Electrical Capacitance Volume Tomography (ECVT) for Characterization of Additively Manufactured Lattice Structures (AMLS) in Gas-Liquid Systems

Against the background of current and future global challenges, such as climate change, process engineering requires increasingly specific solutions adapted to the respective problem or application, especially in gas–liquid contact apparatuses. One possibility to adjust the conditions in this kind of apparatuses is an intelligent and customized structuring, which leads to consistent fluid properties and flow characteristics within the reactor. In the course of this, the interfacial area for mass transfer, as well as residence times, have to be adjusted and optimized specifically for the respective application. In order to better understand and advance the research on intelligent customized additively manufactured lattice structures (AMLS), the phase distributions and local gas holdups that are essential for mass transfer are investigated for different structures and flow conditions. For the first time a tomographic measurement technique is used, the Electrical Capacitance Volume Tomography (ECVT), and validated with the volume expansion method and a fiber optical needle probe (A2PS-B-POP) for an air-water system for different modes of operation (with or without co-current liquid flow in empty or packed state). The ECVT proved to be particularly useful for both in the empty tube and the packed state and provided new insights into the phase distributions occurring within structured packings, which would have led to significantly underestimated results based on the visual reference measurements, especially for a densely packed additively manufactured lattice structure (5 mm cubic on the tip). Particularly for the modified structures, which were supposed to show local targeted differences, the ECVT was able to resolve the changes locally. The additional use of a pump for co-current flow operation resulted in slightly higher fluctuations within the ECVT data, although local events could still be resolved sufficiently. The final comparison of the empty tube at rest data with a fiber optical needle probe showed that the results were in good agreement and that the local deviations were due to general differences in the respective measurement techniques.

Compressive Behaviour of Aluminium Pyramidal Lattice Material-Filled Tubes

This study focuses on the uniaxial compressive behaviour of thin-walled Al alloy tubes filled with pyramidal lattice material. The mechanical properties of an empty tube, Al pyramidal lattice material, and pyramidal lattice material-filled tube were investigated. The results show that the pyramidal lattice material-filled tubes are stronger and provide greater energy absorption on account of the interaction between the pyramidal lattice material and the surrounding tube.

Reviving Matrix for Nerve Reconstruction in Rabbit Model of Chronic Peripheral Nerve Injury With Massive Loss Defect

Background and Aims: The aim of this study was to investigate the innovative guiding regenerative gel (GRG) and antigliotic GRG (AGRG) fillings for nerve conduits, prepared with Food and Drug Administration (FDA)-approved agents and expected to provide an alternative to autologous nerve graft and to enable reconnection of massive nerve gaps in a rabbit model of chronic peripheral nerve injury with massive loss defect that simulates the human condition of chronic injury with a large gap.Methods: The components and dosimetry for GRG and AGRG formulations were investigated in vitro on nerve cell culture and in vivo on 10-mm reconstructed sciatic nerves of 72 rats using different concentrations of agents and completed on a rabbit model of delayed (chronic) complete peripheral nerve injury with a 25-mm gap. Forty rabbits underwent delayed (9 weeks after complete injury of the tibial portion of the sciatic nerve) nerve tube reconstruction of a gap that is 25 mm long. GRG and AGRG groups were compared with autologous and empty tube reconstructed groups. Rats and rabbits underwent electrophysiological and histochemical assessments (19 weeks for rats and 40 weeks for rabbits).Results: Application of AGRG showed a significant increase of about 78% in neurite length per cell and was shown to have the most promising effect on neuronal outgrowth, with total number of neurites increasing by 4-fold. The electrophysiological follow-up showed that AGRG treatment is most promising for the reconstruction of the tibial portion of the sciatic nerve with a critical gap of 25 mm. The beneficial effect of AGRG was found when compared with the autologous nerve graft reconstruction. Thirty-one weeks post the second surgery (delayed reconstruction), histochemical observation showed significant regeneration after using AGRG neurogel, compared with the empty tube, and succeeded in significantly regenerating the nerve, as well as the autologous nerve graft, which was almost similar to a healthy nerve.Conclusion: We demonstrate that in the model of delayed peripheral nerve repair with massive loss defect, the application of AGRG led to a stronger nerve recovery and can be an alternative to autologous nerve graft.

Improvement of a Nusselt-Based Simulation Model for Heat Transfer in Rotary Heat Exchangers

In the last 50 years, the technology of rotary heat exchangers has not changed considerably. A reliable simulation can help improve the design of this technology. In this work, a simulation for rotary heat exchangers was developed and validated with multiple experimental data. This simulation takes an innovative approach based on locally calculated heat transfer coefficients and considers the entry region effect. This approach proved to be accurate since the average difference between the experimental results and the proposed model with a constant heat boundary condition is 0.1% and the maximum absolute deviation 1%. Experimental, as well as simulation results, indicate that lower empty tube gas velocity (1 m/s) and higher rotational speed (12 rpm) improve thermal efficiency compared to commonly used operating conditions. Additionally, a new model for predicting the local internal Nusselt number for sine ducts in the rotor channels is proposed, which considers the entry region effect.

Fenomena Calon Tunggal dalam Pesta Demokrasi

Concurrent local elections to be held in December 2015, characterized by the dynamics of democracy and new political dynamics. Dynamics it is the birth of a single candidate in several areas that will carry out the election. It is on the one hand shows that the dynamics of democracy in the country increasingly show progress and our society is increasingly “literacy” and political savvy, but on the other hand it raises a new problem, namely whether the elections will be postponed or published decree. This happens because the legislators did not expect the birth of a single candidate. This fact shows that the lawmakers have not been able to make laws that meet the philosophical and sociological aspects of that legislation was well received presence in the midst of society without conflict and live longer. Because it is common to occur in Indonesia legislation only whole corn.Issues to be addressed in this study is what legal remedies in the face of a single candidate and how the legal steps to prevent the birth of a single candidate in the elections. This study is a normative legal research, using qualitative juridical analysis. The result showed that the legal solutions that can be done to deal with a single candidate is to 1). Exposes a single candidate with an empty tube, 2). Delay the election until the election outright in 2017. 3). Published the decree. While the legal steps that can be taken to prevent the birth of a single candidate is 1. Revise election laws, by adding specific chapter or article concerning a single candidate, 2. Increasing political education for the public and political party cadres and prepare the mature cadre in the party’s internal.

Lemon-shaped halo archaeal virus His1 with uniform tail but variable capsid structure

Lemon-shaped viruses are common in nature but so far have been observed to infect only archaea. Due to their unusual shape, the structures of these viruses are challenging to study and therefore poorly characterized. Here, we have studied haloarchaeal virus His1 using cryo-electron tomography as well as biochemical dissociation. The virions have different sizes, but prove to be extremely stable under various biochemical treatments. Subtomogram averaging of the computationally extracted virions resolved a tail-like structure with a central tail hub density and six tail spikes. Inside the tail there are two cavities and a plug density that separates the tail hub from the interior genome. His1 most likely uses the tail spikes to anchor to host cells and the tail hub to eject the genome, analogous to classic tailed bacteriophages. Upon biochemical treatment that releases the genome, the lemon-shaped virion transforms into an empty tube. Such a dramatic transformation demonstrates that the capsid proteins are capable of undergoing substantial quaternary structural changes, which may occur at different stages of the virus life cycle.

Crushing Behaviour of Empty Steel Tubes under Eccentric Loading

This present paper describes numerically the tube responses subjected to eccentric loading using ANSYS finite element program. According to literature review, tremendous amount of works available on discussing the axial crushing of empty tube under axial loading. However, lack of work related with the crashworthiness aspect of tube crushing under eccentric loading was identified. Therefore, the eccentric compressive loading on the empty tubes were focused. There have important parameters were studied such as the eccentric loading. According to the present result, the behaviour of crashworthiness expected to increase when the increment of eccentric loading was introduced. The crashworthiness behaviour and energy absorption capabilities demonstrated efficiently by the collected data mean crushing force and peak crashing force.

Crushing Behaviour of Empty Steel Tubes under Oblique Loading

<span><p><span lang="EN-GB">This paper presents numerically the empty tube response subjected to oblique loading. According to literature survey, there have large number of works discuss on the crushing performance when subjected to axial loading. However, lack of work available on the crushing behaviour under oblique loading.</span><span lang="EN-GB"> </span><span lang="EN-GB">Therefore, this work presents the numerical studies on the crushing behavior of empty tube subjected to oblique loading. ANSYS Finite element program was used to model and solve the problem. The developed model was firstly validated with the previous result and it is found that the results obtained were acceptable. There were two important parameters were used such as tube geometry and oblique loading. According to the present results, when oblique angles were increased, the crushing performance decreased. However, when the elliptical ratios were increased, the energy capabilities increased. </span></p>

An Experimental and Numerical Analysis of Empty and Foam-Filled Aluminium Conical Tubes under Oblique Impact Loading

This paper presents the crushing behaviour of empty and foam-filled conical aluminium alloy (AA6061-T6) tubes under oblique impact loading using a validated nonlinear finite element (FE) code, LS-DYNA. The study aims to assess the beneficial of foam filling on the energy absorption in terms of mass reduction, for variations in filler density and geometrical parameters of AA6061-T6 tubes. The results obtained successfully identified the critical tube mass and critical foam density. It is evident that foam filling successfully induced high Specific Energy Absorption (SEA) value of foam-filled tubes thus proving that the assessment of critical total tube mass and critical foam density point is vital in identifying proper combination of tube-filler to the effectiveness of foam-filled tubes. The combination of AA6061-T6 tube and aluminium foam demonstrates pronounced SEA increase as high as 72.3% compared to the empty tube.

An Experimental Study of Square Aluminium Tubes with Honeycomb Core Subjected to Quasi-Static Compressive Loads

Thin-walled honeycombs have been extensively investigated and they are often used as sandwich panels to enhance the energy absorption in many applications including vehicles. In this study, axial compressive tests at three different velocities (3, 30 and 300 mm/min, respectively) by using an MTS machine were conducted with both empty and hybrid aluminium tubes filled with aluminium honeycomb. The aim of this work is to study the contribution of aluminium honeycomb in square hybrid tubes in terms of the deformation mode and energy absorption. Square aluminium tubes made of AA 6060-T5 with two different side lengths, 40 and 50 mm, were used. Two types of honeycombs made of AA 5052 with different cell wall thicknesses were used in this study. The force and displacement of the tubes were recorded during the test. The specific energy absorption (SEA) of honeycomb-filled tubes was compared with the sum of the SEA of an empty tube and honeycomb. It was noticed that the SEA of the hybrid tubes depended on the honeycomb density and the loading velocity within the velocity range studied.