Tight Space Research Articles

Designing Human-Robot Coexistence Space

When the human-robot interactions become ubiquitous, the environment surrounding these interactions will have significant impact on the safety and comfort of the human and the effectiveness and efficiency of the robot. Although most robots are designed to work in the spaces created for humans, many environments, such as living rooms and offices, can be and should be redesigned to enhance and improve human-robot collaboration and interactions. This letter uses autonomous wheelchair as an example and investigates the computational design in the human-robot coexistence spaces. Given the room size and the objects O in the room, the proposed framework computes the optimal layouts of O that satisfy both human preferences and navigation constraints of the wheelchair. The key enabling technique is a motion planner that can efficiently evaluate hundreds of similar motion planning problems. Our implementation shows that the proposed framework can produce a design around three to five minutes on average comparing to 10 to 20 minutes without the proposed motion planner. Our results also show that the proposed method produces reasonable designs even for tight spaces and for users with different preferences.

COVID-Safe Spatial Occupancy Monitoring Using OFDM-Based Features and Passive WiFi Samples

During the COVID-19 pandemic, authorities have been asking for social distancing to prevent transmission of the virus. However, enforcing such distancing has been challenging in tight spaces such as elevators and unmonitored commercial settings such as offices. This article addresses this gap by proposing a low-cost and non-intrusive method for monitoring social distancing within a given space, using Channel State Information (CSI) from passive WiFi sensing. By exploiting the frequency selective behavior of CSI with a Support Vector Machine (SVM) classifier, we achieve an improvement in accuracy over existing crowd counting works. Our system counts the number of occupants with a 93% accuracy rate in an elevator setting and predicts whether the COVID-Safe limit is breached with a 97% accuracy rate. We also demonstrate the occupant counting capability of the system in a commercial office setting, achieving 97% accuracy. Our proposed occupancy monitoring outperforms existing methods by at least 7%. Overall, the proposed framework is inexpensive, requiring only one device that passively collects data and a lightweight supervised learning algorithm for prediction. Our lightweight model and accuracy improvements are necessary contributions for WiFi-based counting to be suitable for COVID-specific applications.

PD41-06 EFFECT OF PELVICALYCEAL FLUID VOLUME ON TEMPERATURE ELEVATION AND THERMAL DOSE DURING LASER LITHOTRIPSY

You have accessJournal of UrologySurgical Technology & Simulation: Instrumentation & Technology II (PD41)1 Sep 2021PD41-06 EFFECT OF PELVICALYCEAL FLUID VOLUME ON TEMPERATURE ELEVATION AND THERMAL DOSE DURING LASER LITHOTRIPSY Nikta R. Khajeh, Timothy L. Hall, Khurshid R. Ghani, and William W. Roberts Nikta R. KhajehNikta R. Khajeh More articles by this author , Timothy L. HallTimothy L. Hall More articles by this author , Khurshid R. GhaniKhurshid R. Ghani More articles by this author , and William W. RobertsWilliam W. Roberts More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002051.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: While high-power holmium lasers facilitate successful ureteroscopic treatment of larger and more complex stones, they can also substantially elevate fluid temperatures in the ureter and collecting system potentially causing thermal injury of the adjacent tissue. Fluid volume is an important factor when assessing temperature elevation. The aim of this study was to investigate temperature elevation and thermal dose from laser lithotripsy in model calyces/pelvises spanning a clinically relevant range of fluid volumes. METHODS: Glass bulbs of volumes 0.5, 2.8, 4.0, 7.0, 21.0, and 60.8 mL served as calyx/pelvis models. A single bulb was submerged in a tank of 37˚C deionized (DI) water to simulate core body temperature. A 230 µm core laser fiber extending 5 mm from the tip of a LithoVue ureteroscope was positioned in the center of the model. Irrigation settings of 0, 8, 15, and 40 ml/min with room temperature DI water were used while a P120 Ho:YAG laser was activated for 60 seconds at 40W (0.5 J x 80 Hz, SP). Temperature was measured every second by a thermocouple affixed 5 mm from the tip of the ureteroscope. 5 trials were run under each parameter. Thermal dose was calculated from the temperature curves using the Dewey and Sapareto t43 methodology with t43=120 equivalent minutes accepted as the threshold for thermal injury. RESULTS: The rate of temperature elevation and thermal dose from laser activation were inversely proportional to the volume of fluid in each model and the irrigation rate. The time to threshold for thermal injury was only 3 seconds for the smallest model (0.5 ml) without irrigation, while it was never reached in the largest model (60.8 mL), regardless of irrigation rate (table). 40 ml/min irrigation maintained safe temperatures below the threshold for injury in all models (figure). CONCLUSIONS: Clinicians should be mindful when using high power laser settings in confined calyxes, or tight spaces as heating of small volume fluid to dangerous levels can occur quickly. Source of Funding: Research grant from Boston Scientific © 2021 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 206Issue Supplement 3September 2021Page: e682-e683 Advertisement Copyright & Permissions© 2021 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nikta R. Khajeh More articles by this author Timothy L. Hall More articles by this author Khurshid R. Ghani More articles by this author William W. Roberts More articles by this author Expand All Advertisement Loading ...

Robotic Sorting Systems: Performance Estimation and Operating Policies Analysis

Many distribution centers use expensive, conveyor-based sorting systems that require large buildings to house them. In areas with tight space, robotic sorting systems offer a new type of solution to sort parcels by destination. Such systems are highly flexible in throughput capacity and are now gradually being introduced, particularly in express companies. This paper studies robotic sorting system with two layouts. The first layout has two tiers: robots drive on the top tier and sort parcels by destination on spiral conveyors connected to roll containers at the lower tier. The second layout has a single tier with input and output points located at the perimeter, connected by robots. For each layout, we consider both the shortest path topology via dual-lane aisles and the detour path topology via single-lane aisles. We build closed queueing networks for performance estimation, design an iterative procedure to investigate robot congestion in the two-tier layout, and use a traffic flow function to estimate robot congestion in the single-tier layout. Random, closest, dedicated, and shortest-queue robot-to-loading-station assignment rules are examined. We validate analytical models by both simulation and a real case of Deppon Express and analyze the optimal system size and operating policies for throughput capacity and operating cost. The results show that the system throughput capacity is significantly affected by robot congestion in the single-tier layout with the detour path topology, but it is only slightly affected in the other systems. A square layout fits the shortest path and a rectangular layout fits the detour path. Both the random assignment rule and the shortest-queue assignment rule are superior for a large number of robots, whereas the dedicated assignment rule is superior for a small number of robots. We apply these insights at Deppon Express for different allocations in peak and off-peak hours. Our analysis shows that a robotic sorting system typically has lower overall annual cost than a traditional cross-belt sorting system when the required throughput capacity is not too large.

Design Optimization & Analysis of a Soft Crawling Robot

Soft crawling robots (SCRs) are the kind of robots that use soft and flexible material for motion. These soft robots capable to sustain huge distortions with vast degree-of-freedom which makes them more suitable to be employed in unstructured location compared to the conventional rigid robots. Unlike soft robotics, the conventional rigid robots are capable to be employed in situations where precision is required. However, soft robots are preferable in tight spaces such as in medical surgery and earthquake search and rescue operations due to its flexibility and adaptability capability. In this research, two types of soft robots were design using i.e.: (a) inchworm design and (b) quadrupedal design. The similarities between the inchworm and quadrupedal design are both use pressure input for motion. The SCRs also bend by using the expansion of chambers at their body. Both designs have the same length fixed at 86mm, but with different topology. The design optimization for maximum bending motion with respect to input pressure were evaluated using Finite Element Method (FEM) via Abaqus software, where the results shows that the highest bending was observed for the inchworm design. The maximum bending value (extension) of 130.4 mm was obtained with the optimized parameters set at 4mm base thickness, 5mm chamber gap, and 2mm width for the air chamber, respectively.

Fracturing Technologies for Horizontal Wells in the Second-Class Shale Oil Reservoirs of the Lower Sweet Spot Areas in Jimusar

Technical research was carried out to enhance fracture control in fracturing with tight spacing and boost longitudinal production by cross layer fracturing in thin interbeddings. The research aims to address the difficult enhancement of horizontal well production induced by low fluidity and limited fracture height in beddings of the shale oil reservoirs in Jimusaer, Junggar Basin, and improve the production in the second-class shale oil reservoirs of the lower sweet spot areas in this region. The technique of fracturing with tight spacing was studied, with the average inter-cluster spacing reduced to 13.6 m, greatly strengthening the fracture control in shale oil reservoirs. The displacement and gel amount during vertical well fracturing were increased, and the feasibility of cross layer fracturing in the second-class reservoirs of the lower sweet spot areas was verified. As a result, the key technologies of cross layer fracturing, featured by large displacement (12–14 m3/min) in horizontal wells, multi-slug pumping of gel and slick water, proppant integrating medium and small particle sizes, and large sand addition (2.7 m3/m), were developed to provide strong support against the turning fractures in beddings.The annual cumulative oil production of the horizontal test wells in the second-class reservoirs achieved 9 183 t, more than three times that of previous horizontal wells.The field test demonstrates that the technologies can enlarge the fracturing volume in horizontal wells.The research results show that the cross layer fracturing with tight spacing for horizontal wells can solve the production problem of multiple thin oil layers in the second-class reservoirs and provide a new technical approach for the fracturing production of horizontal wells in such reservoirs.

A practical gas permeability equation for tight and ultra-tight rocks

Gas rarefaction phenomenon during gas flows in tight pore spaces makes the gas permeability of tight and ultra-tight rocks higher than the intrinsic permeability. Gas permeability equations in the literature usually assume a pre-defined pore morphology (or geometry) which may not reflect the real pore structure of rocks. This study aims to develop a practical gas permeability equation that considers the pore morphology variance in different tight/ultra-tight rocks. We build an analytical equation for describing the full-Knudsen-number-ranged rarefied gas flows through single channels. By approximating this equation within a Knudsen number range of (0, 1), we develop a second-order equation of channel permeability vs. Knudsen number. In the literature, most of the second-order equations of channel permeability vs. Knudsen number were built for a 2D channel. Herein, we establish such second-order relation with different sets of parameter values valid for the rarefied gas flows in a cylinder, in a triangular prism, and in a duct, respectively. After checking the relation between a Knudsen number and real gas properties, we further transform the second-order equation in terms of Knudsen number into a second-order equation in terms of the reciprocal of gas pressure. We then quantify how a channel morphology influences the parameter values in the permeability equation. Accordingly, a constraint on the parameters of the permeability equation is proposed by considering the most observed pore morphologies in tight/ultra-tight rocks. The second-order permeability equation with the constraint is utilized to well fit Lattice Boltzmann simulations on reconstructed rock samples and multiple sets of permeability data that are measured in the literature. When being used to fit the measured permeability data of gas flows at pressures of above 0.5 MPa in the rocks with an intrinsic permeability of below 0.1 μD, the proposed second-order permeability equation demonstrates superiority to the permeability equations selected from the literature. The regressed values of the parameters in the proposed permeability equation suggest that the dominant pores in tight and ultra-tight rocks would normally have a rectangular cross-section, a circular cross-section, or a triangular cross-section. The proposed equation with the constraint offers a simpler quantitative description of the interplay among pore morphology, gas properties, and tight/ultra-tight rock permeability than the permeability equations in the literature.

Medial collateral ligament release during knee arthroscopy: key concepts.

Complete access to the posterior medial compartment of the knee may represent a technical challenge during arthroscopy in patients with a tight tibiofemoral joint space.Medial collateral release reduces direct iatrogenic cartilage damage in the medial compartment of the knee through manipulation with instruments.We recommend performing medial collateral release in surgeries that access the posteromedial compartment (e.g. partial meniscectomy for ruptures of the posterior horn of medial meniscus or posterior root repairs) when the patient has a tight tibiofemoral joint space.There are two main techniques to perform medial collateral release: inside-out and outside-in. Regardless of the technique used, releasing medial ligament structures is a safe and effective method to be used in the diagnosis and treatment of injuries to the medial compartment. Cite this article: EFORT Open Rev 2021;6:669-675. DOI: 10.1302/2058-5241.6.200128

On the cardinality of separable pseudoradial spaces

The aim of this paper is to consider questions concerning the possible maximum cardinality of various separable pseudoradial (in short: SP) spaces. The most intriguing question here is if there is in ZFC a regular (or just Hausdorff) SP space of cardinality >c. While this question is left open, we establish a number of non-trivial results that we list below.•It is consistent with MA+c=ℵ2 that there is a countably tight and compact SP space of cardinality 2c.•If κ is a measurable cardinal then in the forcing extension obtained by adding κ many Cohen reals, every countably tight regular SP space has cardinality at most c.•If κ>ℵ1 Cohen reals are added to a model of GCH then in the extension every pseudocompact SP space with a countable dense set of isolated points has cardinality at most c.•If c≤ℵ2 then there is a 0-dimensional SP space with a countable dense set of isolated points that has cardinality greater than c.

Ble Based Indoor Positioning System and Minimal Zone Searching Algorithm (MZS) Applied to Visitor Trajectories within a Museum

Museums are perfect experimentation grounds for indoor positioning technologies. Indeed, museum managers are always pleased to hold these kinds of events where it offers the opportunity to the public to be a part of such experimentation and allowing us at the same time to popularize our research with them. In this paper, we describe an experiment that held within the museum of natural history of La Rochelle with a class of high school volunteers. We will explain our systems that has been built to work in this specific case, and among other things formalize our algorithm for indoor localization that has not had an equivalent in the state of the art. The minimal zone searching algorithm (MZS) can compute in real time the position of a visitor, shaped as a zone with an average surface of 3 m2 when resources are limited and when the placement of nodes must respect the constraints imposed by the room’s layout. This method offered good results with data collected during the experimentation, such as a meaningful representation of the position of a visitor and most importantly a stable execution during the whole experience even when the subject was in tight spaces.

Laparoscopic pancreatectomy for pancreatic cancer with advanced energy device (LigaSure Maryland jaw device)

Pancreatic cancer is well known to be one of the most lethal malignant diseases in gastrointestinal tract. As a monotherapy, margin-negative radical pancreatectomy is regarded as the most potent anticancer treatment. However, to enhance the oncologic efficacy of curative resection, postoperative chemotherapy should be considered. As a matter of fact, it is estimated that pancreatic cancer will be the second most common cancer-related human mortality in 2030, which will be main theme regarding human health issue. With advance of pancreatic surgery, developing method for early diagnosis, understanding tumor biology, and introduction of new potent chemotherapeutic agents, pancreatic cancer is expected to face new paradigm in near future. Especially in treating pancreatic cancer, surgical extirpation is very important. Due to anatomical complexity, and surgical difficulty, laparoscopic radical pancreatectomy in treating pancreatic cancer is still controversial. However, currently available data are showing its feasibility, safety, and equivalent oncologic outcomes comparing with open surgical approach in well selected patients. There are potential theoretical advantages of laparoscopic pancreatectomy. Early recovery with less surgical stress is expected to provide the patients with appropriate patients' condition to receive the postoperative adjuvant chemotherapy, which is inevitable requirement for the long-term survival. Therefore, in performing laparoscopic radical pancreatectomy for pancreatic cancer, surgeons need for effective energy device in dissecting the pancreas for safe and effective margin-negative resection. It is thought that LigaSure Maryland jaw device can be appropriate in performing laparoscopic radical pancreatectomy for pancreatic cancer due to following several reasons; 1) Burst pressure 2) Temperature 3) Nano-coating 4) Blunt dissection. Obtaining superior mesenteric artery (SMA) lateral margin is crucial in pancreatic head cancer. Very narrow space is allowed for securing SMA lateral margin. Alternative advanced energy device, Sonicision curved jaw cordless ultrasonic dissection system, can enhance the surgical performance and safety. Thin and small curved blade (0.8 mm-1.7 mm) can provide easy access to the tight space with less potential thermal damage near the major vascular structure. In this presentation, I would like to discuss our clinical practice of laparoscopic pancreatectomy for pancreatic cancer with advanced energy device.

Design and construction of the mechanical structure for thin-gap RPC triplets for the upgrade of the ATLAS muon spectrometer

The advent of thin-gap RPCs, with 1 mm gas gaps instead of 2 mm in the present RPCs, opened the possibility to instrument the inner barrel layer of the ATLAS muon spectrometer where there is very limited amount of space in radial direction from the beam line. The environment is particularly dense in the barrel end-cap transition region. A compact mechanical structure coping with the expected thickness variations of the assembled RPCs is needed to fit into the limited available space. At the same time the mechanical structure must be sufficiently rigid to keep the deformations of the RPC packages within the allowed envelopes. The tight space constraints make it impossible to achieve the required rigidity with thick paper honeycomb plates as used in the present ATLAS RPCs. For the phase I upgrade of the barrel end-cap transition region of the ATLAS muon spectrometer three 1 mm gap RPCs are put into an aluminium frame. In this frame the RPC triplet is compressed with pre-bent 2 mm thick aluminium plates. The rigidity of the frame is achieved by stiffening rods connecting the lateral structure of the frame. The same concept can be used for the phase II upgrade of the inner layer of the muon spectrometer.

Removal of Total Coliform and TSS for Hospital Wastewater by Optimizing the Role of Typha Angustifolia and Fine Sand-Gravel Media in Horizontal Sub Surface Flow Constructed Wetland

This study aims to evaluate the performance of a pilot-scale HSSF-CW utilizing Typha angustifolia and fine sand-gravel media in removing total coliform and TSS from hospital wastewater. Three pilot-scale HSSF-CW cells measuring 1.00 x 0.45 x 0.35 m3 were filled with gravel sand media with a diameter of 5 - 8 mm as high as 35 cm with a submerged media depth of 0.30 m. There were three treatments, namely the first cell (CW1) without plants, the second cell (CW2) was planted with a density of 12 Typha angustifolia plants, and the third cell (CW3) was planted with a density of 24 Typha angustifolia plants. The three HSSF-CW cells received the same wastewater load with total coliform and TSS contents of 91000 MPN / 100 mg and 53 mg / L, respectively, with Hydraulic Loading Rates 3,375 m3 per day. Wastewater was recirculated continuously to achieve the equivalent HSSF-CW area requirement. The experimental results show that the performance of CW3 is more efficient than CW1 and CW2 in total coliform and TSS removal for hospital wastewater. The pollutant removal efficiency at CW3 reached 91.76% for total coliform with one day hydraulic retention time and 81.00% for TSS with two days of hydraulic retention time. This study concludes that the HSSF-CW system using sand-gravel media with a diameter of 5 - 8 mm with a submerged media depth of 0.30 m and planted with Typha angustifolia with a tighter spacing proved to be more efficient in removing total coliform and TSS from hospital wastewater.

Cable deployment system for unmanned ground vehicle (UGV) mobile microgrids

An ad hoc autonomous mobile microgrid system requires electrical connections to be formed between physically separated resources. This work proposes the use of unmanned ground vehicles (UGVs) as the means to deploy the electrical cable that creates these connections. This operation requires careful control of the cabling at variable speeds to avoid entanglement with the deploying UGV or obstacles in complex outdoor environments. Searching for a product that could supply the needed control and flexibility revealed a lack of compact and low-cost options. Existing options are very heavy (>100 lbs) and do not supply precision in their deployment. There is no commercial off-the-shelf option available for small-scale cable deployment operations with size and weight constraints. To fulfill the application requirements and to combat this deficiency, a custom design and build of an “Adjustable Cable Management Mechanism” (ACMM) was required. This ACMM provides a low cost, compact platform for powered and controlled deployment and retraction of different-sized cable under moderate loads, utilizing Commercial Off-The-Shelf components (COTS). Employing this design has enabled a variety of tasks that require distribution of electrical or data cables to be accomplished for small-scale projects. The goal of this paper is to give detailed design specifications of the ACMM and instructions on how to recreate it and calibrate it to be useful for tethering robots in various applications such as steep terrain, internet connection through tight spaces, or electrical connection between nodes for complex microgrids.

Orbital stability of compact three-planet systems – II: post-instability impact behaviour

ABSTRACT Recent observational missions have uncovered a significant number of compact multi-exoplanet systems. The tight orbital spacing of these systems has led to much effort being applied to the understanding of their stability; however, a key limitation of the majority of these studies is the termination of simulations as soon as the orbits of two planets cross. In this work we explore the stability of compact, three-planet systems, and continue our simulations all the way to the first collision of planets to yield a better understanding of the lifetime of these systems. We perform over 25 000 integrations of a Sun-like star orbited by three Earth-like secondaries for up to a billion orbits to explore a wide parameter space of initial conditions in both the co-planar and inclined cases, with a focus on the initial orbital spacing. We calculate the probability of collision over time and determine the probability of collision between specific pairs of planets. We find systems that persist for over 108 orbits after an orbital crossing and show how the post-instability survival time of systems depends upon the initial orbital separation, mutual inclination, planetary radius, and the closest encounter experienced. Additionally, we examine the effects of very small changes in the initial positions of the planets upon the time to collision and show the effect that the choice of integrator can have upon simulation results. We generalize our results throughout to show both the behaviour of systems with an inner planet initially located at 1 and 0.25 AU.

Shoulder strap fixation of LUCAS-2 to facilitate continuous CPR during non-supine (stair) stretcher transport of OHCAs patients

Early recognition and rapid initiation of high-quality cardiopulmonary resuscitation (CPR) are key to maximising chances of achieving successful return of spontaneous circulation in patients with out-of-hospital cardiac arrests (OHCAs), as well as improving patient outcomes both inside and outside hospital. Mechanical chest compression devices such as the LUCAS-2 have been developed to assist rescuers in providing consistent, high-quality compressions, even during transportation. However, providing uninterrupted and effective compressions with LUCAS-2 during transportation down stairwells and in tight spaces in a non-supine position is relatively impossible. In this study, we proposed adaptations to the LUCAS-2 to allow its use during transportation down stairwells and examined its effectiveness in providing high-quality CPR to simulated OHCA patients. 20 volunteer emergency medical technicians were randomised into 10 pairs, each undergoing 2 simulation runs per experimental arm (LUCAS-2 versus control) with a loaded Resusci Anne First Aid full body manikin weighing 60 kg. Quality of CPR compressions performed was measured using the CPRmeter placed on the sternum of the manikin. The respective times taken for each phase of the simulation protocol were recorded. Fisher’s exact tests were used to analyse categorical variables and median test to analyse continuous variables. The LUCAS-2 group required a longer time (~ 35 s) to prepare the patient prior to transport (p < 0.0001) and arrive at the ambulance (p < 0.0001) compared to the control group. The CPR quality in terms of depth and rate for the overall resuscitation period did not differ significantly between the LUCAS-2 group and control group, though there was a reduction in both parameters when evaluating the device’s automated compressions during transport. Nevertheless, the application of the LUCAS-2 device yielded a significantly higher chest compression fraction of 0.76 (p < 0.0001). Our novel adaptations to the LUCAS-2 device allow for uninterrupted compressions in patients being transported down stairwells, thus yielding better chest compression fractions for the overall resuscitation period. Whether potentially improved post-OHCA survival rates may be achieved requires confirmation in a real-world scenario study.

Long-Chain Fatty Acids in Bones and Their Link to Submicroscopic Vascularization Network: NMR Assignment and Relaxation Studies under Magic Angle Spinning Conditions in Intramuscular Bones of Atlantic Herring Fish.

The long-lasting proton signals in bones are identified as long-chain fatty acids, including saturated, mono-, and di-unsaturated fatty acids, with direct nuclear magnetic resonance evidence. We used intramuscular bones from Atlantic Herring fish to avoid interference from lipid-rich marrows. The key is to recognize that these signals are from mobile phase materials and study them with J-coupled correlation spectroscopies under magic angle spinning conditions. We kept extensive 1H-spin-echo records that allowed us to examine the effect of magic angle spinning on the transverse relaxation time of water and lipids over time. While it is impossible to distinguish based on chemical shifts, the relaxation data suggest that the signals are more consistent with the interpretation of phospholipid membranes than triglycerides in lipid droplets. In particular, the simultaneous T2 changes in water and lipids suggest that the centrifugal impact of magic angle spinning alters the lipid's structure in very tight spaces. Additional evidence of phospholipid membranes came from the choline-γ resonance at 3.2 ppm in fresh samples, which disappears with magic angle spinning. Thus, the fatty acid signals are at least partially from membrane bilayer structures, and we propose that they are linked to the submicroscopic vascularization channels similar to the dense canaliculi network in mammalian bones. Our detection of phospholipids from bones depended critically on two factors: (1) the elimination of the overwhelming triglyceride signals from marrows and (2) the preservation of water that biomembranes require. The relaxation data reveal aspects of lipid fluidity that have not been elucidated by previous order parameter studies on model membranes. Relaxation times have long been considered difficult to interpret. A robust and renewed understanding may be beneficial.

Production and carbon allocation in clonal Eucalyptus plantations under different planting spacings

Wood productivity in plantation forests depends on successful choices of genetic materials and silvicultural practices. Wisely defining the intitial tree spacing according to edaphoclimatic conditions is important as spacing influences the amount of water, nutrients and light available for each tree. Resource availability, in turn, influences some important processes controlling wood production such as tree survival, CO2 uptake, and partitioning of photosynthates to stem wood and other tree compartments. Different genotypes may respond differently to tree spacing, due to possible differences in their canopy structure, physiology, and strategies for soil ressources acquisitions and carbon allocations. Our objective in this study was to investigate the interactive effects of genotype and tree spacing on wood production of fast-growing clonal eucalypt plantations in Southeastern Brazil. Tree growth, gross primary production (GPP) and partitioning of GPP to total belowground carbon flux (TBCF), wood and leaf production, and aboveground respiration were assessed in an experimental trial involving three commercial E. urophylla clones (AEC 0144, AEC 224 and COP 1404) planted at two spacings (3 m × 2 m; 3 m × 4 m). We hypotetized that (1) the most productive genotypes are those with both the highest GPP and the highest carbon partitioning to stem wood production; and (2) at closer spacing, leaf area index (LAI) and GPP are higher, but the partitioning to wood production is lower, and the belowground partitioning is higher, due to reduced soil water and nutrients availability per tree. Biomass and LAI were measured at ages 40 months (mid-rotation) and 52 months, and GPP, TBCF, wood production and leaf production were estimated between these two stand ages. Stem biomass and LAI were higher, for all clones, at the closer spacing (3 m × 2 m), as we could have expected since this spacing (corresponding to a stocking of 1667 tree ha−1) is the most commonly chosen in industrial eucalypt plantations in this region. Consistently with clonal ranking established in other studies, at spacing 3 m × 2 m clones were ranked as AEC 0144 > AEC 224 > COP 1404 for their wood production, but this ranking almost vanished at wide spacing. Our first hypothesis was supported by data: at spacing 3 m × 2 m the most productive clones (AEC 0144 > AEC 224 > COP 1404) were those with both the highest GPP (6.14 > 4.63 > 4.57 kg C m−2 year−1) and the highest carbon partitioning to wood production (0.33 > 0.29 > 0.26), although the differences between COP 1404 and AEC 224 were not significant (at P = 0.05). Our second hypothesis was only partially supported by data: wood biomass at age 40 months was higher at the closer spacing, but this positive effect of tight spacing seemed to decrease with stand age, as wood production and GPP measured between ages 40 and 52 months remained higher at the closer spacing only for clone AEC 0144. There was no consistent difference in the partitioning of GPP to wood production between the two spacings. The age-related decrease of the positive effect of high stockings may result from a faster depletion of deep soil water reserves in dense stands.

SRFabric: A Semi-Reconfigurable Rack Scale Topology

Rack scale design is a promising trend towards customized hardware design, where high density clusters of SoCs are integrated in the rack. One of the biggest challenges for rack scale computing is the interconnection network. Traditional data center topologies require too many ToR switches to support hundreds of SoCs, while distributed fabrics deliver a considerably high end-to-end latency and network oversubscription. Since no one topology fits all kinds of workloads, a flexible in-rack topology requires a careful redesign to dynamically adapt to diverse data center traffic within tight cost and space constraints in the rack. SRFabric is a semi-reconfigurable rack scale network topology that exploits the high path diversity, the cost-effectiveness of distributed fabrics, and the dynamic reconfigurability of circuit switches. This is accomplished by enabling multiple static ports and dynamic ports for each SoC. Leveraging the partial link reconfigurability, SRFabric is able to optimize its topology to dynamically adapt to various workload patterns. We further propose the design of SRFabric to decide the nearly optimal number of dynamic ports and static ports for expected communication density and performance. Extensive evaluations demonstrate that SRFabric can deliver lower average path length, i.e., 2.21 hops on average, and higher bisection bandwidth, i.e., up to 77% nonblocking bandwidth, and provide comparable performance with state-of-the-art strategy XFabric at a lower cost, i.e., XFabric costs up to 3 times more than that of SRFabric.

Finite-dimensional boundary uniform stabilization of the Boussinesq system in Besov spaces by critical use of Carleman estimate-based inverse theory

Abstract We consider the 𝑑-dimensional Boussinesq system defined on a sufficiently smooth bounded domain and subject to a pair { v , u } \{v,\boldsymbol{u}\} of controls localized on { Γ ~ , ω } \{\widetilde{\Gamma},\omega\} . Here, 𝑣 is a scalar Dirichlet boundary control for the thermal equation, acting on an arbitrarily small connected portion Γ ~ \widetilde{\Gamma} of the boundary Γ = ∂ ⁡ Ω \Gamma=\partial\Omega . Instead, 𝒖 is a 𝑑-dimensional internal control for the fluid equation acting on an arbitrarily small collar 𝜔 supported by Γ ~ \widetilde{\Gamma} . The initial conditions for both fluid and heat equations are taken of low regularity. We then seek to uniformly stabilize such Boussinesq system in the vicinity of an unstable equilibrium pair, in the critical setting of correspondingly low regularity spaces, by means of an explicitly constructed, finite-dimensional feedback control pair { v , u } \{v,\boldsymbol{u}\} localized on { Γ ~ , ω } \{\widetilde{\Gamma},\omega\} . In addition, they will be minimal in number and of reduced dimension; more precisely, 𝒖 will be of dimension ( d - 1 ) (d-1) , to include necessarily its 𝑑-th component, and 𝑣 will be of dimension 1. The resulting space of well-posedness and stabilization is a suitable, tight Besov space for the fluid velocity component (close to L 3 ⁢ ( Ω ) \boldsymbol{L}^{3}(\Omega) for d = 3 d=3 ) and a corresponding Besov space for the thermal component, q &gt; d q&gt;d . Unique continuation inverse theorems for suitably over-determined adjoint static problems play a critical role in the constructive solution. Their proof rests on Carleman-type estimates, a topic pioneered by M. V. Klibanov since the early 80s.