bluuebunny/crossref_metadata_2025 huggingface dataset:
An accurate determination of the acceleration of gravity g in the undergraduate laboratory
Authors: Dupré A. , Janssen P.
Published: July 2002

A rod, connected with a horizontal hinge to the vertical axle of a motor, will deviate from the vertical at angular frequencies of the motor above a certain minimum value. The acceleration of gravity is related in a simple way to the speed of the motor, the length of the rod, and its angle with the vertical. It turns out that g can be measured in this way with an accuracy of about 0.1% without the use of sophisticated technology or the application of corrections to the result. The system has some other interesting features which make it particularly appropriate for the undergraduate laboratory.
Three-dimensional vocal tract imaging and formant structure: Varying vocal register, pitch, and loudness
Authors: Tom Kenneth , Titze Ingo R. , Hoffman Eric A. , Story Brad H.
Published: July 2002

Although advances in techniques for image acquisition and analysis have facilitated the direct measurement of three-dimensional vocal tract air space shapes associated with specific speech phonemes, little information is available with regard to changes in three-dimensional (3-D) vocal tract shape as a function of vocal register, pitch, and loudness. In this study, 3-D images of the vocal tract during falsetto and chest register phonations at various pitch and loudness conditions were obtained using electron beam computed tomography (EBCT). Detailed measurements and differences in vocal tract configuration and formant characteristics derived from the eight measured vocal tract shapes are reported.
Radiation impedance of a finite circular piston on a viscoelastic half-space with application to medical diagnosis
Authors: Zhang X. , Royston T. J. , Mansy H. A. , Sandler R. H.
Published: July 2002

In a recent study a new analytical solution was developed and validated experimentally for the problem of surface wave generation on a linear viscoelastic half-space by a rigid circular disk located on the surface and oscillating normal to it. The results of that study suggested that, for the low audible frequency range, some previously reported values of shear viscosity for soft biological tissues may be inaccurate. Those values were determined by matching radiation impedance measurements with theoretical calculations reported previously. In the current study, the sensitivity to shear viscoelastic material constants of theoretical solutions for radiation impedance and surface wave motion are compared. Theoretical solutions are also compared to experimental measurements and numerical results from finite-element analysis. It is found that, while prior theoretical solutions for radiation impedance are accurate, use of such measurements to estimate shear viscoelastic constants is not as precise as the use of surface wave measurements.
Anisotropy of the apparent frequency dependence of backscatter in formalin fixed human myocardium
Authors: Hall Christopher S. , Verdonk Edward D. , Wickline Samuel A. , Perez Julio E. , Miller James G.
Published: July 2002

Measurements of the frequency dependence of ultrasonic backscatter are presented for specific angles of insonification for regions of infarcted and noninfarcted human myocardium. A 5-MHz transducer was used to insonify cylindrical cores taken from 7 noninfarcted regions and 12 infarcted regions of the left ventricular free wall of 6 formalin-fixed human hearts explanted because of ischemic cardiomyopathy. The dependence of apparent (uncompensated for diffraction effects and attenuation) backscatter on frequency was approximated by a power-law dependence, |B(f)|2=afn. Under ideal conditions in a lossless medium, the effect of not compensating for the effects of diffraction and attenuation leads to the value of n to be 2.0 for Rayleigh scatterers while the frequency dependence of the fully compensated backscatter coefficient would be f4. The value of n was determined over the frequency range, 3–7 MHz. Both noninfarcted and infarcted myocardium exhibited anisotropy of the frequency dependence of backscatter, with maxima occurring at angles that were perpendicular to the predominant myofiber direction and minima when parallel to the fibers. Perpendicular insonification yielded results for n of 1.8±0.1 for noninfarcted myocardium and 1.2±0.1 for infarcted myocardium while parallel insonification yielded results of 0.4±0.1 for noninfarcted and 0.0±0.1 for infarcted myocardium. The functional form of the angle-dependent backscatter is similar for both noninfarcted and infarcted myocardium, although the frequency dependence is clearly different for both tissue states for all angles of insonification. The results of this study indicate that the anisotropy of the frequency dependence of backscatter may play a significant role in ultrasonic imaging and is an important consideration for ultrasonic tissue characterization in myocardium.
Intraspeech spread of masking in normal-hearing and hearing-impaired listeners
Authors: Summers Van , Leek Marjorie R.
Published: July 2002

Hearing-impaired and normal-hearing listeners labeled synthetic consonant-vowel stimuli (/bɑ/, /dɑ/, /gɑ/, /be/, /de/, /ge/) presented at moderate and high signal levels. First formant (F1) regions were synthesized at normal and at attenuated levels to test whether F1 attenuation might reduce upward spread of masking, making information contained in higher formant regions more available. Performance was tested in quiet and in broadband noise sufficient to mask initial release bursts. Although complete removal of F1 consistently reduced performance, F1 attenuation of up to 18 dB led to increased labeling accuracy, particularly in the /ɑ/ vowel context. Benefit associated with F1 attenuation was more consistently seen for hearing-impaired than for normal-hearing listeners and, in particular, for listeners with steep increases in audiometric thresholds between the first and second formant regions of the test stimuli. The availability of initial bursts as a source of place cues during testing in quiet did not reduce the benefit associated with F1 attenuation.
On the low-frequency oscillation of a fluid layer between two elastic plates
Authors: Hassan Waled , Nagy Peter B.
Published: July 2002

In 1965, Lloyd and Redwood predicted the existence of a new guided mode of wave propagation in solid–fluid–solid trilayers [Acustica 16, 169–173 (1965)]. In this so-called fluid mode, the two solid plates flex sideways in a symmetric way while the fluid in the thin gap between them is squeezed forward and backward parallel to the direction of wave propagation. This mode is slower than the lowest-order bending mode of the plates and asymptotically approaches the Stoneley–Scholte mode of the solid–fluid interface at high frequencies. While the other modes of the solid–fluid–solid trilayer are very similar to the free vibrations of the free solid plates which are only slightly perturbed by the fluid coupling between the plates, the fluid mode cannot be related to any classical Lamb mode in the plates. It is shown in this paper that at low frequencies the fluid mode is truly a coupled vibration of the solid and the fluid, which contribute the stiffness and the inertia, respectively. The highly dispersive phase velocity of this mode was measured over a frequency range of one decade by using a laser interferometric technique. The experimental results were found to be in good quantitative agreement with the theoretical predictions. To the best of our knowledge, these measurements constitute the first conclusive experimental evidence of the existence of the dispersive fluid mode predicted by Lloyd and Redwood.
Vertical profiles and horizontal scales of bubble clouds in the surf zone as measured with a distributed array of upward-looking sonars
Authors: Dahl Peter H. , Caruthers Jerald W. , Stanic Stephen J.
Published: July 2002

A collaborative, multi-institute experiment was recently performed in the vicinity of the Scripps Pier, whose goal was the study of bubble-field generation, transport, and distribution, as influenced by surf zone conditions. The collaboration produced an ensemble of instrumentation at the site for measuring bubbles, ambient noise, temperature and salinity, currents, and surface waves. This paper emphasizes data gathered by APL-UW using a set of four upward-looking transducers (frequency 240 kHz), which simultaneously measured vertical profiles of acoustic volume scattering from bubbles from four locations. The primary locus of measurement activity was defined by NRL-SSC’s triangular frame (Delta Frame) and the four transducer locations for the APL-UW system bracketed this region. The transport of bubbles via rip currents emerged as a key feature surf zone bubble environment. Images of volumetric backscattering strength versus time and depth reveal episodic events (by way of increased scattering level) which last O(100) s and can occur in intervals of O(10) min. Time lags for increased scattering at the four locations were consistent with a seaward flow of rip currents equal to ∼0.25 m/s. Other features of the data that complement the single-depth measurements made from the Delta Frame will be discussed. [Work supported by ONR.]
Reverberation time predictions using neural network analysis
Authors: Nannariello Joseph , Fricke Fergus
Published: July 2002

The study aims to utilize neural network analysis to develop a method to predict the reverberation time for enclosures—in the low and mid frequencies—by using neural networks that have been trained with constructional and acoustical data. The study begins with the hypothesis that, in practice, reverberation time predictions are too difficult to undertake using existing computer models, and too inaccurate when using other methods. Specifically, the study aims at providing an expeditious and accurate method of predicting the reverberation time of enclosures at the initial design stage. To substantiate the hypothesis, and to bring into effect the aims of the study, assessments are made of the predictive powers of the trained neural networks. The results of the investigations have indicated that there is a good basis for using trained neural networks to predict the reverberation time for enclosures. The results have also shown that neural network analysis can identify those variables that have an effect on the predicted reverberation times.
Sinuous instability of a planar air jet: Propagation parameters and acoustic excitation
Authors: Nolle A. W.
Published: July 2002

The sinuous instability wave of a planar air jet is excited by localized acoustic flow across the nozzle. Phase velocity and the growth exponent are found from synchronous hot-wire measurements made beyond the excited region, where the profile is approximately sech-squared. In the observed range of scaled radian frequency, 0.02–1.33 (the stability limit), results agree with real-frequency (spatially growing) analysis but not with complex-frequency (temporally growing) analysis. The latter predicts smaller phase velocity at low frequencies and has been questioned in edgetone analysis. In further tests, the acoustic driving signal is made independent of downstream distance, as in an organ pipe. The jet deflection is then the sum of acoustic convection and of the instability wave, summing to zero at the nozzle, as proposed by Fletcher, Elder, and others. The instability-wave theory applies to linear behavior in the inviscid limit and therefore to a hypothetical nonspreading jet. The local velocity profile width must be considered in relating to a physical jet. In a flue organ pipe oscillating at equilibrium amplitude the stability-wave theory is not applicable near the lip, where the laminar flow assumed in the theory disappears and the jet deflection exceeds the range of linear behavior. Direct sound generation by the jet is investigated briefly.
Active control of automobile cabin noise with advanced speakers
Authors: Couche Jerome C. , Charette Francois , Fuller Chris R.
Published: July 2002

The purpose of this presentation is to demonstrate the application of active control of engine noise in the interior cabin of a sport utility vehicle with advanced, compact piezoelectric sound sources. A broadband feedforward filtered-X LMS algorithm has been used to achieve this goal. Preliminary tests have been conducted using arrangements of up to four commercially available speakers and four microphones. Various reference signals have been studied and these configurations show good results; attenuation of 7 dB at the error sensors has been measured in the 40–500 Hz frequency band and the dimensions of the zone of quiet generated by the control has also been measured. The ultimate goal of the research is the implementation of the active noise control with a new generation of speakers. These speakers use piezoelectric devices to induce the displacement of a speaker membrane, which radiates sound. Their main advantages are weight and dimensions, which are significantly smaller than conventional speakers are. [Work supported by MSI/ONR.]
Spontaneous otoacoustic emissions in heterosexuals, homosexuals, and bisexuals
Authors: McFadden Dennis , Pasanen Edward G.
Published: July 2002

Click-evoked otoacoustic emissions (CEOAEs) were previously shown to be significantly less strong in homosexual and bisexual females than in heterosexual females. Here it is reported that the spontaneous otoacoustic emissions (SOAEs) of those same 60 homosexual and bisexual females were less numerous and weaker than those in 57 heterosexual females. That is, the SOAEs of the homosexual and bisexual females were intermediate to those of heterosexual females and heterosexual males. The SOAE and CEOAE data both suggest that the cochleas of homosexual and bisexual females have been partially masculinized, possibly as part of some prenatal processes that also masculinized whatever brain structures are responsible for sexual orientation. For males of all sexual orientation, the SOAEs were less numerous and weaker than for the females, and there were no significant differences among the 56 heterosexual, 51 homosexual, and 11 bisexual males. All subjects passed a hearing screening test. When all SOAEs above 3000 Hz were excluded (as a control against incipient, undetected hearing loss) the same results were obtained as with the full range of data (550–9000 Hz). The differential use of oral contraceptives by the heterosexual and nonheterosexual females also could not explain the differences in their OAEs.
Scattering of a plane acoustic wave from a transversely isotropic cylinder encased in a solid elastic medium
Authors: Fan Y. , Sinclair A. N. , Honarvar F.
Published: July 2002

A mathematical model is developed to describe the scattering of a plane wave incident at an arbitrary angle on a transversely isotropic cylinder embedded in a solid elastic matrix. The model is based on the normal-mode expansion method, but is complicated by the coupling between the potential functions representing compressional and axially polarized shear waves. The solid matrix around the cylinder precludes the appearance of the leaky Rayleigh modes that dominate the spectrum of a cylinder immersed in a fluid. Instead, interfacial modes contribute to the scattered spectrum—these modes could be instrumental in the development of a nondestructive evaluation technique for the matrix-to-fiber bonds in a fiber-reinforced composite material. The presence of a solid matrix that supports shearing action leads to scattered compressional waves, and shear waves with polarization components in both the axial direction and r-θ planes. The sensitivity of resonances in each of these scattered wave components to perturbations in the cylinder's elastic constants is explored; results indicate that a judicious selection of resonance modes allows characterization of the cylinder's elastic properties.
Polystyrene Master Flow Curves
Authors: Chee K. K. , Rudin Alfred
Published: July 2002

Capillary extrusion flow curves of four anionic and five polydisperse polystyrenes have been measured at five temperatures between 170 and 237°C. The non-Newtonian flow curves of the narrow distribution polymers can be represented by a common master curve in terms of the viscosity ratio (η/η0) and the product of shear rate and a relaxation time. The polydisperse polymers do not yield a single flow curve. Current molecular and semiempirical models do not yield master curves which fit the experimental plots. Exceptions are Pao's model for monodisperse polymers and an empirical relation presented in this article which fits the data of the five commercial polymers studied. The existence of a general theory which represents experimental polymer flow curves satisfactorily has yet to be demonstrated. An acceptable model should predict rheological parameters correctly and should also show why experimental data for polymer melts scatter rather severely. Such scatter often reflects lack of control of an important experimental parameter and it is suggested that this parameter may be connected with differences in the physical significance of various estimates of zero shear viscosity, η0. Shear history of the samples may also be an important factor.
Shear induced gelation of colloidal dispersions
Authors: Cabane B. , Wong K. , Lindner P. , Lafuma F.
Published: July 2002

Nanometric silica particles, dispersed in water, have been bridged into long necklaces by adsorbing macromolecules of poly(ethylene oxide). At high coverage of particles by macromolecules the necklaces repel each other and the dispersions are homogeneous solutions; at low coverage the necklaces bind to each other and a concentrated phase separates from excess water. It is reported here that shear induced gelation and shear induced flocculation are observed near the boundary of the phase separation region. The structures of these dispersions under shear have been observed through small angle neutron scattering. It has been found that, above a critical shear rate, the necklaces connect to each other to form threadlike objects which align along the velocity. At higher shear these objects associate sideways to form three-dimensional flocs.
Comparison of diffraction intensity using a monocapillary optic and pinhole collimators in a microdiffractometer with a curved image-plate
Authors: Schields Paul J. , Ponomarev Igor Yu. , Gao Ning , Ortega Richard B.
Published: July 2002

The performance of a tapered, monocapillary optic was compared to double-pinhole optics by measuring the intensity and widths of powder diffraction peaks generated using Cr Kα and Cu Kα X-rays (46 kV, 46 mA). A microdiffractometer and curved image-plate system was used to collect diffraction patterns displayed by an alumina intensity standard. A monocapillary optic with a 20 μm beam width (measured at half the maximum intensity, FWHM) was compared to collimating pinhole optics with two apertures: one with 30 μm diameter pinholes and another with 50 μm pinholes. The average, integrated intensity of the diffraction peaks in the patterns collected using the 20 μm monocapillary optic was 6 to 7 times greater than the average diffraction intensity obtained with the 50 μm pinhole collimator and 25 times greater than the intensity obtained with the 30 μm collimator. The average increase in the FWHM of the diffraction peaks in the patterns obtained with the monocapillary optic was ∼2 times greater than the pinhole collimators.
New Guidance From the American Academy of Pediatrics on Protecting Children From Sexual Abuse in Health Care Settings
Authors: Suran Melissa
Published: September 2022

This Medical News article discusses a new policy statement from the American Academy of Pediatrics on preventing and responding to pediatric sexual abuse in health care settings.
Loneliness and social support as key contributors to burnout among Canadians workers in the third wave of the COVID-19 pandemic: A cross-sectional study
Authors: Card Kiffer G , Bodner Aidan , Li Richard , Lail Simran , Aran Niloufar , Grewal Ashmita , Skakoon-Sparling Shayna
Published: September 2022

Objective

COVID-19 has dramatically affected Western Society's relationship with work and contributed to increased worker burnout. Existing studies on burnout have mostly emphasized workplace culture, leadership, and employee engagement as key contributors to burnout. In this cross-sectional study, we examine the associations between Malach-Pines Short Burnout Measure (MPSBM) scores and participant's self reported personal characteristics, financial strain, workplace conditions, work-life balance, and social inclusion among Canadians living during the third wave of the COVID-19 pandemic.

Methods

To identify the most salient correlates of burnout, Canadian residents, aged 16+, were recruited using paid social media advertisements in French and English to complete a cross-sectional study. Multivariable linear regression and dominance analysis identified the most salient correlates of MPSBM scores. Exposure variables included demographic factors, financial strain, workplace conditions, work-life balance, social support, and loneliness.

Results

Among 486 participants, family social support (adjusted β = −0.14, 95%CI = −0.23, −0.05), emotional loneliness (adjusted β = 0.26, 95% CI = 0.18, 0.35), insufficient sleep (adjusted β = 0.38, 95% CI = 0.16, 0.60) and “me time” (adjusted β = 0.22, 95% CI = 0.03, 0.42), and indicators of financial security (e.g., owning vs renting; adjusted β = −0.36, 95% CI = −0.54, −0.17; insufficient pay: adjusted β = −0.36, 95% CI = −0.54, −0.17) were key burnout indicators. People with a bachelor's degree (vs ≤high school diploma; adjusted β = 0.29, 95% CI = 0.01, 0.58) also had higher burnout scores.

Conclusion

Interventions addressing workplace culture, leadership, and other proximal workplace stressors, while important, are likely insufficient to meet the needs of workers. Our findings suggest that broader, holistic multicomponent approaches that address multiple upstream dimensions of health—including mental health—are likely necessary to prevent and reduce burnout.
Biologics‐Loaded Photothermally Dissolvable Hyaluronic Acid Microneedle Patch for Psoriasis Treatment
Authors: Wu Dan , Shou Xin , Yu Yunru , Wang Xiaocheng , Chen Guopu , Zhao Yuanjin , Sun Lingyun
Published: September 2022

Emerging biologics, such as monoclonal antibodies (mAbs), are the most promising treatment for psoriasis, while their effective delivery to the local inflammatory area of the skin is a challenge. Here, a novel photo‐thermally dissolvable hyaluronic acid microneedle patch is presented with biologics IL‐17 mAbs and MXene encapsulation for psoriasis treatment. As the microneedles possess suitable mechanical strength and great biocompatibility, they can puncture the skin with minimal immune response. In addition, owing to the advantages of superior photothermal conversion efficiency of MXene additive, the microneedle patch can rapidly melt and release the encapsulated IL‐17 mAbs into the dermis under near‐infrared light irradiation for effective anti‐inflammatory effect around the psoriasis lesions. Based on these features, the multifunctional microneedle patch can effectively reduce psoriasis‐like skin inflammation in an imiquimod‐induced animal model, resulting in a desired therapeutic effect. Thus, the proposed microneedle delivery system provides a safer and effective strategy for psoriasis treatment, which is also valuable to improve the clinical efficacy of biologics‐based treatment for other chronic inflammatory autoimmune diseases.
Bimetallic Rechargeable Al/Zn Hybrid Aqueous Batteries Based on Al–Zn Alloys with Composite Electrolytes
Authors: Yang Xiaohu , Zhang Chen , Chai Luning , Zhang Wenming , Li Zhanyu
Published: September 2022

Aluminum is abundant and exhibits a high theoretical capacity and volumetric energy density. Additionally, the high safety of aqueous aluminum‐ion batteries makes them strong candidates for large‐scale energystorage systems. However, the frequent collapse of the cathode material and passive oxide film results in the difficult development of aqueous aluminum‐ion batteries. This work provides a novel battery system, namely, Al–Zn/Al(OTF)3+HOTF+Zn(OTF)2/AlxZnyMnO2·nH2O, with a mixed electrolyte. The cathode applies MnO topology transformation to ensure that the cathode forms AlxMnO2·nH2O. Topology transformation alters the structure of the cathode material so that Zn2+ can be intercalated into the AlxMnO2·nH2O spinel structure to provide support for the material structure. Regarding the anode, Zn2+ in the electrolyte is deposited onto Al of the anode to produce a regional Al–Zn alloy. Zn2+ is reduced to Zn metal during discharging, which adds a platform for secondary discharge beneficial for battery capacity enhancement. This system can provide a 1.6 V discharge platform, while the first cycle discharge can reach 554 mAh g‐1, thereby maintaining a high capacity of 313 mAh g‐1 after 100 cycles. This study provides a new idea for the further development of aqueous aluminum‐ion batteries (AAIBs).
Best‐Practice DFT Protocols for Basic Molecular Computational Chemistry**
Authors: Bursch Markus , Mewes Jan‐Michael , Hansen Andreas , Grimme Stefan
Published: September 2022

Nowadays, many chemical investigations are supported by routine calculations of molecular structures, reaction energies, barrier heights, and spectroscopic properties. The lion's share of these quantum‐chemical calculations applies density functional theory (DFT) evaluated in atomic‐orbital basis sets. This work provides best‐practice guidance on the numerous methodological and technical aspects of DFT calculations in three parts: Firstly, we set the stage and introduce a step‐by‐step decision tree to choose a computational protocol that models the experiment as closely as possible. Secondly, we present a recommendation matrix to guide the choice of functional and basis set depending on the task at hand. A particular focus is on achieving an optimal balance between accuracy, robustness, and efficiency through multi‐level approaches. Finally, we discuss selected representative examples to illustrate the recommended protocols and the effect of methodological choices.
The First Chiro‐Inositol Organosilicon Ferroelectric Crystal
Authors: Zhang Zhi‐Xu , Song Xian‐Jiang , Li Yi‐Rong , Chen Xiao‐Gang , Zhang Yao , Lv Hui‐Peng , Tang Yuan‐Yuan , Xiong Ren‐Gen , Zhang Han‐Yue
Published: September 2022

Organosilicons have been used extensively in aerospace, electronics, food, medicine and other fields, due to their low viscosity, hydrophobicity, corrosion resistance, non‐toxic, and physiologically inert features. Despite extensive interest, however, organosilicon ferroelectric crystals have never been found. Here, by using the chemical design strategy, we successfully obtained a molecular ferroelectric D‐chiro‐inositol‐SiMe3 with polar P43 symmetry, whose spontaneous polarization can be electrically switchable on thin film. The introduction of organosilicon groups endows the thin films with excellent softness, ductility and flexibility (extremely low hardness of 72.8 MPa and small elastic modulus of 5.04 GPa) that are desirable for biomedical and human‐compatible applications. As the first case of organosilicon ferroelectric crystal to date, this work offers a new structural paradigm for molecular ferroelectrics, and highlights their potential for flexible bio‐electronic applications.
High‐Areal Density Single‐Atoms/Metal Oxide Nanosheets: A Micro‐Gas Blasting Synthesis and Superior Catalytic Properties
Authors: Kuai Long , Liu Li , Tao Qingmei , Yu Nan , Kan Erjie , Sun Na , Liu Shoujie , Geng Baoyou
Published: September 2022

The two‐dimensional nanosheets are conducive to not only endow opened surfaces for loading active metal atoms but also boost the mass transfer for the heterogeneous reactions. The challenge is how to load and stabilize single‐atoms on nanosheets in high‐areal densities. This work reports an efficient micro‐gas blasting (MGB) strategy to access versatile noble metal single‐atoms/metal oxide nanosheets, including Ir1/CoOx, Pd1/CeO2, etc. Especially for Pt/CeO2 nanosheets (Pt1/CeO2−S), the Pt loading is increased to 15 at%. The Pt1/CeO2−S catalysts from MGB are revealed to possess superior reactivity and tolerance in the model reaction of water‐gas shift (WGS). The Pt1/CeO2−S catalyst exhibit 2–3 times reactivity that of their thicker counterpart, single‐atom Pt1/CeO2 microspheric catalyst. Moreover, the single‐atom sites in Pt1/CeO2−S (1–10 %) catalysts are stable in a harsh WGS reaction condition of 10 % CO. This work thus paves a way to access the practical single‐atom catalysts.
Tailored Cross‐β Assemblies Establish Peptide “Dominos” Structures for Anchoring Undruggable Pharmacophores
Authors: Zhang Limin , Li Mengzhen , Wang Minxuan , Li Lingyun , Guo Mingmei , Ke Yubin , Zhou Peng , Wang Weizhi
Published: September 2022

β‐sheets have the ability to hierarchically stack into assemblies, and much effort has been spent on designing different peptides to regulate their assembly behaviors. Although the progress is remarkable, it remains challenging to manipulate them in a controllable way for achieving both tailored structures and specific functions. In this study, we obtained bola‐like peptides using de novo design and combinatorial chemical screening. By regulating the solvent‐accessible surface area of the peptide chain, a series of assemblies with different tilt angles and active sites of the β‐sheet were obtained, resembling collapsed dominos. The structure‐activity relationship of the optimized peptide NQ40 system was established and its ability to target the PD‐L1 was demonstrated. This study successfully established the structure‐function relationship of β‐sheets assemblies and has positive implications on the rational design of peptide assemblies that possess recognition abilities.
Hochbelastete Lastübertragungszonen mit stumpf gestoßener Bewehrung: Experimentelle Untersuchungen und numerische Simulationen
Authors: Proksch‐Weilguni Clemens , Decker Marion , Kollegger Johann
Published: September 2022

Im modernen Tunnelbau sind der kontinuierliche Vortrieb mittels Tunnelbohrmaschine (TBM) und die Verwendung von Fertigteilsegmenten (Tübbinge) international etabliert. Bei dieser Baumethode stellt die Ausbildung der Tübbinglängsfuge, welche als trocken gestoßene Lastübertragungszone aufgefasst werden kann, aufgrund ihrer geometrischen Randbedingungen und möglichen Einbautoleranzen eine besondere Herausforderung dar. Eine Möglichkeit zur Ausbildung einer Tübbinglängsfuge bietet das von der TU Wien entwickelte Bewehrungskonzept, welches die Grundlage dieser Publikation bildet. Dabei erfolgt durch den Einsatz von stumpf gestoßenen Längsbewehrungsstäben in druckbeanspruchten Lastübertragungszonen eine Traglaststeigerung, die der Tragfähigkeit der stumpf gestoßenen Längsstäbe entspricht. Diese wird mittels experimenteller Versuche und numerischer Simulationen nachgewiesen. Experimentelle Untersuchungen und numerische Simulationen an Probekörpern mit einem Abstand zwischen den Stirnflächen und/oder einem seitlichen Versatz der gestoßenen Längsstäbe zeigten wesentlich geringere Traglaststeigerungen. Durch geeignete Maßnahmen bei der Tübbingherstellung und durch die Wahl des Stabdurchmessers der gestoßenen Längsbewehrung unter Berücksichtigung der zu erwartenden Einbautoleranzen können die Traglaststeigerungen des an der TU Wien entwickelten Bewehrungskonzepts auch in der Praxis umgesetzt werden.
Internal investigations for nonprofits: A means of identifying and addressing misconduct before the regulators come calling
Authors: Rowland Cynthia R. , Gilbert Aviva J.
Published: September 2022

Cynthia R. Rowland is chair of Farella Braun + Martel's Exempt Organizations group and Aviva J. Gilbert is co‐chair of the firm's White Collar Criminal Defense & Internal Corporate Investigations practice. In this article, they discuss strategies for handling internal misconduct allegations at nonprofit organizations.
Nitrothiazole‐Thiazolidinone Hybrids: Synthesis and in Vitro Antimicrobial Evaluation
Authors: Hart Dylan , Legoabe Lesetja J. , Jesumoroti Omobolanle J. , Jordaan Audrey , Warner Digby F. , Steventon Rebecca , Beteck Richard M.
Published: September 2022

Herein we report the synthesis of novel compounds inspired by the antimicrobial activities of nitroazole and thiazolidin‐4‐one based compounds reported in the literature. Target compounds were investigated in vitro for antitubercular, antibacterial, antifungal, and overt cell toxicity properties. All compounds exhibited potent antitubercular activity. Most compounds exhibited low micromolar activity against S. aureus and C. albicans with no overt cell toxicity against HEK‐293 cells nor haemolysis against human red blood cells. Notably, compound 3b exhibited low to sub‐micromolar activities against Mtb, MRSA, and C. albicans. 3b showed superior activity (0.25 μg/ml) against MRSA compared to vancomycin (1 μg/ml).
Ordered PtCo Intermetallics Featuring Nitrogen‐Doped Carbon Prepared by Surface Coating Strategy for Oxygen Reduction Reaction
Authors: Chen Meida , Zhou Shangyan , Liao Wei , Wang Zhengcheng , Long Jin , Zhou Qian , Wang Qingmei
Published: September 2022

Improving the activity and stability of Pt‐based electrocatalysts is essential for large‐scale commercial applications of fuel cells. The ordered Pt‐based alloy nanomaterials encapsulated by coating have attracted significant attention. Here, we displayed a surface coating strategy to synthesize structurally ordered PtCo alloy catalysts featuring nitrogen‐doped carbon (NC). Experimental results reveal that the sample with appropriate dopamine feeding content shows enhanced oxygen reduction activity and stability, which exhibits a mass activity of 1.36 mA ⋅ mg−1Pt and specific activity of 1.98 mA ⋅ cm−2, superior to those of excessive or low dopamine adding content samples and commercial Pt/C catalyst. The enhanced electrocatalytic performance of this catalyst was attributed to the combined effect including the protection of suitable thickness NC shells, strong electronic interaction and high ordering degree. In this work, the surface coating strategy provides available references to further improve the oxygen reduction performance of PtM alloy catalysts.
Investigations on the Shear Capacity of Stainless Steel for its Use in Steel and Composite Bridge Construction
Authors: Ungermann Dieter , Schweyher Janik
Published: September 2022

The paper deals with the shear capacity and the shear buckling behaviour of plates made of (lean) duplex stainless steel. For this purpose, twelve experimental tests on torsionally loaded square box girders were carried out to investigate the shear capacity. Two different materials and three different buckling slendernesses were investigated. An FE model was created and calibrated using the experimental results. Subsequently, a parameter study was carried out in order to be able to cover a larger buckling slenderness range. The experimental and numerical results were then compared with the specifications of EN 1993‐1‐4 and an assessment of the specifications is provided.
Bending Behavior of Deformed Steel Bridge Girder
Authors: Yamaguchi Eiki , Nakashima Daisuke , Amamoto Takuya
Published: September 2022

The first author was asked to evaluate the safety of a steel bridge on the municipal road with which the load of a truck running on the expressway underneath appeared to have collided. The bridge consists of two main girders and the orthotropic deck, and one of the main girders was found severely damaged. The damage includes the out‐of‐plane displacement of the lower part of the web, the bend/buckling of the transvers stiffeners and the separation of the transvers stiffeners from the web, the fracture of the bolted connections between the transvers stiffeners and the lateral struts. In the investigation, the deformation of the main girder due to collision is reproduced by the finite element analysis first. The result is quite satisfactory with the residual displacement in good agreement with that measured in situ. The steel girder deformed by the collision is then loaded to see its bending behavior. The result indicates that the initial stiffness is reduced by 14% and the reduction in the bending strength is 0.8%. The bending behavior is further investigated by removing the transverse stiffeners, since many of the transverse stiffeners were damaged rather badly. The results indicate that the contribution of the transverse stiffeners to the bending behavior is very little and that the damages of the transverse stiffeners is not a problem at all. Hence it may be concluded that the damaged girder due to collision doesn't threaten the safety of the bridge.
CFS Columns Under Buckling Interaction: Direct Strength Method Generalised Approach
Authors: Matsubara Gustavo Yoshio , de Miranda Batista Eduardo
Published: September 2022

Cold‐Formed Steel (CFS) members are highly susceptible to several structural instability phenomena, involving either individual (Local – L, Distortional – D and Global – G) or interaction (LD, LG, DG, and LDG) buckling modes. The buckling mode interaction of CFS columns and beams may lead to strength erosion compared to isolated modes and must be considered in structural design. The North American, Australian/New Zealand and Brazilian standards incorporated the Direct Strength Method (DSM) that provides accurate design approach for columns and beams affected by L, D, G, and LG buckling modes. Moreover, the coupled LD, DG, and LDG buckling modes are not currently considered in the DSM and many research projects have been focused on these topics. The procedure adopted by DSM estimates the CFS member strength through experimentally calibrated design strength curves, considering the relationship between the member elastic stability and the steel yielding property. In this context, the present paper presents the main results of the investigation, based on both experimental and finite element method numerical results, that conducted to calibrated Winter‐type strength curves for CFS columns covering LD, DG, and LDG buckling modes. To take into account the effect of the buckling modes interaction, the proposed procedure for design purposes incorporates the slenderness factors ratio RλDL = λD/λL and λG/ λmaxLD, with λmaxLD = max {λL, λD} and λL, λD, λG as the local, distortional and global slenderness factors, respectively.
A New Eurocode‐compliant Design Approach for Cold‐Formed Steel Sections
Authors: Ungermann Dieter , Lemański Tim , Brune Bettina
Published: September 2022

A new, Eurocode‐compliant design approach based on the Direct Strength Method (DSM) combined with EN 1993‐1‐3 was developed for the design of thin‐walled cold‐formed steel sections. The new design approach transfers cross‐sectional resistance according to DSM, based on numerical elastic buckling analyses on the gross cross‐section, into the global stability check according to EN 1993‐1‐3. Experimental investigations on various perforated and unperforated cold‐formed sections in compression and bending serve to verify the new design approach. In addition, a numerical model was developed, it was calibrated on the test results and used for further parametric analyses on the load‐carrying capacity of cold‐formed sections.
Energy‐based Equations for Local and Anti‐symmetric Distortional Modes of Lipped Channel Columns
Authors: de Salles Guilherme , Taissum Daniel , Batista Eduardo
Published: September 2022

This paper presents an energy‐based approach to obtain the critical length and stress of local (L) and anti‐symmetric distortional (D2) modes of simply supported lipped channel columns. For each mode, deformed shapes are assumed and the Rayleigh Quotient Method is applied to obtain analytical expressions for the buckling stress. The shape functions adopted for local buckling ensure compatibility of rotation and bending moments at wall junctions and at the stiffener's free end. For the D2 mode, equilibrium of bending and twisting moments are considered leading to an analytical derivation of the mode's warping stress distribution. While for L mode it is not feasible to obtain a closed expression for the critical length (but a simple length testing procedure is sufficient), for D2 mode an expression dependent on geometrical properties is derived. The developed equations for L and D2 modes are validated against CUFSM's pure local modes and GBTul's pure D2 mode (mode 6 in GBTul convention) respectively. For sections with flange‐to‐web width ratio, bf/bw, ranging from 0.2 to 1.0 and lip‐to‐web width ratio, bs/bw, from 0.1 to 0.4 the average ratios obtained for critical stresses (σcr,reference/σcr,proposed) are 1.014±0.019 and 1.011 ± 0.014 for L and D2 modes respectively.
New Test Bed for Corroded Large Size Bolted Connections Under Fatigue and Pretension
Authors: Betz Kai Stephan , Schaumann Peter , Kulikowski Jan
Published: September 2022

In this paper, a newly developed test method to evaluate the influence of corrosion on pretension and fatigue of bolted connections is presented, suitable from size M36 to M72. A first preliminary series of M30 property class 10.9 bolts were tested to validate the individual test setup steps and to detect challenges and improvement. Pretension load tests, static load tests and fatigue load tests were performed while monitoring stresses on a small number of bolts. The method presented is used to compare different coatings for bolts, like Hot‐dip galvanized coatings and zinc flake coatings, as well as nano‐coatings. To create a realistic approach on offshore corrosion and loading conditions, the bolts will be preloaded in a clamping device resembling the ring flange of an offshore wind tower segment. In a next step, the bolts are corroded in a climate chamber, using the salt spray test or condensation test. Following the corrosion process, the bolts are tested for fatigue without loosening the nut and damaging the thread. Before corrosion and after the fatigue test, 3D surface scans are made to document the corrosion process and to create numerical models of the corroded surface. The method presented offers a new way to evaluate fatigue, pretension and corrosion effects, which is validated on bolts M30 property class 10.9. In close future, the test method is used for larger series of corroded M36 property class 10.9 bolts, having different coating systems applied.
Strengthening of Steel Beam by Inclined Stiffeners
Authors: Vild Martin , Bajer Miroslav , Barnat Jan , Holomek Josef
Published: September 2022

There are several ways how to increase the bending resistance of a beam. The simplest method is to increase the cross‐section size. But this method may not be the most efficient or feasible, especially in the case of an existing building in need of strengthening. In this paper, the method of strengthening a beam by welded inclined stiffeners is investigated. The beam is susceptible to lateral‐torsional buckling. A sensitivity study is prepared for the beam length and cross‐section size, boundary conditions, and the number and position of stiffeners. A validated numerical model using Component‐based Finite Element Method is used. The model combines shell elements for analyzed member and bar elements for related members. The joints are included in the model. Bolts and welds are simulated by special nonlinear elements with resistance based on codes. Validation and verification of the model is presented. It is based on the experiment performed at AdMaS center at Brno University of Technology of a beam with semi‐rigid joints loaded by three‐point bending. The model is verified by comparing critical buckling load and buckling resistances of columns and beams with clear boundary conditions. The results are also compared to those by another general finite element software, ANSYS and ABAQUS.
Numerical Investigation of Doubler Plate Reinforced Tubular T‐joints under Chord Compression Loads
Authors: Pamplona Gil , Vellasco Pedro , Tenchini André , Lima Luciano , Rodrigues Monique
Published: September 2022

Tubular profiles present geometric properties that enable a better structural behaviour in comparison with other cross‐sections when subjected to torsion. In regards to the joints between its elements, there are a few parameters that govern the design of the T‐joint resistance and change its failure mode. This paper presents a numerical investigation of square hollow sections (SHS) T‐joints with doubler plate reinforcement on the upper chord face under axial compression. The geometrical parameters are the slenderness chord, brace to chord width ratio, and reinforcement plate thickness combined with a certain level of axial compression on the chord. A numerical model has been developed compared with experimental tests. In addition, a parametric study was performed based in order to evaluate the parameters that influence the structural behaviour of reinforced T‐joint. Concerning outcomes, the increase of reinforcement plate thickness was responsible for the improvement of the joint capacity. In opposite to recommended by actual codes, the compression applied on the chord reduced the joint resistance mainly for those slender chord wall. Comparing with formulation from both code and other works, it was possible to conclude that there is an unsafe level from the actual codes.
Imperfections for the LTB‐design of Members with I‐sections
Authors: Stroetmann Richard , Fominow Sergei
Published: September 2022

For the stability assessment of members and structures according to EN 1993‐1‐1 the equivalent member method, the geometrical nonlinear calculation with equivalent geometrical imperfections or the GMNIA analysis with geometrical imperfections and residual stresses can be used alternatively. The second possibility requires a corresponding model for the cross‐section resistance. For the verification of lateral torsional buckling, bow imperfections e0 out of plane are defined, which lead in combination with the given loading in plane and the geometrical non‐linear analysis to bending Mz and torsion of the members. The amplitudes of the imperfections are highly dependent on the nature of the approach (e.g., scaling of the buckling shape, assumption of bow imperfections) and the resistance model for the members. Within the framework of the scientific work supervised by the TU Dresden and the TU Darmstadt [1], extensive parameter studies were carried out to calibrate imperfections for lateral torsional buckling based on the GMNIA. After determining the nature of imperfections and the design models for section resistance, this paper presents results of these parameter studies and shows the calibration of imperfections for a standardisation proposal based on EN1993‐1‐1. The evaluation of the data in combination with the necessary simplifications for the design practice leads to appropriate definitions of imperfection values e0,LT and the necessary differentiations.