Stress and strain state of concrete during freezing and thawing cycles

The objective of this work is to calculate the pressures, stresses, and strains induced into moist concrete during freezing and thawing. The applied theory is based on thermodynamics and the linear theory of elasticity. If no additional salts are dissolved in the pore water the inputs needed in the theory are relative humidity and temperature measured in the sample chamber and inside concrete and evaporable water amount in the pore structure. Theoretical results were compared with the test results made with two concretes cured under water or at 96% relative humidity. One of the concretes was air entrained and in the comparison concrete no air-entraining agents were used. In the test cylinders cured under water the largest tensional stresses in freezing occurred on the surface of the test cylinders both in the axial and tangential direction. The largest tensional stress was 2.2 MPa, both in air-entrained and in non air-entrained concretes. The largest tensional stresses in the warming phase took place at the end of the thawing period when the chamber temperature was around +5 °C. Then the maximum tension occurred in the middle of the concrete cylinder in the axial direction of the cylinder. This maximum tensional stress was over 2.5 MPa in the air-entrained concrete cured in the relative humidity of 96%. The thermodynamic pumping effect at the end of the thawing phase in every cycle can increase the pore water amount remarkably if free water or moisture is available on the surface of the structure or in the environment vapor. The thermodynamic pumping effect seems to be remarkably greater and more dangerous in air-entrained concretes.     

Validation of the Climate-SAF surface broadband albedo product: Comparisons with in situ observations over Greenland and the ice-covered Arctic Ocean

This paper describes a validation study performed by comparing the Climate-SAF Surface Albedo Product (SAL) to ground truth observations over Greenland and the ice-covered Arctic Ocean. We compare Advanced Very High Resolution Radiometer (AVHRR)-based albedo retrievals to data from the Greenland Climate Network (GCN) weather stations and the floating ice station Tara for polar summer 2007. The AVHRR dataset consists of 2755 overpasses. The overpasses are matched to in situ observations spatially and temporally. The SAL algorithm presented here derives the surface broadband albedo from AVHRR channels 1 and 2 using an atmospheric correction, temporal sampling of an empirical Bidirectional Reflectance Distribution Function (BRDF), and a narrow-to-broadband conversion algorithm. The satellite product contains algorithms for snow, sea ice, vegetation, bare soil, and water albedo. At the Summit and DYE-2 stations on the Greenland ice sheet, instantaneous SAL RMSE is 0.073. The heterogeneous surface conditions at satellite pixel scale over the stations near the Greenland west coast increase RMSE to > 0.12. Over Tara, the instantaneous SAL RMSE is 0.069. The BRDF sampling approach reduces RMSE over the ice sheet to 0.053, and to 0.045 over Tara. Taking into account various sources of uncertainty for both satellite retrievals and in situ observations, we conclude that SAL agrees with in situ observations within their limits of accuracy and spatial representativeness.     

Overlap-freeness in infinite partial words

We prove that there exist infinitely many infinite overlap-free binary partial words containing at least one hole. Moreover, we show that these words cannot contain more than one hole and the only hole must occur either in the first or in the second position. We define that a partial word is $k$-overlap-free if it does not contain a factor of the form $xyxyx$ where the length of $x$ is at least $k$. We prove that there exist infinitely many 2-overlap-free binary partial words containing an infinite number of holes.     

Extension of the decidability of the marked PCP to instances with unique blocks

In the Post Correspondence Problem (PCP) an instance (h,g)$(h,g)$ consists of two morphisms h$h$ and g$g$, and the problem is to determine whether or not there exists a nonempty word w$w$ such that h(w)=g(w)$h\left(w\right)=g\left(w\right)$. Here we prove that the PCP is decidable for instances with unique blocks using the decidability of the marked PCP. Also, we show that it is decidable whether an instance satisfying the uniqueness condition for continuations has an infinite solution. These results establish a new and larger class of decidable instances of the PCP, including the class of marked instances.     

Therapeutic Efficacy and Outcomes of Remdesivir versus Remdesivir with Tocilizumab in Severe SARS-CoV-2 Infection

The infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) generated many challenges to find an effective drug combination for hospitalized patients with severe forms of coronavirus disease 2019 (COVID-19) pneumonia. We conducted a retrospective cohort study, including 182 patients with severe COVID-19 pneumonia hospitalized between March and October 2021 in a Pneumology Hospital from Cluj-Napoca, Romania. Among patients treated with standard of care, 100 patients received remdesivir (R group) and 82 patients received the combination of remdesivir plus tocilizumab (RT group). We compared the clinical outcomes, the inflammatory markers, superinfections, oxygen requirement, intensive care unit (ICU) admission and mortality rate before drug administration and 7 days after in R group and RT group. Borg score and oxygen support showed an improvement in the R group (p < 0.005). Neutrophiles, C-reactive protein (CRP) and serum ferritin levels decreased significantly in RT group but with a higher rate of superinfection in this group. ICU admission and death did not differ significantly between groups. The combination of remdesivir plus tocilizumab led to a significantly improvement in the inflammatory markers and a decrease in the oxygen requirement. Although the superinfection rate was higher in RT group than in R group, no significant difference was found in the ICU admission and mortality rate between the groups.     

BOAR: an advanced HW/SW coemulation environment for DSP system development

The BOAR emulation system is targeted to hardware/software (HW/SW) codevelopment of advanced embedded DSP and telecom systems. The challenge of the BOAR system is efficient customization of programmable hardware, and dedicated partitioning routine to target applications and structures, which allows quite high overall system performance. The system allows multiple configurations for communication between processors and field programmable gate arrays (FPGAs) making the BOAR system an efficient tool for real-time HW/SW coverification. The reprogrammable hardware of the emulation tool is based on four Xilinx 4000-series devices, two Texas TMS320C50 signal processors and one Motorola MC68302 microcontroller. With current devices the BOAR hardware provides approximately 40–70 kgates of logic capacity in DSP applications. The emulation capacity can be expanded by connecting several similar boards in chain. The system has also a versatile internal reprogrammable test environment for test bench development, performance evaluations and design debugging. The logic development environment is based on the Synopsys synthesis tools and an automatic design management software, which performs resource mapping and performance-driven design partitioning between FPGAs. The emulation hardware is currently connected to logic and software development environments via an RS-232C bus. The BOAR emulation system has been found a very efficient platform for real-life prototyping of different types of DSP algorithms and systems, and validating correct functionality of a VHDL macro library.     

Identification and Ruminal Outflow of Long-Chain Fatty Acid Biohydrogenation Intermediates in Cows Fed Diets Containing Fish Oil

The abundance of 20- to 24-carbon fatty acids in omasal digesta of cows fed grass silage-based diets supplemented with 0 (Control) and 250 g/day of fish oil (FO) was examined to investigate the fate of long-chain unsaturated fatty acids in the rumen. Complimentary argentation thin-layer chromatography and gas-chromatography mass-spectrometry analysis of fatty acid methyl esters and corresponding 4,4-dimethyloxazoline derivatives prepared from fish oil and omasal digesta enabled the structure of novel 20- to 22-carbon fatty acids to be elucidated. Compared with the Control, the FO treatment resulted in the formation and accumulation of 27 novel 20- and 22-carbon biohydrogenation intermediates containing at least one trans double bond and the appearance of cis-14 20:1, 20:2n-3, 21:4n-3 and 22:3n-6 not contained in fish oil. No conjugated ≥20-carbon fatty acids were detected in Control or FO digesta. In conclusion, fish oil in the diet results in the formation of numerous long-chain biohydrogenation intermediates in the rumen of lactating cows. Comparison of the intake and flow of 20-, 21- and 22-carbon fatty acids at the omasum in cows fed the Control and FO treatments suggests that the first committed steps of 20:5n-3, 21:5n-3 and 22:6n-3 hydrogenation in the rumen involve the reduction and/or isomerisation of double bonds closest to the carboxyl group.     

Reaction engineering studies in a polytropic fixed-bed reactor over a highly active and selective catalyst for oxidative methane coupling

The oxidative coupling of methane (OCM) was carried out in a polytropic fixed-bed reactor applying a Zr/La/Sr catalyst developed by the Neste company. Over this catalyst the OCM reaction follows a complex reaction scheme which includes primary parallel reaction steps to CO, CO₂ and C₂H₆ and consecutive reactions of ethane to ethylene or CO_x. Yield of higher hydrocarbons C₂₊ obtained with this catalyst strongly depended on reaction conditions, i.e. low partial pressures of methane and oxygen obtained by diluting the feed gas with nitrogen and high reaction temperatures promoted C₂₊ selectivity and yield. The maximum yield amounted to 21.4% (20 Vol.-% CH₄, 9 Vol.-% O₂, 71 Vol.-% N₂, T = 860°C; X_CH4 = 41.8%, S = 52.5%). This result belongs to the highest yields reported in the open literature.     

The Strategic Incrementalism of Lahti Master Planning: Three Lessons

ABSTRACT

The city of Lahti, Finland, has developed a unique policy of combining city strategy work with strategic master planning in an iterative process. It thereby offers insights to research on strategic spatial planning, exemplifying how institutional frameworks of statutory planning can be utilized as resources in strategic planning. Three lessons from the Lahti case are drawn: (1) utilize the moments of opportunity in the institutional environment of statutory planning, (2) shift the focus from the level of ‘strategic plans’ to the policy level of strategy work, (3) develop strategic planning as a platform for diverse ‘languages’.     

Microfluidics-Based Force Spectroscopy Enables High-Throughput Force Experiments with Sub-Nanometer Resolution and Sub-Piconewton Sensitivity

Several techniques have been established to quantify the mechanicals of single molecules. However, most of them show only limited capabilities of parallelizing the measurement by performing many individual measurements simultaneously. Herein, a microfluidics-based single-molecule force spectroscopy method, which achieves sub-nanometer spatial resolution and sub-piconewton sensitivity and is capable of simultaneously quantifying hundreds of single-molecule targets in parallel, is presented. It relies on a combination of total internal reflection microscopy and microfluidics, in which monodisperse fluorescent beads are immobilized on the bottom of a microfluidic channel by macromolecular linkers. Application of a flow generates a well-defined shear force acting on the beads, whereas the nanomechanical linker response is quantified based on the force-induced displacement of individual beads. To handle the high amount of data generated, a cluster analysis which is capable of a semi-automatic identification of measurement artifacts and molecular populations is implemented. The method is validated by probing the mechanical response polyethylene glycol linkers and binding strength of biotin–NeutrAvidin complexes. Two energy barriers (at 3 and 5.7 Å, respectively) in the biotin–NeutrAvidin interaction are resolved and the unfolding behavior of talin's rod domain R3 in the force range between 1 to ≈10 pN is probed.