THE INFLUENCE OF SINGLY CHARGED IONS ON THE TRANSLATIONAL MOTION OF MOLECULES IN EXTREMELY DILUTE AMIDE SOLUTIONS

The type of short range solvation of Li+, Na+ K+, Rb+, Cs+, NH4+, Cl– , Br–, I–, ClO4– ions has been determined and analyzed in formamide (FA), N-methylformamide (MFA), N-dimethylformamide (DMF) at 298.15 K. In order to determine the type of ion solvation we used familiar-variable quantitative parameter (– ri), where is the translational displacement length of ion, ri is its structural radius. It was found that the difference (– ri) is equal to the coefficient of attraction friction (CAF) of ions normalized to the solvent viscosity and hydrodynamic coefficient. The sign of the CAF is determined by the sign of the algebraic sum of its ion-molecular and intermolecular components. In amide solutions the studied cations are cosmotropes (positively solvated ((– ri) > 0), structure-making ions) and anions are chaotropes (negatively solvated ((– ri) < 0 ), structure-breaking ions). In the amide series, regardless of the sign (– ri), the near-solvation enhances, which can be explained by the weakening of the specific interaction between the solvent molecules. The decrease of and respectively (– ri) with increasing cation radius in a given solvent is the result of weakening of its coordinating force due to the decrease of charge density in the series Li+–Na+–K+–Rb+–Cs+. The increase of (and (– ri), correspondingly) for the ions studied in the series FA- MFA-DMF can be explained by the weakening of intermolecular interactions in this series, which leads to the strengthening of solvation. It was found that for the halide ions in the series FA-MFA-DMF the regular growth of parameter is explained by the weakening of the solvent structure. It was shown that Li+ ion with the lowest diffusion coefficient among cations and the highest value forms kinetically stable complexes in amide solutions.

Mechanically transduced immunosorbent assay to measure protein-protein interactions

Measuring protein-protein interaction (PPI) affinities is fundamental to biochemistry. Yet, conventional methods rely upon the law of mass action and cannot measure many PPIs due to a scarcity of reagents and limitations in the measurable affinity ranges. Here, we present a novel technique that leverages the fundamental concept of friction to produce a mechanical signal that correlates to binding potential. The mechanically transduced immunosorbent (METRIS) assay utilizes rolling magnetic probes to measure PPI interaction affinities. METRIS measures the translational displacement of protein-coated particles on a protein-functionalized substrate. The translational displacement scales with the effective friction induced by a PPI, thus producing a mechanical signal when a binding event occurs. The METRIS assay uses as little as 20 pmols of reagents to measure a wide range of affinities while exhibiting a high resolution and sensitivity. We use METRIS to measure several PPIs that were previously inaccessible using traditional methods, providing new insights into epigenetic recognition.

ANALISIS UNJUK KERJA RANCANGAN STEAM CONDENSATION TANK BERBASIS SIMULASI SOFTWARE

Steam condensation tank merupakan salah satu komponen pada fasilitas Passive Helical Coil Condensation System (PaHCCS) pada PASCONEL yang berfungsi sebagai kondensor uap bertekanan. Steam condensation tank didesain menggunakan tube stainless steel 304 (SS 304) dengan diameter luar 600 mm dan ketebalan 9,53 mm serta ketinggian total 2970,8 mm. Steam condensation tank dioperasikan pada tekanan 20 bar, temperatur diatas 100°C dan dilengkapi dengan helical coil tube sebagai pengambil kalor pada uap bertekanan. Simulasi unjuk kerja rancangan steam condensation tank ini bertujuan untuk mengetahui keselamatan dan keamanan saat dioperasikan. Analisis unjuk kerja dilakukan menggunakan software CATIA, dimana pemodelan 3-dimensi rancangan steam condensation tank dioperasikan secara simulasi dengan 1,5 kali dari tekanan dan temperatur operasional. Hasil analisis kekuatan mekanik mendapatkan tegangan mekanik terbesar sebesar 9,57 x 107 N/m2 pada bagian tengah shell rancangan steam condensor tank. Tegangan mekanik tersebut tidak berdampak pada rancangan steam condensor tank berbahan SS 304 karena besar tegangan mekanik yang terjadi lebih kecil daripada yield strength material SS 304 yaitu sebesar 1,73 x 108 N/m2 dan masih berada didaerah elastisnya . Translational displacement maksimal yang terjadi pada rancangan steam condensor tank sebesar 6,2 mm adalah sangat kecil dan 1/500 dari ukuran total panjang rancangan steam condensor tank. Dengan demikian rancangan steam condensor tank aman untuk digunakan sebagai sarana penelitian.Kata kunci: Steam Condensation Tank, PASCONEL, tegangan mekanik, translational displacement

ANALISIS PENGARUH PEMODELAN SAMBUNGAN TITIK BUHUL PADA STRUKTUR KUBAH GEODESIK

The geodesic dome consists of steel rod elements joined together to form a single structure. Generally, these geodesic domes are analyzed by assuming the joints of the gusset points are joints and only receive axial forces on the rods. However, in reality, it is not easy to apply gusset joints as pure joints in construction. This research will analyze the geodesic dome by modeling the joints of the gusset points as joints where there is only axial force arising on the rods and modeling the rigid gusset points where there will also be moments and shear on the rods. The analysis will only be carried out by comparing the value of the displacement at each gusset joint modeling and checking the cross-sectional dimensions of the internal forces that arise with the help of the MIDAS GEN program in modeling the geodesic dome structure which has a diameter of 20000 mm and a height of 10000 mm with the type of steel profile. used is a pipe profile using two types of geodesic dome, namely type 2V and 3V. For loads that are calculated, namely dead load, live load, and wind load. The results showed a relatively small difference in translational displacement and the axial force was relatively the same in the internal force analysis, so it is better if the analysis by modeling the gusset connection as rigid.ABSTRAKKubah geodesik terdiri dari elemen batang baja yang disambung menjadi satu kesatuan struktur. Umumnya kubah geodesik ini dianalisis dengan menganggap sambungan titik buhulnya berupa sendi dan hanya menerima gaya aksial saja pada batang - batangnya. Namun pada kenyataannya untuk mengaplikasikan sambungan titik buhul sebagai sendi murni pada konstruksi tidaklah mudah. Penelitian ini akan menganalisis kubah geodesik dengan memodelkan sambungan titik buhulnya sebagai sendi dimana hanya ada gaya aksial saja yang timbul pada batang - batangnya dan memodelkan titik buhulnya rigid dimana akan terjadi juga momen dan geser pada batang tersebut. Analisis hanya akan dilakukan dengan membandingkan nilai dari perpindahan pada setiap pemodelan sambungan titik buhul dan pengecekan dimensi penampang terhadap gaya – gaya dalam yang timbul dengan bantuan program MIDAS GEN dalam memodelkan struktur kubah geodesik yang mempunyai diameter 20000 mm dan tinggi 10000 mm dengan jenis profil baja yang digunakan adalah profil pipa dengan menggunakan dua tipe kubah geodesik yaitu tipe 2V dan 3V. Untuk beban yang diperhitungkan yaitu beban mati, beban hidup, dan beban angin. Hasil penelitian menunjukkan nilai perbedaan yang relatif kecil pada perpindahan translasi dan diperoleh gaya aksial yang relatif sama pada analisis gaya dalam yang timbul, sehingga sebaiknya analisis dengan pemodelan sambungan titik buhul sebagai rigid.

NEAR HYDRATION OF SINGLY CHARGED MONOATOMIC IONS IN EXTREMELY DILUTED SOLUTIONS: THE EFFECT OF TEMPERATURE AND PRESSURE

The diffusion coefficient and the distance of translational displacement of Li+, Na+ K+, Cs+, Cl– and Br– ions in water at 298.15 K – 423.15 K (25 K step) and pressure from 0.0981 to 784.5 MPa (98.1 MPa step) were calculated from the literature data on limiting molar electrical conductivity. The values for these ions increase with pressure growth from 0.0981 to 98.1 MPa at 298.15 K. Further pressure increase (up to 785 MPa) leads to decrease in . Temperature growth under isobaric conditions leads to an increase in . Parameter (– ri) (deviation from the Stokes–Einstein law, ri is ion structural radius) was used as a criterion for the type of ion solvation. It is shown that Li+ and Na+ ions behave as cosmotropes, or positively solvated structure–forming ions having (– ri) > 0. The Cs+, Cl–, Br– ions behave as chaotropes, or negatively solvated structure–breaking ions having (– ri) < 0. For the K+ ion, the (– ri) deviation is alternating. At 0.0981 MPa and 298.15 K, the K+ ion is a chaotrope. But at 320 K (Tlim) parameter (– ri) = 0. It corresponds to the transition from negative to positive solvation. Above Tlim at P = const, the K+ ion is a cosmotrope. At 298.15 K and up to 98.1 MPa, the pressure causes the same change in the (– ri) deviation as the temperature. On the contrary, at 320 K and higher, the pressure affects the near hydration in the direction opposite to the temperature.

Mechanically Transduced Immunosorbent Assay To Measure Protein-Protein Interactions

Measuring protein-protein interaction (PPI) affinities is fundamental to biochemistry. Yet, conventional methods rely upon the law of mass action and cannot measure many PPIs due to a scarcity of reagents and limitations in the measurable affinity ranges. Here we present a novel technique that leverages the fundamental concept of friction to produce a mechanical signal that indicates binding. The mechanically transduced immunosorbent (METRIS) assay utilizes rolling magnetic probes to measure PPI interaction affinities. METRIS measures the translational displacement of protein-coated particles on a protein-functionalized substrate. The translational displacement scales with the effective friction induced by a PPI, thus producing a mechanical signal when a binding event occurs. The METRIS assay uses as little as 20 pmols of reagents to measure a wide range of affinities while exhibiting a high resolution and sensitivity. Here we use METRIS to measure several PPIs that were previously inaccessible using traditional methods, providing new insights into epigenetic recognition.

ANALISIS KEKUATAN MEKANIK DESAIN BEJANA MOLECULAR SIEVE

ANALISIS KEKUATAN MEKANIK DESAIN BEJANA MOLECULAR SIEVE. Reaktor Daya Eksperimental (RDE) menggunakan bahan bakar bola (pebble) dan gas helium sebagai pendingin primernya. Untuk mempertahankan dan menjaga kualitas helium sebagai pendingin sesuai persyaratannya maka dirancang fasilitas Sistem Pemurnian Helium (SPH). Salah satu bagian dari komponen utama fasilitas Sistem Pemurnian Helium ini adalah bejana molecular sieve. Fungsi dari molecular sieve ini untuk menyerap gas CO2, CH4, dan H2O. Tujuan penelitian ini adalah untuk mengetahui kemampuan kekuatan mekanik dari bejana molecular sieve melalui simulasi menggunakan software Computer Aided Three-dimensional Interactive Application (CATIA). Tahapan yang dilakukan dalam menganalisis kekuatan mekanik desain molecular sieve meliputi : pembuatan model 3-dimensi, memasukkan data sifat mekanik material SS304, serta mensimulasikan pengoperasian pada tekanan uji dan temperatur bervariasi. Pada tekanan 30 bar dan temperatur 120 °C tegangan mekanik yang dihasilkan sebesar 4,4608 x 107 N/m2 lebih kecil daripada yield strenght material SS 304 dan berada di daerah elastis material. Sedangkan translational displacement sebesar 1,1375 mm sangat kecil jika dibandingkan dengan dimensi bejana molecular sieve sehingga tidak mengakibatkan perubahan bentuk. Dengan demikian bejana molecular sieve aman untuk dioperasikan guna mendukung penelitian pemurnian helium Kata kunci: bejana molecular sieve, tegangan mekanik, translational displacement, CATIA

Analysis of the Compressibility Effect of Overburden in a Deep Shield Tunnel Based on the Effect of the Pressure Arch

With the continuous improvement of the planning system for urban subway construction, shield tunnels are being more frequently constructed, and thus, the floating problem of shield tunnels in construction has been paid increasingly more attention. In view of this, in this paper, with the combination of numerical simulation and theoretical analysis, the problem of floating segments compressing the overburden in the deep shield tunnel is discussed. The influential factors of the pressure arch effect are analysed using numerical simulation, the compressive displacement of soil in the plastic zone is investigated in a focused manner based on the pressure arch effect, and the problem of floating segments that the Mindlin solution is applied to under the actions of distributed force and concentrated force is solved. The results show the following: (1) the displacement of the segment is composed of the shield tail gap, the compressive displacement of the soil, and the translational displacement of the soil; (2) the intensity of the pressure arch effect is interactively influenced by the thickness-diameter ratio and the soil properties; (3) the compressive displacement of the soil mass accounts for a larger proportion of floating segment-induced displacements; and (4) the perturbation influence calculation formula of the surrounding strata and the building structure is obtained based on the Mindlin solution.

Type Synthesis of Multi-Loop Spatial Mechanisms With Three Translational Output Parameters Based on Virtual-Loop Theory and Assur Groups

SummaryThis paper presents a new approach to synthesize multi-loop mechanisms with three translational displacement parameters based on virtual-loop theory and Assur groups. The approach used kinematic links as a generalized link group added one-by-one to the output link, which further extends the unified link groups in the plane and space. Firstly, the concept of infinitesimal displacement parameters is introduced to describe the displacement parameters. The dependence on the change in the degree of freedom (DOF) and displacement parameters of the output link after adding a 0-DOF generalized link group is established. Then, the link groups with three displacement parameters are synthesized, and the intersection operation rules are given. The single-loop mechanism is synthesized under two circumstances. The 1-, 2-, and 3-DOF dual-loop mechanisms are obtained by adding corresponding generalized link groups. Finally, the multi-loop mechanisms are obtained by adding corresponding generalized link groups. Some novel mechanisms are synthesized to illustrate the effectiveness of the proposed approach.

Stabilization of a viscoelastic Timoshenko beam fixed into a moving base

In this paper, we are concerned with a cantilevered Timoshenko beam. The beam is viscoelastic and subject to a translational displacement. Consequently, the Timoshenko system is complemented by an ordinary differential equation describing the dynamic of the base to which the beam is attached to. We establish a control force capable of driving the system to the equilibrium state with a certain speed depending on the decay rate of the relaxation function.