bluuebunny/crossref_metadata_2025 huggingface dataset:
Class A PBPs: It is time to rethink traditional paradigms
Authors: Straume Daniel , Piechowiak Katarzyna Wiaroslawa , Kjos Morten , Håvarstein Leiv Sigve
Published: March 2021

Until recently, class A penicillin‐binding proteins (aPBPs) were the only enzymes known to catalyze glycan chain polymerization from lipid II in bacteria. Hence, the discovery of two novel lipid II polymerases, FtsW and RodA, raises new questions and has consequently received a lot of attention from the research community. FtsW and RodA are essential and highly conserved members of the divisome and elongasome, respectively, and work in conjunction with their cognate class B PBPs (bPBPs) to synthesize the division septum and insert new peptidoglycan into the lateral cell wall. The identification of FtsW and RodA as peptidoglycan glycosyltransferases has raised questions regarding the role of aPBPs in peptidoglycan synthesis and fundamentally changed our understanding of the process. Despite their dethronement, aPBPs are essential in most bacteria. So, what is their function? In this review, we discuss recent progress in answering this question and present our own views on the topic.
Potato cyst nematodes Globodera rostochiensis and G. pallida
Authors: Price James A. , Coyne Danny , Blok Vivian C. , Jones John T.
Published: March 2021

Taxonomy

Phylum Nematoda; class Chromadorea; order Rhabditida; suborder Tylenchina; infraorder Tylenchomorpha; superfamily Tylenchoidea; family Heteroderidae; subfamily Heteroderinae; Genus Globodera.

Biology

Potato cyst nematodes (PCN) are biotrophic, sedentary endoparasitic nematodes. Invasive (second) stage juveniles (J2) hatch from eggs in response to the presence of host root exudates and subsequently locate and invade the host. The nematodes induce the formation of a large, multinucleate syncytium in host roots, formed by fusion of up to 300 root cell protoplasts. The nematodes rely on this single syncytium for the nutrients required to develop through a further three moults to the adult male or female stage. This extended period of biotrophy—between 4 and 6 weeks in total—is almost unparalleled in plant–pathogen interactions. Females remain at the root while adult males revert to the vermiform body plan of the J2 and leave the root to locate and fertilize the female nematodes. The female body forms a cyst that contains the next generation of eggs.

Host range

The host range of PCN is limited to plants of the Solanaceae family. While the most economically important hosts are potato (Solanum tuberosum), tomato (Solanum lycopersicum), and aubergine (Solanum melongena), over 170 species of Solanaceae are thought to be potential hosts for PCN (Sullivan et al., 2007).

Disease symptoms

Symptoms are similar to those associated with nutrient deficiency, such as stunted growth, yellowing of leaves and reduced yields. This absence of specific symptoms reduces awareness of the disease among growers.

Disease control

Resistance genes (where available in suitable cultivars), application of nematicides, crop rotation. Great effort is put into reducing the spread of PCN through quarantine measures and use of certified seed stocks.

Useful websites

Genomic information for PCN is accessible through WormBase ParaSite.
Identifying varieties of nationalism: A critique of a purely inductive approach
Authors: Eger Maureen A , Hjerm Mikael
Published: March 2021

Most theoretical and empirical approaches to nationalism not only distinguish between ethnic and civic notions of national belonging but also differentiate national identity from national hubris, pride, and attachment. In this research note, we examine recently published research on nationalist sentiments in the United States that takes a different approach. The study in question, ‘Varieties of American Popular Nationalism' by Bonikowski and DiMaggio (2016), has already become quite influential in the field and has the potential to change how we conceptualise and operationalise attitudes about the nation. In this research note, we revisit its analytical strategy and exploratory methods. We ask two questions. First, does this study allow us to draw conclusions about American nationalism? To answer this, we replicate the original model and then execute additional postestimation analyses, whose results undermine the study's main conclusions. Second, we investigate whether judicious revisions to the study's model generate results that would lead us to the article's same conclusions. The 385 additional models lend no support. Based on this evidence, we argue that the original study's conclusions stem from a misinterpretation of its latent class analysis (LCA), as our own analyses demonstrate that there is no empirical basis for its claims.
The knowledge and practice of maintaining the patency of arterial catheters
Authors: Xiao Yanyan , Wang Yi , Yuan Cui , Wang Fang
Published: March 2021

Background

Maintaining the patency of arterial catheters—routinely inserted in critically ill patients in intensive care units (ICUs)—is essential for obtaining physiological measurements and enabling blood sampling.

Aim

This study aims to evaluate current ICU nurse knowledge and practice of maintaining the patency of arterial catheters and explore the factors that influence nurses' knowledge level.

Design

This was a cross‐sectional survey conducted in China.

Methods

This research was conducted in 20 tertiary hospitals in Beijing, China between March and June 2020. The data were collected by electronic questionnaire, which was designed in accordance with the literature and consisted of 28 questions. Descriptive and inferential statistics were used to analyse the data.

Results

A total of 576 completed questionnaires were returned. The mean score of nurses' knowledges was 3.66 ± 1.35, which is a moderate level. There was a statistically significant difference between the mean scores of nurses with different professional titles and work experiences (mean 3.58 vs 4.04/7; mean 3.50 vs 3.58 vs 3.94/7). Considering ICU nurses' practice of maintaining the patency of arterial catheters, 376(65.3%)nurses replaced the pressure transducer as per the manual, and 347 (60.2%) nurses zeroed the pressure transducer once per shift. More than 90% ICU nurses aligned the transducer with the heart surface marker during zeroing procedures. Furthermore, 79.9% of nurses performed fast‐flush tests routinely, 459 (85.9%) nurses flushed the arterial catheter routinely, and 80% of nurses evaluated the patency of the arterial catheter every shift.

Conclusions

This study found that the practices of ICU nurses varied, and their knowledge of how to maintain the patency of arterial catheters was moderate and could be improved. ICU nurses should be trained effectively to develop a unified standard of arterial catheter management.

Relevance to clinical practice

Training programmes on arterial catheter management for ICU nurses are essential for improving knowledge and practice.
Kinematic Characteristics and Biomechanical Changes of Lower Lumbar Facet Joints Under Different Loads
Authors: Song Yang , Wen Wang‐qiang , Xu Jin , Zhang Ze‐pei , Han Ye , Li Ke‐peng , Wang Xiao‐dong , Xu Hao‐xiang , Liu Jianan , Miao Jun
Published: March 2021

Objective

To explore the kinematic biomechanical changes and symmetry in the left and right sides of the facet joints of lumbar spine segments under different functional loads.

Methods

Participants (n = 10) performing standing flexion and extension movements were scanned using computed tomography (CT) and dual fluoroscopy imagine system. Instantaneous images of the L3–S1 vertebrae were captured, and by matching a three‐dimensional CT model with contours from dual fluoroscopy images, in vivo facet joint movements were reproduced and analyzed. Translations and rotations of lumbar vertebral (L3 and L4) facet joints of data were compared for different loads (0, 5, 10 kg). The participants performed flexion and extension movements in different weight‐bearing states, the translations and angles changes were calculated respectively.

Results

From standing to extension, there were no statistical differences in rotation angles for the facet joint processes of different vertebral segment levels under different weight loads (P > 0.05). Mediolateral axis and cranio‐caudal translations under different weight loads were not statistically different for vertebral segment levels (P > 0.05). Anteroposterior translations for L3 (1.4 ± 0.1 mm) were greater than those for L4 (1.0 ± 0.1 mm) under the different load conditions (P = 0.04). Bilaterally, mediolateral, anteroposterior, and cranio‐caudal translations of the facet joints under different weights (0, 10 kg) for each segment level (L3 and L4) were symmetric (P > 0.05). From flexion to standing, there were no statistical differences in rotation angles for different weights (0, 5, 10 kg) for each level (L3 and L4) (P > 0.05). There were no statistical differences between mediolateral, anteroposterior, and cranio‐caudal translations at each segment level (L3 and L4) under different loads (P > 0.05). Under the condition of no weight (0 kg), L3 mediolateral translations on the left side (1.7 ± 1.6 mm) were significantly greater (P = 0.03) than those on the right side (1.6 ± 1.6 mm). Left side (1.0 ± 0.7 mm) L4 mediolateral translations were significantly smaller (P = 0.03) than those on the right side (1.1 ± 0.7 mm). There were no statistical differences between different weights for either anteroposterior and cranio‐caudal translations (P > 0.05). There were no statistical differences for mediolateral, anteroposterior, and cranio‐caudal translations for 10 kg (P > 0.05).

Conclusion

Lumbar spine facet joint kinematics did not change significantly with increased loads. Anteroposterior translations for L3 were greater than those for L4 of the vertebral segments are related to the coronal facet joint surface. Changes in facet surface symmetry indicates that the biomechanical pattern between facet joints may change.
Public works programs and crime: Evidence for El Salvador
Authors: Acosta Pablo , Monsalve Montiel Emma
Published: March 2021

Most evaluations of public works programs in developing countries study their effects on poverty reduction and other labor market outcomes (job creation, earnings, and participation). However, very few look at other collateral effects, such as the incidence of violence. Between 2009 and 2014, El Salvador implemented the Temporary Income Support Program (PATI), which aimed at guaranteeing a temporary minimum level of income to extremely poor urban families for 6 months, as well as providing beneficiaries with experience in social and productive activities at the municipal level. Making use of a panel data set at the municipal level for 2007–2014, with monthly data on different types of crime rates and social program benefits by municipalities, this paper assesses the effects of the program on crime rates in municipalities in El Salvador. There are several possible channels through which the PATI can affect crime. Since the program is associated with cash transfers to beneficiaries, a decrease in economically motivated crimes is expected (income effect). But since the program enforces work requirements and community participation, this could generate a negative impact on crime, because the beneficiaries will have less time to commit crime and because of community deterrence effects. Overall, the paper finds a robust and significant negative impact of the PATI on most types of crimes in the municipalities with the intervention. Moreover, the negative effects of the program on some types of crime rates hold several years after participation. The positive spillover effects for municipalities hold within a radius of 50 km.
Use of Fracking Information Disclosure Policies to Reduce Uncertainty in Risk‐Based Decisions
Authors: Lonnquist Sean , Gallagher Deborah
Published: March 2021

The hydraulic fracturing (fracking) boom has outpaced both our understanding of its potential impacts on human health and the environment, as well as the legal and regulatory frameworks in place to govern it. We conducted interviews in Pennsylvania with individuals living in communities affected by fracking to examine how residents perceive the laws and regulations that are in place to protect them from its risks. We found that residents felt that they lacked access to sufficiently comprehensive and comprehensible information about the potential risks that fracking poses. We then drew from scholarship on the use of information disclosure as a regulatory tool to discuss the need for increased information transparency in the fracking context, and proposed several policy interventions that could ease the information asymmetry experienced by residents in these communities.
COVID‐19: Risk Factors Associated with Infectivity and Severity
Authors: Fadl Nahla , Ali Esraa , Salem Tamer Z.
Published: March 2021

COVID‐19 is highly transmissible; however, its severity varies from one individual to another. Variability among different isolates of the virus and among its receptor (ACE2) may contribute to this severity, but comorbidity plays a major role on disease prognosis. Many comorbidities have been reported to be associated with severe COVID‐19 patients. We have collected data from retrospective studies which include clinical and epidemiological features of patients and categorize them into severe/mild, ICU/non‐ICU and survivors/dead patients. In this review, we give an update about SARS‐CoV‐2 structure with emphasis on the possible reasons for the severity of the virus in patients. We also collected information and patients’ data to highlight the relation between COVID‐19 patients and comorbidities.
Prospective randomized controlled blinded clinical trial evaluating biomarkers of acute kidney injury following 6% hydroxyethyl starch 130/0.4 or Hartmann's solution in dogs
Authors: Boyd Corrin J. , Sharp Claire R. , Claus Melissa A. , Raisis Anthea L. , Hosgood Giselle , Smart Lisa
Published: March 2021

Objective: To evaluate the effect of 6% hydroxyethyl starch (HES) 130/0.4, compared with a Hartmann's solution control (CRYST), on urine biomarkers of acute kidney injury (AKI) in dogs prescribed a fluid bolus.

Design: Randomized, controlled, blinded clinical trial January 2018 to February 2019.

Setting: University teaching hospital.

Animals: Forty client‐owned dogs.

Interventions: Dogs prescribed a fluid bolus were randomized to receive at least 10 mL/kg of HES or CRYST with clinicians and investigators blinded to fluid type. Study fluid was used for further boluses as required in the following 24 hours, to a limit of 40 mL/kg total, after which fluid administration was open‐label.

Measurements and Main Results: Urine was collected prior to and 6, 12, and 24 hours after the first study fluid bolus. Urine concentrations of AKI biomarkers: neutrophil gelatinase‐associated lipocalin (NGAL), cystatin C, kidney injury molecule‐1 (KIM), clusterin, and osteopontin were measured using a magnetic bead multiplexed assay. Osmolality‐indexed biomarker concentrations were compared between groups over time with linear mixed‐effects models, with P < 0.05 considered significant. The mean volume of study fluid administered was not significantly different between groups (HES: 23.1 mL/kg, CRYST: 25.9 mL/kg; P = 0.47, t‐test). There were no significant differences between groups in change over time of osmolality‐indexed urine concentrations of NGAL (P = 0.91), cystatin C (P = 0.95), KIM (P = 0.77), clusterin (P = 0.63), or osteopontin (P = 0.91). The maximum Veterinary Acute Kidney Injury (VAKI) score up to 7 days during hospitalization (P = 1.0) and in‐hospital mortality (P = 0.49) were not significantly different between groups, as compared by Fisher's exact test.

Conclusions: There were no differences in change over time of urine AKI biomarkers in dogs treated with 10 – 40 mL/kg HES or CRYST over 24 hours. Larger clinical trials with patient‐centered outcomes are required to investigate the safety of HES in dogs.
Critical Shear Stress of Plates Above the Proportional Limit
Authors: Gerard George
Published: March 2021

The secant-modulus method previously used for determining critical compressive stresses above the proportional limit has been extended for use in determining critical shear stresses above the proportional limit. The method was confirmed by an experimental program designed to check the use of the shear-secant modulus in the critical-shear-stress equation. Nondimensional critical-shear-stress design curves are presented for use with aluminum alloys.
Effect of a Concentric Reinforcing Ring on Stiffness and Strength of a Circular Plate
Authors: Nash W. A.
Published: March 2021

In this study of a fixed-edge circular plate subjected to uniform normal pressure (such as is commonly used on ends of thin-walled cylindrical pressure vessels), it is shown that the maximum vertical deflection, the maximum radial stress, and the maximum tangential stress may all be reduced by reinforcing the plate with a concentric ring.
On the Aerodynamic Design of Axial-Flow Compressors and Turbines
Authors: Vazsonyi Andrew
Published: March 2021

In this paper a theoretical method is presented to determine the flow of a perfect (frictionless, incompressible) fluid across a cascade built up of arbitrary airfoils. The presentation refers to compressor blading but is immediately applicable to turbine blading. The lift-coefficient curve as a function of angle of attack (or deflection-angle curve) of an arbitrary cascade can be determined in about 10 man-hours. The complete investigation of all possible cascades built up of a given airfoil (any solidity and any stagger) requires about 60 man-hours. The procedure is graphical and standardized to the extent that no mathematical knowledge is required of the computer. Agreement between theory and tests is excellent (see Figs. 19 and 20). An extension of the method is indicated whereby the detailed pressure and velocity distribution of the flow can be obtained.
Stress-Strain Relations for Finite Elastoplastic Deformations
Authors: Dorn J. E. , Latter A. J.
Published: March 2021

The strains accompanying elastoplastic deformations are frequently so large that the simplified equations of the small-strain theory are invalid. Although several ways of describing finite strains are known (1), they are not readily adaptable to stress-strain analyses in elastoplastic materials. One of the difficulties arises from the failure of the laws of addition when the strains are defined in the conventional way. Another difficulty arises from the observations that the infinitesimal plastic strains, and not the finite strains, are related to the stresses. The accompanying analysis, which attempts to surmount these difficulties, is an extension of methods originally described in a paper on plastic flow in metals (2), to include elastic as well as plastic deformations.
A Law of Work-Hardening
Authors: Freudenthal A. M. , Reiner M.
Published: March 2021

Based on the “blocking” theory of the strength of a poly-crystalline metal, a law of work-hardening is derived and checked experimentally on mild steel deformed by wire-drawing up to a deformation of 4.6 in the logarithmic measure. The law correlates the recoverable strain work with the total work of deformation in a series of exponential functions, the number of which corresponds to the number of sizes of crystal grains present in the annealed state.
The Partitioning of Matrices in Structural Analysis
Authors: Benscoter S. U.
Published: March 2021

The practical value of the partitioning of matrices in structural analysis is illustrated with the solution of two multicell box beams in torsion. The desirability of partitioning a matrix is determined from a simple principle relating to the pattern of the matrix. Typical patterns of matrices that are readily inverted are noted and employed in the solution by matrix partitioning.
Large Deformations of an Elastic Solid
Authors: Chilton E. G.
Published: March 2021

Hencky’s stress-strain relation for large deformations of a rubberlike material is reviewed. It is then applied to the specific cases of pure tension, compression, bending, shear, and torsion. Each of these cases is verified experimentally on samples made from natural rubber. Particular emphasis is placed on the shear and torsion analysis because of its importance to practical applications.
Hybrid Brayton Multi-Stage Concentrated Solar Power Plant Energy and Exergy Performance Study
Authors: Moreno-Gamboa Faustino , Nieto-Londoño César
Published: March 2021

Hybrid Brayton concentrated solar power (CSP) plants have been gaining attention in the last decade upon many advantages regarding the use of traditional generation technologies combined with renewable energy sources. However, some technical and economic issues must be solved to allow its widespread use. Research and development efforts are deemed essential to the study of factors that constrain cycle performance looking to increase its efficiency, reducing fuel consumption, and decreasing emissions. This study presents the performance evaluation of a hybrid multi-stage CSP plant considering specific environmental conditions to attain the factor that constrains its optimal performance. Overall energy and exergy plant efficiencies are analyzed, considering an arbitrary number of stages. For instance, a double compression expansion hybrid CSP plant shows the overall energy efficiency of 32% larger, a 30% higher exergy efficiency, and a fuel conversion rate around 18% larger when compared with a single-stage CSP plant.
Computation of Acoustic Velocity of Natural Gases With an Alternative Heat Capacity Ratio Equation and Application to Seismic Modeling
Authors: Carvalho Romulo , Moraes Fernando
Published: March 2021

We investigate three formulations for computing acoustic velocity of natural gas and derive an equation for the heat capacity ratio, which plays a central role in these formulations. The first formulation is a compilation of fundamental equations available in the engineering literature, referred to as the DASH formulation. The second formulation is a development from the first, in which we use the derived equation for the heat capacity ratio (modified DASH). The third formulation is a mainstream method implemented in Geoscience (BW formulation). All three formulations stem from virial Equations of State that take preponderance in the exploration stage, when the detailed fluid composition is unknown and compositional methods are frequently inapplicable. We test the formulations on an extensive experimental data set of acoustic velocity of natural gases and compare the resulting accuracies. Both DASH and modified DASH formulations provide significantly higher accuracy when compared to the BW formulation. Additionally, the modified DASH, as we derive in this work, has the highest accuracy at pressures above 7000 psi, a condition typically encountered in the Brazilian pre-salt reservoirs. In a final step, we investigate how these different formulations and corresponding accuracies in velocity computation may affect seismic modeling, using a single interface model between a dense gas reservoir and a sealing rock. A direct comparison of amplitude versus offset modeling using our modified DASH formulation and the BW formulation shows up to 50% difference in amplitude calculation in a sensitivity exercise, especially at the longer offsets and higher pressures.
Enhancing the Solidification Between Mud Cake and Wall Rock for Cementing Applications: Experimental Investigation and Mechanisms
Authors: Bai Xiaodong , Xu Yuqian , Zhang Xuepeng , Yong Xuemei , Ning Tao
Published: March 2021

In conventional cementing operations, the mud cake on the well wall cannot be completely removed， which can easily lead to annular channeling. In order to reduce the influence of loose and fragile mud cake on cementing, a kind of mud cake curing agent is used to effectively improve the curing quality of mud cake and rock. In this article, the mud cake compressive strength are tested by compression-testing machine. The samples are analyzed using X-ray diffractometer (XRD), scanning electron microscopy (SEM), and energy disperse spectroscopy (EDS). The results showed that the cementing agent can significantly improve the cementation strength between mud cake and wall rock. A variety of hydration products were resulted such as CaAl2Si2O8 · 4H2O, Ca(SiO4)2(OH)2, and Mg4Al2(OH)14 · 3H2O, as revealed from the XRD analysis. In addition, it was found that the formation of hydration products is the main reason for the increase of cementation strength. The flocculent inclusions filled with solid particles are formed on the solid particles of the mud cake, which makes an integrated cementation at the interface between mud cake and wall rock. A large amount of cations including Ca2+, Mg2+, and Al3+ are collected at the cementation interface, which is the basic condition for various hydration reactions and helps to enhance the cementation strength of the mud cake and rock interface.
Foaming Properties and Foam Structure of Produced Liquid in Alkali/Surfactant/Polymer Flooding Production
Authors: Wang Zhihua , Liu Xiaoyu , Luo Huan , Peng Baoliang , Sun Xitong , Liu Yang , Rui Zhenhua
Published: March 2021

Alkali/surfactant/polymer (ASP) flooding process is proven to be vitally effective for enhancing oil recovery (EOR) in the oil industry. However, foaming behavior is generated by the breakthrough of chemical agents in the produced liquid and is increasingly concerned as a terrible problem during production. A set of experiments were recently performed to investigate the effects of foaming properties of ASP flooding produced liquid. The factors affecting foaming capacity and foam stabilization were discussed, and the differences in foaming properties of produced liquid between the strong base and weak base ASP flooding were first compared. The results indicated that in addition to temperature and pressure, the concentrations of chemical agents in the produced liquid were responsible for the foaming properties and foam stabilization. The foaming capacity could enhance 3–7% at 45 °C compared with a lower temperature of 35 °C. The average comprehensive index of the foam could increase from 2.2 × 105 at 29 psi to 2.5× 105 at 73 psi. The regularity of Plateau borders was highlighted at higher pH and surfactant concentration and thus facilitated the foam stabilization. The liquid film thickened and its shape expanded to the state of maintaining foam stabilization with the increase of polymer concentration. Furthermore, the foaming behavior of produced liquid in strong base ASP flooding production is much-more troublesome than that in weak base ASP flooding production. This study is significant in that it further supports the development of efficient treatment technology for produced liquid in the oilfield.
A Predictive Frontal and Oblique Collision Mitigation System for Autonomous Vehicles
Authors: Sun Chuanyang , Eskandarian Azim
Published: March 2021

This paper presents a collision mitigation system for an unavoidable collision with an arbitrary oncoming obstacle vehicle. A set of candidate trajectories are generated by a model-based method and a hierarchical efficient collision-checking method is applied to check the potential collision between the predicted trajectory of the obstacle vehicle and the candidate trajectories of the ego vehicle. A novel method based on the vehicle polygon is applied to identify the specific impact location of the vehicle body. The predicted Delta-V and the identified impact location are combined to evaluate the outcome severity of the upcoming accident for each candidate trajectory. Based on the evaluated results, a path with the least damage would be selected and executed to mitigate the collision. Simulation and analysis are performed to investigate the performance of the presented system in a high-speed scenario of a detailed vehicle model.
Experimental Study of Thermal Management and Enhancement of Adsorption-Based Onboard Hydrogen Storage System
Authors: Wang Hailei , Miller Daniel C.
Published: March 2021

Although hydrogen has one of the highest specific energies, its energy density in terms of volume is very poor compared to liquid fuels. Thus, to achieve attractive energy density for hydrogen, either high-pressure compression or a storage method is needed. For onboard (vehicles) hydrogen storage, up to 700 bars are needed for commercial fuel cell vehicles. This creates extreme requirements for material strength and thus safety concerns. A new metal-organic framework 5 (MOF-5) was selected as the adsorbent for H2 storage, as it provides promising storage capacity and is commercially available. Under the same H2 storage capacity and tank volume, the adsorption system is expected several folds reduction in pressure. Under the current study, a unique thermal management design using Modular Adsorbing Tank Insert (MATI) is paired with conduction-enhanced compressed MOF-5 beds. Compared to bare beds without conduction enhancement, all beds with conduction enhancement using either aluminum pins or expanded natural graphite (ENG) have shown various levels of improvement on bed thermal response, which can potentially help expedite system charge and discharge cycle times for real applications.
A Novel Approach Investigating the Remaining Useful Life Predication of Retired Power Lithium-Ion Batteries Using Genetic Programming Method
Authors: Qi Dongfeng , Li Congbo , Wang Ningbo , Huang Mingli , Hu Zengming , Li Wei
Published: March 2021

Electric vehicles (EVs) have been widely cherished by consumers in recent years. However, as the number of EVs continues to increase, the number of retired power batteries will also increase, especially retired power lithium-ion batteries (LIBs), which will cause serious energy waste. To reuse sufficiently retired power LIBs, we studied the remaining useful life (RUL) of the power LIBs after retirement, so that the battery can be used in different usage scenarios, such as electric bicycles, grid energy storage, and communication base stations. The study first considers the inconsistency of the internal resistance and capacity of the LIBs pack and uses the battery available energy to predict the RUL of the retired power LIBs. Then, we further use the genetic programming (GP) method to predict the RUL of retired power LIBs. The case study shows the prediction accuracy of GP is better than response surface methodology (RSM), Kriging, and radial basis function (RBF) surrogate model. When the LIBs cycles are 100, 110, 120, and 130, the GP model prediction is relatively accurate and the minimum prediction error is only 5.26%.
Tribological Performances of Modified Babbitt Alloy Under Different Sliding Modes
Authors: Ni Yuquan , Zhang Hui , Dong Guangneng
Published: March 2021

This paper aims to improve wear resistance of bare Babbitt modified by CuLa and evaluates the effect of different sliding modes on tribological properties of bare Babbitt, Babbitt modified by 0.5 wt% CuLa (marked by mbabbitt-1), and Babbitt modified by 1 wt% CuLa (marked by mbabbitt-2). First, bare Babbitt was modified with different contents of CuLa. The microstructure, microhardness, and wettability of Babbitt were tested and studied. Then, the tribological properties of bare Babbitt, mBabbitt-1, and mBabbitt-2 were conducted by the reciprocating mode and unidirectional mode under the lubricated condition. The results showed that the SnSb grain of the modified Babbitt was refined and uniformly distributed. The microhardness of mBabbitt-1 was higher than that of bare Babbitt and mBabbitt-2. Compared with bare Babbitt, the wettability of mBabbitt-1 and mBabbitt-2 was improved. Anti-friction and wear resistance of specimens under the reciprocating mode were better than that of specimens under the unidirectional mode, which was attributed to low strain and equivalent stress of bare Babbitt under the reciprocating mode. Moreover, anti-wear of bare Babbitt was improved by adding CuLa due to refined grain and high microhardness.
Investigation of Declarative Feature Modeling
Authors: Shah Jami J. , Ali Ahsan , Rogers Mary T.
Published: March 2021

Features are composed of not only geometric entities, but also intrinsic/extrinsic geometric relations, hierarchical relations, size and location limits, and other higher level attributes. In the declarative approach, a feature is defined as a set of constraints applied to geometric entities or primitive volumes. Declarative modeling is facilitated by building blocks which enable constraint specification between feature entities. This paper will describe the methodology for the development of feature building blocks using standardized sets of geometric constraints, which can be used in the construction of graph based representation of features that are implementation independent. The declarative approach presented here takes advantage of two types of generic systems available commercially: geometric modeling core packages and constraint solvers. A graphical user-interface is also described for defining and archiving generic features in a library.
Identification of General Protrusion and Depression Features
Authors: Clark D. E. R. , Corney J.
Published: March 2021

This paper describes a robust method for identifying general protrusions and depressions on 2½D bodies. The results of applying the algorithm to a simple component are presented and their significance discussed. In the course of this discussion it is shown how many types of “open depression features”, such as slots and open pockets, could be identified as a subsequent step to the location of the protrusions on a body.
Incremental Recognition of Machining Features
Authors: Han JungHyun , Requicha Aristides A. G.
Published: March 2021

Manufacturing analysis programs that operate in a batch mode are inappropriate for a concurrent engineering environment, in which designers interact with an evolving product model and require rapid feedback on the manufacturing implications of design actions. This paper discusses a design for an automatic recognizer of machining features that operates incrementally, updating its results efficiently after each design step. The Incremental Feature Finder (IFF) builds upon an earlier, batch recognizer called OOFF, developed at USC in the late 1980s. IFF exploits spatial locality and feature dependency information, stored in a Truth Maintenance System, to improve its performance.
A Collaborative Process Planning and Scheduling System
Authors: Kempenaers Jan , Pinte Jos , Detand Jan , Kruth Jean-Pierre
Published: March 2021

Traditionally, process planning and scheduling have been rather separate activities within a company. Nowadays, the need for more flexible production and shorter production lead times urges for a close collaboration between these activities as a first step towards simultaneous engineering.

This article describes the results of the ongoing ESPRIT Project COMPLAN, which aims at the implementation of an integrated automatic process planning and scheduling system based on the concept of non-linear process plans.

Additionally to the use of NLPP for flexible load balancing and re-active rescheduling, a new collaborative approach is presented that is based on production constraints as a means to realise a feedback from scheduling to process planning. A process planning kernel is described that integrates this concept of production constraints.
Virtual Prototyping: An Approach Using VR-Techniques
Authors: Dai Fan , Göbel Martin
Published: March 2021

Rapid prototyping is becoming a key factor in speeding up the product development process. This paper presents a concept of electronic prototyping called virtual prototyping. The idea is to integrate product modelling with computer simulation, realistic visualization and virtual reality techniques to make the product data model a virtual prototype. In contrast to physical prototypes, a virtual prototype is made very fast, can be manipulated and modified directly and the data is reusable. A preliminary implementation of our concept is available at IGD.
Towards Fewer Design Failures
Authors: Yao Zhihui , Johnson Aylmer L.
Published: March 2021

Many designs fail because one or more checks are not done, or are done too late during the design process. A functional modelling system is presented, which provides systematic design checking at early design phases by means of constraint satisfaction. However, problems can occur if the design to be checked involves too many constraints.

This paper presents some extended research, which establishes a knowledge hierarchy for managing the mathematical constraints, so that the computer can process large designs. A case study of fastening joint design using this hierarchy is discussed.
Estimation of Error in Acoustic Analysis
Authors: Tetambe Ravi P. , Rajakumar C.
Published: March 2021

Application of error estimation in acoustical analysis is shown. Based on the Zienkiewicz-Zhu1 error estimator for stress analysis, a procedure for predicting the error in pressure distribution computed from a frequency domain analysis of acoustic cavities is outlined. Examples are presented to illustrate the usefulness of the error estimator in adaptively meshing the acoustic domain to minimize the error at different excitation frequencies.
Complex Modal Analysis of a Flat Belt Pulley System With Belt Damping and Coulomb Damped Tensioner
Authors: Kraver Theodore C. , Fan G. William , Shah Jami
Published: March 2021

The effects of damping on the rotational vibratory solution of a multiple pulley-flat elastomeric belt system with rotary tensioner is developed. Visco-elastic belt and coulomb tensioner arm damping are included. Belt span tension amplitude can also be determined. A complex modal procedure is developed to provide a straight forward way to solve for both the under-damped and over-damped cases. This complex modal procedure for the high-order non-symmetrical dynamic system solution was used to allow future extension to the non-symmetric rotational model of pulley wobble and transverse belt vibration coupling. The modal solution provides the rapid analysis over a spectrum of frequencies and saves significant time when compared to numerical integration techniques. Experimental results from the literature for a seven pulley test rig supports the complex modal solution in this paper. Analyses predict significant effect of belt damping on vibration amplitudes but minor effect from tensioner spring rate and coulomb damping.
CAD and Optimization of Helical Torsion Springs
Authors: Metwalli Sayed M. , Radwan M. Alaa , Elmeligy Abdel Aziz M.
Published: March 2021

The convensional procedure of helical torsion spring design is an iterative process because of large number of requirements and relations that are to be attained once at a time. The design parameters are varied at random until the spring design satisfies performance requirements.

A CAD of the spring for minimum weight is formulated with and without the variation of the maximum normal stress with the wire diameter. The CAD program solves by employing the method of Lagrange-Multipliers. The optimal parameters, in a closed form are obtained, normalized and plotted. These explicit relations of design variables allow direct evaluation of optimal design objective and hence, an absolute optimum could be achieved.

The comparison of optimum results with those previously published, shows a pronounced achievement in the reduction of torsion spring weight.
Hypermedia Programs for Mechanical Engineering
Authors: Hight Timothy K. , Hornberger Lee E. , Lawrence Elizabeth , Gawlowski Matthew W.
Published: March 2021

Engineers need to absorb and learn large amounts of new technical information. Effective methods of receiving this information are needed. Hypermedia stacks are one emerging avenue for information transmittal. This paper discusses two programs that have been created to address two distinct requirements for information transmittal — description of new technology in an easily accessible form, and guiding novices in developing skills and gaining insights in solving a particular type of problem. The first program was developed using a HyperCard stack and a Macintosh computer and describes current techniques available for rapid prototyping. Professional engineers and engineering students are largely unaware of these technologies because information on the subject is new. The second program is being developed using ToolBook under Windows and deals with the problem of sizing an idler shaft under given loads and operating conditions. This is a standard type of problem that might be given in a junior level machine design course. It draws on knowledge from statics and strength of materials and so acts as a review of fundamentals as well as a test of deeper understanding. This second program is at an earlier stage of development.
SCI Lamp for Multimedia Applications
Authors: Li Qiang
Published: March 2021

Multimedia technology has become widely available and it has tremendous potential. As computers getting faster every day, multimedia applications are reaching new ground constantly. However, a fundamental problem of multimedia systems is the interprocessor/intermachine communication speed. In this paper, we introduce a platform based on the Scalable Coherent Interface (SCI, ANSI/IEEE std 1596). The system can be physically distributed but logically closely coupled. All processors/machines in an SCI system shared physical memory and cache coherence is maintained even among remote processors. The interprocessor communication bandwidth can be as high as 1 Gbyte/sec. We will discuss the features of SCI-based systems when multimedia application is considered.
Robustness Consideration in Modelling a Prototype by Quality Engineering
Authors: Li Chang-Chung , Sheu Tsong-Shin , Lee Yu-Cheng
Published: March 2021

Traditional model theory uses dimensional analysis and similarity to obtain design conditions for model construction and then uses prediction equations to predict the performance of a prototype. No consideration of quality is involved. In this paper, through model theory, we illustrate with examples that a high quality prototype can be obtained by quality engineering using robust design.
Set-Based Concurrent Engineering and Toyota
Authors: Ward Allen C. , Liker Jeffrey K. , Sobek Durward K. , Cristiano John J.
Published: March 2021

This article presents a paradigm for concurrent or simultaneous design. The paradigm explains apparent paradoxes in the development strategies of the Toyota Motor Company. Evidence from various interviews in the U.S. and Japanese automakers and automotive suppliers is presented, including two in-depth case studies. The article concludes with a discussion of the potential benefits of this paradigm.
Conflict Resolution in Concurrent Engineering Processes
Authors: Kannapan Srikanth M. , Taylor Dean L.
Published: March 2021

Naive interpretations of concurrent engineering may expect extreme parallelization of tasks and simultaneous accommodation of multiple perspectives. In fact, from our efforts at modeling tasks in a MEMS (Micro-Electro-Mechanical Systems) pressure sensor design project, it appears that data dependencies due to the structure of tasks and the product itself result in scenarios of decision and action that must be carefully coordinated. This paper refines a previously described information model for defining evolving contexts of product model aspects and team member perspectives, with software agents acting on behalf of team members to execute tasks. The pressure sensor design project is analyzed in the framework of the information model. A scenario of decision and action for design of the pressure sensor is modeled as a design process plan. Conflict on a shared parameter occurs as a consequence of introducing some parallelism between the capacitance and deflection agents in the process. We present a technique for negotiating such conflicts by definition and propagation of utility functions on decision parameters and axiomatic negotiation.
A Study of the Information Handling Behavior of Designers During Conceptual Design
Authors: Baya Vinod , Leifer Larry J.
Published: March 2021

The research reported in this paper examines the design process from an informational perspective. The study is based on the premise that there is a need to understand and formalize the information generating, accessing and analyzing behavior of designers in order to build tools and methods which can be smoothly integrated with their technical and social work environment. Results from an experimental study, conducted using the verbal protocol method, are discussed. A measure for the amount of information designers handle has been explored. A framework for analyzing the information handling behavior of designers is also presented.
A Generic Mechanism Model for Computer-Aided Conceptual Design of Machines
Authors: van der Werff K. , Zhang W. J. , Crone H. A.
Published: March 2021

This paper presents an application data model for the representation of conceptual structures of mechanisms. The main features in building this model are (1) to use semantic database modelling approaches and (2) to have a generic model. The model has been used in developing a software environment system for integrated design and manufacturing of mechanisms. Both conceptual design and implementation issues concerning this model are discussed. The system intelligence can be increased via a proper application data model. In particular, the concepts handling raw data and handling different views from the same object are clarified. The necessity and the technique to support them are discussed both in a general sense and in our mechanism data model.
Designing a Design Degree in Engineering
Authors: Bieniawski Z. T.
Published: March 2021

At a time when engineering education comes under increasing scrutiny and criticism, and in the face of a new accreditation requirement for a design-integrated curriculum extending over the full four years of studies in engineering, a proposal is made for a B. S. degree in Design Engineering. It is shown that there is considerable demand for sound knowledge of design fundamentals and for broad understanding of the engineering design process, and that such a degree would serve the needs of engineering graduates of the next century and would be welcomed by industry. The paper demonstrates an innovative concept of designing a design degree in engineering, using the principles and methodology utilized in engineering design.

It is hoped that this paper will stimulate discussion among engineering professors as this proposal for a B.S. degree in design engineering is open to suggestions and constructive criticism.
Concurrent Engineering: The Disposal Perspective
Authors: Cleetus K. J.
Published: March 2021

This paper follows up the suggestion made in an earlier note that the disposal of products at the end of their useful life, and of by-products of their use, should be considered at the time of product design. Practical suggestions are made on how to incorporate the disposal perspective in a concurrent engineering team. Doing this will reduce the life-cycle cost, and incidentally encourage an approach to design that promotes full recoverability of materials and a safe environment. Taken together these recommendations will be instrumental in avoiding the privation and scarcity that will surely result from neglecting the far downstream perspectives of product development. The ideal of 100% recoverability of materials is held out as possible, provided solar power becomes viable soon. In the final section an initial set of disposability guidelines for designers is presented. They deserve to be deepened. Efforts to standardize recycling processes are essential to reduce the enormous variety existing today.
Collision Detection of 3D Complex Objects
Authors: Mo Rong , Nowacki Horst
Published: March 2021

Collision detection of 3D complex objects is often needed for practical applications. In this paper, a new algorithm for testing collision is proposed. The algorithm combines the sweeping technique and a parametric surface modeling method. A collision detection process is carried out firstly in continuous time using sweeping, in order to determine a time interval for collision as early as possible. In the second step the collision detection is performed at discrete time in this time interval, so that exact collision positions and times are found.