bluuebunny/crossref_metadata_2025 huggingface dataset:
Shifts in composition of fish species of fishery in Lake Naivasha, Kenya: Trend implications for fishing effort, yields and revenue
Authors: Morara George N. , Getabu Albert M. , Njiru James M. , Omondi Reuben , Mutie Alice , Nyamweya Chrisphine S.
Published: March 2022

Assessing fisheries resource composition and exploitation trends is vital for the sustainable management of fish stocks. Accordingly, the present study analysed datasets of fish catches and market values from 1991 to 2019, and from 2004 to 2019, respectively, to determine shifts and trends in fish species composition, fishing effort, fish yield and revenue. The annual percentage weight composition and relative biomass of different fish species in the lake were calculated over the study period. Fishery time series data comprised fishing effort, fish yield, catch per unit effort (CPUE), revenue and revenue per unit effort (RPUE). Moving average (MA) trends at 5‐year intervals were plotted and the Mann–Kendall (MK) method applied to detect trends at the 95% confidence limit. The results identified shifts in fish species composition during various periods, with Nile tilapia Oreochromis niloticus comprising 94% of the total weight of fish landed in 2019, with an overall mean relative biomass of 4221.4 ± 2229.7 kg/km2. The mean total fish catch (1683.5 ± 420 ton/year), CPUE (10.6 ± 2.0 ton/boat/year) and modal effort (176 boats) were highest from 2014 to 2019 period. The fishery revenue increased in 2019 (US$ 4,096,490) with a RPUE of US$ 22,263.5/boat/year. The fishing effort, fish yields, CPUE, revenue and RPUE trends increased significantly (p < .01), likely being related to the shifts in species composition. Lake Naivasha is a learning model for improving fisheries management and yields through stock enhancement interventions. Nevertheless, the increasing level of fishing effort warrants a precautionary approach to ensure sustainability of the fishery resource.
You Are What Your Mother Endured: Intergenerational Epigenetics, Early Caregiving, and the Temporal Embedding of Adversity
Authors: Lappé Martine , Jeffries Hein Robbin
Published: March 2022

Environmental epigenetics has become a site of growing attention related to the intergenerational effects of stress, trauma, and adversity. This article draws on a multi‐sited ethnography of epigenetic knowledge production in the United States and Canada to document how scientists conceptualize, model, and measure these experiences and their effects on children's neurodevelopmental and behavioral health. We find that scientists’ efforts to identify the molecular effects of stress, trauma, and adversity results in a temporal focus on the mother–child dyad during early life. This has the effect of biologizing early childhood adversity, positioning it as a consequence of caregiving, and producing epigenetic findings that often align with individually oriented interventions rather than social and structural change. Our analysis suggests that epigenetic models of stress, trauma, and adversity therefore situate histories of oppression, inequality, and subjugation in discrete and gendered family relations, resulting in the temporal embedding of adversity during early life.
Maternal offloading of arsenic and other trace elements in Peruvian fur seals
Authors: Kooyomjian Catherine , Giarikos Dimitrios G. , Adkesson Michael J. , Hirons Amy C.
Published: March 2022

The maternal transfer of 15 elements was examined in Peruvian fur seal (Arctocephalus australis) dam and pup paired vibrissae (whiskers), serum, and milk samples collected from 2009 to 2019. Pup vibrissae, grown in utero, represented gestational transfer, while milk represented lactational transfer. Element concentrations, except arsenic, were highest in vibrissae compared to serum and milk for both dams and pups. Mean arsenic concentrations in pup vibrissae (0.44 μg/g) and milk (0.41 μg/g) were twice as high as dam vibrissae concentrations (0.19 μg/g) and nearly ten times higher than dam (0.06 μg/g) and pup serum (0.04 μg/g) concentrations. Mean arsenic concentrations from 2011 to 2019 increased in dam vibrissae (0.026 μg/g to 0.262 μg/g) and milk (0.361 μg/g to 0.484 μg/g). Pup vibrissae had significantly higher concentrations for 11 of the 15 elements analyzed compared to dam vibrissae, suggesting that element transfer is occurring through recent exposure and remobilization of elements from dam body stores. Potentially high concentrations of aluminum, arsenic, copper, and lead in pup tissues may impact their survival and population health. The impact of regional mining activities can contribute to elevated trace elements through runoff and pose a possible threat to local marine environments.
Emergent L2 Grammars in and for Social Interaction: Introduction to the Special Issue
Authors: PEKAREK DOEHLER SIMONA , ESKILDSEN SØREN W.
Published: March 2022

Setting the stage for the central themes and the articles in this special issue, this introduction delineates the epistemological confluences, complementarities, and differences among conversation analysis (CA), on the one hand, and 2 strands of usage‐based linguistics, on the other—namely, usage‐based second‐language acquisition (SLA) and interactional linguistics. This implies depicting how an increased interest in actual usage within the field of linguistics, including usage‐based SLA, has converged with the basic assumptions in CA and interactional linguistics: (a) Language use is primordially and primarily situated in social interaction, and (b) language emerges out of social interaction. We scrutinize the grounds for combining the 3 frameworks for investigating second language development, illustrate such combination through the discussion of some of the rare existing studies that integrate these frameworks, and argue for the need to develop the methodological combinations further in order to move toward an ecologically more valid understanding of how language develops out of language use. On that basis, and additionally drawing on the individual contributions to the special issue, we then outline some implications for L2 education.
A taxonomic revision of Psephellus sect. Psephelloidei (Asteraceae, Cardueae–Centaureinae) from Iran
Authors: Rezaei Elham , Negaresh Kazem , Saeidi Hojjatollah
Published: March 2022

A taxonomic revision of Psephellus Cass. sect. Psephelloidei (Boiss.) Wagenitz (Asteraceae) in Iran is preented. Four taxa are recognized and one of them from East Azerbaijan Province, NW Iran, is described as a new species: Psephellus sennikovianus Negaresh. Psephellus gilanicus (Bornm.) Wagenitz and P. leuzeoides (Jaub. & Spach) Wagenitz are lectotypified. Images of the type specimens of all species and photos of the species in their natural habitats are provided. In addition, the geographic distribution of all the four species recognized is presented and mapped. Finally, a taxonomic key to species of the section Psephelloidei in Iran is provided.
The symptom burden of Irritable Bowel Syndrome in tertiary care during the COVID‐19 pandemic
Authors: Noble Hithin , Hasan Syed Shariq , Whorwell Peter J. , Vasant Dipesh H.
Published: March 2022

Background

The COVID‐19 pandemic caused unprecedented disruption to healthcare services worldwide with well‐documented detrimental effects on mental health. Patients with refractory disorders of gut‐brain interaction such as Irritable Bowel Syndrome (IBS) seen in tertiary care tend to exhibit higher levels of psychological comorbidity, but the impact of the pandemic on IBS symptom severity in tertiary care is unknown.

Methods

As part of routine clinical care, consecutive tertiary referrals with refractory IBS patients prospectively completed a series of baseline questionnaires including IBS symptom severity score (IBS‐SSS), non‐colonic symptom score, Hospital Anxiety and Depression (HAD), and Illness impact scores. The symptom severity questionnaire data were compared for consecutive patients seen in tertiary care 12 months before and after the onset of COVID‐19 pandemic restrictions.

Key Results

Of 190 consecutive tertiary referrals with IBS, those seen during the pandemic had greater IBS severity (IBS‐SSS: 352 vs. 318,p = 0.03), more severe extra‐intestinal symptoms (non‐colonic score: 269 vs. 225,p = 0.03), sleep difficulties (p = 0.03), helplessness and loss of control (p = 0.02), but similar HAD‐Anxiety (p = 0.96) and HAD‐Depression (p = 0.84) scores. During the pandemic, unmarried patients (p = 0.03), and keyworkers (p = 0.0038) had greater IBS severity.

Conclusions and Inferences

This study has shown for the first time that patients seen in tertiary care with refractory IBS during the COVID‐19 pandemic had a significantly higher symptom burden emphasizing the importance of gut‐brain axis in IBS. Furthermore, lack of support and perceived loss of control appear to be contributory factors.
Does Competition Increase or Decrease Price Dispersion? Insights from One‐Way vs. Round‐Trip Airfares*
Authors: Kim Myongjin , Shen Leilei , Ge Qi
Published: March 2022

Does competition increase or decrease price dispersion? Our study addresses this long‐standing debate by presenting an intriguing empirical puzzle. Specifically, leveraging an extended panel from the U.S. airline industry between 1993 and 2013, we find that competition intensity and price dispersion are positively correlated for one‐way tickets but negatively correlated for round‐trip products. We posit that the recent growth in one‐way ticket sales may have led airlines to adjust their pricing strategies to allow for more effective market segmentation. Our study contributes to the empirical literature on price dispersion across multiple goods and helps inform antitrust policy on product bundling.
Lateral Malleolus Reconstruction After Tumor Resection in Children: A Case Report and Literature Review
Authors: Long Zuo‐Yao , Lu Yajie , Chen Guojing , Li Minghui , Huang Mengquan , Xiao Xin , Wang Zhen , Li Jing
Published: March 2022

Background

Pediatric reconstruction of lateral malleolus was necessary and challengeable. Up to now, vascularized fibular was the optimal graft to reconstruct epiphyseal defection. However, the sophisticated microvascular operation has limited the wide application of this technique.

Case Presentation

We present the case of a 9‐year‐old boy with Ewing sarcoma in left distal fibula. In order to restore the growth capacity, we used reverse‐flow vascularized fibular epiphyseal graft with tibialis anterior artery to reconstruct the bone defect after tumor resection with no microvascular anastomosis. More than 4 years after the operation and adjuvant chemotherapy, the patient was free of pain and recurrence, and the function and stability of ankle joint was perfect. Radiology examination revealed satisfied bony union of fibula and normal growth of the fibular head transplant.

Conclusions

The advantage of reverse‐flow vascularized fibular epiphyseal graft is requiring no microvascular anastomosis which could not only shorten operating time, but also reduce factitious damage of vessels. This report presented that this technique might be an available option for reconstruction of lateral malleolus in children.
Public health awareness of climate change's impact on health
Authors: Zust Barbara , Jost Rose
Published: March 2022

Objective

Climate change impacts the public's health. People are at risk for extreme weather events in the 21st century. The purpose of this study was to assess Public Health agencies’ awareness of climate change's impact on health, and what protective and preventive strategies the agencies have in place.

Method

Using mixed method research, a survey was designed to collect quantitative and qualitative data. Following IRB approval, surveys were sent to eight Public Health agencies in the USA's rural and urban Midwest, and rural Alaska.

Analysis

Quantitative data were analyzed using simple frequencies and means. Qualitative data were analyzed using content analysis and Public Health frameworks.

Results

Thirty‐three agency personnel completed the surveys. All agencies identified emerging, new health problems. Seven agencies had climate change doubters and/or opposition from the community regarding climate change reality. All eight agencies were underfunded.

Conclusion

Public Health agencies need financial resources to prepare for climate change threats and events. Climate change is a global reality. The world needs to collectively work together on this issue.
Innovation and partnerships: Meeting the health care needs of a houseless population
Authors: Fox Kelly , Benes Lindsay L. , Harrington Emily
Published: March 2022

Achieving health equity in the houseless population will take innovation, collaboration, and forward‐thinking alternative models of health care. Using a foundation of disruptive innovation and an evidence‐based care model, a group of nurses drew upon established partnerships to create Oregon's first nurse‐owned and fully nurse‐operated clinic serving the houseless population. The Harrington Health Clinic offers primary care, mental and behavioral health care, health and wellness, palliative care, and telemedicine services to men in a transitional housing program. Since its launch in January 2021, the clinic has served over 100 men spanning nearly 400 visits. The clinic attributes much of its success to registered nurses and nurse practitioners operating at the top of their scope, an academic affiliation that promotes learning‐centered practices, and partnership with organizations similarly committed to just and equitable care. Through high quality, equitable primary care, this nurse managed and owned clinic has created a replicable solution that can impact houseless populations across the country.
Age differences in neural response to reward and loss in children
Authors: Gibb Brandon E. , Tsypes Aliona , Israel Elana , Owens Max
Published: March 2022

The goal of this study was to examine age‐related differences in children’s reward processing. Focusing on reward outcome processing, we used event‐related potentials to examine substages of neural response to gain versus loss feedback in a sample of 7–11‐year‐old children (M = 9.67, SD = 1.40) recruited from the community (N = 234; 47.6% girls, 66.2% non‐Hispanic European American). Using principal components analysis (PCA), we focused on temporospatial combinations that closely resembled the RewP, fb‐P3, and fb‐LPP in temporal and spatial distributions. Two of these, the PCA factors reflecting the RewP and fb‐LPP, demonstrated age‐related differences in response to gains versus losses. Age‐related changes in the RewP were specific to gain feedback, with RewP amplitudes to gain, but not loss, increasing from middle to late childhood. In contrast, age‐related changes in fb‐LPP were specific to loss feedback, with fb‐LPP amplitudes to losses, but not gains, decreasing from middle to late childhood. Follow‐up analyses revealed that children younger than age 8 exhibited larger fb‐LPP responses to loss than gain, whereas children older than age 10 exhibited larger RewP responses to gain than loss. Similar results were obtained using mean amplitude‐based ERP indices and the results do not appear to have been due to age‐related differences in the latency or location of the ERPs themselves. These results highlight the importance of examining distinct substages of reward outcome processing and suggest that robust neural responses to loss feedback may emerge earlier in childhood than responses to gains.
Structural insights into proteins from white spot syndrome virus: Perspectives on structure‐based anti‐viral strategies
Authors: Datta Aritreyee , Hossain Shaikh Nausad , Mohapatra Chinmayee , Vasudevan Dileep
Published: March 2022

White spot syndrome virus (WSSV) causes severe disease in crustaceans, specifically shrimp, leading to substantial economic losses to the aquaculture industry. Existing treatment methods fail to sufficiently curb the occurrence and spread of the disease, necessitating the development of effective control and treatment strategies. Structural studies have primarily focused on envelope proteins and a few non‐structural proteins involved in host entry, viral replication, viral assembly and host immune evasion, thus presenting themselves as potential drug targets. Here, we provide a comprehensive review of the insights gained from such structural elucidations to contribute to developing novel therapeutic strategies. In addition, we touch upon the current and future perspectives towards structure‐based drug or vaccine development against WSSV.
Self‐perceptions moderate the effect of implicit theories on preadolescent's attributions of their positive and negative social experiences
Authors: Commisso Melissa , Bukowski William M.
Published: March 2022

Associations between implicit theories of personality, perceived social competence, and attributions to explain positive and negative outcomes in social tasks were examined in a study of 103 fifth‐ and sixth‐grade girls and boys. Consistent with the basic model formulated by Dweck and Leggett (1988), it was hypothesized that having an entity, rather than an incremental, perspective would vary as a function of the degree to which children had a positive view of their social competence. The results showed that an entity theory of personality was associated with emphasis on the importance of personal characteristics and task difficulty following social failure, whereas an incremental theory was associated with emphasis on the importance of task ease following social success. High scores on the positive perceived social competence measure were associated with emphasis on the importance of personal characteristics, effort and task ease following social success and the importance of personal characteristics, luck and task difficulty following social failure. Preadolescents with an entity theory of personality were less likely to make attributions of personal characteristics and task difficulty to social failure if they had a positive view of their social competence. Preadolescents with an incremental theory of personality were not likely to make these attributions about social failure regardless of whether they viewed their social competencies as positive. These findings indicate that the association between entity and incremental views and social attributions needs to be considered in conjunction with perceptions of the self. They provided support for Deck and Leggett's (1988) model.
Safe handovers: Safe patients‐why good quality structured handovers in the transfusion laboratory are important
Authors: Tuckley Victoria , Davies Jennifer , Poles Debbi , Robbie Chris , Narayan Shruthi
Published: March 2022

Background

Effective transfer of information relating to patient care is vital in healthcare. In the UK formal handover is an established and well reported process in the clinical setting but less so in transfusion laboratories. Blood transfusions occur within many hospital specialities and across clinical and laboratory staff shifts, making robust handover critical for safe practice. Failure to adequately transfer information relating to pending or ongoing provision of blood components during shift handover in the laboratory can have an adverse impact on patient care.

Aims

To identify transfusion errors where laboratory handover was considered a contributory factor.

Materials and methods

Serious adverse events and reactions reported to the UK haemovigilance scheme, Serious Hazards of Transfusion (SHOT), involving handover in the transfusion laboratory were reviewed for a 6‐year period.

Results

Laboratory incidents involving handover were mainly associated with incorrect blood component transfused—specific requirements not met (IBCT‐SRNM) and delays in provision of blood components transfusion, with 16.6% of these cases involving major haemorrhage situations. Handover was found to be insufficient in most cases, no handover was completed in 29.5% of cases, inadequate written handover accounted for 14.8% cases, and inadequate verbal for 5.7% of cases.

Discussion

Poor handover can lead to laboratory errors, particularly delays in provision of blood components. Embedding effective handover processes in the laboratory and including handover time within the shift working pattern, may help reduce errors and ensure continuity of care.

Conclusion

Handover should be considered a task that is built into laboratory routine practices, ensuring effective transfer of information and appropriate follow up actions are taken. SHOT have created a handover template which can be adopted in laboratories to formalise this process.
Velocity Field Level Set Method Incorporating Topological Derivatives for Topology Optimization
Authors: Wang Yaguang , Yang Handong , Kang Zhan
Published: March 2022

The velocity field level set method constructs the velocity field by velocity design variables and basis functions, and thus facilitates the use of general optimizers while still retaining the level set-based implicit topological representation. This paper incorporates the topological derivative concept into the velocity field level set method to enable automatic nucleation of interior holes. In each design iteration, a specified volume fraction of new holes is inserted at locations with smaller values of topological derivatives. Thus, the method provides a way to directly change the structural topology during the boundary evolution using the velocity field based on the shape sensitivity. Compared with the original velocity field level set method, the current implementation can further accelerate the topological and shape evolution during the optimization process. More importantly, the capability of hole nucleation eliminates the need of prescribing initial holes and thus alleviates the dependency of the optimized design on the initial design. Several numerical examples in both 2D and 3D design domains are presented to demonstrate the validity and efficiency of the proposed method.
A General Theory and Analytical Solutions for Post-Buckling Behaviors of Thin Sheets
Authors: Zhang Jiawei , Qiu Xinghan , Wang Changguo , Liu Yuanpeng
Published: March 2022

A robust and general theory is of great importance to understanding the mechanism of wrinkling, describing its behaviors and guiding the design of thin sheets. Two widely accepted theories, tension-field theory (Wagner, 1929) and thin-film theory (Cerda and Mahadevan, 2003), have been successfully used in predicting the location and pattern of wrinkling and defining critical conditions for its onset, but they have failed to describe the post-buckling behaviors (i.e., bifurcations, increasing wavenumber, and corresponding changes in morphology). In this paper, we propose a new theory of wrinkling that considers the effects of both mechanical and geometrical characteristics of thin sheets on the spatial variation in wrinkles and is valid for the general problems of post-buckling analyses. By circumventing the Föppl–von Kármán equations, the theory offers a compelling complement to thin-film theory and provides analytical details of wrinkles, especially for closed form of post-buckling behaviors. An energy barrier is introduced to assess the configurational changes of wrinkles as they evolve. Three typical examples are selected for validating the robustness of the theory and exploring its implications. More broadly, the present work provides important guidelines for eliminating wrinkles in thin sheet structures.
Efficient Joining Sequence Variation Analysis of Stochastic Batch Assemblies
Authors: Tabar Roham Sadeghi , Lindkvist Lars , Wärmefjord Kristina , Söderberg Rikard
Published: March 2022

Geometric variation causes functional and aesthetic problems in the assemblies. The challenge is predicting the moments of the distribution of geometric deviations of assemblies to evaluate compliance with the set requirements. The joining operation, i.e., resistant spot welding (RSW), is one of the most crucial steps in the assembly process of nonrigid components, imposing forces on the parts and causes bending and deformation during the assembly, consequently contributing considerably to the final geometric outcome of the assembly. To model the behavior of the assembly realistically and achieve accurate simulation results, considering the sequence of joining is essential. In a digital twin of the assembly process, joining sequences need to be provided for the optimal geometric outcome of the batch of assemblies. The sequence optimization of the joining processes is a time-consuming combinatorial problem to solve. Variation analysis of nonrigid assemblies with stochastic part inputs, including optimal joining sequences, requires an extensive amount of the computational effort. More efficient approaches for evaluating assembly geometric variation are desired. In this article, a computationally efficient approach is proposed for geometric variation analysis and optimization of nonrigid assemblies with stochastic part inputs with respect to the RSW sequences. A clustering approach is proposed categorizing the incoming parts based on the part variation. Sequence optimization is performed, and geometric variation is analyzed for each cluster. The results show that the proposed method drastically reduces the computation time needed for sequence optimization compared to individualized optimization for each assembly.
Concise and Effective Network for 3D Human Modeling From Orthogonal Silhouettes
Authors: Liu Bin , Liu Xiuping , Yang Zhixin , Wang Charlie C. L.
Published: March 2022

In this article, we revisit the problem of 3D human modeling from two orthogonal silhouettes of individuals (i.e., front and side views). Different from our previous work (Wang et al. (2003, “Virtual Human Modeling From Photographs for Garment Industry,” Comput. Aided Des., 35, pp. 577–589).), a supervised learning approach based on the convolutional neural network (CNN) is investigated to solve the problem by establishing a mapping function that can effectively extract features from two silhouettes and fuse them into coefficients in the shape space of human bodies. A new CNN structure is proposed in our work to extract not only the discriminative features of front and side views but also their mixed features for the mapping function. 3D human models with high accuracy are synthesized from coefficients generated by the mapping function. Existing CNN approaches for 3D human modeling usually learn a large number of parameters (from 8.5 M to 355.4 M) from two binary images. Differently, we investigate a new network architecture and conduct the samples on silhouettes as the input. As a consequence, more accurate models can be generated by our network with only 2.4 M coefficients. The training of our network is conducted on samples obtained by augmenting a publicly accessible dataset. Learning transfer by using datasets with a smaller number of scanned models is applied to our network to enable the function of generating results with gender-oriented (or geographical) patterns.
Water Hammers Exploded the Nuclear Power Plants at Fukushima Daiichi
Authors: Leishear Robert A.
Published: March 2022

A fundamental contemporary theory, the Leishear explosion theory, explains major explosions at Three Mile Island and Fukushima Daiichi. Focusing on the Fukushima Daiichi explosions as well as many small nuclear power plant explosions, auto-ignited explosions hammered the largest seismic response at Unit 1 on Mar. 12, 2011. At Unit 3 on Mar. 14, a visibly larger explosion ignited with an observed fireball and smoke cloud but lower seismic forces. On Mar. 15, a Unit 2 reactor system explosion ignited hydrogen in the Unit 4 reactor building to cause damages following ignition, and seismic responses were negligible. Note that a Unit 2 reactor building explosion did not occur, and this fact is questionably attributed to the destructive removal of one of the walls of Unit 2 due to the earlier Unit 1 explosion. All of these explosions were ignited by fluid transients that exploded flammable hydrogen that was created during nuclear reactor core meltdowns, which were initiated by loss of power due to a tsunami. The conclusions presented here build upon earlier publications, where fluid transients auto-ignite hydrogen to explode buildings. In addition, research from Argonne National Laboratory provides background to explain this common cause for nuclear power plant explosions. Although different than the Argonne report conclusions, conclusions here are consistent with observations provided by the Argonne report. New ideas challenge existing beliefs, but the stakes are high since nuclear reactor safety is important to prevent loss of life and catastrophic environmental damages. The next nuclear power plant explosion can be stopped!
Efficient Neutron Irradiation Procedure for Uniform Dopant Distributions in Silicon Doping
Authors: Mohamed Nader M. A. , Osman Mosa , Abdelrazek Ibrahim
Published: March 2022

Neutron transmutation doping (NTD) is one of the several techniques used for n-type doping with good homogeneity. NTD performances were investigated in this work within a project funded by the Academy of Scientific Research and Technology (ASRT), Egypt, for the “production of doped Silicon Wafers for Solar Panels and Basic Electronics,” 2015–2018. The Egypt second research reactor (ETRR-2) has two irradiation positions for silicon doping using NTD. The two positions can accommodate silicon ingots with large diameters up to six inches. One crucial parameter that affects the quality of the product is the distribution of the dopant in the irradiated ingot. The irradiation facility provides the option of rotating the sample during irradiation for flattening the radial distribution of the dopant. Since the neutron flux is not flat along the irradiation position due to leakage and the effect of control rods, the generated dopant will be not flat along the axial direction. To overcome this problem, this paper proposed an irradiation procedure to smooth the dopant distribution along the axial direction. Such procedure can be applied for NTD facilities that has not an acceptable axial neutron flux distribution in silicon doping process. The procedure is based on loading the irradiation position by two ingots staked end to end and, at the middle of the irradiation duration, the two ingots swap their places. This strategy was verified by MCNP5 calculations and experimentally.
Coupled Heat Transfer Properties of Aluminum/Titanium Alloy Plates With Kerosene Active Cooling
Authors: Hu Guohao , Zhong Fengquan , Du Mengmeng , Wang Qinyang , Kang Honglin
Published: March 2022

Active cooling is an effective thermal protection method for plates under high thermal loading. In this paper, characteristics of coupled heat transfer of aluminum alloy and titanium alloy plates with kerosene active cooling are studied numerically and experimentally. The effects of cooling channel spacing as well as the inlet parameters of kerosene on the maximum temperature and temperature uniformity of the plate are investigated with varied heat fluxes. Besides, the thermal resistance and flow resistance of kerosene cooling are also analyzed. The experimental results show that the 2a12-type aluminum alloy plate can be cooled to a maximum temperature of 460 K with kerosene cooling under a mass flowrate of 24.7 g/s and heat flux of 6–11 kW/m2. The numerical results show that the maximum temperature is mainly affected by the channel spacing and heat flux. Compared to the titanium alloy plate, the aluminum alloy plate is more likely to be affected by the coolant mass flowrate. In addition, the conductive thermal resistance of aluminum alloy plates is 0.0017–0.0079 m2 K/W and is 0.015–0.073 m2 K/W for titanium alloy plates. For both materials, conductive thermal resistance dominates the total thermal resistance of plates with active cooling.
Investigations on the Cycle Performance of a Diffusion Absorption Heat Transformer Using HCOOK as an Alternative to LiBr
Authors: Wang Shikuan , Liu Yilun , Wang Qin
Published: March 2022

A diffusion absorption heat transformer (AHT) is very potential to improve energy utilization efficiency and reduce carbon emission, because it can be totally driven by waste heat without electricity consumption. On the base of a simulation model, the cycle performance of a diffusion absorption heat transformer using HCOOK-H2O-R134a-TEGDME and LiBr-H2O-R134a-TEGDME is compared under specified temperatures of Generator A, Generator B, evaporator, condenser, low-temperature (LT) absorber, and high-temperature (HT) absorber. The influences of six temperatures on cycle performance are assessed and coefficient of performance (COP) is found more sensitive to the temperatures of Generator B and high-temperature absorber. High COP corresponds to small diffusion gas supply ratio and small proportion of the heat input to Generator A in the total thermal power input. The employment of HCOOK instead of LiBr is beneficial to increasing COP in optimized conditions. In the design temperature conditions, COP can be increased from 0.170 to 0.178 in the system using HCOOK instead of LiBr. Meanwhile, diffusion gas supply ratio, proportion of the heat input to Generator A, and pumping ratio (PR) of Lifting Tube B can be decreased to 0.368, 0.022, and 0.098, respectively. The diffusion absorption heat transformer will provide a new way to lift the temperature of low-grade heat for more availability without electricity input and improve the energy utilization efficiency.
Comprehensive Numerical Analysis on Flow and Heat Transfer Characteristics of Printed Circuit Heat Exchanger With Fins
Authors: Lu Peng , Yang Qinshan , Wei Jian , Wu Peiyang , Huang Hulin
Published: March 2022

Printed circuit heat exchanger (PCHE), as a high-efficiency and compact heat exchanger, shows a high potential in high temperature, high pressure, and some extreme environments, thus, it is widely used in nuclear power generation, refrigeration, aerospace, etc. In this paper, the flow and heat transfer characteristics of heat transfer channels with different fins were numerically analyzed, by changing helium inlet temperature and mass flowrate. The results indicate that, with the increase of helium mass flowrate, Nusselt number and pressure loss grow, while Colburn factor and Fanning friction factor drop. As helium inlet temperature rises, Nusselt number, Colburn factor, and pressure loss grow, whereas Fanning friction factor decreases. In addition, the heat transfer characteristics of the channels with different fins are higher than that of the finless channel, among which the circular finned channel has the best heat transfer performance. In spite of a slightly degraded flow performance, the comprehensive performance of the finned channels is superior to that of the finless channel, and the elliptical finned channel has the best performance, followed by airfoil finned channel and circular finned channel.
Haptic Feedback for Virtual Reality Computer Aided Design
Authors: Springer Scott L. , Gadh Rajit
Published: March 2022

Many advances in computer aided design (CAD) have been made to support more rapid product development. One key area that has not been adequately addressed is in the area of rapid model creation for the exploration and communication of initial or conceptual design ideas. The human computer interface for current CAD systems remains tedious, detail oriented, and time consuming, and because of this CAD cannot be utilized effectively in the early stages of a design project. This is a considerable deficit, since the visualization of spatial models at the most crucial (concept) stage of design would be of great value. It is during this stage that most decisions controlling overall product performance limits are made. To address this need, a new approach to shape modeling has been proposed, which incorporates a virtual reality (VR) design interface. The initial interface specification includes multi-modal input/output consisting of speech input, auditory output, spatial (glove) input, and three dimensional stereographic display output.

It is desirable to augment this interface with an additional output mode in the form of haptic or touch sensation to more efficiently and intuitively interact with concept solid models. The hypothesis is that the addition of this output mode will (i) increase the efficiency in complex geometry creation, and (ii) aid in the understanding and exploration of a wide variety of design concepts. The desire for haptic feedback is shared by many developers of VR environments, for a wide variety of applications. Thus, there has been a recent increase in research interest in this area. The development of haptic feedback systems remains a multi-disciplinary challenge as an effective system must address perceptual, comfort, control, and mechanical issues that arise from the closely coupled human-machine dynamics present in a haptic feedback system. In this paper, we evaluate the general approaches for haptic feedback design in light of CAD tasks. Inherent limitations to the various approaches are identified and evaluated. The limitations are compared with the device complexity and value added for CAD operations.
Virtual Reality for Design and Machining Processes
Authors: Bzymek Zbigniew M. , Billatos Samir B.
Published: March 2022

Design engineers always look for attractive ways to demonstrate the concept of their designed systems. One of the techniques used in engineering is to draw or make physical model of the system. Computer graphics and virtual reality are new techniques that bring promising changes in this respect. The development of Virtual Machines and Virtual Machining Processes are technologies used in the design of machining equipment and in evaluating production processes. They consist of a group of recently developed techniques and approaches that allow the construction of machine computer models and the simulation of the fabrication process. What makes this group of manufacturing technologies special is that they allow the checking of machining and production parameters before actual prototyping and manufacturing of the required tooling. The possibility of using these virtual techniques could result in great savings of both time and money. In general, virtual manufacturing promises shorter design cycles with more design iterations, leading to a an optimal design and better use of resources. The end goal of any virtual manufacturing is to produce a virtual model of a machine that will virtually make the part from its database file containing the geometrical description of a physical object in terms of pre-defined geometric entities. The actual manufacturing hardware provides the physical means to machine the part, which Virtual Machining allows making as a computer model. A special software is employed to bridge the gap between the CAD data and the virtual manufacturing system. Such software should control various parameters such as the rate at which the positioning system proceeds, the tool path, the thickness of the layer of the material for removal and/or length of the path, the slice length, and others. Virtual manufacturing provides a means of motion control and easy manipulation of various manufacturing hardware. This paper describes our research effort to develop methods and software for virtual design that allow creation of different kinds of milling and grinding machines. These machines are compared with the actual existing machines and their production parts.
Concurrent Design, Analysis and Prototype of a High Pressure Optical Cell for Physico-Chemical Studies of Biological Systems
Authors: Zhou Jack G. , Ostrow Alan , Chong Parkson Lee-Gau
Published: March 2022

The commercially available high pressure optical cells, used in biological research, can only satisfy a limited range of experimental requirements. Current high pressure cell designs only allow for the measurement of single samples, thus limiting the data which researchers can obtain. We present a new design which enables users to introduce a second component to the original sample, while both components are under high pressure. This allows researchers to observe initial molecular interactions at high pressure via fiber optics and record data which was previously unobtainable. The design innovation which distinguishes the high pressure optical cell from existing models is the introduction of a laser-activated stopper system, which separates the two biological samples until the experimenter is ready to mix them. Concurrent Engineering methodologies and tools were used in conjunction with theoretical analysis to develop this innovative system. A high pressure cell prototype was built to further verify the new design and explore new challenges.
Optimizing Designs for Quality and Environmentally Responsible Manufacturing
Authors: Wells Wayne E.
Published: March 2022

Traditional economic analysis methods for manufacturing decisions include only the clearly identified and immediate cost and revenue streams. Quality and environmental issues have generally been seen as costs, in the form of wastes, material losses, inspections, rejects, compliance tests and pre-discharge treatments. The components of the waste stream, often purchased as raw materials, become liabilities at the “end of the pipe” and none of their intrinsic material value is recognized. Quality requirements have been seen as burdens placed on the system which constrain the manufacturer’s freedom of strategy for increasing profits, although recent evidence shows that firms are recognizing the value of improved quality systems.

A new mathematical treatment of manufacturing economics is proposed in which the costs of quality along with the costs for separation of the waste stream and costs of external quality problems are compared with the intrinsic value of the waste materials to show how their recovery can provide an economic advantage to the manufacturer. The model is based on the application of thermodynamic analysis to economic modeling. This paper describes the proposed model, and examines case studies in which the changed decision rules have yielded significant savings while protecting the environment. The premise proposed is that by including quality costs and the value of the waste materials in the profit objective of the firm and applying the appropriate technological solutions, manufacturing processes can approach closed systems in which losses are minimized and environmental problems are converted into economic savings.
A New Approach to Mold Design Using Manufacturable Entities
Authors: Krishnan Subramanian , Magrab Edward B.
Published: March 2022

A new approach using two process specific entities is presented for generating the shape of the mold for an injection molded part simultaneously as the part is being created. The user creates the part, and the mold is generated dynamically and transparently to the user. The mold is created using six stages of analysis; (1) the part is analyzed for undercuts based on the accessibility of the entities from the bottom most plane of the part to determine if the mold is either a two piece or a multi piece mold; (2) the number of mold pieces is determined from the number of undercuts and their locations; (3) the parting direction and the parting line for each mold piece are determined from the properties of a rectangular box surrounding each entity in the mold piece (called an extent) and from the properties of a vector field normal to the parting line; (4) the stock size is determined for each mold piece from the properties of the extents; (5) the process plan for machining each mold piece is determined; and (6) the complete mold is created by assembling all the mold pieces. It is demonstrated that using process specific entities simplifies the different stages of mold creation process. Furthermore, generating the process plan for each mold piece requires only arranging the entities to be machined in each mold piece based on their accessibility from the surface of its stock. It is demonstrated that by creating the mold incrementally after each stage of a part’s creation allows one to perform manufacturability evaluation of the part and the mold simultaneously. The advantages of our approach over the current methodologies for determining the mold from the part are enumerated.
Tolerance Analysis for Sheet Metal Assembly Using a Beam-Based Model
Authors: Ceglarek Dariusz J. , Shi Jianjun
Published: March 2022

The tolerance study is one of the most critical and neglected issues in sheet metal assembly manufacturing research. The fundamental shortcoming of currently existing tolerancing methods is the lack of physical significance of the model. This paper presents a new tolerance analysis methodology for sheet metal assembly based on physical/functional modeling of the fabrication error using the developed beam-based model. The modeling method includes principles of decoupling automotive parts into beam members, modeling of beam-to-beam joint geometry, and identification of part locating points. Tolerance analysis is conducted in three steps: (1) input of part and assembly tooling variability based on the statistical distribution; (2) calculation of accumulated tolerances for key process characteristics using statistical models; and (3) calculation of resultant tolerances based on the flexible beam-based model.
Disassembly Planning Analysis for Electromechanical Products
Authors: Kuo Tsai C. , Yu Steve Y. , Zhang Hong C.
Published: March 2022

It has been recognized that appropriate disassembly of used products is necessary in order to make recycling economically and environmentally viable in the current state of the art reprocessing technology. This paper describes a graph-based heuristic approach to automatically generate the disassembly planning for electromechanical products. The planning is divided into four stages, geometric assembly representation, cut-vertex search analysis, disassembly precedence matrix analysis, and disassembly sequences and plan generation. A personal computer is used to illustrate the example of disassembly sequences generation.
Evaluation of Composite Boat Manufacturing Processes With Green Quality Function Deployment (GQFD)
Authors: Jiang Shunliang , Han Kerang , Wang Ben , Zhang Chuck , Deshmukh Ahbijit
Published: March 2022

In today’s globally competitive market, design and manufacturing of ideal products that meet customer requirements, especially cost less and are environmental constraints has become the goal for most manufacturing organizations. In this paper, a technique that can aid designers to achieve this goal, namely Green Quality Function Deployment (GQFD), is introduced. Based on the analysis of the different processes for manufacturing of composite boats, the GQFD is used to evaluate each process by examining the sub-processes. With this technique, the best process for manufacturing of composite boats was selected.
Bungee Cord Danger Analysis
Authors: Brickman Dennis B. , Barnett Ralph L.
Published: March 2022

The utility of bungee cords is so persistently attractive that they continue to gain in popularity. Unfortunately, one of the characteristics of bungee cords is the sudden release of stored energy which results from opening of hooks, failure of the bungee cord and hook connection, inadvertent release of the bungee cord during application, and failure of the structure receiving the hook. Each of these failure modes allows the free end of the bungee cord to attain high speeds which produce injuries through impact. The design of personal protection equipment and the evaluation of the danger level related to a released bungee cord require information on hook speed. This paper presents a first order analysis of the maximum attainable speed.
Hand Motion During Trip and Fall Scenarios
Authors: Barnett Ralph L. , Glowiak Suzanne A.
Published: March 2022

The location of workplace hazards, the design of fall intervention systems, the development of climbing and walking strategies, and the forensic analysis of slip and fall accidents all benefit from a knowledge of hand motion under the combined effects of gravity and human response. This paper calculates the maximum simple reaction time that will enable the hands to elevate during a drop or trip event. Hand trajectories are characterized for both scenarios.