Bidirectional Response Research Articles

Experiment-based out-of-plane resistance of strong masonry infills for codified applications

In the last two decades, the typology of unreinforced masonry infills to be adopted in newly designed RC structures has been subjected to significant changes, passing from the use of slender/weak masonry panels with one or two layers, to stronger single-whyte walls. These modifications have allowed to reduce the construction time and to improve the thermal and acoustic performance. However, the adoption of a more robust masonry solution can significantly affect the response of infilled structures as respect to slender/weak typologies, but the current standards do not provide proper design procedures for the in-plane and out-of-plane verification of such masonry infills. In order to fill some of these gaps, this paper presents the experimental results of two masonry infills made of modern strong masonry tested only in the out-of-plane direction, without any previous in-plane load. The tests have permitted to apply and analyze the existing formulations in the codes and literature for the computation of the out-of-plane resistance and the fundamental period. Moreover, some new formulations have been proposed to better estimate these values according to the experimental evidence. In the proposed equations, dimensionless parameters have been introduced to include some important physical aspects, such as the bidirectional response of the masonry infill, the second order effects, the deformability of the frame and the occurrence of local mechanisms such as the sliding at the frame/infill interface.

A Highly Sensitive, Reversible, and Bidirectional Humidity Actuator by Calcium Carbonate Ionic Oligomers Incorporated Poly(Vinylidene Fluoride)

AbstractSensitivity and multi‐directional motivation are major two factors for developing optimized humidity‐response materials, which are promising for sensing, energy production, etc. Organic functional groups are commonly used as the water sensitive units through hydrogen bond interactions with water molecules in actuators. The multi‐coordination ability of inorganic ions implies that the inorganic ionic compounds are potentially superior water sensitive units. However, the particle forms of inorganic ionic compounds produced by classical nucleation limit the number of exposed ions to interact with water. Recent progress on the inorganic ionic oligomers has broken through the limitation of classical nucleation, and realized the molecular‐scaled incorporation of inorganic ionic compounds into an organic matrix. Here, the incorporation of hydrophilic calcium carbonate ionic oligomers into hydrophobic poly(vinylidene fluoride) (PVDF) is demonstrated. The ultra‐small calcium carbonate oligomers within a PVDF film endow it with an ultra‐sensitive, reversible, and bidirectional response. The motivation ability is superior to other bidirectional humidity‐actuators at present, which realizes self‐motivation on an ice surface, converting the chemical potential energy of the humidity gradient from ice to kinetic energy.

Unidirectional response to bidirectional selection on body size II. Quantitative genetics

Anticipating the genetic and phenotypic changes induced by natural or artificial selection requires reliable estimates of trait evolvabilities (genetic variances and covariances). However, whether or not multivariate quantitative genetics models are able to predict precisely the evolution of traits of interest, especially fitness‐related, life history traits, remains an open empirical question. Here, we assessed to what extent the response to bivariate artificial selection on both body size and maturity in the medaka Oryzias latipes, a model fish species, fits the theoretical predictions. Three lines (Large, Small, and Control lines) were differentially selected for body length at 75 days of age, conditional on maturity. As maturity and body size were phenotypically correlated, this selection procedure generated a bi‐dimensional selection pattern on two life history traits. After removal of nonheritable trends and noise with a random effect (“animal”) model, the observed selection response did not match the expected bidirectional response. For body size, Large and Control lines responded along selection gradients (larger body size and stasis, respectively), but, surprisingly, the Small did not evolve a smaller body length and remained identical to the Control line throughout the experiment. The magnitude of the empirical response was smaller than the theoretical prediction in both selected directions. For maturity, the response was opposite to the expectation (the Large line evolved late maturity compared to the Control line, while the Small line evolved early maturity, while the opposite pattern was predicted due to the strong positive genetic correlation between both traits). The mismatch between predicted and observed response was substantial and could not be explained by usual sources of uncertainties (including sampling effects, genetic drift, and error in G matrix estimates).

Bidirectional Response of Weak-Axis End-plate Moment Connections: Numerical Approach

Brittle failure mechanisms can affect the seismic performance of structures composed of intersecting moment resisting frames, if the biaxial effects are not considered. In this research, the bidirectional cyclic response of H-columns with weak-axis moment connections was studied using numerical models. Several configurations of joints with bidirectional effects and variable axial loads were studied using the finite element method (FEM) in ANSYS v17.2 software. The results obtained showed a ductile behavior when cyclic loads are applied. No evidence of brittle failure mechanisms in the studied joint configurations was observed, in line with the design philosophy established in current seismic provisions. However, beams connected to the column minor axis reached a partially restrained behavior. Joints with four beams connected to the column exhibited a partially restrained behavior for all axial load levels. An equivalent force displacement method was used to compare the hysteretic response of 2D and 3D joints, obtaining higher deformations in 3D joints with respect to 2D joints with a similar number of connected beams. Consequently, design procedures are not capable of capturing the 3D deformation phenomenon.

Excellent performance in vertical graphene-C60-graphene heterojunction phototransistors with a tunable bi-directionality

Array integrated all-carbon phototransistor with high photoconductive gain and fast response speed is very attractive for researchers to realize broadband and tunable photo-imaging. Generally, the photoresponse is limited by the low light absorption of carbon materials while the detector array is limited by processing technology. Here, we patterned vertical graphene-C60-graphene heterojunction using photolithograph and deep reactive ion etching method to achieve a sensitive (3.4×105A/W), fast (23 ms) and broadband (405 nm–1550 nm) response. More interestingly, a bi-directional response photocurrent (positive and negative) has been observed, and the response intensity, speed and direction could adjust by changing gate voltage. The different charges transfer mechanism of positive and negative response of fabricated vertical heterojunction device was explored. What’ more, we fabricated 250×250 vertical graphene/C60 film/graphene phototransistors array, which made it possible to realize a large-scale array detection in wide band with all-carbon material.

Performance of a 3D pendulum tuned mass damper in offshore wind turbines under multiple hazards and system variations

Misaligned wind-wave and seismic loading render offshore wind turbines suffering from excessive bi-directional vibration. However, most of existing research in this field focused on unidirectional vibration mitigation, which is insufficient for research and real application. Based on the authors\' previous work (Sun and Jahangiri 2018), the present study uses a three dimensional pendulum tuned mass damper (3d-PTMD) to mitigate the nacelle structural response in the fore-aft and side-side directions under wind, wave and near-fault ground motions. An analytical model of the offshore wind turbine coupled with the 3d-PTMD is established wherein the interaction between the blades and the tower is modelled. Aerodynamic loading is computed using the Blade Element Momentum (BEM) method where the Prandtl\'s tip loss factor and the Glauert correction are considered. Wave loading is computed using Morison equation in collaboration with the strip theory. Performance of the 3d-PTMD is examined on a National Renewable Energy Lab (NREL) monopile 5 MW baseline wind turbine under misaligned wind-wave and near-fault ground motions. The robustness of the mitigation performance of the 3d-PTMD under system variations is studied. Dual linear TMDs are used for comparison. Research results show that the 3d-PTMD responds more rapidly and provides better mitigation of the bi-directional response caused by misaligned wind, wave and near-fault ground motions. Under system variations, the 3d-PTMD is found to be more robust than the dual linear TMDs to overcome the detuning effect. Moreover, the 3d-PTMD with a mass ratio of 2% can mitigate the short-term fatigue damage of the offshore wind turbine tower by up to 90%.

Genetic influences on the variability of response to repetitive transcranial magnetic stimulation in human pharyngeal motor cortex.

Recent studies have reported substantial variability in response to repetitive transcranial magnetic stimulation (rTMS). We hypothesized that an individual's genetic predisposition may contribute to such variability in the pharyngeal motor cortex. This study aimed to investigate the response to 1 and 5 Hz rTMS paradigms on pharyngeal motor cortex in healthy participants and its relationship with genetic predisposition. Forty-one healthy participants (25.4 ± 4.6 years old) received either or both 1 Hz (n = 39) and 5 Hz rTMS (n = 40) over pharyngeal motor cortex. Pharyngeal and thenar motor-evoked potentials were recorded at baseline and for 1 hour post-rTMS. The participants were then classified according to their response. The associations between rTMS response and gender, time of day of the stimulation, and eight prespecified single nucleotide polymorphisms (SNPs) were analyzed. There was no direction-specific response to either paradigm (1 Hz: F[3.69, 129.21] = 0.78, P = 0.56; 5 Hz: F[4.08, 146.85] = 1.38, P = 0.25). Only 13% of participants showed the expected bidirectional response (inhibition for 1 Hz and excitation for 5 Hz). Significant associations were found between response and COMT (1 Hz: P = 0.03) and DRD2 (1 Hz: P = 0.02; 5 Hz: P = 0.04) polymorphisms. Carriers of minor allele G from SNP rs6269 (COMT) were more likely to show inhibitory or excitatory outcomes after 1 Hz rTMS. By contrast, carriers of minor allele A from SNP rs1800497 (DRD2) were more likely to show no response to 1 Hz rTMS and inhibition after 5 Hz rTMS. Two SNPs from COMT and DRD2 genes may partially explain the response variability to rTMS in the pharyngeal motor system. Further research should focus on stratified approaches for neurostimulatory dysphagia treatment using rTMS.

Energy capacity and seismic performance of RC waffle‐flat plate structures under two components of far‐field ground motions: Shake table tests

SummaryThe bidirectional response of a portion of a reinforced concrete (RC) waffle‐flat plate (WFP) structure subjected to far‐field ground motions is studied through shake table tests. The test specimen is a scaled portion of a prototype structure designed under current building codes and located in a region of moderate seismicity of the Mediterranean area. The specimen was subjected to a sequence of tests of increasing acceleration amplitude that respectively represented very frequent, frequent, design, and very rare earthquakes at the site. The test structure performed well (basically in the elastic domain) under very frequent and frequent earthquakes, approached the boundary between the performance levels of life safety and near collapse under the design earthquake, and collapsed under the very rare earthquake. Damage concentrated at column bases and at the transverse beams of the exterior plate‐to‐column connection. Columns dissipated about 10% of the total energy that contributes to damage, and the rest was dissipated by the exterior plate‐column connection. The total energy input on the structure until collapse under the bidirectional seismic action was very close to the value obtained in previous studies on a similar specimen tested under unidirectional ground motions. The capacity curve estimated from the experimental base shear vs top displacement relationship suggests it is best to use a behavior factor of at most q = 2 when designing WFP structures with the reduced‐spectrum force‐based approach.

Bioinspired low noise circular-shaped MEMS directional microphone

The traditional state-of-the-art miniature directional microphones suffer from a higher noise level mainly due to size constraints. Herein, a miniature directional microphone mimicking the fly Ormia ochracea’s ear anatomy is presented with the prime focus on achieving higher signal-to-noise ratio at reduced size. The microphone has circular shape with aluminum nitride (AlN)-based piezoelectric readout scheme deposited at the center of the diaphragm. The 3-3 transduction mode is adopted for sensitivity enhancement. The microphone testing is performed in an anechoic chamber. Besides the bidirectional response, the A-weighted noise under broadband excitation is ∼29 dBA, which is lower than the optical directional microphone of Miles et al., which is the most prominent noise analysis work in the area of fly inspired MEMS directional microphone.

Bidirectional Role of β2-Adrenergic Receptor in Autoimmune Diseases.

Disorder of the sympathetic nervous system (SNS) is closely related to the pathogenesis of various autoimmune diseases (ADs). Catecholamine triggered beta2-adrenergic receptor (β2-AR) signaling is important in creating a bidirectional response in the progression of ADs due to factors including diverse expression patterns, single nucleotide polymorphisms (SNPs), biased signals, and desensitization of β2-AR, as well as different subtypes of Gα binding to β2-AR. In this review, we summarize the actions of β2-AR signaling in regulating the functions of immunocytes and in the pathogenesis of ADs, and the application of β2-AR agonists or antagonists in treating major types of ADs is also discussed. We suggest that restoring the immune balance via a soft regulation of the expression or activation of β2-AR is one of the promising therapeutic strategies for systematic ADs.

Directional Sound Detection by Sensing Acoustic Flow

The ability to determine the direction of propagation of an acoustic wave is crucial to sound source detection, localization, and identification. Current techniques based on sensing acoustic pressure using membranes at multiple spatial locations tend to have directionality and output sensitivity that depend strongly on the sound frequency, which compromises performance, especially in miniaturized applications. Unlike pressure, which is a scalar, the fluctuating flow of the acoustic medium (i.e., the acoustic particle velocity) is a vector, which inherently contains the direction information of sound propagation. Here, we experimentally demonstrate an alternative, and more direct, method of directional sound detection by sensing acoustic flow using nanofibers, which are driven by viscous forces applied by the fluctuating medium. The measured output signal of this prototype sensor exhibits bidirectional response and flat frequency response across a wide range of frequencies from 100 ${\rm Hz}$ to 10000 ${\rm Hz}$ . While pressure-sensing microphones now enjoy an annual market in the billions of units sold, a broadband sound flow sensor with almost full fidelity will provide considerable benefits.

Estimating seismic response under bi-directional shaking per uni-directional analysis: Identification of preferred angle of incidence

Implications of incidence angle of ground motions on inelastic demand of bridge piers under bi-directional seismic excitation have been studied against the corresponding uni-directional counterparts. Recognizing that the bi-directional analysis is complex and computationally intensive, to improve the use of less-rigorous uni-directional analysis, present study identifies the most and the least preferred orientations for a given pair of horizontal ground motion. We define the most and least preferred orientations, where the difference between bi-directional and uni-directional response is respectively minimized and maximized. These orientations can be uniquely identified for both peak and cumulative demand in terms of appropriate ground motion parameters (energetic length and characteristic intensity respectively for peak and cumulative demand) independent of structural properties. It has been shown that the improved estimate of bi-directional response may be obtained from simplified uni-directional analysis by utilizing these preferred incidence angles in conjunction with appropriate combination rules (30% for peak and 40% for cumulative demand).

Chronic kidney disease with comorbid cardiac dysfunction exacerbates cardiac and renal damage.

To address the pathophysiological mechanisms underlying chronic kidney disease with comorbid cardiac dysfunction, we investigated renal and cardiac, functional and structural damage when myocardial infarction (MI) was applied in the setting of kidney injury (induced by 5/6 nephrectomy—STNx). STNx or Sham surgery was induced in male Sprague–Dawley rats with MI or Sham surgery performed 4 weeks later. Rats were maintained for a further 8 weeks. Rats (n = 36) were randomized into four groups: Sham+Sham, Sham+MI, STNx+Sham and STNx+MI. Increased renal tubulointerstitial fibrosis (P < 0.01) and kidney injury molecule‐1 expression (P < 0.01) was observed in STNx+MI compared to STNx+Sham animals, while there were no further reductions in renal function. Heart weight was increased in STNx+MI compared to STNx+Sham or Sham+MI animals (P < 0.05), despite no difference in blood pressure. STNx+MI rats demonstrated greater cardiomyocyte cross‐sectional area and increased cardiac interstitial fibrosis compared to either STNx+Sham (P < 0.01) or Sham+MI (P < 0.01) animals which was accompanied by an increase in diastolic dysfunction. These changes were associated with increases in ANP, cTGF and collagen I gene expression and phospho‐p38 MAPK and phospho‐p44/42 MAPK protein expression in the left ventricle. Addition of MI accelerated STNx‐induced structural damage but failed to significantly exacerbate renal dysfunction. These findings highlight the bidirectional response in this model known to occur in cardiorenal syndrome (CRS) and provide a useful model for examining potential therapies for CRS.

Behaviour of steel cushions subjected to combined actions

Mild steel is relatively low-cost and easily accessible material to fabricate some structural members. It would be a significant advantage if seismic energy dissipaters that are used in structures constructed in the earthquake prone areas, could also be produced on site. In this paper, a promising seismic energy dissipater made of mild steel, so-called steel cushion (SC) is presented. It is provided experimental and analytical responses of SCs subjected to bi-axial loadings. SC rolls under the lateral loading that allows relocation of the plasticized cross-section. Henceforth, SC dissipates considerable amount of seismic energy. A series of tests were performed to achieve experimentally the behavior of SC subjected to longitudinal and transversal loading. Finite Element Models (FEMs) were also generated to reproduce the experimental backbone curves and to predict the bi-directional response properties for discrete transversal forces and plate thicknesses. Closed-form equations were derived to determine yield and ultimate forces and the corresponding displacements as well as location of the plasticized sections. The behavior of SC could either be projected by the FEMs with the exhibited parameters or by means of the proposed closed-form equations and the normalized design chart.

Bovine embryo-oviduct interaction in vitro reveals an early cross talk mediated by BMP signaling.

Signaling components of bone morphogenetic proteins (BMPs) are expressed in an anatomically and temporally regulated fashion in bovine oviduct. However, a local response of this signaling to the presence of the embryo has yet to be elucidated. The aim of the present study was to evaluate if early embryo-oviduct interaction induces changes in the gene expression of BMP signaling components. For this purpose, we used an in vitro co-culture system to investigate the local interaction between bovine oviductal epithelial cells (BOEC) from the isthmus region with early embryos during two developmental periods: before (from the 2-cell to 8-cell stage) or during (from the 8-cell to 16-cell stage) the main phase of embryonic genome activation (EGA). Exposure to embryos, irrespective of the period, significantly reduced the relative abundance of BMPR1B, BMPR2, SMAD1, SMAD6 and ID2 mRNAs in BOEC. In contrast, embryos that interacted with BOEC before EGA showed a significant increase in the relative abundance of SMAD1 mRNA at the 8-cell stage compared to embryos cultured without BOEC. Moreover, embryos at the 16-cell stage that interacted with BOEC during EGA showed a significant increase in BMPR1B, BMPR2 and ID2 mRNA. These results demonstrate that embryo-oviduct interaction in vitro induces specific changes in the transcriptional levels of BMP signaling, causing a bidirectional response that reduces the expression levels of this signaling in the oviductal cells while increases them in the early embryo. This suggests that BMP signaling pathway could be involved in an early cross talk between the bovine embryo and the oviduct during the first stages of development.

Characterization of radial and circumferential mechanical energy components in bi-directional nonlinear seismic response of steel bridge piers

In this study, the bi-directional nonlinear elaso-plastic seismic response of steel bridge piers subjected to bi-directional ground motions is analyzed with a particular interest in the role of the radial and circumferential components of mechanical energy. In order to explore the influencing factors to the maximum bi-directional seismic response, dynamic characteristics of a circular steel bridge pier are expressed by two modeling techniques: the multiple shear spring (MSS) model, and the fiber model. The calculated bi-directional dynamic responses of the steel bridge pier models under artificially generated bi-directional ground motions are characterized by introducing a technique to divide the strain and kinetic energies to the radial and circumferential components. The analysis result indicates that the level of circumferential strain energy that effectively contributes to dissipation of the total kinetic energy is of great importance in assessing the maximum bi-directional response. When the two models are subjected to the identical bi-directional ground motion, the circumferential strain energy induced in the fiber model is higher than that obtained by the multiple shear spring model, resulting in smaller radial displacement. Also, the analyses of the fiber model for various cases of directivity property of the input bi-directional seismic ground motion show that the bi-directional response is smaller than the unidirectional response in some cases. The reason can be explained by higher circumferential strain energy which can be related to the reduction of radial displacement in those cases.

KMEn: Analyzing noisy and bidirectional transcriptional pathway responses in single subjects

MotivationUnderstanding dynamic, patient-level transcriptomic response to therapy is an important step forward for precision medicine. However, conventional transcriptome analysis aims to discover cohort-level change, lacking the capacity to unveil patient-specific response to therapy. To address this gap, we previously developed two N-of-1-pathways methods, Wilcoxon and Mahalanobis distance, to detect unidirectionally responsive transcripts within a pathway using a pair of samples from a single subject. Yet, these methods cannot recognize bidirectionally (up and down) responsive pathways. Further, our previous approaches have not been assessed in presence of background noise and are not designed to identify differentially expressed mRNAs between two samples of a patient taken in different contexts (e.g. cancer vs non cancer), which we termed responsive transcripts (RTs). MethodsWe propose a new N-of-1-pathways method, k-Means Enrichment (kMEn), that detects bidirectionally responsive pathways, despite background noise, using a pair of transcriptomes from a single patient. kMEn identifies transcripts responsive to the stimulus through k-means clustering and then tests for an over-representation of the responsive genes within each pathway. The pathways identified by kMEn are mechanistically interpretable pathways significantly responding to a stimulus. ResultsIn ∼9000 simulations varying six parameters, superior performance of kMEn over previous single-subject methods is evident by: (i) improved precision-recall at various levels of bidirectional response and (ii) lower rates of false positives (1-specificity) when more than 10% of genes in the genome are differentially expressed (background noise). In a clinical proof-of-concept, personal treatment-specific pathways identified by kMEn correlate with therapeutic response (p-value<0.01). ConclusionThrough improved single-subject transcriptome dynamics of bidirectionally-regulated signals, kMEn provides a novel approach to identify mechanism-level biomarkers.

83 BONE MORPHOGENETIC PROTEIN SIGNALING DURING INTERACTION OF THE BOVINE EMBRYO WITH OVIDUCTAL EPITHELIAL CELLS IN VITRO

In previous studies, we have demonstrated that different signalling components of bone morphogenetic proteins (BMP) are expressed in an anatomically and temporally regulated fashion in the bovine oviduct. However, a local response of this signalling to the embryo presence has not been elucidated yet. The aim of the present study was to evaluate whether the interaction of the embryo with the oviduct can induce changes in the gene expression of BMP signalling components. For this purpose, we used an in vitro co-culture system of a bovine oviducal epithelial cell (BOEC) monolayer with pre-implantation embryos in 2 developmental time points: before and during the main phase of embryonic genome activation (EGA). Isthmus epithelial cells from post-ovulatory stage oviducts (Day 2–4) were cultured in 500 μL of SOF + 10% FCS in 4-well plates at 38.5°C, 5% CO2, 5% O2, and 90% N2. On Day 6 of culture, medium was replaced with SOF + 5% FCS, and 24 h later BOEC monolayer was cultured in the absence or presence of in vitro-produced embryos from 2- to 8-cell stage [G1 BOEC; 33–54 h post-insemination (hpi)] or from 8- to 16-cell stage (G2 BOEC; 54–98 hpi) in the same conditions. In both groups, a polyester mesh was used to define a local co-culture area, and 30 embryos per well were placed in a 6 × 5 grid over the monolayer. In addition, as control groups, embryos in both developmental stages were cultured either in SOF + 5% FCS (G1 FCS and G2 FCS) or in SOF + 3 mg mL−1 BSA (G1 BSA and G2 BSA). At 54 hpi (G1 BOEC/BSA/FCS) or 98 hpi (G2 BOEC/BSA/FCS), embryos that reached 8- or 16-cell stage, respectively, were transferred to SOF + BSA and cultured until Day 9. The mRNA expression levels of 3 BMP receptors (BMPRIA/IB/II), 2 signalling proteins (SMAD1/5), 1 inhibitor (SMAD6), and 1 target gene (ID2) were analysed by qPCR in 5 samples of BOEC cultured with or without embryos before or during EGA, and in 3 pools of 10 embryos at 8 (54 hpi), 16 (98 hpi), and blastocyst stage (Day 7–8) from all groups. Genes H2A.Z and ACTG1 were used as housekeeping genes, and statistical differences were assessed by ANOVA. The presence of the embryo, irrespective the stage, significantly reduced the expression levels of BMPRIB, BMPRII, SMAD1, SMAD6, and ID2 in BOEC. Embryos that interacted with BOEC before EGA (G1 BOEC) showed a significant increase in the relative abundance of SMAD1 at the 8-cell stage compared with controls. Moreover, embryos that interacted with BOEC during EGA (G2 BOEC) showed a significant increase in the relative abundance of BMPRIB, BMPRII, and ID2 at the 16-cell stage when compared with controls. However, no differences were observed in the mRNA expression levels of BMP signalling components in the blastocysts between groups. In conclusion, local embryo-oviduct interaction in vitro induces changes in the transcriptional levels of BMP signalling, causing a bidirectional response that reduces the expression levels of this signalling in the oviducal cells while increases them in the embryo at early stages. This suggests that BMP signalling pathway could be involved in an early cross-talk between the bovine embryo and the oviduct during first stages of development.

A reference library of thermal infrared mineral reflectance spectra for the HyLogger-3 drill core logging system

ABSTRACTA new reference library of thermal infrared spectral reflectance measurements of the major rock-forming and alteration minerals has been compiled to support and enhance analysis of data acquired using the CSIRO HyLogger-3 drill-core logging system. The HyLogger-3 is a robotic system that acquires large volumes of bidirectional reflectance spectra from diamond drill core within the wavelength range of visible light, the near infrared and shortwave infrared (400–2500 nm) as well as the thermal infrared from 6000 to 14 000 nm. The library samples were selected as single pure solid mineral crystals or monomineralic hand samples judged to have a similar bidirectional spectral response to that of typical diamond drill cores. Furthermore, a large number of individual mineral samples were chosen to cover the various natural spectral variations within single mineral groups such as, for example, a range of solid solutions of plagioclase. Owing to the bidirectional measurement geometry of the HyLogger-3, spectral variations caused by crystal orientation effects are also expected. Accordingly, reflectance measurements were made for multiple surfaces/facets of each sample, and also for orthogonal orientations of the plane of incidence illumination for each facet measured. All measured spectra were compared with existing library spectra or with spectra measured from validated samples to judge whether the mineral samples could be regarded as pure and, where possible, their chemical composition and mineralogy were validated by X-ray fluorescence and X-ray diffraction. For quality control, all such relevant metadata, including macroscopic descriptions of each sample, were collated in an associated database. In total, the spectral library contains more than 2000 spectra, from 562 specimens, representing 130 mineral groups. This library focuses on the most common rock-forming minerals of relevance to metalliferous exploration and mining, with a few limitations resulting from availability of suitable samples, which will be addressed as new samples become available. Comparisons with emission spectra from existing spectral libraries show good agreement, indicating that this spectral library will also be useful in the remote sensing domain.

Bi-Directional Pseudo-Acceleration Response Spectra

In seismic design, excitations are usually considered separately in two perpendicular directions of structures. In fact, the two components of ground motions occur simultaneously. This paper clarifies the effects of bi-directional excitations on structures and proposes the response spectra called “bi-directional pseudo-acceleration response spectra”. A simplified analytical model of a two-degree-of-freedom system was employed. The effect of directivity of ground motions was taken into account by applying strong motion records in all directions. The analytical results were presented in the form of the acceleration ratio response spectrum defined as the bi-directional pseudo-acceleration response spectrum normalized by a pseudo-acceleration response spectrum.