bluuebunny/crossref_metadata_2025 huggingface dataset:
Contract farming and everyday acts of resistance: Oil palm contract farmers in the Philippines
Authors: Hambloch Caroline
Published: November 2021

Contract violations are critical issues determining the success and sustainability of contract farming (CF). This paper challenges the common portrayal of the “powerful” company versus the “powerless” landowners/smallholders by using the literature on labour agency in global value chains to understand minor contract violations of contract farmers such, as side‐selling, refusal to harvest, and burning/felling of oil palm trees. This paper conceptualizes these violations as acts of minor agency or everyday acts of resistance. The analysis highlights how CF has created chains of dependency, in which smallholders are integrated into the modern market economy through new relations of debt and power. In response, contract farmers attempt to influence and shape the CF relation by using these different acts of minor agency. This paper finds that acts of minor agency, in the aggregate, can have important effects on contract relations, governance, and organizational structure of the chain and has the potential to lead to broader changes in the underlying social relations of contract. It highlights howindividualacts of minor agency may contribute to the development of a consciousness ofcollectiveopposition to the contract relation.
Do Taiwanese Undergraduate Students with SLD Use Different Learning Strategies than Students without These Disabilities?
Authors: Wang Li‐Chih , Chung Kevin Kien Hoa
Published: November 2021

This study investigated the learning strategies that university students with specific learning disabilities (SLD) report using in the Chinese language context. Participants were 105 first‐year undergraduate students with SLD and 134 typically developing peers. Three questionnaires about reported reading/writing difficulties, metacognitive knowledge, and learning strategies were administered. Students with SLD reported using fewer learning strategies than students without SLD. The use of writing/research skills, which are the skills used to research topics from various sources in different ways (e.g., organizing writing projects, and monitoring for errors), significantly negatively predicted the reported reading/writing difficulties in both groups. These findings help expand our understanding of which learning strategies are useful for students with SLD and university instructors use more suitable techniques to facilitate the learning of these students.
Inter‐species lateral gene transfer focused on the Chlamydia plasticity zone identifies loci associated with immediate cytotoxicity and inclusion stability
Authors: Dimond Zoe E. , Suchland Robert J. , Baid Srishti , LaBrie Scott D. , Soules Katelyn R. , Stanley Jacob , Carrell Steven , Kwong Forrest , Wang Yibing , Rockey Daniel D. , Hybiske Kevin , Hefty P. Scott
Published: November 2021

Chlamydia muridarum actively grows in murine mucosae and is a representative model of human chlamydial genital tract disease. In contrast, C. trachomatis infections in mice are limited and rarely cause disease. The factors that contribute to these differences in host adaptation and specificity remain elusive. Overall genomic similarity leads to challenges in the understanding of these significant differences in tropism. A region of major genetic divergence termed the plasticity zone (PZ) has been hypothesized to contribute to the host specificity. To evaluate this hypothesis, lateral gene transfer was used to generate multiple hetero‐genomic strains that are predominately C. trachomatis but have replaced regions of the PZ with those from C. muridarum. In vitro analysis of these chimeras revealed C. trachomatis‐like growth as well as poor mouse infection capabilities. Growth‐independent cytotoxicity phenotypes have been ascribed to three large putative cytotoxins (LCT) encoded in the C. muridarum PZ. However, analysis of PZ chimeras supported that gene products other than the LCTs are responsible for cytopathic and cytotoxic phenotypes. Growth analysis of associated chimeras also led to the discovery of an inclusion protein, CTL0402 (CT147), and homolog TC0424, which was critical for the integrity of the inclusion and preventing apoptosis.
A group I WRKY transcription factor regulates mulberry mosaic dwarf‐associated virus‐triggered cell death in Nicotiana benthamiana
Authors: Sun Shaoshuang , Ren Yanxiang , Wang Dongxue , Farooq Tahir , He Zifu , Zhang Chao , Li Shifang , Yang Xiuling , Zhou Xueping
Published: November 2021

Geminiviruses constitute the largest group of known plant viruses and cause devastating losses to a wide range of crops and woody plants globally. Mulberry mosaic dwarf‐associated virus (MMDaV), identified from Chinese mulberry trees via small RNA‐based deep sequencing, is a divergent monopartite geminivirus belonging to the genus Mulcrilevirus of the family Geminiviridae. Previous studies have shown that plants employ multiple layers of defence to protect themselves from geminivirus infection. The interplay between plant and MMDaV is nevertheless less studied. This study presents evidence that MMDaV triggers hypersensitive response (HR)‐mediated antiviral defence in Nicotiana benthamiana plants. We show that the RepA protein of MMDaV is engaged in HR‐type cell death induction. We find that the RepA mutants with compromised nuclear localization ability impair their capabilities of cell death induction. Virus‐induced gene silencing of the key components of the R protein‐mediated signalling pathway reveals that down‐regulation of the nucleus‐targeting NbWRKY1 alleviates the cell death induction activity of RepA. We further demonstrate that RepA up‐regulates the transcript level of NbWRKY1. Furthermore, expression of RepA in N. benthamiana confers plant resistance against two begomoviruses. We propose that plant resistance against RepA can be potentially used to improve plant defence against geminiviruses in crops.
Does quality of orthodontic treatment outcome influence post‐treatment stability? A retrospective study investigating short‐term stability 2 years after orthodontic treatment with fixed appliances and in the presence of fixed retainers
Authors: Gera Arwa , Gera Shadi , Cattaneo Paolo M. , Cornelis Marie A.
Published: November 2021

Objective

The present study aimed to evaluate stability 2 years after orthodontic treatment and to investigate the influence of various pre‐treatment and post‐treatment prognostic factors on stability.

Setting and Sample Population.

Consecutive patients treated with full fixed appliance and retained with fixed retainers were retrospectively assessed for eligibility.

Materials and Methods

Digital models were analysed at treatment start (T0), end of treatment (T1) and 2 years post‐treatment (T2). The Peer Assessment Rating (PAR) index, Little's Irregularity Index (LII), arch width and length, overjet, overbite and presence of unexpected post‐treatment changes were assessed. Multiple regression analyses were conducted to model the relationship of all outcomes with several prognostics simultaneously.

Results

The sample consisted of 287 subjects (mean treatment time: 25.1 months, standard deviation [SD] 7.5; mean post‐treatment follow‐up: 27.5 months, SD 6.1) with a mean weighted PAR score of 29.5 (SD 8.6) at T0, 1.8 (SD 2.9) at T1 and 3.2 (SD 3.6) at T2. At T1, 95% of the subjects had a perfect LII versus 86% at T2. An increased LII at T1 correlated with increased LII and PAR changes from T1 to T2. PAR at T1 as well as overjet at T0 was a significant prognostic factor for PAR at T2. At T2, five cases (1.7%) showed unexpected post‐treatment changes related to fixed retainers.

Conclusion

Short‐term post‐treatment stability with fixed retainers was very good. Prognostic factors for stability included LII and PAR at T1, suggesting that high‐quality treatment outcome in the presence of fixed retainers may ensure post‐treatment stability.
Selective deep lobe parotidectomy via retroauricular hairline (Roh's) incision for deep lobe parotid pleomorphic adenoma
Authors: Roh Jong‐Lyel
Published: November 2021

Objective

Deep lobe parotid tumour is commonly removed with the covering superficial lobe of parotid gland. Total or subtotal parotidectomy leads to an increase in surgical morbidity. This study evaluated recurrence and function after selective deep lobe parotidectomy via retroauricular hairline (Roh's) incision for pleomorphic adenoma.

Materials and methods

Twenty‐eight patients with deep lobe parotid pleomorphic adenomas underwent selective deep lobe parotidectomy with preservation of the superficial lobe and the facial lobe via Roh's incision. Each patient was evaluated with any complications, cosmetic and salivary functions and local recurrence.

Results

Superficial lobe‐preserving surgery via Roh's incision was successfully applied to all patients without injury to the facial nerve and the Stensen's duct for a median operation time of 65 min. Facial nerve paralysis was found only temporarily in 9 (32%) patients, and other complications were minimal. None of the patients had postoperative Frey's syndrome. Salivary secretory function in the operated side was well preserved. No recurrence was found in the patients for a median follow‐up of 94 months.

Conclusions

Selective deep lobe parotidectomy via Roh's incision is a reliable option of treatment for deep lobe parotid pleomorphic adenoma.
Case report of a challenging medium‐sized congenital melanocytic nevus (CMN): Highlighting a role for reflectance confocal microscopy (RCM) for evaluating changing CMN in children
Authors: Haefliger Stefanie , Guitera Pascale , Melhoranse Gouveia Bruna , Colebatch Andrew J. , Scolyer Richard A. , Rtshiladze Michael , Martin Linda K.
Published: November 2021

A 3.5‐month‐old boy presented with a changing medium‐sized congenital melanocytic nevus on his leg. Due to atypical features on dermoscopy and reflectance confocal microscopy (RCM), an excision of the area of concern was performed. Histopathology showed many of the pathological features usually associated with a diagnosis of melanoma in situ in older patients, but due to the young age of the patient, absence of mitoses, and the degree of atypia, a diagnosis of a dysplastic compound nevus arising in a congenital compound (predominantly dermal) nevus was favored. In our case, RCM corresponded to histopathology helped target the area of concern and map the clinical and subclinical components to facilitate an optimal biopsy.
Immediate response of Chara braunii exposed to zinc and hydrogen peroxide
Authors: Herbst Anne , Ranawakage Viraj , Asaeda Takashi , Schubert Hendrik
Published: November 2021

The immediate effect of zinc (Zn) and hydrogen peroxide (H2O2) in Chara braunii was analyzed in short‐time exposure experiments. The exposure concentrations were 12.3, 18.4, and 24.5 μmol L−1 H2O2, 12, 60, and 120 mg L−1 Zn, and 12.3 μmol L−1 H2O2 + 12 mg L−1 Zn, 12.3 μmol L−1 H2O2 + 60 mg L−1 Zn, and 18.4 μmol L−1 H2O2 + 12 mg L−1 Zn. The stress response of C. braunii was analyzed by measuring photosynthetic photosystem II activity, chlorophyll a and b and carotenoid contents, the H2O2 concentration, and antioxidant enzyme activities of ascorbic peroxidase, catalase, and guaiacol peroxidase. The short‐term addition of Zn reduced pigment contents in C. braunii. Chlorophyll a and b and carotenoid contents in H2O2‐exposed C. braunii were as high as in control plants. Photosynthesis was reduced in H2O2‐treated C. braunii and the short‐term addition of Zn did not affect the electron transport rate. H2O2 concentration and antioxidant enzyme activities in C. braunii were not significantly different between control and exposed plants. Trends of enzymatic adaptation were described: the H2O2‐induced stress response was characterized by increased antioxidant enzyme activities, whereas Zn inactivated catalase in C. braunii.
Investigating the susceptibility to change of coping and resiliency during COVID‐19
Authors: Godor Brian P. , Van der Hallen Ruth
Published: November 2021

On 11 March 2020 the World Health Organization (WHO) declared the outbreak of the novel coronavirus SARS‐CoV‐2 (COVID‐19) a global pandemic. As a result, most of public life, including cultural, sporting, religious and political events, came to a standstill. The current study investigates potential changes in individual’s coping and resiliency during this phase of the pandemic. The present study investigated potential changes in individuals’ coping and resilience during the COVID‐19 pandemic. Participants (N = 68), aged between 18 and 34 years old, completed an online survey including the Brief‐COPE (Coping Orientation to Problems Experienced) and the SPF‐24 (Scale of Protective Factors) at two distinct time points: May 2019 (T0) and May 2020 (T1). To investigate changes between T0 and T1, one‐way within‐subjects analysis of variances (ANOVAs)’s were conducted. For 11 of 14 the subscales for the Brief‐COPE, no significant within‐subject sum scores changes were revealed. However, for three subscales, that is, Active Coping (p = 0.005), Venting (p = 0.024) and Acceptance (p = 0.028), significant sum scores changes were revealed. For all four subscales for the SPF‐24, no significant within‐subjects sum score changes were revealed. For the Brief‐COPE, the susceptibility to change for only three of the 14 coping strategies to be significantly influenced by COVID‐19, reveals a strong trait‐like character of one’s coping strategies. For the SPF‐24, all four protective factors were not susceptible to significant changes due to individuals’ experiences of COVID‐19.
Black monument matters: Place‐based commemoration and abolitionist memory work
Authors: Moulton Alex A.
Published: November 2021

Discrete monuments remain in the domain of the symbolic, land as mnemonic shifts to a more materialist commemorative praxis. This paper proposes a turn toward land as mnemonic of Black freedom struggle and place‐making. Reviewing the scholarship on memoryscapes, I show that the critical insights of Black ecologies and geographies scholarship has moved further than traditional scholarship and offers multiple openings for new monuments and commemorative practices in honor of Black life. Black socio‐ecologies scholarship centralizes the place‐based epistemologies, spatial histories, and experiences of Black communities and clarifies the form and function of land or plots as mnemonics of the Black freedom struggle, place‐making practices, and spatial epistemologies. Black plots are, therefore, ideal for orienting a new mode of Black commemoration. While much of the paper centers monuments to Black people, if Black commemoration is foregrounded in abolitionists thinking and practices, such memorialization must grapple with the histories of Indigenous dispossession and settler‐colonialism. The paper concludes with a consideration of what the argument for land as mnemonic of Black freedom struggle and place‐making might mean for future avenues of research.
Phrase Embedding and Clustering for Sub-Feature Extraction From Online Data
Authors: Park Seyoung , Kim Harrison M.
Published: November 2021

Recently, online user-generated data have been used as an efficient resource for customer analysis. In the product design area, various methods for analyzing customer preference for product features have been suggested. However, most of them focused on feature categories rather than product components which are crucial in practical applications. To address that limitation, this paper proposes a new methodology for extracting sub-features from online data. First, the method detects phrases in the data and filtered them using product manual documents. The filtered phrases are embedded into vectors, and then they are divided into several groups by two clustering methods. The resulting clusters are labeled by analyzing items in each cluster. Finally, cue phrases for sub-features are obtained by selecting clusters with labels representing product features. The proposed methodology was tested on smartphone review data. The result provides feature clusters containing sub-feature phrases with high accuracy. The obtained cue phrases will be used in analyzing customer preferences for sub-features and this can help product designers determine the optimal component configuration in embodiment design.
A Reliability-Based Formulation for Simulation-Based Control Co-Design Using Generalized Polynomial Chaos Expansion
Authors: Behtash Mohammad , Alexander-Ramos Michael J.
Published: November 2021

Combined plant and control design (control co-design (CCD)) methods are often used during product development to address the synergistic coupling between the plant and control parts of a dynamic system. Recently, a few studies have started applying CCD to stochastic dynamic systems. In their most rigorous approach, reliability-based design optimization (RBDO) principles have been used to ensure solution feasibility under uncertainty. However, since existing reliability-based CCD (RBCCD) algorithms use all-at-once formulations, only most-probable-point (MPP) methods can be used as reliability analysis techniques. Though effective for linear/quadratic RBCCD problems, the use of such methods for highly nonlinear RBCCD problems introduces solution error that could lead to system failure. A multidisciplinary feasible (MDF) formulation for RBCCD problems would eliminate this issue by removing the dynamic equality constraints and instead enforcing them through forward simulation. Since the RBCCD problem structure would be similar to traditional RBDO problems, any of the well-established reliability analysis methods could be used. Therefore, in this work, a novel reliability-based MDF formulation of multidisciplinary dynamic system design optimization has been proposed for RBCCD. To quantify the uncertainty propagated by the random decision variables, Monte Carlo simulation has been applied to the generalized polynomial chaos expansion of the probabilistic constraints. The proposed formulation is applied to two engineering test problems, with the results indicating the effectiveness of both the overall formulation as well as the reliability analysis technique for RBCCD.
Influence of Intake Pipe Deflection Angle on In-Cylinder Flow and Combustion Characteristics of a Rotary Engine
Authors: Deng Xiwen , Feng Zhan , Lei Jilin , Liu Yi , Jia Dewen
Published: November 2021

Intake pipe design is important for rotary engine performance due to great influence on in-cylinder flow and combustion characteristics. This paper analyzes the effect of intake pipe deflection angle on the performance of a gasoline rotary engine. In the parametric study, the intake pipe is deflected from the left to the right with a 10 deg interval and the maximum deflection range of 30 deg at each side. A computational fluid dynamics numerical simulation model of the rotary engine is established. The simulation results show that when the intake pipe is deflected to the left from the original design, the engine volumetric efficiency first increases and then decreases with an increasing deflection angle. During ignition, the turbulent kinetic energies in the cylinder increase with an increasing deflection angle. When the intake pipe is deflected to the left by 30 deg, the turbulent kinetic energy is increased by 85.9% compared to the original design. The peak cylinder pressures first increase and then decrease with an increasing deflection angle. When the intake pipe is deflected by 10 deg to the left, the peak cylinder pressure is 9.3% higher than that of the original design. The maximum NOx emission can be increased by 4.8% and the minimum NOx emission can be decreased by 13.3%. It is found that deflecting the intake pipe to the left enhances the tumble effect and increases the combustion velocity. Overall, deflecting the intake pipe to the right is less effective than deflecting to the left. This analysis provides a comprehensive understanding on intake pipe design for rotary engines.
A Grinding-Burnishing Approach to Enhancing Surface Integrity, Tribological, and Corrosion Behavior of Laser-Cladded AISI 431 Alloys
Authors: Uddin Mohammad , Santifoller Remi , Hall Colin , Schlaefer Thomas
Published: November 2021

This paper presents the influence of the grinding-burnishing on surface integrity and corrosion performance of the laser-cladded AISI 431 alloys. As-cladded specimens were first ground followed by ball burnishing. To evaluate surface alteration and performance enhancement, six major properties were measured and analyzed in terms of surface roughness, porosity, microhardness, wear, and impact and corrosion resistance. Results showed that grinding-burnishing significantly improved the surface finish by lowering Ra and Rz by up to 29% and 41%, respectively, compared with grinding. Surface porosity was found to decrease by 18%. Maximum surface microhardness increased by 32% when grinding-burnishing, with a modified depth of up to 250 µm, while wear resistance in terms of volume loss increased by up to 38%. Because of hardness improvement, the grinding-burnishing increased the impact resistance by lowering the maximum indent depth by 29%. The corrosion resistance improved by increasing positive corrosion potential from −0.31 V (grinding) to −0.21 V (grinding-burnishing) and lowering corrosion current density from 1.18 × 10−3 A.cm−2 (for grinding) to 2.1 × 10−5 A.cm−2 (grinding-burnishing). Burnishing further induced grain modification in terms of grain deformation and flattening within microstructure, but no grain refinement was observed. XRD results however showed lattice deformation indicating potential compressive residual stress generated by burnishing. Overall, it is imperative to say that the combined grinding-burnishing can be a viable surface modification technique to extend functional service life of the laser-cladded components.
Vibration-Based Fault Diagnosis of Helical Gear Pair With Tooth Surface Wear Considering Time-Varying Friction Coefficient Under Mixed Elastohydrodynamic Lubrication Condition
Authors: Wang Siyu , Zhu Rupeng
Published: November 2021

Based on “slice method,” the improved time-varying mesh stiffness (TVMS) calculation model of helical gear pair with tooth surface wear is proposed, in which the effect of friction force that obtained under mixed elastohydrodynamic lubrication (EHL) is considered in the model. Based on the improved TVMS calculation model, the dynamic model of helical gear system is established, then the influence of tooth wear parameters on the dynamic response is studied. The results illustrate that the varying reduction extents of mesh stiffness along tooth profile under tooth surface wear, in addition, the dynamic response in time-domain and frequency-domain present significant decline in amplitude under deteriorating wear condition.
Post-Processing Deflectometry Grid Images Using Particle Image Velocimetry Analysis
Authors: O’Donoughue Patrick , Robin Olivier , Rouard Kevin , Le Bot Alain , Berry Alain
Published: November 2021

Deflectometry is a full-field optical technique for surface slope measurement based on recording the deformation of a grid image. A hybrid method is explored in which the grid images from a deflectometry measurement are processed using a particle image velocimetry analysis tool. The hybrid approach is compared to a common phase shifting algorithm for grid images based on a windowed discrete Fourier transform. The resulting slope maps compare well with those identified using the spatial phase shifting procedure. While the traditional phase shifting method has a tuning requirement that limits the optical setup to configurations that produce an integer number of pixels per grid period in the image, the use of particle image velocimetry analysis omits this calibration step. The applicability of an existing turnkey tool to perform full-field vibration imaging using deflectometry can benefit to research concerning mechanical vibration and related experimental methods.
Damage Detection of CFRP Pipes and Ladder Structure by Using Localized Flexibility Method
Authors: Aoki Yoshio , Shoji Akiko , Byon O-Il
Published: November 2021

This paper presents modal-based structural damage detection. Specifically, we focus on localized flexibility properties that can be deduced from the experimentally determined global flexibility matrix. We present the underlying theory that can be viewed a generalized flexibility formulation in three different generalized coordinates, viz., localized or substructural displacement-basis, elemental deformation-basis and element strain-basis. Then, the present methods are applied to a CFRP pipes and shells having interior damage and the numerical and experimental results show that the elemental strain-basis method is quite useful for detecting the inside damage of the CFRP filament winding pipes.
Sliding Mode Control for the Vibration Suppression of an Inflatable Torus Using Smart Materials
Authors: Jha Akhilesh , Kim Myung-Hyun , Leo Donald J. , Inman Daniel J.
Published: November 2021

A toroidal structure is an important part of many space-based inflatable structure designs. In this work, we have tried to control the vibration of an inflated torus by means of PVDF actuators and sensors using analytical methods. We present an analytical solution of the free transverse vibration problem of the torus under internal pressure. Then piezoelectric film (PVDF) patches, attached to the surface of the torus, are modeled as uators and sensors, and the control problem is formulated in state space. A controller is designed using sliding mode control technique, which provides robust vibration control performance in the presence of modeling error and parameter variations. The performance of the compensator is found to be satisfactory suggesting that smart materials can be successfully used in controlling inflatable toroidal space structures.
Analysis on Friction Characteristic Between Static Shell and Moving Cylinder in the Rotating Cylinder Compressor Based on CFD Method
Authors: Peng Xueyuan , He Zhilong , Zhang Wei , Shu Pengcheng
Published: November 2021

Rotating cylinder compressor is a new type of machine, which has an advantage over the reciprocating compressor in that it has no valves and represents no inertia forces. The authors have developed a prototype compressor of this kind successfully and performance test is being conducted. Preliminary running test shows that the friction occurring between the static shell and the moving cylinder is serious, which is attributed to eccentric motion of the cylinder. In this paper, friction characteristic between the static shell and the moving cylinder is investigated theoretically and experimentally. Firstly, on the basis of hydrodynamic lubrication theory and CFD method, a calculation model on motion of the cylinder in the rotating cylinder compressor is established, and the axis locus of the cylinder is calculated. Secondly, friction power caused by eccentric motion of the cylinder is estimated. Finally, experiments for verifying the calculations on the friction power are carried out. It is shown that the calculations have a fairly good agreement with the experimental data. Owing to existence of the piston holes in the cylinder, oil pressure distribution within the gap between the shell and the cylinder is not uniform, thus resulting in serious eccentricity of the cylinder. In order to improve performance and reliability of the rotating cylinder compressor, optimum design for length of the cylinder is suggested.
Simulation of Automotive LiBr/H2O Absorption A/C Machine
Authors: Salim Munther
Published: November 2021

LiBr/Water absorption refrigeration cycle for automotive air-conditioning applications was simulated, studied and analyzed using ABSIM, a user oriented computer code designed for cycle simulation of absorption systems at steady state. This cycle would utilize the available combustion engine exhaust heat to supply energy to the generator. The design parameters and ambient conditions were chosen based on conditions under which automotive vehicles would operate in practice. Condenser and evaporator sizes and air-flow quantities were chosen to be similar to their counterparts in the current R-134a vapor compression cycle. The cycle would deliver up to 7 kW of refrigeration at maximum rated conditions. The COP is 0.72. It was concluded that generator temperature of 100°C is capable of producing the maximum capacity. Also, an exhaust temperature of 285 °C and flow rate of 0.046 kg/s are required to maintain a generator temperature at 100°C. Simulation results indicate that a satisfactory operation can be established in the high ambient temperature of 45°C with air-cooled condenser and absorber.

Simulation results for the proposed cycle include temperature, enthalpy, flow rate, concentration, pressure, and vapor fraction at each point in the cycle. Also, For each component of the cycle, UA, NTU, Effectiveness, CAT, LMTD, and heat duty are presented. Global parameters such as COP and capacity are also given. Plots were generated to understand the effect of generator temperature on other components and on the cycle performance.
Thermodynamic Optimization of Electric Water Heating With Fully-Mixed Storage: First Law Efficiency
Authors: Homan K. O.
Published: November 2021

The energy consumed for water heating is a significant fraction of the total national use. The most common water heater design, particularly at the residential level, incorporates thermal storage capacity to accommodate the typically high energy withdrawal rates. For electric water heaters, the only significant loss mechanism is ambient heat exchange. In the present paper, three different configurations consisting of a fully-mixed storage vessel and an electric heating element are analyzed. Compared on the basis of equal performance, defined as a sustained draw at or above a minimum energy discharge rate, the configurations are shown to require significantly different storage volumes for identical energy input rates. Accounting for ambient heat loss, these differences in storage volume are shown to translate into appreciably higher thermal efficiencies for the configuration with the smallest required storage volume.
Characteristics Map of IGCC System in All Operating Regions
Authors: Duan L. , Lin R. , Jin H. , Cai R.
Published: November 2021

This paper studies the whole-load thermal characteristic of IGCC system. IGCC is one of advanced clean coal power generation systems. At present, it has been operationally demonstrated in the world. However theoretical researches on it are still insufficient, especially researches on off-design characteristic. Based on the idea of independent variable, we have analyzed key factors, which influence the performance of the system, and constructed a whole-load characteristic map. On the basis of generalization and modular modeling idea of total energy system, the whole-load characteristic models of key components and subsystems are built and the corresponding programs are developed. A group of whole-load characteristic curves of IGCC system under different conditions has been obtained and then the typical off-design rules of system have been summed up and the whole-load characteristic has been mapped out. The whole load characteristic map has revealed the typical off-design rules of IGCC system, and from it several valuable conclusions can be drawn. These conclusions and typical rules provide the specific information and basic data for further study on operation characteristic, control rule, system design and optimization of IGCC system.
Design, Development and Fabrication of Miniaturized Acoustical Lenses Using Micromanufactured Molds
Authors: Morley Andrew T. , Rock Andrea , Volz Justin , Roussel Thomas J. , McGuyer J. Clay , Keynton Robert S. , Friedrich Craig R.
Published: November 2021

Pulse Ultrasonic Doppler Velocimetry (PUDV) transducers have been used in the study of fluid wall shear stress and intimal hyperplasia within vascular bypass grafts [1]. Although these devices have contributed significantly to the understanding between fluid mechanic and biological phenomena, errors as large as 20% have been reported [1] within theses devices. This level of error is unacceptable to many researchers, so methods must be developed to increase accuracy within PUDV devices. One technique commonly used in ultrasonic transducers is the application of acoustical lenses. Acoustical lenses have been found to focus the ultrasonic beam, increase the spatial resolution, and increase the signal-to-noise ratio (SNR) of acoustic sensors [2]. First attempts within our laboratory to develop these lenses consisted of placing PZT-5A piezoelectric crystals within micromachined polymethylmethacralate (PMMA) blanks milled with a 263 microns deep cavity. Subsequently, Eccosorb CR-112 epoxy was cast over the crystals and machined via diamond tuming/micro-lathe to form the lens. The crystal-lens systems were then released by placing the PMMA blanks in a solvent (Dichloromethane). This process was both time consuming and only produced a 5% yield. Therefore, the purpose of this study is to develop a new technique that reduces processing time and produces a higher yield.
Cell Adhesion to RGD-Alginate Is Modulated by Substrate Mechanics
Authors: Genes Nicholas G. , Silva Matthew D. , Sotak Christopher H. , Bonassar Lawrence J.
Published: November 2021

Alginate in solution is crosslinked in the presence of multivalent cations, making it a useful polymer for drug delivery and tissue engineering. The degree of crosslinking depends on the concentration (Rowley 2000) and chemical identity of the crosslinker (Seely 1974).
Noninvasive Estimation of Wall Strength Distribution in Human Abdominal Aortic Aneurysm
Authors: Wang David H. J. , Makaroun Michel S. , Vorp David A.
Published: November 2021

Abdominal aortic aneurysm (AAA) is an irreversible focal dilation of the infrarenal aorta. If left untreated, AAA will continue to expand and eventually rupture. Ruptured AAA is ranked as the 13th leading cause of death in the United States [1]. Accurate prediction of AAA rupture is critical for patient management. From a biomechanical point of view, this occurs when the stress in the aneurysm wall exceeds its strength. Therefore, reliable assessment of the risk of AAA rupture demands information on wall stress as well as wall strength.
A Structural Constitutive Model for Planar Collagenous Tissues That Integrates SALS-Derived Fiber Orientation Data
Authors: Sacks Michael S.
Published: November 2021

Structurally based constitutive models attempt to exploit the tissue composition and structure to avoid ambiguities in material characterization, and offer insight into the function, structure, and mechanics of tissue components. In the structural approach, the tissues total strain energy is assumed to be the sum of the individual fiber strain energies [1–3]. Although theoretically complete, the fiber architecture must be estimated from assumed distributions and “backed-out” from the mechanical data. Thus, fall realization of the structural approach is significantly limited without direct quantitative structural information to either validate structural model predictions or for direct implementation into the model. This limitation of the structural constitutive modeling approach motivated the development of the following structural constitutive model for planar collagenous tissue that directly incorporates the experimentally measured angular distribution of collagen fibers.
Response Analysis of Passive Human Knee Joint in Flexion Under Anterior-Posterior Loads
Authors: Moglo K. , Shirazi-Adl A.
Published: November 2021

The human knee joint is a multi-body complex system that experiences relatively large loads and displacements during normal daily activities. The joint stability is provided by its articular surfaces, menisci, ligaments and muscles. An injury to a component is expected to influence the joint normal kinematics/kinetics with liklihood to initiate/accelerate joint instability and degeneration. In this work, a validated nonlinear 3-D model of the human knee joint [1,2] is further refined and applied to the analysis of the tibiofemoral joint in passive flexion under 100N anterior or posterior horizontal preload. Attention is focused on the global (primary and coupled) motions, ligament forces and load transmission via articular surfaces. The effect of ligament initial strain on the response is also investigated.
Cell Motility in Microfabricated Models of the Tissue Microenvironment
Authors: Parker Kevin Kit , Ingber Donald E.
Published: November 2021

We conducted studies using micropatterned substrates to elucidate how cell shape and geometric confinement regulates the inter- and intracellular signaling pathways required for cell motility. When cells were cultured on individual cell-sized square adhesive islands coated with ECM, they extend to the edge of the island and assume a square shape. When these cells were stimulated with growth factors, they preferentially extended lamellipodia from the corners versus the sides. This process was mediated by myosin-generated isometric tension that induced tight spatial localization of Rac in the corners. When two or three capillary endothelial cells are constrained to a fibronectin (FN) island, coordinated cell migration results in stable rotation of the entire system about its center. Thus, the emergent pattern is due to the coordinated migration behavior of the cells. These observations suggest that ECM-induced mechanotransduction potentiates compartmentalized signaling pathways and the multicellular organization required of tissue morphogenesis.
Design of a Vibrating Fiber Display for a Wearable Low Vision Aid
Authors: Frank Samuel S. , Seibel Eric J.
Published: November 2021

There are over 14 million people in the United States who are classified as ‘low vision’, with visual acuity no better than 20/40 with best correction in their best eye. Of these, over 3 million are classified as ‘legally blind’, with visual acuity no better than 20/200 with the best correction in the better eye [1]. All of these people suffer from an inability to perform some or all of the simple daily tasks that the majority of ‘normal sighted’ people take for granted. These include, but are not limited to, navigating in- and outdoors; reading a newspaper or medicine bottles; recognizing faces. Helping as many of these people as possible perform these tasks is a daunting task, and requires an interactive system capable of extracting pertinent data from the environment, enhancing the data, and then presenting it to the user in a form that is well understood and relevant to the user’s task. A lightweight, small, inexpensive, and bright display device with a large field of view and high resolution is a key component of such a system.
Biomechanical Analysis of Pediatric Impact Head Injury: A 3-D Finite Element Modeling Approach
Authors: Kumaresan Srirangam , Sances Anthony , Hutchinson John , Friedman Keith
Published: November 2021

Infants and young children sustain head injury during falls and motor vehicle crashes. A better biomechanical understanding assists to mitigate the head injury in the pediatric population. A three-dimensional finite element model of an infant head was developed. The model included the cranial bone, sutures, fontanelles, brain and foramen magnum. The infant head was impacted with a stationary wall structure. Three types of walls (padded and unpadded flat walls, and unpadded cavity/edge wall) were used. The polypropylene and rigid materials were defined for the wall. Each analysis was conducted at an impact velocity of 6.7 and 8.9 m/sec. The cranial bone of the infant head sustained lower strain during the impact with the padded flat wall. The strain in the cranial bone increased considerably when the padding was removed. A further increase in the strain was observed during the impact with the unpadded cavity/edge wall. While the strain in the cranial bone was diffused under the padded flat wall impact, it was more concentrated under the unpadded cavity/edge wall impact condition.
A Novel Trileaflet Synthetic Heart Valve
Authors: Schoephoerster Richard T. , Gallocher Siobhain , Pinchuk Leonard , Kasyanov Vladimir A.
Published: November 2021

Heart valve prostheses have been used successfully since 1960 and generally result in improvement in the longevity and symptomatology of patients with valvular heart disease. However, NIH’s Working Group on Heart Valves reports that 10-year mortality rates still range from 30–55%, and that improvements in valve design are required to minimize thrombotic potential and structural degradation and to improve morbidity and mortality outcomes.
Flow Evaluation of a Compliant Coronary Artery Anastomosis Model
Authors: Anayiotos Andreas S. , Pedroso Pedro D. , Venugopalan Ramakrishna , Eleftheriou Evangelos , Advincula Maria A.
Published: November 2021

Coronary artery bypass grafting (CABG) is a common surgical procedure for coronary artery diseases or severe stenosis of the coronary arteries. It makes use of a peripheral vein (usually the saphenous vein of the leg) to form a conduit between the aorta and the coronary artery distal to the obstructive lesion. It is rapidly becoming the treatment of choice in cases where the vessel is more than 70% occluded or when angioplasty is not possible. However, a significant number of grafts subsequently fail due to acute thrombosis in the early post-operative period or to restenosis within months or years. Intimal thickening in the CABG anastomosis has been implicated as the major cause of restenosis and long-term graft failure. Several studies point to the interplay between non-uniform hemodynamics (including disturbed flows and recirculation zones), wall shear stress, and long particle residence time as possible etiologies. An important feature of the anastomosis geometry, is a bulge that forms at the veno-arterial junction. This sinus forms as a result of the stretching of the thin venous wall when the graft is exposed to aortic pressure conditions. The resultant sinus, and the impedance mismatch of the vein-artery connection, contribute to a complicated region of highly disturbed flow at the divider and may have a primary role in restenosis and final failure of the graft.
A New Approach for Dynamical Stable Criterion of Hot Strip Mills
Authors: Yoshida Mitsuhiro , Furumoto Hideaki , Yoshikawa Masashi , Morii Shigeki
Published: November 2021

The new approach of calculating dynamical behavior of hot strip mills is developed within linear response region. This method is based on steady state numerical calculation model using FEM for metal flow velocity distribution between rolls. By applying perturbation of roll displacements and velocity to 2 dimensional perturbed force damping and stiffness matrices are obtained by numerical calculation under certain reasonable boundary conditions. The dynamically stable limit conditions obtained from these matrices have a quite good agreement with experimental results. And it is made clear that friction coefficient plays an important roll for autonomous vibration of mills.
Age Effect Investigation on Postural Dynamic Responses of Human Body
Authors: Hoviattalab Maryam
Published: November 2021

Responses of human body were studied in two adult age groups. The healthy subjects with no records of falling down or occupation in a crowded and noisy environment were elected. Mean age was 24 and 71 yrs. in young and elderly groups, respectively. Four experimental tasks were presented to subjects. Two involving flat standing with open and closed eyes and two were involving imposed disturbances. Two optoelectronic camera systems were used to measure body motion. The extents of postural sway were determined by processing the recorded data from force plate. The results were compared, and also provided the basis for kinematics analysis of body segments. For dynamic analysis, we used 3-link biomechanical model on a stationary triangular foot. Results from dynamic analysis indicated that, (a) The angular displacement of body segments was larger in elderly group, especially at the trunk; (b) The visual system had a dramatic effect on balance control, and its omission along with onset of senescence, has progressive effect, i.e. increased the amplitude and frequency of body sway, up to 2.4 and 1.5 times, respectively; (c) It has been proved that, in response to sudden stimulation, body employs certain strategy for muscle contraction. “Maximum torque, occurs in ankle, and respectively diminishes in joints, on its course toward upper segments”. The point is well consistent with the literature in this contest.
Ergonomic Contribution to HGV Freight Handling Bay Entry Manoeuvring. Analysis of Lorry Driver Activity and Formation Needs
Authors: Hella Florence , Schouller Jean-François , Laville Valérie
Published: November 2021

A comprehensive analysis of lorry drivers performing freight handling bay reverse entry manoeuvres has been conducted for the purpose of proposing a driving aid system or undertaking action aimed at generating greater safety in such work situations. This analysis has been made possible through the use of a data acquisition unit and associated processing of video sequences, physical measures and observations (CAPTIV).

Description of driver manoeuvring procedures in relation with other task parameters made it possible to break up the handling bay entry into several phases and to understand at which moment perceptive difficulties requiring assistance do in fact occur.

A procedure specifically designed to compensate certain weaknesses in driving practice has been developed thanks to a participative approach. This new manoeuvring procedure encourages drivers to direct their gaze towards risk areas, which they did not spontaneously do before due to searching for spatial reference marks in other zones of the environment.
Study on Driver and Vehicle System With Lane-Tracking Control System Using Steering Torque Input
Authors: Nagai Masao , Yoshida Hidehisa , Shitamitsu Kiyotaka , Mouri Hiroshi
Published: November 2021

Although the vast majority of lane-tracking control methods rely on the steering wheel angle as the control input, a few studies have treated methods using the steering torque as the input. When operating vehicles especially at high speed, drivers typically do not grip the steering wheel tightly to prevent the angle of the steering wheel from veering off course.

This study proposes a new steering assist system for a driver not with the steering angle but the steering torque as the input and clarifies the characteristics and relative advantages of the two approaches. Then using a newly developed driving simulator, characteristics of human drivers and the lane-tracking system based on the steering torque control are investigated.