Principal Building Research Articles

Tetracopper(II) Cores Driven by an Unexplored Trifunctional Aminoalcohol Sulfonic Acid for Mild Catalytic C–H Functionalization of Alkanes

Three new tetracopper(II) coordination compounds were easily generated from Cu(NO3)2, a trifunctional aminoalcohol sulfonic acid (H3bes, N,N-bis(2-hydroxyethyl)-2-aminoethanesulfonic acid) as a principal building block, and a benzene carboxylic acid as a supporting ligand (i.e., benzoic (Hba), 4-hydroxybenzoic (Hfba), or 3-hydroxybenzoic (Hthba) acid). The obtained microcrystalline products, [Cu4(µ-Hbes)3(µ-H2bes)(µ-L)]·2H2O (L = ba− (1), fhba− (2), and thba− (3)), were fully characterized by FTIR (Fourier-transform infrared spectroscopy), elemental analysis, ESI-MS (Electrospray Ionisation Mass Spectrometry), and single-crystal X-ray diffraction methods. Compounds 1–3 were applied as effective homogeneous catalysts in the oxidative C−H functionalization of alkanes (cycloalkanes and propane). Two different model reactions were explored: (1) mild oxidation of alkanes with hydrogen peroxide to give alcohols and ketones, and (2) mild carboxylation of alkanes with carbon monoxide, water, and potassium peroxodisulfate to give carboxylic acids. For these reactions, effects of different parameters, as well as mechanistic and selectivity characteristics, were studied.

Wind tunnel and delayed detached eddy simulation investigation of interference between two tall buildings

In urban areas, the wind load on a tall building is significantly influenced by the nearby building. The neighboring buildings change the dynamics of the incident flow, which affects the distribution of load on the principal building. The wind-induced loads under the effect of interference may amplify or shield depending on various factors. The present work first examines the impact of height ratios of the interfering building through wind-tunnel tests. The characteristics of time-mean and fluctuating forces for aerodynamically modified tapered twin buildings (having the same shape and size) are analyzed. Second, in the last section, it adopts a delayed detached eddy simulation–based numerical simulation approach to study the flow field in tandem, parallel, and staggered arrangements of square buildings. The results show that as the height of the interfering building decreases, the shielding effect decreases. It obtains the regression equations of interference factor from the best-fit curve.

On the principal building blocks of Mars and Earth

The terrestrial planets are believed to have been formed from primitive material sampling a broad region of the inner solar system. Several meteoritic mixing models attempting to reconcile isotopic characteristics of Mars and Earth have been proposed, but, because of the inherent non-uniqueness of these solutions, additional independent observations are required to resolve the question of the primary building blocks of the terrestrial planets. Here, we consider existing isotopic measurements of Δ′17O, ϵ48Ca, ϵ50Ti, ϵ54Cr, ϵ62Ni, and ϵ84Sr for primitive chondrites and differentiated achondrites and mix these stochastically to reproduce the isotopic signatures of Mars and Earth. For both planets we observe ∼ 105 unique mixing solutions out of 108 random meteoritic mixtures, which are categorised into distinct clusters of mixtures using principal component analysis. The large number of solutions implies that isotopic data alone are insufficient to resolve the building blocks of the terrestrial planets. To further discriminate between isotopically valid mixtures, each mixture is converted into a core and mantle component via mass balance for which geophysical properties are computed and compared to observations. For Mars, the geophysical parameters include mean density, mean moment of inertia, and tidal response, whereas for Earth upper mantle Mg/(Mg+Fe) ratio and core size are employed. The results show that Mars requires an oxidised, FeO-rich differentiated object next to chondritic material as main building blocks. In contrast, Earth's origin remains enigmatic. From a redox perspective, it appears inescapable that enstatite chondrite-like matter constitutes a dominant proportion of the building blocks from which Earth is made. The apparent need for compositionally distinct building blocks for Mars and Earth suggests that dissimilar planetesimal reservoirs were maintained in the inner Solar System during accretion.

New Copper(II) Coordination Compounds Assembled from Multifunctional Pyridine-Carboxylate Blocks: Synthesis, Structures, and Catalytic Activity in Cycloalkane Oxidation.

Two new copper(II) coordination compounds, namely a 1D coordination polymer [Cu(µ-cpna)(phen)(H2O)]n (1) and a discrete tetracopper(II) derivative [Cu(phen)2(H2O)]2[Cu2(µ-Hdppa)2(Hdppa)2] (2), were hydrothermally synthesized from copper(II) chloride as a metal source, 5-(4-carboxyphenoxy)nicotinic acid (H2cpna) or 5-(3,4-dicarboxylphenyl)picolinic acid (H3dppa) as a principal building block, and 1,10-phenanthroline (phen) as a crystallization mediator. Compounds 1 and 2 were isolated as air-stable microcrystalline solids and fully characterized by elemental and thermogravimetric analyses, IR spectroscopy, powder and single-crystal X-ray diffraction. In the solid state, the structure of 1 discloses the linear interdigitated 1D coordination polymer chains with the 2C1 topology. The crystal structure of an ionic derivative 2 shows that the mono- and dicopper(II) units are extended into the intricate 1D hydrogen-bonded chains with the SP 1-periodic net (4,4)(0,2) topology. Thermal stability and catalytic properties of 1 and 2 were also investigated. In fact, both Cu derivatives act as efficient homogeneous catalysts (catalyst precursors) for the mild oxidation of cycloalkanes by hydrogen peroxide to give the corresponding alcohols and ketones; the substrate scope and the effects of type and amount of acid promoter as well as bond-, regio-, and stereo-selectivity features were investigated.

Something interacting and solvable in 1D

We present a two-parameter family of exactly solvable quantum many-body systems in one spatial dimension containing the Lieb–Liniger model of interacting bosons as a particular case. The principal building block of this construction is the previously-introduced (Stouten et al 2018 arXiv:1712.09375) family of two-particle scattering matrices. We discuss an transformation connecting the models within this family and make a correspondence with generalized point interactions. The Bethe equations for the ground state are discussed with a special emphasis on ‘non-interacting modes’ connected by the modular subgroup of . The bound state solutions are discussed and are conjectured to follow some correlated version of the string hypothesis. The excitation spectrum of the new models in this family is derived in analogy to the Lieb–Liniger model and we show that for certain choices of parameters a spectrum inversion occurs such that the Umklapp solutions become the new ground state.

Detached-eddy simulation of interference between buildings in tandem arrangement

In the present study, a computational analysis is performed for the interference between two square tall buildings (with 1:1:7 geometric ratios) arranged in tandem locations and exposed to the turbulent atmospheric boundary layer. The separation ratio (S=X/b, S = centre to centre distance between buildings, b = width of the building) between the buildings varies between 1.5 and 10. The characteristics of forces and modification in the flow field due to the interfering building are analyzed and discussed. Flow conditions at the pedestrian level are evaluated in terms of amplification factor (K), which is categorized as strong, low and tolerable wind condition. Transient three-dimensional numerical simulations are carried out using Delayed Detached-eddy Simulation technique, which is an improved version of the Detached-eddy Simulation approach. Different flow regimes around the buildings are analyzed and the results indicate that in tandem arrangements, the principal building is shielded by the upstream building which consequently reduces the mean along wind forces and strong wind at the pedestrian level.

New Topologically Unique Metal-Organic Architectures Driven by a Pyridine-Tricarboxylate Building Block

Two new three-dimensional (3D) coordination compounds, namely a lead(II) coordination polymer (CP) {[Pb3(µ5-cpta)(µ6-cpta)(phen)2]·2H2O}n (1) and a zinc(II) metal-organic framework (MOF) {[Zn2(µ4-cpta)(µ-OH)(µ-4,4′-bipy)]·6H2O}n (2), were hydrothermally assembled from 2-(5-carboxypyridin-2-yl)terephthalic acid (H3cpta) as an unexplored principal building block and aromatic N,N-donors as crystallization mediators. Both products were isolated as air-stable microcrystalline solids and were fully characterized by IR spectroscopy, elemental and thermogravimetric analysis, and powder and single-crystal X-ray diffraction. Structural and topological features of CP 1 and MOF 2 were analyzed in detail, allowing to identify a topologically unique 4,5,5,6-connected net in 1 or a very rare 4,4-connected net with the isx topology in 2. Thermal stability and solid-state luminescent behavior of 1 and 2 were also investigated. Apart from revealing a notable topological novelty, both compounds also represent the first structurally characterized Pb(II) and Zn(II) derivatives assembled from H3cpta, thus opening up the application of this unexplored pyridine-tricarboxylate block in the design of new metal-organic architectures.

Physicochemical and mechanical study of Mayan Archeological stony constructive materials

Mayan civilization monumental architecture has been a vital source of information to gain acknowledgement about its way of life, science and political hierarchy; consequently, examination of constructive materials of Mayan structures by using materials science characterization techniques are noteworthy. This work focuses on the study and characterization of archeological stony materials taken from the main structure on Witzinah archeological site located south of Yucatan, Mexico, in order to determine its constituted elements and chemical components. Such materials were observed under scanning electron microscopy (SEM) to establish, in accord to its micro-structural patterns, the porosity and morphology, and energy-dispersive X-ray spectroscopy (EDX) to determine the chemical compounds. Calorimetric analysis through TGA was carried out in order to identify the presence of organic elements as well as Infrared analysis (FTIR) and nuclear magnetic resonance (1H NMR) to detect polymeric components. Preliminary results indicated that mortars contain saturated fats (esters) that were possibly originated by degradation of natural polymer (elastomeric rubber) known as polyisoprene as well as nano-clay material named Palygorskita (typified in Maya as Sak lu’um), and that both had a direct influence on the properties of the evaluated mortars used for the construction of the site Principal Building.

Cellulose crystals plastify by localized shear.

Cellulose microfibrils are the principal structural building blocks of wood and plants. Their crystalline domains provide outstanding mechanical properties. Cellulose microfibrils have thus a remarkable potential as eco-friendly fibrous reinforcements for structural engineered materials. However, the elastoplastic properties of cellulose crystals remain poorly understood. Here, we use atomistic simulations to determine the plastic shear resistance of cellulose crystals and analyze the underpinning atomic deformation mechanisms. In particular, we demonstrate how the complex and adaptable atomic structure of crystalline cellulose controls its anisotropic elastoplastic behavior. For perfect crystals, we show that shear occurs through localized bands along with noticeable dilatancy. Depending on the shear direction, not only noncovalent interactions between cellulose chains but also local deformations, translations, and rotations of the cellulose macromolecules contribute to the response of the crystal. We also reveal the marked effect of crystalline defects like dislocations, which decrease both the yield strength and the dilatancy, in a way analogous to that of metallic crystals.

Across-wind excitation mechanism for interference of twin tall buildings in staggered arrangement

This paper explores the excitation mechanism for across-wind force interference of two tall buildings in staggered arrangement through detailed measurement of turbulent flow fields past the two buildings and concurrent pressure measurement on the downstream principal building. Analysis of the instantaneous flow fields and wall pressure distributions reveals a synchronization process between the sideway oscillation of the upstream building wake with vortex development and shedding from the downstream principal building. Further analysis using the phase averaging technique confirms that the synchronization of five quasi-periodic aerodynamic phenomena is responsible for the magnification of across-wind force fluctuations in a region of building arrangements centered at a longitudinal building separation of 5 building breaths (D) and a lateral separation of 2.5D. In addition to this “wake interference region I”, three other flow regions of staggered arrangement are classified, namely, “wake interference region II” in which wake development on the principal building is affected by impingement of the meandering upstream building wake in a close lateral separation, “proximity interference region” which is characterized by channeled flow through a narrow gap between the two buildings, and “weak interference region”.

Effect of building proximity on external and internal pressures under tornado-like flow

Tornadoes are one of the world\'s deadliest natural phenomena. They are characterized by short life span and danger. It has been observed through post-damage surveys that localities with large numbers of buildings suffer major damage during a tornado attack resulting in huge loss of life and property. Thus,it is important to study interfering buildings exposed to tornado-like vortices. The present study focuses on external and internal pressures developed on building models exposed to translating tornado-like vortices in the presence of an interfering building model. The effects of translating speed and swirl ratio of a tornado-like vortex on external and internal pressures for a principal building in the vicinity of an interfering building are investigated. Results indicate that external and internal pressures are enhanced or reduced depending on the location of the interfering building with respect to the principal building.

Self-assembled 3D heterometallic Zn(II)/K(I) metal–organic framework with the fluorite topology

Treatment of zinc(II) acetate with a ditopic (bis-tridentate) thiocarbazone {H2L, bis(pyridine-2-aldehyde) thiocarbazone} as a principal building block and potassium thiocyanate as a source of auxiliary ligand resulted in the self-assembly generation of a novel heterometallic Zn(II)/K(I) metal–organic framework (MOF) formulated as [Zn2(L)K2(µ2-H2O)2(µ2-SCN)4]n (1). It was isolated as a microcrystalline solid and fully characterized, including by single crystal X-ray diffraction. Crystal structure of 1 reveals a very intricate 3D framework assembled from the [Zn2L]2+ and [K2(µ2-H2O)2]2+ secondary building units (SBUs) and multiple µ2-thiocyanate linkers. Topological analysis of the simplified underlying net of 1 disclosed a binodal 4,8-connected framework with the flu (fluorite) topology. Synthesis, characterization, structural and topological features, as well as Hirshfeld surface analysis are discussed in the present study.

Interplay between H-bonding and interpenetration in an aqueous copper(ii)-aminoalcohol-pyromellitic acid system: self-assembly synthesis, structural features and catalysis.

Two new copper(ii) coordination compounds, [Cu(H1.5mdea)2]2(H2pma) (1a) and [{Cu2(μ-Hmdea)2}2(μ4-pma)]n·2nH2O (1b), were self-assembled at different temperatures from the same multicomponent reaction system, comprising copper(ii) nitrate, N-methyldiethanolamine (H2mdea), pyromellitic acid (H4pma), and potassium hydroxide. Products 1a and 1b were isolated as microcrystalline solids and fully characterized and their structures were established by single-crystal X-ray diffraction. Compound 1a features the bis-aminoalcohol(ate) monocopper(ii) units and H2pma2- anions that are multiply interconnected by strong H-bonds into a firm 2D H-bonded layer. Compound 1b reveals the bis-aminoalcoholate dicopper(ii) motifs that are interlinked by the μ4-pma4- spacers into a 3D + 3D interpenetrated metal-organic framework. From a topological perspective, both networks of 1a and 1b are uninodal and driven by similar 4-connected H2pma2- or pma4- nodes, but result in distinct sql and dia topologies, respectively. Compound 1a was applied as an efficient catalyst for two model cycloalkane functionalization reactions: (1) oxidation by H2O2 to form cyclic alcohols and ketones and (2) hydrocarboxylation by CO/H2O and S2O82- to form cycloalkanecarboxylic acids. The substrate scope, effects of various reaction parameters, selectivity and mechanistic features were also investigated.

A new series of Co, Ni, Zn, and Cd metal-organic architectures driven by an unsymmetrical biphenyl-tricarboxylic acid: hydrothermal assembly, structural features and properties.

This study reports the hydrothermal synthesis of a novel series of twelve coordination compounds, namely, {[Cd(μ-Hnbtc)(H2O)4]·H2O}n (1), [Zn2(μ-Hnbtc)2(phen)2]·2H2O (2), [Zn(Hnbtc)(phen)2(H2O)]·4.5H2O (3), [Ni(Hnbtc)(phen)2(H2O)]·6H2O (4), [Zn2(μ-Hnbtc)2(2,2'-bipy)2]·2H2O (5), [Cd3(μ5-nbtc)(μ6-nbtc)(2,2'-bipy)2(H2O)]n (6), {[Zn3(μ3-nbtc)2(phen)3(H2O)2]·4H2O} (7), [Co(H2O)6][Co2(nbtc)2(μ-4,4'-bipy)(4,4'-bipy)2(H2O)6]·8H2O (8), {[Ni3(μ4-nbtc)2(μ-4,4'-bipy)2.5(μ-H2O)(H2O)3]·4H2O}n (9), {[Cd2(μ4-nbtc)(μ-OH)(2,2'-bipy)2]·H2O}n (10), [Cd2(μ4-nbtc)(μ-OH)(phen)2(H2O)]n (11), and {[Zn2(μ5-nbtc)(μ3-OH)(μ-4,4'-bipy)]·4,4'-bipy·H2O}n (12), which are derived from 3'-nitro-biphenyl-2,4,4'-tricarboxylic acid (H3nbtc) as a virtually unexplored building block. These compounds were generated in aqueous medium from the corresponding metal(ii) chlorides as a metal source, H3nbtc as a principal building block, NaOH as a base, and simple N,N-donor aromatic ligands as crystallization mediators (i.e., 1,10-phenanthroline, phen; 2,2'-bipyridine, 2,2'-bipy; or 4,4'-bipyridine, 4,4'-bipy). All products 1-12 were completely characterized in the solid state by IR spectroscopy, elemental and thermogravimetric (TGA) analyses, powder (PXRD) and single-crystal X-ray diffraction. Structures of 1-12 range from discrete 0D dimers (2 and 5) or monomers (3, 4, and 8) to 1D coordination polymers (CPs, 1, 6, 7, 10, and 11) and 3D metal-organic frameworks (MOFs, 9 and 12). A broad structural diversity of 1-12 is guided by the type of the metal(ii) node, the molar ratio between H3nbtc and sodium hydroxide, and the kind of crystallization mediator. Topological analysis and classification of metal-organic underlying nets was made, disclosing the following topological types: 2C1 (in 1 and 7), 1M2-1 (in 2 and 5), SP1-periodic net (in 10 and 11), tfz-d (in 12), and some topologically unique nets (in 6 and 9). Luminescence behavior of 1-3, 5-7, and 10-12 was studied in the solid state. Magnetic properties of a Ni(ii) MOF 9 were also investigated and modeled. All obtained products 1-12 represent the first structurally characterized examples of coordination compounds derived from H3nbtc, thus opening up its application in coordination chemistry as a novel tricarboxylate building block.

Interference effects of an adjacent tall building with various sizes on local wind forces acting on a tall building

This article focuses on variations of local wind forces along height levels of a tall building due to an adjacent tall building with various height and breadth ratios through huge wind tunnel experiments. It deals with the characteristics of local wind forces including root mean square local wind force coefficients, non-dimensional power spectra, and root coherences along height levels of a tall building with an adjacent tall building in critical locations. It is shown that increases of over 20% in interference factors ( MIFMD, RIFMD, and RIFML) for maximum mean and root mean square base overturning moment coefficients in along- and across-wind directions occur when the adjacent building is close to the principal building. Higher and wider adjacent buildings can cause not only higher mean wind loads but also higher dynamic wind loads in along- and across-wind directions, but the critical locations of an adjacent building with various height and breadth ratios are somewhat different. However, most critical locations of an adjacent building for wind-induced wind loads are within the region ( X/ B, Y/ B) = (1.5, 0–1.5).

Mining electrical meter data to predict principal building use, performance class, and operations strategy for hundreds of non-residential buildings

This study focuses on the inference of characteristic data from a data set of 507 non-residential buildings. A two-step framework is presented that extracts statistical, model-based, and pattern-based behavior. The goal of the framework is to reduce the expert intervention needed to utilize measured raw data in order to infer information such as building use type, performance class, and operational behavior. The first step is temporal feature extraction, which utilizes a library of data mining techniques to filter various phenomenon from the raw data. This step transforms quantitative raw data into qualitative categories that are presented in heat map visualizations for interpretation. In the second step, a random forest classification model is tested for accuracy in predicting primary space use, magnitude of energy consumption, and type of operational strategy using the generated features. The results show that predictions with these methods are 45.6% more accurate for primary building use type, 24.3% more accurate for performance class, and 63.6% more accurate for building operations type as compared to baselines.

Evolution of the Building Management System in the INFN CNAF Tier-1 data center facility.

The INFN CNAF Tier-1 data center is composed by two different main rooms containing IT resources and four additional locations that hosts the necessary technology infrastructures providing the electrical power and cooling to the facility. The power supply and continuity are ensured by a dedicated room with three 15,000 to 400 V transformers in a separate part of the principal building and two redundant 1.4MW diesel rotary uninterruptible power supplies. The cooling is provided by six free cooling chillers of 320 kW each with a N+2 redundancy configuration. Clearly, considering the complex physical distribution of the technical plants, a detailed Building Management System (BMS) was designed and implemented as part of the original project in order to monitor and collect all the necessary information and for providing alarms in case of malfunctions or major failures. After almost 10 years of service, a revision of the BMS system was somewhat necessary. In addition, the increasing cost of electrical power is nowadays a strong motivation for improving the energy efficiency of the infrastructure. Therefore the exact calculation of the power usage effectiveness (PUE) metric has become one of the most important factors when aiming for the optimization of a modern data center. For these reasons, an evolution of the BMS system was designed using the Schneider StruxureWare infrastructure hardware and software products. This solution proves to be a natural and flexible development of the previous TAC Vista software with advantages in the ease of use and the possibility to customize the data collection and the graphical interfaces display. Moreover, the addition of protocols like open standard Web services gives the possibility to communicate with the BMS from custom user application and permits the exchange of data and information through the Web between different third-party systems. Specific Web services SOAP requests has been implemented in our Tier-1 monitoring system in order to collect historical trends of power demands and calculate the partial PUE (pPUE) of a specific part of the infrastructure. This would help in the identification of “spots” that may need further energy optimization. The StruxureWare system maintains compatibility with standard protocols like Modbus as well as native LonWorks, making possible reusing the existing network between physical locations as well as a considerable number of programmable controller and I/O modules that interact with the facility. The high increase of detailed statistical information about power consumption and the HVAC (heat, ventilation and air conditioning) parameters could prove to be a very valuable strategic choice for improving the overall PUE. This will bring remarkable benefits for the overall management costs, despite the limits of the non-optimal actual location of the facility, and it will help us in the process of making a more energy efficient data center that embraces the concept of green IT.

New lanthanide 2D coordination polymers constructed from a flexible ether-bridged tricarboxylate block: Synthesis, structures and luminescence sensing

Three new 2D lanthanide-organic networks, {[Sm2(µ4-cpta)(µ5-cpta)(H2O)3]·3H2O}n (1) and [Ln(µ3-cpta)(phen)(H2O)2]n (Ln=Tb (2) and Sm (3)), were successfully synthesized via hydrothermal reactions using Ln(NO3)3·6H2O, a flexible ether-bridged tricarboxylic acid H3cpta (2-(2-carboxyphenoxy)terephthalic acid) as a principal building block, and phen (1,10-phenanthroline) as an optional supporting ligand. All products were obtained as air and thermally stable microcrystalline solids and fully characterized by standard solid-state techniques, including elemental analysis, TGA, IR spectroscopy, powder and single-crystal X-ray diffraction. Compound 1 possesses an intricate 2D layer structure with the 4,5L51 topology, which is driven by the µ4- and µ5-cpta3− and Sm(III) nodes. Compounds 2 and 3 are isostructural and disclose a different 2D metal-organic network with the fes topology, which is assembled from the µ3-cpta3− and Ln(III) nodes. Luminescence properties of 2 and derived Mn+@2 suspensions were investigated, disclosing a possible use of this compound as a notable luminescence sensor for the detection of Fe3+ cations in aqueous medium.

Interference effects on tail characteristics of extreme pressure value distributions

This study investigates the interference effects on the tail characteristics of extreme pressure coefficients. Systematic wind tunnel tests are conducted, from which a large amount of data is generated to describe the tail characteristics of extreme pressure coefficients under interference effects. Through the identification of shape parameter of Generalized Extreme Value distribution (GEVD) function and the estimation of fluctuation level of extreme pressures, optimal peak pressure coefficients are predicted to compare with the Cook and Mayne coefficients. Results show that the design fractiles based on estimated parameters are generally lower than 78%, and the identified concave tail characteristics imply a ceiling coefficient value. The largest negative peak pressure coefficients are found when the interfering building is in the upstream region of the principal building and most of them are along the vertical edges of side faces parallel to the wind direction. By calculating the error percentages due to the assumption of Gumbel tail, the estimation bias is indicated and the significances of both the shape parameter and the fluctuation level of extreme pressures are presented.

Effects of aerodynamic modification mechanisms on interference from neighboring buildings

This paper investigates the effect of the single and multiple aerodynamic modification mechanisms on the dynamic behavior of the principal building that is interfered by a very closely located building. For the study, aeroelastic vibration tests and high-frequency force balance tests are conducted to compare responses and wind forces in a well-simulated turbulent boundary layer flow. The principal building is manufactured with three different building configurations to represent the single and multiple aerodynamic modification treatments; the neighboring building which produces interference effects is made into a square prism model. Results show that the multiple modification treatment is efficient in reducing wind forces in all interference location series. However, it is also found that in certain critical conditions, such treatment is sensitive to reduced velocity, and may amplify the interference effect and result in larger displacements.