An Investigation into the Performances of Cement Mortar Incorporating Superabsorbent Polymer Synthesized with Kaolin

Cement-based materials are fundamental in the construction industry,and enhancing their properties is an ongoing challenge.The use of superabsorbent polymers(SAP)has gained significant attention as a possible way to improve the performance of cement-based materials due to their unique water-absorption and retention properties.This study investigates the multifaceted impact of kaolin intercalation-modified superabsorbent polymers(K-SAP)on the properties of cement mortar.The results show that K-SAP significantly affects the cement mortar’s rheological behavior,with distinct phases of water absorption and release,leading to changes in workability over time.Furthermore,K-SAP alters the hydration kinetics,delaying the exothermic peak of hydration and subsequently modifying the heat release kinetics.Notably,K-SAP effectively maintains a higher internal relative humidity within the mortar,reducing the autogenous shrinkage behavior.Moreover,K-SAP can have a beneficial effect on pore structure and this can be ascribed to the internal curing effect of released water from K-SAP.

Histological Assessment of Bone Regeneration in the Maxilla with Homologous Bone Graft:A Feasible Option for Maxillary Bone Reconstruction

Bone biomaterials have been increasingly used to reconstruct maxillary atrophic ridges.Thus,the aim of this study was to evaluate bone reconstruction in the maxilla using a homologous cortico-cancellous FFB(lyophilized)graft and verify its reliability.Eight individuals were included from 2014 to 2018.The first surgery was performed to install homologous bone blocks in the maxilla.The period of the second intervention varied between 5 months and 15 days to 11 months(≈7.93 months).The biopsies were taken from the central region of the matured graft during the surgery for implant placement.All patients presented clinical and radiographic conditions for the installation of dental implants.There was a 100%of survival rate.The histological assessment showed that the homologous block bone graft was an osteoconductive biomaterial,with connective tissue present,and newly formed bone juxtaposed on its surface.There were bone trabeculae with osteocytes and active osteoblasts with connective tissue in the mineralization process;the remodeling process can be found through the reverse lines.A limited focus of necrosis with fibrosis was detected,with small resorption and areas of inflammatory infiltrate,but without clinical significance.The homologous block bone graft can be considered a feasible option to substitute the autogenous bone graft(gold standard),with predictable clinical and favorable histological results.The patients had a shorter surgical period,low morbidity,and an unlimited amount of biomaterial available at an accessible cost.

Early-Age Properties Development of Recycled Glass Powder Blended Cement Paste:Strengths,Shrinkage,Nanoscale Characteristics,and Environmental Analysis

Recycling solid waste in cement-based materials cannot only ease its load on the natural environment but also reduce the carbon emissions of building materials.This study aims to investigate the effect of recycled glass powder(RGP)on the early-age mechanical properties and autogenous shrinkage of cement pastes,where cement is replaced by 10%,20%and 30%of RGP.In addition,the microstructure and nano-mechanical properties of cement paste with different RGP content and water to binder(W/B)ratio were also evaluated using SEM,MIP and nanoindentation techniques.The results indicate that the early-age autogenous shrinkage decreases with the increase of RGP content and W/B ratio.While the mechanical strength deteriorates due to the addition of RGP,it can be compensated by reducing the W/B ratio.Although the addition of RGP increases the total porosity of the hardened paste,it reduces the small size porosity(<50 nm).In addition,the proportions of different types of C-S-H are changed,and the volume fraction of porosity is increased,but that of hydration products of cement paste is reduced due to the incorporation of RGP.Besides its pozzolanic activity,the mitigated shrinkage deformation that RGP is generating in cement pastes is encouraging for its use as a novel supplementary cementitious material that reduces the early-age cracking risk of cement-based materials.Meanwhile,the life cycle assessments indicate that the RGP-cement component is an economical and eco-friendly novel engineering material.

Surface Modification of Fly Ashes with Carbide Slag and Its Effect on Compressive Strength and Autogenous Shrinkage of Blended Cement Pastes

Surfaces of grade III fly ashes were modified through mixing with carbide slag and calcining at 850 ℃ for 1 h. Mineralogical compositions and surface morphology of fly ashes before and after modification were characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）, respectively. Effect of surface-modified fly ashes on compressive strength and autogenous shrinkage of blended cement pastes was investigated. Microstructures of cement pastes were examined by backscattered electron （BSE） imaging and mercury intrusion porosimetry （MIP）. The experimental results showed that β-C2S was formed on the surfaces of fly ashes after modification. Hydration ofβ-C2S on the surface-modified fly ashes densified interface zone and enhanced bond strength between particles of fly ashes and hydrated clinkers. In addition, surface modification of fly ashes tended to decrease total porosity and 10-50 nm pores of cement pastes. Surface modification of fly ashes increased compressive strength and reduced autogenous shrinkage of cement pastes.

Relationship Between Autogenous Deformation and Internal Relative Humidity of High-strength Expansive Concrete

The relationship between autogenous deformation and internal relative humidity（IRH） of high-strength concrete and high-strength expansive concrete were investigated.The experimental results indicate that,there exists a good linear relationship between autogenous shrinkage and IRH of high-strength concrete but a nonlinear relationship between autogenous deformation and IRH of high-strength expansive concrete with expansive agent.The new autogenous deformation curve can be obtained by transforming the autogenous deformation data of high-strength expansive concrete,and there exists linear relationship between the autogenous deformation and IRH.The concept of ＂critical internal relative humidity＂ was proposed,which is defined as the value of IRH when autogenous deformation is zero,to effectively reflect the autogenous deformation characteristic of expansive concrete.

Pelvic floor muscle training as a persistent nursing intervention: Effect on delivery outcome and pelvic floor myodynamia

Purpose:To evaluate the effect of pelvic floor muscle training as a nursing intervention on delivery outcomes and postpartum pelvic floor myodynamia.Methods:In total,106 nulliparas were randomised into an intervention group and control group.All nulliparas participated in a pelvic floor training programme led by a midwife.A pelvic floor physical therapist measured the women’s pelvic floor myodynamia and taught them how to correctly perform pelvic muscle contractions before the intervention.A registered nurse monitored the intervention group via twice-weekly telephone checkups.The control group did not receive individual direction.Results:There were no differences in the rate of Caesarean section or elective Caesarean section between the two groups(χ^(2)=3.446,p=0.076 and χ^(2)=2.343,p=0.185,respectively).There was a difference in the timing of the second stage of labour between the two groups(t=2.101,p=0.040);no difference was observed in the timing of the other two stages of labour(t=1.771,p=0.081 and t=1.142,p=0.263,respectively).In addition,no differences were observed in the gestational weight gain(t=0.196,p=0.845),neonatal weight(t=0.113,p=0.911),rate of episiotomy(χ^(2)=0.932,p=0.351)or rate of perineal laceration(χ^(2)=0.022,p=0.982)between the two groups.The pelvic floor myodynamia of the intervention group had improved to a greater degree than that in the control group at 6 weeks and 3 months after delivery(p<0.005).Conclusion:Persistent nursing intervention for pregnant/postpartum women helped to shorten the second stage of labour and contributed to the recovery of postpartum pelvic floor myodynamia.The influence of this intervention on the delivery mode,and rates of episiotomy and perineal laceration remains unknown.Medical staff should strengthen health education programmes that involve pelvic floor functional rehabilitation.

耳后带蒂肌骨膜瓣及自体骨粉在开放式乳突根治术腔填塞术中的应用研究

开放式乳突根治术是治疗中耳胆脂瘤及骨疡型中耳炎的主要手术方式,但手术后留下的宽大乳突术腔及外耳道后壁缺损给患者带来诸多不便,部分患者难以获得干耳,并影响听力重建的效果。外耳道后上壁重建术是消除开放式乳突术腔的常用手术方式,我们先前曾利用自体耳屏软骨重建外耳道后上壁及上鼓室外侧壁,术后获得接近正常的外耳道生理功能,但随着随访时间的延长,

Sedimentary characteristics and internal architecture of a river-dominated delta controlled by autogenic process:implications from a flume tank experiment

Autogenic processes are widely found in various sedimentary systems and they play an important role in the depositional evolution and corresponding sedimentary architecture.However,autogenic processes are often affected by changing allogenic factors and are difficult to be identified and analyzed from modern and ancient records.Through the flume tank experiment under constant boundary conditions,the depositional process,evolution principles,and the sedimentary architecture of a river-dominated delta was presented,and a corresponding sedimentary architecture model was constructed.The evolution of river-dominated delta controlled only by autogenic process is obviously periodic,and each autogenic cycle can be divided into an initial progradational stage,a middle retrogratational stage,and a late aggradational–progradational stage.In the initial progradational stage,one feeder channel incised into the delta plain,mouth bar(s)was formed in front of the channel mouth,and small-scale crevasse splays were formed on the delta plain.In the middle retrogradational stage,the feeder channel was blocked by the mouth bar(s)which grew out of water at the end of the initial stage,and a set of large-scale distributary splay complexes were formed on the delta plain.These distributary splay complexes were retrogradationally overlapped due to the continuous migration of the bifurcation point of the feeder channel.In the late aggradational–progradational stage,the feeder channel branched into several radial distributary channels,overlapped distributary channels were formed on the delta plain,and terminal lobe complexes were formed at the end of distributary channels.The three sedimentary layers formed in the three stages constituted an autogenic succession.The experimental delta consisted of six autogenic depositional successions.Dynamic allocation of accommodation space and the following adaptive sediments filling were the two main driving factors of the autogenic evolution of deltas.

Effect of Pre-wetted Light-weight Aggregate on Internal RelativeHumidity and Autogenous Shrinkage of Concrete

This research indicates that the gradient of internal relative humidity （IRH） decreases rapidly within 7-day curing age in HPC. The amount of water imported by pre-wetted light-weight aggregate can regulate IRH of concrete. By importing a proper amount of water, the process of the decline of IRH can be delayed and the autogenous shrinkage can be reduced. The relationship among the amount of water imported by pre- wetted lightweight aggregate, IRH and AS was established. The result provides a new method of reducing early AS and enhancing early cracking resistance of HPC.

Effects of Shale and CaO Incorporation on Mechanical Properties and Autogenous Deformation of Early-age Concrete

The pre-soaked shale employed as an internal curing agent and CaO employed as expansion agent were incorporated into concrete to investigate their effects on the mechanical properties and autogenous deformation of early-age concrete.We have conducted the relevant tests for setting time,mechanical properties,internal relative humidity and autogenous deformation of early-age concrete with shale or/and CaO incorporation.The results indicate that the set behavior is delayed by shale addition but is accelerated with CaO.The shale addition firstly enhances and subsequently decreases the strength,but CEA addition has a weakening effect.Additionally,shale or/and CaO incorporation deteriorates the elastic modulus.The shale and CaO incorporation significantly improve the internal relative humidity of concrete.The internal curing efficacy of shale could synergistically mitigate the autogenous shrinkage,that is,could enhance the expansion of CaO and then greatly reduce the contraction,which is significantly beneficial to impede the shrinkage-introduced cracks of early-age concrete.

Autogenous Shrinkage of High Strength Lightweight Aggregate Concrete

The characteristic of autogenous shrinkage（AS） and its effect on high strength lightweight aggregate concrete（HSLAC） were studied.The experimental results show that the main shrinkage of high strength concrete is AS and the amount of cement can affect the AS of HSLAC remarkably,At the early stage the AS of HSLAC is lower than that of high strength normal concrete,but it has a large growth at the later stage.The AS of high strength normal concrete becomes stable at 90d age,but HSLAC still has a high AS growth .It is found that adjusting the volume rate of lightweight aggregate,mixing with a proper dosage of fly ash and raising the water saturation degree of lightweight aggregate can markedly reduce the AS rate of HSLAC.

Mesocosmic study on autogenous shrinkage of concrete with consideration of effects of temperature and humidity

A study on the autogenous shrinkage （AS） of concrete from a mesocosmic perspective was carried out using numerical simulation technology. The temperature history and the autogenous relative humidity （ARH）, two factors that have been shown to have occasional influence on this process in previous studies, were introduced into this study. According to these concepts, a program for simulation of the temperature field, humidity field, and stress field based on the equivalent age method and a fully automatic aggregate modeling tool were used. With the help of these programs, the study of a small concrete specimen provided some useful conclusions： the aggregate and the matrix show distinct distribution properties in the temperature field, humidity field, and stress field; the aggregate-matrix interface has a high possibility of becoming the location of the initial cracking caused by AS of concrete; the distribution of random aggregates is extremely important for mesoscopical analysis; and the temperature history is the main factor affecting the AS of concrete. On the whole, inherent mechanisms and cracking mechanisms of AS of concrete can be explained more reasonably and realistically only by considering the different characteristics of material phases and the effects of temperature and humidity.

Self-desiccation mechanism of high-performance concrete

Investigations on the effects of W/C ratio and silica fume on the autogenous shrinkage and internal relative humidity of high performance concrete (HPC), and analysis of the self-desiccation mechanisms of HPC showed that the autogenous shrinkage and internal relative humidity of HPC increases and decreases with the reduction of W/C respectively; and that these phenomena were amplified by the addition of silica fume. Theoretical analyses indicated that the reduction of RH in HPC was not due to shortage of water, but due to the fact that the evaporable water in HPC was not evaporated freely. The reduction of internal relative humidity or the so-called self-desiccation of HPC was chiefly caused by the increase in mole concentration of soluble ions in HPC and the reduction of pore size or the increase in the fraction of micro-pore water in the total evaporable water (Tr/Tte ratio).

Autogenous Bone Graft versus Artificial Substitutes in Cranioplasty

Cranioplasty is a routine procedure in neurosurgery. However, it has a high postoperative complication rate up to 40%. The lack of good prospective studies and the small number of patients who receive artificial substitutes make it difficult to choose between different materials and the decision is mostly based on subjective or economic reasons. The main goal of this study was to compare the most common complications related to the implant within the first year after implantation. Methods: This prospective randomized clinical study has been carried out on 32 patients with cranial defects of different etiologies, sites and sizes which have been operated in Assiut University Hospital from January 2016 to January 2017. The patients were randomized into two groups: Autologous and Artificial group. Each group has 16 patients. Results: The overall complication rate in autologous group was found to be (25%) and in artificial group (37.5%). Infection in autologous group was found in (6.25%), in artificial group was found in (12.5%). Bone resorption was found in (12.5%). For epidural hematoma and wound dehiscence each has a rate of (6.25%). Poor cosmetic result in (18.75%) of artificial group. Conclusion: Cranioplasty is not without complications. However, good decision making, good timing and proper surgical techniques can provide excellent results. Primary titanium mesh cranioplasty should be considered especially in young adult patients with traumatic aetiology of bone defect.

Influence of Repeated Variable Load on Long-Term Behavior of Concrete Elements

The objective of this paper is to study the influence of repeated variable action on long-term behavior of concrete structural elements using quasi-permanent combination of actions, for the assessment of long-term effects （e.g., effects due to creep and shrinkage in concrete structures）, as it is proposed in Eurocodes. Extensive experimental program and analytical research using model B3 and AAEM （age adjusted effective modulus） method was performed in order to define quasi-permanent factor ψ2, for two specific loading histories. These loading histories were consist of long-term permanent action ＂G＂ and repeated variable action ＂Q＂. The variable load was applied in cycles of loading/unloading for 24 h and 48 h in period of 400 days appropriately for one series of concrete elements. 24 reinforced concrete beams, dimensions 150 mm × 280 mm × 3,000 mm, were tested. Twelve beams were made of concrete class C30/37 and 12 of concrete class C60/75.

Effect of swimming training on neural microcirculation in rats with sciatic nerve compression A study based on laser Doppler flowmetry

Microcirculation of the peripheral nerve is necessary for neural growth and regeneration. However, technical limitations have limited studies in this area. The few studies conducted have concerned active exercise effects on microcirculation of the peripheral nerve. Using an animal experiment, this study evaluated the effect of swimming training on microcirculation of injured peripheral nerve by laser Doppler flowmetry. The results showed that the blood vessel at the distal end of the peripheral nerve was the main blood supply for the nerve, and the internal blood supply for the nerve had strong compensatory ability. Swimming training promoted the functional recovery of rats with sciatic nerve injury and the regeneration of myelin sheath and blood vessels, but had no impact on neural blood flow.

SELECTION OF THE PROCESS PARAMETERS FOR BATH AUTOGENOUS SMELTING OF COPPER

The process parameters for bath autogenous smelting of copper were selected based on dynamic analysis of the experimental data and calculation of the mathematical model. Selecting the slag composition of SiO2/Fe=0.80 and CaO％=16. desulphur ratio less than 80 wt.-％ in system. and the copper content of matte less than 60 wt.-％, it is able to limit Fe3O4 formation and obtain a high desulphurization. The critical oxygen content of the blast increased with decrease of the sulphur content of the concentrate and increase of copper contents of the matte. If the copper contents of the concentrate are respectively of 30 and 35 wt.-％, the critical oxygen contents of the blast will be 48 and 69 wt.-％ respectively. The smelling rate increases linearly with the blast intensity. When the sulphur content of the concentrate is 30 wt.-％, the oxygen content of the blast 70 vol.-％ and the copper content of the matte 60 wt.-％, a blast intensityy of 700 Nm3/m2·h results in a smeling rate of 48.81 t/m2·d.

Neither Ghost nor Machine:The Emergence and Nature of Selves

Every generation marvels at what prior generations did not not know,the mysteries they had not not yet solved,perhaps had not not even noticed.We might,therefore,wonder what future generations will regard as our biggest blind spot.What central mystery have not not we solved yet and perhaps even do not not recognize to be a mystery?Here,I will propose a likely candidate:Scientists have yet to explain the emergence and nature of striving selves.I will also summarize a new explanation developed by biologist Terrence Deacon.By selves,I mean all living beings ever,here on earth or anywhere in the universe.They go by different names- agents,individuals,living beings,organisms.I will simply refer to them as selves and refer to all inanimate objects and processes as non-selves.

Self-desiccation Effect of High Performance Concrete

Effects of water to binder ratio (m(W)/m(B)), types and addition content of mineral admixtures ont he autogenous relative humidity (ARH) change of concrete resulting from self-desiccation were studies. The parameters of coefficient of mineral self-desiccation-effect ka nd efficient water to binder ratio r(e) were proposed, and experimental results were fitted non-linearly and analyzed using these proposed parameters. The experimental results indicate that ARH reduction of concrete at different ages increases with the decrease of m(W)/m(B). The ARH changes laws of concrete with m(W)/m(B) lower than 0.4 can be expressed with a non-linear equation. The extent of the effect of types and addition content of mineral admixures on ARH reduction of concrete resulting from self-desiccation can be reflected by the non-linear equation with the parameter of efficient water to binder ratio r(e) effectively.

Treatment of microtia:past,present and future

The purpose of this review article is to review the reconstructive method available for the treatment of microtia and highlight the recent advances.The well established technique developed by Brent and Nagata are still must widely performed procedure for microtia reconstruction.Various modification of this technique has been reported in the literature.Synthetic framework is seen as an alternative to autogenous costal cartilage framework because of ease of the procedure.More recently,tissue engineering is seen as the most promising treatment.This article gives an overview of the current practice in the field of microtia reconstruction and summarizes the recent surgical developments and relevant tissue engineering research.