Comparing finite element and meshfree particle formulations for projectile penetration into fiber reinforced concrete

James O’Daniel,Mark Adley,Kent Danielson,Beverly DiPaolo,Nicholas Boone 사단법인 한국계산역학회 2010 Computers and Concrete, An International Journal Vol.7 No.2

Penetration of a fragment-like projectile into Fiber Reinforced Concrete (FRC) was simulated using finite element (FE) and particle formulations. Extreme deformations and failure of the material during the penetration event were modeled with multiple approaches to evaluate how well each represented the actual physics of the penetration process and compared to experimental data. A Fragment Simulating Projectile (FSP) normally impacting a flat, square plate of FRC was modeled using two target thicknesses to examine the different levels of damage. The thinner plate was perforated by the FSP, while the thicker plate captured the FSP and only allowed penetration part way through the thickness. Full three dimensional simulations were performed, so the capability was present for non-symmetric FRC behavior and possible projectile rotation in all directions. These calculations assessed the ability of the finite element and particle formulations to calculate penetration response while assessing criteria necessary to perform the computations. The numerical code EPIC contains the element and particle formulations, as well as the explicit methodology and constitutive models, needed to perform these simulations.

Kazakhstan’s Quest for Status: A Secondary State’s Strategy to Shape Its International Image

O'Neill Daniel C.,Primiano Christopher B. 한양대학교 아태지역연구센터 2024 Journal of Eurasian Studies Vol.15 No.1

Since becoming an independent country in 1991, Kazakhstan has demonstrated a strong desire for international status and recognition by, for example, hosting numerous international events, such as chairing the OSCE and hosting EXPO 2017; creating the Conference on Interaction and Confidence Building Measures in Asia; and, most notably, presenting the abandonment of its nuclear weapons as a model for other states to emulate. Surprisingly, Kazakhstan has received scant attention by scholars regarding its desire for status, especially considering how the government has framed its decision to relinquish its nuclear weapons in terms of advancing international peace at the expense of its own security self-interest. Kazakhstan’s status-seeking raises two questions. First, how can a mid-level power strategically frame its foreign and domestic policies in order to improve its global status? And second, how can it improve its international status when domestic priorities (such as economic development and political stability) lead to policies that meet disapproval abroad? In this article, we answer these questions by examining issue areas (security, democratization, and the environment) that contain variation in our dependent variable, Kazakhstan’s quest for status. In doing so, we reveal patterns of how a secondary or mid-level state lacking substantial material capabilities can, through its words and actions, construct an image that may enhance its international status. We also show variation by issue area in the reception of these efforts by developed and developing countries. Lastly, we reveal in what issue areas Kazakhstan’s desire for status internationally is constrained by the government’s desire to maintain power domestically.

Preoperative prediction of the size of pure ductal carcinoma in situ using three imaging modalities as compared to histopathological size: does magnetic resonance imaging add value?

Daniel, O. K.,Lim, S. M.,Kim, J. H.,Park, H. S.,Park, S.,Kim, S. I. Springer Science + Business Media 2017 Breast cancer research and treatment Vol.164 No.2

<P>MRI is better at estimation of histopathological DCIS size compared with mammography. However, ultrasonography had better estimation compared with MRI and mammography, probably owing to the high breast density in this population.</P>

Lens culinaris: A New Biocatalyst for Reducing Carbonyl and Nitro Groups

Daniele Alves Ferreira,Robério Costa da Silva,João Carlos da Costa Assunção,Marcos Carlos de Mattos,Telma Leda Gomes de Lemos,Francisco José Queiroz Monte 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.2

A series of aliphatic and aromatic aldehydes and ketones, as well as some nitrocompounds were reduced using whole plant cells from Lens culinaris seeds. In addition, we also investigated the possibility of enzymatic ester hydrolysis to explore the potential of these seeds. The reduced ketones products were obtained in yields of 8 ~82% and enantiomeric excess of 39 ~ 75%. Aldehydes were more reactive than ketones with high chemical yield (95→99%), whereas the aromatic nitrocompounds showed low (2%) to high (> 99%) conversion depending upon the nature and position of the aromatic ring substituents. Ester hydrolysis by the Lens culinaris was quite effective with the ester p-nitrophenyl acetate (> 99% conversion).

Commercial synthetic hydrotalcite as an adsorbent nanomaterial for removal of bacteria from contaminated water

Anastasiya V. Sidarenka,Sviatlana I. Leanovich,Emiliya I. Kalamiyets,Daniel E.L. Vieira,João P.V. Cardoso,João Tedim,Andrei N. Salak 대한환경공학회 2023 Environmental Engineering Research Vol.28 No.3

Layered double hydroxides (LDHs) are regarded as potential adsorbents for water treatment from a wide range of pollutants. However, there are only a few studies concerning application of LDHs for elimination of microorganisms from aquatic systems. In this work, experiments were conducted to investigate the efficiency of commercial synthetic hydrotalcite Mg6Al2(CO3)(OH)16·4H2O as an adsorbent for water purification from fecal indicator bacteria Escherichia coli BIM B-378 and Enterococcus faecalis BIM B-1530. Our findings indicate that exposure for 4 h to hydrotalcite (5 g/L) in suspension resulted in the removal of about 40% of coliforms and 25% of enterococci from water, at a high bacterial load (2×1010 CFU/L), and the removal efficiency of E. coli and E. faecalis did not significantly change when both bacteria were present in water. In addition, the percentage of removed bacteria increased with increasing of hydrotalcite concentration in the suspension (0.5 to 10 g/L), contact time (1–7 h) and decrease of pH (5.5), and decreased at low incubation temperature (16°C). Finally, hydrotalcite did not exhibit bactericidal activity and retention of bacteria was found to be reversible. Therefore, our findings suggest that commercial synthetic hydrotalcite could be potentially used in technologies of water treatment from bacterial contamination.

Reactivity of hydroxyl radicals with neonicotinoid insecticides: mechanism and changes in toxicity

Dell'Arciprete, Maria L.,Santos-Juanes, Lucas,Sanz, Antonio Arques,Vicente, Rafael,Amat, Ana M.,Furlong, Jorge P.,Martirea, Daniel O.,Gonzalez, Monica C. Korean Society of Photoscience 2009 Photochemical & photobiological sciences Vol.8 No.7

The reactivity of hydroxyl radicals ($HO^{\cdot}$) towards three neonicotonoid insecticides, namely imidacloprid, thiacloprid and acetamiprid was investigated. These radicals were generated by photolysis of $H_2O_2$ solutions. Flash photolysis experiments were used to determine the rate constants of $5.5{\times}10^{10}M^{-1}s{-1}$, $6{\times}10^{10}M^{-1}s^{-1}$, and $7.5{\times}10^{10}M^{-1}s^{-1}$, for the reactions of $HO^{\cdot}$ with acetamiprid, imidacloprid, and thiacloprid, respectively. Continuous irradiation experiments in the absence and presence of $H_2O_2$ allowed the identification and toxicity evaluation of the primary photo- and oxidation products of the insecticides. In all cases, the less toxic 6-chloronicotinic acid was found to be the major product at higher degrees of oxidation. The results reported here indicate that the half life of the insecticides due to their reaction with $HO^{\cdot}$ radicals in natural aquatic reservoirs may vary between 5 h and 19 days, and therefore the hydroxyl radical-mediated oxidation may be a significant abiotic elimination route. However, elimination of the insecticide under such conditions might not improve the quality of the contaminated water, as the primary products of degradation still show considerable toxicity to Vibrio fischeri assays.

International regulatory requirements for skin sensitization testing

Daniel, Amber B.,Strickland, Judy,Allen, David,Casati, Silvia,Zuang, Valé,rie,Barroso, Joã,o,Whelan, Maurice,Ré,gimbald-Krnel, M.J.,Kojima, Hajime,Nishikawa, Akiyoshi,Park, Hye-Kyung Elsevier 2018 Regulatory toxicology and pharmacology Vol.95 No.-

<P><B>Abstract</B></P> <P>Skin sensitization test data are required or considered by chemical regulation authorities around the world. These data are used to develop product hazard labeling for the protection of consumers or workers and to assess risks from exposure to skin-sensitizing chemicals. To identify opportunities for regulatory uses of non-animal replacements for skin sensitization tests, the needs and uses for skin sensitization test data must first be clarified. Thus, we reviewed skin sensitization testing requirements for seven countries or regions that are represented in the International Cooperation on Alternative Test Methods (ICATM). We noted the type of skin sensitization data required for each chemical sector and whether these data were used in a hazard classification, potency classification, or risk assessment context; the preferred tests; and whether alternative non-animal tests were acceptable. An understanding of national and regional regulatory requirements for skin sensitization testing will inform the development of ICATM's international strategy for the acceptance and implementation of non-animal alternatives to assess the health hazards and risks associated with potential skin sensitizers.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We reviewed regulatory requirements for skin sensitization testing, by chemical sector, of seven countries or regions. </LI> <LI> This review summarizes data needs for hazard classification, potency classification, and risk assessment. </LI> <LI> We identify preferred test methods and note whether non-animal alternative test methods are acceptable. </LI> <LI> This effort will inform an international strategy for implementing non-animal approaches for skin sensitization assessment. </LI> </UL> </P>

Effect of the restorative technique on load-bearing capacity, cusp deflection, and stress distribution of endodontically-treated premolars with MOD restoration

Daniel Maranha da Rocha,João Paulo Mendes Tribst,Pietro Ausiello,Amanda Maria de Oliveira Dal Piva,Milena Cerqueira da Rocha,Rebeca Di Nicoló,Alexandre Luiz Souto Borges 대한치과보존학회 2019 Restorative Dentistry & Endodontics Vol.44 No.3

Objectives: To evaluate the influence of the restorative technique on the mechanical response of endodontically-treated upper premolars with mesio-occluso-distal (MOD) cavity. Materials and Methods: Forty-eight premolars received MOD preparation (4 groups, n = 12) with different restorative techniques: glass ionomer cement + composite resin (the GIC group), a metallic post + composite resin (the MP group), a fiberglass post + composite resin (the FGP group), or no endodontic treatment + restoration with composite resin (the CR group). Cusp strain and load-bearing capacity were evaluated. One-way analysis of variance and the Tukey test were used with α = 5%. Finite element analysis (FEA) was used to calculate displacement and tensile stress for the teeth and restorations. Results: MP showed the highest cusp (p = 0.027) deflection (24.28 ± 5.09 µm/µm), followed by FGP (20.61 ± 5.05 µm/µm), CR (17.72 ± 6.32 µm/µm), and GIC (17.62 ± 7.00 µm/µm). For load-bearing, CR (38.89 ± 3.24 N) showed the highest, followed by GIC (37.51 ± 6.69 N), FGP (29.80 ± 10.03 N), and MP (18.41 ± 4.15 N) (p = 0.001) value. FEA showed similar behavior in the restorations in all groups, while MP showed the highest stress concentration in the tooth and post. Conclusions: There is no mechanical advantage in using intraradicular posts for endodontically-treated premolars requiring MOD restoration. Filling the pulp chamber with GIC and restoring the tooth with only CR showed the most promising results for cusp deflection, failure load, and stress distribution.

Surgical Treatment of Acetabular Posterior Wall Fracture with Hip Arthroscopy: A Case Report

João Vale,Sara Diniz,Pedro Santos Leite,Daniel Soares 대한고관절학회 2022 Hip and Pelvis Vol.34 No.1

Posterior wall fractures are the most common type of acetabular fractures. Treatment can be conservative or surgical. Operative treatment is indicated for acetabular fractures that result in hip joint instability and/or incongruity, as well injuries with incarceration of fragments of bone or soft tissue within the hip joint. Surgical treatment can range from open reduction and osteosynthesis to hip arthroplasty. Arthroscopy has recently been used as the main surgical technique or as a reduction aid. In this case a 26-year-old male with a fracture of the posterior wall who underwent a posterior miniinvasive approach, followed by hip arthroscopy. This allowed joint wash, removal of the loose body, confirmation of reduction and absence of intra-articular hardware. Excellent clinical and radiological results were obtained. This case demonstrates the advantage of using hip arthroscopy in assessment of fracture reduction, the absence of intra-articular hardware or fragments, as well as a less invasive approach.

Botulinum Toxin Therapy versus Anterior Belly of Digastric Transfer in the Management of Marginal Mandibular Branch of the Facial Nerve Palsy: A Patient Satisfaction Survey

Daniel P Butler,,Jo I Leckenby,Ben H Miranda,Adriaan O Grobbelaar 대한성형외과학회 2015 Archives of Plastic Surgery Vol.42 No.6

Background Botulinum toxin (BT) chemodenervation and anterior belly of digastric muscle (ABD) transfer are both treatment options in the management of an isolated marginal mandibular branch of the facial nerve (MMB) palsy. We compare the patient satisfaction following either BT injections or ABD transfer in the management of their isolated MMB palsy. Methods Patients in the ABD-arm of the study were identified retrospectively from September 2007 to July 2014. The patients in the BT-arm of the study were identified prospectively from those attending the clinic. Both groups of patients completed a validated patient satisfaction survey. Statistical analysis was performed and a P-value <0.05 was considered statistically significant. Results Seven patients were in the ABD-arm and 11 patients in the BT-arm of the study. The patient satisfaction in both groups was high with 45% of ABD-arm patients and 40% of BTarm patients rating their overall outcome as ‘better’ or ‘much better’, which was significantly more than the proportion rating their outcome as ‘worse’ or ‘much worse’ (P<0.001), although there was a significant trend towards those in the ABD-arm being more likely to be dissatisfied with their outcome (P=0.01). Conclusions BT therapy is a good first-line intervention in the management of isolated MMB palsy. We have, however, shown that the overall satisfaction in both groups is high. Therefore, in patients who would prefer a more permanent solution to manage their facial asymmetry, ABD transfer remains a satisfactory treatment option with a good level of patient satisfaction.