bluuebunny/crossref_metadata_2025 huggingface dataset:
Frequent problems and their management among mechanically ventilated critically ill elderly patients
Authors: Tabootwong Watchara , Kiwanuka Frank
Published: March 2021

Purpose

Multiple pathologies and age-related physiological changes lead to acute respiratory failure. This necessitates mechanical ventilation among elderly patients. Mechanically ventilated critically ill elderly patients may confront various problems, including physical and psychological issues. Therefore, the purpose of this paper is to present the frequent problems encountered by critically ill elderly patients and management of such problems.

Design/methodology/approach

This paper reviews relevant literatures.

Findings

Physical problems include pain and respiratory infections. Additionally, psychological problems include anxiety and stress. Such problems should be managed by physicians, nurses and family members. Pharmacological and non-pharmacological approaches can be used to manage these problems. Pharmacological management involves use of medications, while non-pharmacological interventions include use of music therapy, acupuncture and sensory stimulation.

Originality/value

The paper indicates physical and psychological problems of mechanically ventilated critically ill elderly patients. To ensure effective management of complications encountered by mechanically ventilated elderly patients, health-care professionals ought to be aware of physical and psychological age-related changes.
Tax avoidance and firm risk: evidence from China
Authors: Cao Yuqiang , Feng Zhuoan , Lu Meiting , Shan Yaowen
Published: March 2021

Prior literature documents puzzling evidence revealing that tax avoidance activities do not affect firm‐specific risk. Using an extended US sample, we find that lower cash effective tax rates (ETRs) are associated with higher future return volatility, supporting the traditional view of tax risk–return trade‐off. In sharp contrast to the US evidence, our analysis of Chinese firms suggests that Chinese state‐owned enterprises (SOEs) with lower cash and GAAP ETRs tend to have lower future risk. In addition, we adopt a difference‐in‐differences approach based on the variations generated by two exogenous, anti‐tax avoidance regulations in China but find no evidence suggesting a causal relationship between tax avoidance and firm risk. Overall, our results suggest that the relationship between tax avoidance and risk varies across countries, sample periods and tax aggressiveness measures, and we highlight the importance of addressing the endogenous nature in future research.
Shaping ability of three thermally treated nickel‐titanium systems in S‐shaped canals
Authors: Gomaa Mohamed A. , Osama Mohammad , Badr Amany E.
Published: March 2021

This study aimed to compare the shaping ability of ProTaper Next (PTN), HyFlex EDM (HEDM) and One Curve (OC) systems manufactured via different thermal treatment methods in simulated S‐shaped canals. Sixty S‐shaped canals in clear resin blocks were enlarged to a final apical size of 25 using PTN, HEDM and OC instruments (n = 20 canals/group). Composite images were obtained by superimposing pre‐ and post‐preparation images. The amount of removed resin was measured perpendicularly to the canal surface in 22 points. Prepared canal width and canal transportation at different levels were determined. Canal aberrations were also recorded. Data were statistically analysed using analysis of variance, the Kruskal–Wallis and the chi‐square tests at a 0.05 significance level. OC produced the most conservative enlargement and better maintained particularly the apical curvature of the S‐shaped canals than HEDM and PTN. OC and HEDM better maintained the canal terminus and coronal curvature than PTN.
Characterizing primate home‐ranges in Amazonia: Using ferns and lycophytes as indicators of site quality
Authors: Cárdenas Ramírez Glenda Gabriela , Jones Mirkka M. , Heymann Eckhard W. , Tuomisto Hanna
Published: March 2021

The habitats present in research sites across Amazonia have usually been characterized only very broadly, for example, as inundated or non‐inundated (terra firma) forests. However, within each of these categories there is considerable variation in soil properties and floristic composition. This variation is likely to determine habitat quality for animal populations through its effects on primary productivity and food availability, thereby affecting carrying capacity. Therefore, comparison of edaphic properties across sites could provide new insight into which factors affect animal foraging patterns, population densities, and home‐range sizes. We provide an example from Estación Biológica Quebrada Blanco in Peruvian Amazonia, where behavioral studies on primates (especially tamarins) have been conducted for more than three decades but little is known about the edaphic or floristic characteristics of the forest they occupy. We used indicator plant species to estimate and map soil base cation concentration and its variability at Estación Biológica Quebrada Blanco. We found that soils in the study area are relatively cation‐poor in a western Amazonian context, which probably translates into low primary productivity. Some differences in soils among the home‐ranges of three tamarin groups were also observed, illustrating the usefulness of the method for detailed habitat mapping.

Abstract in Spanish is available with online material.
Participation as a right to the city: Iranian children’s perspectives about their inclusion in urban decision‐making
Authors: Manouchehri Bahar , Burns Edgar A.
Published: March 2021

To assess children's willingness to participate in decision‐making about urban environments, Iranian children were invited to tell their stories about child inclusion in city affairs. The findings demonstrate children's enthusiasm to have a say, their suggestions of how their ideas can be integrated into planning, and their competency for participation. Despite their willingness, participants indicated awareness of patriarchal cultural views of children and childhood which continue to exclude them from planning involvement. Being denied the exercise of their rights to the city generates a marginalised status, alienating children from achieving appropriate engagement.
Female teachers and the rise of primary education in Italy and Spain, 1861–1921: evidence from a new dataset†
Authors: Cappelli Gabriele , Quiroga Valle Gloria
Published: March 2021

This article provides the first harmonized quantitative evidence on the rise of mass education across the provinces (today's NUTS 3) of Italy and Spain in the period c. 1861–1921. Visual analysis of this new dataset suggests that an important factor linked to the expansion of schooling was the feminization of the teaching profession, something that has been largely neglected so far in quantitative historical studies of educational development. This hypothesis is put to the test using panel‐data models. The results show that the feminization of teaching went hand in hand with the rise of schooling rates by prompting more girls to enrol into primary education. By the beginning of the twentieth century, Italy's gross enrolment rate had surpassed that of Spain—partly as the result of increasing feminization within the primary‐school teaching profession.
A double‐blind sham‐controlled phase 1 clinical trial of tDCS of the dorsolateral prefrontal cortex in cocaine inpatients: Craving, sleepiness, and contemplation to change
Authors: Gaudreault Pierre‐Olivier , Sharma Akarsh , Datta Abhishek , Nakamura‐Palacios Ester M. , King Sarah , Malaker Pias , Wagner Ariella , Vasa Devarshi , Parvaz Muhammad A. , Parra Lucas C. , Alia‐Klein Nelly , Goldstein Rita Z.
Published: March 2021

Impaired inhibitory control accompanied by enhanced salience attributed to drug‐related cues, both associated with function of the dorsolateral prefrontal cortex (dlPFC), are hallmarks of drug addiction, contributing to worse symptomatology including craving. dlPFC modulation with transcranial direct current stimulation (tDCS) previously showed craving reduction in inpatients with cocaine use disorder (CUD). Our study aimed at assessing feasibility of a longer tDCS protocol in CUD (15 versus the common five/10 sessions) and replicability of previous results. In a randomized double‐blind sham‐controlled protocol, 17 inpatients with CUD were assigned to either a real‐tDCS (right anodal/left cathodal) or a sham‐tDCS condition for 15 sessions. Following the previous report, primary outcome measures were self‐reported craving, anxiety, depression, and quality of life. Secondary measures included sleepiness, readiness to change drug use, and affect. We also assessed cognitive function including impulsivity. An 88% retention rate demonstrated feasibility. Partially supporting the previous results, there was a trend for self‐reported craving to decrease in the real‐tDCS group more than the sham‐group, an effect that would reach significance with 15 subjects per group. Quality of life and impulsivity improved over time in treatment in both groups. Daytime sleepiness and readiness to change drug use showed significant Group × Time interactions whereby improvements were noted only in the real‐tDCS group. One‐month follow‐up suggested transient effects of tDCS on sleepiness and craving. These preliminary results suggest the need for including more subjects to show a unique effect of real‐tDCS on craving and examine the duration of this effect. After replication in larger sample sizes, increased vigilance and motivation to change drug use in the real‐tDCS group may suggest fortification of dlPFC‐supported executive functions.
Clinical advantages of robot‐assisted partial nephrectomy versus laparoscopic partial nephrectomy in terms of global and split renal functions: A propensity score‐matched comparative analysis
Authors: Kobayashi Satoshi , Mutaguchi Jun , Kashiwagi Eiji , Takeuchi Ario , Shiota Masaki , Inokuchi Junichi , Eto Masatoshi
Published: March 2021

Objectives

To identify predictors of renal function preservation, and to compare the global and split renal function outcomes of robot‐assisted partial nephrectomy and laparoscopic partial nephrectomy.

Methods

Demographic, operative and pathological data, as well as renal function outcomes, of 251 patients who underwent laparoscopic (n = 104) and robot‐assisted (n = 147) partial nephrectomy between 2008 and 2018 were retrospectively analyzed. Propensity score matching (1:1) was carried out to adjust for potential baseline confounders. Functional outcomes were assessed based on the estimated glomerular filtration rate and dynamic renal scintigraphy (using 99mTc‐mercaptoacetyltriglycine), including renal volumetric analysis.

Results

A total of 98 patients were allocated to each partial nephrectomy group. Ischemic (laparoscopic vs robot‐assisted partial nephrectomy: 29 vs 15 min, P < 0.001) and operative times (181 vs 100 min, P < 0.001) were shorter in robot‐assisted partial nephrectomy. The preservation ratio of global renal function at 3 months (88.3% vs 91.4%, P = 0.040) and 12 months (87.8% vs 91.5%, P = 0.010) postoperatively, and the renal function of the operated kidney (80.3% vs 88.2%, P < 0.001) were greater after robot‐assisted partial nephrectomy. In robot‐assisted partial nephrectomy, the volume of resected parenchyma was significantly smaller (27.2 vs 15.5 mL, P < 0.001), resulting in greater postoperative normal parenchymal volumes (120 vs 132 mL, P < 0.001) and a greater parenchymal preservation ratio (81.1% vs 90.1%, P < 0.001). The parenchymal preservation ratio was the strongest predictor of renal function preservation after surgery (P < 0.001, odds ratio 6.02).

Conclusions

Robot‐assisted partial nephrectomy allows better preservation of split renal function than laparoscopic partial nephrectomy by increasing the parenchymal preservation ratio. This translates into better postoperative global renal function.
Enhanced thermal dissipation confers photoprotection in top leaves despite systemic regulation from lower leaves in cotton
Authors: Meng Haofeng , Yi Xiaoping , Jiang Chuangdao , Zhang Wangfeng , Chow Wah Soon , Zhang Yali
Published: March 2021

To better understand the photosynthetic regulation between lower leaves and top leaves, leaf gas exchange and chlorophyll fluorescence were examined in field and climate chamber grown cotton (Gossypium hirsutum L. cv. Xinluzao 45). Two planting density treatments were used in the field: low planting density (LD) and high planting density (HD), and two artificial shade treatments were used in the climate chamber: no shade (NS) and lower leaves shaded (LS). Our results show that the maximum net photosynthetic rate (Pmax), light saturation point (LSP) and light compensation point (LCP) of top leaves were decreased, but the apparent quantum efficiency of net carbon assimilation (AQE) of top leaves was increased in HD and LS, which had a similar trend to the lower leaves. Although top and lower leaves improved the utilization of light, the fractions of light absorbed by the PSII antenna that is utilized in PSII photochemistry Y(II) and photochemical quenching coefficient (qP) of top leaves and lower leaves were decreased in HD and LS. Furthermore, the fraction of absorbed light that is dissipated thermally via ΔpH and xanthophylls regulated processes Y(NPQ) and non‐photochemical quenching (NPQ) of top leaves were increased in HD and LS. In summary, these results suggest that the light energy utilization and photochemical efficiency of the top leaves in cotton are regulated by the light environment of the lower leaves, and the activation of thermal dissipation confers photoprotection of top leaves despite systemic regulation from lower leaves in cotton. Therefore, considering that cotton is cultivated in high density in most cotton areas of the world, the systemic regulation of photosynthetic capacity in top leaves affected by light environment of lower leaves caused by high‐density cultivation needs to be considered comprehensively in practical production. Then, the optimal photosynthetic capacity of the population can be obtained.
Customising flood damage functions to estimate the carbon footprint of flood‐related home repairs
Authors: Matthews Elizabeth , Friedland Carol , Alsadi Ahossin
Published: March 2021

Flood damage functions are important tools used to estimate potential damage to the built environment from various types of flood‐related hazard events (e.g., hurricanes, riverine flooding). Oftentimes these damage estimates are used to determine the feasibility of flood protection or mitigation projects or to plan for future disasters. While existing standardised functions are used to estimate potential economic loss for residential buildings, functions can be customised to assess the environmental impacts of flood damages for specific building designs. This study presents a methodology for customising functions to estimate the carbon footprint of flood‐related building repairs. Unlike regular home repairs, which are based on material life expectancy, flood repairs are dependent on the severity of the flood hazard (i.e., flood depth) and probability of hazard occurrence within the lifespan of a building. To demonstrate the methodology, customised functions are developed for a case study home design in Saint Petersburg, Florida.
Screening of in vitro nutrient digestibility coefficients of selected insect meals in broiler chickens, black‐meat chickens and quails
Authors: Kovitvadhi Attawit , Chundang Pipatpong , Pliantiangtam Nichaphon , Thongprajukaew Karun , Tirawattanawanich Chanin , Suwanasopee Thanathip , Koonawootrittriron Skorn
Published: March 2021

The objective of this study is to identify potential insect species comparing with commonly used protein sources based on efficiency of the in vitro digestibility on dry matter (DMd), organic matter (OMd) and crude protein (CPd) in broiler chickens, black‐meat chickens (Native breed) and quails. Each of gastric mucosa, pancreas and duodenal mucosa were obtained from proventriculus, pancreas and duodenum, respectively. Crude digestive enzyme extracts (CTE) were extracted from these organs to perform in vitro digestibility. Eighteen insect samples and six commonly used protein sources were served as substrates which were evaluated on DMd, OMd and CPd in triplicate for each substrate. The CTE from gastric mucosa was used to simulate proventriculus, whereas small intestine was simulation by adding the CTE from pancreas and duodenum. The large variation of chemical composition between insect meals was presented. For commonly used protein sources, animal proteins were higher on digestibility than plant proteins (p < .001). Quails represented a great potential to digest insect meals comparing other animals. Based on CPd results, there were potential insect species for broiler chickens (Achroia grisella: AG, Tenebrio molitor: TM and Musca domestica), black‐meat chickens (Patanga succincta, TM and AG) and quails (Hermetia illucens, Acheta domesticus and Locusta migratoria; p < .001). The evidences from this study suggest that these insect species contain a great potential to use as alternative protein sources promoting an animal production with sustainability. However, the in vivo experimentation must be performed to confirm in further study.
Acute changes to breast milk composition following consumption of high‐fat and high‐sugar meals
Authors: Ward Ellen , Yang Ni , Muhlhausler Beverly S. , Leghi Gabriela E. , Netting Merryn J. , Elmes Matthew J. , Langley‐Evans Simon C.
Published: March 2021

Breast milk composition is influenced by habitual diet, yet little is known about the short‐term effects of changes in maternal diet on breast milk macronutrient concentrations. Our aim was to determine the acute effect of increased consumption of sugar/fat on breast milk protein, lactose and lipids. Exclusively breastfeeding women (n = 9) were provided with a control, higher fat (+28 g fat) and higher sugar (+66 g sugar) diet over three separate days at least 1 week apart. Hourly breast milk samples were collected concurrently for the analysis of triglycerides, cholesterol, protein, and lactose concentrations. Breast milk triglycerides increased significantly following both the higher fat and sugar diet with a greater response to the higher sugar compared to control diet (mean differences of 3.05 g/dL ± 0.39 and 13.8 g/dL ± 0.39 in higher fat and sugar diets, respectively [P < 0.001]). Breast milk cholesterol concentrations increased most in response to the higher sugar diet (0.07 g/dL ± 0.005) compared to the control (0.04 g/dL) and the higher fat diet (0.05 g/dL) P < 0.005. Breast milk triglyceride and lactose concentrations increased (P < 0.001, P = 0.006), whereas protein decreased (p = 0.05) in response to the higher fat diet compared to the control. Independent of diet, there were significant variations in breast milk composition over the day; triglycerides and cholesterol concentrations were higher at end of day (P < 0.001), whereas protein and lactose concentrations peaked at Hour 10 (of 12) (P < 0.001). In conclusion, controlled short‐term feeding to increase daily sugar/fat consumption altered breast milk triglycerides, cholesterol, protein and lactose. The variations observed in breast milk protein and lactose across the 12 h period is suggestive of a circadian rhythm.
Symptomatic spinal cord compression: an uncommon symptom in pseudohypoparathyroidism
Authors: Tan Xiaoping , Guo Yang , Liu Yan , Liu Cong , Pei Lina
Published: March 2021

We describe symptomatic spinal cord compression associated with pseudohypoparathyroidism (PHP) in a young female patient and reviewed similar cases previously reported in the literature. The characteristics of these cases were analyzed from etiology, clinical subtypes, symptoms, treatment, and prognosis. Neurological examination revealed functional upper extremities with bilateral lower extremity paraplegia. Laboratory tests showed hypocalcemia, hyperphosphatemia, and elevated parathyroid hormone; high‐throughput sequencing showed a heterozygous GNAS mutation in exon 12, specifically c.1006C > T (p.R336W). Imaging findings showed multilevel spinal stenosis with significant spinal cord compression at the T2–T3 level. Seventeen cases with similar characteristics were reviewed. We found that the primary clinical manifestation of these patients was bilateral lower extremity spastic paraplegia. Multilevel spinal cord compression was commonly observed, especially at the lower cervical and upper thoracic spinal cord. Most of the patients had poor surgical treatment outcome and prognosis. Clinicians should be aware of paraplegia due to spinal cord compression as a rare neurological complication in patients with PHP. Early diagnosis and treatment of PHP is one basis for preventing severe spinal cord–related complications.
Evaluation of HPV and EBV in OSCC and the expression of p53, p16, E‐cadherin, COX‐2, MYC, and MLH1
Authors: de Lima Marcos Antonio Pereira , Cavalcante Roberta Barroso , da Silva Cláudio Gleidiston Lima , Nogueira Renato Luiz Maia , Macedo Geamberg Einstein Cruz , de Galiza Lara Eduardo , Pinheiro Juliana Viana , Maia Filho Pedro Hugo Bezerra , Santos Sarah Ferreira , Rabenhorst Silvia Helena Barem
Published: March 2021

Objective

This study aimed to evaluate the presence of human papillomavirus (HPV) and Epstein–Barr virus (EBV) and the expression of p53, p16, E‐cadherin, COX‐2, MLH1, and MYC in oral squamous cell carcinoma (OSCC).

Materials and Methods

One hundred OSCC specimens were submitted to in situ hybridization for HPV and EBV, and immunohistochemistry for detection of the human proteins.

Results

Thirty‐one cases showed HPV in tumor tissue. EBV was not detected in any case investigated. The HPV(+) group demonstrated an increase of staining scores for nuclear p16 (p = .047), cytoplasmic MYC (p = .002), while a decrease for nuclear MLH1 (p = .048), suggesting that HPV may upregulate the expression of the first two proteins and down‐regulate the latter.

Conclusion

Our findings reinforce the hypothesis of the HPV‐related oral carcinogenesis involving the expression of p16 and MYC, and MLH1 suppression. Exclusively cytoplasmic stainings for p16, MLH1, and MYC were also associated with more advanced tumors. Finally, in view of the lack of studies correlating the HPV or EBV infection to the expression of oncoproteins, more researches assessing a broader panel of markers and employing different approaches are still necessary in order to understand the role of these viruses as well as the molecular mechanisms involved in the development and progression of oral carcinomas.
Evolution of salmon lice in response to management strategies: a review
Authors: Coates Andrew , Phillips Ben L. , Bui Samantha , Oppedal Frode , Robinson Nick A. , Dempster Tim
Published: March 2021

Ectoparasitic salmon lice (Lepeophtheirus salmonis) present a major challenge to Atlantic salmon (Salmo salar) aquaculture. The demand for effective louse control has produced diverse management strategies. These strategies essentially impose novel selection pressures on parasite populations, driving the evolution of resistance. Here we assess the potential for salmon lice to adapt to current prevention and control methods. Lice have evolved resistance to at least four of five chemical therapeutants, and use of these chemicals has declined significantly in recent years. The industry has shifted to alternative non‐chemical approaches, yet lice may adapt to these as well. Early research suggests that phenotypic variation exists in the louse population upon which non‐chemical selection pressures could act and that this variation may have a genetic basis. From the existing evidence, as well as an examination of evolutionary processes in other relevant parasite and pest systems, we conclude that the evolution of non‐chemical resistance is an emergent concern that must be considered by the industry. We recommend areas for focused research to better assess this risk. It is also important to determine whether phenotypic shifts in response to non‐chemical selection may shift the ecological niche of the parasite, as this may have cascading effects on wild salmon populations. We also recommend further research to identify strategy combinations that have antagonistic selective effects that slow louse evolution and those with synergistic effects that should be avoided. Greater understanding of evolutionary processes can inform aquaculture policies that counteract the rise of resistant parasite populations.
Eliminating buyer’s remorse: An examination of the sunk cost fallacy in the National Hockey League draft
Authors: Farah Lou , Baker Joseph
Published: March 2021

The sunk cost effect describes the tendency to escalate one's commitment toward a certain endeavor, despite diminishing returns, as a consequence of irreversible resource expenditure that has already been made (Organ Behav Hum Decis Process. 1985;35:124). This effect has been observed in a number of professional sports leagues, wherein teams escalate their commitment toward players selected early in the draft, regardless of performance outcomes, due to large financial commitments invested in them (J Sports Econom. 2017;18:282; Adm Sci Q. 1995;40:474). This effect, however, has yet to be explored in the National Hockey League (NHL). The purpose of this study was to test for sunk cost effects in the NHL, by examining the relationship between draft order and playing time, while controlling for a myriad of confounding variables. Findings from our analyses provide support for the existence of this effect in the NHL, as first‐round draftees were given significantly more playing time than their peers selected in the second round, regardless of injury, player relocation, penalties, or on‐ice performance outcomes. We offer some plausible underlying mechanisms driving this effect. Furthermore, we suggest the observed effects have valuable implications for NHL talent development, given the importance of playing time on various aspects of expertise attainment.
EMAT: An Engineering Methodology Application Tool
Authors: Wang Nanxin , Cheng Jie
Published: March 2021

More and more applications in today’s automotive industry call for integration of existing product design/analysis programs into packages to perform a higher level of system functionality, such as total engine analysis, model-based engine mapping, and powertrain system or vehicle optimization. The functional and procedural specifications for these integrations are often referred to as engineering methodologies. To enable the rapid prototyping of these methodologies, a generic software integration framework, EMAT (Engineering Methodology Application Tool) has been developed. EMAT consists of a high-level language environment MDL (Methodology Description Language) and a program for process execution scheduling and monitoring based on an artificial intelligence technology called Blackboard. Under the EMAT framework, a user can easily specify the control flow and data flow for any methodology in a declarative manner. Such a specification only needs to contain logical orders in which individual component programs will be executed (such as sequence, branching, or looping), and the input/output connections between the programs. EMAT will then dynamically interpret this specification into procedures that actually carry out the execution. In contrast to the conventional integration practices such as developing application specific scripts, EMAT provides a generic and high level means for integration, which improves hot only the efficiency of programing, but also the modularity, maintainability, and reusability of software. EMAT is currently being applied to the integration of multiple engine simulation programs to prototype complicated engineering methodologies for a wide range of applications within FORD.
A Concurrent Engineering System for Legal Reasoning About Defective Design
Authors: Sethi Achint , Fischer David A. , Butler Alley C.
Published: March 2021

Concurrent engineering is focused on improving the Product Realization Process by more effectively integrating manufacturing issues into engineering design. Expansion of the Concurrent Engineering paradigm to include a broader range of concerns is advocated, and this paper examines the integration of legal issues into the Product Realization Process. It describes a prototype legal expert system that focuses on product design based on defective design product liability law. The legal reasoning process is modeled using a fuzzy logic architecture. The goal for this prototype system is the development of a workstation based advisor to engineers that automates assessment of potential legal liability for defective design. As a Concurrent Engineering tool, this fuzzy system allows engineers to make modifications during preliminary design, thereby avoiding the more painful process of modifying designs after litigation. Results with this system are discussed, and it is concluded that the fuzzy logic architecture appears to offer a suitable approach.
Applications of Non-Manifold Topology
Authors: Charlesworth William W. , Anderson David C.
Published: March 2021

It is widely recognized that a solid model based on a non-manifold boundary representation can have a more complicated surface topology than one based on a manifold boundary representation, but non-manifold topology has other capabilities that may be more valuable to the application developer. Non-manifold topology can be put to use in existing application areas in ways that differ significantly from the techniques developed for manifold modeling and it can be put to use in new applications that have not been satisfactorily solved by manifold topology. Several applications of non-manifold topology that would be difficult or impossible to implement using a purely manifold geometric modeler are illustrated: automatic formulation of finite element analyses from solid models, automatic generation of machining tool paths for 2½-dimensional pockets, and construction of geometric models using topological constraints. These applications demonstrate how a non-manifold model partitions the entire space in which an object is embedded, preserves elements of the model that would be discarded by conventional schemes, and permits the implementation of a common merge operation. All three applications have been implemented using a two dimensional non-manifold (non-1-manifold) geometric modeler.
Superior Mesh Quality With Automatic Node Mergers
Authors: Gutfinger Ron S.
Published: March 2021

Automatic surface meshers have been designed with the intent to eliminate the manual effort involved in creating a finite element model. Naturally, the quality of the mesh must be such that the solver will yield accurate results. For geometries having boundaries with short edges relative to the rest of the geometry, the existing meshers yield poor quality meshes. Hence, the stress analyst must manually attain reasonable mesh quality. This manual effort is very tedious and time consuming. Mesh quality improvement techniques such as smoothing, fail to improve the mesh quality. In this work, a new technique is introduced, which improves the initial boundary node loop quality, and in turn yields high quality meshes. Examples show marked improvement in quality, and the meshes are comprised of fewer elements.
Stress Analysis of the Target Enclosure at the R14B Firing Range
Authors: Gupta Aaron D.
Published: March 2021

A stress analysis of the target enclosure structure at the R14B firing range at Aberdeen Proving Ground (APG), MD, subjected to an internal blast and worst-case fragment impact was conducted to assure structural integrity and safe operation of the structure during tests. The reflected dynamic pressure loads due to explosive blast were estimated from the CONWEP explosion effects code developed by the U.S. Army Waterways Experiment Station and were modeled as exponentially decaying pressure pulses which could be approximated as triangular loads with equivalent impulses. Fragment impact loads are approximated from a momentum-impulse balance formulation as step loading functions. A closed-form solution of the equation of motion of a sidewall of the structure subjected to a triangular blast load was obtained and verified by a three-dimensional (3-D) finite element model.
A Boundary Element Method for Multi-Body Contact Problems and its Application to the Analysis of a Huge Excavator
Authors: Liu Chong-De , Yu Jiyuan , Wang Xiaoming
Published: March 2021

The derivation of a boundary integral formulation and discretization technique in terms of boundary elements for the solution of multi-body contact problems has been carried out. A FORTRAN program has been developed based on this boundary element formulation and has been applied to the stress analysis of a huge caterpillar excavator woth 16 m3 bucket capacity.
REFINED: A Computer Code for

R

eacting

E

lliptic

F

lows

in

E

xpansion

D

omains
Authors: Dong M. , Lilley D. G.
Published: March 2021

REFINED (acronym for Reacting Elliptic Flows inExpansion Domains) is a general computer code that has been developed for turbulent swirling reacting flow predictions. A variety of user choices, such as inlet velocity profiles, inlet flow parameters, chemical reaction schemes from user-oriented accuracy and complexity requirements, and interaction with flowfield color graphic display utility are included. Development of the computer code is documented, with emphasis on the theory and application of the methodology.
Development of Interactive Tutorials to Aid in Teaching of a Rapid Design Prototyping Laboratory Course
Authors: Biswas Arunava , Kinzel Gary L.
Published: March 2021

A rapid design prototyping facility comprising of table top CNC milling machines, CNC lathes, CAD/CAM workstations and an injection molding machine has been established at the Ohio State University. Interactive tutorials have been developed for helping the users to learn the details of the machines and the software programs. The tutorials have successfully improved the learning efficiencies of the students and reduced the training costs for instructors. This paper presents an overview of the tutorials.
Computer Graphics Modeling of Anatomy: From 2D Data Acquisition to 3D Sculpting
Authors: Alciatore David G.
Published: March 2021

This paper describes a process which is used to generate three-dimensional computer graphics surface models of gross anatomical structures. Key steps in the generation of these models include acquiring 2D cross-sectional data from macrocryotome slicing, generating 2D cross section contours from edge detection and region segmentation, generating a polygonal mesh surface model by triangulating between the 2D contours, and interactive sculpting of the 3D surface for editing and changing the appearance of the model. The algorithms and development involved with these steps are briefly described here and several images resulting from the process are presented. The main purpose of the paper is not to present the details of implementation of the various algorithms, but rather to present the overall methodology and illustrate the results. Implementation details can be found in other papers referenced here. The most recent results of our efforts, which are presented here, are 3D surface models of the complete human thorax. These models have numerous applications in anatomy and biomechanics visualization and teaching.
On Developing User’s M Files for MATLAB in Engineering Applications
Authors: Pao Y. C.
Published: March 2021

This paper presents a collection of M files created for applications of MATLAB software in graduate and undergraduate engineering classes. Starting with the simple need of printing a difference table, presented in order of increasing difficulty of numerical procedural setup and programming arrangement are M files for volume integration, animation of a rotating block, Runge-Kutta solution of a nonlinear oscillation problem, and solution of a warping function governed by Laplace equation using the relaxation method. Threading through these M files are the demonstrative applications of MATLAB’s own M files and its graphics commands and vector operations.
Integration of CAD to CAM Through Feature Recognition Based Solid Modeling
Authors: Jha Prabhudutt
Published: March 2021

This paper deals with the development of a system to convert a general positive-based solid geometry data set into one more suitable for process planning. The basic software used is IDEAS for solid modeling on IBM/RS 6000 workstation.

The objective is to capture design and manufacturing knowledge in existing engineering drawings of CAD/CAM databases and then convert the captured design features into workable products through feature recognition techniques.

The paper presents an approach of converting CSG geometry representation to a DSG (Destructive Solid Geometry) form and then results are written to I-DEAS program file. The user can examine the excess materials for removal from model file, where it is stored. The program is written in FORTRAN 77.
Unified Feature Definition for Feature Based Design and Feature Based Manufacturing
Authors: Geelink Reinholt , Salomons Otto W. , van Slooten Fjodor , van Houten Fred J. A. M. , Kals Huub J. J.
Published: March 2021

In this paper, interactive “constraint based feature definition” is used to drive both feature based design and feature recognition. At present, hardly any feature based CAD or CAPP system does offer adequate facilities to easily define application specific features. Feature definition by means of programming is an error prone and difficult task. The definition of new features has to be performed by domain experts in the fields of design and manufacturing. In general they will not be programming experts. This paper elaborates on interactive feature definition, aiming at facilitating the definition of features by non-programming experts. The interactive feature definition functionality is implemented in a re-design support system called FROOM. It supports feature based design. Feature definition is also used in a Computer Aided Process Planning system, called PART, for the definition of features to be recognized. Conceptual graphs are used as an aid in the definition of features and for the representation of the features. The conceptual graphs are automatically transformed into feature recognition algorithms. Degrees of freedom (DOF) analysis is used for support during feature definition and for solving geometric constraints related to the feature to be defined.
Features: Semantic Objects for the Integration of Tasks in the Product Development Process
Authors: Krause F.-L. , Ciesla M. , Rieger E. , Stephan M. , Ulbrich A.
Published: March 2021

For the integration of the tasks to be mastered within the development process it is necessary to take account of non-geometrical information, from product design to manufacturing process, alongside geometrical design shape. The introduction of objects as carriers of semantic information leads to the use of features. In the present contribution, a concept and its realization are described that facilitate a flexible definition and computer-internal representation as well as the interpretation of features as semantically endowed objects. Based on the feature model, approaches are introduced for the support of product development with the partial tasks conception, design, integrated planning of manufacture and quality assurance.
An Efficient System for Geometric Assembly Sequence Generation and Evaluation
Authors: Romney Bruce , Godard Cyprien , Goldwasser Michael , Ramkumar G.
Published: March 2021

In this paper, we present a software system which can automatically determine how to assemble a product from its parts, given only a geometric description of the assembly. Incorporated into a larger CAD tool, this system, the Stanford Assembly Analysis Tool (STAAT), could thus provide immediate feedback to a team of product designers about the complexity of assembling the product being designed. This would be particularly useful in complex assemblies where each designer may not be fully aware of the impact of his design changes on the assemblability of the product as a whole. STAAT’s underlying data structure is an efficient version of the non-directional blocking graph (NDBG), a compact representation of the blocking relationships in an assembly. STAAT implements several techniques using this structure, under a unified approach in which the same software “machinery” can analyze the product under different assembly constraints. In initial experiments conducted on relatively small polyhedral assemblies of 20 to 40 parts and 500 to 1500 faces, using one-step translational motions, STAAT generated assembly sequences much more quickly than did previous NDBG-based systems. We are working now on extending both these results and the underlying theory to more sophisticated cases.
Geometric Reasoning for the Coding of CAD Models
Authors: Qamhiyah A. Z. , Benhabib B. , Venter R. D.
Published: March 2021

Many of today’s concurrent product-development cycles depend on the utilization of intelligent Computer-Aided Design (CAD) systems. Thus, it would be essential to provide CAD users with effective means for interacting with the CAD system and its database. This paper addresses the development of a boundary-based coding procedure for CAD models. Coding the geometric and processing characteristics of objects, based on their CAD model representation, has been long recognized as an effective approach that allows convenient design retrieval on the one hand and process-planning automation on the other. Our work is based on the assumption that form features are recognizable and extractable from the CAD model by current feature-recognition, feature extraction and feature-based-design approaches. The coding procedure is applicable to the boundary representation of the object and its extracted form features.
Extension of Feature-Based CAD Systems Using TAE Structures to Support Integrated Rapid Prototyping
Authors: Otto Harald E. , Kimura Fumihiko , Mandorli Ferruccio , Cugini Umberto
Published: March 2021

Due to life cycles of artifacts, which become shorter, rapid prototyping development and tight feedback among product requirements, design, and manufacturing are gaining increasing importance. Classical rapid prototyping technologies such as computer-numerically-controlled (CNC) machinery, which remain still time consuming and expensive, are getting superseded by a growing propensity to apply new solid freeform fabrication (SFF) technologies, which became commercially available since 1987.

Although, being on the market for only less than a decade, remarkable progress in various directions such as accuracy, used materials, through-put, and equipment costs, has been achieved in SFF technologies.

However, there are still several technological as well as methodological problems left. Within given scope, we would like to tackle some, taken from the methodological field, which seems still weakly developed compared to existing technology. Within our approach we apply feature-based models and techniques, realized within typed attributed entity (TAE) structures. In particular, we are interested in the handling of additional fabrication relevant form structures and the automatic determination of fabrication parameters.

To verify developed methodologies and to demonstrate the applicability of our taken approach, several selected parts, taken from precision machinery engineering and aerospace engineering were modeled and processed. An implemented prototype environment and a stereolithography apparatus (SLA) were used for integrated knowledge handling, computation and SFF fabrication.
Part Selection From a Federated Catalog
Authors: Jiang Ling , Brown Don R. , Hwang Kuo-Yen
Published: March 2021

This paper discusses issues related to a network-based catalog part selection system. Some of the key issues are: the optimal search problem, the burden imposed on the server of a network-based catalog or the time spent in data retrieval, identical parts in different vendor catalogs, and the excessive amount of data in a database of component information. The paper addresses the problem of network “burden,” the problem of identical parts, and the excessive data problem. The authors employ a “Configuration-decomposition” strategy in the approach to the excessive data problem. As an example of applying this approach, the implementation of the authors’ experimental system for part selection is discussed.
Geometric Improvement on Ribbed Globoidal Cams for Unsymmetrical Motion Controls
Authors: Tsay Der Min , Lin Bor Jeng
Published: March 2021

A procedure with design and machining considerations is developed to define unsymmetrical turret motions of ribbed globoidal cams. Adjusting the parameters of rational B-splines to interpolate required angular motion constraints, one can refine the turret motion that is superior to those obtained by other traditional methods. To judge the geometric performance of the spatial cam surface corresponding to its turret motion, the envelope theory is applied to derive the analytical description of the cam surface. As a result, the pressure angle and the curvature of the cam surface can be investigated. A real example is illustrated to show the effectiveness of the procedure and the favorable results compared to those obtained by other means.
Computer Prototyping of Moving Mechanical Parts
Authors: Pai Uday N. , Liou F. W.
Published: March 2021

In this paper computer implementation of automated simulation of rigid bodies in collision is presented. It can be used for automatic simulation of unconstrained and/or constrained mechanical systems. The key tasks include feature extraction, collision detection, constraint identification, collision response, and simulation. Feature extraction includes volumetric feature extraction such as mass, volume, density and moment of inertia, and planar geometric feature extraction like the faces, edges, vertices and their inter-relationships. Collision detection is a kinematic problem involving the positional relationships of rigid bodies in space, while collision response is a dynamic problem involving the prediction of rigid body behavior according to physical laws. Case studies are used to explain the behavior of a typical system comprising of two rigid bodies to explain the underlying principles.
A Method for Embedding Human Expert Knowledge Into a Fuzzy Logic Controller
Authors: Canning John R. , Edwards Dean B.
Published: March 2021

This paper presents a method for embedding human expert knowledge into a fuzzy logic controller. The method was developed while designing a fuzzy logic control system for an autonomous vehicle that utilized sparse sensor data for terrain classification. We will discuss the design for the fuzzy logic terrain classification system and use it as an example for explaining the embedding method.

In the example, a human expert classified terrain features from sensor data provided by a two-dimensional computer simulation. From the information derived from the expert, we developed both a classification system for the terrain features and a fuzzy logic rule base for the controller. The simulation, along with an optimization algorithm, was then used to train the fuzzy logic controller to match the human responses.