop. The convergence of MEW and a biomimetic design approach enables a new paradigm for the manufacturing of scaffolds with highly controlled microarchitectures, biocompatibility, and stringent nonlinear and anisotropic mechanical properties required for HVTE.