Intrinsic Compression Research Articles

Compressive Optic Neuropathy; Clinical Findings, Etiopathogenesis, Diagnosis and Treatment

Compressive optic neuropathy (COM) is a type of optic neuropathy characterized by slow and progressive vision loss, usually unilateral, resulting from the intrinsic or extrinsic compression of any part of the optic nerve. This condition may develop because of infectious, inflammatory, vascular, traumatic, and neoplastic factors. In the early diagnosis of the disease, making differential diagnoses correctly; evaluating additional hematological, biochemical, and inflammatory blood parameters; and applying orbital and neuroimaging methods when necessary are critical. In addition, coordination with other branches of science in diagnosing and treating CON is an important step in terms of disease management and the improvement of visual prognosis.

A Compact GaN Power Amplifier Module for New Generation Cellular Basestations

This paper presents a compact class-AB Power Amplifier Module (PAM) designed for new generation massive Multiple Input Multiple Output (MiMo) cellular base stations. The module is designed at the center frequency of 3.5GHz targeting Long Term Evolution (LTE) and 5G New Radio (NR) bands. The module is a hybrid design that incorporates a Gallium Nitride (GaN) High Mobility-Electron Transistor (HEMT) die, discrete components-based input, and output matching networks. The entire design is realized on an 8.5 x 5.2 mm, 2-layer Rogers4003C substrate. The module is assembled on a PCB as an open-top for post-characterization tuning. The small signal and large signal measurements are in quite good agreement. The measurement results show that the amplifier is unconditionally stable, the input return loss is 12.2 dB, the output return loss is 7.7 dB, and the small signal gain is 13.4 dB. The saturated output power is 33.3 dBm with a Power Added Efficiency of 20.1%. The small signal gain drops to 11.2 dB at around 22 dBm of input power due to GaN technology’s intrinsic soft compression characteristics.

A new framework for evaluating the virgin compression curves of reconstituted clays at different initial water contents

The influence of initial water content on the virgin compression of reconstituted clays is a topic of great importance. This study introduces a novel perspective based on the concept of intrinsic compression. It is demonstrated that the virgin compression curves of the reconstituted clays are similar in shape to the intrinsic compression line and can be obtained through vertical shifting and stretching. Building upon this concept, the intrinsic compression line is further extended to the compression curve cluster, enabling a direct evaluation of the influence of initial water content. The validity of the compression curve cluster is verified using independent data from the literature as well as data collected by our research team. In addition, a comparison with other relevant theories further underscores the superiority of the proposed framework.

Remote Intelligent Medical Monitoring Data Transmission Network Optimization based on Deep Learning

A hospital operating status evaluation data analysis system was established based on the autoencoder's network. The Gibbs sampling method is used to obtain the approximate distribution of RBM. In addition, the Autoencoder neural network can also select feature dimensions that can better characterize the characteristics of financial operation data from a large amount of financial operation data. Deep learning methods are used to study the redundant information elimination method and the generation mechanism of multi-source heterogeneity in multi-source heterogeneous networks. The principle of intrinsic compression is used to reduce the dimensionality of the redundancy in the network and obtain the compression redundancy objective function. This article sets thresholds for information classification on the Internet. The approach was tested using financial data from a medical institution. Use smart encoders to extract 17 financial indicators from financial data that can be used for modeling. The evaluation results are used as the output vector of the model. Comparative experiments show that the AUC value and accuracy of the method proposed in this article can be improved by 0.84 and 83.33% compared with the AUC value of shallow logistic regression and BP neural network. This algorithm has apparent improvements.

Intrinsic compressibility of laterites and lateritic soils

Laterites and lateritic soils, prevalent in tropical and subtropical climates, have growing applications in earthwork construction. They usually present unique compression properties compared to conventional clays. Therefore, a thorough understanding of their intrinsic compressibility is crucial. This paper reports on modified oedometer tests conducted on reconstituted samples of four distinct laterites and lateritic soils with varying initial water contents. In addition, scanning electron microscopy (SEM) was utilized to identify the microstructural features to reveal the mechanisms of intrinsic compression. The results demonstrate that intrinsic compression curves of reconstituted laterites and lateritic soils align with Burland’s normalization framework. However, they exhibit a higher void ratio at an effective vertical stress of 100 kPa ( e* 100) and a lower compression index ( C* c) compared to traditional clays; therefore, existing formulas for calculating e* 100 and C* c are inapplicable to laterites and lateritic soils. The SEM analysis revealed that sesquioxide interacts with soil minerals, resulting in a porous structure and robust inter-unit cementation. This unique microstructure contributes to the observed intrinsic constants of compressibility, e* 100 and C* c. Based on the experimental observations, new empirical equations are introduced to evaluate e* 100 and C* c in laterites and lateritic soils. The experimental results elucidate the role of sesquioxide in inherent compressibility and improve our understanding of compressibility characteristics that are unique to laterites and lateritic soils.

Hourglass Constrictive Neuropathy: A Likely Underdiagnosed Condition with Characteristic Imaging Features.

Teaching point: Hourglass-like constrictive neuropathy should be considered in patients with unexplained peripheral neuropathy symptoms, as imaging may show nerve constriction without evidence of intrinsic or extrinsic compression.

Uncovering acoustic signatures of pore formation in laser powder bed fusion

We present a machine learning workflow to discover signatures in acoustic measurements that can be utilized to create a low-dimensional model to accurately predict the location of keyhole pores formed during additive manufacturing processes. Acoustic measurements were sampled at 100 kHz during single-layer laser powder bed fusion (LPBF) experiments, and spatio-temporal registration of pore locations was obtained from post-build radiography. Power spectral density (PSD) estimates of the acoustic data were then decomposed using non-negative matrix factorization with custom varvec{k}-means clustering (NMFvarvec{k}) to learn the underlying spectral patterns associated with pore formation. NMFvarvec{k} returned a library of basis signals and matching coefficients to blindly construct a feature space based on the PSD estimates in an optimized fashion. Moreover, the NMFvarvec{k} decomposition led to the development of computationally inexpensive machine learning models which are capable of quickly and accurately identifying pore formation with classification accuracy of supervised and unsupervised label learning greater than 95% and 90%, respectively. The intrinsic data compression of NMFk, the relatively light computational cost of the machine learning workflow, and the high classification accuracy makes the proposed workflow an attractive candidate for edge computing toward in-situ keyhole pore prediction in LPBF.

Compressive Optic Neuropathy (CON) Secondary to Inflammatory Polyp Mimicking Lymphoma: A Rare Manifestation

Introduction: Compressive optic neuropathy (CON) is the impairment of optic nerve function by space-occupying lesions that mechanically compress the optic nerve or optic tract. CON can arise from either intrinsic or extrinsic compression, and determining the underlying cause is important to approach the correct management. The objective of this case report is to present a rare case of CON secondary to an inflammatory polyp that mimicking lymphoma. Case Presentation: A 68-year-old male patient came to the neuro-ophthalmology clinic with a chief complaint of blurry vision in his left eye since three months ago that was getting worse until he lost his vision accompanied by drooping of the upper left eyelid. He also felt pain in his left eye, nausea, vomiting, and headache. Visual acuity of the right eye was 5/5 and the left eye had no light perception. Ocular motility of the left eye was restricted in all gaze. The pupil was 6 mm with no light reflex, and edema in the optic nerve head in the left eye was found from the posterior segment. The patient's MRI showed soft tissue thickening on the left orbital apex – left optic canal – left anterior cavernous sinus and enlargement of left medial rectus muscle with encasement of the left optic nerve, and from post-contrast showed contrast enhancement that suggested a lymphoma. He was diagnosed with CON secondary to lymphoma and was given Methylprednisolone 32 mg three times a day orally. Conclusions: Several differential diagnoses resemble the findings of CON secondary to inflammatory polyp. Some diagnostic examination must be done to exclude the other diagnosis to give a proper treatment for the patient.

Segmental extraneural lipomatosis of the superficial peroneal nerve: illustrative case.

Adipose lesions of nerve are rare tumors that can cause nerve symptoms from either intrinsic or extrinsic compression. The authors present a case of a patient with a 10-year history of progressive, persistent leg pain and dorsal foot paresthesias/dysesthesias. Imaging revealed several nondistinct nodules of indeterminate significance along the course of the superficial peroneal nerve (SPN). Surgery demonstrated six distinct extraneural lipomas studded on a 10-cm segment of the main SPN and one of its muscular branches in the midleg. The lesions were adherent to the SPN, without an easy dissection plane; therefore, a neurectomy was performed. Histology revealed the nerve was associated with multiple extraneural lipomas with focal evidence of prior trauma. At 4 months postoperatively, the patient's pain had resolved completely, and she was able to resume normal physical activities. The current classification of adipose lesions of nerve includes intraneural and extraneural lipomas and lipomatosis of nerve (fibrolipomatous hamartoma). The unique features of the present case include the discrete and segmental nature of the extraneural lipomas adherent to the nerve. Its etiology is unknown, and the histology would be suggestive of either a traumatic or a degenerative process.

Compressive Behavior of Reconstituted Soils at High Initial Water Content: Case Study on South-Western Region Of Bangladesh

This study illustrates the experimental investigation of the effect of high initial water content on the compression behavior of reconstituted soil. For this attempt, disturbed soil samples were collected from two selected locations of the KUET campus, Khulna, Bangladesh. The reconstituted soils were prepared in the laboratory at different initial water content, ranging from 0.7 to 1.2 times their corresponding liquid limit. The main focus of this study was to investigate the compression behavior of reconstituted clays using oedometer tests. This work was complementary to the intrinsic compression line concept proposed by Burland (1990). In the laboratory, ASTM methods were followed to measure the initial properties of soils. Here, it can be observed that e - logσv compression curves show an inverse "S" shape as a result of resisting deformation due to pressure. Moreover, some important correlations were developed based on the initial void ratio and the void ratio at the liquid Limit e0/eL . It has been observed that the void index is a dominating parameter to normalize the squeezability characteristics at different initial water contents in the plastic post-yield regime. A non-unique relationship is obtained for different soils to express the intrinsic compression line concept. However, there is a proportional relationship between intrinsic compressibility and initial water contents or liquid limits. Journal of Engineering Science 14(1), 2023, 1-9

Effects of organic content on sewage sludge compression behaviour

Five sewage sludge specimens with different organic contents were prepared by mixing mass ratios of 0, 5, 10, 20 and 40% dry soil powder into raw sewage sludge. The addition of dry soil powder can reduce the organic content of sewage sludge without significantly changing its particle composition. Oedometer tests were conducted, starting from a small effective vertical stress [Formula: see text]. It is observed that the [Formula: see text] compression curves show an inverse ‘S’ shape due to suction pressure resisting deformation. The suction pressure decreases exponentially with the organic content, a regression equation for which is provided. Burland’s concept of the intrinsic compression line (ICL) is adopted for correlating the compression curves of sludge with various organic contents. It is found that the ICL with a high organic content lies above the low one – that is, the higher the organic content, the greater the void index. In addition, the shape of the ICL for organic sludges is an inverse S rather than slightly concave upwards for inorganic reconstituted clays. An average ICL is provided to normalise the compression curves of sludges with different organic contents. The intrinsic compression parameters [Formula: see text] and [Formula: see text] can be correlated with the organic content, which increase linearly with the organic content, and the regression equations for them are provided.

Structure and equation of state of Bi2Sr2Can−1CunO2n+4+δ from x-ray diffraction to megabar pressures

Pressure is a unique tuning parameter for probing the properties of materials, and it has been particularly useful for studies of electronic materials such as high-temperature cuprate superconductors. Here we report the effects of quasihydrostatic compression produced by a neon pressure medium on the structures of bismuth-based high-Tc cuprate superconductors with the nominal composition Bi2Sr2Can−1CunO2n+4+δ (n=1,2,3) up to 155 GPa. The structures of all three compositions obtained by synchrotron x-ray diffraction can be described as pseudotetragonal over the entire pressure range studied. We show that previously reported pressure-induced distortions and structural changes arise from the large strains that can be induced in these layered materials by nonhydrostatic stresses. The pressure-volume equations of state (EOS) measured under these quasihydrostatic conditions cannot be fit to single phenomenological formulation over the pressure ranges studied, starting below 20 GPa. This intrinsic anomalous compression as well as the sensitivity of Bi2Sr2Can−1CunO2n+4+δ to deviatoric stresses provide explanations for the numerous inconsistencies in reported EOS parameters for these materials. We conclude that the anomalous compressional behavior of all three compositions is a manifestation of the changes in electronic properties that are also responsible for the remarkable nonmonotonic dependence of Tc with pressure, including the increase in Tc at the highest pressures studied so far for each. Transport and spectroscopic measurements up to megabar pressures are needed to fully characterize these cuprates and explore higher possible critical temperatures in these materials.1 MoreReceived 15 December 2022Accepted 5 May 2023DOI:https://doi.org/10.1103/PhysRevMaterials.7.064803©2023 American Physical SocietyPhysics Subject Headings (PhySH)Research AreasEquations of stateHigh-pressure studiesPhysical SystemsCupratesTechniquesX-ray diffractionCondensed Matter, Materials & Applied Physics

Equivalent Compression Curve for Clay–Sand Mixtures Using Equivalent Void-Ratio Concept

Clay–sand mixtures are deposited worldwide, such as naturally sedimentary soils and dredged clays in human activities. These mixtures usually have a fine fraction above the transitional fine content, and the compressibility is dominated by clay matrix and affected by sand fraction. In this paper, an explicit equivalent compression curve is proposed for clay–sand mixtures. This is done by directly incorporating the equivalent void ratio into the intrinsic compression model of the clay matrix. The roles of initial and evolving soil structure developed during the compression process are described by a structural variable, which can be directly computed from the experimental data. Experimental data compiled from various literature are used for evaluating the accuracy of the suggested model. They indicate that the proposed relationship of stress versus equivalent void ratio is simple yet effective to evaluate the compressibility of clay–sand mixtures with a wide spectrum of sand fraction. The model is also practically useful for estimating the compressibility of other gap-graded soils, such as clay–gravel mixtures. The proposed stress versus equivalent void-ratio equation is an elementary function and can be readily implemented into general elastoplastic models.

The behaviour of a low- to medium-density chalk under a wide range of pressure conditions

Experiments are described which provided the basis for advanced numerical modelling of large-scale axial and lateral pile tests undertaken chalk to assist the design of offshore wind and other projects in northern Europe. The research explored the mechanical behaviour of chalk from a UK research site under effective cell pressures up to 12.8 MPa. When sheared from low confining pressures the chalk’s interparticle bonds contribute a large proportion of the peak deviator stresses available to specimens that crack, bifurcate and dilate markedly after failing at relatively small strains. Progressively more ductile behaviour is seen as pressures are raised, with failures being delayed until increasingly large strains and stable critical states are attained. Loading invokes very stiff responses within the chalk’s (Y1) linear elastic limits and behaviour remains stiff, although non-linear, up to large-scale (Y3) yield points. Near-elliptical Y1 and Y3 yield loci can be defined in q-p′ stress space and a critical state v-p′ curve is identified. The chalk’s initially bonded, high porosity, structure is explored by normalising the shearing and compression state paths with reference to both critical state and intrinsic compression lines. The results have important implications for pile test analysis and practical design in this challenging geomaterial.

929: ENDOBRONCHIAL METASTASIS FROM OSTEOSARCOMA: TREATMENT WITH CRYOTHERAPY AND ARGON PLASMA COAGULATION

Introduction: Osteosarcoma is the most common primary malignant tumor of the bone. Pulmonary metastasis is frequently seen as a relapse in approximately 80% of patients; however, endobronchial metastasis is very rare. We present a case of endobronchial osteosarcoma in a young man. Description: A 20-year-old male non-smoker with a history of treatment-refractory metastatic osteosarcoma presented with shortness of breath, dry cough, and episodes of hemoptysis for a few days. On presentation, vital signs were significant for tachycardia (HR 113/min) and tachypnea (RR 24/min). Chest CT scan showed no pulmonary embolism but revealed bilateral pulmonary and pleural metastases with severe narrowing of the right upper lobe pulmonary artery segmental branches secondary to metastases. At fiberoptic bronchoscopy, there was complete obstruction of the right upper lobe apical and posterior segments by a dark red vascular appearing tumor. Cryotherapy was performed to destroy abnormal tissue, along with balloon occlusion. Coagulation using an Argon Plasma Coagulation (APC) was performed in the lung. Post-treatment findings showed improved lumen size. The patient tolerated the procedure well and had remarkable improvement in symptoms. Biopsy of the endobronchial tumor showed metastatic sarcoma, similar to the patient’s prior high-grade pleomorphic sarcoma. Discussion: Airway obstruction may be extrinsic, intrinsic, or mixed; fixed or dynamic; and benign or malignant. It may present with a variety of symptoms ranging from mild shortness of breath to respiratory failure. There are few published case reports of endobronchial obstruction secondary to osteosarcoma. Bronchoscopy (either rigid or flexible) is always necessary for assessing airway obstruction. Dilation is immediately effective for intrinsic and extrinsic compression, but results are typically not sustained. Cryotherapy relies on repeated freeze-thaw cycles using extreme cold (below –40°C) to destroy tissue and tumor and can be used via both rigid and flexible bronchoscopes. APC is a mode of noncontact electrocoagulation that is increasingly used as an alternative to contact electrocautery and noncontact laser therapy. Often, the best therapeutic approach appears to include a combination of several treatment approaches as demonstrated in our patient.

Multiband dual- and cross-LFM waveform generation using a dual-drive Mach–Zehnder​ modulator

Linear frequency modulation (LFM) signals are widely used in modern radar systems owing to their intrinsic pulse compression capability but are restricted due to a limited range-Doppler resolution. On the other hand, dual- or cross-LFM signals have complementary LFM waveforms at the same time instant that reduces the range-Doppler coupling and thus improving range-Doppler resolution. We propose a simple microwave-photonic-based approach to generate multiband dual- and cross-LFM waveforms using only a single dual-drive Mach–Zehnder modulator (DDMZM). A theoretical analysis is carried out, which is modeled and verified through experiments. Dual- and cross-LFM waveforms at a carrier frequency of 6 GHz and 18 GHz with a bandwidth of 2 GHz is generated by controlling the DC and RF bias of the DDMZM. The tunability of the carrier frequency from 3 GHz to 9 GHz is also verified. A range resolution of 6.3 cm for dual- and cross-LFM waveforms, is obtained with a time-bandwidth-product (TBWP) of 20,000. The proposed technique is a promising solution for dual- and cross-LFM waveform generation in two-band multipurpose radar systems.

Geotechnical characterization of deep Shanghai clays

To date, investigations of soils in Shanghai have mainly focused on upper clays, namely, Layer 2–6, generally within 30–40 m depth. Knowledge of the deep clays of Layer 8 and 10, at depths of approximately 50 m and 100 m, respectively, is very limited. In this study, the detailed geotechnical properties of the deep Shanghai clays of these two layers were investigated through a series of field and laboratory tests. Physical property tests showed that both clays can be classified as low-plasticity silty clay. For the first time in Shanghai, high-quality intact clay samples were retrieved from the deep soil using a double-tube rotary sampler. High-pressure oedometer tests and consolidated undrained (CU) triaxial tests were conducted to evaluate the compressibility and shear strength of intact samples. The oedometer tests indicate that Layer 8 is an overconsolidated clay with an overconsolidation ratio (OCR) of 2–3, and Layer 10 is a normally consolidated clay with a light degree of structure. CU triaxial tests further confirmed the above findings. The compressibility of the Layer 8 clay is lower, and its undrained shear strength and effective friction angle are larger than those of Layer 10, with the latter being deeper. The sensitivity framework, based on Burland's intrinsic compression line (ICL) and sedimentary compression line (SCL), can be used to characterize the overconsolidation/structure nature of the deep Shanghai clays. The strain energy method was found to be more suitable than the Casagrande method for determining the preconsolidation pressure of the deep Shanghai clays.

Experiment study on normalized compression behaviour of marine diatomaceous soil considering microstructure of biogenic silica

There are many sites in the world where diatom microfossils have been detected, but very little is known about their effect on sediment geotechnical properties. Diatomaceous soils (herein called “biogenic silica soils”) are usually composed by a mix of sand, fine-grained clay and diatom (and, or radiolarian). This paper presents an experimental investigation on the compression behaviour of biogenic silica-kaolin (BSi-K) clay mixtures and natural marine diatomaceous soils. The results show that the BSi composition dominates the compression when the BSi content is higher than 50%. The microstructure of biogenic silica frustules is first characterized and a skeletal void volume model (BSi-SVV model) is proposed. By using this model, the addition water in biogenic silica frustules can be quantitatively evaluated, which is up to 92.6% as the BSi content is 78%. It can be explained as the cause of high natural water content and low plasticity of diatomaceous soils. By introducing the effective void ratio, the compression curves can be normalized; furthermore, a new intrinsic compression line (BSi-ICL) suitable for BSi-K clay mixtures is developed based on the intrinsic compressibility concept of Burland (1990). It is considered as an extension of Burland's ICL. Finally, the effect of initial water content on the normalized compression behaviour is investigated. The findings in this study can provide a deeper insight into the geotechnical properties of marine diatomaceous soils.

Effects of initial water content on compression behaviour of municipal sewage sludge

To investigate effects of initial water content on compression behaviour of municipal sewage sludge and clarify its intrinsic compression characteristics. Oedometer tests were conducted on sludge with various initial water content of 0·13–1·48 times the liquid limit. It is observed that the sludge is organic high liquid limit silt, whose e–log σ′vcompression curves are inverse ‘S’ shape due to organic floc structure of sludge potentially. When the effective vertical stress σ′v > 100 kPa, a clear gap of compression curves of various initial water content still exists, different from Burland's viewpoint that compression curves tend to be consistent. Burland's concept of intrinsic compression line (ICL) is adopted for correlating compression curves of sludge well, and an ICL of the sludge is derived. The ICL of sludge is below ones reported by Hong and Burland when σ′v < 100 kPa, due to the difference in initial water content. A generalised void index is tentatively proposed by introducing generalised intrinsic parameters e*y1and e*y2, which may be related to the loading history of the soil and the maximum load that the soil may bear in future engineering, respectively.

Test of Consolidation-Collapse Properties of the Black Soil of Northeast China Based on Burland Model

Organic matter is widely distributed in soils, which has remarkably influenced geotechnical engineering. The difference of the soil's structure, chemical constitution, and organic content leads to the distinction of mechanical property. The current research concentrates on the mechanical property of peaty soil and peat, and research on organic soil is rare. Several slope engineering issues show that the rainwater contact with the organic soil layer causes soil landslide, and the mechanism of landslide is that organic matter softens when it soaks the water under the vertical press. Studying the mechanical influence of organic soil with change in moisture content is meaningful because the moisture content of organic soil is much less than that of peat. This study mainly has the following content. The one-dimensional compression test with a variation of organic matter (F) and water (W) is selected to reveal the compression characteristics of organic soil. According to the analysis of the research consequence, the collapsibility with different organic contents and the same void ratio was further analyzed, and the research revealed the influence factor by analyzing the process of the collapse. Burland intrinsic compression theory, which reveals the soil's structure by analyzing the difference of undisturbed soil and remolded soil, was suitable for the initial moisture content of 1.5 to 2 times the liquid limit but not for organic soil with a moisture content lower than the liquid limit. Therefore, a modified model was provided to widen the range of liquid limit and present the phenomenon of collapse, and good prediction outcome can be obtained based on the linear-regression analysis model and the modified model. A black soil collapsibility model was established based on the experimental results, and it has good prediction outcome.