Research on Ventilation and Heat Insulation Layer Design of Split-Type Roof Greening Based on Topological Interlocking Principle

In this paper,the roof ventilation and heat insulation layer modules are combined with the roof greening,and each module is assembled through the principle of topological interlocking.The assembly of these modules does not require any rivets or cement mortar,and the structural stability of the overall assembled roof is achieved only through the interlocking and limiting the movements of the interlocked units.The green roof designed in this paper has strong applicability and can be applied to roofs of different shapes.Such a roof can not only meet the aesthetic needs,but also beautify the urban environment and reduce carbon emissions.

Comparative study of intertrochanteric fracture fixation using proximal femoral nail with and without distal interlocking screws

BACKGROUND Intertrochanteric(IT)fracture is one of the most common fractures seen in an orthopaedic practice.Proximal femoral nailing(PFN)is a common modality of fixing IT femur fracture.We retrospectively studied whether a PFN with two proximal lag screws can be done without distal interlocking screws in the 31-A1 and 31-A2 fracture patterns according to the Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association(AO/OTA)guidelines for IT femur fractures.AIM To compare the outcomes of IT fractures(AO/OTA 31-A1 and 31-A2)treated by PFN with and without distal interlocking screws.METHODS We carried out a retrospective study of 140 patients in a tertiary care centre who had AO/OTA type 31-A1 and 31-A2 IT fractures.We divided the patients into two groups,in which one of the groups received distal interlocking screws(group 1)and the other group did not(group 2).The subjects were followed up for a mean period of 14 mo and assessed for radiological union time,fracture site collapse,mechanical stability of implant,and complications associated with the PFN with distal interlocking and without distal interlocking.Then,the results were compared.RESULTS PFN without distal interlocking screws has several advantages and gives better results over PFN with distal interlocking screws in the AO/OTA 31-A2 fracture pattern.However,similar results were observed in both groups with the fracture pattern AO/OTA 31-A1.In patients with fracture pattern AO/OTA 31-A2 treated by PFN without distal interlocking screws,there were minimal proximal lockrelated complications and no risk of distal interlock-related complications.The operative time,IITV radiation time and time to radiological union were reduced.These patients also had better rotational alignment of the proximal femur,and the anatomy of the proximal femur was well maintained.It was also noted that in the cases where distal interlocking was performed,there was a gradual decrease in neck shaft angle,which led to varus collapse and failure of bone-implant construct in 21.40%.CONCLUSION In fracture pattern AO/OTA 31-A2,PFN without distal interlocking had better results and less complications than PFN with distal interlocking.

Open Fracture Tibia Treated by Unreamed Interlocking Nail. Long Experience in El-Bakry General Hospital

Background: Internal splintage of open tibial fractures had gained acceptance as a preferred method of early stabilization of such injuries. Patients and Methods: Fifty-five patients had been operated upon. They were followed from July 2008 to March 2013 (56 months) with an average time of 39 months. The final results had been evaluated through a scheme including 7 parameters: pain, union, malunion, infection, range motions of nearby joints, implant and technical failure and activity and returning to the same work. Results: According to previous parameters, union was achieved in 52 cases (94.5%) at an average time of 20 weeks (16 - 52 weeks) with 5.5% incidence of nonunion. Excellent and good ranges of knee and ankle motions were achieved at final follow-up visit in 49 cases (89.09%). The incidence of complication was acceptable mainly malunion 7.3%, deep infection 12.7%, implant and technical failure 9.1% full activity and returning to the same work achieved in 89.1%. The overall net results of our series are as follows: excellent—19 cases (34.5%), good—27 cases (49.1%), fair—6 cases (10.9%) and poor—3 cases (5.5%). Conclusion: Utilizing unreamed interlocking nail for open tibial fractures is a good method of treatment particularly those of grade (II), and (IIIA).

Verifying the accuracy of interlocking tables for railway signalling systems using abstract state machines

Railway transportation system is a critical sector where design methods and techniques are defined by international standards in order to reduce possible risks to an acceptable minimum level. CENELEC 50128 strongly recommends the utilization of finite state machines during system modelling stage and formal proof methods during the verifi- cation and testing stages of control algorithms. Due to the high importance of interlocking table at the design state of a sig- nalization system, the modelling and verification of inter- locking tables are examined in this work. For this purpose, abstract state machines are used as a modelling tool. The developed models have been performed in a generalized structure such that the model control can be done automatically for the interlocking systems. In this study, NuSMV is used at the verification state. Also, the consistency of the developed models has been supervised through fault injection. The developed models and software components are applied on a real railway station operated by Metro Istanbul Co.

Olecranon anatomy:Use of a novel proximal interlocking screw for intramedullary nailing,a cadaver study

AIM: To define the optimum safe angle of use for an eccentrically aligned proximal interlocking screw(PIS) for intramedullary nailing(IMN).METHODS: Thirty-six dry cadaver ulnas were split into two equal pieces sagitally. The following points were identified for each ulna: the deepest point of the incisura olecrani(A), the point where perpendicular lines from A and the ideal IMN entry point(D) are intersected(C) and a point at 3.5 mm(2 mm safety distance from articular surface + 1.5 mm radius of PIS) posterior from point A(B). We calculated the angle of screws inserted from point D through to point B in relation to D-C and B-C. In addition, an eccentrically aligned screw was inserted at a standard 20° through the anterior cortex of the ulna in each bone and the articular surface wasobserved macroscopically for any damage.RESULTS: The mean A-C distance was 9.6 mm(mean ± SD, 9.600 ± 0.763 mm), A-B distance was 3.5 mm, C-D distance was 12.500 mm(12.500 ± 1.371 mm) and the mean angle was 25.9°(25.9°± 2.0°). Lack of articular damage was confirmed macroscopically in all bones after the 20.0° eccentrically aligned screws were inserted. Intramedullary nail fixation systems have well known biological and biomechanical advantages for osteosynthesis. However, as well as these well-known advantages, IMN fixation of the ulna has some limitations. Some important limitations are related to the proximal interlocking of the ulna nail. The location of the PIS itself limits the indications for which intramedullary systems can be selected as an implant for the ulna. The new PIS design, where the PIS is aligned 20°eccentrically to the nail body, allows fixing of fractures even at the level of the olecranon without disturbing the joint. It also allows the eccentrically aligned screw to be inserted in any direction except through the proximal radio-ulnar joint. Taking into consideration our results, we now use a 20° eccentrically aligned PIS for all ulnas. In our results, the angle required to insert the PIS was less than 20° for only one bone. However, 0.7° difference corresponds to placement of the screw only 0.2 mm closer to the articular surface. As we assume 2.0 mm to be a safe distance, a placement of the screw 0.2 mm closer to the articular surface may not produce any clinical symptoms.CONCLUSION: The new PIS may give us the opportunity to interlock IMN without articular damage and confirmation by fluoroscopy if the nail is manufactured with a PIS aligned at a 20.0° fixed angle in relation to the IMN.

Design of Railway Computer Interlocking Search Algorithm and Implementation of Interlocking Software

The computer interlocking system has a wide application in realizing interlocking control between the switch, the signal, and the track circuit in station. Due to the similarity between the binary tree and the station-type data structure, the actual station route search method and the recursive algorithm are combined inorder to realize the computer interlocking route search. On this basis, through the design of switch class, track circuit class and signal machine class, by using C++ object-oriented the management of station data structure and entity object are realized, and then the crowding alarm, switch operations and so on in computer interlocking software. Taking the implementation of 5# station computer interlocking software as an example and based on are realized C++ the object-oriented computer interlocking software is written to provide a reference for realizing the railway computer interlocking training system function.

Experimental studies on interface mechanism of interlocking attachment of porous titanium

The feature of porous titanium is that new bone trabecular tissue could ingrow intoits pores and produce interlocking attachment.The spherical TC4 powder and titanium fiberwere seperately implanted into the femurs of 24 dogs.The pore size of the samples was0.24mm and their rates of porosity were 40%～50%.After 3 months,the interface shearstrength examined by straight pulling test,was over 4.60±0.36MPa.Scanning electronmicroscopy showed that there were new bone components in the porous layer.Lightmicroscopy also revealed that there were new bone lacunae and their pathways in it.Thedepth of the reforming bone was 3 mm.Interface shear strength of the new bone in the po-rous layer might meet the need of load bearing.Porous materials would prevent the artificialjoint from loosening and thus help to develop a new service clinically.

Comparison of straight median sternotomy and interlocking sternotomy with respect to biomechanical stability

AIM: To increase the stability of sternotomy and so decrease the complications because of instability. METHODS: Tests were performed on 20 fresh sheep sterna which were isolated from the sterno-costa joints of the ribs. Median straight and interlocking sternotomies were performed on 10 sterna each, set as groups 1 and 2, respectively. Both sternotomies were performed with an oscillating saw and closed at three points with a No. 5 straight stainless-stee wiring. Fatigue testing was performed in craniocaudal, anterio-posterior(AP) and lateral directions by a computerized materials-testing machine cycling between loads of 0 to 400 N per 5 s(0.2 Hz). The amount of displacement in AP, lateral and craniocaudal directions were measured and also the op-posing bone surface at the osteotomy areas were calculated at the two halves of sternum. RESULTS: The mean displacement in cranio-caudal direction was 9.66 ± 3.34 mm for median sternotomy and was 1.26 ± 0.97 mm for interlocking sternotomy, P < 0.001. The mean displacement in AP direction was 9.12 ± 2.74 mm for median sternotomy and was 1.20 ± 0.55 mm for interlocking sternotomy, P < 0.001. The mean displacement in lateral direction was 8.95 ± 3.86 mm for median sternotomy and was 7.24 ± 2.43 mm for interlocking sternotomy, P > 0.001. The mean surface area was 10.40 ± 0.49 cm2 for median sternotomy and was 16.8 ± 0.78 cm2 for interlocking sternotomy, P < 0.001. The displacement in AP and cranio-caudal directions is less in group 2 and it is statistically significant. Displacement in lateral direction in group 2 is less but it is statistically not significant. Surface area in group 2 is significantly wider than group 1.CONCLUSION: Our test results demonstrated improved primary stability and wider opposing bone surfaces in interlocking sternotomy compared to median sternotomy. This method may provide better healing and less complication rates in clinical setting, further studies are necessary for its clinical implications.

Near is more:learning efficiency in research and development innovation among interlocking firms

Research question/issue:This study examines whether geographic proximity produces a proximity preference as interlocking firms observe each other and learn innovative behaviors through information transmission among interlocking directors.Research findings/insights:We study the performance of A-share-listed companies in China from 2007 to 2017 on the basis of resource dependence theory,agglomeration effect theory,and Porter’s competitive theory.When target firms learn about research and development–related innovation behaviors from interlocking firms closer to them,they experience more efficient learning effects and have improved convergent traits.Moreover,this proximity advantage increases the willingness of the target firm to communicate with and learn from interlocking firms closer to them.Highly developed areas and research and development–intensive industries positively affect the learning efficiency of interlocking firms.Theoretical/academic implications:Our conclusion is consistent with resource dependence theory;target firms in highly developed areas are more willing to imitate and study nearby interlocking firms to maintain their peer relations,innovation potential,and competitiveness.Our conclusion is also consistent with competition theory,which states that the exchange of information between target firms in highly research and development–intensive industries and distant interlocking firms increases innovation differentiation,innovation potential,and competitiveness,even when such exchange has a high cost.Practitioner/policy implications:The results support resource dependence theory and peers’effects.The information obtained by interlocking directorates through external social relations guides firm decision-making,and closer distances reveal more obvious effects.

Investigation of the Effect of the Addition of Petroleum Waste to Interlocking Bricks Constituent

Incinerator ash was investigated for its potential use as a replacement for sand and cement in concrete interlocking bricks. The physical characteristics of the raw materials were examined. Two sets of mixes were prepared. For the first set, sand and water quantities were fixed while incinerator ash was used at 0% to 100% replacement by weight for cement in steps of 10%. In the second set, incinerator ash was used at 0% to 100% replacement by weight for sand while cement and water quantities was fixed. The mixing proportions for cement, sand and water were 1:3:0.7, respectively. Compressive strength and leachability tests were performed on the specimens. Results showed that the replacement of sand by incinerator ash up to 40% exhibited higher compressive strength than the control mix (0% incinerator ash) after 28 days curing. Maximum compressive strength of 33.33N/mm2 was obtained after 28 days curing using using 20% incinerator ash substitution for sand. Replacement of cement by incinerator ash up to 20% exhibited higher compressive strength than the control mix. Compressive strength of 28.2 N/mm2 was achieved after 28 days curing period using a 20% ash substitution for cement. Leaching of heavy metals (Pb and Cd ) present in the ash was observed in concentrated nitric acid.

Treatment of femur supracondylar fracture with retrograde interlocking intramedullary nails in elderly patients

Objective： To report 32 cases of femur supracondylar fracture treated with retrograde interlocking intramedullary nails in elderly patients. Methods： According to the AO classification, all of 32 cases were classified as extra-articular type A. 32 cases were treated with interlocking intramedullary nail by closed insertion from intercondylar fossa of the knee. All cases accepted CPM exercise as early as possible after operation. Results： Following up 5 to 15 months, all fractures united within an average duration of 5.3 months （4-7 months）. According to the Shelbourne scale, the excellent rate of the knee function was 86.3%. Conclusion： Retrograde interlocking intramedullary nail is useful alternative implant for the treatment of osteoporotic supracondylar fracture of femur, particularly of the type A fracture in the elderly population. Its merits include stable fixation, high rate of fracture union and few complications.

Report of a New Case of Interlocking Heads in a Breech-Vertex Twin Delivery: A Conversation with My Residents

“Locked twins” is a rare event occurring in about 1 in every 1000 twin births. A 21-year-old primigravida with a 31-week twin pregnancy was admitted for delivery. The head of the first twin was locked to the chin of the second twin at the top of the symphysis pubis. Caesarean section was performed allowing the delivery of both dead twins. Twins gestations with first twin in the breech presentation raise index of suspicion of potential locked twin. However, management of such situation is controversial with most authors and colleges recommending caesarean section to avoid interlocking heads. We report another rare case of interlocking heads and bring up the topic about management of breech-first twin deliveries.

Interlocking System for CBTC (Communication Based Train Control) System

In recent years,the environment of railways and the systems such as CBTC(communication based train control)have been changing.To respond the changes and the needs of customers,a UTCS(unified train control system)has been developed to realize a system that evolves with customers.Previous type systems consist of independent components such as ATC(Automatic train control)system,electronic interlocking system,and facility monitoring system,and there are a complicated overlap of system configurations and functions and difference in concept between the systems.On the other hand,the integrated train control system consists of horizontal layers such as function layer,network layer,and terminal layer.Therefore,the system has been developed to make it simple with no unnecessary redundancy and evolving to meet the needs of customers.In this paper,we explain a method that realizes the interlocking function for CBTC system in the function layer based on the concept of“securing a train travelling path”including path blocking and routing,and evaluate the safety of the method using STAMP/STPA.

Study on the Application of Non-Plastering Technology of BM Lightweight Aggregate Interlocking Block

Benchmark(BM)lightweight aggregate interlocking block has the characteristics of energy saving,no plastering,convenient construction,etc.,which can be used for internal infilled walls at all parts(240 mm thick block can also be used for external infilled walls).The U-shaped bricks are used in building ring beams,structural columns and lintel formwork.It eases the formwork construction process,saves energy consumption,shortens the construction period,and reduces the materials used,achieving the purpose of ensuring a high-quality building at minimum construction cost.Taking the practical project as an example,this paper studies the performance and characteristics of BM light aggregate interlocking block,and introduces the key construction technologies,aiming to provide relevant reference for the application of BM light aggregate interlocking block in practical projects.

Wire-feed laser additive manufacturing of dissimilar metals via dual molten pool interface interlocking mechanism

Intermetallic compounds produced in laser additive manufacturing are the main factors restricting the joint performance of dissimilar metals.To solve this problem,a dual molten pool interface interlocking mechanism was proposed in this study.Based on a dual molten pool interface interlocking mechanism,the dissimilar metals,aluminum alloy and stainless steel,were produced as single-layer and multilayer samples,using the wire-feed laser additive manufacturing directed energy deposition technology.The preferred parameters for the dual molten pool interface interlocking mechanism process of the dissimilar metals,aluminum alloy and stainless steel,were obtained.The matching relationship between the interface connection of dissimilar metals and the process parameters was established.The results demonstrated excellent mechanical occlusion at the connection interface and no apparent intermetallic compound layer.Good feature size and high microhardness were observed under a laser power of 660 W,a wire feeding speed of 55 mm/s,and a platform moving speed of 10 mm/s.Molecular dynamics simulations demonstrated a faster rate of aluminum diffusion in the aluminum alloy substrate to stainless steel under the action of the initial contact force than without the initial contact force.Thus,the dual molten pool interface interlocking mechanism can effectively reduce the intermetallic compound layer when dissimilar metals are connected in the aerospace field.

Numerical analysis of a double interlocking padded finger seal performance based on thermo-fluid-structure coupling method

Non-contacting finger seals represent an advanced non-contacting and compliant seal in gas turbine sealing technology.This paper proposes a new structure of noncontacting finger seals with double interlocking pads.The numerical analysis model based on the thermo-fluid-structure coupling method for the new type finger seal was established.The influence of working conditions on leakage of the seal was studied and compared with the single padded non-contacting finger seal.The results show that the interface between the bottom of the finger pad and rotor surface is the main leakage path that forms the gas film with obvious variations of pressure and flow velocity.Under high temperature and high pressure operating conditions,the hydrodynamic effect of the gas film is enhanced,and lifting force is significantly improved.The deformation of fingers is composed of elastic deformation and thermal deformation.At room temperature,the deformation of fingers is mainly elastic deformation and points to the center of the rotor,which reduces the gas film clearance.The deformation of fingers at high temperature and high pressure creates a circumferentially convergent gap between the bottom of the pad and the rotor,which is beneficial to improve the loading capacity and to reduce leakage of the seal.Compared with the typical single padded noncontacting finger seal,the double interlocking padded finger seal proposed in this paper reduces the leakage factor by about 37%,which provides an advanced seal concept with the potential to improve sealing performance under high temperature and high pressure working conditions.

Mortarless structures based on topological interlocking

We review the principle of topological interlocking and analyze the properties of the mortarless structures whose design is based on this principle.We concentrate on structures built of osteomorphic blocks-the blocks possessing specially engineered contact surfaces allowing assembling various 2D and 3D structures.These structures are easy to build and can be made demountable.They are flexible,resistant to macroscopic fractures and tolerant to missing blocks.The blocks are kept in place without keys or connectors that are the weakest elements of the conventional interlocking structures.The overall structural integrity of these structures depends on the force imposed by peripheral constraint.The peripheral constraint can be provided in various ways:by an external flame or features of site topography,intemal prestressed cables/tendons,or self-weight and is a necessary auxiliary element of the structure.The constraining force also determines the degree of delamination developing between the blocks due to bending and thus controls the overall flexibility of the structure thus becoming a new design parameter.

Fracture Union in Closed Interlocking Nail in Humera Shaft Fractures

Background： Fracture shaft humerus is a major cause of morbidity in patients with upper extremity injuries. The aim of this study was to evaluate the outcome of interlocking nail in humeral shaft fractures. Methods： This study was conducted in the Department of Orthopedic Surgery in SMS and R Sharda University from January 2010 to November 2013. Seventy-eight patients were recruited from emergency and out-patient department having a close fracture of humerus shaft. All patients were operated under general anesthesia and closed reamed interlocking nailing was done. All patients were followed for 9 months. Results： Out of 78 patients, 69 patients underwent union in 90-150 days with a mean of I 10.68 days. Complications found in four patients who had nonunion, and five patients had delayed union, which was treated with bone grafting. All the patients were assessed clinically and radiologically for fracture healing joint movements and implant thilure. The results were excellent in 88.46% and good in 6.41% patients. Complete subjective, functional, and clinical recovery had occurred in almost 100% of the patients. ConcLusions： The results of the present study indicates that in the presence of proper indications, reamed antegrade intramedullary interlocked nailing appears to be a method of choice for internal fixation ofosteoporotic and pathologic fractures.

Bioinspired mechanically interlocking holey graphene@SiO_(2)anode

Mechanically interlocking structures that can enhance adhesion at the interface and regulate the stress distribution have been widely observed in biological systems.Inspired by the biological structures in the wings of beetles,we synthesized a holey graphene@SiO_(2)anode with strong mechanical interlocking,characterized it electrochemically,and explained its performance by finite element analysis and density functional calculations.The mechanically interlocking structure enhances lithium-ion(Li^(+))storage by transmitting the strain from SiO_(2)to the holey graphene and by a mechano-electrochemical coupling effect.The interlocking fit hinders the abscission of SiO_(2)and the distinctive structure reduces the stress and strain of SiO_(2)during(de)lithiation.The positive mechano-electrochemical coupling effect preserves the amount of electrochemically active phase(LixSi)during cycles and facilitates Li+diffusion.Therefore,the capacity shows only a slight attenuation after 8000 cycles(cycling stability),and the specific capacity is~1200 mA h g^(−1)at 5 A/g(rate-performance).This study furnishes a novel way to design high-performance Li^(+)/Na+/K^(+)/Al3^(+)anodes with large volume expansion.

Microstructure and Improved Thermal Shock Behaviour of an In Situ Formed Metal-Enamel Interlocking Coating

A novel metal-enamel interlocking coating was designed and prepared in situ by co-deposition of Ni-enamel composite layer and subsequent air spray of enamel with 10 wt% nanoscale Ni. During the firing process, the external enamel layer was melted and jointed with the enamel particles at the upper part of the Ni-plating layer to form the enamel pegs. Thermal shock tests of pure enamel, enamel with 10 wt% Ni composite and metal-enamel interlocking coatings were conducted at 600 °C in water and static air. The results indicated that the metal-enamel interlocking showed superior thermal shock resistance to both pure enamel and enamel with 10 wt% Ni composite coatings. The enhanced performance was mainly attributed to the advantageous effects of mechanical interlocking of the enamel pegs formed at the enamel/Ni-plating interface. Meanwhile, during thermal shock test, big clusters formed by nanoscale Ni agglomerations were oxidised to be a Ni/NiO core–shell structure while small single nanoscale Ni grains were oxidised completely, which both improved the thermal shock resistance of enamel coating significantly.