ASME Conference Presenter Attendance Policy and Archival Proceedings

2017;():V004T00A001. doi:10.1115/MSEC2017-NS4.

This online compilation of papers from the ASME 2017 12th International Manufacturing Science and Engineering Conference (MSEC2017) represents the archival version of the Conference Proceedings. According to ASME’s conference presenter attendance policy, if a paper is not presented at the Conference by an author of the paper, the paper will not be published in the official archival Proceedings, which are registered with the Library of Congress and are submitted for abstracting and indexing. The paper also will not be published in The ASME Digital Collection and may not be cited as a published paper.

Commentary by Dr. Valentin Fuster

Bio and Sustainable Manufacturing: Advances in Analysis, Design, and Manufacturing of Biomedical Devices

2017;():V004T05A001. doi:10.1115/MSEC2017-2619.

This paper describes design and development of novel lubricant free transmission system for manual bone drilling machine. In order to design the transmission system, applied forces and torques on the gears has to be achieved. In this regard, bone drilling forces and torques were detected, preforming experimental tests of the drilling operation by CNC milling machine. At this point, various drill diameters and machining parameters were considered. After achieving the bone drilling forces, they were utilized for gears design process. The design process including gear geometry, material and detailed design analysis were done according to German norm VDI 2736 - Part 3. In this context, the mating worm gears materials were selected out of stainless steel 316 and Polyether Ether Ketone (PEEK), which can reduce weight, noise, moment of inertia, and necessity of lubrication, etc. In order to evaluate the gears performance, numerically and experimentally were performed. The static stress and deflection of the PEEK gear tooth were investigated numerically by finite element analysis. According to the numerical results, each tooth force carrying capacity (until yield stress) were estimated until 302 N. Surface temperature and wear rate for two types of PEEK gears were examined, experimentally, while applying two resistance torque values, 0.75 and 0.5 Nm, to the manufactured transmission system. The selected torques were three and five times bigger than drilling torque values, enabling us to simulate the bone drilling operation considering unexpected loaded in the extreme case, misuse, emergence situation, and degradation. The maximum temperatures of the tooth contour of the transmission system raised to 127 °C. According to the results, the maximum achieved PEEK gear life was 200 minutes for the Natural PEEK polymer at the 0.5 Nm torque.

Commentary by Dr. Valentin Fuster
2017;():V004T05A002. doi:10.1115/MSEC2017-2778.

Microfluidic lab-on-a-chip (MLOC) technology is a promising approach for point-of-care (POC) diagnosis; low reagent consumption, high sensitivity and quick analysis time are the most prominent benefits. However, microfabrication of MLOCs utilizes specialized techniques and infrastructure, making conventional fabrication time consuming and difficult. While relatively inexpensive production techniques exist for POC diagnoses, such as replication of polymer-based (e.g., PDMS) microfluidic POC devices on lithographic molds, this approach has limitations including: further hydrophilic surface modifications of PDMS, inability to change lithographic mold Z dimensions, and slow prototyping. In contrast, stereo-lithographical (SLA) printing can integrate all of the necessary fabrication resources in one instrument, allowing highly versatile microfluidic devices to be made at low cost. In this paper, we report two microfabrication approaches of microfluidics utilizing (SLA) 3D printing technology: I) Direct SLA printing of channels and structures of a monolithic microfluidic POC device; II) Indirect fabrication, utilizing SLA 3D printed molds for PDMS based microfluidic device replication. Additionally, we discuss previous work providing a proof of concept of applications in POC diagnosis, using direct 3D printing fabrication (approach I). The robustness and simplicity of these protocols allow integrating 3D design and microfabrication with smartphone-based disease diagnosis as a stand-alone system, offering strong adaptability for establishing diagnostic capacity in resource-limited areas and low-income countries.

Commentary by Dr. Valentin Fuster
2017;():V004T05A003. doi:10.1115/MSEC2017-2814.

The goal of this paper is to develop a design methodology to create customized biomedical devices which can be fabricated through 3D printing technology. Due to the increasing demands of hand rehabilitation and prosthetic accessories, we focus on designing a pneumatically actuated soft gripper applicable on these issues. The gripper is composed of 3D printable soft material, which results in a safe interaction with human bodies due to inherently low modulus. Each gripper finger is designed to mimic the real-world movement of a human finger, where the complex physical finger locomotion is modelled as the continuous bending deformation of the soft gripper finger. Working as a compliant mechanism, the design process is performed to maximize the possible bending deformation. The topology optimization method is adopted to design the best performance gripper finger. The optimized gripper shows high consistence with human fingers because of the pseudo-joints. Sequentially, the designed gripper is directly fabricated through 3D printing technology and characterized with free travel trajectory tracking experiments.

Topics: Design , Grippers
Commentary by Dr. Valentin Fuster
2017;():V004T05A004. doi:10.1115/MSEC2017-2850.

This work investigates the compliance of a novel flexure hinge mechanism for tissue cutting. This hinge is to be used with ultrasonic axial vibration to induce transverse displacement. This transverse motion can aid in reducing tissue cutting force as well as possible target deflection by reducing the parallel tissue cutting force. The finite element method, FEM, is used to evaluate several flexural hinge designs to develop empirical equations for the compliance in the axial, transverse, and rotational directions. To generate appreciable transverse motion from an axially applied ultrasonic vibration an asymmetric flexural hinge is needed. In order to design an asymmetric complaint mechanism to fully take advantage of the transverse cutting motion the compliance with respect to geometry was explored. The ratio of thickness, length, and distance between the hinges were iterated while end loads were applied to derive the compliance equations. The empirical models are presented for each design study. It is shown that the rotational stiffness is the dominating factor of the stiffness matrix. It is also shown that the relationship between the rotational stiffness and the distance between hinges forms a piecewise equation. This is due to notch elements spaced close to each other can be modeled as a lumped element while notch elements spaced further apart need to be independently modeled.

Commentary by Dr. Valentin Fuster
2017;():V004T05A005. doi:10.1115/MSEC2017-2944.

Electrosurgical vessel joining is commonly performed in surgical procedures to maintain hemostasis. This process requires elevated temperature to denature the tissue and while compression is applied, the tissue can be joined together. The elevated temperature can cause thermal damages to the surrounding tissues. In order to minimize these damages, it is critical to understand how the tissue properties change and how that affects the thermal spread. This study used porcine aorta arterial tissue to investigate tissue thermal conductivity with variable thermal dose. Seven joining times (0, 0.5, 1, 1.5, 2, 4, and 6 seconds) were used to create different amounts of thermal dose. A hybrid method that uses both experimental measurement and inverse heat transfer analysis was conducted to determine the thermal conductivity of thin tissue samples. In general, the tissue thermal conductivity decreases when thermal dose increases. Accordingly, 36% decrease in tissue thermal conductivity was found when the thermal dose reaches the threshold for second-degree burn (with 2-second joining time). When thermal dose is beyond the threshold of third-degree burn, the tissue thermal conductivity does not decrease significantly. A regression model was also developed and can be used to predict tissue thermal conductivity based on the thermal dose.

Commentary by Dr. Valentin Fuster
2017;():V004T05A006. doi:10.1115/MSEC2017-2954.

The significant advance in the boosted fabrication speed and printing resolution of additive technology has considerably increased the capability of achieving product designs with high geometric complexity. The prefabrication computation has been increasingly important and is coming to be the bottleneck in the additive manufacturing process. In this paper, the authors devise an integrated computational framework by synthesizing the parametric level set-based topology optimization method with the DLP-based SLA process for intelligent design and additive manufacturing of not only single material structures but also multi-scale, multi-functional structures. The topology of the design is optimized with a new distance-regularized parametric level set method considering the prefabrication computation. offering the flexibility and robustness of the structural design that the conventional methods could not provide. The output of the framework is a set of mask images which can be directly used in the additive manufacturing process. The proposed approach seamlessly integrates the rational design and manufacturing to reduce the complexity of the computationally-expensive prefabrication process. Two test examples, including a freeform 3D cantilever beam and a multi-scale meta-structure, are utilized to demonstrate the performance of the proposed approach. Both the simulation and experimental results verified that the new rational design could significantly reduce the prefabrication computation cost without affecting the original design intent or sacrificing original functionality.

Commentary by Dr. Valentin Fuster
2017;():V004T05A007. doi:10.1115/MSEC2017-2962.

This paper develops a novel standing surface acoustic wave (SAW) device with three-pair of interdigital transducers (IDTs) to fabricate the patterned microstructure arrays with the assistance of ultraviolet (UV) polymerization. The working principle, structural design, and fabrication of the SAW device are presented. Then experimental setup was conducted to investigate the fabrication process and method of the patterned microstructure arrays on a thin liquid polymer surface. By adjusting the input wavelength and working voltage and selecting the pairs of IDTs, several types of patterned microstructure arrays, such as linear undulate and latticed undulate with different surface morphologies, could be fabricated. Results also demonstrated that the developed SAW device with the assistance of UV polymerization is an effective method to fabricate the patterned microstructure arrays, which may have great potential in the application of biomedical and microelectronic fields.

Commentary by Dr. Valentin Fuster
2017;():V004T05A008. doi:10.1115/MSEC2017-2989.

Electro-hydrodynamic Jetting or E-Jetting is a process in which a polymer, dissolved in a solvent and extruded through a needle onto a substrate. A potential difference is applied between the needle and the substrate to facilitate the homogeneous extrusion of the fiber. This process is used to fabricate two dimensional scaffolds with porous mesh surfaces which act as a template for cell growth. As cells are very minute and are required to attach to the surface of the scaffold, it is essential to for the scaffold to have an adequate pore size that allows for nutrient transfer while preventing the penetration of cells through the scaffold. The fiber dimensions of the scaffold may be modified by varying the diameter of the needle through which the fiber is extruded. The change in fiber diameter subsequently results in the change in the bulk mechanical characteristics of the scaffold. It also causes a change in the net porosity of the scaffold. This paper aims to study the effect of the needle diameter on the bulk mechanical properties of the scaffold such as Young’s modulus, Tensile strength and Breaking Strength as well as morphological properties (porosity and pore size) of the

Scaffolds are dependent on the cell type, as each type of cell has a different set of requirements depending on the functionality. Bone cells are smaller than soft tissue cells, hence a common scaffold design may not be suit either of the applications. Thus, a one size fits all approach is not suitable for the scaffold [9]. As seen in Figure 1, the Red Blood Cells are a fraction of the size of the fibroblasts and bone marrow stem cells [20–22]. Similarly, the stiffness of the cells is also different.

Electro Hydrodynamic Jetting (E-jetting) is a process that is used to fabricate such 2D scaffolds by extruding a polymer solution through a needle and forming a fiber by applying a scaffold. For this study, twelve scaffolds belonging to three study groups were synthesized using e-jetting. By studying the effect of needle diameter on scaffold morphology and strength, we aim to develop a co-relation between the scaffold parameters, which will ultimately help in the creation of a knowledge database. The purpose of creating this database is to choose a select needle for a selected biomedical application.

Topics: needles
Commentary by Dr. Valentin Fuster
2017;():V004T05A009. doi:10.1115/MSEC2017-2992.

An automated inflatable repositioning device was created in this study for use in the developmentally supportive care of premature neonates. Inflatable air cells were used to achieve the safe positioning of these patients. The system is comprised of two pumps, four valves and four inflatable air cells that safely and slowly direct the air flow into the desired air cells by means of an Arduino Uno and a multi-directional control switch in order to obtain safe and proper positioning. Range of motion testing was conducted and it was discovered that this system is successful in achieving a sufficient range of motion in order to safely position the manikin. A pressure sensor was also connected to the system to measure the amount of pressure in the air cells over time during inflation. From this testing, it was found that the system is successful in inflating the air cells in a slow and controlled manner. Additionally, four NICU nurses from the Kapi’olani Medical Center for Women and Children tested the device and a survey was conducted to obtain feedback about the performance of the system. Overall, the device created was found to be successful in achieving positions in four directions in a safe, slow and controlled manner by means of an easy to use system that has the potential to be integrated into current neonatal health care technology.

Commentary by Dr. Valentin Fuster
2017;():V004T05A010. doi:10.1115/MSEC2017-3000.

This study develops an experimental method to measure the needle deflection and prostate movement using an anatomically accurate prostate simulator with the electromagnetic tracking (EMT) system. Accurate needle insertion is crucial for prostate biopsy to acquire the tissue samples from cancer sites identified by magnetic resonance imaging. False negatives or inability to diagnose are the clinical challenges in the biopsy procedure. The main cause is that the needle tip missed the targeted cancer sites due to needle deflection and prostate movement. An anatomically accurate prostate simulator was developed to quantitatively and experimentally measure the deviation of needle tip from the ideal path and the movement of a target point in the prostate. The EMT system was utilized to simultaneously track the needle tip and target point positions in 3D space. Results show that the maximal needle deflection occurred at the first 60-mm insertion with 6.7 and 0.7 mm in and perpendicular to the needle insertion plane, respectively. The corresponding target point movements were 6.5 mm and 2.4 mm in and perpendicular to the needle insertion plane, respectively. Differences between multiple insertions through the same path have also been quantified. This method can be utilized to study clinical prostate biopsy techniques, evaluate the accuracy of needle devices, and train clinicians for accurate prostate needle biopsy.

Topics: Deflection , needles
Commentary by Dr. Valentin Fuster
2017;():V004T05A011. doi:10.1115/MSEC2017-3002.

Arteriovenous fistula is the joining of an artery to a vein to create vascular access for dialysis. The failure or maturation of fistula is affected by the vessel wall shear stress (WSS), which is difficult to measure in clinic. A computational fluid dynamics (CFD) model was built to estimate WSS of a patient-specific fistula model. To validate this model, a silicone phantom was manufactured and used to carry out a particle imaging velocimetry (PIV) experiment. The flow field from the PIV experiment shows a good agreement with the CFD model. From the CFD model, the highest WSS (40 Pa) happens near the anastomosis. WSS in the vein is larger than that in the artery. WSS on the outer venous wall is larger than that on the inner wall. The combined technique of additive manufacturing, silicone molding, and CFD is an effective tool to understand the maturation mechanism of a fistula.

Commentary by Dr. Valentin Fuster
2017;():V004T05A012. doi:10.1115/MSEC2017-3091.

Bipolar tissue welding is a material joining process where high frequency alternating current is applied to biological tissue in medical procedures such as wound closure and blood vessel sealing. The process is often performed with a set of laparoscopic forceps in a minimal invasive surgery to achieve less bleeding and shorter recovery time. However, problems such as tissue sticking, thermal damage, and joint failure often occur and need to be solved before the process can be reliably used in more surgical procedures. In this study, experiments were conducted to investigate dynamic behavior of the tissue welding process through electrical impedance measurements. Both scissor-type and parallel electrodes were used with various compression and power settings in the experiment. It was found that the electrical impedance of tissue was lower when parallel electrodes were used. It can be used to understand the results and dynamic behavior of the tissue welding process, including the size of heat affected zone, tissue sticking, and the compression force effect.

Commentary by Dr. Valentin Fuster

Bio and Sustainable Manufacturing: Advances in Biomanufacturing of Tissue-Engineered Scaffolds

2017;():V004T05A013. doi:10.1115/MSEC2017-2725.

In any three dimensional (3D) biofabrication process, assessing critical biological quality attributes of 3D constructs such as viable cell number, cell distribution and metabolic activity is critical to determine the suitability and success of the process. One major limitation in current state-of-the-art is the lack of appropriate methods to monitor these quality attributes in situ in a non-destructive, label-free manner. In this study, we investigate the feasibility of using dielectric impedance spectroscopy to address this gap. We first measured the relative permittivity of 3D alginate constructs with four different concentrations of encapsulated MG63 cells (1–6.5 million cells/mL) and found them to be statistically significantly different (p < 0.05). Within the tested range, the relationship between cell concentration and relative permittivity was noted to be linear (R2 = 0.986). Furthermore, we characterized the β-dispersion parameters for MG63-encapsulated in alginate (6.5 million cells/mL). These results demonstrate that dielectric impedance spectroscopy can be used to monitor critical quality attributes of cell-encapsulated 3D constructs. Owing to the measurement efficiency and non-destructive mode of testing, this method has tremendous potential as an in-process quality control tool for 3D biofabrication processes and the long-term monitoring of cell-encapsulated 3D constructs.

Commentary by Dr. Valentin Fuster
2017;():V004T05A014. doi:10.1115/MSEC2017-2742.

A regular pattern called crimp is an essential morphological feature of collagen fibers in native tendon. In this study, the direct crimp writing (DCW) and zig-zag pattern writing (ZPW) were developed based on electrohydrodynamic jet printing (E-jetting) process to fabricate the crimped fibers. For the DCW process, the fibers were deposited with the linear movement of stage, and the crimps (crimp angle: ∼ 46°; crimp length: ∼630 μm; fiber diameter: ∼100 μm) were formed from the spinning of fibers. For the ZPW process, the fibers was printed via the zig-zag moving path, and the effects of a vital process parameter (i.e. dwell time) on the fiber characteristics were investigated to obtain controllable and regular crimped fibers. The result of mechanical testing showed that the ZPW fibers exhibited the “toe” and linear regions with different Young’s modulus (4 ± 1 MPa and 23 ± 4 MPa, respectively), while DCW fibers were found only with linear region. Compared with DCW process, the ZPW process was able to fabricate crimped fibers in a more controllable pathway. The human tenocytes were also seeded on the ZPW fibers to investigate the cellular alignment. This study suggested that ZPW process was capable of printing crimped fibers which mimicked the fiber profile in human tendon, and has the potential in scaffold fabrication for tendon tissue engineering.

Commentary by Dr. Valentin Fuster
2017;():V004T05A015. doi:10.1115/MSEC2017-2853.

Bioprinted tissue constructs are enabled by microextrusion-based co-printing of cells and hydrogel materials. In this paper, a gelatin-alginate hydrogel material formulation is implemented as the bio-ink towards a 3D cell-laden tissue construct. However, of fundamental importance during the printing process is the interplay between the various parameters that yield the final cell distribution and cell density at different dimensional scales. To investigate these effects, this study advances a multidimensional analytical framework to determine the spatial variations and temporal evolution of cell distribution and cell density within a bioprinted cell-laden construct. In the one dimensional (1D) analysis, the cell distribution and cross-sectional shape for a single printed fiber are observed to be dependent on the process temperature and material concentration parameters. This is illustrated by the reliable fabrication and image line profile analysis of the fiber prints. Round fiber prints with a measured width of 809.5±52.3 μm maintain dispersive cells with a degree of dispersion (Dd) at 96.8 % that can be achieved at high relative material viscosities under low temperature conditions (21 °C) or high material concentrations (10 % w/v gelatin). On the other hand, flat fiber prints with a measured width of 1102.2±63.6 μm coalesce cells towards the fiber midline with Dd = 76.3% that can be fabricated at low relative material viscosities under high temperature (24 °C) or low material concentrations (7.5 % w/v gelatin). In the 2D analysis, a printed grid structure yields differential cell distribution whereby differences in localized cell densities are observed between the strut and cross regions within the printed structure. At low relative viscosities, cells aggregate at the cross regions where two overlapping filaments fuse together, yielding a cell density ratio of 2.06±0.44 between the cross region and strut region. However, at high relative viscosities, the cell density ratio decreases to 0.96±0.03. In the 3D analysis, the cell density attributed to the different layers is studied as a function of printing time elapsed from the initial bio-ink formulation. Due to identifiable gravity and extrusion process-induced effects, the cell distribution within the original bio-ink cartridge or material reservoir is altered over time to yield initial quantitative increases in the cell density over the first several printed layers, followed by quantitative decreases in the subsequent printed layers. Finally, in the time-dependent analysis, the evolution of cell density and the emergence of material degradation effects is studied over a time course study. Variable initial cell densities (0.6 × 106 cells/ml, 1.0 × 106 cells/ml, and acellular control group) printed and cross-linked into cell-laden constructs for the 48 hr time course study exhibit a time-dependent increase in cell density owing to proliferation within the constructs that are presumed to accelerate the degradation rate.

Topics: Density , Gelatin
Commentary by Dr. Valentin Fuster
2017;():V004T05A016. doi:10.1115/MSEC2017-2898.

Organ printing, which utilizes advanced manufacturing technologies to fabricate three-dimensional (3D) functional organs based on layer-by-layer mechanism, is emerging as a promising solution to solve the organ donor shortage problem affecting all over the world. One of the biggest challenges for fabrication of functional and effective thick tissues/organs is the engineering of vascular networks. This paper introduces a Bingham fluid (Carbopol gel) to assist fabrication of 3D vascular-like constructs of interpenetrating network (IPN) hydrogels. Carbopol gel as a Bingham fluid exhibits a characteristic yield stress behavior. As the nozzle moves inside Carbopol, the shear stress is larger than the yield stress and the Carbopol gel behaves like a viscous fluid with a specific viscosity. After the nozzle moves away, the shear stress decreases below the yield stress and the Carbopol gel rapidly solidifies behaving like a solid. This unique rheological property is utilized to support and maintain the shape of the fabricated 3D structures, although the fluid printed is not crosslinked. Finally, the fabricated structures are subject to a two-step gelation process to successfully form 3D vascular-like constructs of IPN hydrogels. This novel approach enables effective and efficient fabrication of complex vascular network of IPN hydrogels.

Commentary by Dr. Valentin Fuster
2017;():V004T05A017. doi:10.1115/MSEC2017-2921.

Inkjet printing as a viable technology has been widely adapted for various biomedical applications, such as 3D biofabrication which utilizes the droplets generated from inkjet printing of bioink to build 3D viable structures. One of the key challenges is cell distribution which is cell number embedded per droplet/microsphere. It significantly affects the post-printing cell viability and proliferation. This paper focuses on the effect of excitation voltage on the living cell distribution during drop-on-demand inkjet printing of bioink containing living cells. The cell distribution results are compared under two different excitation voltages of 40V and 50V. The normal distribution is used to fit the experimental results. It is found that 1) at both 40V and 50V, the mean cell number of the experimental results is always smaller than the theoretical value due to cell motion inside the nozzle; and 2) the mean cell number errors are 3% at 40V and 18% at 50V, which is due to different ligament flow near the nozzle orifice. The resulting knowledge benefits efficient and effective fabrication of 3D cellular constructs with uniform cell distribution.

Commentary by Dr. Valentin Fuster
2017;():V004T05A018. doi:10.1115/MSEC2017-3020.

Engineered microenvironments along with robust quantitative models of cell shape metrology that can decouple the effect of various well-defined cues on a stem cell’s phenotypic response would serve as an illuminating tool for testing mechanistic hypotheses on how stem cell fate is fundamentally regulated. As an experimental testbed to probe the effect of geometrical confinement on cell morphology, poly(ε-caprolactone) (PCL) layered fibrous meshes are fabricated with an in-house melt electrospinning writing system. Gradual confinement states of fibroblasts are demonstrated by seeding primary fibroblasts on defined substrates, including a classical two-dimensional (2D) petri dish and porous 3D fibrous substrates with microarchitectures tunable within a tight cellular dimensional scale window (1–50 μm). To characterize fibroblast confinement, a quantitative 3D confocal fluorescence imaging workflow for 3D cell shape representation is presented. The methodology advanced allows the extraction of cellular and subcellular morphometric features including the number, location, and 3D distance distribution metrics of the shape-bearing focal adhesion proteins.

Commentary by Dr. Valentin Fuster
2017;():V004T05A019. doi:10.1115/MSEC2017-3050.

Additive manufacturing, also known as three-dimensional (3D) printing, is an approach in which a structure may be fabricated layer by layer. For 3D inkjet printing, droplets are ejected from a nozzle and each layer is formed droplet by droplet. Inkjet printing has been widely applied for the fabrication of 3D biological gel structures, but the knowledge of the microscale interactions between printed droplets is still largely elusive. This study aims to elucidate the alginate layer formation process during drop-on-demand inkjet printing using high speed imaging and particle image velocimetry. Droplets are found to impact, spread, and coalesce within a fluid region at the deposition site, forming coherent printed lines within a layer. Interfaces are found to form between printed lines within a layer depending on printing conditions and printing path orientation. The effects of printing conditions on the behavior of droplets during layer formation are discussed and modeled based on gelation dynamics, and recommendations are presented to enable controllable and reliable fabrication of gel structures.

Commentary by Dr. Valentin Fuster

Bio and Sustainable Manufacturing: Manufacturing Process Characterizations for System Level Sustainability Assessment

2017;():V004T05A020. doi:10.1115/MSEC2017-2734.

Biofuel manufacturing consists of two major processes, i.e., feedstock preprocessing and bioconversion. The preprocessing includes size reduction and pelleting. The bioconversion includes pretreatment, hydrolysis, and fermentation. Various studies have been implemented for these two processes. Most existing literature focuses on a specific process, while very few of them consider the possible interactions between the two processes. In this paper, we investigated the relationship between the particle size in feedstock preprocessing and the sugar yield (proportional to biofuel yield) in bioconversion. The method of design of experiments was used to design experiments and analyze the experimental results of sugar yield with different particle sizes for three different types of biomass. Critical parameters that significantly influence the sugar yield were identified. The optimal configurations of the particle size were recommended.

Commentary by Dr. Valentin Fuster
2017;():V004T05A021. doi:10.1115/MSEC2017-2970.

With the advantages of low cost and high conversion efficiency, perovskite solar cell attracts enormous attention in recent years for research and development. However, the toxicity potential of lead used in perovskite solar cell manufacturing causes grave concern for its environmental performance. To understand and facilitate the sustainable development of perovskite solar cell, a comprehensive life cycle assessment has been conducted by using attributional life cycle assessment approach from cradle to grave, with manufacturing data from our lab experiments and literature. The results indicate that the major environmental problem is associated with system manufacturing, including gold cathode, organic solvent usage and recycling, and electricity utilization in component manufacturing process. Lead only contributes less than 1% of human toxicity and ecotoxicity potentials in the whole life cycle, which can be explained by the small amount usage of lead in perovskite dye preparation. More importantly, the uncertainties caused by life cycle inventory have been investigated in this study to show the importance of primary data source. In addition, a comparison of perovskite solar cell with conventional solar cells and other dye sensitized solar cells shows that perovskite solar cell could be a promising alternative technology for future clean power generations.

Commentary by Dr. Valentin Fuster
2017;():V004T05A022. doi:10.1115/MSEC2017-3051.

Life cycle assessment software packages such as SimaPro, GaBi, and Umberto have become well-established tools for conducting environmental impact analysis. However, applications for broader sustainability assessment are limited. Recent research has developed an information modeling framework to compose models of unit manufacturing processes for sustainability assessment and has led to the definition of unit manufacturing process information modeling concepts. An engineer can use the framework to conduct manufacturing system-level sustainability assessments by composing models of unit manufacturing processes. Assessment results can aid engineers in selecting the superior manufacturing process flow for a given product. To demonstrate usefulness of the information framework, a prototype desktop application has been developed. The application was implemented in Windows Project Foundation (WPF) using C# as the coding language to create a graphical user interface. Mathworks MATLAB serves as the calculation engine. Unit manufacturing process models follow the framework and are read by the application, which produces a sustainability assessment for the manufacturing process flow. A manufacturing process flow for an automobile-like metal product acts is used to demonstrate the software application.

Commentary by Dr. Valentin Fuster

Bio and Sustainable Manufacturing: Sustainability in Smart Manufacturing: Analysis, Metrics, and Modeling Tools

2017;():V004T05A023. doi:10.1115/MSEC2017-2630.

In order to help manufacturing companies quantify and reduce product carbon footprints in a mixed model manufacturing system, a product carbon footprint oriented multi-objective flexible job-shop scheduling optimization model is proposed. The production portion of the product carbon footprint, based on the mapping relations between products and the carbon emissions within the manufacturing system, is proposed to calculate the product carbon footprint in the mixed model manufacturing system. Non-Dominated Sorting Genetic Algorithm-II (NSGA-II) is adopted to solve the proposed model. In order to help decision makers to choose the most suitable solution from the Pareto set as its execution solution, a method based on grades of product carbon footprints is proposed. Finally, the efficacy of the proposed model and algorithm are examined via a case study.

Commentary by Dr. Valentin Fuster
2017;():V004T05A024. doi:10.1115/MSEC2017-2733.

Cellulosic biofuel manufacturing consists of two major processes, biomass feedstock preprocessing and bioconversion. Traditionally, these two processes are conducted in different locations in practice and transportation is required to connect the two processes. Pelleting in preprocessing can help reduce the size and increase the density of biomass so that the transportation and handling can be more efficient. However, pelleting is also considered an energy-intensive process that consumes a large amount of energy, which leads to considerable greenhouse gas emissions. Due to such an environmental and energy related concern, the use of pelleting process in real industry is still in doubt regarding its performance of environmental sustainability although it has been extensively studied in laboratory scale. In this paper, we analyze both positive and negative impacts of pelleting in biofuel manufacturing regarding GHG emissions. A numerical case study focusing on the transportation is conducted to examine such impacts through the comparison between the scenarios with and without pelleting process to estimate the net emission due to the pelleting process.

Commentary by Dr. Valentin Fuster
2017;():V004T05A025. doi:10.1115/MSEC2017-2854.

In this paper, a manufacturing work cell with a gantry that is in charge of moving materials/parts between machines and buffers is considered. With the effect of the gantry movement, the system performance becomes quite different from traditional serial production lines. In this paper, reinforcement learning is used to develop a gantry scheduling policy in order to improve system production. The gantry learns to take proper actions under different situations to reduce system production loss by using Q-Learning algorithm and finds the optimal moving policy. A two-machine one-buffer work cell with a gantry is used for case study, by which reinforcement learning is applied. Compare with the FCFS policy, the fidelity and effectiveness of the reinforcement learning method are also demonstrated.

Commentary by Dr. Valentin Fuster
2017;():V004T05A026. doi:10.1115/MSEC2017-2874.

The design of a high precision machine tool presents one main goal for an engineer: to maximize productivity while minimizing resource inputs and wasted outputs. Incorporating additional design requirements to improve the sustainability of the machine tool presents challenges to design engineers. Should productivity be sacrificed for resource efficiency improvements? Previous tools used for incorporating sustainability principles into design provide guidance but lack necessary detail for making informed decisions, or the tools rely on the engineer’s previously developed knowledge in sustainable design. Axiomatic design, being an already accepted system design framework, provides an opportunity to incorporate sustainability considerations into the core of design activities rather than having sustainability be a side activity. A methodology for designing sustainable machine tools using axiomatic design is presented, and a case study on a grinding machine is investigated. A list of hypothetical sustainability axioms are proposed, similar to how the original axioms of axiomatic design were proposed. The axioms are then discussed using the example of a grinding machine tool.

Commentary by Dr. Valentin Fuster
2017;():V004T05A027. doi:10.1115/MSEC2017-2877.

The need for an open, inclusive, and neutral procedure in selecting key performance indicators (KPIs) for sustainable manufacturing has been increasing. The reason is that manufacturers seek to determine what to measure in order to improve environmental sustainability of their products and manufacturing processes. A difficulty arises in understanding and selecting specific indicators from a large number of stand-alone indicator sets available. This paper presents a procedure for individual manufacturers to select KPIs for measuring, monitoring and improving environmental aspects of manufacturing processes. The procedure is the basis for a guideline, being proposed for standardization within ASTM International. That guide can be used for (1) identifying candidate KPIs from existing sources, (2) defining new candidate KPIs, (3) selecting appropriate KPIs based on KPI criteria, and (4) composing the selected KPIs with assigned weights into a set. The paper explains how the developed procedure complements existing indicator sets and sustainability-measurement approaches at the manufacturing process level.

Commentary by Dr. Valentin Fuster
2017;():V004T05A028. doi:10.1115/MSEC2017-2879.

In the aerospace industry, titanium (Ti) alloys, especially Ti6Al4V, has been extensively used over other light weight alloys due to their high strength-to-weight ratio. However, the material and production costs have been major obstacles in the adoption of Ti alloys for a wide variety of applications. The machining of Ti alloys is one of the most time consuming and expensive mechanical processes in aerospace manufacturing. Based on previous literature on the topic, coated drills have had some degree of success in the drilling of Ti. To further the work, this paper conducts a comparative study in which Ti6Al4V plates are drilled with super hard coated drills such as Diamond-like-Carbon (DLC), AlMgB14 (BAM) and nanocomposite AlCrSiN. The results are compared with those of an uncoated drill bit. Working with a coating supplier, several variations of BAM coating have been applied and used in our drilling experiments. To evaluate the performance of these drills, scanning electron microscopy and confocal laser microscopy were used to assess the wear progress of each drill qualitatively and quantitatively. In drilling Ti alloys, the primary mechanisms of flank wear are abrasion, microscopic fracture (chipping) and attrition, which result in the detachment of the adhesion layer located at the cutting edge. For all the drills, the predominant wear occurs near the margin. From our drilling experiments, it has been observed that AlCrSiN and BAM drills have survived up to 58 holes and over 80 holes, respectively, while both uncoated and DLC drills have experienced catastrophic fracture at less than 40 holes.

Commentary by Dr. Valentin Fuster
2017;():V004T05A029. doi:10.1115/MSEC2017-2907.

This paper explores the potential of Gaussian process based Metamodels for simulation optimization with multivariate outputs. Specifically we focus on Multivariate Gaussian process models established through separable and non-separable covariance structures. We discuss the advantages and drawbacks of each approach and their potential applicability in manufacturing systems. The advantageous features of the Multivariate Gaussian process models are then demonstrated in a case study for the optimization of manufacturing performance metrics.

Commentary by Dr. Valentin Fuster
2017;():V004T05A030. doi:10.1115/MSEC2017-2930.

The scheduling of manufacturing equipment is critical in production facilities. Research on production scheduling has traditionally focused on component throughput and cycle time. However, the increase of electricity price in the United States following the market deregulation in 1990s has led to efforts to reduce energy cost via manufacturing scheduling. This paper explores the possibility of reducing electricity cost of a manufacturing facility subject to real time electricity pricing by dynamically changing operation schedules, while maintaining a pre-determined production throughput. A time series model is developed to forecast the hourly electricity price and time-indexed integer programming is used to determine the manufacturing schedule. The electricity price forecast is updated every hour based on the price history, and manufacturing schedule is updated according to the updated price forecast. A hypothetical flow line with 3 processes operating 16 hours per day is used as a case study. The line has a limited public buffer between processes and all machines in the shop have three operational states. With a throughput of 60 parts per day, the results suggest that it is possible to reduce the cost by 3.6% using an hourly forecast compared with a schedule based on a day-ahead price forecast.

Topics: Manufacturing
Commentary by Dr. Valentin Fuster
2017;():V004T05A031. doi:10.1115/MSEC2017-2941.

For multi-stage manufacturing system, considerable amount of energy may be wasted and energy efficiency may be hindered due to idleness or constraints from the interactions between the machines and buffers. In this paper, a real-time system performance diagnostic method is developed to identify energy waste due to machine and buffer interactions, and system resilience against random disruption events. Furthermore, by utilizing the real-time system diagnostic information, a novel real-time resilient feedback control policy is proposed to improve system energy efficiency and deliver resilient performance against random disruption events. A case study is presented to demonstrate the effectiveness of the proposed control policy.

Commentary by Dr. Valentin Fuster
2017;():V004T05A032. doi:10.1115/MSEC2017-2985.

Driven by the green logistics, automated guided vehicle (AGV) has been widely accepted as a new transportation tool for in-house logistics, which enables a timely supply of parts to the designated workstations with less energy consumption. However, the existing scheduling methods for AGV scheduling are designed to minimize inventory or cost without explicitly considering energy saving. To fill the gap, this paper proposes an AGV scheduling model for energy saving in a mixed-model assembly line, where AGVs can have variable travel speeds. A mixed-integer model is constructed and an exact solution procedure is provided. Simulation studies are performed to investigate the main factors that determine the energy consumption and to demonstrate the effectiveness of the proposed method.

Commentary by Dr. Valentin Fuster
2017;():V004T05A033. doi:10.1115/MSEC2017-2994.

The energy usage inside of a manufacturing plant is mainly from two sources: energy demand from the production lines to support manufacturing processes, and the plant building temperature control to maintain a comfortable working environment. It is reported that in the US, 14% of the primary energy and 32% of electricity is used by the industry and commercial building heating, ventilation and air conditioning (HVAC) system. As an important part of the HVAC system, the air handler unit (AHU) is a comprehensive air control system consisting of multiple sub-units. Accurate modeling of the supply air temperature of AHU is important for later controller design and fault detection, but it is also challenging because of the application of variable frequency drive (VFD) systems, overall degradation, and limited sensor information and meter data. Parameter estimation of the industry AHU is therefore worth studying. In this study, the authors intend to establish a deterministic physical model of AHU system, identify the unknown parameters based on the limited meter inputs, and compare the nonlinear parameter estimation results with the design parameters, in order to achieve the goal of improving the modeling accuracy without installing expensive metering systems.

Commentary by Dr. Valentin Fuster
2017;():V004T05A034. doi:10.1115/MSEC2017-3047.

We provide a cloud manufacturing based manufacturing planning framework for small and medium-sized enterprises. Manufacturing planning is conducted by separate units in the cloud instead of in corporations or manufacturing platforms. Disorders can be removed by the adoption of our newly-introduced units. To retain the workability of our new framework, three assumptions are imposed. A concrete case on process planning and scheduling is used for illustration of the necessity of our assumptions and operational mechanism of our design. Finally, a preliminary discuss on how intellect resources as well as small and medium-sized enterprises are involved to create a sustainable environment for small and medium-sized enterprises is placed.

Commentary by Dr. Valentin Fuster

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